Federal Register, Volume 68 Issue 154 (Monday, August 11, 2003)

[Federal Register Volume 68, Number 154 (Monday, August 11, 2003)]
[Proposed Rules]
[Pages 47640-47795]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 03-18295]

[[Page 47639]]

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Part II

Environmental Protection Agency

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40 CFR Parts 141 and 142

National Primary Drinking Water Regulations: Long Term 2 Enhanced
Surface Water Treatment Rule; Proposed Rule

Federal Register / Vol. 68, No. 154 / Monday, August 11, 2003 /
Proposed Rules

[[Page 47640]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 141 and 142

[FRL-7530-5]
RIN 2040--AD37

National Primary Drinking Water Regulations: Long Term 2 Enhanced
Surface Water Treatment Rule

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: In this document, the Environmental Protection Agency (EPA) is
proposing National Primary Drinking Water Regulations that require the
use of treatment techniques, along with monitoring, reporting, and
public notification requirements, for all public water systems (PWSs)
that use surface water sources. The purposes of the Long Term 2
Enhanced Surface Water Treatment Rule (LT2ESWTR) are to improve control
of microbial pathogens, including specifically the protozoan
Cryptosporidium, in drinking water and to address risk-risk trade-offs
with the control of disinfection byproducts. Key provisions in today's
proposed LT2ESWTR include the following: source water monitoring for
Cryptosporidium, with reduced monitoring requirements for small
systems; additional Cryptosporidium treatment for filtered systems
based on source water Cryptosporidium concentrations; inactivation of
Cryptosporidium by all unfiltered systems; disinfection profiling and
benchmarking to ensure continued levels of microbial protection while
PWSs take the necessary steps to comply with new disinfection byproduct
standards; covering, treating, or implementing a risk management plan
for uncovered finished water storage facilities; and criteria for a
number of treatment and management options (i.e., the microbial
toolbox) that PWSs may implement to meet additional Cryptosporidium
treatment requirements. The LT2ESWTR will build upon the treatment
technique requirements of the Interim Enhanced Surface Water Treatment
Rule and the Long Term 1 Enhanced Surface Water Treatment Rule.
EPA believes that implementation of the LT2ESWTR will significantly
reduce levels of Cryptosporidium in finished drinking water. This will
substantially lower rates of endemic cryptosporidiosis, the illness
caused by Cryptosporidium, which can be severe and sometimes fatal in
sensitive subpopulations (e.g., AIDS patients, the elderly). In
addition, the treatment technique requirements of this proposal are
expected to increase the level of protection from exposure to other
microbial pathogens (e.g., Giardia lamblia).

DATES: EPA must receive public comment on the proposal by November 10,
2003.

ADDRESSES: Comments may be submitted by mail to: Water Docket,
Environmental Protection Agency, Mail Code 4101T, 1200 Pennsylvania
Ave., NW., Washington, DC 20460, Attention Docket ID No. OW-2002-0039.
Comments may also be submitted electronically or through hand delivery/
courier by following the detailed instructions as provided in section
I.C. of the SUPPLEMENTARY INFORMATION section.

FOR FURTHER INFORMATION CONTACT: For technical inquiries, contact
Daniel Schmelling, Office of Ground Water and Drinking Water (MC
4607M), U.S. Environmental Protection Agency, 1200 Pennsylvania Ave.,
NW., Washington, DC 20460; telephone (202) 564-5281. For regulatory
inquiries, contact Jennifer McLain at the same address; telephone (202)
564-5248. For general information contact the Safe Drinking Water
Hotline, Telephone (800) 426-4791. The Safe Drinking Water Hotline is
open Monday through Friday, excluding legal holidays, from 9 a.m. to
5:30 p.m. Eastern Time.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Who Is Regulated by This Action?

Entities potentially regulated by the LT2ESWTR are public water
systems (PWSs) that use surface water or ground water under the direct
influence of surface water (GWUDI). Regulated categories and entities
are identified in the following chart.

------------------------------------------------------------------------
Category Examples of regulated entities
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Industry............................... Public Water Systems that use
surface water or ground water
under the direct influence of
surface water.
State, Local, Tribal or Federal Public Water Systems that use
Governments. surface water or ground water
under the direct influence of
surface water.
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This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This table lists the types of entities that EPA is now aware
could potentially be regulated by this action. Other types of entities
not listed in this table could also be regulated. To determine whether
your facility is regulated by this action, you should carefully examine
the definition of public water system in Sec. 141.3 of Title 40 of the
Code of Federal Regulations and applicability criteria in Sec. Sec.
141.76 and 141.501 of today's proposal. If you have questions regarding
the applicability of the LT2ESWTR to a particular entity, consult one
of the persons listed in the preceding section entitled FOR FURTHER
INFORMATION CONTACT

B. How Can I Get Copies of This Document and Other Related Information?

1. Docket. EPA has established an official public docket for this
action under Docket ID No. OW-2002-0039. The official public docket
consists of the documents specifically referenced in this action, any
public comments received, and other information related to this action.
Although a part of the official docket, the public docket does not
include Confidential Business Information (CBI) or other information
whose disclosure is restricted by statute. The official public docket
is the collection of materials that is available for public viewing at
the Water Docket in the EPA Docket Center, (EPA/DC) EPA West, Room
B102, 1301 Constitution Ave., NW., Washington, DC. The EPA Docket
Center Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday
through Friday, excluding legal holidays. The telephone number for the
Public Reading Room is (202) 566-1744, and the telephone number for the
Water Docket is (202) 566-2426. For access to docket material, please
call (202) 566-2426 to schedule an appointment.
2. Electronic Access. You may access this Federal Register document
electronically through the EPA Internet under the ``Federal Register''
listings at http://www.epa.gov/fedrgstr/.
An electronic version of the public docket is available through
EPA's electronic public docket and comment system, EPA Dockets. You may
use EPA Dockets at http://www.epa.gov/edocket/ to submit or view public
comments, access the index listing of the contents of the official
public docket, and to access those documents in the public docket that
are available electronically. Once in the system, select ``search,''
then key in the appropriate docket identification number.
Certain types of information will not be placed in the EPA Dockets.
Information claimed as CBI and other

[[Page 47641]]

information whose disclosure is restricted by statute, which is not
included in the official public docket, will not be available for
public viewing in EPA's electronic public docket. EPA's policy is that
copyrighted material will not be placed in EPA's electronic public
docket but will be available only in printed, paper form in the
official public docket. Although not all docket materials may be
available electronically, you may still access any of the publicly
available docket materials through the docket facility identified in
section I.B.1.
For public commenters, it is important to note that EPA's policy is
that public comments, whether submitted electronically or in paper,
will be made available for public viewing in EPA's electronic public
docket as EPA receives them and without change, unless the comment
contains copyrighted material, CBI, or other information whose
disclosure is restricted by statute. When EPA identifies a comment
containing copyrighted material, EPA will provide a reference to that
material in the version of the comment that is placed in EPA's
electronic public docket. The entire printed comment, including the
copyrighted material, will be available in the public docket.
Public comments submitted on computer disks that are mailed or
delivered to the docket will be transferred to EPA's electronic public
docket. Public comments that are mailed or delivered to the Docket will
be scanned and placed in EPA's electronic public docket. Where
practical, physical objects will be photographed, and the photograph
will be placed in EPA's electronic public docket along with a brief
description written by the docket staff.

C. How and to Whom Do I Submit Comments?

You may submit comments electronically, by mail, or through hand
delivery/courier. To ensure proper receipt by EPA, identify the
appropriate docket identification number in the subject line on the
first page of your comment. Please ensure that your comments are
submitted within the specified comment period. Comments received after
the close of the comment period will be marked ``late.'' EPA is not
required to consider these late comments.
1. Electronically. If you submit an electronic comment as
prescribed below, EPA recommends that you include your name, mailing
address, and an e-mail address or other contact information in the body
of your comment. Also include this contact information on the outside
of any disk or CD ROM you submit, and in any cover letter accompanying
the disk or CD ROM. This ensures that you can be identified as the
submitter of the comment and allows EPA to contact you in case EPA
cannot read your comment due to technical difficulties or needs further
information on the substance of your comment. EPA's policy is that EPA
will not edit your comment, and any identifying or contact information
provided in the body of a comment will be included as part of the
comment that is placed in the official public docket, and made
available in EPA's electronic public docket. If EPA cannot read your
comment due to technical difficulties and cannot contact you for
clarification, EPA may not be able to consider your comment.
a. EPA Dockets. Your use of EPA's electronic public docket to
submit comments to EPA electronically is EPA's preferred method for
receiving comments. Go directly to EPA Dockets at http://www.epa.gov/
edocket, and follow the online instructions for submitting comments.
Once in the system, select ``search,'' and then key in Docket ID No.
OW-2002-0039. The system is an ``anonymous access'' system, which means
EPA will not know your identity, e-mail address, or other contact
information unless you provide it in the body of your comment.
b. E-mail. Comments may be sent by electronic mail (e-mail) to OW-
Docket@epa.gov, Attention Docket ID No. OW-2002-0039. In contrast to
EPA's electronic public docket, EPA's e-mail system is not an
``anonymous access'' system. If you send an e-mail comment directly to
the Docket without going through EPA's electronic public docket, EPA's
e-mail system automatically captures your e-mail address. E-mail
addresses that are automatically captured by EPA's e-mail system are
included as part of the comment that is placed in the official public
docket, and made available in EPA's electronic public docket.
c. Disk or CD ROM. You may submit comments on a disk or CD ROM that
you mail to the mailing address identified in section I.C.2. These
electronic submissions will be accepted in WordPerfect or ASCII file
format. Avoid the use of special characters and any form of encryption.
2. By Mail. Send three copies of your comments and any enclosures
to: Water Docket, Environmental Protection Agency, Mail Code 4101T,
1200 Pennsylvania Ave., NW., Washington, DC, 20460, Attention Docket ID
No. OW-2002-0039.
3. By Hand Delivery or Courier. Deliver your comments to: Water
Docket, EPA Docket Center, Environmental Protection Agency, Room B102,
1301 Constitution Ave., NW, Washington, DC, Attention Docket ID No. OW-
2002-0039. Such deliveries are only accepted during the Docket's normal
hours of operation as identified in section I.B.1.

D. What Should I Consider as I Prepare My Comments for EPA?

You may find the following suggestions helpful for preparing your
comments:
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide any technical information and/or data you used that
support your views.
4. If you estimate potential burden or costs, explain how you
arrived at your estimate.
5. Provide specific examples to illustrate your concerns.
6. Offer alternatives.
7. Make sure to submit your comments by the comment period deadline
identified.
8. To ensure proper receipt by EPA, identify the appropriate docket
identification number in the subject line on the first page of your
response. It would also be helpful if you provided the name, date, and
Federal Register citation related to your comments.

Abbreviations Used in This Document

AIPC All Indian Pueblo Council
ASDWA Association of State Drinking Water Administrators
ASTM American Society for Testing and Materials
AWWA American Water Works Association
AWWARF American Water Works Association Research Foundation
[deg]C Degrees Centigrade
CCP Composite Correction Program
CDC Centers for Disease Control and Prevention
CFE Combined Filter Effluent
CFR Code of Federal Regulations
COI Cost-of-Illness
CT The Residual Concentration of Disinfectant (mg/L) Multiplied by the
Contact Time (in minutes)
CWS Community Water Systems
DAPI 4',6-Diamindino-2-phenylindole
DBPs Disinfection Byproducts
DBPR Disinfectants/Disinfection Byproducts Rule
DE Diatomaceous Earth
DIC Differential Interference Contrast (microscopy)
EA Economic Analysis

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EPA United States Environmental Protection Agency
GAC Granular Activated Carbon
GWUDI Ground Water Under the Direct Influence of Surface Water
HAA5 Haloacetic acids (Monochloroacetic, Dichloroacetic,
Trichloroacetic, Monobromoacetic and Dibromoacetic Acids)
HPC Heterotrophic Plate Count
ICR Information Collection Request
ICRSS Information Collection Rule Supplemental Surveys
ICRSSM Information Collection Rule Supplemental Survey of Medium
Systems
ICRSSL Information Collection Rule Supplemental Survey of Large Systems
IESWTR Interim Enhanced Surface Water Treatment Rule
IFA Immunofluorescence Assay
Log Logarithm (common, base 10)
LRAA Locational Running Annual Average
LRV Log Removal Value
LT1ESWTR Long Term 1 Enhanced Surface Water Treatment Rule
LT2ESWTR Long Term 2 Enhanced Surface Water Treatment Rule
MCL Maximum Contaminant Level
MCLG Maximum Contaminant Level Goal
MGD Million Gallons per Day
M-DBP Microbial and Disinfectants/Disinfection Byproducts
MF Microfiltration
NCWS Non-community water systems
NF Nanofiltration
NODA Notice of Data Availability
NPDWR National Primary Drinking Water Regulation
NTNCWS Non-transient Non-community Water System
NTTAA National Technology Transfer and Advancement Act
NTU Nephelometric Turbidity Unit
OMB Office of Management and Budget
PE Performance Evaluation
PWS Public Water System
QC Quality Control
QCRV Quality Control Release Value
RAA Running Annual Average
RFA Regulatory Flexibility Act
RO Reverse Osmosis
RSD Relative Standard Deviation
SAB Science Advisory Board
SBAR Small Business Advocacy Review
SERs Small Entity Representatives
SDWA Safe Drinking Water Act
SWTR Surface Water Treatment Rule
TCR Total Coliform Rule
TTHM Total Trihalomethanes
TNCWS Transient Non-community Water Systems
UF Ultrafiltration
UMRA Unfunded Mandates Reform Act

Table of Contents

I. Summary
A. Why Is EPA Proposing the LT2ESWTR?
B. What Does the LT2ESWTR Proposal Require?
1. Treatment Requirements for Cryptosporidium
2. Disinfection Profiling and Benchmarking
3. Uncovered Finished Water Storage Facilities
C. Will This Proposed Regulation Apply to My Water System?
II. Background
A. What Is the Statutory Authority for the LT2ESWTR?
B. What Current Regulations Address Microbial Pathogens in
Drinking Water?
1. Surface Water Treatment Rule
2. Total Coliform Rule
3. Interim Enhanced Surface Water Treatment Rule
4. Long Term 1 Enhanced Surface Water Treatment Rule
5. Filter Backwash Recycle Rule
C. What Public Health Concerns Does This Proposal Address?
1. Introduction
2. Cryptosporidium Health Effects and Outbreaks
a. Health Effects
b. Waterborne Cryptosporidiosis Outbreaks.
3. Remaining Public Health Concerns Following the IESWTR and
LT1ESWTR
a. Adequacy of Physical Removal To Control Cryptosporidium and
the Need for Risk Based Treatment Requirements.
b. Control of Cryptosporidium in Unfiltered Systems
c. Uncovered Finished Water Storage Facilities
D. Federal Advisory Committee Process
III. New Information on Cryptosporidium Health Risks and Treatment
A. Overview of Critical Factors for Evaluating Regulation of
Microbial Pathogens
B. Cryptosporidium Infectivity
1. Cryptosporidium Infectivity Data Evaluated for IESWTR
2. New Data on Cryptosporidium Infectivity
3. Significance of New Infectivity Data
C. Cryptosporidium Occurrence
1. Occurrence Data Evaluated for IESWTR
a. Filtered Systems.
b. Unfiltered Systems
2. Overview of the Information Collection Rule and Information
Collection Rule Supplemental Surveys (ICRSS)
a. Scope of the Information Collection Rule
b. Scope of the ICRSS
3. Analytical Methods for Protozoa in the Information Collection
Rule and ICRSS
a. Information Collection Rule Protozoan Method
b. Method 1622 and Method 1623
4. Cryptosporidium Occurrence Results from the Information
Collection Rule and ICRSS
a. Information Collection Rule Results
b. ICRSS Results
5. Significance of New Cryptosporidium Occurrence Data
6. Request for Comment on Information Collection Rule and ICRSS
Data Sets
D. Treatment
1. Overview
2. Treatment Information Considered for the IESWTR and LT1ESWTR
a. Physical Removal
b. Inactivation
3. New Information on Treatment for Control of Cryptosporidium
a. Conventional Filtration Treatment and Direct Filtration
i. Dissolved Air Flotation.
b. Slow Sand Filtration
c. Diatomaceous Earth Filtration
d. Other Filtration Technologies
e. Inactivation
i. Ozone and Chlorine Dioxide
ii. Ultraviolet Light
iii. Significance of New Information on Inactivation
IV. Discussion of Proposed LT2ESWTR Requirements
A. Additional Cryptosporidium Treatment Technique Requirements
for Filtered Systems
1. What Is EPA Proposing Today?
a. Overview of Framework Approach
b. Monitoring Requirements
c. Treatment Requirements
i. Bin Classification
ii. Credit for Treatment in Place
iii. Treatment Requirements Associated With LT2ESWTR Bins
d. Use of Previously Collected Data
2. How Was This Proposal Developed?
a. Basis for Targeted Treatment Requirements
b. Basis for Bin Concentration Ranges and Treatment Requirements
i. What Is the Risk Associated With a Given Level of
Cryptosporidium in a Drinking Water Source?
ii. What Degree of Additional Treatment Should Be Required for a
Given Source Water Cryptosporidium Level?
c. Basis for Source Water Monitoring Requirements
i. Systems Serving at Least 10,000 People
ii. Systems Serving Fewer Than 10,000 People
iii. Future Monitoring and Reassessment
d. Basis for Accepting Previously Collected Data
3. Request for Comment
B. Unfiltered System Treatment Technique Requirements for
Cryptosporidium
1. What Is EPA Proposing Today?
a. Overview
b. Monitoring Requirements
c. Treatment Requirements
2. How Was This Proposal Developed?
a. Basis for Cryptosporidium Treatment Requirements
b. Basis for Requiring the Use of Two Disinfectants
c. Basis for Source Water Monitoring Requirements
3. Request for Comment
C. Options for Systems to Meet Cryptosporidium Treatment
Requirements
1. Microbial Toolbox Overview
2. Watershed Control Program
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
3. Alternative Source

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a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
4. Off-stream Raw Water Storage
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
5. Pre-sedimentation With Coagulant
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
i. Published Studies of Cryptosporidium Removal by Conventional
Sedimentation Basins
ii. Data Supplied by Utilities on the Removal of Spores by
Presedimentation
c. Request for Comment
6. Bank Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
7. Lime Softening
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
8. Combined Filter Performance
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
9. Roughing Filter
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
10. Slow Sand Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
11. Membrane Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
12. Bag and Cartridge Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
13. Secondary Filtration
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
14. Ozone and Chlorine Dioxide
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comments
15. Ultraviolet Light
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
16. Individual Filter Performance
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
17. Other Demonstration of Performance
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
D. Disinfection Benchmarks for Giardia lamblia and Viruses
1. What Is EPA Proposing Today?
a. Applicability and Schedule
b. Developing the Disinfection Profile and Benchmark
c. State Review
2. How Was This Proposal Developed?
3. Request for Comments
E. Additional Treatment Technique Requirements for Systems with
Uncovered Finished Water Storage Facilities
1. What Is EPA Proposing Today?
2. How Was This Proposal Developed?
3. Request for Comments
F. Compliance Schedules
1. What Is EPA Proposing Today?
a. Source Water Monitoring
i. Filtered Systems
ii. Unfiltered Systems
b. Treatment Requirements
c. Disinfection Benchmarks for Giardia lamblia and Viruses
2. How Was This Proposal Developed?
3. Request for Comments
G. Public Notice Requirements
1. What Is EPA Proposing Today?
2. How Was This Proposal Developed?
3. Request for Comment
H. Variances and Exemptions
1. Variances
2. Exemptions
3. Request for Comment
a. Variances
b. Exemptions
I. Requirements for Systems To Use Qualified Operators
J. System Reporting and Recordkeeping Requirements
1. Overview
2. Reporting Requirements for Source Water Monitoring
a. Data Elements To Be Reported
b. Data System
c. Previously Collected Monitoring Data
3. Compliance With Additional Treatment Requirements
4. Request for Comment
K. Analytical Methods
1. Cryptosporidium
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
2. E. coli
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
3. Turbidity
a. What Is EPA Proposing Today?
b. How Was This Proposal Developed?
c. Request for Comment
L. Laboratory Approval
1. Cryptosporidium Laboratory Approval
2. E. coli Laboratory Approval
3. Turbidity Analyst Approval
4. Request for Comment
M. Requirements for Sanitary Surveys Conducted by EPA
1. Overview
2. Background
3. Request for Comment
V. State Implementation
A. Special State Primacy Requirements
B. State Recordkeeping Requirements
C. State Reporting Requirements
D. Interim Primacy
VI. Economic Analysis
A. What Regulatory Alternatives Did the Agency Consider?
B. What Analyses Support Selecting the Proposed Rule Option?
C. What Are the Benefits of the Proposed LT2ESWTR?
1. Non-quantifiable Health and Non-health Related Benefits
2. Quantifiable Health Benefits
a. Filtered Systems
b. Unfiltered Systems
3. Timing of Benefits Accrual (latency)
D. What Are the Costs of the Proposed LT2ESWTR?
1. Total Annualized Present Value Costs
2. Water System Costs
a. Source Water Monitoring Costs
b. Filtered Systems Treatment Costs
c. Unfiltered Systems Treatment Costs
d. Uncovered Finished Water Storage Facilities
e. Future Monitoring Costs
f. Sensitivity Analysis-influent Bromide Levels on Technology
Selection for Filtered Plants
3. State/Primacy Agency Costs
4. Non-quantified Costs
E. What Are the Household Costs of the Proposed Rule?
F. What Are the Incremental Costs and Benefits of the Proposed
LT2ESWTR?
G. Are There Benefits From the Reduction of Co-occurring
Contaminants?
H. Are There Increased Risks From Other Contaminants?
I. What Are the Effects of the Contaminant on the General
Population and Groups Within the General Populations That Are
Identified as Likely to be at Greater Risk of Adverse Health
Effects?
J. What Are the Uncertainties in the Baseline, Risk, Benefit,
and Cost Estimates for the Proposed LT2ESWTR as well as the Quality
and Extent of the Information?
K. What Is the Benefit/Cost Determination for the Proposed
LT2ESWTR?
L. Request for Comment
VII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
1. Summary of UMRA Requirements
2. Written Statement for Rules With Federal mandates of $100
million or more
a. Authorizing Legislation
b. Cost-benefit Analysis
c. Estimates of Future Compliance Costs and Disproportionate
Budgetary Effects
d. Macro-economic Effects
e. Summary of EPA Consultation With State, local, and Tribal
Governments and Their Concerns
f. Regulatory Alternatives Considered
g. Selection of the Least Costly, Most Cost-effective, or Least
Burdensome Alternative That Achieves the Objectives of the Rule
3. Impacts on Small Governments
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children from
Environmental Health and Safety Risks
H. Executive Order 13211: Actions that Significantly Affect
Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act
J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations or Low-Income
Populations

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K. Consultations With the Science Advisory Board, National
Drinking Water Advisory Council, and the Secretary of Health and
Human Services
L. Plain Language
VIII. References

I. Summary

A. Why Is EPA Proposing the LT2ESWTR?

EPA is proposing the Long Term 2 Enhanced Surface Water Treatment
Rule (LT2ESWTR) to provide for increased protection against microbial
pathogens in public water systems that use surface water sources. The
proposed LT2ESWTR focuses on Cryptosporidium, which is a protozoan
pathogen that is widespread in surface water. EPA is particularly
concerned about Cryptosporidium because it is highly resistant to
inactivation by standard disinfection practices like chlorination.
Ingestion of Cryptosporidium oocysts can cause acute gastrointestinal
illness, and health effects in sensitive subpopulations may be severe,
including risk of mortality. Cryptosporidium has been identified as the
pathogenic agent in a number of waterborne disease outbreaks across the
U.S. and in Canada (details in section II).
The intent of the LT2ESWTR is to supplement existing microbial
treatment requirements for systems where additional public health
protection is needed. Currently, the Interim Enhanced Surface Water
Treatment Rule (IESWTR) requires large systems that filter to remove at
least 99% (2 log) of Cryptosporidium (63 FR 69478, December 16, 1998)
(USEPA 1998a). The Long Term 1 Enhanced Surface Water Treatment Rule
(LT1ESWTR) extends this requirement to small systems (67 FR 1812,
January 14, 2002) (USEPA 2002a). Subsequent to promulgating these
regulations, EPA has evaluated significant new data on Cryptosporidium
infectivity, occurrence, and treatment (details in section III). These
data indicate that current treatment requirements achieve adequate
protection for the majority of systems, but there is a subset of
systems with higher vulnerability to Cryptosporidium where additional
treatment is necessary.
Specifically, national survey data show that average
Cryptosporidium occurrence in filtered systems is lower than previously
estimated. However, these data also demonstrate that Cryptosporidium
concentrations vary widely among systems, and that a fraction of
filtered systems have relatively high levels of source water
Cryptosporidium contamination. Based on this finding, along with new
data suggesting that the infectivity (i.e., virulence) of
Cryptosporidium may be substantially higher than previously understood,
EPA has concluded that the current 2 log removal requirement does not
provide an adequate degree of treatment in filtered systems with the
highest source water Cryptosporidium levels. Consequently, EPA is
proposing targeted additional treatment requirements under the LT2ESWTR
for filtered systems with the highest Cryptosporidium risk.
Under current regulations, unfiltered systems are not required to
provide any treatment for Cryptosporidium. New occurrence data suggest
that typical Cryptosporidium levels in the treated water of unfiltered
systems are substantially higher than in the treated water of filtered
systems. Hence, Cryptosporidium treatment by unfiltered systems is
needed to achieve equivalent public health protection. Recent treatment
studies have allowed EPA to develop criteria for systems to inactivate
Cryptosporidium with ozone, ultraviolet (UV) light, and chlorine
dioxide. As a result, EPA has concluded that it is feasible and
appropriate to propose under the LT2ESWTR that all unfiltered systems
treat for Cryptosporidium.
In addition to concern with Cryptosporidium, the LT2ESWTR proposal
is intended to ensure that systems maintain adequate protection against
microbial pathogens as they take steps to reduce formation of
disinfection byproducts (DBPs). Along with the LT2ESWTR, EPA is also
developing a Stage 2 Disinfection Byproducts Rule (DBPR), which will
further limit allowable levels of trihalomethanes and haloacetic acids.
The proposed LT2ESWTR contains disinfection profiling and benchmarking
requirements to ensure that microbial protection is maintained as
systems comply with the Stage 2 DBPR. Also in the proposed LT2ESWTR are
requirements to limit risk associated with existing uncovered finished
water storage facilities. Uncovered storage facilities are subject to
contamination if not properly managed or treated.
Today's proposed LT2ESWTR reflects consensus recommendations from
the Stage 2 Microbial and Disinfection Byproducts (M-DBP) Federal
Advisory Committee. These recommendations are set forth in the Stage 2
M-DBP Agreement in Principle (65 FR 83015, December 29, 2000) (USEPA
2000a).

B. What Does the LT2ESWTR Proposal Require?

1. Treatment Requirements for Cryptosporidium
EPA is proposing risk-targeted treatment technique requirements for
Cryptosporidium control in filtered systems that are based on a
microbial framework approach. Under this approach, systems that use a
surface water or ground water under the direct influence of surface
water (referred to collectively as surface water systems) will conduct
source water monitoring to determine an average Cryptosporidium
concentration. Based on monitoring results, filtered systems will be
classified in one of four possible risk categories (bins). A filtered
system's bin classification determines the extent of any additional
Cryptosporidium treatment requirements beyond the requirements of
current regulations.
EPA expects that the majority of filtered systems will be
classified in the Bin 1, which carries no additional treatment
requirements. Those systems classified Bins 2-4 will be required to
provide from 1.0 to 2.5 log of treatment (i.e., 90 to 99.7 percent
reduction) for Cryptosporidium in addition to conventional treatment
that complies with the IESWTR or LT1ESWTR (details in section IV.A).
Filtered systems will meet additional Cryptosporidium treatment
requirements by using one or more treatment or control steps from a
``microbial toolbox'' of options (details in section IV.C). Rather than
monitoring, filtered systems may elect to comply with the treatment
requirements of Bin 4 directly.
Under the proposed LT2ESWTR, all surface water systems that are not
required to filter (i.e., unfiltered systems) must provide at least 2
log (i.e., 99 percent) inactivation of Cryptosporidium. In addition,
unfiltered systems will monitor for Cryptosporidium in their source
water and must achieve at least 3 log (i.e., 99.9 percent) inactivation
of Cryptosporidium if the mean level exceeds 0.01 oocysts/L.
Alternatively, unfiltered systems may elect to provide 3 log
Cryptosporidium inactivation directly, instead of monitoring. All
requirements established under the Surface Water Treatment Rule (SWTR)
(54 FR 27486, June 29, 1989) (USEPA 1989a) for unfiltered systems will
remain in effect, including 3 log inactivation of Giardia lamblia and 4
log inactivation of viruses. However, the LT2ESWTR proposal requires
that unfiltered systems achieve their overall inactivation requirements
using a

[[Page 47645]]

minimum of two disinfectants (details in section IV.B).
2. Disinfection Profiling and Benchmarking
The purpose of disinfection profiling and benchmarking is to ensure
that when a system makes a significant change to its disinfection
practice, it does not compromise the adequacy of existing microbial
protection. EPA established the disinfection benchmark under the IESWTR
and LT1ESWTR for the Stage 1 M-DBP rules, and the LT2ESWTR proposal
extends disinfection benchmark requirements to apply to the Stage 2 M-
DBP rules.
The proposed profiling and benchmarking requirements are similar to
those promulgated under IESWTR and LT1ESWTR. Systems that meet
specified criteria must prepare disinfection profiles that characterize
current levels of virus and Giardia lamblia inactivation over the
course of one year. Systems with valid operational data from profiling
conducted under the IESWTR or LT1ESWTR are not required to collect
additional data. If a system that is required to prepare a profile
proposes to make a significant change to its disinfection practice, the
system must calculate a disinfection benchmark and must consult with
the State regarding how the proposed change will affect the current
benchmark (details in section IV.D).
3. Uncovered Finished Water Storage Facilities
The proposed LT2ESWTR also includes requirements for systems with
uncovered finished water storage facilities. The IESWTR and LT1ESWTR
require systems to cover all new storage facilities for finished water,
but these rules do not address existing uncovered finished water
storage facilities. Under the LT2ESWTR proposal, systems with uncovered
finished water storage facilities must cover the storage facility or
treat the storage facility discharge to achieve 4 log virus
inactivation unless the State determines that existing risk mitigation
is adequate. Where the State makes such a determination, systems must
develop and implement a risk mitigation plan that addresses physical
access, surface water run-off, animal and bird wastes, and on-going
water quality assessment (details in section IV.E).

C. Will This Proposed Regulation Apply to My Water System?

All community and non-community water systems that use surface
water or ground water under the direct influence of surface water are
affected by the proposed LT2ESWTR.

II. Background

A. What Is the Statutory Authority for the LT2ESWTR?

This section discusses the Safe Drinking Water Act (SDWA or the
Act) sections that direct the development of the LT2ESWTR.
The Act, as amended in 1996, requires EPA to publish a maximum
contaminant level goal (MCLG) and promulgate a national primary
drinking water regulation (NPDWR) with enforceable requirements for any
contaminant that the Administrator determines may have an adverse
effect on the health of persons, is known to occur or there is a
substantial likelihood that the contaminant will occur in public water
systems (PWSs) with a frequency and at levels of public health concern,
and for which in the sole judgement of the Administrator, regulation of
such contaminant presents a meaningful opportunity for health risk
reduction for persons served by PWSs (section 1412 (b)(1)(A)).
MCLGs are non-enforceable health goals, and are to be set at a
level at which no known or anticipated adverse effect on the health of
persons occur and which allows an adequate margin of safety (sections
1412(b)(4) and 1412(a)(3)). EPA established an MCLG of zero for
Cryptosporidium under the IESWTR (63 FR 69478, December 16, 1998)
(USEPA 1998a). The Agency is not proposing any changes to the current
MCLG for Cryptosporidium.
The Act also requires that at the same time EPA publishes an NPDWR
and MCLG, it must specify in the NPDWR a maximum contaminant level
(MCL) which is as close to the MCLG as is feasible (sections 1412(b)(4)
and 1401(1)(c)). The Agency is authorized to promulgate an NPDWR that
requires the use of a treatment technique in lieu of establishing an
MCL if the Agency finds that it is not economically or technologically
feasible to ascertain the level of the contaminant (sections
1412(b)(7)(A) and 1401(1)(C)). The Act specifies that in such cases,
the Agency shall identify those treatment techniques that would prevent
known or anticipated adverse effects on the health of persons to the
extent feasible (section 1412(b)(7)(A)).
The Agency has concluded that it is not currently economically or
technologically feasible for PWSs to determine the level of
Cryptosporidium in finished drinking water for the purpose of
compliance with a finished water standard (the performance of available
analytical methods for Cryptosporidium is described in section III.C;
the treated water Cryptosporidium levels that the LT2ESWTR will achieve
are described in section IV.A). Consequently, today's proposal for the
LT2ESWTR relies on treatment technique requirements to reduce health
risks from Cryptosporidium in PWSs.
When proposing a NPDWR that includes an MCL or treatment technique,
the Act requires EPA to publish and seek public comment on an analysis
of health risk reduction and cost impacts. This includes an analysis of
quantifiable and nonquantifiable costs and health risk reduction
benefits, incremental costs and benefits of each alternative
considered, the effects of the contaminant upon sensitive
subpopulations (e.g., infants, children, pregnant women, the elderly,
and individuals with a history of serious illness), any increased risk
that may occur as the result of compliance, and other relevant factors
(section 1412 (b)(3)(C)). EPA's analysis of health benefits and costs
associated with the proposed LT2ESWTR is presented in ``Economic
Analysis of the LT2ESWTR'' (USEPA 2003a) and is summarized in section
VI of this preamble. However, the Act does not authorize the
Administrator to use additional health risk reduction and cost
considerations to establish MCL or treatment technique requirements for
the control of Cryptosporidium (section 1412 (b)(6)(C)).
Finally, section 1412 (b)(2)(C) of SDWA requires EPA to promulgate
a Stage 2 Disinfectants and Disinfection Byproducts Rule within 18
months after promulgation of the LT1ESWTR, which occurred on January
14, 2002. Consistent with statutory requirements for risk balancing
(section 1412(b)(5)(B)), EPA will finalize the LT2ESWTR with the Stage
2 DBPR to ensure parallel protection from microbial and DBP risks.

B. What Current Regulations Address Microbial Pathogens in Drinking
Water?

This section summarizes the existing regulations that apply to
control of pathogenic microorganisms in surface water systems. These
rules form the baseline of regulatory protection that will be
supplemented by the LT2ESWTR.
1. Surface Water Treatment Rule
The SWTR (54 FR 27486, June 29, 1989) (USEPA 1989a) applies to all
PWSs using surface water or ground water under the direct influence
(GWUDI) of surface water as sources (Subpart H systems). It established

[[Page 47646]]

MCLGs of zero for Giardia lamblia, viruses, and Legionella, and
includes treatment technique requirements to reduce exposure to
pathogenic microorganisms, including: (1) Filtration, unless specified
avoidance criteria are met; (2) maintenance of a disinfectant residual
in the distribution system; (3) removal and/or inactivation of 3 log
(99.9%) of Giardia lamblia and 4 log (99.99%) of viruses; (4) combined
filter effluent turbidity of 5 nephelometric turbidity units (NTU) as a
maximum and 0.5 NTU at 95th percentile monthly for treatment plants
using conventional treatment or direct filtration (with separate
standards for other filtration technologies); and (5) watershed
protection and source water quality requirements for unfiltered
systems.
2. Total Coliform Rule
The Total Coliform Rule (TCR) (54 FR 27544, June 29, 1989) (USEPA
1989b) applies to all PWSs. It established an MCLG of zero for total
and fecal coliform bacteria, and an MCL based on the percentage of
positive samples collected during a compliance period. Coliforms are
used as a screen for fecal contamination and to determine the integrity
of the water treatment process and distribution system. Under the TCR,
no more than 5 percent of distribution system samples collected in any
month may contain coliform bacteria (no more than 1 sample per month
may be coliform positive in those systems that collect fewer than 40
samples per month). The number of samples to be collected in a month is
based on the number of people served by the system.
3. Interim Enhanced Surface Water Treatment Rule
The IESWTR (63 FR 69477, December 16, 1998) (USEPA 1998a) applies
to PWSs serving at least 10,000 people and using surface water or GWUDI
sources. Key provisions established by the IESWTR include the
following: (1) An MCLG of zero for Cryptosporidium; (2) Cryptosporidium
removal requirements of 2 log (99 percent) for systems that filter; (3)
strengthened combined filter effluent turbidity performance standards
of 1.0 NTU as a maximum and 0.3 NTU at the 95th percentile monthly for
treatment plants using conventional treatment or direct filtration; (4)
requirements for individual filter turbidity monitoring; (5)
disinfection benchmark provisions to assess the level of microbial
protection provided as facilities take steps to comply with new DBP
standards; (6) inclusion of Cryptosporidium in the definition of GWUDI
and in the watershed control requirements for unfiltered public water
systems; (7) requirements for covers on new finished water storage
facilities; and (8) sanitary surveys for all surface water systems
regardless of size.
The IESWTR was developed in conjunction with the Stage 1
Disinfectants and Disinfection Byproducts Rule (Stage 1 DBPR) (63 FR
69389; December 16, 1998) (USEPA 1998b), which reduced allowable levels
of certain DBPs, including trihalomethanes, haloacetic acids, chlorite,
and bromate.
4. Long Term 1 Enhanced Surface Water Treatment Rule
The LT1ESWTR (67 FR 1812, January 14, 2002) (USEPA 2002a) builds
upon the microbial control provisions established by the IESWTR for
large systems, through extending similar requirements to small systems.
The LT1ESWTR applies to PWSs using surface water or GWUDI as sources
that serve fewer than 10,000 people. Like the IESWTR, the LT1ESWTR
established the following: 2 log (99 percent) Cryptosporidium removal
requirements for systems that filter; individual filter turbidity
monitoring and more stringent combined filter effluent turbidity
standards for conventional and direct filtration plants; disinfection
profiling and benchmarking; inclusion of Cryptosporidium in the
definition of GWUDI and in the watershed control requirements for
unfiltered systems; and the requirement that new finished water storage
facilities be covered.
5. Filter Backwash Recycle Rule
EPA promulgated the Filter Backwash Recycling Rule (FBRR) (66 FR
31085, June 8, 2001) (USEPA 2001a) to increase protection of finished
drinking water supplies from contamination by Cryptosporidium and other
microbial pathogens. The FBRR requirements will reduce the potential
risks associated with recycling contaminants removed during the
filtration process. The FBRR provisions apply to all systems that
recycle, regardless of population served. In general, the provisions
include the following: (1) Recycling systems must return certain
recycle streams prior to the point of primary coagulant addition unless
the State specifies an alternative location; (2) direct filtration
systems recycling to the treatment process must provide detailed
recycle treatment information to the State; and (3) certain
conventional systems that practice direct recycling must perform a one-
month, one-time recycling self assessment.

C. What Public Health Concerns Does This Proposal Address?

This section presents the basis for the public health concern
associated with Cryptosporidium in drinking water by summarizing
information on Cryptosporidium health effects and outbreaks. This is
followed by a description of the specific areas of public health
concern that remain after implementation of the IESWTR and LT1ESWTR and
that are addressed in the LT2ESWTR proposal. More detailed information
about Cryptosporidium health effects may be found in the following
criteria documents: Cryptosporidium: Human Health Criteria Document
(USEPA 2001b), Cryptosporidium: Drinking Water Advisory (USEPA 2001c),
and Cryptosporidium: Risks for Infants and Children (USEPA 2001d).
1. Introduction
While modern water treatment systems have substantially reduced
waterborne disease incidence, drinking water contamination remains a
significant health risk management challenge. EPA's Science Advisory
Board in 1990 cited drinking water contamination, particularly
contamination by pathogenic microorganisms, as one of the most
important environmental risks (USEPA 1990). This risk is underscored by
information from the Centers for Disease Control and Prevention (CDC)
which indicates that between 1980 and 1998 a total of 419 outbreaks
associated with drinking water were reported, with greater than 511,000
estimated cases of disease. A number of agents were implicated in these
outbreaks, including viruses, bacteria, and protozoa, as well as
several chemicals (Craun and Calderon 1996, Levy et al. 1998, Barwick
et al. 2000). The majority of cases were associated with surface water,
and specifically with the 1993 Cryptosporidium outbreak in Milwaukee,
WI with an estimated 403,000 cases (Mac Kenzie et al. 1994). A recent
study by McDonald et al. (2001), which used blood samples from
Milwaukee children collected during and after the 1993 outbreak,
suggests that Cryptosporidium infection, including asymptomatic
infection, was more widespread than might be inferred from the illness
estimates by Mac Kenzie et al. (1994).
It is important to note that the number of identified and reported
outbreaks in the CDC database is believed to substantially understate
the actual incidence of waterborne disease outbreaks and cases (Craun
and

[[Page 47647]]

Calderon 1996, National Research Council 1997). This under reporting is
due to a number of factors. Many people experiencing gastrointestinal
illness do not seek medical attention. Where medical attention is
provided, the pathogenic agent may not be identified through routine
testing. Physicians often lack sufficient information to attribute
gastrointestinal illness to any specific origin, such as drinking
water, and few States have an active outbreak surveillance program.
Consequently, outbreaks are often not recognized in a community or, if
recognized, are not traced to a drinking water source.
In addition, an unknown but probably significant portion of
waterborne disease is endemic (i.e. isolated cases not associated with
an outbreak) and, thus, is even more difficult to recognize. The
Economic Analysis for the proposed LT2ESWTR (USEPA 2003a) uses data on
Cryptosporidium occurrence, infectivity, and treatment to estimate the
baseline endemic incidence of cryptosporidiosis attributable to
drinking water, as well as the reductions projected as a result of this
rule.
Most waterborne pathogens cause gastrointestinal illness with
diarrhea, abdominal discomfort, nausea, vomiting, and other symptoms.
The effects of waterborne disease are usually acute, resulting from a
single or small number of exposures. Such illnesses are generally of
short duration in healthy people. However, some pathogens, including
Giardia lamblia and Cryptosporidium, may cause disease lasting weeks or
longer in otherwise healthy individuals, though this is not typical for
Cryptosporidium. Waterborne pathogens also cause more serious disorders
such as hepatitis, peptic ulcers, myocarditis, paralysis,
conjunctivitis, swollen lymph glands, meningitis, and reactive
arthritis, and have been associated with diabetes, encephalitis, and
other diseases (Lederberg 1992).
There are populations that are at greater risk from waterborne
disease. These sensitive subpopulations include children (especially
infants), the elderly, the malnourished, pregnant women, the disease
impaired (e.g., diabetes, cystic fibrosis), and a broad category of
those with compromised immune systems, such as AIDS patients, those
with autoimmune disorders (e.g., rheumatoid arthritis, lupus
erythematosus, multiple sclerosis), transplant recipients, and those on
chemotherapy (Rose 1997). This sensitive segment represents almost 20%
of the population in the United States (Gerba et al. 1996). The
severity and duration of illness is often greater in sensitive
subpopulations than in healthy individuals, and in a small percentage
of such cases, death may result.
2. Cryptosporidium Health Effects and Outbreaks
Cryptosporidium is a protozoan parasite that exists in warm-blooded
hosts and, upon excretion, may survive for months in the environment
(Kato et al., 2001). Ingestion of Cryptosporidium can lead to
cryptosporidiosis, a gastrointestinal illness. Transmission of
cryptosporidiosis often occurs through consumption of feces
contaminated food or water, but may also result from direct or indirect
contact with infected persons or animals (Casemore 1990). Surveys
(described in Section III) indicate that Cryptosporidium is common in
surface waters used as drinking water supplies. Sources of
Cryptosporidium contamination include animal agriculture, wastewater
treatment plant discharges, slaughterhouses, birds, wild animals, and
other sources of fecal matter.
EPA is particularly concerned about Cryptosporidium because, unlike
pathogens such as bacteria and most viruses, Cryptosporidium oocysts
are highly resistant to standard disinfectants like chlorine and
chloramines. Consequently, control of Cryptosporidium in most treatment
plants is dependent on physical removal processes. Finished water
monitoring data indicate that Cryptosporidium is sometimes present in
filtered, treated drinking water (LeChevallier et al. 1991; Aboytes et
al. 2002). Moreover, as noted later, many of the individuals sickened
by waterborne outbreaks of cryptosporidiosis were served by filtered
surface water supplies (Solo-Gabriele and Neumeister, 1996). In some
cases, these outbreaks were attributed to treatment deficiencies, while
in other cases the cause was unidentified (see Table II-1).
These data suggest that surface water systems that filter and
disinfect may still be vulnerable to Cryptosporidium, depending on the
source water quality and treatment effectiveness. Today's proposed rule
addresses concern with passage of Cryptosporidium through physical
removal processes during water treatment, as well as in systems lacking
filtration.
a. Health effects. Cryptosporidium infection is characterized by
mild to severe diarrhea, dehydration, stomach cramps, and/or a slight
fever. Symptoms typically last from several days to two weeks, though
in a small percentage of cases, the symptoms may persist for months or
longer in otherwise healthy individuals. Human feeding studies have
demonstrated that a low dose of Cryptosporidium parvum (C. parvum) is
sufficient to cause infection in healthy adults (DuPont et al. 1995,
Chappell et al. 1999, Messner et al. 2001). Studies of immunosuppressed
adult mice have demonstrated that a single viable oocyst can induce
patent C. parvum infections (Yang et al. 2000).
There is evidence that an immune response to Cryptosporidium
exists, but the degree and duration of this immunity is not well
characterized. In a study by Chappell et al. (1999), individuals with a
blood serum antibody (IgG), which can develop from exposure to C.
parvum, demonstrated immunity to low doses of oocysts. The
investigators found the ID50 dose (i.e., dose that infects 50% of the
challenged population) of one C. parvum isolate for adult volunteers
who had pre-existing serum IgG to be 1,880 oocysts in comparison to 132
oocysts for individuals reported as serologically negative. However,
the implications of these data for studies of Cryptosporidium
infectivity are unclear. Earlier work did not observe a correlation
between the development of antibodies after Cryptosporidium exposure
and subsequent protection from illness (Okhuysen et al. 1998). A
subsequent investigation by Muller et al. (2001) observed serological
responses to Cryptosporidium antigens in samples from individuals
reported by Chappel et al. as serologically negative.
Cryptosporidium parvum was first recognized as a human pathogen in
1976 (Juranek 1995). Cases of illness from Cryptosporidium were rarely
reported until 1982 when documented disease incidence increased due to
the AIDS epidemic (Current 1983). As laboratory diagnostic techniques
improved during subsequent years, outbreaks among immunocompetent
persons were recognized as well. Human, cattle, dog and deer types of
C. parvum have been found in healthy individuals (Ong et al. 2002,
Morgan-Ryan et al. 2002). Other Cryptosporidium species (C. felis, C.
meleagridis, and possibly C. muris) have infected healthy individuals,
primarily children (Xiao et al. 2001, Chalmers et al. 2002, Katsumata
et al. 2000). Cross-species infection occurs. The human type of C.
parvum (now named C. hominis (Morgan-Ryan et al. 2002)) has infected a
dugong and monkeys (Spano et al. 1998). The cattle type of C. parvum
infects humans, wild animals, and other livestock, such as sheep, goats
and deer (Ong et al. 2002).
As noted earlier, there are sensitive populations that are at
greater risk from pathogenic microorganisms.

[[Page 47648]]

Cryptosporidiosis symptoms in immunocompromised subpopulations are much
more severe, including debilitating voluminous diarrhea that may be
accompanied by severe abdominal cramps, weight loss, and low grade
fever (Juranek 1995). Mortality is a significant threat to the
immunocompromised infected with Cryptosporidium:

the duration and severity of the disease are significant:
whereas 1 percent of the immunocompetent population may be
hospitalized with very little risk of mortality, Cryptosporidium
infections are associated with a high rate of mortality in the
immunocompromised (Rose 1997)

A follow-up study of the 1993 Milwaukee, WI outbreak reported that
at least 50 Cryptosporidium-associated deaths occurred among the
severely immunocompromised (Hoxie et al. 1997).
b. Waterborne cryptosporidiosis outbreaks. Cryptosporidium has
caused a number of waterborne disease outbreaks since 1984 when the
first one was reported in the U.S. Table II-1 lists reported outbreaks
in community water systems (CWS) and non-community water systems
(NCWS). Between 1984--1998, nine outbreaks caused by Cryptosporidium
were reported in the U.S. with approximately 421,000 cases associated
cases of illness (CDC 1993, 1996, 1998, 2000, and 2001). Solo-Gabriele
and Neumeister (1996) characterized water supplies associated with U.S.
outbreaks of cryptosporidiosis. They determined that almost half of the
outbreaks were associated with ground water (untreated or chlorinated
springs and wells), but that the majority of affected individuals were
served by filtered surface water supplies (rivers and lakes). They
found that during outbreaks involving treated spring or well water, the
chlorination systems were apparently operating satisfactorily, with a
measurable chlorine residual.
Although the occurrence of Cryptosporidium in U.S. drinking water
supplies has been substantiated by data collected during outbreak
investigations, the source and density of oocysts associated with the
outbreak have not always been detected or reported. Furthermore,
because of limitations and uncertainties of the immunofluorescence
assay (IFA) method used in earlier studies, negative results in source
or finished water during these outbreaks do not necessarily mean that
there were no oocysts in the water at the time of sampling.

Table II-1.--Outbreaks Caused by Cryptosporidium in Public Water Systems: 1984-1998
----------------------------------------------------------------------------------------------------------------
Year State Cases System Deficiency Source
----------------------------------------------------------------------------------------------------------------
1984......................... TX 117 CWS 3 Well.
1987......................... GA 13,000 CWS 3 River.
1991......................... PA 551 NCWS 3 Well.
1992......................... OR [dagger][da CWS 3 Spring.
gger]
1992......................... OR [dagger][da CWS 3 River.
gger]
1993......................... NV 103 CWS 5 Lake.
1993......................... WI 403,000 CWS 3 Lake.
1994......................... WA 134 CWS 2 Well.
1998......................... TX 1,400 CWS 3 Well.
----------------------------------------------------------------------------------------------------------------
[dagger][dagger] =Total estimated cases were 3,000. The locations were nearby and cases overlapped in time
Definitions of deficiencies = (1) untreated surface water; (2) untreated ground water; (3) treatment
deficiency (e.g., temporary interruption of disinfection, chronically inadequate disinfection, and inadequate
or no filtration); (4) distribution system deficiency (e.g., cross connection, contamination of water mains
during construction or repair, and contamination of a storage facility); and (5) unknown or miscellaneous
deficiency.

3. Remaining Public Health Concerns Following the IESWTR and LT1ESWTR
This section presents the areas of remaining public health concern
following implementation of the IESWTR and LT1ESWTR that EPA proposes
to address in the LT2ESWTR. These are as follows: (a) Adequacy of
physical removal to control Cryptosporidium and the need for risk based
treatment requirements; (b) control of Cryptosporidium in unfiltered
systems; and (c) uncovered finished water storage facilities.
EPA recognized each of these issues as a potential public health
concern during development of the IESWTR, but could not address them at
that time due to the absence of key data. Accordingly, this section
begins with a description of how EPA considered these issues during
development of the IESWTR, including the data gaps that were identified
at that time. This is followed by a statement of the extent to which
new information has filled these data gaps, thereby allowing EPA to
address these public health concerns in the LT2ESWTR proposal.
a. Adequacy of physical removal to control Cryptosporidium and the
need for risk based treatment requirements. A question that received
significant consideration during development of the IESWTR is whether
physical removal by filtration plants provides adequate protection
against Cryptosporidium in drinking water, or whether certain systems
should be required to provide inactivation of Cryptosporidium based on
source water pathogen levels. As discussed in the proposal, notice of
data availability (NODA), and final IESWTR, EPA and stakeholders
concluded that data available during IESWTR development were not
adequate to support risk based inactivation requirements for
Cryptosporidium. However, the Agency maintained that a risk based
approach to Cryptosporidium control would be considered for the
LT2ESWTR when data collected under the Information Collection Rule were
available and other critical information needs had been addressed.
The IESWTR proposal (59 FR 38832, July 29, 1994) (USEPA 1994)
included two treatment alternatives, labeled B and C, that specifically
addressed Cryptosporidium. Under Alternative B, the level of required
treatment would be based on the density of Cryptosporidium in the
source water. The proposal noted concerns with this approach, though,
due to uncertainty in the risk associated with Cryptosporidium and the
feasibility of achieving higher treatment levels through disinfection.
Consequently, EPA also proposed Alternative C, which would require 2
log (99%) removal of Cryptosporidium by filtration. This was based on
the determination that 2 log Cryptosporidium removal is feasible using
conventional treatment.
In the 1996 Information Collection Rule (61 FR 24354, May 14, 1996)
(USEPA 1996a), EPA concluded that the analytical method prescribed for
measuring Cryptosporidium was

[[Page 47649]]

adequate for making national occurrence estimates, but would not
suffice for making site specific source water density estimates. This
finding further contributed to the rationale supporting Alternative C
under the proposed IESWTR.
The NODA for the IESWTR (62 FR 59498, Nov. 3, 1997) (USEPA 1997a)
presented the recommendations of the Stage 1 MDBP Federal Advisory
Committee for the IESWTR. As stated in the NODA, the Committee engaged
in extensive discussions regarding the adequacy of relying solely on
physical removal to control Cryptosporidium and the need for
inactivation. There was an absence of consensus on whether it was
possible at that time to adequately measure Cryptosporidium
inactivation efficiencies for various disinfection technologies. This
was a significant impediment to addressing inactivation in the IESWTR.
However, the Committee recognized that inactivation requirements may be
necessary under future regulatory scenarios, as shown by the following
consensus recommendation from the Stage 1 MDBP Agreement in Principle:

EPA should issue a risk based proposal of the Final Enhanced
Surface Water Treatment Rule for Cryptosporidium embodying the
multiple barrier approach (e.g., source water protection, physical
removal, inactivation, etc.), including, where risks suggest
appropriate, inactivation requirements (62 FR 59557, Nov. 3, 1997)
(USEPA 1997a).

The preamble to the final IESWTR (63 FR 69478, Dec. 16, 1998)
(USEPA 1998a) states that EPA was unable to consider the proposed
Alternative B (treatment requirements for Cryptosporidium based on
source water occurrence levels) for the IESWTR because occurrence data
from the Information Collection Rule survey and related analysis were
not available in time to meet the statutory promulgation deadline. The
Agency affirmed, though, that further control of Cryptosporidium would
be addressed in the LT2ESWTR.
In today's notice, EPA is proposing a risk based approach for
control of Cryptosporidium in drinking water. Under this approach, the
required level of additional Cryptosporidium treatment relates to the
source water pathogen density. EPA believes many of the data gaps that
prevented the adoption of this approach under the IESWTR have been
addressed. As described in Section III of this preamble, information on
Cryptosporidium occurrence from the Information Collection Rule and
Information Collection Rule Supplemental Surveys, along with new data
on Cryptosporidium infectivity, have provided EPA with a better
understanding of the magnitude and distribution of risk for this
pathogen. Improved analytical methods allow for a more accurate
assessment of source water Cryptosporidium levels, and recent
disinfection studies with UV, ozone, and chlorine dioxide provide the
technical basis to support Cryptosporidium inactivation requirements.
b. Control of Cryptosporidium in unfiltered systems. There is
particular concern about Cryptosporidium in the source waters of
unfiltered systems because this pathogen has been shown to be resistant
to conventional disinfection practices. In the IESWTR, EPA extended
watershed control requirements for unfiltered systems to include the
control of Cryptosporidium. EPA did not establish Cryptosporidium
treatment requirements for unfiltered systems because available data
suggested an equivalency of risk in filtered and unfiltered systems.
This is described in the final IESWTR as follows:

it appears that unfiltered water systems that comply with the source
water requirements of the SWTR have a risk of cryptosporidiosis
equivalent to that of a water system with a well operated filter
plant using a water source of average quality (63 FR 69492, Dec. 16,
1998) (USEPA 1998a)

The Agency noted that data from the Information Collection Rule
would provide more information on Cryptosporidium levels in filtered
and unfiltered systems, and that Cryptosporidium treatment requirements
would be re-evaluated when these data became available.
In today's notice, EPA is proposing Cryptosporidium inactivation
requirements for unfiltered systems. These proposed requirements stem
from an assessment of Cryptosporidium source water occurrence in both
filtered and unfiltered systems using data from the Information
Collection Rule and other surveys, as described in Section III of this
preamble. These new data do not support the finding described in the
IESWTR of equivalent risk in filtered and unfiltered systems. Rather,
Cryptosporidium treatment by unfiltered systems is necessary to achieve
a finished water risk level equivalent to that of filtered systems. In
addition, the development of Cryptosporidium inactivation criteria for
UV, ozone, and chlorine dioxide in the LT2ESWTR has made it feasible
for unfiltered systems to provide Cryptosporidium treatment.
c. Uncovered finished water storage facilities. In the IESWTR
proposal, EPA solicited comment on a requirement that systems cover
finished water storage facilities to reduce the potential for
contamination by pathogens and hazardous chemicals. Potential sources
of contamination to uncovered storage facilities include airborne
chemicals, runoff, animal carcasses, animal or bird droppings, and
growth of algae and other aquatic organisms (59 FR 38832, July 29,
1994) (USEPA 1994).
The final IESWTR established a requirement to cover all new storage
facilities for finished water for which construction began after
February 16, 1999 (63 FR 69493, Dec. 16, 1998) (USEPA 1998a). In
preamble to the final IESWTR, EPA described future regulation of
existing uncovered finished water storage facilities as follows:

EPA needs more time to collect and analyze additional
information to evaluate regulatory impacts on systems with existing
uncovered reservoirs on a national basis . . . EPA will further
consider whether to require the covering of existing reservoirs
during the development of subsequent microbial regulations when
additional data and analysis to develop the national costs of
coverage are available.

EPA continues to be concerned about contamination resulting from
uncovered finished water storage facilities, particularly the potential
for virus contamination via bird droppings, and now has sufficient data
to estimate national cost implications for various regulatory control
strategies. Therefore, EPA is proposing control measures for all
systems with uncovered finished water storage facilities in the
LT2ESWTR. New data and proposed requirements are described in section
IV.E of this preamble.

D. Federal Advisory Committee Process

In March 1999, EPA reconvened the M-DBP Federal Advisory Committee
to develop recommendations for the Stage 2 DBPR and LT2ESWTR. The
Committee consisted of organizational members representing EPA, State
and local public health and regulatory agencies, local elected
officials, Indian Tribes, drinking water suppliers, chemical and
equipment manufacturers, and public interest groups. Technical support
for the Committee's discussions was provided by a technical workgroup
established by the Committee at its first meeting. The Committee's
activities resulted in the collection and evaluation of substantial new
information related to key elements for both rules. This included new
data on pathogenicity, occurrence, and treatment of microbial
contaminants, specifically including Cryptosporidium, as well as new
data on DBP health risks, exposure, and control. New information
relevant to the

[[Page 47650]]

LT2ESWTR is summarized in Section III of this proposal.
In September 2000, the Committee signed an Agreement in Principle
reflecting the consensus recommendations of the group. The Agreement
was published in a December 29, 2000 Federal Register notice (65 FR
83015, December 29, 2000) (USEPA 2000a). The Agreement is divided into
Parts A & B. The entire Committee reached consensus on Part A, which
contains provisions that directly apply to the Stage 2 DBPR and
LT2ESWTR. The full Committee, with the exception of one member, agreed
to Part B, which has recommendations for future activities by EPA in
the areas of distribution systems and microbial water quality criteria.
The Committee reached agreement on the following major issues
discussed in this notice and the proposed Stage 2 DBPR:
LT2ESWTR: (1) Additional Cryptosporidium treatment based on source
water monitoring results; (2) Filtered systems that must comply with
additional Cryptosporidium treatment requirements may choose from a
``toolbox'' of treatment and control options; (3) Reduced monitoring
burden for small systems; (4) Future monitoring to confirm source water
quality assessments; (5) Cryptosporidium inactivation by all unfiltered
systems; (6) Unfiltered systems meet overall inactivation requirements
using a minimum of 2 disinfectants; (7) Development of criteria and
guidance for UV disinfection and other toolbox options; (8) Cover or
treat existing uncovered finished water reservoirs (i.e., storage
facilities) or implement risk mitigation plans.
Stage 2 DBPR: (1) Compliance calculation for total trihanomethanes
(TTHM) and five haloacetic acids (HAA5) revised from a running annual
average (RAA) to a locational running annual average (LRAA); (2)
Compliance carried out in two phases of the rule; (3) Performance of an
Initial Distribution System Evaluation; (4) Continued importance of
simultaneous compliance with DBP and microbial regulations; (5)
Unchanged MCL for bromate.

III. New Information on Cryptosporidium Health Risks and Treatment

The purpose of this section is to describe information related to
health risks and treatment of Cryptosporidium in drinking water that
has become available since EPA developed the IESWTR. Much of this
information was evaluated by the Stage 2 M-DBP Federal Advisory
Committee when considering whether and to what degree existing
microbial standards should be revised to protect public health. It
serves as a basis for the recommendations made by the Advisory
Committee and for provisions in today's proposed rule. This section
begins with an overview of critical factors that EPA considers when
evaluating regulation of microbial pathogens. New information is then
presented on three key topics: Cryptosporidium infectivity, occurrence,
and treatment.

A. Overview of Critical Factors for Evaluating Regulation of Microbial
Pathogens

When proposing a national primary drinking water regulation that
includes a maximum contaminant level or treatment technique, SDWA
requires EPA to analyze the health risk reduction benefits and costs
likely to result from alternative regulatory levels that are being
considered. For assessing risk, EPA follows the paradigm described by
the National Academy of Science (NRC, 1983) which involves four steps:
(1) Hazard identification, (2) dose-response assessment, (3) exposure
assessment, and (4) risk characterization. The application of these
steps to microbial pathogens is briefly described in this section,
followed by a summary of how EPA estimates the health benefits and
costs of regulatory alternatives.
Hazard identification for microbial pathogens is a description of
the nature, severity, and duration of the health effects stemming from
infection. Under SDWA, EPA must consider health effects on the general
population and on subpopulations that are at greater risk of adverse
health effects. See section II.C.2 of this preamble for health effects
associated with Cryptosporidium.
Dose-response assessment with microorganisms is commonly termed
infectivity and is a description of the relationship between the number
of pathogens ingested and the probability of infection. Information on
Cryptosporidium infectivity is presented in section III.B of this
preamble.
Exposure to microbial pathogens in drinking water is generally a
function of the concentration of the pathogen in finished water and the
volume of water ingested (exposure also occurs through secondary routes
involving infected individuals). Because it is difficult to directly
measure pathogens at the low levels typically present in finished
water, EPA's information on pathogen exposure is primarily derived from
surveys of source water occurrence. EPA estimates the concentration of
pathogens in treated water by combining source water pathogen
occurrence data with information on the performance of treatment plants
in reducing pathogen levels. Data on the occurrence of Cryptosporidium
are described in section III.C of this preamble and in Occurrence and
Exposure Assessment for the LT2ESWTR (USEPA 2003b). Cryptosporidium
treatment studies are described in section III.D of this preamble.
Risk characterization is the culminating step of the risk
assessment process. It is a description of the nature and magnitude of
risk, and characterizes strengths, weaknesses, and attendant
uncertainties of the assessment. EPA's risk characterization for
Cryptosporidium is described in Economic Analysis for the LT2ESWTR
(USEPA 2003a).
Estimating the health benefits and costs that would result from a
new regulatory requirement involves a number of steps, including
evaluating the efficacy and cost of treatment strategies to reduce
exposure to the contaminant, forecasting the number of systems that
would implement different treatment strategies to comply with the
regulatory standard, and projecting the reduction in exposure to the
contaminant and consequent health risk reduction benefits stemming from
regulatory compliance. EPA's estimates of health benefits and costs
associated with the proposed LT2ESWTR are presented in Economic
Analysis for the LT2ESWTR (USEPA 2003a) and are summarized in section
VI of this preamble.

B. Cryptosporidium Infectivity

This section presents information on the infectivity of
Cryptosporidium oocysts. Infectivity relates the probability of
infection by Cryptosporidium with the number of oocysts that a person
ingests, and it is used to predict the disease burden associated with
different Cryptosporidium levels in drinking water. Information on
Cryptosporidium infectivity comes from dose-response studies where
healthy human subjects ingest different numbers of oocysts and are
subsequently evaluated for signs of infection and illness.
Data from a human dose-response study of one Cryptosporidium
isolate (the IOWA study, conducted at the University of Texas-Houston
Health Science Center) had been published prior to the IESWTR (DuPont
et al. 1995). Following IESWTR promulgation, a study of two additional
isolates (TAMU and UCP) was completed and published (Okhuysen et al.
1999). This study also presented a

[[Page 47651]]

reanalysis of the IOWA study results. As described in more detail later
in this section, this new study indicates that the infectivity of
Cryptosporidium oocysts varies over a wide range. The UCP oocysts
appeared less infective than those of the IOWA study while the TAMU
oocysts were much more infective. Although the occurrence of these
isolates among environmental oocysts is unknown, a meta-analysis of
these data conducted by EPA suggests the overall infectivity of
Cryptosporidium may be significantly greater than was estimated for the
IESWTR (USEPA 2003a).
This section begins with a description of the infectivity data
considered for the IESWTR. This is followed by a presentation of
additional data that have been evaluated for the proposed LT2ESWTR and
a characterization of the significance of these new data.
1. Cryptosporidium Infectivity Data Evaluated for IESWTR
Data from the IOWA study (DuPont et al. 1995) were evaluated for
the IESWTR. In that study, 29 individuals were given single doses
ranging from 30 oocysts to 1 million oocysts. This oocyst isolate was
originally obtained from a naturally infected calf. Seven persons
received doses above 500, and all were infected. Eleven of the twenty
two individuals receiving doses of 500 or fewer were classified as
infected based on oocysts detected in stool samples.
The IOWA study data were analyzed using an exponential dose-
response model established by Haas et al. (1996) for Cryptosporidium:

Probability {Infection / Dose{time} =
1-e ^-Dose/k
Based on the maximum likelihood estimate of k (238), the
probability of infection from ingesting a single oocyst (1/k) is
approximately 0.4% (4 persons infected for every 1,000 who each ingest
one oocyst). Based on the same estimate, the dose at which 50% of
persons become infected (known as the median infectious dose or ID50)
is 165.
2. New Data on Cryptosporidium Infectivity
A study of two additional Cryptosporidium isolates was conducted at
the University of Texas-Houston Health Science Center (Okhuysen et al.
1999). One of the isolates (UCP) was originally collected from
naturally infected calves. The other isolate (TAMU) was originally
collected from a veterinary student who became infected during necropsy
on an infected foal.
The TAMU and UCP studies were conducted with 14 and 17 subjects,
respectively. Because thousands of oocysts per gram of stool can go
undetected, researchers elected to use both stool test results and
symptoms as markers of infection (only stool test results had been used
for the IOWA study). Under this definition, two additional IOWA
subjects were regarded as having been infected. As shown in Table III-
1, all but two of the TAMU subjects were presumed infected and all but
six of the UCP subjects were presumed infected following ingestion of
the indicated oocyst doses.

Table III-1.--Cryptosporidium Parvum Infectivity in Healthy Adult
Volunteers
------------------------------------------------------------------------
Number of Number
Isolate and dose ( of oocysts) subjects infected
\1\ \1\
------------------------------------------------------------------------
IOWA:
30.......................................... 5 2
100......................................... 8 4
300......................................... 3 2
500......................................... 6 5
1,000....................................... 2 2
10,000...................................... 3 3
100,000..................................... 1 1
1,000,000................................... 1 1
TAMU:
10........................................ 3 2
30........................................ 3 2
100....................................... 3 3
500....................................... 5 5
UCP:
500....................................... 5 3
1,000..................................... 3 2
5,000..................................... 5 2
10,000.................................... 4 4
------------------------------------------------------------------------
\1\ The two right columns list the number of subjects belonging to each
category.

EPA conducted a meta-analysis of these results in which the three
isolates were considered as a random sample (of size three) from a
larger population of environmental oocysts (Messner et al. 2001). This
meta analysis was reviewed by the Science Advisory Board (SAB). In
written comments from a December 2001 meeting of the Drinking Water
Committee, SAB members recommended the following: (1) two assumed
infectivity distributions (of parameter r = 1/k as logit normal and
logit-t) should be used in order to characterize uncertainty and (2)
EPA should consider excluding the UCP data set because it seems to be
an outlier (see Section VII.K). In response, EPA has used the two
recommended distributions for infectivity and has conducted the meta-
analysis both with and without the UCP data due to uncertainty about
whether it is appropriate to exclude these data.
Table III-2 presents meta-analysis estimates of the probability of
infection given one oocyst ingested. Results are shown for the four
different analysis conditions (log normal and log-t distributions; with
and without UCP data) as well as a combined result derived by sampling
equally from each distribution. A more complete description of the
infectivity analysis is provided in Economic Analysis for the LT2ESWTR
(USEPA 2003a).

Table III-2.--Risk of Infection, Given One Oocyst Ingested
------------------------------------------------------------------------
Basis for analysis Probability of
----------------------------------------------- infection, one oocyst
ingested
-------------------------
Studies used Distributional 80%
model Mean Credible
interval
------------------------------------------------------------------------
IOWA, TAMU, and UCP.......... Normal......... 0.07 0.007-0.19
IOWA, TAMU, and UCP.......... Student's t 0.09 0.015-0.20
(3df) \1\.
IOWA and TAMU................ Normal......... 0.09 0.011-0.23
IOWA and TAMU................ Student's t 0.10 0.014-0.25
(3df) \1\.
--------------
Equal Mix of the Four ............... 0.09 0.011-0.22
Above.
------------------------------------------------------------------------
\1\ Student's t distribution with 3 degrees of freedom (3df).

[[Page 47652]]

The results in Table III-2 show that the mean probability of
infection from ingesting a single infectious oocyst ranges from 7% to
10% depending on the assumptions used. In comparison, the best estimate
in the IESWTR of this probability was 0.4%, based on the IOWA isolate
alone, and using the earlier definition of infection. Thus, these data
suggest that both the range and magnitude of Cryptosporidium
infectivity is higher than was estimated in the final IESWTR.
It should be noted that although significantly more data on
Cryptosporidium infectivity are available now than when EPA established
the IESWTR, there remains uncertainty about this parameter in several
areas. It is unknown how well the oocysts used in the feeding studies
represent Cryptosporidium naturally occurring in the environment, and
the analyses do not fully account for variability in host
susceptibility and the effect of previous infections. Furthermore, the
sample sizes are relatively small, and the confidence bands on the
estimates span more than an order of magnitude. Another limitation is
that none of the studies included doses below 10 oocysts, while when
people ingest oocysts in drinking water it is usually a single oocyst.
3. Significance of New Infectivity Data
The new infectivity data reveal that oocysts vary greatly in their
ability to infect human hosts. Moreover, due to this variability and
the finding of a highly infectious isolate, TAMU, the overall
population of oocysts appears to be more infective than assumed for the
IESWTR. The meta-analysis described earlier indicates the probability
of infection at low Cryptosporidium concentrations may be about 20
times as great as previously estimated (which was based on the IOWA
isolate alone and using the earlier definition of infection (stool-
confirmed infections)).

C. Cryptosporidium Occurrence

This section presents information on the occurrence of
Cryptosporidium oocysts in drinking water sources. Occurrence
information is important because it is used in assessing the risk
associated with Cryptosporidium in both filtered and unfiltered
systems, as well as in estimating the costs and benefits of the
proposed LT2ESWTR.
For the IESWTR, EPA had no national survey data and relied instead
on several studies that were local or regional. Those data suggested
that a typical (median) filtered surface water source had approximately
2 Cryptosporidium oocysts per liter, while a typical unfiltered surface
water source had about 0.01 oocysts per liter, a difference of two
orders of magnitude.
Subsequent to promulgating the IESWTR, EPA obtained data from two
national surveys: the Information Collection Rule and the Information
Collection Rule Supplemental Surveys (ICRSS). These surveys were
designed to provide improved estimates of occurrence on a national
basis. As described in more detail later in this section, the
Information Collection Rule and ICRSS results show three main
differences in comparison to Cryptosporidium occurrence data used for
the IESWTR:

(1) Average Cryptosporidium occurrence is lower. Median oocyst
levels for the Information Collection Rule and ICRSS data are
approximately 0.05/L, which is more than an order of magnitude lower
than IESWTR estimates.
(2) Cryptosporidium occurrence is more variable from location to
location than was shown by the data considered for the IESWTR. This
indicates that although median occurrence levels are below those
assumed for the IESWTR, there is a subset of systems whose levels
are considerably greater than the median.
(3) There is a smaller difference in Cryptosporidium levels
between typical filtered and unfiltered system water sources. The
Information Collection Rule data do not support the IESWTR finding
that unfiltered water systems have a risk of cryptosporidiosis
equivalent to that of a filter plant with average quality source
water.

This section begins with a summary of occurrence data that were
used to assess risk under the IESWTR (these data were also used in the
main risk assessment for the LT1ESWTR). This is followed by a
discussion of the Information Collection Rule and ICRSS that covers the
scope of the surveys, analytical methods, results, and a
characterization of how these new data impact current understanding of
Cryptosporidium exposure. A more detailed description of occurrence
data is available in Occurrence and Exposure Assessment for the Long
Term 2 Enhanced Surface Water Treatment Rule (USEPA 2003b).
1. Occurrence Data Evaluated for IESWTR
Occurrence information evaluated for the IESWTR is detailed in
Occurrence and Exposure Assessment for The Interim Enhanced Surface
Water Treatment Rule (USEPA 1998c). This information is summarized in
the next two paragraphs.
a. Filtered systems. In developing the IESWTR, EPA evaluated
Cryptosporidium occurrence data from a number of studies. Among these
studies, LeChevallier and Norton (1995) produced the largest data set
and data from this study were used for the IESWTR risk assessment. This
study provided estimates of mean occurrence at 69 locations from the
eastern and central U.S. Although limited by the small number of
samples per site (one to sixteen samples; most sites were sampled five
times), variation within and between sites appeared to be lognormal.
The study's median measured source water concentration was 2.31
oocysts/L and the interquartile range (i.e., 25th and 75th percentile)
was 1.03 to 5.15 oocysts/L.
b. Unfiltered systems. To assess Cryptosporidium occurrence in
unfiltered systems under the IESWTR, EPA evaluated Cryptosporidium
monitoring results from several unfiltered water systems that had been
summarized by the Seattle Water Department (Montgomery Watson, 1995).
The median (central tendency) of these data was approximately 0.01
oocysts/L. Thus, the median concentration in these data set was about 2
orders of magnitude less than the median concentration in the data set
used for filtered systems. These data, coupled with the assumption that
filtered systems will remove at least 2 log of Cryptosporidium as
required by the IESWTR, suggested that unfiltered systems that comply
with the source water requirements of the SWTR may have a risk of
cryptosporidiosis equivalent to that of a filter plant using a water
source of average quality (62 FR 59507, November 3, 1997) (USEPA
1997a).
2. Overview of the Information Collection Rule and Information
Collection Rule Supplemental Surveys (ICRSS)
The Information Collection Rule and the Information Collection Rule
Supplemental Surveys (ICRSS) were national monitoring studies. They
were designed to provide EPA with a more comprehensive understanding of
the occurrence of microbial pathogens in drinking water sources in
order to support regulatory decision making. The surveys attempted to
control protozoa measurement error through requiring that (1)
laboratories meet certain qualification criteria, (2) standardized
methods be used to collect data, and (3) laboratories analyze
performance evaluation samples throughout the duration of the study to
ensure adequate analytical performance. Information Collection Rule
monitoring took place from July 1997 to December 1998; ICRSS
Cryptosporidium monitoring

[[Page 47653]]

began in March 1999 and ended in February 2000.
a. Scope of the Information Collection Rule. The Information
Collection Rule (61 FR 24354, May 14, 1996) (USEPA 1996a) required
large PWSs to collect water quality and treatment data related to DBPs
and microbial pathogens over an 18-month period. PWSs using surface
water or ground water under the direct influence of surface water as
sources and serving at least 100,000 people were required to monitor
their raw water monthly for Cryptosporidium, Giardia, viruses, total
coliforms, and E. coli. Approximately 350 plants monitored for
microbial parameters.
b. Scope of the ICRSS. The ICRSS were designed to complement the
Information Collection Rule data set with data from systems serving
fewer than 100,000 people and by employing an improved analytical
method for protozoa (described later). The ICRSS included 47 large
systems (serving greater than 100,000 people), 40 medium systems
(serving 10,000 to 100,000 people) and 39 small systems (serving fewer
than 10,000 people). Medium and large systems conducted 1 year of
twice-per-month sampling for Cryptosporidium, Giardia , temperature,
pH, turbidity, and coliforms. Other water quality measurements were
taken once a month. Small systems did not test for protozoa but tested
for all other water quality parameters.
3. Analytical Methods for Protozoa in the Information Collection Rule
and ICRSS
This subsection describes analytical methods for Cryptosporidium
that were used in the Information Collection Rule and ICRSS.
Information on Cryptosporidium analytical methods is important for the
LT2ESWTR for several reasons: (1) It is relevant to the quality of
Cryptosporidium occurrence data used to assess risk and economic impact
of the LT2ESWTR proposal, (2) it provides a basis for the statistical
procedures employed to analyze the occurrence data, and (3) it is used
to assess the adequacy of Cryptosporidium methods to support source-
specific decisions under the LT2ESWTR.
The Information Collection Rule and ICRSS data sets were generated
using different analytical methods. The Information Collection Rule
Protozoan Method (ICR Method) was used to analyze water samples for
Cryptosporidium during the Information Collection Rule. For the ICRSS,
a similar but improved method, EPA Method 1622 (later 1623), was used
for protozoa analyses (samples were analyzed for Cryptosporidium using
Method 1622 for the first 4 months; then Method 1623 was implemented so
that Giardia concentrations could also be measured).
a. Information Collection Rule Protozoan Method. With the
Information Collection Rule Method (USEPA 1996b), samples were
collected by passing water through a filter, which was then delivered
to an EPA-approved Information Collection Rule laboratory for analysis.
The laboratory eluted the filter, centrifuged the eluate, and separated
Cryptosporidium oocysts and Giardia cysts from other debris by density-
gradient centrifugation. The oocysts and cysts were then stained and
counted. Differential interference contrast (DIC) microscopy was used
to examine internal structures.
The Information Collection Rule Method provided a quantitative
measurement of Cryptosporidium oocysts and Giardia cysts, but it is
believed to have generally undercounted the actual occurrence
(modeling, described later, adjusted for undercounting). This
undercounting was due to low volumes analyzed and low method recovery.
The volume analyzed directly influences the sensitivity of the
analytical method and the Information Collection Rule Method did not
require a specific volume analyzed. As a result, sample volumes
analyzed during the Information Collection Rule varied widely,
depending on the water matrix and analyst discretion, with a median
volume analyzed of only 3 L.
Method recovery characterizes the likelihood that an oocyst present
in the original sample will be counted. Loss of organisms may occur at
any step of the analytical process, including filtration, elution,
concentration of the eluate, and purification of the concentrate. To
assess the performance of the Information Collection Rule Method, EPA
implemented the Information Collection Rule Laboratory Spiking Program.
This program involved collection of duplicate samples on two dates from
70 plants. On each occasion, one of the duplicate samples was spiked
with a known quantity of Giardia cysts and Cryptosporidium oocysts (the
quantity was unknown to the laboratory performing the analysis), and
both samples were processed according to the method. Recovery of spiked
Cryptosporidium oocysts ranged from 0% to 65% with a mean of 12% and a
standard deviation nearly equal to the mean (relative standard
deviation (RSD) approximately 100%) (Scheller et al. 2002).
b. Method 1622 and Method 1623. EPA developed Method 1622 (detects
Cryptosporidium) and 1623 (detects Cryptosporidium and Giardia) to
achieve higher recovery rates and lower inter- and intra-laboratory
variability than previous methods. These methods incorporate
improvements in the concentration, separation, staining, and microscope
examination procedures. Specific improvements include the use of more
effective filters, immunomagnetic separation (IMS) to separate the
oocysts and cysts from extraneous materials present in the water
sample, and the addition of 4, 6-diamidino-2-phenylindole (DAPI) stain
for microscopic analysis. The performance of these methods was tested
through single-laboratory studies and validated through multiple-
laboratory validation (round robin) studies.
The per-sample volume analyzed for Cryptosporidium during the ICRSS
was larger than in the Information Collection Rule, due to a
requirement that laboratories analyze a minimum of 10 L or 2 mL of
packed pellet with Methods 1622/23 (details in section IV.K). To assess
method recovery, matrix spike samples were analyzed on five sampling
events for each plant. The protozoa laboratory spiked the additional
sample with a known quantity of Cryptosporidium oocysts and Giardia
cysts (the quantity was unknown to the laboratory performing the
analysis) and filtered and analyzed both samples using Methods 1622/23.
Recovery in the ICRSS matrix spike study averaged 43% for
Cryptosporidium with an RSD of 47% (Connell et al. 2000). Thus, mean
Cryptosporidium recovery with Methods 1622/23 under the ICRSS was more
than 3.5 times higher than mean recovery in the Information Collection
Rule lab spiking program and relative standard deviation was reduced by
more than half.
Although Methods 1622 and 1623 have several advantages over the
Information Collection Rule method, they also have some of the same
limitations. These methods do not determine whether a cyst or oocyst is
viable and infectious, and both methods require a skilled microscopist
and several hours of sample preparation and analyses.
4. Cryptosporidium Occurrence Results from the Information Collection
Rule and ICRSS
This section describes Cryptosporidium monitoring results from the
Information Collection Rule and ICRSS. The focus of this discussion is
the national distribution of mean Cryptosporidium occurrence levels in
the sources of filtered and unfiltered plants.

[[Page 47654]]

The observed (raw, unadjusted) Cryptosporidium data from the
Information Collection Rule and ICRSS do not accurately characterize
true concentrations because of (a) the low and variable recovery of the
analytical method, (b) the small volumes analyzed, and (c) the
relatively small number of sample events. EPA employed a statistical
treatment to estimate the true underlying occurrence that led to the
data observed in the surveys and to place uncertainty bounds about that
estimation.
A hierarchical model with Bayesian parameter estimation techniques
was used to separately analyze filtered and unfiltered system data from
the Information Collection Rule and the large and medium system data
from the ICRSS. The model included parameters for location, month,
source water type, and turbidity. Markov Chain Monte Carlo methods were
used to estimate these parameters, producing a large number of estimate
sets that represent uncertainty. This analysis is described more
completely in Occurrence and Exposure Assessment for the Long Term 2
Enhanced Surface Water Treatment Rule (USEPA 2003b).
a. Information Collection Rule results. Figure III-1 presents
plant-mean Cryptosporidium levels for Information Collection Rule
plants as a cumulative distribution. Included in Figure III-1 are
distributions of both the observed raw data adjusted for mean
analytical method recovery of 12% and the modeled estimate of the
underlying distribution, along with 90% confidence bounds. The two
distributions (observed and modeled) are similar for plants where
Cryptosporidium was detected (196 of 350 Information Collection Rule
plants did not detect Cryptosporidium in any source water samples). The
modeled distribution allows for estimation of Cryptosporidium
concentrations in sources where oocysts may have been present but were
not detected due to low sample volume and poor method recovery (this
concept is explained further later in this section).
BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TP11AU03.000

BILLING CODE 6560-50-P
The results shown in Figure III-1 indicate that mean
Cryptosporidium levels among Information Collection Rule plants vary
widely, with many plants having relatively little contamination and a
fraction of plants with elevated source water pathogen levels. The
median and 90th percentile estimates of Information Collection Rule
plant-mean Cryptosporidium levels are 0.048 and 1.3 oocysts/L,
respectively. These levels are lower than Cryptosporidium occurrence
estimates used in the IESWTR (USEPA 1998c), and the distribution of
Information

[[Page 47655]]

Collection Rule data is broader (i.e., more source-to-source
variability). Also, the occurrence of Cryptosporidium in flowing stream
sources was greater and more variable than in reservoir/lake sources
(shown in USEPA 2003b).
The fact that only 44% of Information Collection Rule plants had
one or more samples positive for Cryptosporidium and that only 7% of
all Information Collection Rule samples were positive for
Cryptosporidium suggests that oocyst levels were relatively low in many
source waters. However, as noted earlier, it is expected that
Cryptosporidium oocysts were present in many more source waters at the
time of sampling and were not detected due to poor analytical method
recovery and low sample volumes.
This concept is illustrated by Figure III-2, which shows the
likelihood of no oocysts being detected by the Information Collection
Rule method as a function of source water concentration (assumes median
Information Collection Rule sample volume of 3 L). As can be seen in
Figure III-2, when the source water concentration is 1 oocyst/L, which
is a relatively high level, the probability of no oocysts being
detected in a 3 L sample is 73%; for a source water with 0.1 oocyst/L,
which is close to the median occurrence level, the probability of a
non-detect is 97%. Consequently, EPA has concluded that it is
appropriate and necessary to use a statistical model to estimate the
underlying distribution.
EPA modeled Cryptosporidium occurrence separately for filtered and
unfiltered plants that participated in the Information Collection Rule
because unfiltered plants comply with different regulatory requirements
than filtered plants. As shown in Table III-3, the occurrence of
Cryptosporidium was lower for unfiltered sources.
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Table III-3.--Summary of Information Collection Rule Cryptosporidium
Modeled Source Water Data for Unfiltered and Filtered Plants
------------------------------------------------------------------------
Information collection rule
modeled plant-mean (oocysts/
L)
Source ----------------------------
90th
Mean Median percentile
------------------------------------------------------------------------
Unfiltered................................. 0.014 0.0079 0.033
Filtered................................... 0.59 0.052 1.4
------------------------------------------------------------------------

The median Cryptosporidium occurrence level for unfiltered systems
in the Information Collection Rule was 0.0079 oocysts/L, which is close
to the median level of 0.01 oocysts/L reported for unfiltered systems
in the IESWTR (Montgomery Watson, 1995). However, the Information
Collection Rule data do not show the 2 log difference in median
Cryptosporidium levels between filtered and unfiltered systems that was
observed for the data used in the IESWTR. The ratio of median plant-
mean occurrence in unfiltered plants to filtered plants is about 1:7
(see Table III-3). Thus, based on an assumption of a minimum 2 log
removal of Cryptosporidium by filtration plants (as required by the
IESWTR and LT1ESWTR), these data indicate that, on average, finished
water oocysts levels are higher in unfiltered systems than in filtered
systems.
b. ICRSS results. Figures III-3 and III-4 present plant-mean
Cryptosporidium levels for ICRSS medium and large systems,
respectively, as cumulative distributions. Medium and large system data
were analyzed separately to identify differences between the two data
sets. Similar to the Information Collection Rule data plot, Figures
III-3 and III-4 include distributions for both the observed raw data
adjusted for mean analytical method recovery of 43% and the modeled
estimate of the underlying distribution, along with 90% confidence
bounds. The observed and modeled distributions are similar for the 85%
of ICRSS plants that detected Cryptosporidium, and the modeled
distribution allows for estimation of Cryptosporidium concentrations
for source waters where oocysts may have been present but were not
detected.
Plant-mean Cryptosporidium concentrations for large and medium
systems in the ICRSS are similar at the mid and lower range of the
distribution and differ at the upper end. ICRSS medium and large
systems both had median plant-mean Cryptosporidium levels of
approximately 0.05 oocysts/L, which is close to the median oocyst level
in the Information Collection Rule data set as well. However, the 90th
percentile plant-mean was 0.33 oocysts/L for ICRSS medium systems and
0.24 oocysts/L for ICRSS large systems. Note that in the Information
Collection Rule distribution, the 90th percentile Cryptosporidium
concentration is 1.3 oocysts/L, which is significantly higher than
either the ICRSS medium or large system distribution.
The reasons for different results between the surveys are not well
understood, but may stem from year-to-year variation in occurrence,
systematic differences in the sampling or measurement methods employed,
and differences in the populations sampled. This topic is discussed
further at the end of this section.
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5. Significance of new Cryptosporidium occurrence data.
The Information Collection Rule and ICRSS data substantially
improve overall knowledge of the occurrence distribution of
Cryptosporidium in drinking water sources. They provide data on many
more water sources than were available when the IESWTR was developed
and the data are of more uniform quality. In regard to filtered
systems, these new data demonstrate two points:

(1) The occurrence of Cryptosporidium in many drinking water
sources is lower than was indicated by the data used in IESWTR.
Median plant-mean levels for the Information Collection Rule and
ICRSS data sets are approximately 0.05 oocysts/L, whereas the median
oocyst concentration in the LeChevallier and Norton (1995) data used
in the IESWTR risk assessment was 2.3 oocysts/L.
(2) Cryptosporidium occurrence is more variable from plant to
plant than was indicated by the data considered for the IESWTR
(i.e., occurrence distribution is broader). This is illustrated by
considering the ratio of the 90th percentile to the median plant-
mean concentration. In the LeChevallier and Norton (1995) data used
for the IESWTR, this ratio was 4.6, whereas in the Information
Collection Rule data, this ratio is 27.

These data, therefore, support the finding that Cryptosporidium
levels are relatively low in most water sources, but there is a subset
of sources with relatively higher concentrations where additional
treatment may be appropriate.
In regard to unfiltered plants, the Information Collection Rule
data are consistent with the Cryptosporidium occurrence estimates for
unfiltered systems in the IESWTR. However, due to the lower occurrence
estimates for filtered systems noted previously, the Information
Collection Rule data do not support the IESWTR finding that unfiltered
water systems in compliance with the source water requirements of the
SWTR have a risk of cryptosporidiosis equivalent to that of a well-
operated filter plant using a water source of average quality (63 FR
69492, December 16, 1998) (USEPA 1998a). Rather, these data indicate
that Agency conclusions regarding the risk comparison between
unfiltered and filtered drinking waters must be revised. For protection
equivalent to that provided by filtered systems, unfiltered systems
must take additional steps to strengthen their microbial barriers.
6. Request for Comment on Information Collection Rule and ICRSS Data
Sets
EPA notes that there are significant differences in the Information
Collection Rule and ICRSS medium and large system data sets. The median
values for these data sets are 0.048, 0.050, and 0.045 oocysts/L,
respectively, while the 90th percentile values are 1.3, 0.33, and 0.24
oocysts/L. The reasons for these differences are not readily apparent.
The ICRSS used a newer method with better quality control that yields
significantly higher recovery, and this suggests that these data are
more

[[Page 47659]]

reliable for estimating concentrations at individual plants. However,
the Information Collection Rule included a much larger number of plants
(350 v. 40 each for the ICRSS medium and large system surveys) and,
consequently, may be more reliable for estimating occurrence
nationally. The surveys included a similar number of samples per plant
(18 v. 24 in the ICRSS). The two surveys cover different time periods
(7/97-12/98 for the Information Collection Rule and 3/99-2/00 for the
ICRSS).
In order to better understand the factors that may account for the
differences in the three data sets, EPA conducted several additional
analyses. First, EPA compared results for the subset of 40 plants that
were in both the Information Collection Rule and ICRSS large system
surveys. The medians for the two data sets were 0.13 and 0.045 oocysts/
L, respectively, while the 90th percentiles were 1.5 and 0.24 oocysts/
L. Clearly, the discrepancy between the two surveys persists for the
subsample of data from plants that participated in both surveys. This
suggests that the different sample groups in the full data sets are not
the primary factor that accounts for the different results.
Next, EPA looked at the six month period (July through December)
that was sampled in two consecutive years (1997 and 1998) during the
Information Collection Rule survey to investigate year-to-year
variations at the same plants. Estimated medians for 1997 and 1998 were
0.062 and 0.040 oocysts/L, respectively, while the 90th percentiles
were 1.1 and 1.3 oocysts/L. While these comparisons show some interyear
variability, it is less than the variability observed between the
Information Collection Rule and ICRSS data sets. EPA has no data
comparing the same plants using the same methods for the time periods
in question (1997-98 and 1999-2000) so it is not known if the variation
between these time periods was larger than the apparent variation
between 1997 and 1998 in the Information Collection Rule data set.
The choice of data set has a significant effect on exposure, cost,
and benefit estimates for the LT2ESWTR. Due to the lack of any clear
criterion for favoring one data set over the other, EPA has conducted
the analyses for this proposed rule separately for each, and presents a
range of estimates based on the three data sets. EPA requests comment
on this approach. EPA will continue to evaluate the relative strengths
and limitations of the three data sets, as well as any new data that
may become available for the final rule.

D. Treatment

1. Overview
This section presents information on treatment processes for
reducing the risk from Cryptosporidium in drinking water. Treatment
information is critical to two aspects of the LT2ESWTR: (1) estimates
of the efficiency of water filtration plants in removing
Cryptosporidium are used in assessing risk in treated drinking water
and (2) the performance and availability of treatment technologies like
ozone, UV light, and membranes that effectively inactivate or remove
Cryptosporidium impact the feasibility of requiring additional
treatment for this pathogen.
The majority of plants treating surface water use conventional
filtration treatment, which is defined in 40 CFR 141.2 as a series of
processes including coagulation, flocculation, sedimentation, and
filtration. Direct filtration, which is typically used on sources with
low particulate levels, includes coagulation and filtration but not
sedimentation. Other common filtration processes are slow sand,
diatomaceous earth (DE), membranes, and bag and cartridge filters.
For the IESWTR (and later the LT1ESWTR), EPA evaluated results from
pilot and full scale studies of Cryptosporidium removal by various
types of filtration plants. Based on these studies, EPA concluded that
conventional and direct filtration plants meeting IESWTR filter
effluent turbidity standards will achieve a minimum 2 log (99%) removal
of Cryptosporidium. The Agency reached the same conclusion for slow
sand and DE filtration plants meeting SWTR turbidity standards.
Treatment credit for technologies like membranes and bag and cartridge
filters was to be made on a product-specific basis.
Subsequent to promulgating the IESWTR and LT1ESWTR, EPA has
reviewed additional studies of the performance of treatment plants in
removing Cryptosporidium, as well as other micron size particles (e.g.,
aerobic spores) that may serve as indicators of Cryptosporidium
removal. As discussed later in this section, the Agency has concluded
that these studies support an estimate of 3 log (99.9%) for the average
Cryptosporidium removal efficiency of conventional treatment plants in
compliance with the IESWTR or LT1ESWTR. Section IV.A describes how this
estimate of average removal efficiency is used in determining the need
for additional Cryptosporidium treatment under the LT2ESWTR. Further,
this estimate is consistent with the Stage 2 M-DBP Agreement in
Principle, which states as follows:

The additional treatment requirements in the (LT2ESWTR) bin
requirement table are based, in part, on the assumption that
conventional treatment plants in compliance with the IESWTR achieve
an average of 3 logs removal of Cryptosporidium.

In addition, the Agency finds that available data support an
estimate of 3 log average Cryptosporidium removal for well operated
slow sand and DE plants. Direct filtration plants are estimated to
achieve a 2.5 log average Cryptosporidium reduction, in consideration
of the absence of a sedimentation process in these plants.
The most significant developments in the treatment of
Cryptosporidium since IESWTR promulgation are in the area of
inactivation. During IESWTR development, EPA determined that available
data were not sufficient to identify criteria for awarding
Cryptosporidium treatment credit for any disinfectant. As presented in
section IV.C.14, EPA has now acquired the necessary data to specify the
disinfectant concentrations and contact times necessary to achieve
different levels of Cryptosporidium inactivation with chlorine dioxide
and ozone. Additionally, recent studies have demonstrated that UV light
will produce high levels of Cryptosporidium and Giardia lamblia
inactivation at low doses. Section IV.C.15 provides criteria for
systems to achieve credit for disinfection of Cryptosporidium, Giardia
lamblia, and viruses by UV.
This section begins with a summary of treatment information
considered for the IESWTR and LT1ESWTR, followed by a discussion of
additional data that EPA has evaluated since promulgating those
regulations. Further information on treatment of Cryptosporidium is
available in Technologies and Costs for Control of Microbial
Contaminants and Disinfection Byproducts (USEPA 2003c), Occurrence and
Exposure Assessment for the Long Term 2 Enhanced Surface Water
Treatment Rule (USEPA 2003b) and section IV.C of this preamble.
2. Treatment information considered for the IESWTR and LT1ESWTR
Treatment studies that were evaluated during development of the
IESWTR are described in the IESWTR NODA (62 FR 59486, November 3, 1997)
(USEPA 1997b), the Regulatory Impact Analysis for the IESWTR (USEPA
1998d), and Technologies and Costs for the Microbial Recommendations of
the M/DBP Advisory Committee (USEPA 1997b). Treatment information
considered in development of the

[[Page 47660]]

LT1ESWTR is described in the proposed rule (65 FR 59486, April 10,
2000) (USEPA 2000b). Pertinent information is summarized in the
following paragraphs.
a. Physical removal. EPA evaluated eight studies on removal of
Cryptosporidium by rapid granular filtration for the IESWTR. These were
Patania et al. (1995), Nieminski and Ongerth (1995), Ongerth and
Pecoraro (1995), LeChevallier and Norton (1992), LeChevallier et al.
(1991), Foundation for Water Research (1994), Kelley et al. (1995), and
West et al. (1994). These studies included both pilot and full scale
plants.
Full scale plants in these studies typically demonstrated 2-3 log
removal of Cryptosporidium, and pilot plants achieved up to almost 6
log removal under optimized conditions. In general, the degree of
removal that can be quantified in full scale plants is limited because
Cryptosporidium levels following filtration are often below the
detection limit of the analytical method. Pilot scale studies overcome
this limitation by seeding high concentrations of oocysts to the plant
influent, but extrapolation of the performance of a pilot plant to the
routine performance of full scale plants is uncertain.
Cryptosporidium removal efficiency in these studies was observed to
depend on a number of factors including: water matrix, coagulant
application, treatment optimization, filtered water turbidity, and the
filtration cycle. The highest removal rates were observed in plants
that achieved very low effluent turbidities.
EPA also evaluated studies of Cryptosporidium removal by slow sand
(Schuler and Ghosh 1991, Timms et al. 1995) and DE filtration (Schuler
and Gosh 1990) for the IESWTR. These studies indicated that a well
designed and operated plant using these processes could achieve 3 log
or greater removal of Cryptosporidium.
After considering these studies, EPA concluded that conventional
and direct filtration plants in compliance with the effluent turbidity
criteria of the IESWTR, and slow sand and DE plants in compliance with
the effluent turbidity criteria established for these processes by the
SWTR, would achieve at least 2 log removal of Cryptosporidium.
Recognizing that many plants will achieve more than the minimum 2 log
reduction, EPA estimated median Cryptosporidium removal among
filtration plants as near 3 log (99.9%) for the purpose of assessing
risk.
The LT1ESWTR proposal included summaries of additional studies of
Cryptosporidium removal by conventional treatment (Dugan et al. 1999),
direct filtration (Swertfeger et al. 1998), and DE filtration (Ongerth
and Hutton 1997). These studies supported IESWTR conclusions stated
previously regarding the performance of these processes. The LT1ESWTR
proposal also summarized studies of membranes, bag filters, and
cartridge filters (Jacangelo et al. 1995, Drozd and Schartzbrod 1997,
Hirata and Hashimoto 1998, Goodrich et al. 1995, Collins et al. 1996,
Lykins et al. 1994, Adham et al. 1998). This research demonstrated that
these technologies may be capable of achieving 2 log or greater removal
of Cryptosporidium. However, EPA concluded that variation in
performance among different manufacturers and models necessitates that
determinations of treatment credit be made on a technology-specific
basis (65 FR 19065, April 10, 2000) (USEPA 2000b).
b. Inactivation. In the IESWTR NODA (62 FR 59486) (USEPA 1997a),
EPA cited studies that demonstrated that chlorine is ineffective for
inactivation of Cryptosporidium at doses practical for treatment plants
(Korich et al. 1990, Ransome et al. 1993, Finch et al. 1997). The
Agency also summarized studies of Cryptosporidium inactivation by UV,
ozone, and chlorine dioxide. EPA evaluated these disinfectants to
determine if sufficient data were available to develop prescriptive
disinfection criteria for Cryptosporidium.
The studies of UV disinfection of Cryptosporidium that were
available during IESWTR development were inconclusive due to
methodological factors. These studies included: Lorenzo-Lorenzo et al.
(1993), Ransome et al. (1993), Campbell et al. (1995), Finch et al.
(1997), and Clancy et al. (1997). A common limitation among these
studies was the use of in vitro assays, such as excystation and vital
dye staining, to measure loss of infectivity. These assays subsequently
were shown to overestimate the UV dose needed to inactivate protozoa
(Clancy et al. 1998, Craik et al. 2000). In another case, a reactor
vessel that blocked germicidal light was used (Finch et al. 1997).
EPA evaluated the following studies of ozone inactivation of
Cryptosporidium for the IESWTR: Peeters et al. (1989), Korich et al.
(1990), Parker et al. (1993), Ransome et al. (1993), Finch et al.
(1997), Daniel et al. (1993), and Miltner et al. (1997). These studies
demonstrated that ozone could achieve high levels of Cryptosporidium
inactivation, albeit at doses much higher than those required to
inactivate Giardia. Results of these studies also exhibited significant
variability due to factors like different infectivity assays and
methods of dose calculation.
The status of chlorine dioxide inactivation of Cryptosporidium
during IESWTR development was similar to that of ozone. EPA evaluated a
number of studies that indicated that relatively high doses of chlorine
dioxide could achieve significant inactivation of Cryptosporidium
(Peeters et al. 1989, Korich et al. 1990, Ransome et al. 1993, Finch et
al. 1995 and 1997, and LeChevallier et al. 1997). Data from these
studies showed a high level of variability due to methodological
differences, and the feasibility of high chlorine dioxide doses was
uncertain due to the MCL for chlorite that was established by the Stage
1 DBPR.
After reviewing these studies, EPA and the Stage 1 Federal Advisory
Committee concluded that available data were not adequate to award
Cryptosporidium inactivation credit for UV, ozone, or chlorine dioxide.
3. New Information on Treatment for Control of Cryptosporidium
a. Conventional filtration treatment and direct filtration. This
section provides brief descriptions of seven recent studies of
Cryptosporidium removal by conventional treatment and direct
filtration, followed by a summary of key points.
Dugan et al. (2001) evaluated the ability of conventional treatment
to control Cryptosporidium under varying water quality and treatment
conditions, and assessed turbidity, total particle counts (TPC), and
aerobic endospores as indicators of Cryptosporidium removal. Fourteen
runs were conducted on a small pilot scale plant that had been
determined to provide equivalent performance to a larger plant. Under
optimal coagulation conditions, oocyst removal across the sedimentation
basin ranged from 0.6 to 1.8 log, averaging 1.3 log, and removal across
the filters ranged from 2.9 to greater than 4.4 log, averaging greater
than 3.7 log. Removal of aerobic spores, TPC, and turbidity all
correlated with removal of Cryptosporidium by sedimentation, and these
parameters were conservative indicators of Cryptosporidium removal
across filtration. Sedimentation removal under optimal conditions
related to raw water quality, with the lowest Cryptosporidium removals
observed when raw water turbidity was low.
Suboptimal coagulation conditions (underdosed relative to jar test
predictions) significantly reduced plant

[[Page 47661]]

performance. Oocyst removal in the sedimentation basin averaged 0.2
log, and removal by filtration averaged 1.5 log. Under suboptimal
coagulation conditions, low sedimentation removals of Cryptosporidium
were observed regardless of raw water turbidity.
Nieminski and Bellamy (2000) investigated surrogates as indicators
of Giardia and Cryptosporidium in source water and as measures of
treatment plant effectiveness. It involved sampling for microbial
pathogens (Giardia, Cryptosporidium, and enteric viruses), potential
surrogates (bacteria, bacteria spores, bacterial phages, turbidity,
particles), and other water quality parameters in the source and
finished waters of 23 surface water filtration facilities and one
unfiltered system.
While Giardia and Cryptosporidium were found in the majority of
source water samples, the investigators could not establish a
correlation between either occurrence or removal of these protozoa and
any of the surrogates tested. This was attributed, in part, to low
concentrations of Giardia and Cryptosporidium in raw water and high
analytical method detection limits. Removal of Cryptosporidium and
Giardia averaged 2.2 and 2.6 log, respectively, when conservatively
estimated using detection limits in filtered water. Aerobic spores were
found in 85% of filtered water samples and were considered a measure of
general treatment effectiveness. Average reduction of aerobic spores
was 2.84 log. Direct filtration plants removed fewer aerobic spores
than conventional or softening plants.
McTigue et al. (1998) conducted an on-site survey of 100 treatment
plants for particle counts, pathogens (Cryptosporidium and Giardia),
and operational information. The authors also performed pilot scale
spiking studies. Median removal of particles greater than 2 mm was 2.8
log, with values ranging from 0.04 to 5.5 log. Removal generally
increased with increasing raw water particle concentration. Results
were consistent with previously collected data. Cryptosporidium and
Giardia were found in the majority of raw water sources, but
calculation of their log removal was limited by the concentration
present. River sources had a higher incidence of pathogen occurrence.
Direct filtration plants had higher levels of pathogens in the filtered
water than others in the survey.
Nearly all of the filter runs evaluated in the survey exhibited
spikes where filtered water particle counts increased, and pilot work
showed that pathogens are more likely to be released during these spike
events. Cryptosporidium removal in the pilot scale spiking study
averaged nearly 4 log, regardless of the influent oocyst concentration.
Pilot study results indicated a strong relationship between removal of
Cryptosporidium and removal of particles ( 3 [mu]m) during
runs using optimal coagulation and similar temperatures.
Patania et al. (1999) evaluated removal of Cryptosporidium at
varied raw water and filter effluent turbidity levels using direct
filtration. Runs were conducted with both low (2 NTU) and high (10 NTU)
raw water turbidity. Targeted filtered water turbidity was either 0.02
or 0.05 NTU. At equivalent filtered water turbidity, Cryptosporidium
removal was slightly higher when the raw water turbidity was higher.
Also, Cryptosporidium removal was enhanced by an average of 1.5 log
when steady-state filtered water turbidity was 0.02 NTU compared to
0.05 NTU.
Huck et al. (2000) evaluated filtration efficiency during optimal
and suboptimal coagulation conditions with two pilot scale filtration
plants. One plant employed a high coagulation dose for both total
organic carbon (TOC) and particle removal, and the second plant used a
low dose intended for particle removal only. Under optimal operating
conditions, which were selected to achieve filtered water turbidity
below 0.1 NTU, median Cryptosporidium removal was 5.6 log at the high
coagulant dose plant and 3 log at the low dose plant. Under suboptimal
coagulation conditions, where the coagulant dose was reduced to achieve
filtered water turbidity of 0.2 to 0.3 NTU, median Cryptosporidium
removals dropped to 3.2 log and 1 log at the high dose and low dose
plants, respectively. Oocyst removal also decreased substantially at
the end of the filter cycle, although this was not always indicated by
an increase in turbidity. Runs conducted with no coagulant resulted in
very little Cryptosporidium removal.
Emelko et al. (2000) investigated Cryptosporidium removal during
vulnerable filtration periods using a pilot scale direct filtration
system. The authors evaluated four different operational conditions:
stable, early breakthrough, late breakthrough, and end of run. During
stable operation, effluent turbidity was approximately 0.04 NTU and
Cryptosporidium removal ranged from 4.7 to 5.8 log. In the early
breakthrough period, effluent turbidity increased from approximately
0.04 to 0.2 NTU, and Cryptosporidium removal decreased significantly,
averaging 2.1 log. For the late breakthrough period, where effluent
turbidity began at approximately 0.25 NTU and ended at 0.35 NTU,
Cryptosporidium removal dropped to an average of 1.4 log. Two
experiments tested Cryptosporidium removal during the end-of-run
operation, when effluent turbidities generally start increasing.
Turbidity started at about 0.04 NTU for both experiments and ended at
0.06 NTU for the first experiment and 0.13 NTU for the second. Reported
Cryptosporidium removal ranged from 1.8 to 3.3 log, with an average of
2.5 log for both experiments.
Harrington et al. (2001) studied the removal of Cryptosporidium and
emerging pathogens by filtration, sedimentation, and dissolved air
flotation (DAF) using bench scale jar tests and pilot scale
conventional treatment trains. In the bench scale experiments, all run
at optimized coagulant doses, mean log removal of Cryptosporidium was
1.2 by sedimentation and 1.7 by DAF. Cryptosporidium removal was
similar in all four water sources that were evaluated and was not
significantly affected by lower pH or coagulant aid addition. However,
removal of Cryptosporidium was greater at 22[deg]C than at 5[deg]C, and
was observed to be higher with alum coagulant than with either
polyaluminum hydroxychlorosulfate or ferric chloride.
In the pilot scale experiments, mean log removal of Cryptosporidium
was 1.9 in filtered water with turbidity of 0.2 NTU or less. Removal
increased as filtered water turbidity dropped below 0.3 NTU. There was
no apparent effect of filtration rate on removal efficiency. In
comparing Cryptosporidium removal by sand, dual media (anthracite/
sand), and trimedia (anthracite/sand/garnet) filters, no difference was
observed near neutral pH. However, at pH 5.7, removal increased
significantly in the sand filter and it outperformed the other filter
media configurations. The authors found no apparent explanation for
this behavior. There was no observable effect of a turbidity spike on
Cryptosporidium removal.
Significance of Conventional and Direct Filtration Studies
The performance of treatment plants under current regulations is a
significant factor in determining the need for additional treatment. As
described in section IV.A, the proposed Cryptosporidium treatment
requirements associated with LT2ESWTR risk bins for filtered systems
are based, in part, on an estimate that conventional plants in
compliance with

[[Page 47662]]

the IESWTR achieve an average of 3 log Cryptosporidium removal. The
following discussion illustrates why EPA believes that available data
support this estimate.
While Cryptosporidium removal at full scale plants is difficult to
quantify due to limitations with analytical methods, pilot scale
studies show that reductions in aerobic spores and total particle
counts are often conservative indicators of filtration plant removal
efficiency for Cryptosporidium (Dugan et al. 2001, McTigue et al. 1998,
Yates et al. 1998, Emelko et al. 1999 and 2000). Surveys of full scale
plants have reported average reductions near 3 log for both aerobic
spores (Nieminski and Bellamy, 2000) and total particle counts (McTigue
et al. 1998). Consequently, these findings are consistent with an
estimate that average removal of Cryptosporidium by filtration plants
is approximately 3 log.
Pilot scale Cryptosporidium spiking studies (Dugan et al. 2001,
Huck et al. 2000, Emelko et al. 2000, McTigue et al. 1998, Patania et
al. 1995) suggest that a conventional treatment plant has the potential
to achieve greater than 5 log removal of Cryptosporidium under optimal
conditions. However, these high removals are typically observed at very
low filter effluent turbidity values, and the data show that removal
efficiency can decrease substantially over the course of a filtration
cycle or if coagulation is not optimized (Dugan et al. 2001, Huck et
al. 2000, Emelko et al. 2000, Harrington et al. 2001). Removal
efficiency also appears to be impacted by source water quality (Dugan
et al. 2001, McTigue et al. 1998). Given these considerations, EPA
believes that 3 log is a reasonable estimate of average Cryptosporidium
removal efficiency for conventional treatment plants in compliance with
the IESWTR or LT1ESWTR.
The Stage 2 M-DBP Advisory Committee did not address direct
filtration plants, which lack the sedimentation basin of a conventional
treatment train, but recommended that EPA address these plants in the
LT2ESWTR proposal (65 FR 83015, December 29, 2000) (USEPA 2000a). While
some studies have observed similar levels of Cryptosporidium removal in
direct and conventional filtration plants (Nieminski and Ongerth, 1995,
Ongerth and Pecoraro 1995), EPA has concluded that the majority of
available data support a lower estimate of Cryptosporidium removal
efficiency for direct filtration plants.
As described in section IV.C.5, pilot and full scale studies
demonstrate that sedimentation basins, which are absent in direct
filtration, can achieve 0.5 log or greater Cryptosporidium reduction
(Dugan et al. 2001, Patania et al. 1995, Edzwald and Kelly 1998,
Payment and Franco 1993, Kelley et al. 1995). In addition, Patania et
al. (1995) observed direct filtration to achieve less Cryptosporidium
removal than conventional treatment, and McTigue et al. (1998) found a
higher incidence of Cryptosporidium in the treated water of direct
filtration plants. Given these findings, EPA has estimated that direct
filtration plants achieve an average of 2.5 log Cryptosporidium
reduction (i.e., 0.5 log less than conventional treatment).
i. Dissolved air flotation. Dissolved air flotation (DAF) is a
solid-liquid separation process that can be used in conventional
treatment trains in place of gravity sedimentation. DAF takes advantage
of the buoyancy of oocysts by floating oocyst/particle complexes to the
surface for removal. In DAF, air is dissolved in pressurized water,
which is then released into a flotation tank containing flocculated
particles. As the water enters the tank, the dissolved air forms small
bubbles that collide with and attach to floc particles and float to the
surface (Gregory and Zabel, 1990).
In comparing DAF with gravity sedimentation, Plummer et al. (1995)
observed up to 0.81 log removal of oocysts in the gravity sedimentation
process, while DAF achieved 0.38 to 3.7 log removal, depending on
coagulant dose. Edzwald and Kelley (1998) demonstrated a 3 log removal
of oocysts using DAF, compared with a 1 log removal using gravity
sedimentation in the clarification process before filtration. In bench
scale testing by Harrington et al. (2001), DAF averaged 0.5 log higher
removal of Cryptosporidium than gravity sedimentation. Based on these
results, EPA has concluded that a treatment plant using DAF plus
filtration can achieve levels of Cryptosporidium removal equivalent to
or greater than a conventional treatment plant with gravity
sedimentation.
b. Slow sand filtration. Slow sand filtration is a process
involving passage of raw water through a bed of sand at low velocity
(generally less than 0.4 m/h) resulting in substantial particulate
removal by physical and biological mechanisms. For the LT2ESWTR
proposal, EPA has reviewed two additional studies of slow sand
filtration.
Fogel et al. (1993) evaluated removal efficiencies for
Cryptosporidium and Giardia with a full scale slow sand filtration
plant. The removals ranged from 0.1-0.5 log for Cryptosporidium and
0.9-1.4 log for Giardia. Raw water turbidity ranged from 1.3 to 1.6 NTU
and decreased to 0.35-0.31 NTU after filtration. The authors attributed
the low Cryptosporidium and Giardia removals to the relatively poor
grade of filter media and lower water temperature. The sand had a
higher uniformity coefficient than recommended by design standards.
This creates larger pore spaces within the filter bed that retard
biological removal capacity. Lower water temperatures (1 [deg]C) also
decreased biological activity in the filter media.
Hall et al. (1994) examined the removal of Cryptosporidium with a
pilot scale slow sand filtration plant. Cryptosporidium removals ranged
from 2.8 to 4.3 log after filter maturation, with an average of 3.8 log
(at least one week after filter scraping). Raw water turbidity ranged
from 3.0 NTU to 7.5 NTU for three of four runs and 15.0 NTU for a
fourth run. Filtered water turbidity was 0.2 to 0.4 NTU, except for the
fourth run which had 2.5 NTU filtered water turbidity. This study also
included an investigation of Cryptosporidium removal during filter
start-up where the filtration rate was slowly increased over a 4 day
period. Results indicate that filter ripening did not appear to affect
Cryptosporidium removal.
The study by Fogel et al. is significant because it indicates that
a slow sand filtration plant may achieve less than 2 log removal of
Cryptosporidium removal while being in compliance with the effluent
turbidity requirements of the IESWTR and LT1ESWTR. The authors
attributed this poor performance to the filter being improperly
designed, which, if correct, illustrates the importance of proper
design for removal efficiency in slow sand filters. In contrast, the
study by Hall et al. (1994) supports other work (Schuler and Ghosh
1991, Timms et al. 1995) in finding that slow sand filtration can
achieve Cryptosporidium removal greater than 3 log. Overall, this body
of work appears to show that slow sand filtration has the potential to
achieve Cryptosporidium removal efficiencies similar to that of a
conventional plant, but proper design and operation are critical to
realizing treatment goals.
c. Diatomaceous earth filtration. Diatomaceous earth filtration is
a process in which a precoat cake of filter media is deposited on a
support membrane and additional filter media is continuously added to
the feed water to maintain the permeability of the filter cake. Since
the IESWTR and LT1ESWTR, EPA has reviewed one new study of DE
filtration (Ongerth and Hutton 2001). It supports the findings of

[[Page 47663]]

earlier studies (Schuler and Gosh 1990, Ongerth and Hutton 1997) in
showing that a well designed and operated DE plant can achieve
Cryptosporidium removal equivalent to a conventional treatment plant
(i.e., average of 3 log).
d. Other filtration technologies. In today's proposal, information
about bag filters, cartridge filters, and membranes, including criteria
for awarding Cryptosporidium treatment credit, is presented in section
IV.C as part of the microbial toolbox. Section IV.C also addresses
credit for pretreatment options like presedimentation basins and bank
filtration.
e. Inactivation. Substantial advances in understanding of
Cryptosporidium inactivation by ozone, chlorine dioxide, and UV have
been made following the IESWTR and LT1ESWTR. These advances have
allowed EPA to develop criteria to award Cryptosporidium treatment
credit for these disinfectants. Relevant information is summarized
next, with additional information sources noted.
i. Ozone and chlorine dioxide. With the completion of several major
studies, EPA has acquired sufficient information to develop standards
for the inactivation of Cryptosporidium by ozone and chlorine dioxide.
For both of these disinfectants, today's proposal includes CT tables
that specify a level of Cryptosporidium treatment credit based on the
product of disinfectant concentration and contact time.
For ozone, the CT tables in today's proposal were developed through
considering four sets of experimental data: Li et al. (2001), Owens et
al. (2000), Oppenheimer et al. (2000), and Rennecker et al. (1999).
Chlorine dioxide CT tables are based on three experimental data sets:
Li et al. (2001), Owens et al. (1999), and Ruffell et al. (2000).
Together these studies provide a large body of data that covers a range
of water matrices, both laboratory and natural. While the data exhibit
variability, EPA believes that collectively they are sufficient to
determine appropriate levels of treatment credit as a function of
disinfection conditions. CT tables for ozone and chlorine dioxide
inactivation of Cryptosporidium are presented in Section IV.C.14 of
this preamble.
ii. Ultraviolet light. A major recent development is the finding
that UV light is highly effective for inactivating Cryptosporidium and
Giardia at low doses. Research prior to 1998 had indicated that very
high doses of UV light were required to achieve substantial
disinfection of protozoa. However, as noted previously, these results
were largely based on the use of in vitro assays, which were later
shown to substantially overestimate the UV doses required to prevent
infection (Clancy et al. 1998, Bukhari et al. 1999, Craik et al. 2000).
Recent research using in vivo assays (e.g., neonatal mouse infectivity)
and cell culture techniques to measure infectivity has provided strong
evidence that both Cryptosporidium and Giardia are highly sensitive to
low doses of UV.

BILLING CODE 6560-50-P

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[GRAPHIC] [TIFF OMITTED] TP11AU03.004

BILLING CODE 6560-50-C
Figure III-5 presents data from selected studies of UV inactivation
of Cryptosporidium. While the data in Figure III-5 show substantial
scatter, they are consistent in demonstrating a high level of
inactivation at relatively low UV doses. These studies generally
demonstrated at least 3 log Cryptosporidium inactivation at UV doses of
10 mJ/cm ² and higher. In comparison, typical UV dose for
drinking water disinfection are 30 to 40 mJ/cm ². A recent
investigation by Clancy et al. (2002) showed that UV light at 10 mJ/cm
² provided at least 4 log inactivation of five strains of
Cryptosporidium that are infectious to humans. Studies of UV
inactivation of Giardia have reported similar results (Craik et al.
2000, Mofidi et al. 2002, Linden et al. 2002, Campbell and Wallis 2002,
Hayes et al. 2003).
In addition to efficacy for protozoa inactivation, data indicate
that UV disinfection does not promote the formation of DBPs (Malley et
al. 1995, Zheng et al. 1999). Malley et al. (1995) evaluated DBP
formation in a number of surface and ground waters with UV doses
between 60 and 200 mJ/cm\2\. UV light did not directly form DBPs, such
as trihalomethanes (THM) and haloacetic acids (HAA), and did not alter
the concentration or species of DBPs formed by post-disinfection with
chlorine or chloramines. A study by Zheng et al. (1999) reported that
applying UV light following chlorine disinfection had little impact on
THM and HAA formation. In addition, data suggest that photolysis of
nitrate to nitrite, a potential concern with certain types of UV lamps,
will not result in nitrite levels near the MCL under typical drinking
water conditions (Peldszus et al. 2000, Sharpless and Linden 2001).
These studies demonstrate that UV light is an effective technology
for inactivating Giardia and Cryptosporidium, and that it does not form
DBPs at levels of concern in drinking water. Section IV.C.15 describes
proposed criteria for awarding treatment credit for UV inactivation of
Cryptosporidium, Giardia lamblia, and viruses. These criteria include
UV dose tables, validation testing, and monitoring standards. In
addition, EPA is preparing a UV Disinfection Guidance Manual with
information on design, testing, and operation of UV systems. A draft of
this guidance is available in the docket for today's proposal (http://
www.epa.gov/edocket/).
iii. Significance of new information on inactivation. The research
on ozone, chlorine dioxide, and UV light described in this proposal has
made these disinfectants available for systems to use in meeting
additional Cryptosporidium treatment requirements under LT2ESWTR. This
overcomes a significant limitation to establishing inactivation
requirements for Cryptosporidium that existed when the IESWTR was
developed. The Stage 1 Advisory Committee recognized the need for
inactivation criteria if EPA were to consider a risk based proposal

[[Page 47665]]

for Cryptosporidium in future rulemaking (62 FR 59498, November 3,
1997) (USEPA 2000b). The CT tables for ozone and chlorine dioxide
provide such criteria. In addition, the availability of UV furnishes
another relatively low cost tool to achieve Cryptosporidium
inactivation and DBP control.
While no single treatment technology is appropriate for all
systems, EPA believes that these disinfectants, along with the other
management and treatment options in the microbial toolbox presented in
section IV.C, make it feasible for systems to meet the additional
Cryptosporidium treatment requirements in today's proposal.

IV. Discussion of Proposed LT2ESWTR Requirements

A. Additional Cryptosporidium Treatment Technique Requirements for
Filtered Systems

1. What Is EPA Proposing Today?
a. Overview of framework approach. EPA is proposing treatment
technique requirements to supplement the existing requirements of the
SWTR, IESWTR, and LT1ESWTR (see section II.B). The proposed
requirements will achieve increased protection against Cryptosporidium
in public water systems that use surface water or ground water under
the direct influence of surface water as sources. Under this proposal,
filtered systems will be assigned to one of four risk categories (or
``bins''), based on the results of source water Cryptosporidium
monitoring. Systems assigned to the lowest risk bin incur no additional
treatment requirements, while systems assigned to higher risk bins must
reduce Cryptosporidium levels beyond IESWTR and LT1ESWTR requirements.
Systems will comply with additional Cryptosporidium treatment
requirements by selecting treatment and management strategies from a
``microbial toolbox'' of control options.
Today's proposal reflects recommendations from the Stage 2 M-DBP
Federal Advisory Committee (65 FR 83015, December 29, 2000) (USEPA
2000a), which described this approach as a ``microbial framework''.
This approach targets additional treatment requirements to those
systems with the highest source water Cryptosporidium levels and,
consequently, the highest vulnerability to this pathogen. In so doing,
today's proposal builds upon the current treatment technique
requirement for Cryptosporidium under which all filtered systems must
achieve at least a 2 log reduction, regardless of source water quality.
The intent of this proposal is to assure that public water systems with
the higher risk source water achieve a level of public health
protection commensurate with systems with less contaminated source
water.
b. Monitoring requirements. Today's proposal requires systems to
monitor their source water (influent water prior to treatment plant)
for Cryptosporidium, E. coli, and turbidity. The purpose of the
monitoring is to assess source water Cryptosporidium levels and,
thereby, classify systems in different risk bins. Proposed monitoring
requirements for large and small systems are summarized in Table IV-I
and are characterized in the following discussion.
Large Systems
Large systems (serving at least 10,000 people) must sample their
source water at least monthly for Cryptosporidium, E. coli, and
turbidity for a period of 2 years, beginning no later than 6 months
after LT2ESWTR promulgation. Systems may sample more frequently (e.g.,
twice-per-month, once-per-week), provided the same sampling frequency
is used throughout the 2-year monitoring period. As described in
section IV.A.1.c, systems that sample more frequently (at least twice-
per-month) use a different calculation that is potentially less
conservative to determine their bin classification.
The purpose of requiring large systems to collect E. coli and
turbidity data is to further evaluate these parameters as indicators to
identify drinking water sources that are susceptible to high
concentrations of Cryptosporidium. As described next, these data will
be applied to small system LT2ESWTR monitoring.
Small Systems
EPA is proposing a 2-phase monitoring strategy for small systems
(serving fewer than 10,000 people) to reduce their monitoring burden.
This approach is based on Information Collection Rule and ICRSS data
indicating that systems with low source water E. coli levels are likely
to have low Cryptosporidium levels, such that additional treatment
would not be required under the LT2ESWTR. Under this approach, small
systems must initially conduct one year of bi-weekly sampling (one
sample every two weeks) for E. coli, beginning 2.5 years after LT2ESWTR
promulgation. Small systems are triggered into Cryptosporidium
monitoring only if the initial E. coli monitoring indicates a mean
concentration greater than 10 E. coli/100 mL for systems using a
reservoir or lake as their primary source or greater than 50 E. coli/
100 mL for systems using a flowing stream as their primary source.
Small systems that exceed these E. coli trigger values must conduct one
year of twice-per-month Cryptosporidium sampling, beginning 4 years
after LT2ESWTR promulgation.
The analysis supporting the proposed E. coli values that trigger
Cryptosporidium monitoring by small systems is presented in Section
IV.A.2. However, as recommended by the Stage 2 M-DBP Advisory
Committee, EPA will evaluate Cryptosporidium indicator relationships in
the LT2ESWTR monitoring data collected by large systems. If these data
support the use of different indicator levels to trigger small system
Cryptosporidium monitoring, EPA will issue guidance with
recommendations. The proposed LT2ESWTR allows States to specify
alternative indicator values for small systems, based on EPA guidance.

Table IV-1.--LT2ESWTR Monitoring Requirements
--------------------------------------------------------------------------------------------------------------------------------------------------------
Monitoring parameters and sample frequency requirements
Public water systems Monitoring begins Monitoring duration ---------------------------------------------------------------------
Cryptosporidium E. coli Turbidity
--------------------------------------------------------------------------------------------------------------------------------------------------------
Large systems (serving 10,000 or 6 months after 2 years.............. minimum 1 sample/month minimum 1 sample/ minimum 1 measurement/
more people). promulgation of ^b. month ^b. month ^b.
LT2ESWTR ^a.
Small systems (serving fewer than 30 months (2\1/2\ 1 year............... See following rows.... 1 sample every two N/A
10,000 people). years) after weeks.
promulgation of
LT2ESWTR.
------------------------------------

[[Page 47666]]

Possible additional monitoring requirement for Cryptosporidium. If small systems exceed E. coli trigger levels ^c, then * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Small systems (serving fewer than 48 months (4 years) 1 year............... 2 samples/month....... N/A.................. N/A.
10,000 people) ^c. after promulgation of
LT2ESWTR.
--------------------------------------------------------------------------------------------------------------------------------------------------------
^a Public water systems may use equivalent previously collected (grandfathered) data to meet LT2ESWTR requirements. See section IV.A.1.d for details.
^b Public water systems may sample more frequently (e.g., twice-per-month, once-per-week).
^c Small systems must monitor for Cryptosporidium for one year, beginning 6 months after completion of E. coli monitoring, if the E. coli annual mean
concentration exceeds 10/100 mL for systems using lakes/reservoir sources or 50/100 mL for systems using flowing stream sources.
N/A = Not applicable. No monitoring required.

Sampling Location
Source water samples must be representative of the intake to the
filtration plant. Generally, sampling must be performed individually
for each plant that treats a surface water source. However, where
multiple plants receive all of their water from the same influent
(e.g., multiple plants draw water from the same pipe), the same set of
monitoring results may be applicable to each plant. Typically, samples
must be collected prior to any treatment, with exceptions for certain
pretreatment processes. Directions on sampling location for plants
using off-stream storage, presedimentation, and bank filtration are
provided in section IV.C.
Systems with plants that use multiple water sources at the same
time must collect samples from a tap where the sources are combined
prior to treatment if available. If a blended source tap is not
available, systems must collect samples from each source and either
analyze a weighted composite (blended) sample or analyze samples from
each source separately and determine a weighted average of the results.
Sampling Schedule
Large systems must submit a sampling schedule to EPA within 3
months after promulgation of the LT2ESWTR. Small systems must submit a
sampling schedule for E. coli monitoring to their primacy agency within
27 months after rule promulgation; small systems required to monitor
for Cryptosporidium must submit a Cryptosporidium sampling schedule
within 45 months after promulgation. The sampling schedules must
specify the calendar date on which the system will collect each sample
required under the LT2ESWTR. Scheduled sampling dates should be evenly
distributed throughout the monitoring period, but may be arranged to
accommodate holidays, weekends, and other events when collecting or
analyzing a sample would be problematic.
Systems must collect samples within 2 days before or 2 days after a
scheduled sampling date. If a system does not sample within this 5-day
window, the system will incur a monitoring violation unless either of
the following two conditions apply:

(1) If extreme conditions or situations exist that may pose
danger to the sample collector, or which are unforeseen or cannot be
avoided and which cause the system to be unable to sample in the
required time frame, the system must sample as close to the required
date as feasible and submit an explanation for the alternative
sampling date with the analytical results.
(2) Systems that are unable to report a valid Cryptosporidium
analytical result for a scheduled sampling date due to failure to
comply with analytical method quality control requirements
(described in section IV.K) must collect a replacement sample within
14 days of being notified by the laboratory or the State that a
result cannot be reported for that date. Systems must submit an
explanation for the replacement sample with the analytical results.
Where possible, the replacement sample collection date should not
coincide with any other scheduled LT2ESWTR sampling dates.

Approved Analytical Methods and Laboratories
To ensure the quality of LT2ESWTR monitoring data, today's proposal
requires systems to use approved methods for Cryptosporidium, E. coli,
and turbidity analyses (see section IV.K for sample analysis
requirements), and to have these analyses performed by approved
laboratories (described in section IV.L).
Reporting
Because source water monitoring by large systems will begin 6
months after promulgation of the LT2ESWTR, EPA is proposing that
monitoring results for large systems be reported directly to the Agency
though an electronic data system (described in section IV.J), similar
to the approach currently used under the Unregulated Contaminants
Monitoring Rule (64 FR 50555, September 17, 1999) (USEPA 1999c). Small
systems will report data to EPA or States, depending on whether States
have assumed primacy for the LT2ESWTR.
Previously Collected Monitoring Results
EPA is proposing to allow systems to use previously collected
(i.e., grandfathered) Cryptosporidium monitoring data to meet LT2ESWTR
monitoring requirements if the data are equivalent to data that will be
collected under the rule (e.g., sample volume, sampling frequency,
analytical method quality control). Criteria for acceptance of
previously collected data are specified in section IV.A.1.d.
Providing Additional Treatment Instead of Monitoring
Filtered systems are not required to conduct source water
monitoring under the LT2ESWTR if the system currently provides or will
provide a total of at least 5.5 log of treatment for Cryptosporidium,
equivalent to meeting the treatment requirements of Bin 4 as shown in
Table IV-4 (i.e., the maximum required in today's proposal). Systems
must notify EPA or the State not later than the date the system is
otherwise required to submit a sampling schedule for monitoring and
must install and operate technologies to provide a total of at least
5.5 log of treatment for Cryptosporidium by the applicable date in
Table IV-23. Any filtered system that fails to complete LT2ESWTR
monitoring requirements must meet the treatment requirements for Bin 4.
Ongoing Source Assessment and Second Round of Monitoring
Because LT2ESWTR treatment requirements are related to the degree
of source water contamination, today's proposal contains provisions to
assess changes in a system's source water

[[Page 47667]]

quality following initial risk bin classification. These provisions
include source water assessment during sanitary surveys and a second
round of monitoring.
Under 40 CFR 142.16(b)(3)(i), source water is one of the components
that States must address during the sanitary surveys that are required
for surface water systems. These sanitary surveys must be conducted
every 3 years for community systems and every 5 years for non-community
systems. EPA is proposing that if the State determines during the
sanitary survey that significant changes have occurred in the watershed
that could lead to increased contamination of the source water, the
State may require systems to implement specific actions to address the
contamination. These actions include implementing options from the
microbial toolbox discussed in section IV.C.
EPA is proposing that systems conduct a second round of source
water monitoring, beginning six years after systems are initially
classified in LT2ESWTR risk bins. To prepare for this second round of
monitoring, the Advisory Committee recommended that EPA initiate a
stakeholder process four years after large systems complete initial bin
classification. The purpose of the stakeholder process would be to
review risk information, and to determine the appropriate analytical
method, monitoring frequency, monitoring location, and other criteria
for the second round of monitoring.
If EPA does not modify LT2ESWTR requirements through issuing a new
regulation prior to the second round of monitoring, systems must carry
out this monitoring according to the requirements that apply to the
initial round of source water monitoring. Moreover, systems will be
reclassified in LT2ESWTR risk bins based on the second round monitoring
results and using the criteria specified in this section for initial
bin classification. However, if EPA changes the LT2ESWTR risk bin
structure to reflect a new analytical method or new risk information,
systems will undergo a site specific risk characterization in
accordance with the revised rule.

c. Treatment Requirements

i. Bin classification. Under the proposed LT2ESWTR, surface water
systems that use filtration will be classified in one of four
Cryptosporidium concentration categories (bins) based on the results of
source water monitoring. As shown in Table IV-2, bin classification is
determined by averaging the Cryptosporidium concentrations measured for
individual samples.

Table IV-2.-- Bin Classification Table for Filtered Systems
------------------------------------------------------------------------
If your average Cryptosporidium Then your bin classification
concentration ¹ is . . . is . . .
------------------------------------------------------------------------
Cryptosporidium <0.075/L.................. Bin 1.
0.075/L <= Cryptosporidium < 1.0/L........ Bin 2.
1.0/L <= Cryptosporidium < 3.0/L.......... Bin 3.
Cryptosporidium = 3.0/L........ Bin 4.
------------------------------------------------------------------------
\1\ All concentrations shown in units of oocysts/L

The approach that systems will use to average individual sample
concentrations to determine their bin classification depends on the
number of samples collected and the length of the monitoring period.
Systems serving at least 10,000 people are required to monitor for 24
months, and their bin classification must be based on the following:
(1) Highest twelve month running annual average for monthly
sampling, or
(2) two year mean if system conducts twice-per-month or more
frequent sampling for 24 months (i.e., at least 48 samples).
Systems serving fewer than 10,000 people are required to collect 24
Cryptosporidium samples over 12 months if they exceed the E. coli
trigger level, and their bin classification must be based on the mean
of the 24 samples. As noted earlier, systems that fail to complete the
required Cryptosporidium monitoring will be classified in Bin 4.
When determining LT2ESWTR bin classification, systems must
calculate individual sample concentrations using the total number of
oocysts counted, unadjusted for method recovery, divided by the volume
assayed (see section IV.K for details). As described in Section IV.A.2,
the ranges of Cryptosporidium concentrations that define LT2ESWTR bins
reflect consideration of analytical method recovery and the percent of
Cryptosporidium oocysts that are infectious. Consequently, sample
analysis results will not be adjusted for these factors.
ii. Credit for treatment in place. A key parameter in determining
additional Cryptosporidium treatment requirements is the credit that
plants receive for treatment currently provided (i.e., treatment in
place). For baseline treatment requirements established by the SWTR,
IESWTR, and LT1ESWTR that apply uniformly to filtered systems, the
Agency has awarded credit based on the minimum removal that plants will
achieve. Specifically, in the IESWTR and LT1ESWTR, EPA determined that
filtration plants, including conventional, direct, slow sand, and DE,
meeting the required filter effluent turbidity criteria will achieve at
least 2 log removal of Cryptosporidium. Consequently, these plants were
awarded a 2 log Cryptosporidium removal credit, which equals the
maximum treatment required under these regulations.
The LT2ESWTR will supplement existing regulations by mandating
additional treatment at certain plants based on site specific
conditions (i.e., source water Cryptosporidium level). When assessing
the need for additional treatment beyond baseline requirements for
higher risk systems, the Agency has determined that it is appropriate
to consider the average removal efficiency achieved by treatment
plants. As described in section III.D, EPA has concluded that
conventional, slow sand, and DE plants in compliance with the SWTR,
IESWTR, and LT1ESWTR achieve an average Cryptosporidium reduction of 3
log. Consequently, EPA is proposing to award these plants a 3 log
credit towards Cryptosporidium treatment requirements under the
LT2ESWTR. As noted previously, this approach is consistent with the
Stage 2 M-DBP Agreement in Principle.
For other types of filtration plants, treatment credit under the
LT2ESWTR differs. Conventional treatment is defined in 40 CFR 141.2 as
a series of processes including coagulation, flocculation,
sedimentation, and filtration, with sedimentation defined as a process
for removal of solids before filtration by gravity or separation. Thus,
plants with separation (i.e., clarification) processes other than
gravity sedimentation between flocculation and filtration, such as DAF,
may be regarded as conventional treatment for purposes of awarding
treatment credit under the LT2ESWTR. However, for direct filtration
plants, which lack a sedimentation process, EPA is proposing a 2.5 log
Cryptosporidium removal credit. Studies that support awarding direct
filtration plants less treatment credit than conventional plants are
summarized in section III.D.
EPA is unable to estimate an average log removal for other
filtration technologies like membranes, bag filters, and cartridge
filters, due to variability among products. As a result, credit for
these devices must be determined by the State, based on product
specific testing described in section IV.C or other criteria approved
by the State.

[[Page 47668]]

Table IV-3 presents the credit proposed for different types of
plants towards LT2ESWTR Cryptosporidium treatment requirements. As
described in section IV.C.18, a State may award greater credit to a
system that demonstrates through a State-approved protocol that it
reliably achieves a higher level of Cryptosporidium removal.
Conversely, a State may award less credit to a system where the State
determines, based on site specific information, that the system is not
achieving the degree of Cryptosporidium removal indicated in Table IV-
3.

Table IV-3.--Cryptosporidium Treatment Credit Towards LT2ESWTR Requirements ¹
----------------------------------------------------------------------------------------------------------------
Conventional
treatment Slow sand or Alternative
Plant type (includes Direct filtration diatomaceous earth filtration
softening) filtration technologies
----------------------------------------------------------------------------------------------------------------
Treatment credit................ 3.0 log........... 2.5 log........... 3.0 log........... Determined by
State ².
----------------------------------------------------------------------------------------------------------------
\1\ Applies to plants in full compliance with the SWTR, IESWTR, and LT1ESWTR as applicable
\2\ Credit must be determined through product or site specific assessment

iii. Treatment requirements associated with LT2ESWTR bins
The treatment requirements associated with LT2ESWTR risk bins are
shown in Table IV-4. The total Cryptosporidium treatment required for
Bins 2, 3, and 4 is 4.0 log, 5.0 log, and 5.5 log, respectively. For
conventional (including softening), slow sand, and DE plants that
receive 3.0 log credit for compliance with current regulations,
additional Cryptosporidium treatment of 1.0 to 2.5 log is required when
classified in Bins 2-4. Direct filtration plants that receive 2.5 log
credit for compliance with current regulations must achieve 1.5 to 3.0
log of additional Cryptosporidium treatment in Bins 2-4.
For systems using alternative filtration technologies, such as
membranes or bag/cartridge filters, and classified in Bins 2-4, the
State must determine additional treatment requirements based on the
credit awarded to a particular technology. The additional treatment
must be such that plants classified in Bins 2, 3, and 4 achieve the
total required Cryptosporidium reductions of 4.0, 5.0, and 5.5 log,
respectively.

Table IV-4.--Treatment Requirements Per LT2ESWTR Bin Classification
----------------------------------------------------------------------------------------------------------------
And you use the following filtration treatment in full compliance with the
SWTR, IESWTR, and LT1ESWTR (as applicable), then your additional treatment
requirements are . . .
-------------------------------------------------------------------------------
If your bin classification is . Conventional
. . filtration Slow sand or Alternative
treatment Direct filtration diatomaceous earth filtration
(includes filtration technologies
softening)
----------------------------------------------------------------------------------------------------------------
Bin 1........................... No additional No additional No additional No additional
treatment. treatment. treatment. treatment.
Bin 2........................... 1 log treatment 1.5 log treatment 1 log treatment As determined by
\1\. \1\. \1\. the State ^1, ³.
Bin 3........................... 2 log treatment 2.5 log treatment 2 log treatment As determined by
\2\. \2\. \2\. the State ^2, ⁴.
Bin 4........................... 2.5 log treatment 3 log treatment 2.5 log treatment As determined by
\2\. \2\. \2\. the State ^2, ⁵.
----------------------------------------------------------------------------------------------------------------
\1\ Systems may use any technology or combination of technologies from the microbial toolbox.
\2\ Systems must achieve at least 1 log of the required treatment using ozone, chlorine dioxide, UV, membranes,
bag/cartridge filters, or bank filtration.
\3\ Total Cryptosporidium removal and inactivation must be at least 4.0 log.
\4\ Total Cryptosporidium removal and inactivation must be at least 5.0 log.
\5\ Total Cryptosporidium removal and inactivation must be at least 5.5 log.

Plants can achieve additional Cryptosporidium treatment credit
through implementing pretreatment processes like presedimentation or
bank filtration, by developing a watershed control program, and by
applying additional treatment steps like UV, ozone, chlorine dioxide,
and membranes. In addition, plants can receive additional credit for
existing treatment through achieving very low filter effluent turbidity
or through a demonstration of performance. Section IV.C presents
criteria for awarding Cryptosporidium treatment credit to a host of
treatment and control options, including those listed here and others,
which are collectively termed the ``microbial toolbox''.
Systems in Bin 2 can meet additional Cryptosporidium treatment
requirements through using any option or combination of options from
the microbial toolbox. In Bins 3 and 4, systems must achieve at least 1
log of the additional treatment requirement through using ozone,
chlorine dioxide, UV, membranes, bag filtration, cartridge filtration,
or bank filtration.
d. Use of previously collected data. Today's proposal allows
systems with previously collected Cryptosporidium data (i.e., data
collected prior to the required start of monitoring under the LT2ESWTR)
that are equivalent in sample number, frequency, and data quality to
data that will be collected under the LT2ESWTR to use those data in
lieu of conducting new monitoring. Specifically, EPA is proposing that
Cryptosporidium sample analysis results collected prior to promulgation
of the LT2ESWTR must meet the following criteria to be used for bin
classification:
[sbull] Samples were analyzed by laboratories using validated
versions of EPA Methods 1622 or 1623 and meeting the quality control
criteria specified in these methods (USEPA 1999a, USEPA 1999b, USEPA
2001e, USEPA 2001f).
[sbull] Samples were collected no less frequently than each
calendar month on a regular schedule, beginning no earlier than January
1999 (when EPA Method 1622 was first released as an interlaboratory-
validated method).
[sbull] Samples were collected in equal intervals of time over the
entire collection period (e.g., weekly,

[[Page 47669]]

monthly). The allowances for deviations from a sampling schedule
specified under IV.A.1.b for LT2ESWTR monitoring apply to grandfathered
data.
[sbull] Samples were collected at the correct location as specified
for LT2ESWTR monitoring. Systems must report the use of bank
filtration, presedimentation, and raw water off-stream storage during
sampling.
[sbull] For each sample, the laboratory analyzed at least 10 L of
sample or at least 2 mL of packet pellet volume or as much volume as
two filters could accommodate before clogging (applies only to filters
that have been approved by EPA for use with Methods 1622 and 1623).
[sbull] The system must certify that it is reporting all
Cryptosporidium monitoring results generated by the system during the
time period covered by the previously collected data. This applies to
samples that were (a) collected from the sampling location used for
LT2ESWTR monitoring, (b) not spiked, and (c) analyzed using the
laboratory's routine process for Method 1622 or 1623 analyses.
[sbull] The system must also certify that the samples were
representative of a plant's source water(s) and the source water(s)
have not changed.
If a system has at least two years of Cryptosporidium data
collected before promulgation of the LT2ESWTR and the system does not
intend to conduct new monitoring under the rule, the system must submit
the data and the required supporting documentation to EPA no later than
two months following promulgation of the rule. EPA will notify the
system within four months following LT2ESWTR promulgation as to whether
the data are sufficient for bin determination. Unless EPA notifies the
system in writing that the previously collected data are sufficient for
bin determination, the system must conduct source water Cryptosporidium
monitoring as described in section IV.A.1.b of this preamble.
If a system intends to grandfather fewer than two years of
Cryptosporidium data, or if a system intends to grandfather 2 or more
years of previously collected data and also to conduct new monitoring
under the rule, the system must submit the data and the required
supporting documentation to EPA no later than eight months following
promulgation of the rule. Systems must conduct monitoring as described
in section IV.A.1.b until EPA notifies the system in writing that it
has at least 2 years of acceptable data. See section IV.J for
additional information on reporting requirements associated with
previously collected data.
2. How Was This Proposal Developed?
The monitoring and treatment requirements for filtered systems
proposed under the LT2ESWTR stem from the data and analyses described
in this section and reflect recommendations made by the Stage 2 M-DBP
Federal Advisory Committee (65 FR 83015) (USEPA 2000a).
a. Basis for targeted treatment requirements. Under the IESWTR, EPA
established an MCLG of zero for Cryptosporidium at the genus level
based on the public health risk associated with this pathogen. The
IESWTR included a 2 log treatment technique requirement for medium and
large filtered systems that controlled for Cryptosporidium as close to
the MCLG as was then deemed technologically feasible, taking costs into
consideration. The LT1ESWTR extended this requirement to small systems.
Given the advances that have occurred subsequent to the IESWTR in
available technology to measure and treat for Cryptosporidium, a key
question for the LT2ESWTR was the extent to which Cryptosporidium
should be further controlled to approach the MCLG of zero, considering
technical feasibility, costs, and potential risks from DBPs.
The data and analysis presented in Section III of this preamble
suggest wide variability in possible risk from Cryptosporidium among
public water systems. This variability is largely due to three factors:
(1) The broad distribution of Cryptosporidium occurrence levels among
source waters, (2) disparities in the efficacy of treatment provided by
plants, and (3) differences in the infectivity among Cryptosporidium
isolates. EPA and the Advisory Committee considered this wide range of
possible risks and the desire to address systems where the 2 log
removal requirement established by the IESWTR and LT1ESWTR may not
provide adequate public health protection.
A number of approaches were evaluated for furthering control of
Cryptosporidium. One approach was to require all systems to provide the
same degree of additional treatment for Cryptosporidium (i.e., beyond
that required by the IESWTR and LT1ESWTR). This approach could ensure
that most systems, including those with poor quality source water,
would be adequately protective. The uniformity of this approach has the
advantage of minimizing transactional costs for determining what must
be done by a particular system to comply. However, a significant
downside is that it may require more treatment, with consequent costs,
than is needed by many systems with low source water Cryptosporidium
levels. In addition, there were concerns with the feasibility of
requiring almost all surface water treatment plants to install
additional treatment processes for Cryptosporidium.
A second approach was to base additional treatment requirements on
a plant's source water Cryptosporidium level. Under this approach,
systems monitor their source water for Cryptosporidium, and additional
treatment is required only from those systems that exceed specified
oocyst concentrations. This has the advantage of targeting additional
public health protection to those systems with higher vulnerability to
Cryptosporidium, while avoiding the imposition of higher treatment
costs on systems with the least contaminated source water. In
consideration of these advantages, the Advisory Committee recommended
and EPA is proposing this second approach for filtered systems under
the LT2ESWTR.
b. Basis for bin concentration ranges and treatment requirements.
The proposed LT2ESWTR will classify plants into different risk bins
based on the source water Cryptosporidium level, and the bin
classification will determine the extent to which additional treatment
beyond IESWTR and LT1ESWTR is required. Two questions were central in
developing the proposed bin concentration ranges and additional
treatment requirements:
[sbull] What is the risk associated with a given level of
Cryptosporidium in a drinking water source?
[sbull] What degree of additional treatment should be required for
a given source water Cryptosporidium level?
This section addresses these two questions by first summarizing how
EPA assessed the risk associated with Cryptosporidium in drinking
water, followed by a description of how EPA and the Advisory Committee
used this type of information in identifying LT2ESWTR bin concentration
ranges and treatment requirements. For additional information on these
topics, see Economic Analysis for the LT2ESWTR (USEPA 2003a).
i. What is the risk associated with a given level of
Cryptosporidium in a drinking water source? The risk of infection from
Cryptosporidium in drinking water is a function of infectivity (i.e.,
dose-response associated with ingestion) and exposure. Section III.B
summarizes available data on Cryptosporidium infectivity. EPA conducted
a meta-analysis of reported infection rates from human feeding

[[Page 47670]]

studies with 3 Cryptosporidium isolates. This analysis produced an
estimate for the mean probability of infection given a dose of one
oocyst near 0.09 (9%), with 10th and 90th percentile confidence values
of 0.011 and 0.22, respectively.
Exposure to Cryptosporidium depends on the concentration of oocysts
in the source water, the efficiency of treatment plants in removing
oocysts, and the volume of water ingested (exposure can also occur
through interactions with infected individuals). Based on data
presented in section III.D, EPA has estimated that filtration plants in
compliance with the IESWTR or LT1ESWTR reduce source water
Cryptosporidium levels by 2 to 5 log (99% to 99.999%), with an average
reduction near 3 log. For drinking water consumption, EPA uses a
distribution, derived from the United States Department of
Agriculture's (USDA) 1994-96 Continuing Survey of Food Intakes by
Individuals, with a mean value of 1.2 L/day. Average annual days of
exposure to drinking water in CWS, non-transient non-community water
systems (NTNCWS), and transient non-community water systems (TNCWS) are
estimated at 350 days, 250 days, and 10 days, respectively. (The
Economic Analysis for the LT2ESWTR (USEPA 2003a) provides details on
all parameters listed here, as well as morbidity, mortality, and other
risk factors.)
Using an estimate of 1.2 L/day consumption and a mean probability
of infection of 0.09 for one oocyst ingested, the daily risk of
infection (DR) is as follows:

DR = (oocysts/L in source water) x (percent remaining after treatment)
x (1.2 L/day) x (0.09).

The annual risk (AR) of infection for a CWS is

AR = 1-(1-DR)\350\

where 350 represents days of exposure in a CWS.
Table IV-5 presents estimates of the mean annual risk of infection
by Cryptosporidium in CWSs for selected source water infectious oocyst
concentrations and filtration plant removal efficiencies.

Table IV-5.--Annual Risk of Cryptosporidium Infection in CWSs That
Filter, as a Function of Source Water Infectious Oocyst Concentration
and Treatment Efficiency
------------------------------------------------------------------------
Source water Mean annual risk of infection for different levels of
concentration treatment efficiency (log removal) \1\
(infectious -------------------------------------------------------
oocysts per 5
liter) 2 log 3 log 4 log log
------------------------------------------------------------------------
0.0001 3.8E-05 3.8E-06 3.8E-07 3.8
E-0
8
0.001 3.7E-04 3.8E-05 3.8E-06 3.8
E-0
7
0.01 3.7E-03 3.7E-04 3.8E-05 3.8
E-0
6
0.1 3.7E-02 3.7E-03 3.7E-04 3.8
E-0
5
1 0.31 3.7E-02 3.7E-03 3.7
E-0
4
10 0.89 0.31 3.7E-02 3.7
E-0
3
------------------------------------------------------------------------
\1\ Scientific notation (E^-x) designates 10^-x

For example, Table IV-5 shows that if a filtration plant had a mean
concentration of infectious Cryptosporidium in the source water of 0.01
oocysts/L, and the filtration plant averaged 3 log removal, the mean
annual risk of infection by Cryptosporidium is estimated as 3.7 x
10^-4 (3.7 infections per 10,000 consumers).
ii. What degree of additional treatment should be required for a
given source water Cryptosporidium level? In order to develop targeted
treatment requirements for the LT2ESWTR, it was necessary to identify a
source water Cryptosporidium level above which additional treatment by
filtered systems would be required. Based on the type of risk
information shown in Table IV-5, EPA and Advisory Committee
deliberations focused on mean source water Cryptosporidium
concentrations in the range of 0.01 to 0.1 oocysts/L as appropriate
threshold values for prescribing additional treatment.
Analytical method and sampling constraints were a significant
factor in setting the specific Cryptosporidium level that triggers
additional treatment by filtered systems. The number of samples that
systems can be required to analyze for Cryptosporidium is limited.
Consequently, if the bin threshold concentration for additional
treatment was set near 0.01 oocysts/L, systems could exceed this level
due to a very low number of oocysts being detected. For example, if
systems took monthly 10 L samples and bin classification was based on a
maximum running annual average, then a system would exceed a mean
concentration of 0.01 oocysts/L by counting only 2 oocysts in 12
samples. Given the variability associated with Cryptosporidium
analytical methods, the Advisory Committee did not support requiring
additional treatment for filtered systems based on so few counts.
Another concern related to analytical method limitations was
systems being misclassified in a lower bin. For example, if a system
had a true mean concentration at or just above 0.1 oocysts/L, the mean
that the system would determine through monitoring might be less than
0.1 oocyst/L. Thus, if the bin threshold for additional treatment was
set at 0.1 oocysts/L, a number of systems with true mean concentrations
above this level would be misclassified in the lower bin with no
additional treatment required. This type of error, described in more
detail in the next section, is a function of the number of samples
collected and variability in method performance.
In consideration of the available information on Cryptosporidium
risk, as well as the performance and feasibility of analytical methods,
EPA is proposing that the source water threshold concentration for
requiring additional Cryptosporidium treatment by filtered systems be
established at a mean level of 0.075 oocysts/L. This is the level
recommended by the Advisory Committee, and it affords a high likelihood
that systems with true mean Cryptosporidium concentrations of 0.1
oocysts/L or higher will provide additional treatment under the rule.
Beyond identifying this first threshold, it was also necessary to
determine Cryptosporidium concentrations that would demarcate higher
risk bins. With respect to the concentration range that each bin should
comprise, EPA and the Advisory Committee dealt with two opposing
factors: bin misclassification and equitable risk reduction.
As described in the next section, a monthly monitoring program
involving EPA Methods 1622 or 1623 can characterize a system's mean
Cryptosporidium concentration within a

[[Page 47671]]

0.5 log (factor of 3.2) margin with a high degree of accuracy. However,
the closer a system's true mean concentration is to a bin boundary, the
greater the likelihood that the system will be misclassified into the
wrong bin due to limitations in sampling and analysis. Accordingly, by
establishing bins that cover a wide concentration range, the likelihood
of system misclassification is reduced.
However, a converse factor relates to equitable protection from
risk. Because identical treatment requirements will apply to all
systems in the same bin, systems at the higher concentration end of a
bin will achieve less risk reduction relative to their source water
pathogen levels than systems at the lower concentration end of a bin.
Thus, bins with a narrow concentration range provide a more uniform
level of public health protection.
In balancing these factors and to account for the wide range of
possible source water concentrations among different systems as
indicated by Information Collection Rule and ICRSS data, the Advisory
Committee recommended and EPA is proposing a second bin threshold at a
mean level of 1.0 oocysts/L and a third bin threshold at a mean level
of 3.0 oocysts/L. Information Collection Rule and ICRSS data indicate
that few, if any, systems would measure mean Cryptosporidium
concentrations greater than 3.0 oocysts/L, so there was not a need to
establish a bin threshold above this value. Thus, the LT2ESWTR proposal
includes the following four bins for classifying filtered systems: Bin
1: <0.075/L; Bin 2: =0.075 to <1.0/L; Bin 3:
=1.0/L to <3.0/L; and Bin 4: =3.0/L (oocysts/L).
With respect to additional Cryptosporidium treatment for systems in
Bins 2-4, values were considered ranging from 0.5 to 2.5 log and
greater. As recommended by the Advisory Committee, EPA is proposing 1.0
log additional treatment for conventional plants in Bin 2. This level
of treatment will ensure that systems classified in Bin 2 will achieve
treated water Cryptosporidium levels comparable to systems in Bin 1,
the lowest risk bin. In contrast, if systems in Bin 2 provided only 0.5
log additional treatment then those systems with mean source water
concentrations in the upper part of Bin 2 would have higher levels of
Cryptosporidium in their finished water than systems in Bin 1.
In consideration of the much greater potential vulnerability of
systems in the highest risk bins, the Advisory Committee recommended
additional treatment requirements of 2.0 log and 2.5 log for
conventional plants in Bins 3 and 4, respectively. The Agency concurs
with these recommendations and has incorporated them in today's
proposal.
An important aspect of the proposed additional treatment
requirements is that they are based, in part, on the current level of
treatment provided by filtration plants. As noted earlier, the Advisory
Committee assumed when developing its recommendations that conventional
treatment plants in compliance with the IESWTR achieve an average of 3
log removal of Cryptosporidium. EPA has determined that available data,
discussed in section III.D, support this assumption and has proposed a
3 log Cryptosporidium treatment credit for conventional plants under
the LT2ESWTR. Thus, the additional treatment requirements for
conventional plants in Bins 2, 3, and 4 translate to total requirements
of 4.0, 5.0, and 5.5 log, respectively.
The Advisory Committee did not address additional treatment
requirements for plants with treatment trains other than conventional,
but recommended that EPA address such plants in the proposed LT2ESWTR
and take comment. Based on treatment studies summarized in section
III.D, EPA has concluded that plants with slow sand or DE filtration
are able to achieve 3 log or greater removal of Cryptosporidium when in
compliance with the IESWTR or LT1ESWTR. Because these plants can
achieve comparable levels of performance to conventional treatment
plants, EPA is proposing that slow sand and DE filtration plants also
apply 1 to 2.5 log of additional treatment when classified in Bins 2-4.
Direct filtration differs from conventional treatment in that it
does not include sedimentation or an equivalent clarification process
prior to filtration. As described in section III.D, EPA has concluded
that a sedimentation process can consistently achieve 0.5 log or
greater removal of Cryptosporidium. The Agency is proposing that direct
filtration plants in compliance with the IESWTR or LT1ESWTR receive a
2.5 log Cryptosporidium removal credit towards LT2ESWTR requirements.
Accordingly, proposed additional treatment requirements for direct
filtration plants in bins 2, 3, and 4 are 1.5 log, 2.5 log, and 3 log,
respectively.
Section IV.C of this notice describes proposed criteria for
determining Cryptosporidium treatment credits for other filtration
technologies like membranes, bag filters, and cartridge filters. Due to
the proprietary and product specific nature of these filtration
devices, EPA is not able to propose a generally applicable credit for
them. Rather, the criteria in section IV.C focus on challenge testing
to establish treatment credit. Systems using these technologies that
are classified in Bins 2-4 must work with their States to assess
appropriate credit for their existing treatment trains. This will
determine the level of additional treatment necessary to achieve the
total treatment requirements for their assigned bins. EPA has developed
guidance on challenge testing of bag and cartridge filters and
membranes, which is available in draft form in the docket (http://
www.epa.gov/edocket/).
In order to give systems flexibility in choosing strategies to meet
additional Cryptosporidium treatment requirements, the Advisory
Committee identified a number of management and treatment options,
collectively called the microbial toolbox. The toolbox, which is
described in section IV.C, contains components relating to watershed
control, intake management, pretreatment, additional filtration
processes, inactivation, and demonstrations of enhanced performance.
As recommended by the Advisory Committee, EPA is proposing that
systems in Bin 2 can meet additional Cryptosporidium treatment
requirements under the LT2ESWTR using any component or combination of
components from the microbial toolbox. However, systems in Bins 3 and 4
must achieve at least 1 log of the additional treatment requirement
using inactivation (UV, ozone, chlorine dioxide), membranes, bag
filters, cartridge filters, or bank filtration. These specific control
measures are proposed due to their ability to serve as significant
additional treatment barriers for systems with high levels of
pathogens.
c. Basis for source water monitoring requirements. The goal of
monitoring under the LT2ESWTR is to correctly classify filtration
plants into the four LT2ESWTR risk bins. The proposed sampling
frequency, time frame, and averaging procedure for bin classification
are intended to ensure that systems are accurately assigned to
appropriate risk bins while limiting the burden of monitoring costs.
The basis for the proposed monitoring requirements for large and small
systems is presented in the following discussion.
i. Systems serving at least 10,000 people.
Sample Number and Frequency
Systems serving at least 10,000 people have two options for
sampling under the

[[Page 47672]]

LT2ESWTR: (1) They can collect 24 monthly samples over a 2 year period
and calculate their bin classification using the highest 12 month
running annual average, or (2) They can collect 2 or more samples per
month over the 2 year period and use the mean of all samples for bin
classification.
These proposed requirements reflect recommendations by the Advisory
Committee and are based on analyses of misclassification rates
associated with different monitoring programs that were considered. EPA
is concerned about systems with high concentrations of Cryptosporidium
being misclassified in lower bins as well as systems with low
concentrations being misclassified in higher bins. The first type of
error could lead to systems not providing an adequate level of
treatment while the second type of error could lead to systems
incurring additional costs for unnecessary treatment.
A primary way that EPA analyzed misclassification rates was by
considering the likelihood that a system with a true mean
Cryptosporidium concentration that is a factor of 3.2 (0.5 log) above
or below a bin boundary would be assigned to the wrong bin.
Probabilities were assessed for two cases:
[sbull] False negative: a system with a mean concentration of 0.24
oocysts/L (i.e., factor of 3.2 above the Bin 1 boundary of 0.075
oocysts/L) is misclassified low in Bin 1.
[sbull] False positive: a system with a mean concentration of 0.024
oocysts/L (i.e., factor of 3.2 below the Bin 1 boundary of 0.075
oocysts/L) is misclassified high in Bin 2.
Table IV-6 provides false negative and false positive rates as
defined previously for different approaches to monitoring and bin
classification that were evaluated. Results are shown for the following
approaches:
[sbull] 48 samples with bin assignment based on arithmetic mean
(i.e., average of all samples).
[sbull] 24 samples with bin assignment based on highest 12 sample
average, equivalent to the maximum running annual average (Max-RAA).
[sbull] 24 samples with bin assignment based on arithmetic mean.
[sbull] 12 samples with bin assignment based on the second highest
sample result.
[sbull] 8 samples with bin assignment based on the maximum sample
result.
These estimated misclassification rates were generated with a Monte
Carlo analysis that accounted for the volume assayed, variation in
source water Cryptosporidium occurrence, and variable method recovery.
See Economic Analysis for the LT2ESWTR (USEPA 2003a) for details.

Table IV-6.--False Positive and False Negative Rates for Monitoring and
Binning Strategies Considered for the LT2ESWTR
[In percentages]
------------------------------------------------------------------------
False False
Strategy positive negative
\1\ \2\
------------------------------------------------------------------------
48 sample arithmetic mean........................... 1.7 1.4
24 sample Max-RAA................................... 5.3 1.7
24 sample arithmetic mean........................... 2.8 6.2
12 sample second highest............................ 47 1.1
8 sample maximum.................................... 66 1.0
------------------------------------------------------------------------
\1\ False positive rates calculated for systems with Cryptosporidium
concentrations 0.5 log below the Bin 1 boundary of 0.075 oocysts/L.
\2\ False negative rates calculated for systems with Cryptosporidium
concentrations 0.5 log above the Bin 1 boundary of 0.075 oocysts/L.

The first two of these approaches, the 48 sample arithmetic mean
and 24 sample Max-RAA, were recommended by the Advisory Committee and
are proposed for bin classification under the LT2ESWTR because they
have low false positive and false negative rates. As shown in Table IV-
6, these strategies have false negative rates of 1 to 2%, meaning there
is a 98 to 99% likelihood that a plant with an oocyst concentration 0.5
log above the Bin 1 boundary would be correctly assigned to Bin 2. The
false positive rate is near 2% for the 48 sample arithmetic mean and 5%
for the 24 sample Max-RAA. These rates indicate that a plant with an
oocyst concentration 0.5 log below the Bin 1 boundary would have a 95
to 98% probability of being correctly assigned to Bin 1. Bin
misclassification rates across a wide range of concentrations are shown
in Economic Analysis for the LT2ESWTR (USEPA 2003a).
The 24 sample arithmetic mean had a slightly lower false positive
rate than the 24 sample Max-RAA (2.8% vs. 5.3%) but the false negative
rate of the arithmetic mean was almost 4 times higher. Consequently, a
plant with a mean Cryptosporidium level above the Bin 1 boundary would
be much more likely to be misclassified in Bin 1 using a 24 sample
arithmetic mean than with a 24 sample Max-RAA. In order to increase the
probability that systems with mean Cryptosporidium concentrations above
0.075 oocysts/L will provide additional treatment, EPA is proposing
that if only 24 samples are taken, the maximum 12 month running annual
average must be used to determine bin assignment.
Monitoring strategies involving only 12 and 8 samples were
evaluated to determine if lower frequency monitoring could provide
satisfactory bin classification. The results of this analysis indicate
that these lower sample numbers are not adequate and could unfairly
bias excessive treatment requirements. For example, results in Table
IV-6 show that if plants were classified in bins based on the second
highest of 12 samples or the highest of eight samples then low false
negative rates could be achieved. A system with a mean Cryptosporidium
level 0.5 log above the Bin 1 boundary would have a 99% chance of being
appropriately classified in a bin requiring additional treatment under
either strategy. However, the false positive rates associated with
these low sample numbers are very high. A system with a mean oocyst
concentration 0.5 log below the Bin 1 boundary would have a 47%
probability of being incorrectly classified in Bin 2 using the second
highest result among 12 samples, or a 66% likelihood of being
misclassified in Bin 2 using the maximum result among 8 samples. Due to
high false positive rates, these strategies are not proposed.
EPA also evaluated lower frequency monitoring strategies that had
lower false positive rates, such as bin classification based on the
mean of 12 samples, the third highest result of 12 samples, and the
second highest of 8 samples. Each of these strategies, though, had an
unacceptably high false negative rate, meaning that many systems with
mean oocyst concentrations greater than the Bin 1 boundary would be
misclassified low in Bin 1. Consequently, these strategies are
inconsistent with the public health goal of the LT2ESWTR for systems
with mean levels above 0.075 oocysts/L to provide additional treatment.
Increasing the number of samples used to compute the maximum
running annual average above 24 also increased the number of annual
averages computed, so it did not reduce the likelihood of false
positives. Raising the number of samples used to compute an arithmetic
mean above 48 did reduce bin misclassification rates, but the rates
were already very small (1 to 2% for plants with levels 0.5 log above
or below bin boundaries). For sources with Cryptosporidium
concentrations very near or at bin boundaries, increasing the number of
samples did not markedly improve the error rates, which remained near
50% at the bin boundaries.
In summary, EPA believes that the proposed sampling designs perform
well for the purpose of classifying plants in LT2ESWTR risk bins and,

[[Page 47673]]

thereby, achieving the public health protection intended for the rule.
More costly designs, involving more frequent sampling and analysis,
provide only marginally improved performance. Less frequent sampling,
though lower in cost, creates unacceptably high misclassification rates
and would not provide for the targeted risk reduction goals of the
rule.
No Adjustments for Method Recovery or Percent of Oocysts That Are
Infectious
Two considerations in using Cryptosporidium monitoring data to
project risk are (1) Fewer than 100% of oocysts in a sample are
recovered and counted by the analyst and (2) not all the oocysts
measured with Methods 1622/23 are viable and capable of causing
infection. These two factors are offsetting in sign, in that oocyst
counts not adjusted for recovery tend to underestimate the true
concentration, while the total oocyst count may overestimate the
infectious concentration that presents a health risk. Based on
information described in this section, EPA is proposing that
Cryptosporidium monitoring results be used directly to assign systems
to LT2ESWTR risk bins and not be adjusted for either factor.
As described in section III.C, ICRSS matrix spike data indicate
that average recovery of Cryptosporidium oocysts with Methods 1622/23
in a national monitoring program will be about 40%. There is no similar
direct measure of the fraction of environmental oocysts that are
infectious, but information related to this value can be derived from
two sources: (1) A study where samples were analyzed with both Method
1623 and a cell culture-polymerase chain reaction (CC-PCR) test for
oocyst infectivity, and (2) the structure of oocysts counted with
Methods 1622 and 1623.
LeChevallier et al. (2003) conducted a study in which six natural
waters were frequently tested for Cryptosporidium using both Method
1623 and a CC-PCR method to test for infectivity. Cryptosporidium
oocysts were detected in 60 of 593 samples (10.1%) by Method 1623 and
infectious oocysts were detected in 22 of 560 samples (3.9%) by the CC-
PCR procedure. Recovery efficiencies for the two methods were similar.
According to the authors, these results suggest that approximately 37%
(22/60) of the Cryptosporidium oocysts detected by Method 1623 were
viable and infectious.
In regard to oocyst structure, Cryptosporidium oocysts counted with
Methods 1622/23 are characterized in one of three ways: (1) Internal
structures, (2) amorphous structures, or (3) empty. Oocysts with
internal structures are considered to have the highest likelihood of
being infectious, while empty oocysts are believed to be non-viable
(LeChevallier et al. 1997). During the ICRSS, 37% of the oocysts
counted were characterized as having internal structures, 47% had
amorphous structures, and 16% were empty. If it is assumed that empty
oocysts could not be infectious, the mid-point value within the
percentage range of counted oocysts that could have been infectious is
42%.
After considering this type of information, the Advisory Committee
recommended that monitoring results not be adjusted upward for percent
recovery, nor adjusted downward to account for the fraction of oocysts
that are not infectious. While it is not possible to establish a
precise value for either factor in individual samples, the data suggest
that they may be of similar magnitude. EPA concurs with this
recommendation and is proposing that systems be classified in bins
under the LT2ESWTR using the total Cryptosporidium oocyst count,
uncorrected for recovery, as measured using EPA Method 1622/23. The
proposed LT2ESWTR risk bins are constructed to reflect this approach.
Data Collection To Support Use of a Microbial Indicator by Small
Systems
As described in the next section, small systems will monitor for an
indicator, currently proposed to be E. coli, to determine if they are
required to sample for Cryptosporidium. The proposed E. coli levels
that will trigger Cryptosporidium monitoring are based on Information
Collection Rule and ICRSS data. However, to provide for a more
extensive evaluation of Cryptosporidium indicator criteria, EPA is
proposing that large systems measure E. coli and turbidity in their
source water when they sample for Cryptosporidium. This was recommended
by the Advisory Committee and will allow for possible development of
alternative indicator levels or parameters (e.g., turbidity in
combination with E. coli) to serve as triggers for small system
Cryptosporidium monitoring.
Time Frame for Monitoring
In recommending a time frame for LT2ESWTR monitoring, the Agency
considered the trade-off between monitoring over a long period to
better capture year-to-year fluctuations, and the desire to prescribe
additional treatment quickly to systems identified as having high
source water pathogen levels. Reflecting Advisory Committee
recommendations, EPA is proposing that large systems evaluate their
source water Cryptosporidium levels using 2 years of monitoring. This
will account for some degree of yearly variability, without
significantly delaying additional public health protection where
needed.
ii. Systems serving fewer than 10,000 people.
Indicator Monitoring
In recognition of the relatively high cost of analyzing samples for
Cryptosporidium, EPA and the Advisory Committee explored the use of
indicator criteria to identify drinking water sources that may have
high levels of Cryptosporidium occurrence. The goal was to find one or
more parameters that could be analyzed at low cost and identify those
systems likely to exceed the Bin 1 boundary of 0.075 oocysts/L. Data
from the Information Collection Rule and ICRSS were evaluated for
possible indicator parameters, including fecal coliforms, total
coliforms, E. coli, viruses (Information Collection Rule only), and
turbidity. Based on available data, E. coli was found to provide the
best performance as a Cryptosporidium indicator, and the inclusion of
other parameters like turbidity was not found to improve accuracy.
The next part of this section presents data that support E. coli
mean concentrations of 10/100 mL and 50/100 mL as proposed screening
levels that will trigger Cryptosporidium monitoring in reservoir/lake
and flowing stream systems, respectively. It describes how E. coli and
Cryptosporidium data from the Information Collection Rule and ICRSS
were analyzed and shows the performance of different concentrations of
E. coli as an indicator for systems that will exceed the Bin 1 boundary
of 0.075 oocysts/L.
Information Collection Rule data were evaluated as maximum running
annual averages (Information Collection Rule samples were collected
once per month for 18 months) while ICRSS data were evaluated using an
annual mean (ICRSS samples were collected twice per month for 12
months). In addition, as indicators were being evaluated it became
apparent that it was necessary to analyze plants separately based on
source water type, due to a significantly different relationship
between E. coli and Cryptosporidium in reservoir/lake systems compared
to flowing stream systems.
Analyzing the performance of an E. coli level as a screen to
trigger Cryptosporidium monitoring under the proposed LT2ESWTR involved

[[Page 47674]]

evaluating each water treatment plant in the data set relative to two
factors: (1) Did the plant E. coli level exceed the trigger value being
assessed? and (2) Did the plant mean Cryptosporidium concentration
exceed 0.075 oocysts/L? Accordingly, plants were sorted into four
categories, based on Cryptosporidium and E. coli concentrations:
[sbull] Plants with Cryptosporidium < 0.075 oocysts/L that did not
exceed the E. coli trigger level (Figure IV-1, box A)
[sbull] Plants with Cryptosporidium < 0.075 oocysts/L that exceeded
the E. coli trigger level (Figure IV.1, box B)
[sbull] Plants with Cryptosporidium = 0.075 oocysts/L
that did not exceed the E. coli trigger level (Figure IV.1, box C)
[sbull] Plants with Cryptosporidium = 0.075 oocysts/L
that exceeded the E. coli trigger level (Figure IV.1, box D)

Summary data with E. coli trigger concentrations ranging from 5 to 100
per 100 mL are presented for Information Collection Rule and ICRSS data
in Figures IV-2 and IV-3.
The performance of each E. coli level as a trigger for
Cryptosporidium monitoring was evaluated based on false negative and
false positive rates. False negatives occur when plants do not exceed
the E. coli trigger value, but exceed a Cryptosporidium level of 0.075
oocysts/L. False positives occur when plants exceed the E. coli trigger
value but do not exceed a Cryptosporidium level of 0.075 oocysts/L. The
false negative rate is critical because it characterizes the ability of
the indicator to identify those plants with high Cryptosporidium
levels. In general, low false negative rates can be achieved by
lowering the E. coli trigger concentration. However, when the E. coli
trigger concentration is decreased, more plants with low
Cryptosporidium levels in their source water exceed it. As a result,
more plants incur false positives. Consequently, identifying an
appropriate E. coli concentration to trigger Cryptosporidium monitoring
involves balancing false negatives and false positives to minimize
both.
Results of the indicator analysis for plants with flowing stream
sources are shown in Figure IV-2. An E. coli trigger concentration of
50/100 mL produced zero false negatives for both data sets. This means
that in these data sets, all plants that exceeded mean Cryptosporidium
concentrations of 0.075 oocysts/L also exceeded the E. coli trigger
concentration and would, therefore, be required to monitor. However,
this trigger concentration had a significant false positive rate (i.e.,
it was not highly specific in targeting only those plants with high
Cryptosporidium levels). False positive rates were 57% (24/42) and 53%
(9/17) with Information Collection Rule and ICRSS data, respectively.
At a higher E. coli trigger concentration, such as 100/100 mL, the
false negative rate increased to 12.5% (3/24) with Information
Collection Rule data and 50% (2/4) with ICRSS data, while the false
positive rate decreased to 43% (18/42) and 35% (6/17), respectively.
Consequently, EPA is proposing a mean E. coli concentration of 50/100
mL as a trigger for Cryptosporidium monitoring by small systems with
flowing stream sources.
Results of the indicator analysis for plants with reservoir/lake
sources are shown in Figure IV-3. An E. coli trigger of 10/100 mL
resulted in a false negative rate of 20% (2/10) with Information
Collection Rule data and 67% (2/3) with ICRSS data (misclassified 2 out
of 3 plants over 0.075 oocysts/L). Going to a lower concentration E.
coli trigger, such as 5 per 100 mL, decreased the false negative rate
in both the Information Collection Rule and ICRSS data sets by one
plant, but increased the false positive rate from 20% to 43% (13/30) in
the ICRSS data and from 24% to 39% (44/114) in the Information
Collection Rule data. Based on these results, EPA is proposing that a
mean E. coli concentration of 10/100 mL trigger small systems using
lake/reservoir sources into monitoring for Cryptosporidium. While the
false negative rate associated with this trigger value in the ICRSS
data set is high, the ICRSS data set contains only 3 reservoir/lake
plants that exceeded a Cryptosporidium level of 0.075 oocysts/L.
Due to limitations in the available data, the Advisory Committee
did not recommend that large systems use the E. coli indicator screen,
as Cryptosporidium monitoring is less of an economic burden for large
systems. Rather, the Advisory Committee recommended that large systems
sample for E. coli and turbidity when they monitor for Cryptosporidium
under the LT2ESWTR. These data will then be used to verify or, if
necessary, further refine the proposed indicator trigger values for
small systems. EPA concurs with these recommendations and they are
reflected in today's proposal.
The proposed monitoring schedule under the LT2ESWTR is set up to
allow EPA and stakeholders to evaluate large system monitoring data for
indicator relationships prior to the start of small system E. coli
monitoring. After one year of large system monitoring is completed, EPA
will begin analyzing monitoring data to assess whether alternative
indicator strategies would be appropriate. Depending on the findings of
this analysis, EPA may issue guidance to States on approving
alternative indicator trigger strategies for small systems. Therefore,
the proposed rule is written with the allowance for States to approve
alternative indicator strategies.
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BILLING CODE 6560-50-C

Cryptosporidium Monitoring

Small systems that exceed the E. coli trigger must conduct
Cryptosporidium monitoring, beginning 6 months after completion of E.
coli monitoring. As recommended by the Advisory Committee, EPA is
proposing that small systems collect 24 Cryptosporidium samples over a
period of one year. This number of samples is the same as required for
large systems, but the monitoring burden is targeted only on those
plants that E. coli monitoring indicates to have elevated levels of
fecal matter in the source water. By completing Cryptosporidium
monitoring in one year, small systems will conduct a total of 2 years
of monitoring to determine LT2ESWTR bin classification (including the
one year of E. coli monitoring). This time frame is equivalent to the
requirement for large systems, which monitor for Cryptosporidium, E.
coli, and turbidity for 2 years.
The Stage 2 M-DBP Agreement in Principle recommended that EPA
explore the feasibility of alternative, lower frequency,
Cryptosporidium monitoring criteria for providing a conservative mean
estimate in small systems. As described earlier, EPA has evaluated
smaller sample sizes, such as systems taking 12 or 8 samples instead of
24 (see Table IV-6). However, EPA has concluded that these smaller
sample sizes result in unacceptably high misclassification rates. For
example, bin classification based on the second highest of 12 samples
produces an estimated false positive rate of 47% for systems with a
mean Cryptosporidium concentration 0.5 log below the Bin 1 boundary of
0.075/L. In comparison, bin classification based on the mean of 24
samples achieves a false positive rate of 2.8% for systems at this
Cryptosporidium concentration. Consequently, EPA is proposing no
alternatives to the requirement that small systems take at least 24
samples.
Small system bin classification will be determined by the
arithmetic mean of the 24 samples collected over one year. Because the
bin structure in the LT2ESWTR is based on annual mean Cryptosporidium
levels, it is necessary that bin classification involve averaging
samples over at least one year. Consequently, small systems will
determine their bin classification by averaging results from all
Cryptosporidium samples collected during their one year of monitoring.
iii. Future monitoring and reassessment. EPA is proposing that
beginning 6 years after the initial bin classification, large and small
systems conduct another round of monitoring to determine if source
water conditions have changed to a degree that may warrant a revised
bin classification. The Advisory Committee recommended that EPA convene
a stakeholder process within 4 years after the initial bin
classification to develop recommendations on how best to proceed with
implementing this second round of monitoring. Unless EPA modifies the
LT2ESWTR to allow for an improved analytical method or a revised bin
structure based on new risk information, the second round of monitoring
will be conducted under the same requirements that apply to the initial
round of monitoring.
In addition, EPA is proposing to use the required assessment of the
water source during sanitary surveys as an ongoing measure of whether
significant changes in watersheds have occurred that may lead to
increased contamination. Where the potential for increased
contamination is identified, States must determine what follow-up
actions by the system are necessary, including the possibility of the
system providing additional treatment from the microbial toolbox.
d. Basis for accepting previously collected data. Members of the
Advisory Committee had multiple objectives in recommending that EPA
allow the use of previously collected (grandfathered) Cryptosporidium
data. These include (1) giving credit for data collected by proactive
utilities, (2) facilitating early determination of LT2ESWTR compliance
needs and, thereby, allowing for early planning of appropriate
treatment selection, (3) increasing laboratory capacity to meet demand
for Cryptosporidium analysis under the LT2ESWTR, and (4) allowing
utilities to improve their data set for bin determination by
considering more than 2 years of data (i.e., include data collected
prior to effective date of LT2ESWTR). The latter objective incorporates
the assumption that occurrence can vary from year to year, so that if
more years of data are used in the bin determination, the source water
concentration estimate will be a more accurate representation of the
overall mean.
A significant issue with accepting previously collected data for
making bin determinations is ensuring that the data are of equivalent
quality to data that will be collected following LT2ESWTR promulgation.
As noted previously, EPA is establishing requirements so that data
collected under the LT2ESWTR will be similar in quality to data that
were generated under the ICRSS. These requirements include the use of
approved analytical methods and compliance with method quality control
(QC) criteria, use of approved laboratories, minimum sample volume, and
a sampling schedule with minimum frequency. For example, under the
ICRSS, laboratories analyzed 10 L samples and (considered collectively)
achieved a mean Cryptosporidium recovery of approximately 43% in spiked
source water with a relative standard deviation (RSD) of 50%. EPA
anticipates that laboratories conducting Cryptosporidium analysis for
the LT2ESWTR will collectively achieve similar analytical method
performance. Consequently, EPA expects previously collected data sets
used under the LT2ESWTR to meet these standards and has established
criteria for accepting previously collected data accordingly (see
section IV.A.1.d).
Systems are requested, but not required, to notify EPA prior to
promulgation of the LT2ESWTR of their intent to submit previously
collected data. This will help EPA allocate the resources that will be
needed to evaluate these data in order to make a decision on adequacy
for bin determination. Systems that have at least 2 years of previously
collected data to grandfather when the LT2ESWTR is promulgated and do
not intend to conduct new monitoring under the rule are required to
submit the previously collected data to EPA within 2 months following
promulgation. This will enable EPA to evaluate the data and report back
to the utility in sufficient time to allow, if needed, the utility to
contract with a laboratory to conduct monitoring under the LT2ESWTR.
Systems that have fewer than 2 years of previously collected data
to grandfather when the LT2ESWTR is promulgated, or that intend to
grandfather 2 or more years of previously collected data and also
conduct new monitoring under the rule, are required to submit the
previously collected data to EPA within 8 months following
promulgation. This will allow these utilities to continue to collect
previously collected data in the 6 month period between promulgation
and the date when monitoring under the LT2ESWTR must begin, plus a 2
month period for systems to compile the data and supporting
documentation. Utilities may submit the data earlier than 8 months
after promulgation if they acquire 2 years of previously collected data
before this date.
Submitted grandfathered data sets must include all routine source
water monitoring results for samples collected during the time period
covered by the

[[Page 47678]]

grandfathered data set (i.e., the time period between collection of the
first and last samples in the data set). However, systems are not
required under the LT2ESWTR to submit previously collected data for
samples outside of this time period.
3. Request for Comment
EPA requests comments on all aspects of the monitoring and
treatment requirements proposed in this section. In addition, EPA
requests comment on the following issues:
Requirements for Systems That Use Surface Water for Only Part of the
Year
Bin classification for the LT2ESWTR is based on the mean annual
sourcewater Cryptosporidium level. Consequently, today's proposal
requires E. coli and Cryptosporidium monitoring to be conducted over
the full year. However, EPA recognizes that some systems use surface
water for only part of the year. This occurs with systems that use
surface water for part of the year (e.g., during the summer) to
supplement ground water sources and with systems like campgrounds that
are in operation for only part of the year. Year round monitoring for
these systems may present both logistic and economic difficulties. EPA
is requesting comment on how to apply LT2ESWTR monitoring requirements
to surface water systems that operate or use surface water for only
part of the year. Possible approaches that may be considered for
comment include the following:
Small public water systems that operate or use surface water for
only part of the year could be required to collect E. coli samples at
least bi-weekly during the period when they use surface water. If the
mean E. coli concentration did not exceed the trigger level (e.g., 10/
100 mL for reservoirs/lakes or 50/100mL for flowing streams), systems
could apply to the State to waive any additional E. coli monitoring.
The State could grant the waiver, require additional E. coli
monitoring, or require monitoring of an alternate indicator. If the
mean E. coli concentration exceeded the trigger level, the State could
require the system to provide additional treatment for Cryptosporidium
consistent with Bin 4 requirements, or require monitoring of
Cryptosporidium or an indicator, with the results potentially leading
to additional Cryptosporidium treatment requirements.
Large public water systems that operate or use surface water for
only part of the year could be required to collect Cryptosporidium
samples (along with E. coli and turbidity) either twice-per-month
during the period when they use surface water or 12 samples per year,
whichever is smaller. Samples would be collected during the two years
of the required monitoring period, and bin classification would be
based on the highest average of the two years.
EPA requests comment on these and other approaches for both small
and large systems.
Previously Collected Monitoring Data That Do Not Meet QC Requirements
EPA is proposing requirements for acceptance of previously
collected monitoring data that are equivalent to requirements for data
generated under the LT2ESWTR. The Agency is aware that systems will
have previously collected Cryptosporidium data that do not meet all
sampling and analysis requirements (e.g., quality control, sample
frequency, sample volume) proposed for data collected under the
LT2ESWTR. However, the Agency has been unable to develop an approach
for allowing systems to use such data for LT2ESWTR bin classification.
This is due to uncertainty regarding the impact of deviations from
proposed sampling and analysis requirements on data quality and
reliability. For example, Methods 1622 and 1623 have been validated
within the limits of the QC criteria specified in these methods. While
very minor deviations from required QA/QC criteria may have only a
minor impact on data quality, the Agency has not identified a basis for
establishing alternative standards for data acceptability.
EPA requests comment on whether or under what conditions previously
collected data that do not meet the proposed criteria for LT2ESWTR
monitoring data should be accepted for use in bin determination.
Specifically, EPA requests comment on the sampling frequency
requirement for previously collected data, and whether EPA should allow
samples collected at lower or varying frequencies to be used as long as
the data are representative of seasonal variation and include the
required number of samples. If so, how should EPA determine whether
such a data set is unbiased and representative of seasonal variation?
How should data collected at varying frequency be averaged?
Monitoring for Systems That Recycle Filter Backwash
Plants that recycle filter backwash water may, in effect, increase
the concentration of Cryptosporidium in the water that enters the
filtration treatment train. Under the LT2ESWTR proposal, microbial
sampling may be conducted on source water prior to the addition of
filter backwash water. EPA requests comment on how the effect of
recycling filter backwash should be considered in LT2ESWTR monitoring.
Bin Assignment for Systems That Fail To Complete Required Monitoring
Today's proposal classifies systems that fail to complete required
monitoring in Bin 4, the highest treatment bin. EPA requests comment on
alternative approaches for systems that fail to complete required
monitoring, such as classifying the system in a bin based on data the
system has collected, or classifying the system in a bin one level
higher than the bin indicated by the data the system has collected. The
shortcoming to these alternative approaches is that bin classification
becomes more uncertain, and the likelihood of bin misclassification
increases, as systems collect fewer than the required 24
Cryptosporidium samples. Consequently, the proposed approach is for
systems to collect all required samples.
Note that under today's proposal, systems may provide 5.5 log of
treatment for Cryptosporidium (i.e., comply with Bin 4 requirements) as
an alternative to monitoring. Where systems notify the State that they
will provide treatment instead of monitoring, they will not incur
monitoring violations.
Monitoring Requirements for New Plants and Sources
The proposed LT2ESWTR would establish calendar dates when the
initial and second round of source water monitoring must be conducted
to determine bin classification. EPA recognizes that new plants will
begin operation, and that existing plants will access new sources,
after these dates. EPA believes that new plants and plants switching
sources should conduct monitoring equivalent to that required of
existing plants to determine the required level of Cryptosporidium
treatment. The monitoring could be conducted before a new plant or
source is brought on-line, or initiated within some time period
afterward. EPA requests comment on monitoring and treatment
requirements for new plants and sources.
Determination of LT2ESWTR Bin Classification
In today's proposal, EPA expects that systems will be assigned to
LT2ESWTR risk bins based on their reported Cryptosporidium monitoring
results and the calculations proposed for bin

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assignment described in this section. EPA requests comment on whether
bin classifications should formally be made or reviewed by States.
Source Water Type Classification for Systems That Use Multiple Sources
In today's proposal, the E. coli concentrations that trigger small
system Cryptosporidium monitoring are different for systems using lake/
reservoir and flowing stream sources. However, EPA recognizes that some
systems use multiple sources, potentially including both lake/reservoir
and flowing stream sources, and that the use of different sources may
vary during the year. Further, some systems use sources that are ground
water under the direct influence (GWUDI) of surface water. EPA requests
comment on how to apply the E. coli criteria for triggering
Cryptosporidium monitoring to systems using multiple sources and GWUDI
sources.

B. Unfiltered System Treatment Technique Requirements for
Cryptosporidium

1. What Is EPA Proposing Today?
a. Overview. EPA is proposing treatment technique requirements for
Cryptosporidium in unfiltered systems. Today's proposal requires all
unfiltered systems using surface water or ground water under the direct
influence of surface water to achieve at least 2 log (99%) inactivation
of Cryptosporidium prior to the distribution of finished water.
Further, unfiltered systems must monitor for Cryptosporidium in their
source water, and where monitoring demonstrates a mean level above 0.01
oocysts/L, systems must provide at least 3 log Cryptosporidium
inactivation. Disinfectants that can be used to meet this treatment
requirement include ozone, ultraviolet (UV) light, and chlorine
dioxide.
All current requirements for unfiltered systems under 40 CFR 141.71
and 141.72(a) remain in effect, including requirements to inactivate at
least 3 log of Giardia lamblia and 4 log of viruses. In addition,
unfiltered systems must meet their overall disinfection requirements
using a minimum of two disinfectants. These proposed requirements
reflect recommendations of the Stage 2 M-DBP Federal Advisory
Committee. Details of the proposed requirements are described in the
following sections.
b. Monitoring requirements. Requirements for Cryptosporidium
monitoring by unfiltered systems are similar to requirements for
filtered systems of the same size, as given in section IV.A.1.
Unfiltered systems serving at least 10,000 people must sample their
source water for Cryptosporidium at least monthly for two years,
beginning no later than 6 months after promulgation of this rule.
Samples may be collected more frequently (e.g., semi-monthly, weekly)
as long as a consistent frequency is maintained throughout the
monitoring period.
Unfiltered systems serving fewer than 10,000 people must conduct
source water sampling for Cryptosporidium at least twice-per-month for
one year, beginning no later than 4 years following promulgation of
this rule (i.e., on the same schedule as small filtered systems).
However, unlike small filtered systems, small unfiltered systems cannot
monitor for an indicator (e.g., E. coli) to determine if they are
required to monitor for Cryptosporidium. EPA has not identified
indicator criteria that can effectively screen for plants with
Cryptosporidium concentrations below 0.01 oocysts/L. Consequently, all
small unfiltered systems must conduct Cryptosporidium monitoring.
As described in section IV.K and IV.L, Cryptosporidium analyses
must be performed on at least 10 L per sample with EPA Methods 1622 or
1623, and must be conducted by laboratories approved for these methods
by EPA. Analysis of larger sample volumes is allowed, provided the
laboratory has demonstrated comparable method performance to that
achieved on a 10 L sample. Section IV.J describes requirements for
reporting sample analysis results. All Cryptosporidium samples must be
collected in accordance with a schedule that is developed by the system
and submitted to EPA or the State at least 3 months prior to initiation
of sampling. Refer to section IV.A.1 for requirements pertaining to any
failure to report a valid sample analysis result for a scheduled
sampling date and procedures for collecting a replacement sample.
Unfiltered systems are required to participate in future
Cryptosporidium monitoring on the same schedule as filtered systems of
the same size. Future monitoring requirements for filtered systems are
described in section IV.A.1.
Unfiltered systems are not required to conduct source water
Cryptosporidium monitoring under the LT2ESWTR if the system currently
provides or will provide a total of at least 3 log Cryptosporidium
inactivation, equivalent to meeting the treatment requirements for
unfiltered systems with a mean Cryptosporidium concentration of greater
than 0.01 oocysts/L. Systems must notify the State not later than the
date the system is otherwise required to submit a sampling schedule for
monitoring. Systems must install and operate technologies to provide a
total of at least 3 log Cryptosporidium inactivation by the applicable
date in Table IV-24.
c. Treatment requirements. All unfiltered systems must provide
treatment for Cryptosporidium, and the degree of required treatment
depends on the level of Cryptosporidium in the source water as
determined through monitoring. Unfiltered systems must calculate their
average source water Cryptosporidium concentration using the arithmetic
mean of all samples collected during the required two year monitoring
period (or one year monitoring period for small systems). For
unfiltered systems with mean source water Cryptosporidium levels of
less than or equal to 0.01 oocysts/L, 2 log Cryptosporidium
inactivation is required. Where the mean source water level is greater
than 0.01 oocysts/L, 3 log inactivation is required.
In addition, unfiltered systems are required to use at least two
different disinfectants to meet their overall inactivation requirements
for viruses (4 log), Giardia lamblia (3 log), and Cryptosporidium (2 or
3 log). Further, each of the two disinfectants must achieve by itself
the total inactivation required for one of these three pathogen types.
For example, a system could use UV light to achieve 2 log inactivation
of Cryptosporidium and Giardia lamblia, and use chlorine to inactivate
1 log Giardia lamblia and 4 log viruses. In this case, chlorine would
achieve the total inactivation required for viruses while UV light
would achieve the total inactivation required for Cryptosporidium, and
the two disinfectants together would meet the overall treatment
requirements for viruses, Giardia lamblia, and Cryptosporidium. In all
cases unfiltered systems must continue to meet disinfectant residual
requirements for the distribution system.
EPA has developed criteria, described in sections IV.C.14-15, for
systems to determine Cryptosporidium inactivation credits for chlorine
dioxide, ozone, and UV light. Unfiltered systems are allowed to use any
of these disinfectants to meet the 2 (or 3) log Cryptosporidium
inactivation requirement. The following paragraphs describe standards
for demonstrating compliance with the proposed Cryptosporidium
treatment technique requirement. For systems using ozone and chlorine
dioxide, these standards are similar to current standards for
compliance with Giardia

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lamblia and virus treatment requirements, as established by the SWTR in
40 CFR 141.72 and 141.74. However, for systems using UV light, modified
compliance standards are proposed, due to the different way in which UV
disinfection systems will be monitored.
Each day a system using ozone or chlorine dioxide serves water to
the public, the system must calculate the CT value(s) from the system's
treatment parameters, using the procedures specified in 40 CFR
141.74(b)(3). The system must determine whether this value(s) is
sufficient to achieve the required inactivation of Cryptosporidium
based on the CT criteria specified in section IV.C.14. The disinfection
treatment must ensure at least 99 percent (or 99.9 percent if required)
inactivation of Cryptosporidium every day the system serves water to
the public, except any one day each month. Systems are required to
report daily CT values on a monthly basis, as described in section
IV.J.
Each day a system using UV light serves water to the public, the
system must monitor for the parameters, including flow rate and UV
intensity, that demonstrate whether the system's UV reactors are
operating within the range of conditions that have been validated to
achieve the required UV dose, as specified in section IV.C.15. Systems
must monitor each UV reactor while in use and must record periods when
any reactor operates outside of validated conditions. The disinfection
treatment must ensure at least 99 percent (or 99.9 percent if required)
inactivation of Cryptosporidium in at least 95 percent of the water
delivered to the public every month. Systems are required to report
periods when UV reactors operate outside of validated conditions on a
monthly basis, as described in section IV.J.
Unfiltered systems currently must comply with requirements for DBPs
as a condition of avoiding filtration under 40 CFR 141.71(b)(6). As
described earlier, EPA is developing a Stage 2 DBPR, which will further
limit allowable levels of certain DBPs, specifically trihalomethanes
and haloacetic acids. EPA intends to incorporate new standards for DBPs
established under the Stage 2 DBPR into the criteria for filtration
avoidance.
2. How Was This Proposal Developed?
a. Basis for Cryptosporidium treatment requirements. The intent of
the proposed treatment requirements for unfiltered systems is to
achieve public health protection against Cryptosporidium equivalent to
filtration systems. As described in section III.C, an assessment of
survey data indicates that under current treatment requirements,
finished water Cryptosporidium levels are higher in unfiltered systems
than in filtered systems.
Information Collection Rule data show an average plant-mean
Cryptosporidium level of 0.59 oocysts/L in the source water of filtered
plants and 0.014 oocysts/L in unfiltered systems. Median plant-mean
concentrations were 0.052 and 0.0079 oocysts/L in filtered and
unfiltered system sources, respectively. Thus, these results suggest
that typical Cryptosporidium occurrence in filtered system sources is
approximately 10 times higher than in unfiltered system sources.
In translating these data to assess finished water risk, EPA and
the Advisory Committee estimated that conventional plants in compliance
with the IESWTR achieve an average Cryptosporidium removal of 3 log
(see discussion in section III.D). Hence, if the median source water
Cryptosporidium level at conventional plants is approximately 10 times
higher than at unfiltered systems, and it is estimated that
conventional plants achieve an average reduction of 3 log (99.9%), then
the median finished water Cryptosporidium concentration at conventional
plants is lower by a factor of 100 than at unfiltered systems.
Therefore, to ensure equivalent public health protection, unfiltered
systems should reduce Cryptosporidium levels by 2 log.
Due to the development of criteria for Cryptosporidium inactivation
with ozone, chlorine dioxide, and UV light, EPA has determined that it
is feasible for unfiltered systems to comply with a Cryptosporidium
treatment technique requirement. Consequently, EPA is proposing that
all unfiltered systems provide at least 2 log inactivation of
Cryptosporidium.
The proposed treatment requirements for unfiltered systems with
higher source water Cryptosporidium levels are consistent with proposed
treatment requirements for filtered systems. As discussed previously,
EPA is proposing that filtered plants with mean source water
Cryptosporidium levels between 0.075 and 1.0 oocysts/L, as measured by
Methods 1622 and 1623, provide at least a 4 log reduction (with greater
treatment required for higher source water pathogen levels). These
requirements will achieve average treated water Cryptosporidium
concentrations below 1 oocyst/10,000 L in filtered systems. An
unfiltered system with a mean source water Cryptosporidium
concentration above 0.01 oocyst/L would need to provide more than 2 log
inactivation in order to achieve an equivalent finished water oocyst
level. Therefore, EPA is proposing that unfiltered systems provide at
least 3 log inactivation where mean concentrations exceed 0.01 oocysts/
L.
For unfiltered systems using UV disinfection to meet these proposed
Cryptosporidium treatment requirements, EPA is proposing that
compliance be based on a 95th percentile standard (i.e., at least 95
percent of the water must be treated to the required UV dose). This
standard is intended to be comparable with the ``every day except any
one day per month'' compliance standard established by the SWTR for
chemical disinfection (see 40 CFR 141.72(a)(1)). Because UV
disinfection systems will typically consist of multiple parallel
reactors that will be monitored continuously, the Agency has determined
that it is more appropriate to base a compliance determination on the
percentage of water disinfected to the required level, rather than a
single daily measurement. The UV Disinfection Guidance Manual (USEPA
2003d) will provide advice on meeting this proposed standard. A draft
of this guidance is available in the docket for today's proposal
(http://www.epa.gov/edocket/).
b. Basis for requiring the use of two disinfectants. EPA is
proposing that unfiltered systems use at least two different
disinfectants to meet the 2 (or 3), 3, and 4 log inactivation
requirements for Cryptosporidium, Giardia lamblia, and viruses,
respectively. The purpose of this requirement is to provide for
multiple barriers of protection against pathogens. One benefit of this
approach is that if one barrier were to fail then there would still be
one remaining barrier to provide protection against some of the
pathogens that might be present. For example, if a plant used UV to
inactivate Cryptosporidium and Giardia lamblia, along with chlorine to
inactivate viruses, and the UV system were to malfunction, the chlorine
would still meet the treatment requirement for viruses and would
provide some degree of protection against Giardia lamblia.
Another benefit of multiple barriers is that they will typically
provide more effective protection against a broad spectrum of pathogens
than a single disinfectant. Because the efficacy of disinfectants
against different pathogens varies widely, using multiple disinfectants
will generally provide more efficient inactivation of a wide

[[Page 47681]]

range of pathogens than a single disinfectant.
EPA is aware, though, that this requirement would not result in a
redundant barrier for each type of pathogen. In the example of a plant
using chlorine and UV, the chlorine would provide essentially no
protection against Cryptosporidium and might achieve only a small
amount of Giardia lamblia inactivation if it was designed primarily to
inactivate viruses. However, since the watersheds of unfiltered systems
are required to be protected (40 CFR 141.71), the probability is low
that high levels of Cryptosporidium or Giardia lamblia would occur
during the time frame necessary to address a short period of treatment
failure.
Note the request for comment on this topic at the end of this
section.
c. Basis for source water monitoring requirements. Monitoring by
unfiltered systems is necessary to identify those with mean source
water Cryptosporidium levels above 0.01 oocysts/L. In order to allow
for simultaneous compliance with other microbial and disinfection
byproduct regulatory requirements, EPA is proposing that unfiltered
systems monitor for Cryptosporidium on the same schedule as filtered
systems of the same size. Because EPA was not able to identify
indicator criteria, such as E. coli, that can discriminate among
systems above and below a mean Cryptosporidium concentration of 0.01
oocysts/L, EPA is proposing that all unfiltered systems monitor for
Cryptosporidium.
Consistent with requirements for filtered systems, unfiltered
systems are required to analyze at least 24 samples of at least 10 L
over the two year monitoring period (one year for small systems).
However, if an unfiltered system collected and analyzed only 24 samples
of 10 L then a total count of 3 oocysts among all samples would result
in a source water concentration exceeding 0.01 oocysts/L. To avoid a
relatively small number of counts determining an additional treatment
implication, unfiltered systems may consider conducting more frequent
sampling or analyzing larger sample volumes (e.g., 50 L). Since the
water sources of unfiltered systems tend to have very low turbidity
(compared to average sources in filtered systems), it is typically more
feasible to analyze larger sample volumes in unfiltered systems.
Filters have been approved for Cryptosporidium analysis of 50 L
samples. Note that analysis of larger sample volumes would not reduce
the required sampling frequency.
3. Request for Comment
EPA solicits comment on the proposed monitoring and treatment
technique requirements for unfiltered systems. Specifically, the Agency
seeks comment on the following issues:
Use of Two Disinfectants
EPA requests comment on the proposed requirement for unfiltered
systems to use two disinfectants and for each disinfectant to meet by
itself the inactivation requirement for at least one regulated
pathogen. The requirement for unfiltered systems to use two
disinfectants was recommended by the Advisory Committee because (1)
disinfectants vary in their efficacy against different pathogens, so
that the use of multiple disinfectants can provide more effective
protection against a broad spectrum of pathogens, and (2) multiple
disinfectants provide multiple barriers of protection, which can be
more reliable than a single disinfectant.
An alternate approach would be to allow systems to meet the
inactivation requirements using any combination of one or more
disinfectants that achieved the required inactivation level for all
pathogens. This would give systems greater flexibility and could spur
the development of new disinfection techniques that would be applicable
to a wide range of pathogens. However, this approach might be less
protective against unregulated pathogens. A related question is whether
the proposed requirements for use of two disinfectants establish an
adequate level of multiple barriers in the treatment provided by
unfiltered systems.
Treatment Requirements for Unfiltered Systems With Higher
Cryptosporidium Levels
Under the proposed LT2ESWTR, a filtered system that measures a mean
source water Cryptosporidium level of 0.075 oocysts/L or higher is
required to provide a total of 4 log or more reduction of
Cryptosporidium. However, if an unfiltered system, meeting the criteria
for avoiding filtration were to measure Cryptosporidium at this level,
it would be required to provide only 3 log treatment. Available
occurrence data indicate that very few, if any, unfiltered systems will
measure mean source water Cryptosporidium concentrations above 0.075
oocysts/L. However, EPA requests comment on whether or how this
possibility should be addressed.

C. Options for Systems To Meet Cryptosporidium Treatment Requirements

1. Microbial Toolbox Overview
The LT2ESWTR proposal contains a list of treatment processes and
management practices for water systems to use in meeting additional
Cryptosporidium treatment requirements under the LT2ESWTR. This list,
termed the microbial toolbox, was recommended by the Stage 2 M-DBP
Advisory Committee in the Agreement in Principle. Components of the
microbial toolbox include watershed control programs, alternative
sources, pretreatment processes, additional filtration barriers,
inactivation technologies, and enhanced plant performance. The intent
of the microbial toolbox is to provide water systems with broad
flexibility in selecting cost-effective LT2ESWTR compliance strategies.
Moreover, the toolbox allows systems that currently provide additional
pathogen barriers or that can demonstrate enhanced performance to
receive additional Cryptosporidium treatment credit.
A key feature of the microbial toolbox is that many of the
components carry presumptive credits towards Cryptosporidium treatment
requirements. Plants will receive these credits for toolbox components
by demonstrating compliance with required design and implementation
criteria, as described in the sections that follow. Treatment credit
greater than the presumptive credit may be awarded for a toolbox
component based on a site-specific or technology-specific demonstration
of performance, as described in section IV.C.17.
While the Advisory Committee made recommendations for the degree of
presumptive treatment credit to be granted to different toolbox
components, the Committee did not specify the design and implementation
conditions under which the credit should be awarded. EPA has identified
and is proposing such conditions in today's notice, based on an
assessment of available data. For certain toolbox components, such as
raw water storage and roughing filters, the Agency concluded that
available data do not support the credit recommended by the Advisory
Committee. Consequently, EPA is not proposing a presumptive credit for
these options.
For each microbial toolbox component, EPA is requesting comment on:
(1) Whether available data support the proposed presumptive credits,
including the design and implementation conditions under which

[[Page 47682]]

the credit would be awarded, (2) whether available data are consistent
with the decision not to award presumptive credit for roughing filters
and raw water off-stream storage, and (3) whether additional data are
available on treatment effectiveness of toolbox components for reducing
Cryptosporidium levels. EPA will consider modifying today's proposal
for microbial toolbox components based on new information that may be
provided.
EPA particularly solicits comment on the performance of alternative
filtration technologies that are currently being used, as well as ones
that systems are considering for use in the future, specifically
including bag filters, cartridge filters, and bank filtration, in
removing Cryptosporidium. The Agency requests both laboratory and field
data that will support a determination of the appropriate level of
Cryptosporidium removal credit to award to these technologies. In
addition, the Agency requests information on the applicability of these
technologies to different source water types and treatment scenarios.
Data submitted in response to this request for comment should include,
where available, associated quality assurance and cost information.
This preamble discusses bank filtration in section IV.C.6 and bag and
cartridge filters in section IV.C.12.
Table IV-7 summarizes presumptive credits and associated design and
implementation criteria for microbial toolbox components. Each
component is then described in more detail in the sections that follow.
EPA is also developing guidance to assist systems with implementing
toolbox components. Pertinent guidance documents include: UV
Disinfection Guidance Manual (USEPA 2003d), Membrane Filtration
Guidance Manual (USEPA 2003e), and Toolbox Guidance Manual (USEPA
2003f). Each is available in draft form in the docket for today's
proposal (http://www.epa.gov/edocket/).

Table IV-7.--Microbial Toolbox: Proposed Options, Log Credits, and
Design/Implementation Criteria \1\
------------------------------------------------------------------------
Proposed Cryptosporidium log credit
Toolbox option with design and implementation
criteria\1\
------------------------------------------------------------------------
Watershed control program......... 0.5 log credit for State-approved
program comprising EPA specified
elements. Does not apply to
unfiltered systems.
Alternative source/Intake No presumptive credit. Systems may
management. conduct simultaneous monitoring for
LT2ESWTR bin classification at
alternative intake locations or
under alternative intake management
strategies.
Off-stream raw water storage...... No presumptive credit. Systems using
off-stream storage must conduct
LT2ESWTR sampling after raw water
reservoir to determine bin
classification.
Pre-sedimentation basin with 0.5 log credit with continuous
coagulation. operation and coagulant addition;
basins must achieve 0.5 log
turbidity reduction based on the
monthly mean of daily measurements
in 11 of the 12 previous months;
all flow must pass through basins.
Systems using existing pre-sed
basins must sample after basins to
determine bin classification and
are not eligible for presumptive
credit.
Lime softening.................... 0.5 log additional credit for two-
stage softening (single-stage
softening is credited as equivalent
to conventional treatment).
Coagulant must be present in both
stages--includes metal salts,
polymers, lime, or magnesium
precipitation. Both stages must
treat 100% of flow.
Bank filtration (as pretreatment). 0.5 log credit for 25 ft. setback;
1.0 log credit for 50 ft. setback;
aquifer must be unconsolidated sand
containing at least 10% fines;
average turbidity in wells must be
< 1 NTU. Systems using existing
wells followed by filtration must
monitor well effluent to determine
bin classification and are not
eligible for presumptive credit.
Combined filter performance....... 0.5 log credit for combined filter
effluent turbidity <= 0.15 NTU in
95% of samples each month.
Roughing filters.................. No presumptive credit proposed.
Slow sand filters................. 2.5 log credit as a secondary
filtration step; 3.0 log credit as
a primary filtration process. No
prior chlorination.
Second stage filtration........... 0.5 log credit for second separate
filtration stage; treatment train
must include coagulation prior to
first filter. No presumptive credit
for roughing filters.
Membranes......................... Log credit equivalent to removal
efficiency demonstrated in
challenge test for device if
supported by direct integrity
testing.
Bag filters....................... 1 log credit with demonstration of
at least 2 log removal efficiency
in challenge test.
Cartridge filters................. 2 log credit with demonstration of
at least 3 log removal efficiency
in challenge test.
Chlorine dioxide.................. Log credit based on demonstration of
log inactivation using CT table.
Ozone............................. Log credit based on demonstration of
log inactivation using CT table.
UV................................ Log credit based on demonstration of
inactivation with UV dose table;
reactor testing required to
establish validated operating
conditions.
Individual filter performance..... 1.0 log credit for demonstration of
filtered water turbidity < 0.1 NTU
in 95 percent of daily max values
from individual filters (excluding
15 min period following backwashes)
and no individual filter 0.3 NTU in two consecutive
measurements taken 15 minutes
apart.
Demonstration of performance...... Credit awarded to unit process or
treatment train based on
demonstration to the State, through
use of a State-approved protocol.
------------------------------------------------------------------------
\1\ Table provides summary information only; refer to following preamble
and regulatory language for detailed requirements.

2. Watershed Control Program
a. What is EPA proposing today? EPA is proposing a 0.5 log credit
towards Cryptosporidium treatment requirements under the LT2ESWTR for
filtered systems that develop a State-approved watershed control
program designed to reduce the level of Cryptosporidium. The watershed
control program credit can be added to the credit awarded for any other
toolbox component. However, this credit is not available to unfiltered
systems, as they are currently required under 40 CFR 141.171 to
maintain a watershed control

[[Page 47683]]

program that minimizes the potential for contamination by
Cryptosporidium as a criterion for avoiding filtration.
There are many potential sources of Cryptosporidium in watersheds,
including sewage discharges and non-point sources associated with
animal feces. The feasibility, effectiveness, and sustainability of
control measures to reduce Cryptosporidium contamination of water
sources will be site-specific. Consequently, the proposed watershed
control program credit centers on systems working with stakeholders in
the watershed to develop a site-specific program, and State review and
approval are required. In the Toolbox Guidance Manual (USEPA 2003f),
available in draft in the docket for today's proposal, EPA provides
information on management practices that systems may consider in
developing their watershed control programs.
Initial State approval of a system's watershed control program will
be based on State review of the system's proposed watershed control
plan and supporting documentation. The initial approval can be valid
until the system completes the second round of Cryptosporidium
monitoring described in section IV.A (systems begin a second round of
monitoring six years after the initial bin assignment). During this
period, the system is responsible for implementing the approved plan
and complying with other general requirements, such as an annual
watershed survey and program status report. These requirements are
further described later in this section.
The period during which State approval of a watershed control
program is in effect is referred to as the approval period. Systems
that want to continue their eligibility to receive the 0.5 log
Cryptosporidium treatment credit must reapply for State approval of the
program for each subsequent approval period. In general, the re-
approval will be based on the State's review of the system's
reapplication package, as well as the annual status reports and
watershed surveys. Subsequent approval(s) by the State of the watershed
control program typically will be for a time equivalent to the first
approval period, but States have the discretion to renew approval for a
longer or shorter time period.
Requirements for Initial State Approval of Watershed Control Programs
Systems that intend to pursue a 0.5 log Cryptosporidium treatment
credit for a watershed control program are required to notify the State
within one year following initial bin assignment that the system
proposes to develop a watershed control plan and submit it for State
approval.
The application to the State for initial program approval must
include the following minimum elements:
[sbull] An analysis of the vulnerability of each source to
Cryptosporidium. The vulnerability analysis must address the watershed
upstream of the drinking water intake, including: A characterization of
the watershed hydrology, identification of an ``area of influence''
(the area to be considered in future watershed surveys) outside of
which there is no significant probability of Cryptosporidium or fecal
contamination affecting the drinking water intake, identification of
both potential and actual sources of Cryptosporidium contamination, the
relative impact of the sources of Cryptosporidium contamination on the
system's source water quality, and an estimate of the seasonal
variability of such contamination.
[sbull] An analysis of control measures that could address the
sources of Cryptosporidium contamination identified during the
vulnerability analysis. The analysis of control measures must address
their relative effectiveness in reducing Cryptosporidium loading to the
source water and their sustainability.
[sbull] A plan that specifies goals and defines and prioritizes
specific actions to reduce source water Cryptosporidium levels. The
plan must explain how actions are expected to contribute to specified
goals, identify partners and their role(s), present resource
requirements and commitments including personnel, and include a
schedule for plan implementation.
The proposed watershed control plan and a request for program
approval and 0.5 log Cryptosporidium treatment credit must be submitted
by the system to the State no later than 24 months following initial
bin assignment.
The State will review the system's initial proposed watershed
control plan and either approve, reject, or ``conditionally approve''
the plan. If the plan is approved, or if the system agrees to
implementing the State's conditions for approval, the system will be
awarded 0.5 log credit towards LT2ESWTR Cryptosporidium treatment
requirements. A final decision on approval must be made no later than
three years following the system's initial bin assignment.
The initial State approval of the system's watershed control
program can be valid until the system completes the required second
round of Cryptosporidium monitoring. The system is responsible for
taking the required steps, described as follows, to maintain State
program approval and the 0.5 log credit during the approval period.
Requirements for Maintaining State Approval of Watershed Control
Programs
Systems that have obtained State approval of their watershed
control program are required to meet the following ongoing requirements
within each approval period to continue their eligibility for the 0.5
log Cryptosporidium treatment credit:
[sbull] Submit an annual watershed control program status report to
the State during each year of the approval period.
[sbull] Conduct an annual State-approved watershed survey and
submit the survey report to the State.
[sbull] Submit to the State an application for review and re-
approval of the watershed control program and for a continuation of the
0.5 log treatment credit for a subsequent approval period.
The annual watershed control program status report must describe
the system's implementation of the approved plan and assess the
adequacy of the plan to meet its goals. It must explain how the system
is addressing any shortcomings in plan implementation, including those
previously identified by the State or as the result of the watershed
survey. If it becomes necessary during implementation to make
substantial changes in its approved watershed control program, the
system must notify the State and provide a rationale prior to making
any such changes . If any change is likely to reduce the level of
source water protection, the system must also include the actions it
will take to mitigate the effects in its notification.
The watershed survey must be conducted according to State
guidelines and by persons approved by the State to conduct watershed
surveys. The survey must encompass the area of the watershed that was
identified in the State-approved watershed control plan as the area of
influence and, as a minimum, assess the priority activities identified
in the plan and identify any significant new sources of
Cryptosporidium.
The application to the State for review and re-approval of the
system's watershed control program must be provided to the State at
least six months before the current approval period expires or by a
date previously determined by the State. The request must include a
summary of activities and issues identified during the previous
approval period and a revised

[[Page 47684]]

plan that addresses activities for the next approval period, including
any new actual or potential sources of Cryptosporidium contamination
and details of any proposed or expected changes from the existing
State-approved program. The plan must address goals, prioritize
specific actions to reduce source water Cryptosporidium, explain how
actions are expected to contribute to achieving goals, identify
partners and their role(s), resource requirements and commitments, and
the schedule for plan implementation.
The annual program status reports, watershed control plan and
annual watershed sanitary surveys must be made available to the public
upon request. These documents must be in a plain language format and
include criteria by which to evaluate the success of the program in
achieving plan goals. If approved by the State, the system may withhold
portions of the annual status report, watershed control plan, and
watershed sanitary survey based on security considerations.
b. How was this proposal developed? The M-DBP Advisory Committee
recommended that systems be awarded 0.5 log Cryptosporidium treatment
credit for implementing a watershed control program. This
recommendation was based on the Committee's recognition that some
systems will be able to reduce the level of Cryptosporidium in their
source water by implementing a well-designed and focused watershed
control program. Moreover, the control measures used in the watershed
to reduce levels of Cryptosporidium are likely to reduce concentrations
of other pathogens as well.
EPA concurs that well designed watershed control programs that
focus on reducing levels of Cryptosporidium contamination of water
sources should be encouraged, and that implementation of such programs
will likely reduce overall microbial risk. A broad reduction in
microbial risk will occur through the application of control measures
and best management practices that are effective in reducing fecal
contamination in the watershed. In addition, plant management practices
may be enhanced by the knowledge systems acquire regarding the
watershed and factors that affect microbial risk, such as sources,
fate, and transport of pathogens.
Given the highly site-specific nature of a watershed control
program, including the feasibility and effectiveness of different
control measures, EPA believes that systems should demonstrate their
eligibility for 0.5 log Cryptosporidium treatment credit by developing
targeted programs that account for site-specific factors. As part of
developing a watershed control program, systems will be required to
assess a number of these factors, including watershed hydrology,
sources of Cryptosporidium in the watershed, human impacts, and fate
and transport of Cryptosporidium. Furthermore, EPA believes that the
State is well positioned to judge whether a system's watershed control
program is likely to achieve a substantial reduction of Cryptosporidium
in source water. Consequently, EPA is proposing that approval of
watershed control programs and allowance for an associated 0.5 log
treatment credit be made by the State on a system specific basis.
A watershed control program could include measures such as (1) the
elimination, reduction, or treatment of wastewater or storm water
discharges, (2) treatment of Cryptosporidium contamination at the sites
of waste generation or storage, (3) prevention of Cryptosporidium
migration from sources, or (4) any other measures that are effective,
sustainable, and likely to reduce Cryptosporidium contamination of
source water. EPA recognizes that many public water systems do not
directly control the watersheds of their sources of supply. EPA expects
that systems will need to develop and maintain partnerships with
landowners within watersheds, as well as with State governments and
regional agencies that have authority over activities in the watershed
that may contribute Cryptosporidium to the water supply. Stakeholders
that have some level of control over activities that could contribute
to Cryptosporidium contamination include municipal government and
private operators of wastewater treatment plants, livestock farmers and
persons who spread manure, individuals with failing septic systems,
logging operations, and other government and commercial organizations.
EPA has initiated a number of programs that address watershed
management and source water protection. In 2002, EPA launched the
Watershed Initiative (67 FR 36172, May 23, 2002) (USEPA 2002b), which
will provide grants to support innovative watershed based approaches to
preventing, reducing, and eliminating water pollution. In addition, EPA
has recently promulgated new regulations for Concentrated Animal
Feeding Operations (CAFOs), which through the NPDES permit process will
limit discharges that contribute microbial pathogens to watersheds.
SDWA section 1453 requires States to carry out a source water
quality assessment program for the protection and benefit of public
water systems. EPA issued program guidance in August of 1997, and
expects that most States will complete their source water assessments
of surface water systems by the end of 2003. These assessments will
establish a foundation for watershed vulnerability analyses by
providing the preliminary analyses of watershed hydrology, a starting
point for defining the area of influence, and an inventory and
hierarchy of actual and potential contamination sources. In some cases,
these portions of the source water assessment may fully satisfy those
analytical needs.
As noted earlier, EPA has published and is continuing to develop
guidance material that addresses contamination by Cryptosporidium and
other pathogens from both non-point sources (e.g., agricultural and
urban runoff, septic tanks) and point sources (e.g., sewer overflows,
POTWs, CAFOs). The Toolbox Guidance Manual, available in draft with
today's proposal, includes a list of programmatic resources and
guidance available to assist systems in building partnerships and
implementing watershed protection activities. In addition, this
guidance manual incorporates available information on the effectiveness
of different control measures to reduce Cryptosporidium levels and
provides case studies of watershed control programs. This guidance is
intended to assist water systems in developing their watershed control
programs and States in their assessment and approval of these programs.
In addition to guidance documents, demonstration projects, and
technical resources, EPA provides funding for watershed and source
water protection through the Drinking Water State Revolving Fund
(DWSRF) and Clean Water State Revolving Fund (CWSRF). Under the DWSRF
program, States may provide funding directly to public water systems
for source water protection, including watershed management and
pathogen source reduction plans. CWSRF funds have been used to develop
and implement agricultural best management practices for reducing
pathogen loading to receiving waters and to fund directly, or provide
incentives for, the replacement of failing septic systems. EPA
encourages the use of CWSRF for source protection and has developed
guidelines for the award of funds to address non-point sources of
pollution (CWA section 319 Non Point Source Pollution Program).
Further, the Agency is promoting the broader use of

[[Page 47685]]

SRF funds to implement measures to prevent and control non-point source
pollution. Detailed sanitary surveys, with a specific analysis of
sources of Cryptosporidium in the watershed, will facilitate the
process of targeting funding available under SRF programs to eliminate
or mitigate these sources.
c. Request for comment. EPA requests comment on the proposed
watershed control program credit and associated program components.
[sbull] Should the State be allowed to reduce the frequency of the
annual watershed survey requirement for certain systems if systems
engage in alternative activities like public outreach?
[sbull] The effectiveness of a watershed control program may be
difficult to assess because of uncertainty in the efficacy of control
measures under site-specific conditions. In order to provide
constructive guidance, EPA welcomes reports on scientific case studies
and research that evaluated methods for reducing Cryptosporidium
contamination of source waters.
[sbull] Are there confidential business information (CBI) concerns
associated with making information on the watershed control program
available to the public? If so, what are these concerns and how should
they be addressed?
[sbull] How should the ``area of influence'' (the area to be
considered in future watershed surveys) be delineated, considering the
persistence of Cryptosporidium?
3. Alternative Source
a. What is EPA proposing today? Plant intake refers to the works or
structures at the head of a conduit through which water is diverted
from a source (e.g., river or lake) into the treatment plant. Plants
may be able to reduce influent Cryptosporidium levels by changing the
intake placement (either within the same source or to an alternate
source) or managing the timing or level of withdrawal.
Because the effect of changing the location or operation of a plant
intake on influent Cryptosporidium levels will be site specific, EPA is
not proposing any presumptive credit for this option. Rather, if a
system is concerned that Cryptosporidium levels associated with the
current plant intake location and/or operation will result in a bin
assignment requiring additional treatment under the LT2ESWTR, the
system may conduct concurrent Cryptosporidium monitoring reflecting a
different intake location or different intake management strategy. The
State will then make a determination as to whether the plant may be
classified in an LT2ESWTR bin using the alternative intake location or
management monitoring results.
Thus, systems that intend to be classified in an LT2ESWTR bin based
on a different intake location or management strategy must conduct
concurrent Cryptosporidium monitoring. The system is still required to
monitor its current plant intake in addition to any alternative intake
location/management monitoring, and must submit the results of all
monitoring to the State. In addition, the system must provide the State
with supporting information documenting the conditions under which the
alternative intake location/management samples were collected. The
concurrent monitoring must conform to the sample frequency, sample
volume, analytical method, and other requirements that apply to the
system for Cryptosporidium monitoring as stated in Section IV.A.1.
If a plant's LT2ESWTR bin classification is based on monitoring
results reflecting a different intake location or management strategy,
the system must relocate the intake or implement the intake management
strategy within the compliance time frame for the LT2ESWTR, as
specified in section IV.F.
b. How was this proposal developed? In the Stage 2 M-DBP Agreement
in Principle, the Advisory Committee identified several actions related
to the intake which potentially could reduce the concentration of
Cryptosporidium entering a treatment plant. These actions were included
in the microbial toolbox under the heading Alternative Source, and
include: (1) Intake relocation, (2) change to alternative source of
supply, (3) management of intake to reduce capture of oocysts in source
water, (4) managing timing of withdrawal, and (5) managing level of
withdrawal in water column.
It is difficult to predict in advance the efficacy of any of these
activities in reducing levels of Cryptosporidium entering the treatment
plant. However, if a system relocates the plant intake or implements a
different intake management strategy, it is appropriate for the plant
to be assigned to an LT2ESWTR bin using monitoring results reflecting
the new intake strategy.
EPA believes that the requirements specified for monitoring to
determine bin placement are necessary to characterize a plant's mean
source water Cryptosporidium level. Consequently, any concurrent
monitoring carried out to characterize a different intake location or
management strategy should be equivalent. For this reason, the sampling
and analysis requirements which apply to the current intake monitoring
also apply to any concurrent monitoring used to characterize a new
intake location or management strategy.
EPA also recognizes that if plant's bin assignment is based on a
new intake operation strategy then it is important for the plant to
continue to use this new strategy in routine operation. Therefore, EPA
is proposing that the system document the new intake operation strategy
when submitting additional monitoring results to the State and that the
State approve that new strategy.
c. Request for comment. EPA requests comment on the following
issues:
[sbull] What are intake management strategies by which systems
could reduce levels of Cryptosporidium in the plant influent?
[sbull] Can representative Cryptosporidium monitoring to
demonstrate a reduction in oocyst levels be accomplished prior to
implementation of a new intake strategy (e.g., monitoring a new source
prior to constructing a new intake structure)?
[sbull] How should this option be applied to plants that use
multiple sources which enter a plant through a common conduit, or which
use separate sources which enter the plant at different points?
4. Off-Stream Raw Water Storage
a. What is EPA proposing today? Off-stream raw water storage
reservoirs are basins located between a water source (typically a
river) and the coagulation and filtration processes in a treatment
plant. EPA is not proposing presumptive treatment credit for
Cryptosporidium removal through off-stream raw water storage. Systems
using off-stream raw water storage must conduct Cryptosporidium
monitoring after the reservoir for the purpose of determining LT2ESWTR
bin placement. This will allow reductions in Cryptosporidium levels
that occur through settling during off-stream storage to be reflected
in the monitoring results and consequent LT2ESWTR bin assignment.
The use of off-stream raw water storage reservoirs during LT2ESWTR
monitoring must be consistent with routine plant operation and must be
recorded by the system. Guidance on monitoring locations is provided in
Public Water System Guidance Manual for Source Water Monitoring under
the LT2ESWTR (USEPA 2003g), which is available in draft in the docket
for today's proposal.
b. How was this proposal developed? The Stage 2 M-DBP Agreement in
Principle recommends a 0.5 log credit for off-stream raw water storage

[[Page 47686]]

reservoirs with detention times on the order of days and 1.0 log credit
for reservoirs with detention times on the order of weeks. After a
review of the available literature, EPA is unable to determine criteria
that provide reasonable assurance of achieving a 0.5 or 1 log removal
of oocysts. Consequently, EPA is not proposing a presumptive treatment
credit for this process.
This proposal for off-stream raw water storage represents a change
from the November 2001 pre-proposal draft of the LT2ESWTR (USEPA
2001g), which described 0.5 log and 1 log presumptive credits for
reservoirs with hydraulic detention times of 21 and 60 days,
respectively. These criteria were based on a preliminary assessment of
reported studies, described later in this section, that evaluated
Cryptosporidium and Giardia removal in raw water storage reservoirs.
Subsequent to the November 2001 pre-proposal draft, the Science
Advisory Board (SAB) reviewed the data that EPA had acquired to support
Cryptosporidium treatment credits for off-stream raw water storage (see
section VII.K). In written comments from a December 2001 meeting of the
SAB Drinking Water Committee, the panel concluded that the available
data were not adequate to demonstrate the treatment credits for off-
stream raw water storage described in the pre-proposal draft, and
recommended that no presumptive credits be given for this toolbox
option. The panel did agree, though, that a utility should be able to
take advantage of off-stream raw water storage by sampling after the
reservoir for appropriate bin placement. EPA concurs with this finding
by the SAB and today's proposal is consistent with their
recommendation.
Off-stream raw water storage can improve the microbial quality of
water in a number of ways. These include (1) reduced microbial and
particulate loading to the plant due to settling in the reservoir, (2)
reduced viability of pathogens due to die-off, and (3) dampening of
water quality and hydraulic spikes. EPA has evaluated a number of
studies that investigated the removal of Cryptosporidium and other
microorganisms and particles in raw water storage basins. These studies
are summarized in the following paragraphs, and selected results are
presented in Table IV-8.

Table IV-8.--Studies of Cryptosporidium and Giardia Removal From Off-Stream Raw Water Storage
----------------------------------------------------------------------------------------------------------------
Researcher Reservoir Residence time Log reductions
----------------------------------------------------------------------------------------------------------------
Ketelaars et al. 1995........... Biesbosch reservoir 24 weeks (average)................... Cryptosporidium-
system: man-made 1.4 Giardia-2.3.
pumped storage
(Netherlands).
Van Breeman et al. 1998......... Biesbosch reservoir 24 weeks (average)................... Cryptosporidium-
system: man-made 2.0 Giardia-2.6.
pumped storage
(Netherlands).
PWN (Netherlands).. 10 weeks (average)................... Cryptosporidium-
1.3 Giardia-0.8.
Bertolucci et al. 1998.......... Abandoned gravel 18 days (theoretical)................ Cryptosporidium-
quarry used for 1.0 Giardia-0.8.
storage (Italy).
Ongerth, 1989................... Three impoundments 40, 100 and 200 days (respectively).. No Giardia removal
on rivers with observed.
limited public
access (Seattle,
WA).
----------------------------------------------------------------------------------------------------------------

Ketelaars et al. (1995) evaluated Cryptosporidium and Giardia
removal across a series of three man-made pumped reservoirs, named the
Biesbosch reservoirs, with reported hydraulic retention times of 11, 9,
and 4 weeks (combined retention time of 24 weeks). To prevent algal
growth and hypolimnetic deoxygenation, the reservoirs were destratified
by air-injection. Based on weekly sampling over one year, mean influent
and effluent concentrations of Cryptosporidium were 0.10 and 0.004
oocysts/100 L, respectively, indicating an average removal across the
three reservoirs of 1.4 log. Mean removal of Giardia was 2.3 log.
Van Breemen et al. (1998) continued the efforts of Ketelaars et al.
(1995) in evaluating pathogen removal across the Biesbosch reservoir
system. Using a more sensitive analytical method, Van Breeman et al.
measured mean Cryptosporidium levels of 6.3 and 0.064 oocysts/100 L at
the inlet and outlet, respectively, indicating an average removal of
2.0 log. For Giardia, the average reduction was 2.6 log. In addition,
Van Breeman et al. (1998) evaluated removal of Cryptosporidium,
Giardia, and other microorganisms in a reservoir designated PWN, which
had a hydraulic retention time of 10 weeks. Passage through this
storage reservoir was reported to reduce the mean concentration of
Cryptosporidium by 1.3 log and of Giardia by 0.8 log.
Bertolucci et al. (1998) investigated removal of Cryptosporidium,
Giardia, and nematodes in a reservoir derived from an abandoned gravel
quarry with a detention time reported as around 18 days. Over a 2 year
period, average influent and effluent concentrations of Cryptosporidium
were 70 and 7 oocysts/100 L, respectively, demonstrating a mean
reduction of 1 log. Average Giardia levels decreased from 137 cysts/
100L in the inlet to 46 cysts/100L at the outlet, resulting in a mean
0.5 log removal.
Ongerth (1989) studied concentrations of Giardia cysts in the Tolt,
Cedar, and Green rivers, which drain the western slope of the Cascade
Mountains in Washington. The watersheds of each river are controlled by
municipal water departments for public water supply, and public access
is limited. The Cedar, Green, and Tolt rivers each have impoundments
with reported residence times of 100, 30-50, and 200 days,
respectively, in the reach studied. Ongerth found no statistically
significant difference in cyst concentrations above and below any of
the reservoirs. Median cyst concentrations above and below the Cedar,
Green, and Tolt reservoirs were reported as 0.12 and 0.22, 0.27 and
0.32, and 0.16 and 0.21 cysts/L, respectively. It is unclear why no
decrease in cyst levels was observed. It is possible that contamination
of the water in the impoundments by Giardia from animal sources, either
directly or through run-off, may have occurred.
EPA has also considered results from studies which evaluated the
rate at which Cryptosporidium oocysts lose viability and infectivity
over time. Two studies are summarized next, with selected results
presented in Table IV-9.

[[Page 47687]]

Table IV-9.--Studies of Cryptosporidium Die-Off During Raw Water Storage
------------------------------------------------------------------------
Researcher Type of experiment Log reduction
------------------------------------------------------------------------
Medema et al. 1997.......... River water was 0.5 log reduction
inoculated with over 50 days at 5
Cryptosporidium and [deg]C; 0.5 log
bacteria and reduction over 20-
incubated. 80 days at 15
[deg]C.
Sattar et al. 1999.......... Synthetic hard water In vitro conditions
and natural water showed 0.7 to 2.0
from several rivers log reduction over
inoculated with 30 days at 20
Giardia and [deg]C. Little
Cryptosporidium. reduction at 4
[deg]C. In situ
conditions showed
0.4 to 1.5 log
reduction at 21
days.
------------------------------------------------------------------------

Medema et al. (1997) conducted bench scale studies of the influence
of temperature and the presence of biological activity on the die-off
rate of Cryptosporidium oocysts. Die-off rates were determined at
5[deg]C and 15[deg]C, and in both natural and sterilized (autoclaved)
river water. Both excystation and vital dye staining were used to
determine oocyst viability. At 5[deg]C, the die-off rate under all
conditions was 0.010 log10/day, assuming first-order
kinetics. This translates to 0.5 log reduction at 50 days. At 15[deg]C,
the die-off rate in natural river water approximately doubled to 0.024
log10/day (excystation) and 0.018 log10/day (dye
staining). However, in autoclaved water at 15[deg]C, the die-off rate
was only 0.006 log10/day (excystation) and 0.011
log10/day (dye staining). These results suggest that oocyst
die-off is more rapid at higher temperatures in natural water, and this
behavior may be caused by increased biological or biochemical activity.
Sattar et al. (1999) evaluated factors impacting Cryptosporidium
and Giardia survival. Microtubes containing untreated water from the
Grand and St. Lawrence rivers (Ontario) were inoculated with purified
oocysts and cysts. Samples were incubated at temperatures ranging from
4[deg]C to 30[deg]C, viability of oocysts and cysts was measured by
excystation. At 20[deg]C and 30[deg]C, reductions in viable
Cryptosporidium oocysts ranged from approximately 0.6 to 2.0 log after
30 days. However, relatively little inactivation took place when
oocysts were incubated at 4[deg]C (as low as 0.2 log at 100 days).
To evaluate oocyst survival under dynamic environmental conditions,
Sattar et al. seeded dialysis cassettes with Cryptosporidium oocysts
and placed them in overflow tanks receiving water from different rivers
in Canada and the United States. Reductions in the concentration of
viable oocysts ranged from approximately 0.4 to 1.5 log after 21 days.
Survival of oocysts was enhanced by pre-filtering the water, suggesting
that microbial antagonism was involved in the natural inactivation of
the parasites.
Overall these studies indicate that off-stream storage of raw water
has the potential to effect significant reductions in the concentration
of viable Cryptosporidium oocysts, both through sedimentation and
degradation of oocysts (i.e., die-off). However, these data also
illustrate the challenge in reliably estimating the amount of removal
that will occur in any particular storage reservoir. Removal and die-
off rates reported in these studies varied widely, and were observed to
be influenced by factors like temperature, contamination, hydraulic
short circuiting, and biological activity (Van Breeman et al. 1998,
Medema et al. 1997, Sattar et al. 1999). Because of this variability
and the relatively small amount of available data, it is difficult to
extrapolate from these studies to develop nationally applicable
criteria for awarding removal credits to raw water storage.
c. Request for comment. EPA requests comment on the finding that
the available data are not adequate to support a presumptive
Cryptosporidium treatment credit for off-stream raw water storage, and
that systems using off-stream storage should conduct LT2ESWTR
monitoring at the reservoir outlet. This monitoring approach would
account for reductions in oocyst concentrations due to settling, but
would not provide credit for die-off, since non-viable oocysts could
still be counted during monitoring. In addition, EPA would also
appreciate comment on the following specific issues:
[sbull] Is additional information available that either supports or
suggests modifications to this proposal concerning off-stream raw water
storage?
[sbull] How should a system address the concern that water in off-
stream raw water storage reservoirs may become contaminated through
processes like algal growth, run-off, roosting birds, and activities on
the watershed?
5. Pre-Sedimentation With Coagulant
a. What is EPA proposing today? Presedimentation is a preliminary
treatment process used to remove particulate material from the source
water before the water enters primary sedimentation and filtration
processes in a treatment plant. EPA is proposing to award a presumptive
0.5 log Cryptosporidium treatment credit for presedimentation that is
installed after LT2ESWTR monitoring and meets the following three
criteria:
(1) The presedimentation basin must be in continuous operation and
must treat all of the flow reaching the treatment plant.
(2) The system must continuously add a coagulant to the
presedimentation basin.
(3) The system must demonstrate on a monthly basis at least 0.5 log
reduction of influent turbidity through the presedimentation process in
at least 11 of the 12 previous consecutive months. This monthly
demonstration of turbidity reduction must be based on the arithmetic
mean of at least daily turbidity measurements in the presedimentation
basin influent and effluent, and must be calculated as follows:

Monthly mean turbidity log reduction = log10(monthly mean of
daily influent turbidity)-log10(monthly mean of daily
effluent turbidity).

If the presedimentation process has not been in operation for 12
months, the system must verify on a monthly basis at least 0.5 log
reduction of influent turbidity through the presedimentation process,
calculated as specified in this paragraph, for at least all but any one
of the months of operation.
Systems with presedimentation in place at the time they begin
LT2ESWTR Cryptosporidium monitoring are not eligible for the 0.5 log
presumptive credit and must sample after the basin when in use for the
purpose of determining their bin assignment. The use of
presedimentation during LT2ESWTR monitoring must be consistent with
routine plant operation and must be recorded by the system. Guidance on
monitoring is provided in Public Water System Guidance Manual for
Source Water Monitoring under the LT2ESWTR (USEPA 2003g), which is
available in draft in the docket for today's proposal.
b. How was this proposal developed? Presedimentation is used to
remove gravel, sand, and other gritty material

[[Page 47688]]

from the raw water and dampen particle loading to the rest of the
treatment plant. Presedimentation is similar to conventional
sedimentation, except that presedimentation may be operated at higher
loading rates and may not involve use of chemical coagulants. Also,
some systems operate the presedimentation process periodically and only
in response to periods of high particle loading.
Because presedimentation reduces particle concentrations, it is
expected to reduce Cryptosporidium levels. In addition, by dampening
variability in source water quality, presedimentation may improve the
performance of subsequent treatment processes. In general, the efficacy
of presedimentation in lowering particle levels is influenced by a
number of water quality and treatment parameters including surface
loading rate, temperature, particle concentration, coagulation, and
characteristics of the sedimentation basin.
The Stage 2-M-DBP Agreement in Principle recommends 0.5 log
presumptive Cryptosporidium treatment credit for presedimentation with
the use of coagulant. Today's proposal is consistent with this
recommendation. However, the proposed requirement for demonstrated
turbidity reduction as a condition for presedimentation credit
represents a change from the November 2001 pre-proposal draft of the
LT2ESWTR (USEPA 2001g). Rather than a requirement for turbidity
removal, the 2001 pre-proposal draft included criteria for maximum
overflow rate and minimum influent turbidity as conditions for the 0.5
log presedimentation credit.
The Science Advisory Board (SAB) reviewed the criteria and
supporting information for presedimentation credit in the November 2001
pre-proposal draft (see section VII.K). In written comments from a
December 2001 meeting of the SAB Drinking Water Committee, the panel
concluded that available data were minimal to support a 0.5 log
presumptive credit and recommended that no credit be given for
presedimentation. Additionally, the panel stated that performance
criteria other than overflow rate need to be included if credit is to
be given for presedimentation.
Due to this finding by the SAB, EPA further reviewed data on
removal of aerobic spores (as an indicator of Cryptosporidium removal)
and turbidity in full-scale presedimentation basins. As shown later in
this section, these data indicate that presedimentation basins
achieving a monthly mean reduction in turbidity of at least 0.5 log
have a high likelihood of reducing mean Cryptosporidium levels by 0.5
log or more. Consequently, EPA has determined that it is appropriate to
use turbidity reduction as a performance criterion for awarding
Cryptosporidium treatment credit to presedimentation basins. The Agency
believes this performance criterion addresses the concerns raised by
the SAB.
The Agency has concluded that it is appropriate to limit
eligibility for the 0.5 log presumptive Cryptosporidium treatment
credit to systems that install presedimentation after LT2ESWTR
monitoring. Systems with presedimentation in place prior to initiation
of LT2ESWTR Cryptosporidium monitoring may sample after the
presedimentation basin to determine their bin assignment. In this case,
the effect of presedimentation in reducing Cryptosporidium levels will
be reflected in the monitoring results and bin assignment. Systems that
monitor after presedimentation are not subject to the operational and
performance requirements associated with the 0.5 log credit. The SAB
agreed that a system should be able to sample after the
presedimentation treatment process for appropriate bin placement.
In considering criteria for awarding Cryptosporidium removal credit
to presedimentation, EPA has evaluated both published studies and data
submitted by water systems using presedimentation. There is relatively
little published data on the removal of Cryptosporidium by
presedimentation. Consequently, EPA has reviewed studies that
investigated Cryptosporidium removal by conventional sedimentation
basins. These studies are informative regarding potential levels of
performance, the influence of water quality parameters, and correlation
of Cryptosporidium removal with removal of potential surrogates.
However, removal efficiency in conventional sedimentation basins may be
greater than in presedimentation due to lower surface loading rates,
higher coagulant doses, and other factors. To supplement these studies,
EPA has evaluated data provided by utilities on removal of other types
of particles, primarily aerobic spores, in the presedimentation
processes of full scale plants. Data indicate that aerobic spores may
serve as a surrogate for Cryptosporidium removal by sedimentation
(Dugan et al. 2001).
i. Published studies of Cryptosporidium removal by conventional
sedimentation basins. Table IV-10 summarizes results from published
studies of Cryptosporidium removal by conventional sedimentation
basins.

Table IV-10.--Summary of Published Studies of Cryptosporidium Removal by Conventional Sedimentation Basins
----------------------------------------------------------------------------------------------------------------
Author(s) Plant/process type Cryptosporidium removal by sedimentation
----------------------------------------------------------------------------------------------------------------
Dugan et al. (2001).................. Pilot scale 0.6 to 1.6 log (average 1.3 log).
conventional.
States et al. (1997)................. Full scale conventional 0.41 log.
with primary and
secondary
sedimentation.
Edzwald and Kelly (1998)............. Bench scale 0.8 to 1.2 log.
sedimentation.
Payment and Franco (1993)............ Full scale conventional 3.8 log and 0.7 log.
(2 plants).
Kelly et al. (1995).................. Full scale conventional 0.8 log.
(two stage lime
softening).
Full scale conventional 0.5 log.
(two stage
sedimentation).
Patania et al. (1995)................ Pilot scale 2.0 log (median).
conventional (3
plants).
----------------------------------------------------------------------------------------------------------------

Dugan et al. (2001) evaluated the ability of conventional treatment
to control Cryptosporidium under different water quality and treatment
conditions on a small pilot scale plant that had been demonstrated to
provide equivalent performance to a larger plant. Under optimal
coagulation conditions, oocyst removal across the sedimentation basin
ranged from 0.6 to 1.6 log, averaging 1.3 log. Suboptimal coagulation
conditions (underdosed relative to jar test predictions) significantly
reduced plant performance with oocyst removal in the

[[Page 47689]]

sedimentation basin averaging 0.20 log. Removal of aerobic spores,
total particle counts, and turbidity all correlated well with removal
of Cryptosporidium by sedimentation.
States et al. (1997) monitored Cryptosporidium removal at the
Pittsburgh Drinking Water Treatment Plant (65-70 million gallons per
day (MGD)). The clarification process included ferric chloride
coagulation, flocculation, and settling in both a small primary basin
and a 120 MG secondary sedimentation basin. Geometric mean
Cryptosporidium levels in the raw and settled water were 31 and 12
oocysts/100 L, respectively, indicating a mean reduction of 0.41 log.
Edzwald and Kelly (1998) conducted a bench-scale study to determine
the optimal coagulation conditions with different coagulants for
removing Cryptosporidium oocysts from spiked raw waters. Under optimal
coagulation conditions, the authors observed oocysts reductions through
sedimentation ranging from 0.8 to 1.2 log.
Payment and Franco (1993) measured Cryptosporidium and other
microorganisms in raw, settled, and filtered water samples from
drinking water treatment plants in the Montreal area. The geometric
mean of raw and settled water Cryptosporidium levels in one plant were
742 and 0.12 oocysts/100 L, respectively, suggesting a mean removal of
3.8 log. In a second plant, mean removal by sedimentation was reported
as 0.7 log, with raw and settled water Cryptosporidium levels reported
as <2 and <0.2 oocysts/L, respectively.
Kelley et al. (1995) monitored Cryptosporidium levels in the raw,
settled, and filtered water of two water treatment plants (designated
site A and B). Both plants included two-stage sedimentation. At site A,
mean raw and settled water Cryptosporidium levels were 60 and 9.5
oocysts/100 L, respectively, suggesting a mean removal of 0.8 log by
sedimentation. At site B, mean raw and settled water Cryptosporidium
levels were 53 and 16 oocysts/100 L, respectively, for an average
removal by sedimentation of 0.5 log. Well water was intermittently
blended in the second stage of sedimentation at site B, which may have
reduced settled and filtered water pathogen levels.
Patania et al. (1995) evaluated removal of Cryptosporidium in four
pilot scale plants. Three of these were conventional and one used in-
line filtration (rapid mix followed by filtration). Cryptosporidium
removal was generally 1.4 to 1.8 log higher in the process trains with
sedimentation compared to in-line filtration. While the effectiveness
of sedimentation for organism removal varied widely under the
conditions tested, the median removal of Cryptosporidium by
sedimentation was approximately 2.0 log.
ii. Data supplied by utilities on the removal of spores by
presedimentation. Data on the removal of Cryptosporidium and spores
(Bacillus subtilis and total aerobic spores) during operation of full-
scale presedimentation basins were collected independently and reported
by three utilities: St. Louis, MO, Kansas City, MO, and Cincinnati, OH.
Cryptosporidium oocysts were not detected in raw water at these
locations at levels sufficient to calculate log removals of oocysts
directly. However, aerobic spores were present in the raw water of
these utilities at high enough concentrations to measure log removals
through presedimentation as a surrogate for Cryptosporidium removal. As
noted earlier, data from Dugan et al. (2001) demonstrate a correlation
between removal of aerobic spores and Cryptosporidium through
sedimentation under optimal coagulation conditions. A summary of the
spore removal data supplied by the these utilities is shown in Table
IV-11.

Table IV-11.--Mean Spore Removal for Full-scale Presedimentation Basins
Reported by Three Utilities
------------------------------------------------------------------------
Reporting utility Mean spore removal
------------------------------------------------------------------------
St. Louis Water Division.................. 1.1 log (B. subtilis).
Kansas City Water Services Department..... 0.8 log (B. subtilis) (with
coagulant).
0.46 log (B. subtilis)
(without coagulant).
Cincinnati Water Works.................... 0.6 log (total aerobic
spores).
------------------------------------------------------------------------

The St. Louis Water Division operates four presedimentation basins
at one facility. Coagulant addition prior to presedimentation includes
polymer and occasional dosages of ferric sulfate. Bacillus subtilis
spore samples were collected from June 1998 to September 2000. Reported
mean spore concentrations in the raw water and following
presedimentation were 108,326 and 8,132 cfu/100 mL, respectively,
showing an average removal of 1.1 log by presedimentation.
The Kansas City Water Services Department collected Bacillus
subtilis spore samples from January to November 2000 from locations
before and after one of the facility's six presedimentation basins.
Sludge generated by the primary clarifier of a softening process was
recycled to the head of the presedimentation basins during the entire
study period. In addition, coagulant (polymer and/or ferric sulfate)
was added prior to presedimentation when raw water turbidity was
higher. During periods when coagulant was added, mean spore levels
before and after presedimentation were 102,292 and 13,154 cfu/100 mL,
respectively, demonstrating a mean removal of 0.9 log. When no ferric
sulfate or polymer was used, mean presedimentation influent and
effluent spore levels were 13,296 and 4,609 cfu/100 mL, respectively,
for an average reduction of 0.46 log.
The Cincinnati Water Works operates a treatment plant using lamella
plate settlers for presedimentation. Lamella plate settlers are
inclined plates added to a sedimentation basin to significantly
increase the surface area available for particle settling. Coagulant
(alum and polymer) is added to the raw water prior to presedimentation.
Total aerobic spore samples were collected from January 1998 through
December 2000. The mean concentration of spores decreased from 20,494
cfu/100 mL in the raw water to 4,693 cfu/100 mL in the presedimentation
effluent, indicating a mean spore removal of 0.64 log.
In conclusion, literature studies clearly establish that
sedimentation basins are capable of achieving greater than 0.5 log
reduction in Cryptosporidium levels. Further, the data supplied by
utilities on reduction in aerobic spore counts across full scale
presedimentation basins demonstrate that presedimentation can achieve
mean reductions of greater than 0.5 log under routine operating
conditions and over an extended time period. Thus, these data suggest
that a 0.5 log presumptive credit for Cryptosporidium removal by
presedimentation is appropriate under certain conditions.
With respect to the conditions under which the 0.5 log presumptive
credit for presedimentation is appropriate, the data do not demonstrate
that this level of removal can be achieved consistently without a
coagulant. In addition, available data do not establish aerobic spores
as an effective indicator of Cryptosporidium removal in the absence of
a coagulant. Thus, supporting data are consistent with a requirement
that systems apply a coagulant to be eligible for the presumptive 0.5
log presedimentation credit. Moreover, such a requirement is consistent
with the Agreement in Principle, which recommends 0.5 log credit for
presedimentation basins with a coagulant.

[[Page 47690]]

EPA also has concluded that presedimentation basins need to be
operated continuously and treat 100% of the plant flow in order to
reasonably ensure that the process will reduce influent Cryptosporidium
levels by at least 0.5 log over the course of a full year. The Agency
recognizes that, depending on influent water quality, some systems may
determine it is more prudent to operate presedimentation basins
intermittently in response to fluctuating turbidity levels. By
proposing these conditions for the presumptive presedimentation credit,
EPA is not recommending against intermittent operation of
presedimentation basins. Rather, EPA is attempting to identify the
conditions under which a 0.5 log presumptive credit for
presedimentation is warranted.
In response to the SAB panel recommendation that performance
criteria other than overflow rate be included if credit is to be given
for presedimentation, EPA analyzed the relationship between removal of
spores and reduction in turbidity through presedimentation for the
three utilities that supplied these data. Results of this analysis are
summarized in Table IV-12, which shows the relationship between monthly
mean turbidity reduction and the percent of months when mean spore
removal was at least 0.5 log.

BILLING CODE 6560-50-P

[GRAPHIC] [TIFF OMITTED] TP11AU03.007

BILLING CODE 6560-50-C
Within the available data set, achieving a mean turbidity reduction
of at least 0.5 log appears to provide approximately a 90% assurance
that average spore removal will be 0.5 log or greater. The underlying
data are shown graphically in Figure IV-4. Based on this information,
EPA has concluded that it is appropriate to require 0.5 log turbidity
reduction, determined as a monthly mean of daily turbidity readings, as
an operating condition for the 0.5 log presumptive Cryptosporidium
treatment credit for presedimentation. Further, EPA is proposing that
systems must meet the 0.5 log turbidity reduction requirement in at
least 11 of the 12 previous months on an ongoing basis to remain
eligible for the presedimentation credit.

BILLING CODE 6560-50-P

[[Page 47691]]

[GRAPHIC] [TIFF OMITTED] TP11AU03.008

BILLING CODE 6560-50-C

c. Request for comment. EPA requests comment on the proposed
criteria for awarding credit to presedimentation. EPA would
particularly appreciate comment on the following issues:
[sbull] Whether the information cited in this proposal supports the
proposed credit for presedimentation and the operating conditions under
which the credit will be awarded;
[sbull] Additional information that either supports or suggest
modifications to the proposed performance criteria and presumptive
credit;
[sbull] Today's proposal requires systems using presedimentation to
sample after the presedimentation basin, and these systems are not
eligible to receive additional presumptive Cryptosporidium removal
credit for presedimentation. However, systems are also required to
collect samples prior to chemical treatment, and EPA recognizes that
some plants provide chemical treatment to water prior to, or during,
presedimentation. EPA requests comment on how this situation should be
handled under the LT2ESWTR.
[sbull] Whether and under what conditions factors like low
turbidity raw water, infrequent sludge removal, and wind would make
compliance with the 0.5 log turbidity removal requirement infeasible.
6. Bank Filtration
a. What is EPA proposing today? EPA is proposing to award
additional Cryptosporidium treatment credit (0.5 or 1.0 log) for
systems that implement bank filtration as a pre-treatment technique if
it meets the design criteria specified in this section. To be eligible
for credit as a pre-treatment technique, bank filtration collection
devices must meet the following criteria:
[sbull] Wells are drilled in an unconsolidated, predominantly sandy
aquifer, as determined by grain-size analysis of recovered core
material--the recovered core must contain greater than 10% fine-grained
material (grains less than 1.0 mm diameter) in at least 90% of its
length;
[sbull] Wells are located at least 25 feet (in any direction) from
the surface water source to be eligible for 0.5 log credit; wells
located at least 50 feet from the source surface water are eligible for
1.0 log credit;
[sbull] The wellhead must be continuously monitored for turbidity
to ensure that no system failure is occurring. If the monthly average
of daily maximum turbidity values exceeds 1 NTU then the system must
report this finding to the State. The system must also conduct an
assessment to determine the cause of the high turbidity levels in the
well and consult with the State regarding whether previously allowed
credit is still appropriate.
Systems using existing bank filtration as pretreatment to a
filtration plant at the time the systems are required to conduct
Cryptosporidium monitoring, as described in section IV.A, must sample
the well effluent for the purpose of determining bin classification.
Where bin classification is based on monitoring the well effluent,
systems are not eligible to receive additional credit for

[[Page 47692]]

bank filtration. In these cases, the performance of the bank filtration
process in reducing Cryptosporidium levels will be reflected in the
monitoring results and bin classification.
Systems using bank filtered water without additional filtration
typically must collect source water samples in the surface water (i.e.,
prior to bank filtration) to determine bin classification. This applies
to systems using bank filtration to meet the Cryptosporidium removal
requirements of the IESWTR or LT1ESWTR under the provisions for
alternative filtration demonstration in 40 CFR 141.173(b) or
141.552(a). Note that the proposed bank filtration criteria for
Cryptosporidium removal credit under the LT2ESWTR do not apply to
existing State actions to provide alternative filtration
Cryptosporidium removal credit for IESWTR or LT1ESWTR compliance.
In the case of systems that use GWUDI sources without additional
filtration and that meet all the criteria for avoiding filtration in 40
CFR 141.71, samples must be collected from the ground water (e.g., the
well). Further, such systems must comply with the requirements of the
LT2ESWTR that apply to unfiltered systems, as described in section
IV.B.
b. How was this proposal developed? This section describes the bank
filtration treatment process, provides more detail on the aquifer types
and ground water collection devices that are eligible for bank
filtration credit, and describes the data supporting the proposed
requirements.
Bank filtration is a water treatment process that makes use of
surface water that has naturally infiltrated into ground water via the
river bed or bank(s) and is recovered via a pumping well. Stream-bed
infiltration is typically enhanced by the pumping action of near-stream
wells (e.g., water supply, irrigation). Bank filtrate is water drawn
into a pumping well from a nearby surface water source which has
traveled through the subsurface, either vertically, horizontally or
both, mixing to some degree with other ground water. Through bank
filtration, microorganisms and other particles are removed by contact
with the aquifer materials.
The bank filtration removal process performs most efficiently when
the aquifer is comprised of granular materials with open pore-space for
water flow around the grains. In these granular porous aquifers, the
flow path is meandering, thereby providing ample opportunity for the
organism to come into contact with and attach to a grain surface.
Although detachment can occur, it typically occurs at a very slow rate
so that organisms remain attached to a grain for long periods. When
ground water travel times from source water to well are long or when
little or no detachment occurs, most organisms will become inactivated
before they can enter a well. Thus, bank filtration relies on removal,
but also, in some cases, on inactivation to protect wells from pathogen
contamination.
Only Wells Located in Unconsolidated, Predominantly Sandy Aquifers Are
Eligible
Only granular aquifers are eligible for bank filtration credit.
Granular aquifers are those comprised of sand, clay, silt, rock
fragments, pebbles or larger particles and minor cement. The aquifer
material is required to be unconsolidated, with subsurface samples
friable upon touch. Uncemented granular aquifers are typically formed
by alluvial or glacial processes. Such aquifers are usually identified
on a detailed geologic map (e.g., labeled as Quaternary alluvium).
Under today's proposal, a system seeking Cryptosporidium removal
credit must characterize the aquifer at the well site to determine
aquifer properties. At a minimum, the aquifer characterization must
include the collection of relatively undisturbed, continuous, core
samples from the surface to a depth equal to the bottom of the well
screen. The proposed site must have substantial core recovery during
drilling operations; specifically, the recovered core length must be at
least 90% of the total projected depth to the well screen.
Samples of the recovered core must be submitted to a laboratory for
sieve analysis to determine grain size distribution over the entire
recovered core length. Each sieve sample must be acquired at regular
intervals over the length of the recovered core, with one sample
representing a composite of each two feet of recovered core. A two-foot
sampling interval reflects the necessity to sample the core frequently
without imposing an undue burden. Because it is anticipated that wells
will range from 50 to 100 foot in depth, a two-foot sampling interval
will result in about 25 to 50 samples for analysis. Each sampled
interval must be examined to determine if more than ten percent of the
grains in that interval are less than 1.0 mm in diameter (18
sieve size). In the U.S. Department of Agriculture soil classification
system, the 18 sieve separates very coarse sands from coarse
sands. The length of core (based on the samples from two-foot
intervals) with more than ten percent of the grains less than 1.0 mm in
diameter must be summed to determine the overall core length with
sufficient fine-grained material so as to provide adequate removal. An
aquifer is eligible for removal credit if at least 90% of the sampled
core length contains sufficient fine-grained material as defined in
this section.
Cryptosporidium oocysts have a natural affinity for attaching to
fine-grained material. A study of oocyst removal in sand columns shows
greater oocyst removal in finer-grained sands than in coarser-grained
sands (Harter et al. 2000). The core sampling procedure described in
this section is designed to measure the proportion of fine-grained
sands (grains less than 1.0 mm in diameter) so as to ensure that a
potential bank filtration site is capable of retarding transport (or
removing) oocysts during ground water flow from the source surface
water to the water supply well. The value of 1.0 mm for the bounding
size of the sand grains was determined based on calculations performed
by Harter using data from Harter et al. (2000). Harter showed that, for
ground water velocities typical of a bank filtration site (1.5 to 15 m/
day), a typical bank filtration site composed of grains with a diameter
of 1.0 mm would achieve at least 1.0 log removal over a 50 foot
transport distance. Larger-sized grains would achieve less removal, all
other factors being equal.
Alluvial and glacial aquifers are complex mixtures of sand, gravel
and other sized particles. Particles of similar size are often grouped
together in the subsurface, due to sorting by flowing water that
carries and then deposits the particles. Where there exists significant
thickness of coarse-grained particles, such as gravels, with few finer
materials, there is limited opportunity for oocyst removal. When the
total gravel thickness, as measured in a core, exceeds 10%, it is more
likely (based on analysis of ground water flow within mixtures
containing differing-sized grains) that the gravel-rich intervals are
interconnected. Interconnected gravel can form a continuous,
preferential flow path from the source surface water to the water
supply well. Where such preferential flow paths exist, a preponderance
of the total ground water flow occurs within the preferential flow
path, ground water velocity is higher, and natural filtration is
minimal. A proposed bank filtration site is acceptable if at least 90%
of the core length contains grains with sufficient fine-grained
material (diameter less than 1.0 mm); that is, it is acceptable if the
core contains less than 10% gravel-rich intervals.
Aquifer materials with significant fracturing are capable of
transmitting

[[Page 47693]]

ground water at high velocity in a direct flow path with little time or
opportunity for die-off or removal of microbial pathogens. Consolidated
aquifers, fractured bedrock, and karst limestone are aquifers in which
surface water may enter into a pumping well by flow along a fracture, a
solution-enhanced fracture conduit, or other preferential pathway.
Microbial pathogens found in surface water are more likely to be
transported to a well via these direct or preferential pathways.
Cryptosporidium outbreaks have been associated with consolidated
aquifers, such as a fractured chalk aquifer (Willocks et al. 1998) or a
karst limestone (solution-enhanced fractured) aquifer (Bergmire-Sweat
et al. 1999). These outbreaks show that the oocyst removal performance
of consolidated aquifers is undermined by preferential water flow and
oocyst transport through rock fractures or through rock dissolution
zones. Wells located in these aquifers are not eligible for bank
filtration credit because the flow paths are direct and the average
ground water velocity is high, so that little inactivation or removal
would be expected. Therefore, only unconsolidated aquifer are eligible
for bank filtration oocyst removal credit.
A number of devices are used for the collection of ground water
including horizontal and vertical wells, spring boxes, and infiltration
galleries. Among these, only horizontal and vertical wells are eligible
for log removal credit. The following discussion presents
characteristics of ground water collection devices and the basis for
this proposed requirement.
Horizontal wells are designed to capture large volumes of surface
water recharge. They typically are constructed by the excavation of a
central vertical caisson with laterals that extend horizontally from
the caisson bottom in all directions or only under the riverbed.
Horizontal wells are usually shallower than vertical wells because of
the construction expense. Ground water flow to a horizontal well that
extends under surface water is predominantly downward. In contrast,
ground water flow to a vertical well adjacent to surface water may be
predominantly in the horizontal direction. Surface water may have a
short ground water flow path to a horizontal well if the well extends
out beyond the bank.
Hancock et al. (1998) analyzed samples from eleven horizontal wells
and found Cryptosporidium, Giardia or both in samples from five of
those wells. These data suggest that some horizontal wells may not be
capable of achieving effective Cryptosporidium removal by bank
filtration. Insufficient data are currently available to suggest that
horizontal well distances from surface water should be greater than
distances established for vertical wells. Two ongoing studies in
Wyoming (Clancy Environmental Consultants 2002) and Nebraska (Rice
2002) are collecting data at horizontal well sites.
A spring box is located at the ground surface and is designed to
contain spring outflow and protect it from surface contamination until
the water is utilized. Spring boxes are typically located where natural
processes have enhanced and focused ground water discharge into a
smaller area and at a faster volumetric flow rate than elsewhere (i.e.,
a spring). Often, localized fracturing or solution enhanced channels
are the cause of the focused discharge to the spring orifice. Fractures
and solution channels have significant potential to transport microbial
contaminants so that natural filtration may be poor. Thus, spring boxes
are not proposed to be eligible for bank filtration credit.
Cryptosporidium monitoring results (Hancock et al. 1998) and
outbreaks are used to evaluate ground water collection devices. Hancock
et al. sampled thirty five springs for Cryptosporidium oocysts and
Giardia cysts. Most springs were used as drinking water sources and
sampling was conducted to determine if the spring should be considered
as a GWUDI source. Cryptosporidium oocysts were found in seven springs;
Giardia cysts were found in five springs; and either oocysts or cysts
were found in nine springs (26%). A waterborne cryptosporidiosis
outbreak in Medford, Oregon (Craun et al. 1998) is associated with a
spring water supply collection device. Also, a more recent, smaller
outbreak of giardiasis in an Oregon campground is associated with a PWS
using a spring. The high percentage of springs contaminated with
pathogenic protozoan, the association with recent outbreaks, and an
apparent lack of bank filtration capability indicate that spring boxes
must not be eligible for bank filtration credit.
An infiltration gallery (or filter crib) is typically a slotted
pipe installed horizontally into a trench and backfilled with granular
material. The gallery is designed to collect water infiltrating from
the surface or to intercept ground water flowing naturally toward the
surface water (Symons et al. 2000). In some treatment plants, surface
water is transported to a point above an infiltration gallery and then
allowed to infiltrate. The infiltration rate may be manipulated by
varying the properties of the backfill or the nature of the soil-water
interface. Because the filtration properties of the material overlying
an infiltration gallery may be designed or purposefully altered to
optimize oocyst removal or for other reasons, this engineered system is
not bank filtration, which relies solely on the natural properties of
the system.
A 1992 cryptosporidiosis outbreak in Talent, Oregon was associated
with poor performance of an infiltration gallery underneath Bear Creek
(Leland et al. 1993). In this case, the ground water-surface water
interface and the engineered materials beneath did not sufficiently
reduce the high oocyst concentration present in the source water. The
association of an infiltration gallery with an outbreak, the design
that relies on engineered materials rather than the filtration
properties of natural filtration media, and the shallow depth of
constructed infiltration galleries, such that they typically are not
located greater than 25 feet from the surface and surface water
recharge, all indicate that infiltration galleries must not be eligible
for bank filtration credit.
EPA notes that under the demonstration of performance credit
described in section IV.C.17, States may consider awarding
Cryptosporidium removal credit to infiltration galleries where the
State determines, based on site-specific testing with a State-approved
protocol, that such credit is appropriate (i.e., that the process
reliably achieves a specified level of Cryptosporidium removal on a
continuing basis).
Wells Located 25 Feet From the Surface Water Source Are Eligible for
0.5 Log Credit; Wells Located 50 Feet From the Surface Water Source Are
Eligible for 1.0 Log Credit
A vertical or horizontal well located adjacent to a surface water
body is eligible for bank filtration credit if there is sufficient
ground water flow path length to effectively remove oocysts. For
vertical wells, the wellhead must be located at least 25 horizontal
feet from the surface water body for 0.5 log Cryptosporidium removal
credit and at least 50 horizontal feet from the surface water body for
1.0 log Cryptosporidium removal credit. For horizontal wells, the
laterals must be located at least 25 feet distant from the normal-flow
surface water riverbed for 0.5 log Cryptosporidium removal credit and
at least 50 feet distant from the normal-flow surface water riverbed
for 1.0 log Cryptosporidium removal credit.
The ground water flow path to a vertical well is the measured
distance from the edge of the surface water body, under high flow
conditions (determined by the mapped extent of the 100 year

[[Page 47694]]

floodplain elevation boundary or floodway, as defined in Federal
Emergency Management Agency (FEMA) flood hazard maps), to the wellhead.
The ground water flow path to a horizontal well is the measured
distance from the bed of the river under normal flow conditions to the
closest horizontal well lateral.
The floodway is defined by FEMA as the area of the flood plain
where the water is likely to be deepest and fastest. The floodway is
shown on FEMA digital maps (known as Q3 flood data maps), which are
available for 11,990 communities representing 1,293 counties in the
United States. Systems may identify the distance to surface water using
either the 100 year return period flood elevation boundary or by
determining the floodway boundary using methods similar to those used
in preparing FEMA flood hazard maps. The 100 year return period flood
elevation boundary is expected to be wider than the floodway but that
difference may vary depending on local conditions. Approximately 19,200
communities in the United States have flood hazard maps that show the
100 year return period flood elevation boundary. If local FEMA floodway
hazard maps are unavailable or do not show the 100 year flood elevation
boundary, then the utility must determine either the floodway or 100
year flood elevation boundary.
The separation distance proposed for Cryptosporidium removal credit
is based, in part, on measured data for the removal of oocyst surrogate
biota in full-scale field studies. A variety of surrogate and indicator
organisms were analyzed in each study evaluated for today's proposal.
However, only two non-pathogenic organisms, anaerobic clostridia spores
and aerobic endospores, are resistant to inactivation in the
subsurface, approximately similar in size and shape to oocysts, and
sufficiently ubiquitous in both surface water and ground water so that
log removal can be calculated during passage across the surface water--
ground water interface and during transport within the aquifer.
Anaerobic spores are typically estimated at about 0.3-0.4 [mu]m in
diameter as compared with 4-6 [mu]m for oocysts. Aerobic spores, such
as endospores of the bacterium Bacillus subtilis, are slightly larger
than anaerobic spores, typically 0.5 x 1.0 x 2.0 [mu]m in diameter
(Rice et al. 1996). Experiments conducted by injecting Bacillus
subtilis spores into a gravel aquifer show that they can be very mobile
in the subsurface environment (Pang et al. 1998). As presented in the
following discussion, available data indicate similar removal of both
aerobic and anaerobic spores, either during passage across the surface
water--ground water interface or during ground water flow. These data
suggest that anaerobic spores, like aerobic spores, may be suitable
surrogate measures of Cryptosporidium removal by bank filtration.
Available data establish that during bank filtration, significant
removal of anaerobic and aerobic spores can occur during passage across
the surface water-ground water interface, with lesser removal occurring
during ground water transport within the aquifer away from that
interface. The ground water-surface water interface is typically
comprised of finer grained material that lines the bottom of the
riverbed. Typically, the thickness of the interface is small, typically
a few inches to a foot. The proposed design criteria of 25 and 50 feet
for 0.5 and 1.0 log Cryptosporidium removal credit, respectively, are
based on EPA's analysis of pathogen and surrogate monitoring data from
bank filtration sites. Most of these data are from studies of aquifers
developed in Dutch North Sea margin sand dune fields and, therefore,
represent optimal removal conditions consistent with a homogenous, well
sorted (by wind), uniform sand filter.
Medema et al. (2000) measured 3.3 log removal of anaerobic spores
during transport over a 13 m distance from the Meuse River into
adjacent ground water. Arora et al. (2000) measured greater than 2.0
log removal of anaerobic spores during transport from the Wabash River
to a horizontal collector well. Havelaar et al. (1995) measured 3.1 log
removal of anaerobic spores during transport over a 30 m distance from
the Rhine River to a well and 3.6 log removal over a 25 m distance from
the Meuse River to a well. Schijven et al. (1998) measured 1.9 log
removal of anaerobic spores over a 2 m distance from a canal to a
monitoring well. Using aerobic spores, Wang et al. (2001) measured 1.8
log removal over a 2 foot distance from the Ohio river to a monitoring
well beneath the river.
During transport solely within shallow ground water (i.e., not
including removal across the surface water-ground water interface),
Medema et al. (2000) measured approximately 0.6 log removal of
anaerobic spores over a distance of 39 feet. Using aerobic spores, Wang
et al. (2001) measured 1.0 log removal of aerobic spores over a 48 foot
distance from a monitoring well beneath a river to a horizontal well
lateral.
At distances relatively far from an injection well in a deep,
anaerobic aquifer, thereby minimizing the effects of injection,
Schijven et al. measured negligible removal of anaerobic spores over a
30 m distance. However, few bank filtration systems occur in deeper,
anaerobic ground water so these data may not apply to a typical bank
filtration system in the United States.
These data demonstrate that during normal and low surface water
elevations, the surface water-ground water interface performs
effectively to remove microbial contamination. However, there will
typically be high water elevation periods during the year, especially
on uncontrolled rivers, that alter the nature and performance of the
interface due to flood scour, typically for short periods. During these
periods, lower removals would be expected to occur.
Averaging Cryptosporidium oocyst removal over the period of a year
requires consideration of both high and low removal periods. During
most of the year, high log removal rates would be expected to
predominate (e.g., 3.3 log removal over 42 feet) due to the removal
achieved during passage across the surface water-ground water
interface. During short periods of flooding, substantially lower
removal rates may occur (e.g., 0.5 log removal over 39 feet) due to
scouring of the riverbed and removal of the protective, fine-grained
material. By considering all time intervals with differing removal
rates over the period of a year, EPA is proposing that 0.5 log removal
over 25 feet (8 m) and 1.0 log removal over 50 feet (16 m) are
reasonable estimates of the average performance of a bank filtration
system over a year. This proposal is generally supported by colloidal
filtration theory modeling results using data characteristic of the
aquifers in Louisville and Cincinnati and column studies of oocyst
transport in sand (Harter et al. 2000).
Wells must be continuously monitored for turbidity
Under the Surface Water Treatment Rule (40 CFR 141.73(b)(1)) the
turbidity level of slow sand filtered water must be 1 NTU or less in
95% of the measurements taken each month. Turbidity sampling is
required once every four hours, but may be reduced to once per day
under certain conditions. Although slow sand filtration is not bank
filtration, similar pathogen removal mechanisms are expected to occur
in both processes. Just as turbidity monitoring is used to provide
assurance that the removal credit assigned to a slow sand filter is
being realized, EPA

[[Page 47695]]

is proposing continuous turbidity monitoring for all bank filtration
wells that receive credit.
If monthly average turbidity levels (based on daily maximum values
in the well) exceed 1 NTU, the system is required to report to the
State and present an assessment of whether microbial removal has been
compromised. If the State determines that microbial removal has been
compromised, the system must not receive credit for bank filtration
until the problem has been remediated. The turbidity performance
requirement for bank filtration is less strict than that for slow sand
filtration because, unlike slow sand filtration, bank filtration is a
pre-treatment technique followed by conventional or direct filtration.
BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TP11AU03.009

BILLING CODE 6560-50-C
In summary, EPA believes that the measured full-scale field data
from operating bank filtration systems, the turbidity monitoring
provision, and the design criteria for aquifer material, collection
device type, and setback distance, together provide assurance that the
presumptive log removal credit will be achieved by bank filtration
systems that conform to the requirements in today's proposal.
c. Request for comment. The Agency requests comment on the
following issues concerning bank filtration:
[sbull] The performance of bank filtration in removing
Cryptosporidium or surrogates to date at sites currently using this
technology (e.g. sites with horizontal wells).
[sbull] The use of other methods (e.g., geophysical methods such as
ground penetrating radar) to complement or supplant core drilling to
determine site suitability for bank filtration credit.
[sbull] The number of GWUDI systems in each State (i.e., the number
of systems having at least one GWUDI source) where bank filtration has
been utilized as the primary filtration barrier (e.g., no other
physical removal technologies follow); also, the method that was used
by the State to determine that each

[[Page 47696]]

system was achieving 2 log removal of Cryptosporidium.
[sbull] For GWUDI systems where natural or alternative filtration
(e.g. bank filtration or artificial recharge) is used in combination
with a subsequent filtration barrier (e.g., bag or cartridge filters)
to meet the 2 log Cryptosporidium removal requirement of the IESWTR or
LT1ESWTR, how much Cryptosporidium removal credit has the State awarded
(or is the State willing to grant if the bags/cartridges were found to
be achieving < 2.0 logs) for the natural or alternative filtration
process and how did the State determine this value?
[sbull] The proposed Cryptosporidium removal credit and associated
design criteria, including any additional information related to this
topic.
[sbull] Suitable separation distance(s) to be required between
vertical or horizontal wells and adjacent surface water.
[sbull] Testing protocols and procedures for making site specific
determinations of the appropriate level of Cryptosporidium removal
credit to award to bank filtration processes.
[sbull] Information on the data and methods suitable for predicting
Cryptosporidium removal based on the available data from surrogate and
indicator measurements in water collection devices.
[sbull] The applicability of turbidity monitoring or other process
monitoring procedures to indicate the ongoing performance of bank
filtration processes.
7. Lime Softening
a. What is EPA proposing today? Lime softening is a drinking water
treatment process that uses precipitation with lime and other chemicals
to reduce hardness and enhance clarification prior to filtration. Lime
softening can be categorized into two general types: (1) Single-stage
softening, which is used to remove calcium hardness and (2) two-stage
softening, which is used to remove magnesium hardness and greater
levels of calcium hardness. A single-stage softening plant includes a
primary clarifier and filtration components. A two-stage softening
plant also includes a secondary clarifier located between the primary
clarifier and filter. In some two-stage softening plants, a portion of
the flow bypasses the first clarifier.
EPA has determined that lime softening plants in compliance with
IESWTR or LT1ESWTR achieve a level of Cryptosporidium removal
equivalent to conventional treatment plants (i.e., average of 3 log).
Consequently, lime softening plants that are placed in Bins 2-4 as a
result of Cryptosporidium monitoring incur the same additional
treatment requirements as conventional plants. However, EPA is
proposing that two-stage softening plants be eligible for an additional
0.5 log Cryptosporidium treatment credit. To receive the 0.5 log
credit, the plant must have a second clarification stage between the
primary clarifier and filter that is operated continuously, and both
clarification stages must treat 100% of the plant flow. In addition, a
coagulant must be present in both clarifiers (may include metal salts,
polymers, lime, or magnesium precipitation).
b. How was this proposal developed? The lime softening process is
used to remove hardness, primarily calcium and magnesium, through
chemical precipitation followed by sedimentation and filtration. The
addition of lime increases pH, causing the metal ions to precipitate.
Other contaminants can coalesce with the precipitates and be removed in
the subsequent settling and filtration processes. While elevated pH has
been shown to inactivate some microorganisms like viruses (Battigelli
and Sobsey, 1993, Logsdon et al. 1994), current research indicates that
Cryptosporidium and Giardia are not inactivated by high pH (Logsdon et
al. 1994, Li et al. 2001). A two-stage lime softening plant has the
potential for additional Cryptosporidium removal because of the
additional sedimentation process.
Limited data are available on the removal of Cryptosporidium by the
lime softening treatment process. EPA has evaluated data from a study
by Logsdon et al. (1994), which investigated removal of Giardia and
Cryptosporidium in full scale lime softening plants. In addition, the
Agency has considered data provided by utilities on the removal of
aerobic spores in softening plants. These data are summarized in the
following paragraphs.
Logsdon et al. (1994) measured levels of Cryptosporidium and
Giardia in the raw, settled, and filtered water of 13 surface water
plants using lime softening. Cryptosporidium was detected in the raw
water at 5 utilities: one single-stage plant and four two-stage plants.
Using measured oocyst levels, Cryptosporidium removal by sedimentation
was 1.0 log in the single-stage plant and 1.1 to 2.3 log in the two-
stage plants. Cryptosporidium was found in two filtered water samples
of the single stage plant, leading to calculated removals from raw to
filtered water of 0.6 and 2.2 log. None of the two-stage plants had
Cryptosporidium detected in the filtered water. Based on detection
limits, calculated Cryptosporidium removals from raw to filtered water
in the two-stage plants ranged from 2.67 to 3.85
log.
Giardia removal across sedimentation was 0.9 log for a
single-stage plant and ranged from 0.8 to 3.2 log for two-stage plants,
based on measured cyst levels. Removal of Giardia from raw water
through filtration was calculated using detection limits as
1.5 log in a single-stage plant and ranged from
0.9 to 3.3 log in two-stage plants.
While results from the Logsdon et al. study are constrained by
sample number and method detection limits, they suggest that two-stage
softening plants may achieve greater removal of Cryptosporidium than
single-stage plants. The authors concluded that two stages of
sedimentation, each preceded by effective flocculation of particulate
matter, may increase removal of protozoa. Additionally, the authors
stated that consistent achievement of flocculation that results in
effective settling in each sedimentation basin is the key factor in
this treatment process.

Removal of Aerobic Spores by Softening Plants

Additional information on the microbial removal efficiency of the
lime softening process comes from data provided by softening plants on
removal of aerobic spores. While few treatment plants have sufficient
concentrations of oocysts to directly calculate a Cryptosporidium
removal efficiency, some plants have high concentrations of aerobic
spores in the raw water. Spores may serve as an indicator of
Cryptosporidium removal by sedimentation and filtration (Dugan et al.
2001).
The following two-stage softening plants provided data on removal
of aerobic spores: St. Louis, MO, Kansas City, MO, and Columbus, OH (2
plants). Cryptosporidium data were also collected at these utilities,
but it was not possible to calculate oocyst removal due to low raw
water detection rates. Data on removal of aerobic spores by these
softening plants is summarized in Table IV-14.

[[Page 47697]]

Table IV-14.--Summary of Aerobic Spore Removal Data From Softening Plants
----------------------------------------------------------------------------------------------------------------
Mean log removal of aerobic spores
-----------------------------------------------
Plant Primary Secondary
clarifier clarifier Across plant *
----------------------------------------------------------------------------------------------------------------
St. Louis....................................................... 1.7 1.1 3.8
Kansas City..................................................... 2.4 0 3.4
Columbus Plant 1................................................ 1.2 1.6 3.1
Columbus Plant 2................................................ 1.3 2.4 4.2
----------------------------------------------------------------------------------------------------------------
* Excludes removal in pre-sedimentation basins; calculated spore removal may underestimate actual removal due to
filter effluent levels below quantitation limits.

The City of St. Louis Water Division operates a two-stage lime
softening process preceded by presedimentation. Ferric sulfate and
polymer coagulants are added at various points in the process. St.
Louis collected Bacillus subtilis spore samples between June 1998 and
September 2000. During this time period, the mean spore concentration
entering the softening process (i.e., after presedimentation) was 8,132
cfu/100 mL. The log removal values shown in Table IV-14 are based on
average spore concentrations following primary clarification, secondary
clarification, and filtration. However, spore levels in some filtered
water samples were below the method detection limit, so that the true
mean spore removal across the plant may have been higher than indicated
by the calculated value.
The Kansas City Water Services Department plant includes two-stage
lime softening with pre-sedimentation and sludge recycle. Bacillus
subtilis spore data were collected from this plant during January
through November 2000. The mean spore concentration entering the lime
softening process (after presedimentation) was 5,965 cfu/100 mL. Mean
spore levels following primary clarification, secondary clarification,
and filtration were 21.1, 25.7, and 2.6 cfu/100 mL, respectively.
Corresponding log removal values are shown in Table IV-14. Note that
the average spore concentration in the effluent of the secondary
clarifier was essentially equivalent to the effluent of the primary
clarifier, indicating that little removal occurred in the secondary
clarifier. This result may have been due to the high removal achieved
in the primary clarifier and, consequently, the relatively low
concentration of spores entering the second clarifier. As with the St.
Louis plant, many of the filtered water observations were below method
detection limits, so actual log removal across the plant may have been
higher than the calculated value.
The City of Columbus operates two lime softening plants, each of
which has two clarification stages. Coagulant is added prior to the
first clarification stage but lime is not added until the second
clarifier (i.e., first clarifier is not a softening stage). Between
1997 and 2000, samples for total aerobic spores were collected
approximately monthly at each plant from raw water, following each
clarification basin, and after filtration. Mean spore concentrations in
the raw water sources for the two plants were 10,619 cfu/100 mL (Plant
1) and 22,595 cfu/100 mL (Plant 2). Mean log removals occurring in the
two clarification stages and across the plant are shown for each plant
in Table IV-14.
These data indicate that two-stage softening plants can remove high
levels of Cryptosporidium, and, in particular, that a second
clarification stage can achieve 0.5 log or greater removal. Three of
the four plants that provided data on removal of aerobic spores
achieved greater than 1 log reduction in the second clarifier. Kansas
City, the one plant which achieved little removal in the second
clarifier, achieved a mean 2.4 log removal in the primary clarifier.
This was approximately 1 log more reduction than achieved in the
primary clarifiers of the other three plants, so that the spore
concentration entering the second clarifier in Kansas City may have
been too low to serve as an indicator of removal efficiency.
Consequently, EPA has concluded that these data support an additional
Cryptosporidium treatment credit of 0.5 log for a two-stage softening
plant.
EPA is proposing as a condition of the 0.5 log additional credit
that a coagulant, which could include excess lime and soda ash or
precipitation of magnesium hydroxide, be present in both clarifiers.
This requirement is necessary to ensure that significant particulate
removal occurs in both clarification stages. Logsdon et al. (1994)
identified effective flocculation as being a key factor for removal of
protozoa in softening plants. Among the softening plants that provided
data on aerobic spore removal, St. Louis added ferric and polymer
coagulants at different points in the process, and the two Columbus
plants added lime to the second clarifier. Consequently, a requirement
that plants add a coagulant, which may be lime, in the secondary
clarifier is consistent with the data used to support the 0.5 log
additional credit.
The Science Advisory Board (SAB) reviewed the proposed
Cryptosporidium treatment credit for lime softening and supporting
information, as presented in the November 2001 pre-proposal draft of
the LT2ESWTR (USEPA 2001g). In written comments from a December 2001
meeting of the Drinking Water Committee, the SAB panel concluded that
both single- and two-stage softening generally outperform conventional
treatment due to the heavy precipitation that occurs. Further, the
panel found that 0.5 log of additional Cryptosporidium removal is an
average value for a two-stage lime softening plant. However, the SAB
stated that the additional credit for two-stage softening should be
given only if all the water passes through both stages. Today's
proposal is consistent with these recommendations by the SAB.
EPA notes that by including a presumptive credit for softening
plants, today's proposal differs from the Stage 2 M-DBP Agreement in
Principle, which recommends up to 1 log additional Cryptosporidium
treatment credit for softening plants based on demonstration of
performance, but no additional presumptive credit.
c. Request for comment. EPA requests comment on the proposed
criteria for awarding credit to lime softening plants. EPA would
particularly appreciate comment on the following issues:
[sbull] Whether the information and analyses presented in this
proposal supports an additional 0.5 log credit for two-stage softening,
and the associated criteria necessary for credit.
[sbull] Additional information that either support or suggest
modifications to the proposed criteria and credit.
8. Combined Filter Performance
a. What is EPA proposing today? This toolbox component will grant
additional credit towards Cryptosporidium

[[Page 47698]]

treatment requirements to certain plants that maintain finished water
turbidity at levels significantly lower than currently required. EPA is
proposing to award an additional 0.5 log Cryptosporidium treatment
credit to conventional and direct filtration plants that demonstrate a
turbidity level in the combined filter effluent (CFE) less than or
equal to 0.15 NTU in at least 95 percent of the measurements taken each
month. Compliance with this criterion must be based on measurements of
the CFE every four hours (or more frequently) that the system serves
water to the public. This credit is not available to membrane, bag/
cartridge, slow sand, or DE plants, due to the lack of documented
correlation between effluent turbidity and Cryptosporidium removal in
these processes.
b. How was this proposal developed? Turbidity is an optical
property measured from the amount of light scattered by suspended
particles in a solution. It is a method defined parameter that can
detect the presence of a wide variety of particles in water (e.g.,
clay, silt, mineral particles, organic and inorganic matter, and
microorganisms), but it cannot provide specific information on particle
type, number, or size. Turbidity is used as an indicator of raw and
finished water quality and treatment performance. Turbidity spikes in
filtered water indicate a potential for breakthrough of pathogens.
Under the IESWTR and LT1ESWTR, combined filter effluent turbidity
in conventional and direct filtration plants must be less than or equal
to 0.3 NTU in 95% of samples taken each month and must never exceed 1
NTU. These plants are also required to conduct continuous monitoring of
turbidity for each individual filter, and provide an exceptions report
to the State when certain criteria for individual filter effluent
turbidity are exceeded (described in 63 FR 69487, December 16, 1998)
(USEPA 1998a).
The Stage 2 M-DBP Advisory Committee recommended that systems
receive an additional 0.5 log Cryptosporidium removal credit for
maintaining 95th percentile combined filter effluent turbidity below
0.15 NTU, which is one half of the current required level of 0.3 NTU.
In considering the technical basis to support this recommendation, EPA
has reviewed studies that evaluated the efficiency of granular media
filtration in removing Cryptosporidium when operating at different
effluent turbidity levels.
For the IESWTR, EPA estimated that plants would target filter
effluent turbidity in the range of 0.2 NTU in order to ensure
compliance with a turbidity standard of 0.3 NTU. Similarly, EPA has
estimated that plants relying on meeting a turbidity standard of 0.15
NTU in 95% of samples will consistently operate below 0.1 NTU in order
to ensure compliance. Consequently, to assess the impact of compliance
with the lower finished water turbidity standard, EPA compared
Cryptosporidium removal efficiency when effluent turbidity is below 0.1
NTU with removal efficiency when effluent turbidity is in the range of
0.1 to 0.2 NTU. Results from applicable studies are summarized in Table
IV-15 and are discussed in the following paragraphs.

Table IV-15.--Studies of Cryptosporidium Removal at Different Effluent Turbidity Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average of log Filtered effluent
Microorganism removals turbidity Experiment design Researcher
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cryptosporidium..................... 4.39 <=0.1 NTU.............. Pilot-scale.................... Patania et al. (1995).
3.55 0.1 and
<=0.2 NTU
Giardia............................. 4.23 <=0.1 NTU
3.22 0.1 and
<=0.2 NTU
Cryptosporidium..................... 4.09 <=0.1 NTU.............. Bench-scale.................... Emelko et al. (1999).
3.58 0.1 and
<=0.2 NTU
Cryptosporidium..................... 3.76 <=0.1 NTU Pilot-scale.................... Dugan et al. (2001).
2.56 0.1 and
<=0.2 NTU
--------------------------------------------------------------------------------------------------------------------------------------------------------

Patania et al. (1995) conducted pilot-scale studies at four
locations to evaluate the removal of seeded Cryptosporidium and
Giardia, turbidity, and particles. Treatment processes, coagulants, and
coagulant doses differed among the four locations. Samples of filter
effluent were taken at times of stable operation and filter maturation.
Analysis of summary data from the seeded runs at all locations shows
that average Cryptosporidium removal was greater by more than 0.5 log
when effluent turbidity was less than 0.1 NTU, in comparison to removal
with effluent turbidity in the range 0.1 to 0.2 NTU (see Table IV-15).
Emelko et al. (1999) used a bench scale dual media filter to study
Cryptosporidium removal during both optimal and challenged operating
conditions. Water containing a suspension of kaolinite (clay) was
spiked with oocysts, coagulated in-line with alum, and filtered. Oocyst
removal was evaluated during stable operation when effluent turbidity
was below 0.1 NTU. Removal was also measured after a hydraulic surge
that caused process upset, and with coagulant addition terminated.
These later two conditions resulted in effluent turbidities greater
than 0.1 NTU and decreased removal of Cryptosporidium. As shown in
Table IV-15, average removal of Cryptosporidium during periods with
effluent turbidity below 0.1 NTU was approximately 0.5 log greater than
when effluent turbidity was between 0.1 to 0.2 NTU.
Dugan et al. (2001) evaluated Cryptosporidium removal in a pilot
scale conventional treatment plant. Sixteen filtration runs seeded with
Cryptosporidium were conducted at different raw water turbidities and
coagulation conditions. Eleven of the runs had an effluent turbidity
below 0.1 NTU, and five runs had effluent turbidity between 0.1 and 0.2
NTU. For runs where the calculated Cryptosporidium removal was
concentration limited (i.e., effluent values were non-detect), the
method detection limit was used to calculate the values shown in Table
IV-15. Using this conservative estimate, average Cryptosporidium
removal with effluent turbidity below 0.1 NTU exceeded by more than 1
log the average removal observed with effluent turbidity between 0.1 to
0.2 NTU.
In summary, these three studies all support today's proposal in
showing that plants consistently operating below 0.1 NTU can achieve an
additional 0.5 log or greater removal of Cryptosporidium than when
operating between 0.1 and 0.2 NTU. Because EPA expects plants relying
on compliance with a 0.15 NTU standard will consistently operate below
0.1 NTU, the

[[Page 47699]]

Agency has determined it is appropriate to propose an additional 0.5
log treatment credit for plants meeting this standard.
The SAB reviewed the proposed additional 0.5 log Cryptosporidium
removal credit for systems maintaining very low CFE turbidity, as
presented in the November 2001 pre-proposal draft of the LT2ESWTR
(USEPA 2001g). The SAB also reviewed a potential additional 1.0 log
Cryptosporidium removal credit for systems achieving very low
individual filter effluent (IFE) turbidity, which is addressed in
section IV.C.16 of today's proposal.
In written comments from a December 2001 meeting of the Drinking
Water Committee, the SAB panel stated that additional credit for lower
finished water turbidity is consistent with what is known in both pilot
and full-scale operational experiences for Cryptosporidium removal.
Recognizing that IESWTR requirements for lowering turbidity in the
treated water will result in lower concentrations of Cryptosporidium,
the panel affirmed that even further lowering of turbidity will result
in further reductions in Cryptosporidium in the filter effluent.
However, the SAB concluded that limited data were presented to show the
exact removal that can be achieved, and recommended that no additional
credit be given to plants that demonstrate CFE turbidity of 0.15 NTU or
less. The SAB recommended that 0.5 log credit be given to plants
achieving IFE turbidity in each filter less than 0.15 NTU in 95% of
samples each month.
In responding to this recommendation from the SAB, EPA acknowledges
the difficulty in precisely quantifying Cryptosporidium removal through
filtration based on effluent turbidity levels. Nevertheless, EPA finds
that available data consistently show that removal of Cryptosporidium
is increased by 0.5 log or greater when filter effluent turbidity is
reduced to levels reflecting compliance with a 0.15 NTU standard, in
comparison to compliance with a 0.3 NTU standard. Consequently, EPA has
concluded that it is appropriate to propose this 0.5 log presumptive
treatment credit for systems achieving very low CFE turbidity.
Measurement of Low Level Turbidity
Another important aspect of proposing to award additional removal
credit for lower finished water turbidity is the performance of
turbidimeters in measuring turbidity below 0.3 NTU. The following
paragraphs summarize results from several studies that evaluated low
level measurement of turbidity by different on-line and bench top
instruments. Note that because compliance with the CFE turbidity limit
is based on 4-hour readings, either on-line or bench top turbidimeters
may be used. EPA believes that results from these studies indicate that
currently available turbidity monitoring equipment is capable of
reliably assessing turbidity at levels below 0.1 NTU, provided
instruments are well calibrated and maintained.
The 1997 NODA for the IESWTR (67 FR 59502, Nov. 3, 1997) (USEPA
1997a) discusses issues relating to the accuracy and precision of low
level turbidity measurements. This document cites studies (Hart et al.
1992, Sethi et al. 1997) suggesting that large tolerances in instrument
design criteria have led to turbidimeters that provide different
turbidity readings for a given suspension.
At the time of IESWTR NODA, EPA had conducted performance
evaluation (PE) studies of turbidity samples above 0.3 NTU. A
subsequent PE study (USEPA 1998e), labeled WS041, was carried out to
address concern among the Stage 1 M-DBP Federal Advisory Committee
regarding the ability to reliably measure lower turbidity levels. The
study involved distribution of different types of laboratory prepared
standard solutions with reported turbidity values of 0.150 NTU or 0.160
NTU. The results of this study are summarized in Table IV-16.
BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TP11AU03.010

BILLING CODE 6560-50-C
The data summarized in Table IV-16 indicate a positive bias for all
instruments when compared against a reported ``true value.'' On-line
instruments in this study had a larger positive bias and higher
standard deviation (RSD approximately 50 percent). The positive bias is
consistent with previous PE studies (USEPA 1998e) and suggests that
error in turbidimeter readings may be generally conservative (i.e.,
systems will operate

[[Page 47700]]

at lower than required effluent turbidity levels).
Letterman et al. (2001) evaluated the effect of turbidimeter design
and calibration methods on inter-instrument performance, comparing
bench top to on-line instruments and instruments within each of those
categories from different manufacturers. The study used treated water
collected from the filter effluent of water treatment plants. Reported
sample turbidity values ranged from 0.05 to 1 NTU. Samples were
analyzed in a laboratory environment. The results are consistent with
those of the WS041 study, specifically the positive bias of on-line
instruments. However, Letterman et al. found generally poor agreement
among different on-line instruments and between bench-top and on-line
instruments. The authors also observed that results were independent of
the calibration method, though certain experiments suggested that
analyst experience may have some effect on turbidity readings from
bench-top instruments.
Sadar (1999) conducted an intra-instrument study of low level
turbidity measurements among instruments from the same manufacturer.
This study was performed under well-controlled laboratory conditions.
Intra-instrument variation among different models and between bench top
and on-line instruments occurred but at significantly lower levels than
the Letterman et al. inter-instrument study. Newer instruments also
tended to read lower than older instruments, which the author
attributed to a reduction in stray light and lower sensitivities in the
newer instruments. Sadar also found a generally positive bias when
comparing on-line to bench-top and when comparing all instruments to a
prepared standard.
The American Society for Testing and Materials (ASTM) has issued
standard test methods for measurement of turbidity below 5 NTU by on-
line (ASTM 2001) and static (ASTM 2003) instrument modes. The methods
specify that the instrument should permit detection of turbidity
differences of 0.01 NTU or less in waters having turbidities of less
than 1.00 NTU (ASTM 2001) and 5.0 NTU (ASTM 2003), respectively. Inter-
laboratory study data included with the method for a known turbidity
standard of 0.122 NTU show an analyst relative deviation of 7.5% and a
laboratory relative deviation of 16% (ASTM 2003).
In summary, the data collected in these studies of turbidity
measurement indicate that currently available monitoring equipment can
reliably measure turbidity at levels of 0.1 NTU and lower. However,
this requires rigorous calibration and verification procedures, as well
as diligent maintenance of turbidity monitoring equipment (Burlingame
1998, Sadar 1999). Systems that pursue additional treatment credit for
lower finished water turbidity must develop the procedures necessary to
ensure accurate and reliable measurement of turbidity at levels of 0.1
NTU and less. EPA guidance for the microbial toolbox will provide
direction to water systems on developing these procedures.
c. Request for comment. EPA invites comment on the following issues
regarding the proposed Cryptosporidium treatment credit for combined
filter performance:
[sbull] Do the studies cited here support awarding 0.5 log credit
for CFE <= 0.15 NTU 95% of the time?
[sbull] Does currently available turbidity monitoring technology
accurately distinguish differences between values measured near 0.15
NTU?
9. Roughing Filter
a. What is EPA proposing today? The Stage 2 M-DBP Agreement in
Principle recommends a 0.5 log presumptive credit towards additional
Cryptosporidium treatment requirements for roughing filters. However,
the Agreement further specifies that EPA is to determine the design and
implementation criteria under which the credit would be awarded. Upon
subsequent review of available literature, EPA is unable to identify
design and implementation conditions for roughing filters that would
provide reasonable assurance of achieving a 0.5 log removal of oocysts.
Consequently, EPA is not proposing presumptive credit for
Cryptosporidium removal by roughing filters. Today's proposal does,
though, include a 0.5 log credit for a second granular media filter
following coagulation and primary filtration (see section IV.C.13).
b. How was this proposal developed? Roughing filtration is a
technique used primarily in developing countries to remove solids from
high turbidity source waters prior to treatment with slow sand filters.
Typically, roughing filters consist of a series of sedimentation tanks
filled with progressively smaller diameter media in the direction of
flow. The media can be gravel, plastic, crushed coconut, rice husks, or
a similar locally available material. The flow direction in roughing
filters can be either horizontal or vertical, and vertical roughing
filters can be either upflow or downflow. The media in the tanks
effectively reduce the vertical settling distance of particles to a
distance of a few millimeters. As sediment builds on the media, it
eventually sloughs off and begins to accumulate in the lower section of
the filter, while simultaneously regenerating the upper portions of the
filter. The filters require periodic cleaning to remove the collected
silt.
Review of the scientific and technical literature pertaining to
roughing filters has identified no information on removal of
Cryptosporidium. Information is available on removal of suspended
solids, turbidity, particles, fecal coliforms and some algae, but none
of these has been demonstrated to be an indicator of Cryptosporidium
removal by roughing filters. Moreover, roughing filters are not
preceded by a coagulation step, and studies have found that some
potential surrogates, such as aerobic spores, are not conservative
indicators of Cryptosporidium removal by filtration when a coagulant is
not present (Yates et al. 1998, Dugan et al. 2001). Thus, it is unclear
how to relate results from studies of the removal of other particles by
roughing filters to potential removal of Cryptosporidium.
In addition, some studies have observed very poor removal of
Cryptosporidium by rapid sand filters when a coagulant is not used
(Patania et al. 1995, Huck et al. 2000). Based on these findings, it is
expected that there would be situations where a roughing filter would
not achieve 0.5 log Cryptosporidium removal. Because available data are
insufficient to determine the conditions that would be necessary for a
roughing filter to achieve 0.5 log Cryptosporidium removal, EPA is
unable to propose this credit. The following discussion describes four
studies that analyzed the effectiveness of roughing filters for
removing solids, turbidity, particles, fecal coliforms, and algae.
Wegelin et al. (1987) conducted pilot-scale studies on the use of
horizontal roughing filters to reduce solids, turbidity, and particles.
Testing was performed to determine the influence of different design
parameters on filter performance. Data from the parameter testing was
used to establish an empirical model to simulate filtrate quality as a
function of filter length and time for a given filter configuration.
Using the mathematical model, the researchers found that long filters
(10 m) at low filtration rates (0.5 m/h) were capable of reducing high
suspended solids concentrations (1000 mg/L TSS) down to less than 3 mg/
L.
Further work by Wegelin (1988) evaluated roughing filters as
pretreatment for slow sand filters for

[[Page 47701]]

waters with variable and seasonably high suspended solids
concentrations. This study collected data on roughing filters in Peru,
Colombia, Sudan, and Ghana. Table IV-17 summarizes data for three of
the roughing filters. These filters were capable of reducing peak
turbidities by 80 to 90 percent. Further, the Peruvian and Colombian
filters reduced fecal coliforms by 77 and 89 percent, respectively. The
Sudanese filter may have removed around 90 percent of the fecal
coliforms, but specific values were not given. Data collected from
roughing filters in Ghana on algae removal indicate that the
Merismopedia (0.5 [mu]m) and Chlorophyta (2-10 [mu]m), which are
comparable in size to Cryptosporidium oocysts, were completely removed
from the water in mature filters, and that some removal of Chlorophyta,
but not Merismopedia, occurred in filters after three days of
operation. However, the removal of these organisms has not been
correlated with Cryptosporidium oocyst removal.

Table IV-17.--Roughing Filter Data From Wegelin, 1988
----------------------------------------------------------------------------------------------------------------
Location Azpita, Peru El Retiro, Colombia Blue Nile Health Project, Sudan
----------------------------------------------------------------------------------------------------------------
Roughing Filter Type............ Downflow........... Upflow (multi-layer Horizontal-flow.
filter).
Filtration Rate................. 0.30 m/h (0.98 ft/ 0.74 m/h (2.43 f/ 0.3 m/h (0.98 ft/hr).
hr). hr).
Design Capacity................. 35 m³/d............ 790 m³/d........... 5 m³/d.
---------------------------------
Turbidity (NTU)
----------------------------------------------------------------------------------------------------------------
Raw Water....................... 50-200............. 10-150............. 40-500
Roughing Filter Effluent........ 15-40.............. 5-15............... 5-50
---------------------------------
Fecal Coliforms (/100 mL)
----------------------------------------------------------------------------------------------------------------
Raw Water....................... 700................ 16,000............. 300
Roughing Filter Effluent........ 160................ 1,680.............. <25
----------------------------------------------------------------------------------------------------------------

oller (1993) details the mechanisms of particle removal that occur
in roughing filters. The conclusions are similar to those drawn by
Wegelin et al. (1987). Particle analysis reviewed by Boller indicates
that after seven days of operation, the four stage pilot filter
utilized by Wegelin et al. (1987) removed more than 98 percent of
particles sized 1.1 [mu]m, and greater than 99 percent of particles
sized 3.6 [mu]m. After 62 days, only 80 percent of particles sized 1.1
[mu]m were removed, while 90 percent of particles sized 3.6 [mu]m were
removed. Boller did not give the solids loading on the tested filter,
and particle removal was not correlated to Cryptosporidium oocyst
removal.
Collins et al. (1994) investigated solids and algae removal with
pilot scale vertical downflow roughing filters. Gravel media size,
filter depth, and flow rate were varied to determine which design
variables had the greatest effect on filter performance. Results
indicated that the most influential design parameters for removing
solids from water, in order of importance, were filter length, gravel
size, and hydraulic flow rate. For algae removal, the most influential
design parameters were hydraulic flow rate, filter length, and gravel
size. Solids removal was better in filters that had been ripened with
algae for 5-7 days. However, extrapolation of these results to
Cryptosporidium removal could not be made.
c. Request for comment. The Agency requests comment on the
information that has been presented about roughing filters, and
specifically the question of whether and under what conditions roughing
filters should be awarded a 0.5 log credit for removal of
Cryptosporidium. EPA also requests information on specific studies of
Cryptosporidium oocyst removal by roughing filters, or from studies of
the removal of surrogate parameters that have been shown to correlate
with oocyst removal in roughing filters.
10. Slow Sand Filtration
a. What is EPA proposing today? Slow sand filtration is defined in
40 CFR 141.2 as a process involving passage of raw water through a bed
of sand at low velocity (generally less than 0.4 m/h) resulting in
substantial particulate removal by physical and biological mechanisms.
Today's proposal allows systems using slow sand filtration as a
secondary filtration step following a primary filtration process (e.g.,
conventional treatment) to receive an additional 2.5 log
Cryptosporidium treatment credit. There must be no disinfectant
residual in the influent water to the slow sand filtration process to
be eligible for credit.
Note that this proposed credit differs from the credit proposed for
slow sand filtration as a primary filtration process. EPA has
concluded, based on treatment studies described in section III.D, that
plants using well designed and well operated slow sand filtration as a
primary filtration process can achieve an average Cryptosporidium
removal of 3 log (Schuler and Ghosh, 1991, Timms et al. 1995, Hall et
al. 1994). Consequently, as described in section IV.A, EPA is proposing
that plants using slow sand filtration as a primary filtration process
receive a 3 log credit towards Cryptosporidium treatment requirements
associated with Bins 2-4 under the LT2ESWTR (i.e., credit equivalent to
a conventional treatment plant).
The proposed 2.5 log credit for slow sand filtration as part of the
microbial toolbox applies only when it is used as a secondary
filtration step, following a primary filtration process like
conventional treatment. While the removal mechanisms that make slow
sand filtration effective as a primary filtration process would also be
operative when used as a secondary filtration step, EPA has little data
on this specific application. The Agency is proposing 2.5 log credit
for slow sand filtration as a secondary filtration step, in comparison
to 3 log credit as a primary filtration process, as a conservative
measure reflecting greater uncertainty. In addition, the proposed 2.5
log credit for slow sand filtration as part of the microbial toolbox is
consistent with the recommendation in the Stage 2 M-DBP Agreement in
Principle.
b. How was this proposal developed? The Stage 2 M-DBP Agreement in
Principle recommends that slow sand filtration receive 2.5 log or
greater Cryptosporidium treatment credit when used in addition to
existing treatment that achieves compliance with the

[[Page 47702]]

IESWTR or LT1ESWTR. Slow sand filtration is not typically used as a
secondary filtration step following conventional treatment or other
primary filtration processes of similar efficacy. However, EPA expects
that slow sand filtration would achieve significant removal of
Cryptosporidium in such a treatment train.
While there is a significant body of data demonstrating the
effectiveness of slow sand filtration for Cryptosporidium removal as a
primary filtration process, as described in section III.D, EPA has
limited data on the effectiveness of slow sand filtration when used as
a secondary filtration step. Hall et al. (1994) evaluated oocyst
removal for a pilot scale slow sand filter following a primary
filtration process identified as a rapid gravity filter. The combined
treatment train of a primary filtration process followed by slow sand
filtration achieved greater than 3 log Cryptosporidium removal in three
of five experimental runs, while approximately 2.5 log reduction was
observed in the other two runs. In comparison, Hall et al. (1994)
reported slow sand filtration alone to achieve at least a 3 log removal
of oocysts in each of four experimental runs when not preceded by a
primary filtration process. The authors offered no explanation for
these results, but measured oocyst removals may have been impacted by
limitations with the analytical method.
Removal of microbial pathogens in slow sand filters is complex and
is believed to occur through a combination of physical, chemical, and
biological mechanisms, both on the surface (schmutzdecke) and in the
interior of the filter bed. It is unknown if the higher quality of the
water that would be influent to a slow sand filter when used as a
secondary filtration step would impact the efficiency of the filter in
removing Cryptosporidium. Based on the limited data on the performance
of slow sand filtration as a secondary filtration step, and in
consideration of the recommendation of the Advisory Committee, EPA is
proposing only a 2.5 log additional Cryptosporidium treatment credit
for this application.
c. Request for comment. The Agency requests comment on whether the
available data are adequate to support awarding a 2.5 log
Cryptosporidium removal credit for slow sand filtration applied as a
secondary filtration step, along with any additional information
related to this application.
11. Membrane Filtration
a. What is EPA proposing today? EPA is proposing criteria for
awarding credit to membrane filtration processes for removal of
Cryptosporidium. To receive removal credit, the membrane filtration
process must: (1) Meet the basic definition of a membrane filtration
process, (2) have removal efficiency established through challenge
testing and verified by direct integrity testing, and (3) undergo
periodic direct integrity testing and continuous indirect integrity
monitoring during use. The maximum removal credit that a membrane
filtration process is eligible to receive is equal to the lower value
of either:

--The removal efficiency demonstrated during challenge testing OR
--The maximum log removal value that can be verified through the direct
integrity test (i.e., integrity test sensitivity) used to monitor the
membrane filtration process.

By the criteria in today's proposal, a membrane filtration process
could potentially meet the Bin 4 Cryptosporidium treatment requirements
of this proposal. These criteria are described in more detail below.
EPA is developing a Membrane Filtration Guidance Manual that provides
additional information and procedures for meeting these criteria (USEPA
2003e). A draft of this guidance is available in the docket for today's
proposal (http://www.epa.gov/edocket/).
Definition of a Membrane Filtration Process
For the purpose of this proposed rule, membrane filtration is
defined as a pressure or vacuum driven separation process in which
particulate matter larger than 1 [mu]m is rejected by a nonfibrous,
engineered barrier, primarily through a size exclusion mechanism, and
which has a measurable removal efficiency of a target organism that can
be verified through the application of a direct integrity test. This
definition is intended to include the common membrane technology
classifications: microfiltration (MF), ultrafiltration (UF),
nanofiltration (NF), and reverse osmosis (RO). MF and UF are low-
pressure membrane filtration processes that are primarily used to
remove particulate matter and microbial contaminants. NF and RO are
membrane separation processes that are primarily used to remove
dissolved contaminants through a variety of mechanisms, but which also
remove particulate matter via a size exclusion mechanism.
In today's proposal, the critical distinction between membrane
filtration processes and bag and cartridge filters, described in
section IV.C.12, is that the integrity of membrane filtration processes
can be directly tested. Based on this distinction, EPA is proposing
that membrane material configured into a cartridge filtration device
that meets the definition of membrane filtration and that can be direct
integrity tested according to the criteria specified in this section is
eligible for the same removal credit as a membrane filtration process.
Membrane devices can be designed in a variety of configurations
including hollow-fiber modules, hollow-fiber cassettes, spiral-wound
elements, cartridge filter elements, plate and frame modules, and
tubular modules among others. In today's proposal, the generic term
module is used to refer to all of these various configurations and is
defined as the smallest component of a membrane unit in which a
specific membrane surface area is housed in a device with a filtrate
outlet structure. A membrane unit is defined as a group of membrane
modules that share common valving that allows the unit to be isolated
from the rest of the system for the purpose of integrity testing or
other maintenance.
Challenge Testing
A challenge test is defined as a study conducted to determine the
removal efficiency (i.e., log removal value) of the membrane filtration
media. The removal efficiency demonstrated during challenge testing
establishes the maximum removal credit that a membrane filtration
process is eligible to receive, provided this value is less than or
equal to the maximum log removal value that can be verified by the
direct integrity test (as described in the following subsection).
Challenge testing is a product specific rather than a site specific
requirement. At the discretion of the State, data from challenge
studies conducted prior to promulgation of this regulation may be
considered in lieu of additional testing. However, the prior testing
must have been conducted in a manner that demonstrates a removal
efficiency for Cryptosporidium commensurate with the treatment credit
awarded to the process. Guidance for conducting challenge testing to
meet the requirements of the rule is provided in the Membrane
Filtration Guidance Manual (USEPA 2003e). Challenge testing must be
conducted according to the following criteria:
[sbull] Challenge testing must be conducted on a full-scale
membrane module identical in material and construction to the membrane
modules proposed for use in full-scale treatment facilities.
Alternatively, challenge testing may be conducted on a smaller membrane
module, identical in material and similar in construction to the full-

[[Page 47703]]

scale module, if testing meets the other requirements listed in this
section.
[sbull] Challenge testing must be conducted using Cryptosporidium
oocysts or a surrogate that has been determined to be removed no more
efficiently than Cryptosporidium oocysts. The organism or surrogate
used during challenge testing is referred to as the challenge
particulate. The concentration of the challenge particulate must be
determined using a method capable of discretely quantifying the
specific challenge particulate used in the test. Thus, gross water
quality measurements such as turbidity or conductivity cannot be used.
[sbull] The maximum allowable feed water concentration used during
a challenge test is based on the detection limit of the challenge
particulate in the filtrate, and is determined according to the
following equation:

Maximum Feed Concentration = 3.16 x 10\6\ x (Filtrate Detection Limit)

This will allow the demonstration of up to 6.5 log removal during
challenge testing if the challenge particulate is removed to the
detection limit.
[sbull] Challenge testing must be conducted under representative
hydraulic conditions at the maximum design flux and maximum design
system recovery as specified by the manufacturer. Flux is defined as
the flow per unit of membrane area. Recovery is defined as the ratio of
filtrate volume produced by a membrane to feed water volume applied to
a membrane over the course of an uninterrupted operating cycle. An
operating cycle is bounded by two consecutive backwash or cleaning
events. In the context of this rule, recovery does not consider losses
that occur due to the use of filtrate in backwashing or cleaning
operations.
[sbull] Removal efficiency of a membrane filtration process is
determined from the results of the challenge test, and expressed in
terms of log removal values as defined by the following equation:

LRV = LOG10(Cf)-LOG10(Cp)

where LRV = log removal value demonstrated during challenge testing;
Cf = the feed concentration used during the challenge test;
and Cp = the filtrate concentration observed during the
challenge test. For this equation to be valid, equivalent units must be
used for the feed and filtrate concentrations. If the challenge
particulate is not detected in the filtrate, then the term
Cp is set equal to the detection limit. A single LRV is
calculated for each membrane module evaluated during the test.
[sbull] The removal efficiency of a membrane filtration process
demonstrated during challenge testing is expressed as a log removal
value (LRVC-Test). If fewer than twenty modules are tested,
then LRVC-Test is assigned a value equal to the lowest of
the representative LRVs among the various modules tested. If twenty or
more modules are tested, then LRVC-Test is assigned a value
equal to the 10th percentile of the representative LRVs among the
various modules tested. The percentile is defined by [i/(n+1)] where i
is the rank of n individual data points ordered lowest to highest. It
may be necessary to calculate the 10th percentile using linear
interpolation.
[sbull] A quality control release value (QCRV) must be established
for a non-destructive performance test (e.g., bubble point test,
diffusive airflow test, pressure/vacuum decay test) that demonstrates
the Cryptosporidium removal capability of the membrane module. The
performance test must be applied to each production membrane module
that did not undergo a challenge test in order to verify
Cryptosporidium removal capability. Production membrane modules that do
not meet the established QCRV are not eligible for the removal credit
demonstrated during challenge testing.
[sbull] Any significant modification to the membrane filtration
device (e.g., change in the polymer chemistry of the membrane) requires
additional challenge testing to demonstrate removal efficiency of the
modified module and to define a new QCRV for the nondestructive
performance test.
Direct Integrity Testing
In order to receive removal credit for Cryptosporidium, the removal
efficiency of a membrane filtration process must be routinely verified
through direct integrity testing. A direct integrity test is defined as
a physical test applied to a membrane unit in order to identify and
isolate integrity breaches. An integrity breach is defined as one or
more leaks that could result in contamination of the filtrate. The
direct integrity test method must be applied to the physical elements
of the entire membrane unit including membranes, seals, potting
material, associated valving and piping, and all other components which
under compromised conditions could result in contamination of the
filtrate.
The direct integrity tests commonly used at the time of this
proposal include those that use an applied pressure or vacuum (such as
the pressure decay test and diffusive airflow test), and those that
measure the rejection of a particulate or molecular marker (such as
spiked particle monitoring). Today's proposal does not stipulate the
use of a particular direct integrity test. Instead, the direct
integrity test must meet performance criteria for resolution,
sensitivity, and frequency.
Resolution is defined as the smallest leak that contributes to the
response from a direct integrity test. Any direct integrity test
applied to meet the requirements of this proposed rule must have a
resolution of 3 [mu]m or less. The manner in which the resolution
criterion is met will depend on the type of direct integrity test used.
For example, a pressure decay test can meet the resolution criterion by
applying a net test pressure great enough to overcome the bubble point
of a 3 [mu]m hole. A direct integrity test that uses a particulate or
molecular marker can meet the resolution criterion by applying a marker
of 3 [mu]m or smaller.
Sensitivity is defined as the maximum log removal value that can be
reliably verified by the direct integrity test (LRVDIT). The
sensitivity of the direct integrity test applied to meet the
requirements of this proposed rule must be equal to or greater than the
removal credit awarded to the membrane filtration process. The manner
in which LRVDIT is determined will depend on the type of
direct integrity test used. Direct integrity tests that use an applied
pressure or vacuum typically measure the rate of pressure/vacuum decay
or the flow of air through an integrity breach. The response from this
type of integrity test can be related to the flow of water through an
integrity breach (Qbreach) during normal operation, using
procedures such as those described in the Membrane Filtration Guidance
Manual (USEPA 2003e). Once Qbreach has been determined, a
simple dilution model is used to calculate LRVDIT for the
specific integrity test application, as shown by the following
equation:

LRVDIT = LOG10(Qp/(VCF x
Qbreach))

where LRVDIT = maximum log removal value that can be
verified by a direct integrity test; Qp = total design
filtrate flow from the membrane unit; Qbreach = flow of
water from an integrity breach associated with the smallest integrity
test response that can be reliably measured; and VCF = volumetric
concentration factor.
The volumetric concentration factor is the ratio of the suspended
solids concentration on the high pressure side of the membrane relative
to the feed water, and is defined by the following equation:

VCF = Cm/Cf

where Cm is the concentration of particulate matter on the
high pressure

[[Page 47704]]

side of the membrane that remains in suspension; and Cf is
the concentration of suspended particulate matter in the feed water.
The magnitude of the concentration factor depends on the mode of system
operation and typically ranges from 1 to 20. The Membrane Filtration
Guidance Manual presents approaches for determining the volumetric
concentration factor for different operating modes (USEPA 2003e).
Sensitivity of direct integrity tests that use a particulate or
molecular marker is determined from the feed and filtrate
concentrations of the marker. The LRVDIT for this type of
direct integrity test is calculated according to the following
equation:

LRVDIT = LOG10(Cf) -
LOG10(Cp)

where LRVDIT = maximum log removal value that can be
verified by a direct integrity test; Cf = the typical feed
concentration of the marker used in the test; and Cp = the
filtrate concentration of the marker from an integral membrane unit.
For this equation to be valid, equivalent units must be used for the
feed and filtrate concentrations. An ideal particulate or molecular
marker would be completely removed by an integral membrane unit.
If the sensitivity of the direct integrity test is such that
LRVDIT is less than LRVC-Test, LRVDIT
establishes the maximum removal credit that a membrane filtration
process is eligible to receive. Conversely, if LRVDIT for a
direct integrity test is greater than LRVC-Test,
LRVC-Test establishes the maximum removal credit.
A control limit is defined as an integrity test response which, if
exceeded, indicates a potential problem with the system and triggers a
response. Under this proposal, a control limit for a direct integrity
test must be established that is indicative of an integral membrane
unit capable of meeting the Cryptosporidium removal credit awarded by
the State. If the control limit for the direct integrity test is
exceeded, the membrane unit must be taken off-line for diagnostic
testing and repair. The membrane unit could only be returned to service
after the repair has been completed and confirmed through the
application of a direct integrity test.
The frequency of direct integrity testing specifies how often the
test is performed over an established time interval. Most direct
integrity tests available at the time of this proposal are applied
periodically and must be conducted on each membrane unit at a frequency
of not less than once every 24 hours while the unit is in operation. If
continuous direct integrity test methods become available that also
meet the sensitivity and resolution criteria described earlier, they
may be used in lieu of periodic testing.
EPA is proposing that at a minimum, a monthly report must be
submitted to the State summarizing all direct integrity test results
above the control limit associated with the Cryptosporidium removal
credit awarded to the process and the corrective action that was taken
in each case.
Continuous Indirect Integrity Monitoring
The majority of currently available direct integrity test methods
are applied periodically since the membrane unit must be taken out of
service to conduct the test. In order to provide some measure of
process performance between direct integrity testing events, continuous
indirect integrity monitoring is required. Indirect integrity
monitoring is defined as monitoring some aspect of filtrate water
quality that is indicative of the removal of particulate matter. If a
continuous direct integrity test is implemented that meets the
resolution and sensitivity criteria described previously, continuous
indirect integrity monitoring is not required. Continuous indirect
integrity monitoring must be conducted according to the following
criteria:
[sbull] Unless the State approves an alternative parameter,
continuous indirect integrity monitoring must include continuous
filtrate turbidity monitoring.
[sbull] Continuous monitoring is defined as monitoring conducted at
a frequency of no less than once every 15 minutes.
[sbull] Continuous monitoring must be separately conducted on each
membrane unit.
[sbull] If indirect integrity monitoring includes turbidity and if
the filtrate turbidity readings are above 0.15 NTU for a period greater
than 15 minutes (i.e., two consecutive 15-minute readings above 0.15
NTU), direct integrity testing must be performed on the associated
membrane units.
[sbull] If indirect integrity monitoring includes a State-approved
alternative parameter and if the alternative parameter exceeds a State-
approved control limit for a period greater than 15 minutes, direct
integrity testing must be performed on the associated membrane units.
[sbull] EPA is proposing that at a minimum, a monthly report must
be submitted to the primacy agency summarizing all indirect integrity
monitoring results triggering direct integrity testing and the
corrective action that was taken in each case.
b. How was this proposal developed? The Stage 2 M-DBP Agreement in
Principle recommends that EPA develop criteria to award Cryptosporidium
removal credit to membrane filtration processes. Today's proposal and
the supporting guidance are consistent with the Agreement.
A number of studies have been conducted which have demonstrated the
ability of membrane filtration processes to remove pathogens, including
Cryptosporidium, to below detection levels. A literature review
summarizing the results of several comprehensive studies was conducted
by EPA and is presented in Low-Pressure Membrane Filtration for
Pathogen Removal: Application, Implementation, and Regulatory Issues
(USEPA 2001h). Many of these studies used Cryptosporidium seeding to
demonstrate removal efficiencies as high as 7 log. The collective
results from these studies demonstrate that an integral membrane
module, i.e., a membrane module without any leaks or defects, with an
exclusion characteristic smaller than Cryptosporidium, is capable of
removing this pathogen to below detection in the filtrate, independent
of the feed concentration.
Some filtration devices have used membrane media in a cartridge
filter configuration; however, few data are available documenting their
ability to meet the requirements for membrane filtration described in
section IV.C.11.a of this preamble. However, in one study reported by
Dwyer et al. (2001), a membrane cartridge filter demonstrated
Cryptosporidium removal efficiencies in excess of 6 log. This study
illustrates the potentially high removal capabilities of membrane
filtration media configured into a cartridge filtration device, thus
providing a basis for awarding removal credits to these devices under
the membrane filtration provision of the rule, assuming that the device
meets the definition of a membrane filtration process as well as the
direct integrity test requirements.
Today's proposal requires challenge testing of membrane filtration
processes used to remove Cryptosporidium. As noted in section III.D,
EPA believes this is necessary due to the proprietary nature of these
systems and the lack of any uniform criteria for establishing the
exclusion characteristic of a membrane. Challenge testing addresses the
lack of a standard approach for characterizing membranes by requiring
direct verification of removal efficiency. The proposed challenge
testing is product-specific and not site-specific since the

[[Page 47705]]

intent of this testing is to demonstrate the removal capabilities of
the membrane product rather than evaluate the feasibility of
implementing membrane treatment at a specific plant.
Testing can be conducted using a full-scale module or a smaller
module if the results from the small-scale module test can be related
to full-scale module performance. Most challenge studies presented in
the literature have used full-scale modules, which provide results that
can be directly related to full-scale performance. However, use of
smaller modules is considered feasible in the evaluation of removal
efficiency, and a protocol for challenge testing using small-scale
modules has been proposed (NSF, 2002a). Since the removal efficiency of
an integral membrane is a direct function of the membrane material, it
may be possible to use a small-scale module containing the same
membrane fibers or sheets used in full-scale modules for this
evaluation. However, it will be necessary to relate the results of the
small-scale module test to the nondestructive performance test quality
control release value that will be used to validate full-scale
production modules.
Challenge testing with either Cryptosporidium oocysts or a
surrogate is permitted. Challenge testing with Cryptosporidium clearly
provides direct verification of removal efficiency for this pathogen;
however, several studies have demonstrated that surrogates can provide
an accurate or conservative measure of Cryptosporidium removal
efficiency. Since removal of particulate matter larger than 1 [mu]m by
a membrane filtration process occurs primarily via a size exclusion
mechanism, the shape and size distribution of the surrogate must be
selected such that the surrogate is not removed to a greater extent
than the target organism. Surrogates that have been successfully used
in challenge studies include polystyrene microspheres and bacterial
endospores. The bacterial endospore, Bacillus subtilis, has been used
as a surrogate for Cryptosporidium oocysts during challenge studies
evaluating pathogen removal by physical treatment processes, including
membrane filtration (Rice et al. 1996, Fox et al. 1998, Trimboli et al.
1999, Owen et al, 1999). Studies evaluating cartridge filters have
demonstrated that polystyrene microspheres can provide an accurate or
conservative measure of removal efficiency (Long, 1983, Li et al.
1997). Furthermore, the National Sanitation Foundation (NSF)
Environmental Technology Verification (ETV) protocol for verification
testing for physical removal of microbiological and particulate
contaminants specifies the use of polymeric microspheres of a known
size distribution (NSF 2002b). Guidance on selection of an appropriate
surrogate for establishing a removal efficiency for Cryptosporidium
during challenge testing is presented in the Membrane Filtration
Guidance Manual (USEPA 2003e).
The design of the proposed challenge studies is similar to the
design of the seeding studies described in the literature cited
earlier. Seeding studies are used to challenge the membrane module with
pathogen levels orders of magnitude higher than those encountered in
natural waters. However, elevated feed concentrations can lead to
artificially high estimates of removal efficiency. To address this
issue, the feed concentration applied to the membrane during challenge
studies is capped at a level that will allow the demonstration of up to
6.5 log removal efficiency if the challenge particulate is removed to
the detection level.
Because challenge testing with Cryptosporidium or a surrogate is
not conducted on every membrane module, it is necessary to establish
criteria for a non-destructive performance test that can be applied to
all production membrane modules. Results from a non-destructive test,
such as a bubble point test, that are correlated with the results of
challenge testing can be used to establish a quality control release
value (QCRV) that is indicative of the ability of a membrane filtration
process to remove Cryptosporidium. The non-destructive test and QCRV
can be used to verify the Cryptosporidium removal capability of modules
that are not challenge tested. Most membrane manufacturers have already
adapted some form of non-destructive testing for product quality
control purposes and have established a quality control release value
that is indicative of an acceptable product. It may be possible to
apply these existing practices for the purpose of verifying the
capability of a membrane filtration process to remove Cryptosporidium.
Challenge testing provides a means of demonstrating the removal
efficiency of an integral membrane module; however, defects or leaks in
the membrane or other system components can result in contamination of
the filtrate unless they are identified, isolated, and repaired. In
order to verify continued performance of a membrane system, today's
proposal requires direct integrity testing of membrane filtration
processes used to meet Cryptosporidium treatment requirements. Direct
integrity testing is required because it is a test applied to the
physical membrane module and, thus, a direct evaluation of integrity.
Furthermore, direct integrity methods are the most sensitive integrity
monitoring methods commonly used at the time of this proposal (Adham et
al. 1995).
The most common direct integrity tests apply a pressure or a vacuum
to one side of a fully wetted membrane and monitor either the pressure
decay or the volume of displaced fluid over time. However, the
proprietary nature of these systems makes it impractical to define a
single direct integrity test methodology that is applicable to all
existing and future membrane products. Therefore, performance criteria
have been established for any direct integrity test methodology used to
verify the removal efficiency of a membrane system. These performance
criteria are resolution, sensitivity, and frequency.
As stated previously, the resolution of an integrity test refers to
the smallest leak that contributes to the response from an integrity
test. For example, in a pressure decay integrity test, resolution is
the smallest leak that contributes to pressure loss during the test.
Today's proposal specifies a resolution of 3 [mu]m or less, which is
based on the size of Cryptosporidium oocysts. This requirement ensures
that a leak that could pass a Cryptosporidium oocyst would contribute
to the response from an integrity test.
The sensitivity of an integrity test refers to the maximum log
removal that can be reliably verified by the test. Again using the
pressure decay integrity test as an example, the method sensitivity is
a function of the smallest pressure loss that can be detected over a
membrane unit. Today's proposal limits the log removal credit that a
membrane filtration process is eligible to receive to the maximum log
removal value that can be verified by a direct integrity test.
In order to serve as a useful process monitoring tool for assuring
system integrity, it is necessary to establish a site-specific control
limit for the integrity test that corresponds to the log removal
awarded to the process. A general approach for establishing this
control limit for some integrity test methods is presented in guidance;
however, the utility will need to work with the membrane manufacturer
and State to establish a site-specific control limit appropriate for
the integrity test used and level of credit awarded. Excursions above
this limit indicate a potential integrity breach and would trigger
removal of the suspect unit from service followed by diagnostic testing
and subsequent repair, as necessary.

[[Page 47706]]

Most direct integrity tests available at the time of this proposal
must be applied periodically since it is necessary to take the membrane
unit out of service to conduct the test. Today's proposal establishes
the minimum frequency for performing a direct integrity test at once
per 24 hours. Currently, there is no standard frequency for direct
integrity testing that has been adopted by all States and membrane
treatment facilities. In a recent survey, the required frequency of
integrity testing was found to vary from once every four hours to once
per week; however, the most common frequency for conducting a direct
integrity test was once every 24 hours (USEPA 2001h). Specifically, 10
out of 14 States that require periodic direct integrity testing specify
a frequency of once every 24 hours. Furthermore, many membrane
manufacturers of systems with automated integrity test systems set up
the membrane units to automatically perform a direct integrity test
once per 24 hours. EPA has concluded that the 24 hour direct integrity
test frequency ensures that removal efficiency is verified on a routine
basis without resulting in excessive system downtime.
Since most direct integrity tests are applied periodically, it is
necessary to implement some level of continuous monitoring to assess
process performance between direct integrity test events. In the
absence of a continuous direct integrity test, continuous indirect
integrity monitoring is required. Although it has been shown that
commonly used indirect integrity monitoring methods lack the
sensitivity to detect small integrity breaches that are of concern
(Adham et al. 1995), they can detect large breaches and provide some
assurance that a major failure has not occurred between direct
integrity test events. Turbidity monitoring is proposed as the method
of indirect integrity monitoring unless the State approves an alternate
approach. Available data indicate that an integral membrane filtration
process can consistently produce water with a turbidity less than 0.10
NTU, regardless of the feedwater quality. Consequently, EPA is
proposing that exceedance of a filtrate turbidity value of 0.15 NTU
triggers direct integrity testing to verify and isolate the integrity
breach.
c. Request for comment. EPA requests comment on the following
issues:
[sbull] EPA is proposing to include membrane cartridge filters that
can be direct integrity tested under the definition of a membrane
filtration process since one of the key differences between membrane
filtration processes and bag and cartridge filters, within the context
of this regulation, is the applicability of direct integrity test
methods to the filtration process. EPA requests comment on the
inclusion of membrane cartridge filters that can be direct integrity
tested under the definition of a membrane filtration process in this
rule.
[sbull] The applicability of the proposed Cryptosporidium removal
credits and performance criteria to Giardia lamblia.
[sbull] Appropriate surrogates, or the characteristics of
appropriate surrogates, for use in challenge testing. EPA requests data
or information demonstrating the correlation between removal of a
proposed surrogate and removal of Cryptosporidium oocysts.
[sbull] The use of a non-destructive performance test and
associated quality control release values for demonstrating the
Cryptosporidium removal capability of membrane modules that are not
directly challenge tested.
[sbull] The appropriateness of the minimum direct integrity test
frequency of once per 24 hours.
[sbull] The proposed minimum reporting frequency for direct
integrity testing results above the control limit and indirect
integrity monitoring results that trigger direct integrity monitoring.
12. Bag and Cartridge Filtration
a. What is EPA proposing today? EPA is proposing criteria for
awarding Cryptosporidium removal credit of 1 log for bag filtration
processes and 2 log for cartridge filtration processes. To receive
removal credit the process must: (1) Meet the basic definition of a bag
or cartridge filter and (2) have removal efficiency established through
challenge testing.
Definition of a Bag or Cartridge Filter
For the purpose of this rule, bag and cartridge filters are defined
as pressure driven separation processes that remove particulate matter
larger than 1 [mu]m using an engineered porous filtration media through
either surface or depth filtration.
The distinction between bag filters and cartridge filters is based
on the type of filtration media used and the manner in which the
devices are constructed. Bag filters are typically constructed of a
non-rigid, fabric filtration media housed in a pressure vessel in which
the direction of flow is from the inside of the bag to outside.
Cartridge filters are typically constructed as rigid or semi-rigid,
self-supporting filter elements housed in pressure vessels in which
flow is from the outside of the cartridge to the inside.
Although all filters classified as cartridge filters share
similarities with respect to their construction, there are significant
differences among the various commercial cartridge filtration devices.
From a public health perspective, an important distinction among these
filters is the ability to directly test the integrity of the filtration
system in order to verify that there are no leaks that could result in
contamination of the filtrate. Any membrane cartridge filtration device
that can be direct integrity tested according to the criteria specified
in section IV.C.11.a is eligible for removal credit as a membrane,
subject to the criteria specified in that section. Section IV.C.12
applies to all bag filters, as well as to cartridge filters which
cannot be direct integrity tested.
Challenge Testing
In order to receive 1 log removal credit, a bag filter must have a
demonstrated removal efficiency of 2 log or greater for
Cryptosporidium. Similarly, to receive 2 log removal credit, a
cartridge filter must have a demonstrated removal efficiency of 3 log
or greater for Cryptosporidium. The 1 log factor of safety is applied
to the removal credit awarded to these filtration devices based on two
primary considerations. First, the removal efficiency of some bag and
cartridge filters has been observed to vary by more than 1 log over the
course of operation (Li et al. 1997, NSF 2001a, NSF 2001b). Second, bag
and cartridge filters are not routinely direct integrity tested during
operation in the field; hence, there is no means of verifying the
removal efficiency of filtration units during routine use. Based on
these considerations, a conservative approach to awarding removal
credit based on challenge test results is warranted.
Removal efficiency must be demonstrated through a challenge test
conducted on the bag or cartridge filter proposed for use in full-scale
drinking water treatment facilities for removal of Cryptosporidium.
Challenge testing is required for specific products and is not intended
to be site specific. At the discretion of the State, data from
challenge studies conducted prior to promulgation of this regulation
may be considered in lieu of additional testing. However, the prior
testing must have been conducted in a manner that demonstrates a
removal efficiency for Cryptosporidium commensurate with the treatment
credit awarded to the process. Guidance on conducting challenge studies
to demonstrate the Cryptosporidium removal efficiency of filtration
units is presented in the Membrane Filtration Guidance Manual (USEPA
2003e). Challenge testing must

[[Page 47707]]

be conducted according to the following criteria:
[sbull] Challenge testing must be conducted on a full-scale filter
element identical in material and construction to the filter elements
proposed for use in full-scale treatment facilities.
[sbull] Challenge testing must be conducted using Cryptosporidium
oocysts or a surrogate which is removed no more efficiently than
Cryptosporidium oocysts. The organism or surrogate used during
challenge testing is referred to as the challenge particulate. The
concentration of the challenge particulate must be determined using a
method capable of discretely quantifying the specific organism or
surrogate used in the test, i.e., gross water quality measurements such
as turbidity cannot be used.
[sbull] The maximum allowable feed water concentration used during
a challenge test is based on the detection limit of the challenge
particulate in the filtrate and calculated using one of the following
equations.
For bag filters:

Maximum Feed Concentration = 3.16 x 10³ x (Filtrate
Detection Limit)
For cartridge filters:

Maximum Feed Concentration = 3.16 x 10⁴ x (Filtrate
Detection Limit)

This will allow the demonstration of up to 3.5 log removal for bag
filters and 4.5 log removal for cartridge filters during challenge
testing if the challenge particulate is removed to the detection limit.
[sbull] Challenge testing must be conducted at the maximum design
flow rate specified by the manufacturer.
[sbull] Each filter must be tested for a duration sufficient to
reach 100% of the terminal pressure drop, a parameter specified by the
manufacturer which establishes the end of the useful life of the
filter. In order to achieve terminal pressure drop during the test, it
will be necessary to add particulate matter to the test solution, such
as fine carbon test dust or bentonite clay particles.
[sbull] Each filter must be challenged with the challenge
particulate during three periods over the filtration cycle: within 2
hours of start-up after a new bag or cartridge filter has been
installed, when the pressure drop is between 45 and 55% of the terminal
pressure drop, and at the end of the run after the pressure drop has
reached 100% of the terminal pressure drop.
[sbull] Removal efficiency of a bag or cartridge filtration process
is determined from the results of the challenge test, and expressed in
terms of log removal values as defined by the following equation:

LRV = LOG10(Cf)-LOG10(Cp)

Table IV-18.--Results From Studies of Cryptosporidium or Surrogate Removal by Bag and Cartridge Filters
----------------------------------------------------------------------------------------------------------------
Process Log removal Organism/surrogate Reference
----------------------------------------------------------------------------------------------------------------
Bag and cartridge filtration in 1.1 to 2.1............. 3 to 6 [mu]m spheres... NSF 2001a.
series.
Cartridge filtration................. 3.5 (average).......... Cryptosporidium........ Enriquez et al. 1999.
Cartridge filtration................. 3.3 (average).......... Cryptosporidium........ Roessler, 1998.
Cartridge filtration................. 1.1 to 3.3............. Cryptosporidium........ Schaub et al. 1993.
Cartridge filtration................. 0.5 to 3.6............. 5.7 [mu]m spheres...... Long, 1983.
Cartridge filtration................. 2.3 to 2.8............. Cryptosporidium........ Ciardelli, 1996a.
Cartridge filtration................. 2.7 to 3.7............. Cryptosporidium........ Ciardelli, 1996b.
Prefilter and bag filter in series... 1.9 to 3.2............. 3.7 [mu]m spheres...... NSF 2001b.
Bag filtration....................... [sim]3.0............... Cryptosporidium........ Cornwell and
LeChevallier, 2002.
Bag filtration....................... 0.5 to 3.6............. Cryptosporidium........ Li et al. 1997.
Bag filtration....................... 0.5 to 2.0............. 4.5 [mu]m spheres...... Goodrich et al. 1995.
----------------------------------------------------------------------------------------------------------------

These data demonstrate highly variable removal performance for
these processes, ranging from 0.5 log to 3.6 log for both bag and
cartridge filtration. Results of these studies also show no correlation
between the pore size rating established by the manufacturer and the
removal efficiency of a filtration device. In a study evaluating two
cartridge filters, both with a pore size rating of 3 [mu]m, a 2 log
difference in Cryptosporidium oocyst removal was observed between the
two filters (Schaub et al. 1993). Another study evaluated seventeen
cartridge filters with a range of pore size ratings from 1 [mu]m to 10
[mu]m and found no correlation with removal efficiency (Long, 1983). Li
et al. (1997) evaluated three bag filters with similar pore size
ratings and observed a 3 log difference in

[[Page 47708]]

Cryptosporidium oocyst removal among them. These results indicate that
bag and cartridge filters may be capable of achieving removal of
oocysts in excess of 3 log; however, performance can vary significantly
among products and there appears to be no correlation between pore size
rating and removal efficiency.
Based on available data, specific design criteria that correlate to
removal efficiency cannot be derived for bag and cartridge filters.
Furthermore, the removal efficiency of these proprietary devices can be
impacted by product variability, increasing pressure drop over the
filtration cycle, flow rate, and other operating conditions. The data
in Table IV-18 were generated from studies performed under a variety of
operating conditions, many of which could not be considered
conservative (or worst-case) operation. These considerations lead to
the proposed challenge testing requirements which are intended to
establish a product-specific removal efficiency.
The proposed challenge testing is product-specific and not site-
specific since the intent of this testing is to demonstrate the removal
capabilities of the filtration device rather than evaluate the
feasibility of implementing the technology at a specific plant.
Challenge testing must be conducted using full-scale filter elements in
order to evaluate the performance of the entire unit, including the
filtration media, seals, filter housing and other components integral
to the filtration system. This will improve the applicability of
challenge test results to full-scale performance. Multiple filters of
the same type can be tested to provide a better statistical basis for
estimating removal efficiency.
Either Cryptosporidium oocysts or a suitable surrogate could be
used as the challenge particulate during the test. Challenge testing
with Cryptosporidium provides direct verification of removal
efficiency; however, some studies have demonstrated that surrogates,
such as polystyrene microspheres, can provide an accurate or
conservative measure of removal efficiency (Long 1983, Li et al. 1997).
Furthermore, the National Sanitation Foundation (NSF) Environmental
Technology Verification (ETV) protocol for verification testing for
physical removal of microbiological and particulate contaminants
specifies the use of polymeric microspheres of a known size
distribution (NSF 2002b). Guidance on selection of an appropriate
surrogate for establishing a removal efficiency for Cryptosporidium
during challenge testing is presented in the Membrane Filtration
Guidance Manual (USEPA 2003e).
In order to demonstrate a removal efficiency of at least 2 or 3 log
for bag or cartridge filters, respectively, it will likely be necessary
to seed the challenge particulate into the test solution. A criticism
of published studies that use this approach is that the seeded levels
are orders of magnitude higher than those encountered in natural waters
and this could potentially lead to artificially high estimates of
removal efficiency. To address this issue, the feed concentration
applied to the filter during challenge studies is capped at a level
that will allow the demonstration of a removal efficiency up to 4.5 log
for cartridge filters and 3.5 log for bag filters if the challenge
particulate is removed to the detection level.
The removal efficiency of some bag and cartridge filtration devices
has been shown to decrease over the course of a filtration cycle due to
the accumulation of solids and resulting increase in pressure drop. As
an example, Li et al. (1997) observed that the removal of 4.5 [mu]m
microspheres by a bag filter decreased from 3.4 log to 1.3 log over the
course of a filtration cycle. Studies evaluating bag and cartridge
filtration under the NSF ETV program have also shown a degradation in
removal efficiency over the course of the filtration cycle (NSF 2001a
and 2001b). In order to evaluate this potential variability, the
challenge studies are designed to assess removal efficiency during
three periods of a filtration cycle: within two hours of startup
following installation of a new filter, between 45% and 55% of terminal
pressure drop, and at the end of the run after 100% of terminal
pressure drop is realized.
Although challenge testing can provide an estimate of removal
efficiency for a bag or cartridge filtration process, it is not
feasible to conduct a challenge test on every production filter. This,
coupled with variability within a product line, could result in some
production filters that do not meet the removal efficiency demonstrated
during challenge testing. For membrane filtration processes, this
problem is addressed through the use of a quality control release value
established for a non-destructive test, such as a bubble point test or
pressure hold test, that is correlated to removal efficiency. Since the
non-destructive test can be applied to all production membrane modules,
this provides a feasible means of verifying the performance of every
membrane module used by a PWS. However, the non-destructive tests
applied to membrane filtration processes cannot be applied to most bag
and cartridge filtration devices, and EPA is not aware of an
alternative non-destructive test that can be used with these devices.
Typical process monitoring for bag and cartridge filtration systems
includes turbidity and pressure drop to determine when filters must be
replaced. However, the applicability of either of these process
monitoring parameters as tools for verifying removal of Cryptosporidium
has not been demonstrated. Only a few bag or cartridge filtration
studies have attempted to correlate turbidity removal with removal of
Cryptosporidium oocysts or surrogates. Li et al. (1997) found that the
removal efficiency for turbidity was consistently lower than removal
efficiency for oocysts or microspheres for the three bag filters
evaluated. Furthermore, none of the filters was capable of consistently
producing a filtered water turbidity below 0.3 NTU for the waters
evaluated. The contribution to turbidity from particles much smaller
than Cryptosporidium oocysts, and much smaller than the mesh size of
the filter, make it difficult to correlate removal of turbidity with
removal of Cryptosporidium. Consequently, EPA is proposing a 1 log
factor of safety to be applied to challenge test results in awarding
treatment credit to bag and cartridge filters, and is not proposing
integrity monitoring requirements for these devices.
c. Request for comment. EPA requests comment on the following
issues concerning bag and cartridge filters:
[sbull] The performance of bag and cartridge filters in removing
Cryptosporidium through all differential pressure ranges in a filter
run--EPA requests laboratory and field data, along with associated
quality assurance and quality control information, that will support a
determination of the appropriate level of Cryptosporidium removal
credit to award to these technologies.
[sbull] The performance of bag and cartridge filters in removing
Cryptosporidium when used in series with other bag or cartridge
filters--EPA requests laboratory and field data, along with associated
quality assurance and quality control information, that will support a
determination of the appropriate level of Cryptosporidium removal
credit to award to these technologies when used in series.
[sbull] Appropriate surrogates, or the characteristics of
appropriate surrogates, for use in challenge testing bag and cartridge
filters--EPA requests data or information demonstrating the correlation
between removal of a proposed surrogate and removal of Cryptosporidium
oocysts.

[[Page 47709]]

[sbull] The availability of non-destructive tests that can be
applied to bag and cartridge filters to verify the removal efficiency
of production filters that are not directly challenge tested--EPA
requests data or information demonstrating the correlation between a
proposed non-destructive test and the removal of Cryptosporidium
oocysts.
[sbull] The applicability of pressure drop monitoring, filtrate
turbidity monitoring, or other process monitoring and process control
procedures to verify the integrity of bag and cartridge filters--EPA
requests data or information demonstrating the correlation between a
proposed process monitoring tool and the removal of Cryptosporidium
oocysts.
[sbull] The applicability of bag and cartridge filters to different
source water types and treatment scenarios.
[sbull] The applicability of the proposed Cryptosporidium removal
credits and testing criteria to Giardia lamblia.
[sbull] The use of a 1 log factor of safety for awarding credit to
bag and cartridge filters--EPA requests comment on whether this is an
appropriate factor of safety to account for the inability to conduct
integrity monitoring of these devices, as well as the variability in
removal efficiency observed over the course of a filtration cycle for
some filtration devices. This inability creates uncertainty regarding
both changes in the performance of a given filter during use and
variability in performance among filters in a given product line. If
the 1 log factor of safety is higher than necessary to account for
these factors, should the Agency establish a lower value, such as a 0.5
log factor of safety?
13. Secondary Filtration
a. What is EPA proposing today? Today's proposal allows systems
using a second filtration stage to receive an additional 0.5 log
Cryptosporidium removal credit. To be eligible for this credit, the
secondary filtration must consist of rapid sand, dual media, granular
activated carbon (GAC), or other fine grain media in a separate stage
following rapid sand or dual media filtration. A cap, such as GAC, on a
single stage of filtration will not qualify for this credit. In
addition, the first stage of filtration must be preceded by a
coagulation step, and both stages must treat 100% of the flow.
b. How was this proposal developed? Although not addressed in the
Agreement in Principle, EPA has determined that secondary filtration
meeting the criteria described in this section will achieve additional
removal of Cryptosporidium oocysts. Consequently, additional removal
credit may be appropriate. As reported in section III.D, many studies
have shown that rapid sand filtration preceded by coagulation can
achieve significant removal of Cryptosporidium (Patania et al. 1995,
Nieminski and Ongerth 1995, Ongerth and Pecoraro 1995, LeChevallier and
Norton 1992, LeChevallier et al. 1991, Dugan et al. 2001, Nieminski and
Bellamy 2000, McTigue et al. 1998, Patania et al. 1999, Huck et al.
2000, Emelko et al. 2000). While these studies evaluated only a single
stage of filtration, the same mechanisms of removal are expected to
occur in a second stage of granular media filtration.
EPA received data from the City of Cincinnati, OH, on the removal
of aerobic spores through a conventional treatment facility that
employs GAC contactors for DBP, taste, and odor control after rapid
sand filtration. As described previously, a number of studies (Dugan et
al. 2001, Emelko et al. 1999 and 2000, Yates et al. 1998, Mazounie et
al. 2000) have demonstrated that aerobic spores are a conservative
indicator of Cryptosporidium removal by granular media filtration when
preceded by coagulation.
During the period of 1999 and 2000, the mean values of reported
spore concentrations in the influent and effluent of the Cincinnati GAC
contactors were 35.7 and 6.4 cfu/100 mL, respectively, indicating an
average removal of 0.75 log across the contactors. Approximately 16% of
the GAC filtered water results were below detection limit (1 cfu/100
mL) so the actual log spore removal may have been greater than
indicated by these results.
In summary, studies in the cited literature demonstrate that a fine
granular media filter preceded by coagulation can achieve high levels
of Cryptosporidium removal. Data on increased removal resulting from a
second stage of filtration are limited, and there is uncertainty
regarding how effective a second stage of filtration will be in
reducing levels of microbial pathogens that are not removed by the
first stage of filtration. However, EPA has concluded that a secondary
filtration process can achieve 0.5 log or greater removal of
Cryptosporidium based on (1) the theoretical consideration that the
same mechanisms of pathogen removal will be operative in both a primary
and secondary filtration stage, and (2) data from the City of
Cincinnati showing aerobic spore removal in GAC contactors following
rapid sand filtration. Therefore, EPA believes it is appropriate to
propose 0.5 log additional Cryptosporidium treatment credit for systems
using secondary filtration which meets the criteria of this section.
c. Request for comment. The Agency requests comment on awarding a
0.5 log Cryptosporidium removal credit for systems using secondary
filtration, including the design and operational criteria required to
receive the log removal credit. EPA specifically requests comment on
the following issues:
[sbull] Should there be a minimum required depth for the secondary
filter (e.g., 24 inches) in order for the system to receive credit?
[sbull] Should systems be eligible to receive additional
Cryptosporidium treatment credit within the microbial toolbox for both
a second clarification stage (e.g., secondary filtration, second stage
sedimentation) and lower finished water turbidity, given that
additional particle removal achieved by the second clarification stage
will reduce finished water turbidity?
14. Ozone and Chlorine Dioxide
a. What is EPA proposing today? Similar to the methodology used for
estimating log inactivation of Giardia lamblia by various chemical
disinfectants in 40 CFR 141.74, EPA is proposing the CT concept for
estimating log inactivation of Cryptosporidium by chlorine dioxide or
ozone. In today's proposal, systems must determine the total
inactivation of Cryptosporidium each day the system is in operation,
based on the CT values in Table IV-19 for ozone and Table IV-20 for
chlorine dioxide. The parameters necessary to determine the total
inactivation of Cryptosporidium must be monitored as stated in 40 CFR
141.74(b)(3)(i), (iii), and (iv), which is as follows:
[sbull] The temperature of the disinfected water must be measured
at least once per day at each residual disinfectant concentration
sampling point.
[sbull] The disinfectant contact time(s) (``T'') must be determined
for each day during peak hourly flow.
[sbull] The residual disinfectant concentration(s) (``C'') of the
water before or at the first customer must be measured each day during
peak hourly flow.
Systems may have several disinfection segments (the segment is
defined as a treatment unit process with a measurable disinfectant
residual level and a liquid volume) in sequence along the treatment
train. In determining the total log inactivation, the system may
calculate the log inactivation for each disinfection segment and use
the sum of the log inactivation estimates of Cryptosporidium achieved
through the

[[Page 47710]]

plant. The Toolbox Guidance Manual, available in draft with today's
proposal, provides guidance on methodologies for determining CT values
and estimating log inactivation for different disinfection reactor
designs and operations.

Table IV-19.--CT Values for Cryptosporidium Inactivation by Ozone
--------------------------------------------------------------------------------------------------------------------------------------------------------
Water Temperature, [deg]C \1\
Log credit -----------------------------------------------------------------------------------------
<=0.5 1 2 3 5 7 10 15 20 25
--------------------------------------------------------------------------------------------------------------------------------------------------------
0.5........................................................... 12 12 10 9.5 7.9 6.5 4.9 3.1 2.0 1.2
1.0........................................................... 24 23 21 19 16 13 9.9 6.2 3.9 2.5
1.5........................................................... 36 35 31 29 24 20 15 9.3 5.9 3.7
2.0........................................................... 48 46 42 38 32 26 20 12 7.8 4.9
2.5........................................................... 60 58 52 48 40 33 25 16 9.8 6.2
3.0........................................................... 72 69 63 57 47 39 30 19 12 7.4
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CT values between the indicated temperatures may be determined by interpolation.

Table IV-20.--CT Values for Cryptosporidium Inactivation by Chlorine Dioxide
--------------------------------------------------------------------------------------------------------------------------------------------------------
Water Temperature, [deg]C \1\
Log credit -----------------------------------------------------------------------------------------
<=0.5 1 2 3 5 7 10 15 20 25
--------------------------------------------------------------------------------------------------------------------------------------------------------
0.5........................................................... 319 305 279 256 214 180 138 89 58 38
1.0........................................................... 637 610 558 511 429 360 277 179 116 75
1.5........................................................... 956 915 838 767 643 539 415 268 174 113
2.0........................................................... 1275 1220 1117 1023 858 719 553 357 232 150
2.5........................................................... 1594 1525 1396 1278 1072 899 691 447 289 188
3.0........................................................... 1912 1830 1675 1534 1286 1079 830 536 347 226
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CT values between the indicated temperatures may be determined by interpolation.

The system may demonstrate to the State, through the use of a
State-approved protocol for on-site disinfection challenge studies or
other information satisfactory to the State, that CT values other than
those specified in Tables IV-19 or IV-20 are adequate to demonstrate
that the system is achieving the required log inactivation of
Cryptosporidium. Protocols for making such demonstrations are available
in the Toolbox Guidance Manual.
b. How was this proposal developed? EPA relied in part on analyses
by Clark et al. (2002a and 2002b) to develop the CT values for ozone
and chlorine dioxide inactivation of Cryptosporidium in today's
proposal. Clark et al. (2002a) used data from studies of ozone
inactivation of Cryptosporidium in laboratory water to develop
predictive equations for estimating inactivation (Rennecker et al.
1999, Li et al. 2001) and data from studies in natural water to
validate the equations (Owens et al. 2000, Oppenheimer et al. 2000).
For chlorine dioxide, Clark et al. (2002b) employed data from Li et al.
(2001) to develop equations for predicting inactivation, and used data
from Owens et al. (1999) and Ruffell et al. (2000) to validate the
equations.
Another step in developing the CT values for Cryptosporidium
inactivation in today's proposal involved consideration of the
appropriate confidence bound to apply when analyzing the inactivation
data. A confidence bound represents a safety margin that accounts for
variability and uncertainty in the data that underlie the analysis.
Confidence bounds are intended to provide a high likelihood that
systems operating at a given CT value will achieve at least the
corresponding log inactivation level in the CT table.
Two types of confidence bounds that are used when assessing
relationships between variables, such as disinfectant dose (CT) and log
inactivation, are confidence in the regression and confidence in the
prediction. Confidence in the regression accounts for uncertainty in
the regression line (e.g., a linear relationship between temperature
and the log of the ratio of CT to log inactivation). Confidence in the
prediction accounts for both uncertainty in the regression line and
variability in experimental observations--it describes the likelihood
of a single future data point falling within a range. Bounds for
confidence in prediction are wider (i.e., more conservative) than those
for confidence in the regression. Depending on the degree of confidence
applied, most points in a data set typically will fall within the
bounds for confidence in the prediction, while a significant fraction
will fall outside the bounds for confidence in the regression.
In developing earlier CT tables, EPA has used bounds for confidence
in the prediction. This was a conservative approach that was taken with
consideration of the limited inactivation data that were available and
that reasonably ensured systems would achieve the required inactivation
level. The November 2001 draft of the LT2ESWTR included CT tables for
Cryptosporidium inactivation by ozone and chlorine dioxide that were
derived using confidence in prediction (USEPA 2001g). However, based on
comments received on those draft tables, along with further analyses
described next, EPA has revised this approach in today's proposal.
The underlying Cryptosporidium inactivation data used to develop
the CT tables exhibit significant variability. This variability is due
to both experimental error and potential true variability in the
inactivation rate. Experimental error is associated with the assays
used to measure loss of infectivity, measurement of the disinfectant
concentration, differences in technique among researchers, and other
factors. True variability in the inactivation rate would be associated
with variability in resistance to the disinfectant between different
populations of oocysts and variability in the effect of water matrix on
the inactivation process.

[[Page 47711]]

In considering the appropriate confidence bounds to use for
developing the CT tables in today's proposal, EPA was primarily
concerned with accounting for uncertainty in the regression and for
true variability in the inactivation rate. Variability associated with
experimental error was a lessor concern, as the purpose of the CT
tables is to ensure a given level of inactivation and not predict the
measured result of an individual experiment.
Because confidence in the prediction accounts for all variability
in the data sets (both true variability and experimental error), it may
provide a higher margin of safety than is necessary. Nevertheless, in
other disinfection applications, the use of confidence in the
prediction may be appropriate, given limited data sets and uncertainty
in the source of the variability. However, the high doses of ozone and
chlorine dioxide that are needed to inactivate Cryptosporidium create
an offsetting concern with the formation of DBPs (e.g., bromate and
chlorite). In consideration of these factors and the statutory
provision for balancing risks among contaminants, EPA attempted to
exclude experimental error from the confidence bound when developing
the CT tables in today's proposal (i.e., used a less conservative
approach than confidence in the prediction).
In order to select confidence bounds reflecting potential true
variability between different oocyst populations (lots) but not
variability due to measurement and experimental imprecision, it was
necessary to estimate the relative contributions of these variance
components. This was done by first separating inactivation data points
into groups having the same Cryptosporidium oocyst lot and experimental
conditions (e.g., water matrix, pH, temperature). Next, the variance
within each group was determined. It was assumed that this within-group
variance could be attributed entirely to experimental error, as neither
of the factors expected to account for true variability in the
inactivation rate (i.e., oocyst lot or water matrix) changed within a
group. Finally, comparing the average within-group variance to the
total variance in a data set provided an indication of the fraction of
total variance that was due to experimental error (see Sivaganesan 2003
and Messner 2003 for details).
In carrying out this analysis on the Li et al. (2001) and Rennecker
et al. (1999) data sets for ozone inactivation of Cryptosporidium, EPA
estimated that 87.5% of the total variance could be attributed to
experimental error (Sivaganesan 2003). A similar analysis done by Najm
et al. (2002) on the Oppenheimer et al. (2000) data set for ozone
produced an estimate of 89% of the total variance due to experimental
error. For chlorine dioxide inactivation of Cryptosporidium, EPA
estimated that 62% of the total variance in the Li et al. (2001) and
Ruffle et al. (1999) data sets could be attributed to experimental
error (Messner 2003). The different fractions attributed to
experimental error between the chlorine dioxide and ozone data sets
presumably relates to the use of different experimental techniques
(e.g., infectivity assays).
EPA employed estimates of the fraction of variance not attributable
to experimental error (12.5% for ozone and 38% for chlorine dioxide) in
a modified form of the equation used to calculate a bound for
confidence in prediction (Messner 2003). These were applied to the
regression equations developed by Clark et al. (2002a and 2002b) in
order to estimate CT values for an upper 90% confidence bound
(Sivaganesan 2003, Messner 2003). These are the CT values shown in
Tables IV-19 and IV-20 for ozone and chlorine dioxide, respectively.
Since the available data are not sufficient to support the CT
calculation for an inactivation level greater than 3 log, the use of
Tables IV-19 and IV-20 is limited to inactivation less than or equal to
3 log. In addition, the temperature limitation for these tables is 1 to
25 [deg]C. If the water temperature is higher than 25 [deg]C,
temperature should be set to 25 [deg]C for the log inactivation
calculation.
EPA recognizes that inactivation rates may be sensitive to water
quality and operational conditions in the plant. To reflect this
potential, systems are given the option to perform a site specific
inactivation study to determine CT requirements. The State must approve
the protocols or other information used to derive alternative CT
values. However, EPA has provided guidance for systems in making such
demonstrations in the Toolbox Guidance Manual.
During meetings of the Stage 2 M-DBP Advisory Committee, CT values
were used in the model for impact analysis of different regulatory
options (the model Surface Water Analytical Tool (SWAT), as described
in Economic Analysis for the LT2ESWTR, USEPA 2003a). Those preliminary
CT values were based on a subset of the data from the Li et al. (2001)
study with laboratory waters and were adjusted with a factor to match
the mean CT values derived from the Oppenheimer et al. (2000) study
with natural waters. In comparison, the CT values in today's proposal
are higher. However, the current CT values are based on larger data
sets and more comprehensive analyses. Consequently, they provide more
confidence in estimates of Cryptosporidium log inactivation than the
preliminary estimates used in earlier SWAT modeling. EPA has
subsequently re-run analyses for LT2ESWTR impact assessments with the
updated CT values (USEPA 2003a).
c. Request for comments. EPA requests comment on the proposed
approach to awarding credit for inactivation of Cryptosporidium by
chlorine dioxide and ozone, including the following specific issues:
[sbull] Determination of CT and the confidence bounds used for
estimating log inactivation of Cryptosporidium;
[sbull] The ability of systems to apply these CT tables in
consideration of the MCLs for bromate and chlorite; and
[sbull] Any additional data that may be used to confirm or refine
the proposed CT tables.
15. Ultraviolet Light
a. What is EPA proposing today? EPA is proposing criteria for
awarding credit to ultraviolet (UV) disinfection processes for
inactivation of Cryptosporidium, Giardia lamblia, and viruses. The
inactivation credit a system can receive for each target pathogen is
based on the UV dose applied by the system in relation to the UV dose
requirements in this section (see Table IV-21).
To receive UV disinfection credit, a system must demonstrate a UV
dose using the results of a UV reactor validation test and ongoing
monitoring. The reactor validation test establishes the operating
conditions under which a reactor can deliver a required UV dose.
Monitoring is used to demonstrate that the system maintains these
validated operating conditions during routine use.
UV dose (fluence) is defined as the product of the UV intensity
over a surface area (fluence rate) and the exposure time. In practice,
UV reactors deliver a distribution of doses due to variation in light
intensity and flow path as particles pass through the reactor. However,
for the purpose of determining compliance with the dose requirements in
Table IV-21, UV dose must be assigned to a reactor based on the degree
of inactivation of a microorganism achieved during a reactor validation
test. This assigned UV dose is determined through comparing the reactor
validation test results with a known dose-response relationship for the
test microorganism. The State may

[[Page 47712]]

designate an alternative basis for awarding UV disinfection credit.
EPA is developing the UV Disinfection Guidance Manual (USEPA 2003d)
to assist systems and States with implementing UV disinfection,
including validation testing of UV reactors. This guidance is available
in draft in the docket for today's proposal (http://www.epa.gov/
edocket/).
UV Dose Tables
Table IV-21 shows the UV doses that systems must apply to receive
credit for up to 3 log inactivation of Cryptosporidium and Giardia
lamblia and up to 4 log inactivation of viruses. These dose values are
for UV light at a wavelength of 254 nm as delivered by a low pressure
mercury vapor lamp. However, the dose values can be applied to other UV
lamp types (e.g., medium pressure mercury vapor lamps) through reactor
validation testing, such as is described in the draft UV Disinfection
Guidance Manual (USEPA 2003d). In addition, the dose values in Table
IV-21 are intended for post-filter application of UV in filtration
plants and for systems that meet the filtration avoidance criteria in
40 CFR 141.71.
BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TP11AU03.011

BILLING CODE 6560-50-C
Reactor Validation Testing
For a system to receive UV disinfection credit, the UV reactor type
used by the system must undergo validation testing to demonstrate the
operating conditions under which the reactor can deliver the required
UV dose. Unless the State approves an alternative approach, this
testing must involve the following: (1) Full scale testing of a reactor
that conforms uniformly to the UV reactors used by the system and (2)
inactivation of a test microorganism whose dose response
characteristics have been quantified with a low pressure mercury vapor
lamp.
Validation testing must determine a set of operating conditions
that can be monitored by the system to ensure that the required UV dose
is delivered under the range of operating conditions applicable to the
system. At a minimum, these operating conditions must include flow
rate, UV intensity as measured by a UV sensor, and UV lamp status. The
validated operating conditions determined by testing must account for
the following factors: (1) UV absorbance of the water, (2) lamp fouling
and aging, (3) measurement uncertainty of on-line sensors, (4) dose
distributions arising from the velocity profiles through the reactor,
(5) failure of UV lamps or other critical system components, and (6)
inlet and outlet piping or channel configurations of the UV reactor. In
the draft UV Disinfection Guidance Manual (USEPA 2003d), EPA describes
testing protocols for reactor validation that are intended to meet
these criteria.
Reactor Monitoring
Systems must monitor for parameters necessary to demonstrate
compliance with the operating conditions that were validated for the
required UV dose. At a minimum systems must monitor for UV intensity as
measured by a UV sensor, flow rate, and lamp outage. As part of this,
systems must check the calibration of UV sensors and recalibrate in
accordance with a protocol approved by the State.
b. How was this proposal developed? UV disinfection is a physical
process relying on the transference of electromagnetic energy from a
source (lamp) to an organism's cellular material (USEPA 1986). In the
Stage 2 M-DBP Agreement in Principle, the Advisory Committee
recommended that EPA determine the UV doses needed to achieve up to 3
log inactivation of Giardia lamblia and Cryptosporidium and up to 4 log
inactivation of viruses.
The Agreement further recommends that EPA develop standards to
determine if UV systems are acceptable for compliance with drinking
water disinfection requirements, including (1) a validation protocol
for drinking water applications of UV technology and (2) on-site
monitoring requirements to ensure ongoing compliance with UV dose
tables. EPA also agreed to develop a UV guidance manual to facilitate
design and operation of UV installations. Today's proposal and

[[Page 47713]]

accompanying guidance for UV are consistent with the Agreement.
UV Dose Tables
The UV dose values in Table IV-21 are based on meta-analyses of UV
inactivation studies with Cryptosporidium parvum, Giardia lamblia,
Giardia muris, and adenovirus (Qian et al. 2003, USEPA 2003d). Proposed
UV doses for inactivation of viruses are based on the dose-response of
adenovirus because, among viruses that have been studied, it appears to
be the most UV resistant and is a widespread waterborne pathogen
(health effects of adenovirus are described in Embrey 1999).
The data supporting the dose values in Table IV-21 are from bench-
scale studies using low pressure mercury vapor lamps. These data were
chosen because the experimental conditions allow UV dose to be
accurately quantified. Low pressure lamps emit light primarily at a
single wavelength (254 nm) within the germicidal range of 200-300 nm.
However, as noted earlier, these dose tables can be applied to reactors
with other lamp types through reactor challenge testing, as described
in the draft guidance manual. Bench scale studies are preferable for
determining pathogen dose-response characteristics, due to the uniform
dose distribution.
The data sets and statistical evaluation that were used to develop
the UV dose table for Cryptosporidium, Giardia lamblia, and viruses are
described in the draft UV Disinfection Guidance Manual (USEPA 2003d)
and Qian et al. 2003.
Reactor Validation Testing
Today's proposal requires testing of full-scale UV reactors because
of the difficulty in predicting reactor disinfection performance based
on modeled results or on the results of testing at a reduced scale. All
flow-through UV reactors deliver a distribution of doses due to
variation in light intensity within the reactor and the different flow
paths of particles passing through the reactor. Moreover, the reactor
dose distribution varies temporally due to processes like lamp aging
and fouling, changes in UV absorbance of the water, and fluctuations in
flow rate. Consequently, it is more reliable to evaluate reactor
performance through a full scale test under conditions that can be
characterized as ``worst case'' for a given application. Such
conditions include maximum and minimum flow rate and reduced light
intensity within the reactor that accounts for lamp aging, fouling, and
UV absorbance of the water. Protocols for reactor validation testing
are presented in the draft UV guidance manual.
c. Request for comment. The Agency requests comment on whether the
criteria described in this section for awarding treatment credit for UV
disinfection are appropriate, and whether additional criteria, or more
specific criteria, should be included.
16. Individual Filter Performance
a. What is EPA proposing today? EPA is proposing an additional 1.0
log Cryptosporidium treatment credit for systems that achieve
individual filter performance consistent with the goals established for
the Partnership for Safe Water Phase IV in August 2001 (AWWA et al.
2001). Specifically, systems must demonstrate ongoing compliance with
the following turbidity criteria, based on continuous monitoring of
turbidity for each individual filter as required under 40 CFR 141.174
or 141.560, as applicable:

(1) Filtered water turbidity less than 0.1 NTU in at least 95%
of the maximum daily values recorded at each filter in each month,
excluding the 15 minute period following backwashes, and
(2) No individual filter with a measured turbidity level of
greater than 0.3 NTU in two consecutive measurements taken 15
minutes apart.

Note that today's proposal does not include a required peer review
step as a condition for receiving additional credit. Rather, EPA is
proposing to award additional credit to systems that meet the
performance goals of a peer review program (Phase IV). Systems that
receive the 1 log additional treatment credit for individual filter
performance, as described in this section, cannot also receive an
additional 0.5 log additional credit for lower finished water turbidity
as described in section IV.C.8.
b. How was this proposal developed? In the Stage 2 M-DBP Agreement
in Principle, the Advisory Committee recommended a peer review program
as a microbial toolbox component that should receive a 1.0 log
Cryptosporidium treatment credit. The Committee specified Phase IV of
the Partnership for Safe Water (Partnership) as an example of the type
of peer review program where a 1.0 log credit would be appropriate.
The Partnership is a voluntary cooperative program involving EPA,
the Association of Metropolitan Water Agencies (AMWA), the American
Water Works Association (AWWA), the National Association of Water
Companies (NAWC), the Association of State Drinking Water
Administrators (ASDWA), the American Water Works Association Research
Foundation (AWWARF), and surface water utilities throughout the United
States. The intent of the Partnership is to increase protection against
microbial contaminants by optimizing treatment plant performance.
At the time of the Advisory Committee recommendation, Phase IV was
under development by the Partnership. It was to be based on Composite
Correction Program (CCP) (USEPA 1991) procedures and performance goals,
and was to be awarded based on an on-site evaluation by a third-party
team. The performance goals for Phase IV were such that, over a year,
each sedimentation basin and each filter would need to produce
specified turbidity levels based on the maximum of all the values
recorded during the day. Sedimentation performance goals were set at
2.0 NTU if the raw water was greater than 10 NTU on an annual basis and
1.0 NTU if the raw water was less than 10 NTU. Each filter was to meet
0.1 NTU 95% of the time except for the 15 minute period following
placing the filter in operation. In addition, filters were expected to
have maximum turbidity of 0.3 NTU and return to less than 0.1 NTU
within 15 minutes of the filter being placed in service.
The primary purpose of the on-site evaluation was to confirm that
the performance of the plant was consistent with Phase IV performance
goals and that the system had the administrative support and
operational capabilities to sustain the performance long-term. The on-
site evaluation in Phase IV also allowed utilities that could not meet
the desired performance goals to demonstrate to the third-party that
they had achieved the highest level of performance given their unique
raw water quality.
After the signing of the Stage 2 M-DBP Agreement in Principle in
September 2000, the Partnership decided to eliminate the on-site third-
party evaluation as a component of Phase IV. Instead, the requirement
for Phase IV is for the water system to complete an application package
that will be reviewed by trained utility volunteers. Included in the
application package is an Optimization Assessment Spreadsheet in which
the system enters water quality and treatment data to demonstrate that
Phase IV performance levels have been achieved. The application also
requires narratives related to administrative support and operational
capabilities to sustain performance long-term.
Today's proposal is consistent with the performance goals of Phase
IV.

[[Page 47714]]

Rather than require systems to complete an application package with
historical data and narratives, the LT2ESWTR requires systems to
demonstrate to the State that they meet the individual filter
performance goals of Phase IV on an ongoing basis to receive the 1.0
log additional Cryptosporidium treatment credit. EPA is not requiring
systems to demonstrate that they meet sedimentation performance goals
of Phase IV. While EPA recognizes that settled water turbidity is an
important operational performance measure for a plant, the Agency does
not have data directly relating it to finished water quality and
pathogen risk.
The November 2001 pre-proposal draft of the LT2ESWTR described a
potential 1.0 log credit for systems that achieved individual filter
effluent (IFE) turbidity below 0.15 NTU in 95 percent of samples (USEPA
2001g). The Science Advisory Board (SAB) subsequently reviewed this
credit and supporting data on the relationship between filter effluent
turbidity and Cryptosporidium removal efficiency (described in section
IV.C.8). In written comments from a December 2001 meeting of the
Drinking Water Committee, an SAB panel recommended only a 0.5 log
credit for 95th percentile IFE turbidity below 0.15 NTU.
To address this recommendation from the SAB, EPA is proposing that
systems meet the individual filter performance criteria of Phase IV of
the Partnership in order to be eligible for a 1.0 log additional
Cryptosporidium treatment credit. This proposed approach responds to
the concerns raised by the SAB because the Phase IV criteria are more
stringent than those in the 2001 pre-proposal draft of the LT2ESWTR.
For example, today's proposal sets a maximum limit on individual filter
effluent turbidity of 0.3 NTU, whereas no such upper limit was
described in the 2001 pre-proposal draft.
In summary, EPA has concluded that it is appropriate to award
additional Cryptosporidium treatment credit for systems meeting
stringent individual filter performance standards. Modestly elevated
turbidity from a single filter may not significantly impact combined
filter effluent turbidity levels, which are regulated under IESWTR and
LT1ESWTR, but may indicate a substantial reduction in the overall
pathogen removal efficiency of the filtration process. Consequently,
systems that continually achieve very low turbidity in each individual
filter are likely to provide a significantly more effective microbial
barrier. EPA expects that systems that select this toolbox option will
have achieved a high level of treatment process optimization and
process control, and will have both a history of consistent performance
over a range of raw water quality conditions and the capability and
resources to maintain this performance long-term.
c. Request for comment. The Agency invites comment on the following
issues related to the proposed credit for individual filter
performance.
[sbull] Are there different or additional performance measures that
a utility should be required to meet for the 1 log additional credit?
[sbull] Are there existing peer review programs for which treatment
credit should be awarded under the LT2ESWTR? If so, what role should
primacy agencies play in establishing and managing any such peer review
program?
[sbull] The individual filter effluent turbidity criterion of 0.1
NTU is proposed because it is consistent with Phase IV Partnership
standards, as based on CCP goals. However, with allowable rounding,
turbidity levels less than 0.15 NTU are in compliance with a standard
of 0.1. Consequently, EPA requests comment on whether 0.15 NTU should
be the standard for individual filter performance credit, as this would
be consistent with the standard of 0.15 NTU that is proposed for
combined filter performance credit in section IV.C.8.
17. Other Demonstration of Performance
a. What is EPA proposing today? The purpose of the ``demonstration
of performance'' toolbox component is to allow a system to demonstrate
that a plant, or a unit process within a plant, should receive a higher
Cryptosporidium treatment credit than is presumptively awarded under
the LT2ESWTR. For example, as described in section IV.A, plants using
conventional treatment receive a presumptive 3 log credit towards the
Cryptosporidium treatment requirements in Bins 2-4 of the LT2ESWTR.
This credit is based on a determination by EPA that conventional
treatment plants achieve an average Cryptosporidium removal of 3 log
when in compliance with the IESWTR or LT1ESWTR. However, EPA recognizes
that some conventional treatment plants may achieve average
Cryptosporidium removal efficiencies greater than 3 log. Similarly,
some systems may achieve Cryptosporidium reductions with certain
toolbox components that are greater than the presumptive credits
awarded under the LT2ESWTR, as described in this section (IV.C).
Where a system can demonstrate that a plant, or a unit process
within a plant, achieves a Cryptosporidium reduction efficiency greater
than the presumptive credit specified in the LT2ESWTR, it may be
appropriate for the system to receive a higher Cryptosporidium
treatment credit. Today's proposal does not include specific protocols
for systems to make such a demonstration, due to the potentially
complex and site specific nature of the testing that would be required.
Rather, today's proposal allows a State to award a higher level of
Cryptosporidium treatment credit to a system where the State
determines, based on site-specific testing with a State-approved
protocol, that a treatment plant or a unit process within a plant
reliably achieves a higher level of Cryptosporidium removal on a
continuing basis. Also, States may award a lower level of
Cryptosporidium treatment credit to a system where a State determines,
based on site specific information, that a plant or a unit process
within a plant achieves a Cryptosporidium removal efficiency less than
a presumptive credit specified in the LT2ESWTR.
Systems receiving additional Cryptosporidium treatment credit
through a demonstration of performance may be required by the State to
report operational data on a monthly basis to establish that conditions
under which demonstration of performance credit was awarded are
maintained during routine operation. The Toolbox Guidance Manual (USEPA
2003f) will describe potential approaches to demonstration of
performance testing. This guidance is available in draft in the docket
for today's proposal (http://www.epa.gov/edocket/).
Note that as described in section IV.C, today's proposal allows
treatment plants to achieve additional Cryptosporidium treatment credit
through meeting the design and/or operational criteria of microbial
toolbox components, such as combined and individual filter performance,
presedimentation, bank filtration, two-stage softening, secondary
filtration, etc. Plants that receive additional Cryptosporidium
treatment credit through a demonstration of performance are not also
eligible for the presumptive credit associated with microbial toolbox
components if the additional removal due to the toolbox component is
captured in the demonstration of performance credit. For example, if a
plant receives a demonstration of performance credit based on removal
of Cryptosporidium or an indicator while operating under conditions of
lower finished water turbidity, the plant may not also receive
additional presumptive credit for lower

[[Page 47715]]

finished water turbidity toolbox components.
This demonstration of performance credit does not apply to the use
of chlorine dioxide, ozone, or UV light, because today's proposal
includes specific provisions allowing the State to modify the standards
for awarding disinfection credit to these technologies. As described in
section IV.C.14, States can approve site-specific CT values for
inactivation of Cryptosporidium by chlorine dioxide and ozone; as
described in section IV.C.15, States can approve an alternative
approach for validating the performance of UV reactors.
b. How was this proposal developed? The Stage 2 M-DBP Agreement in
Principle recommends demonstration of performance as a process for
systems to receive Cryptosporidium treatment credit higher than the
presumptive credit for many microbial toolbox components, as well as
credit for technologies not listed in the toolbox. EPA is aware that
there may be plants where particular unit processes, or combinations of
unit processes, achieve greater Cryptosporidium removal than the
presumptive credit awarded under the LT2ESWTR. In addition, the Agency
would like to allow for the use of Cryptosporidium treatment processes
not addressed in the LT2ESWTR, where such processes can demonstrate a
reliable specific log removal. Due to these factors, EPA is proposing a
demonstration of performance component in the microbial toolbox,
consistent with the Advisory Committee recommendation.
The Agreement in Principle makes no recommendations for how a
demonstration of performance should be conducted. It is generally not
practical for systems to directly quantify high log removal of
Cryptosporidium in treatment plants because of the relatively low
occurrence of Cryptosporidium in many raw water sources and limitations
with analytical methods. Consequently, if systems are to demonstrate
the performance of full scale plants in removing Cryptosporidium, this
typically will require the use of indicators, where the removal of the
indicator has been correlated with the removal of Cryptosporidium. As
described previously, a number of studies have shown that aerobic
spores are an indicator of Cryptosporidium removal by sedimentation and
filtration (Dugan et al. 2001, Emelko et al. 1999 and 2000, Yates et
al. 1998, Mazounie et al. 2000).
The nature of demonstration of performance testing that will be
appropriate at a given facility will depend on site specific factors,
such as water quality, the particular process(es) being evaluated,
resources and infrastructure, and the discretion of the State.
Consequently, EPA is not proposing specific criteria for demonstration
of performance testing. Instead, systems must develop a testing
protocol that is approved by the State, including any requirements for
ongoing reporting if demonstration of performance credit is approved.
EPA has developed a draft document, Toolbox Guidance Manual (USEPA
2003f), that is available with today's proposal and provides guidance
on demonstration of performance testing.
c. Request for comment. The Agency requests comment on today's
proposal for systems to demonstrate higher Cryptosporidium removal
levels. EPA specifically requests comment on the following issues:
[sbull] Approaches that should be considered or excluded for
demonstration of performance testing;
[sbull] Whether EPA should propose minimum elements that
demonstration of performance testing must include;
[sbull] Whether a factor of safety should be applied to the results
of demonstration of performance testing to account for potential
differences in removal of an indicator and removal of Cryptosporidium,
or uncertainty in the application of pilot-scale results to full-scale
plants;
[sbull] Whether or under what conditions a demonstration of
performance credit should be allowed for a unit process within a
plant--a potential concern is that certain unit processes, such as a
sedimentation basin, can be operated in a manner that will increase
removal in the unit process but decrease removal in subsequent
treatment processes and, therefore, lead to no overall increase in
removal through the plant. An approach to address this concern is to
limit demonstration of performance credit to removal demonstrated
across the entire treatment plant.

D. Disinfection Benchmarks for Giardia lamblia and Viruses

1. What Is EPA Proposing Today?
EPA proposes to establish the disinfection benchmark under the
LT2ESWTR as a procedure to ensure that systems maintain protection
against microbial pathogens as they implement the Stage 2 M-DBP rules
(i.e., Stage 2 DBPR and LT2ESWTR). The disinfection benchmark serves as
a tool for systems and States to evaluate the impact on microbial risk
of proposed changes in disinfection practice. EPA established the
disinfection benchmark under the IESWTR and LT1ESWTR for the Stage 1 M-
DBP rules, as recommended by the Stage 1 M-DBP Advisory Committee.
Today's proposal extends disinfection benchmark requirements to apply
to the Stage 2 M-DBP rules.
Under the proposed LT2ESWTR, the disinfection benchmark procedure
involves a system charting levels of Giardia lamblia and virus
inactivation at least once per week over a period of at least one year.
This creates a profile of inactivation performance that the System must
use to determine a baseline or benchmark of inactivation against which
proposed changes in disinfection practice can be measured. Only certain
systems are required to develop profiles and keep them on file for
State review during sanitary surveys. When those systems that are
required to develop a profile plan a significant change in disinfection
practice (defined later in this section), they must submit the profile
and an analysis of how the proposed change will affect the current
disinfection benchmark to the State for review.
Systems that developed disinfection profiles under the IESWTR or
LT1ESWTR and have not made significant changes in their disinfection
practice or changed sources are not required to collect additional
operational data to create disinfection profiles under the LT2ESWTR.
Systems that produced a disinfection profile for Giardia lamblia but
not viruses under the IESWTR or LT1ESWTR may be required to develop a
profile for viruses under the LT2ESWTR. Where a previously developed
Giardia lamblia profile is acceptable, systems may develop a virus
profile using the same operational data (i.e., CT values) on which the
Giardia lamblia profile is based. Spreadsheets developed by EPA and
States automatically calculate Giardia lamblia and virus profiles using
the same operational data. EPA believes that virus profiling is
necessary because many of the disinfection processes that systems will
select to comply with the Stage 2 DBPR and LT2ESWTR (e.g., chloramines,
UV, MF/UF) are relatively less effective against viruses than Giardia
lamblia in comparison to free chlorine.
The disinfection benchmark provisions contain three major
components: (a) Applicability requirements and schedule, (b)
characterization of disinfection practice, and (c) State review of
proposed changes in disinfection practice. Each of these components is
discussed in the following paragraphs.

[[Page 47716]]

a. Applicability and schedule. Proposed disinfection profiling and
benchmarking requirements apply to surface water systems only. Systems
serving only ground water are not subject to the requirements of the
LT2ESWTR. The determination of whether a surface water system is
required to develop a disinfection profile is based on whether DBP
levels (TTHM or HAA5) exceed specified values, described later in this
section, and whether a system is required to monitor for
Cryptosporidium. These criteria trigger profiling because they identify
systems that may be required to make treatment changes under the Stage
2 DBPR or LT2ESWTR. Note that it is not practical to wait until a
system has completed Cryptosporidium monitoring to identify which
systems should prepare a disinfection profile. A completed disinfection
profile should be available at the point when a system is classified in
a treatment bin and must begin developing plans to comply with any
additional treatment requirements.
Unless the system developed a disinfection profile under the IESWTR
or LT1ESWTR, all systems required to monitor for Cryptosporidium must
develop Giardia lamblia and virus disinfection profiles under the
LT2ESWTR. This includes all surface water systems except (1) systems
that provide 5.5 log total treatment for Cryptosporidium, equivalent to
meeting the treatment requirements of Bin 4 and (2) small systems
(<10,000 people served) that do not exceed the E. coli trigger (see
section IV.A for details). Systems not required to monitor for
Cryptosporidium as a result of providing 5.5 log of treatment are not
required to prepare disinfection profiles. However, small systems that
do not exceed the E. coli trigger are required to prepare Giardia
lamblia and virus disinfection profiles if one of the following
criteria apply, based on DBP levels in their distribution systems:
(1)* TTHM levels in the distribution system, based on samples
collected for compliance with the Stage 1 DBPR, are at least 80% of the
MCL (0.064 mg/L) at any Stage 1 DBPR sampling point based on a
locational running annual average (LRAA).
(2)* HAA5 levels in the distribution system, based on the samples
collected for compliance with the Stage 1 DBPR, are at least 80% of the
MCL (0.048 mg/L) at any Stage 1 DBPR sampling point based on an LRAA.

*These criteria only apply to systems that are required to comply with
the DBP rules, i.e., community and non-transient non-community systems.
Table IV-22 presents a summary schedule of the required deadlines
for disinfection profiling activities, categorized by system size and
whether a small system is required to monitor for Cryptosporidium. The
deadlines are based on the expectation that a system should have a
disinfection profile at the time the system is classified in a
Cryptosporidium treatment bin under LT2ESWTR and/or has determined the
need to make treatment changes for the Stage 2 DBPR. Systems have three
years from this date, with a possible two year extension for capital
improvements if granted by the State, within which to complete their
evaluation, design, and implementation of treatment changes to meet the
requirements of the LT2ESWTR and the Stage 2 DBPR.

Table IV-22.--Schedule of Implementation Deadlines Related to Disinfection Profiling \1\
----------------------------------------------------------------------------------------------------------------
Systems serving <10,000 people
---------------------------------
Systems serving Not required to
Activity =10,000 Required to monitor for
people \2\ monitor for Cryptosporidium
Cryptosporidium ² ³ ⁶
----------------------------------------------------------------------------------------------------------------
Complete 1 year of E. coli monitoring..................... NA 42 42
Determine whether required to profile based on DBP levels NA NA 42
and notify State \6\.....................................
Begin disinfection profiling\4\........................... 24 54 42
Complete Cryptosporidium monitoring....................... 30 60 NA
Complete disinfection profiling based on at least one 36 66 54
year's data \5\..........................................
----------------------------------------------------------------------------------------------------------------
\1\ Numbers in table indicate months following promulgation of the LT2ESWTR.
\2\ Systems providing a total of 5.5 log Cryptosporidium treatment (equivalent to meeting Bin 4 treatment
requirements) are not required to develop disinfection profiles.
\3\ Systems serving fewer than 10,000 people are not required to monitor for Cryptosporidium if mean E. coli
levels are less than 10/100 mL for systems using lake/reservoir sources or less than 50/100 mL for systems
using flowing stream sources.
\4\ Unless system has existing disinfection profiling data that are acceptable.
\5\ This deadline coincides with the start of the 3 year period at the end of which compliance with the LT2ESWTR
and Stage 2 DBPR is required.
\6\ Not required to conduct profiling unless TTHM or HAA5 exceeds trigger values of 80% of MCL at any sampling
point based on LRAA.

As described in the next section, systems can meet profiling
requirements under the proposed LT2ESWTR using previously collected
data (i.e., grandfathered data). Use of grandfathered data is allowed
if the system has not made a significant change in disinfection
practice or changed sources since the data were collected. This will
permit most systems that prepared a disinfection profile under the
IESWTR or the LT1ESWTR to avoid collecting any new operational data to
develop profiles under the LT2ESWTR.
The locational running annual average (LRAA) of TTHM and HAA5
levels used by small systems that do not monitor for Cryptosporidium to
determine whether profiling is required must be based on one year of
DBP data collected during the period following promulgation of the
LT2ESWTR, or as determined by the State. By the date indicated in Table
IV-22, these systems must report to the State on their DBP LRAAs and
whether the disinfection profiling requirements apply. If either DBP
LRAA meets the criteria specified previously, the system must begin
disinfection profiling by the date proposed in Table IV-22.
b. Developing the disinfection profile and benchmark. Under the
LT2ESWTR, a disinfection profile consists of a compilation of Giardia
lamblia and virus log inactivation levels computed at least weekly over
a period of at least one year, as based on operational and water
quality data (disinfectant residual concentration(s), contact time(s),
temperature(s), and, where necessary, pH). The system may create the
profile by conducting new weekly (or more frequent) monitoring and/or
by using

[[Page 47717]]

grandfathered data. A system that created a Giardia lamblia
disinfection profile under the IESWTR or LT1ESWTR may use the
operational data collected for the Giardia lamblia profile to create a
virus disinfection profile.
Grandfathered data are those operational data that a system has
previously collected at a treatment plant during the course of normal
operation. Those systems that have all the necessary information to
determine profiles using existing operational data collected prior to
the date when the system is required to begin profiling may use these
data in developing profiles. However, grandfathered data must be
substantially equivalent to operational data that would be collected
under this rule. These data must be representative of inactivation
through the entire treatment plant and not just of certain treatment
segments.
To develop disinfection profiles under this rule, systems are
required to exercise one of the following three options:
Option 1--Systems conduct monitoring at least once per week
following the process described later in this section.
Option 2--Systems that conduct monitoring under this rule, as
described under Option 1, can also use one or two years of acceptable
grandfathered data, in addition to one year of new operational data, in
developing the disinfection profile.
Option 3--Systems that have at least one year of acceptable
existing operational data are not required to conduct new monitoring to
develop the disinfection profile under this rule. Instead, they can use
a disinfection profile based on one to three years of grandfathered
data.
Process to be followed by PWS for developing the disinfection
profile:

--Measure disinfectant residual concentration (C, in mg/L) before or at
the first customer and just prior to each additional point of
disinfectant addition, whether with the same or a different
disinfectant.
--Determine contact time (T, in minutes) for each residual disinfectant
monitoring point during peak flow conditions. T could be based on
either a tracer study or assumptions based on contactor basin geometry
and baffling. However, systems must use the same method for both
grandfathered data and new data.
--Measure water temperature ([deg]C) (for disinfectants other than UV).
--Measure pH (for chlorine only).

To determine the weekly log inactivation, the system must convert
operational data from one day each week to the corresponding log
inactivation values for Giardia lamblia and viruses. The procedure for
Giardia lamblia is as follows:

--Determine CTcalc for each disinfection segment.
--Determine CT99.9 (i.e., 3 log inactivation) from tables in
the SWTR (40 CFR 141.74) using temperature (and pH for chlorine) for
each disinfection segment. States can allow an alternate calculation
procedure (e.g., use of a spreadsheet).
--For each segment, log inactivation = (CTcalc/
CT99.9) x 3.0.
--Sum the log inactivation values for each segment to get the log
inactivation for the day (or week).

For calculating the virus log inactivation, systems should use the
procedures approved by States under the IESWTR or LT1ESWTR. Log
inactivation benchmark is calculated as follows:

--Determine the calendar month with the lowest log inactivation.
--The lowest month becomes the critical period for that year.
--If acceptable data from multiple years are available, the average of
critical periods for each year becomes the benchmark.
--If only one year of data is available, the critical period for that
year is the benchmark.

c. State review. If a system that is required to produce a
disinfection profile proposes to make a significant change in
disinfection practice, it must calculate Giardia lamblia and virus
inactivation benchmarks and must notify the State before implementing
such a change. Significant changes in disinfection practice are defined
as (1) moving the point of disinfection (this is not intended to
include routine seasonal changes already approved by the State), (2)
changing the type of disinfectant, (3) changing the disinfection
process, or (4) making other modifications designated as significant by
the State. When notifying the State, the system must provide a
description of the proposed change, the disinfection profiles and
inactivation benchmarks for Giardia lamblia and viruses, and an
analysis of how the proposed change will affect the current
inactivation benchmarks. In addition, the system should have
disinfection profiles and, if applicable, inactivation benchmarking
documentation, available for the State to review as part of its
periodic sanitary survey.
EPA developed for the IESWTR, with stakeholder input, the
Disinfection Profiling and Benchmarking Guidance Manual (USEPA 1999d).
This manual provides guidance to systems and States on the development
of disinfection profiles, identification and evaluation of significant
changes in disinfection practices, and considerations for setting an
alternative benchmark. If necessary, EPA will produce an addendum to
reflect changes in the profiling and benchmarking requirements
necessary to comply with LT2ESWTR.
2. How Was This Proposal Developed?
A fundamental premise in the development of the M-DBP rules is the
concept of balancing risks between DBPs and microbial pathogens.
Disinfection profiling and benchmarking were established under the
IESWTR and LT1ESWTR, based on a recommendation by the Stage 1 M-DBP
Federal Advisory Committee, to ensure that systems maintained adequate
control of pathogen risk as they reduced risk from DBPs. Today's
proposal would extend disinfection benchmarking requirements to the
LT2ESWTR.
EPA believes this extension is necessary because some systems will
make significant changes in their current disinfection practice to meet
more stringent limits on TTHM and HAA5 levels under the Stage 2 DBPR
and additional Cryptosporidium treatment requirements under the
LT2ESWTR. In order to ensure that these systems continue to provide
adequate protection against the full spectrum of microbial pathogens,
it is appropriate for systems and States to evaluate the effects of
such treatment changes on microbial drinking water quality. The
disinfection benchmark serves as a tool for making such evaluations.
EPA projects that to comply with the Stage 2 DBPR, systems will
make changes to their disinfection practice, including switching from
free chlorine to chloramines and, to a lesser extent, installing
technologies like ozone, membranes, and UV. Similarly, to provide
additional treatment for Cryptosporidium, some systems will install
technologies like UV, ozone, and microfiltration. While these processes
are all effective disinfectants, chloramines are a weaker disinfectant
than free chlorine for Giardia lamblia. Ozone, UV, and membranes can
provide highly effective treatment for Giardia lamblia, but they, as
well as chloramines, are less efficient for treating viruses than free
chlorine, relative to their efficacy for Giardia lamblia. Because of
this, a system switching from free chlorine to one of these alternative
disinfection

[[Page 47718]]

technologies could experience a reduction in the level of virus and/or
Giardia lamblia (for chloramines) treatment it is achieving.
Consequently, EPA believes that systems making significant changes in
their disinfection practice under the Stage 2 M-DBP rules should assess
the impact of these changes with disinfection benchmarks for Giardia
lamblia and viruses.
Changes in the proposed benchmarking requirements under the
LT2ESWTR in comparison to IESWTR requirements include decreasing the
frequency of calculating CT values for the disinfection profile from
daily to weekly and requiring all systems to prepare a profile for
viruses as well as Giardia lamblia. The proposal of a weekly frequency
for CT calculations was made to accommodate existing profiles from
small systems, which are required to make weekly CT calculations for
profiling under the LT1ESWTR. As described earlier, EPA would like for
systems that have prepared a disinfection profile under the IESWTR or
LT1ESWTR and have not subsequently made significant changes in
disinfection practice to be able to grandfather this profile for the
LT2ESWTR. Allowing weekly calculation of CT values under the LT2ESWTR
will make this possible.
The IESWTR and LT1ESWTR required virus inactivation profiling only
for systems using ozone or chloramine as their primary disinfectant.
However, as noted earlier, EPA has projected that under the Stage 2
DBPR and LT2ESWTR, systems will switch from free chlorine to
disinfection processes like chloramines, UV, ozone, and
microfiltration. The efficiency of these processes for virus treatment
relative to protozoa treatment is lower in comparison to free chlorine.
As a result, a disinfection benchmark for Giardia lamblia would not
necessarily provide an indication of the level or adequacy of treatment
for viruses. Consequently, EPA believes it is appropriate for systems
to develop profiles for both Giardia lamblia and viruses. Moreover,
developing a profile for viruses involves a minimal increase in effort
and no additional data collection for those systems that have
disinfection profiles for Giardia lamblia. Systems will use the same
calculated CT values for viruses as would be used for the Giardia
lamblia profile.
The strategy of disinfection profiling and benchmarking stemmed
from data provided to the Stage1 M-DBP Advisory Committee, in which the
baseline of microbial inactivation (expressed as logs of Giardia
lamblia inactivation) demonstrated high variability. Inactivation
varied by several logs (i.e., orders of magnitude) on a day-to-day
basis at particular treatment plants and by as much as tens of logs
over a year due to changes in water temperature, flow rate, seasonal
changes, pH, and disinfectant demand. There were also differences
between years at individual plants. To address these variations, M-DBP
stakeholders developed the procedure of profiling a plant's
inactivation levels over a period of at least one year, and then
establishing a benchmark of minimum inactivation as a way to
characterize disinfection practice.
Benchmarking of inactivation levels, an assessment of the impact of
proposed changes on the level of microbial inactivation of Giardia
lamblia and viruses, and State review prior to approval of substantial
changes in treatment are important steps in avoiding conditions that
present an increase in microbial risk. In its assessment of the
microbial risk associated with the proposed changes, States could
consider site-specific knowledge of the watershed and hydrologic
factors as well as variability, flexibility and reliability of
treatment to ensure that treatment for both protozoan and viral
pathogens is appropriate.
EPA emphasizes that benchmarking is not intended to function as a
regulatory standard. Rather, the objective of the disinfection
benchmark is to facilitate interactions between the States and systems
for the purpose of assessing the impact on microbial risk of proposed
significant changes to current disinfection practices. Final decisions
regarding levels of disinfection for Giardia lamblia and viruses beyond
those required by the SWTR that are necessary to protect public health
will continue to be left to the States. For this reason EPA has not
mandated specific evaluation protocols or decision matrices for
analyzing changes in disinfection practice. EPA, however, will provide
support to the States in making these analyses through the issuance of
guidance.
3. Request for Comments
EPA requests comment on the proposed provisions of the inactivation
profiling and benchmarking requirement.

E. Additional Treatment Technique Requirements for Systems With
Uncovered Finished Water Storage Facilities

1. What Is EPA Proposing Today?
EPA is proposing requirements for systems with uncovered finished
water storage facilities. The proposed rule requires that systems with
uncovered finished water storage facilities must (1) cover the
uncovered finished water storage facility, or (2) treat storage
facility discharge to the distribution system to achieve a 4 log virus
inactivation, unless (3) the system implements a State-approved risk
mitigation plan that addresses physical access and site security,
surface water runoff, animal and bird waste, and ongoing water quality
assessment, and includes a schedule for plan implementation. Where
applicable, the plans should account for cultural uses by Indian
Tribes.
Systems must notify the State if they use uncovered finished water
storage facilities no later than 2 years following LT2ESWTR
promulgation. Systems must cover or treat uncovered finished facilities
or have a State-approved risk mitigation plan within 3 years following
LT2ESWTR promulgation, with the possibility of a two year extension
granted by States for systems making capital improvements. Systems
seeking approval for a risk mitigation plan must submit the plan to the
State within 2 years following LT2ESWTR promulgation.
These provisions apply to uncovered tanks, reservoirs, or other
facilities where water is stored after it has undergone treatment to
satisfy microbial treatment technique requirements for Giardia lamblia,
Cryptosporidium, and viruses. In most cases, this refers to storage of
water following all filtration steps, where required, and primary
disinfection.
2. How Was This Proposal Developed?
Today's proposal is intended to mitigate the water quality
degradation and increased health risks that can result from uncovered
finished water storage facilities. In addition, these proposed
requirements for uncovered finished water storage facilities are
consistent with recommendations of the Stage 2 M-DBP Advisory Committee
in the Agreement in Principle (USEPA 2000a).
The use of uncovered finished water storage facilities has been
questioned since 1930 due to their susceptibility to contamination and
subsequent threats to public health (LeChevallier et al. 1997). Many
potential sources of contamination can lead to the degradation of water
quality in uncovered finished water storage facilities. These include
surface water runoff, algal growth, insects and fish, bird and animal
waste, airborne deposition, and human activity.

[[Page 47719]]

Algal blooms are the most common problem in open reservoirs and can
become a public health risk, as they increase the presence of bacteria
in the water. Algae growth also leads to the formation of disinfection
byproducts and causes taste and odor problems. Some algae produce
toxins that can induce headache, fever, diarrhea, abdominal pain,
nausea, and vomiting. Bird and animal wastes are also common and
significant sources of contamination. These wastes may carry microbial
contaminants such as coliform bacteria, viruses, and human pathogens,
including Vibrio cholera, Salmonella, Mycobacteria, Typhoid, Giardia
lamblia, and Cryptosporidium (USEPA 1999e). Microbial pathogens are
found in surface water runoff, along with agricultural chemicals,
automotive wastes, turbidity, metals, and organic matter (USEPA 1999e,
LeChevallier et al. 1997).
In an effort to minimize contamination, systems have implemented
various controls such as reservoir covers and liners, regular draining
and washing, security and monitoring, bird and insect control programs,
and drainage design to prevent surface runoff from entering the
facility (USEPA 1999e).
A number of studies have evaluated the degradation of water quality
in uncovered finished water storage facilities. LeChevallier et al.
(1997) compared influent and effluent samples from six uncovered
finished water storage reservoirs in New Jersey for a one year period.
There were significant increases in the turbidity, particle count,
total coliform, fecal coliform, and heterotrophic plate count bacteria
in the effluent relative to the influent. Of particular concern were
fecal coliforms, which were detected in 18 percent of effluent samples
(no influent samples were positive for coliforms). Fecal coliforms are
used as an indicator of the potential for contamination by pathogens.
Giardia and/or Cryptosporidium were detected in 15% of inlet samples
and 25% of effluent samples, demonstrating a significant increase in
the effluent. There was a significant decrease in the chlorine residual
concentration in some effluent samples.
Increases in algal cells, heterotrophic plate count (HPC) bacteria,
turbidity, color, particle counts, and biomass, and decreases in
residual chlorine levels, have been reported in other studies of
uncovered finished water reservoirs as well (Pluntze 1974, AWWA
Committee 1983, Silverman et al. 1983). Researchers have shown that
small mammals, birds, fish, and algal growth contribute to the
microbial degradation of an open finished water reservoir (Graczyk et
al. 1996, Geldreich 1990, Fayer and Ungar 1986, Current 1986).
As described in section II, the IESWTR and LT1ESWTR require water
systems to cover all new reservoirs, holding tanks, or other storage
facilities for finished water. However, these rules do not require
systems to cover existing finished water storage facilities. EPA stated
in the preamble to the final IESWTR (63 FR 69494, December 16, 1998)
(USEPA 1998a) that with respect to requirements for existing uncovered
finished water storage facilities, the Agency needed more time to
collect and analyze additional information to evaluate regulatory
impact. The IESWTR preamble affirmed that EPA would consider whether to
require the covering of existing storage facilities during the
development of subsequent microbial regulations when additional data to
estimate national costs were available.
Since promulgation of the IESWTR, EPA has collected sufficient data
to estimate national cost implications of regulatory control strategies
for uncovered finished water storage facilities. Based on information
provided by States, EPA estimates that there are approximately 138
uncovered finished water storage facilities in the United States and
territories, not including reservoirs that systems currently plan to
cover or take off-line. Costs for covering these storage facilities or
treating the effluent, consistent with today's proposed requirements,
are presented in section VI of this preamble and in the Economic
Analysis for the LT2ESWTR (USEPA 2003a). Briefly, total capital costs
were estimated as $64.4 million, resulting in annualized present value
costs of $5.4 million at a three percent discount rate and $6.4 million
at a seven percent discount rate.
Based on the findings of studies cited in this section, EPA
continues to be concerned about contamination occurring in uncovered
finished water storage facilities. Therefore, as recommended by the
Advisory Committee, EPA is proposing control measures for all systems
with uncovered finished water storage facilities. This proposal is
intended to represent a balanced approach, recognizing both the
potentially significant but uncertain risks associated with uncovered
finished water storage facilities and the substantial costs of either
covering them or building alternative storage. Today's proposal allows
systems to treat the storage facility effluent instead of providing a
cover. Alternatively, States may determine that existing risk
mitigation is adequate, provided a system implements a risk mitigation
plan as described in this section.
3. Request for Comments
EPA requests comment on the proposed requirements pertaining to
uncovered finished water storage facilities. Specifically, the Agency
would like comment on the following issues, and requests that comments
include available supporting data or other technical information:
[sbull] Is it appropriate to allow systems with uncovered finished
water storage facilities to implement a risk management plan or treat
the effluent to inactivate viruses instead of covering the facility?
[sbull] If systems treat the effluent of an uncovered finished
water storage facility instead of covering it, should systems be
required to inactivate Cryptosporidium and Giardia lamblia, since these
protozoa have been found to increase in uncovered storage facilities?
[sbull] Additional information on contamination or health risks
that may be associated with uncovered finished water storage
facilities.
[sbull] Additional data on how climatological conditions affect
water quality, including daily fluctuations in the stability of the
water related to corrosion control.
[sbull] The definition of an uncovered finished water storage
facility in 40 CFR 141.2 is a tank, reservoir, or other facility used
to store water that will undergo no further treatment except residual
disinfection and is open to the atmosphere. There is a concern that
this definition may not include certain systems using what would
generally be considered an uncovered finished water storage facility.
An example is a system that applies a corrosion inhibitor compound to
the effluent of an uncovered storage facility where water is stored
after filtration and primary disinfection. In this case, the system may
claim that the corrosion inhibitor constitutes additional treatment
and, consequently, the reservoir does not meet EPA's definition of an
uncovered finished water storage facility. EPA requests comment on
whether the definition of an uncovered finished water storage facility
should be revised to specifically include systems that apply a
treatment such as corrosion control to water stored in an uncovered
reservoir after the water has undergone filtration, where required, and
primary disinfection.

F. Compliance Schedules

Today's proposal includes deadlines for public water systems to
comply with

[[Page 47720]]

the proposed monitoring, reporting, and treatment requirements. These
deadlines stem from the microbial framework approach of the proposed
LT2ESWTR, which involves a system-specific risk characterization
through monitoring to determine the need for additional treatment.
1. What Is EPA Proposing Today?
a. Source water monitoring.
i. Filtered systems. Under today's proposal, filtered systems
conduct source water Cryptosporidium monitoring for the purpose of
being classified in one of four risk bins that determine the extent of
any additional treatment requirements. Small filtered systems first
monitor for E. coli as a screening analysis and are only required to
monitor for Cryptosporidium if the mean E. coli level exceeds specified
trigger values. Note that systems that currently provide or will
provide a total of at least 5.5 log of treatment for Cryptosporidium
are exempt from monitoring requirements.
Large surface water systems (serving at least 10,000 people) that
filter must sample at least monthly for Cryptosporidium, E. coli, and
turbidity in their source water for 24 months, beginning 6 months after
promulgation of the LT2ESWTR. Large systems must submit a sampling
schedule to their primacy agency (in this case, EPA) no later than 3
months after promulgation of the LT2ESWTR.
Small surface water systems (fewer than 10,000 people served) that
filter must conduct biweekly E. coli sampling in their source water for
1 year, beginning 30 months after LT2ESWTR promulgation. States may
designate an alternate indicator monitoring strategy based on EPA
guidance, but compliance schedules will not change. Small systems that
exceed the indicator trigger value (i.e., mean E. coli 10/
100 mL for lake/reservoir sources or 50/100 mL for flowing
stream sources) must conduct source water Cryptosporidium sampling
twice-per-month for 1 year, beginning 48 months after LT2ESWTR
promulgation (i.e., beginning 6 months following the completion of E.
coli sampling). Small systems must submit an E. coli sampling schedule
to their primacy agency no later than 27 months after LT2ESWTR
promulgation. If Cryptosporidium monitoring is required, small systems
must submit a Cryptosporidium sampling schedule no later than 45 months
after LT2ESWTR promulgation.
Large systems must carry out a second round of source water
monitoring beginning 108 months after LT2ESWTR promulgation, which is 6
years after initial bin classification. Similarly, small systems must
conduct a second round of indicator monitoring (E. coli or other as
designated by the State) beginning 138 months after LT2ESWTR
promulgation, which is 6 years after their initial bin classification.
Small systems that exceed the indicator trigger value in the second
round of indicator monitoring must conduct a second round of
Cryptosporidium monitoring, beginning 156 months after LT2ESWTR
promulgation.
Compliance dates for filtered systems are summarized in Table IV-
23.

Table IV-23.--Summary of Compliance Dates for Filtered Systems
------------------------------------------------------------------------
System type Requirement Compliance date
------------------------------------------------------------------------
Large Systems (serve =10,000 people). schedule ^1,2. months after
promulgation.
Source water Begin monthly
Cryptosporidium, monitoring 6
E. coli and months after
turbidity promulgation for
monitoring. 24 months.
Comply with No later than 72
additional months after
Cryptosporidium promulgation.³
treatment
requirements.
Second round of Begin monthly
source water monitoring 108
Cryptosporidium, months after
E. coli, and promulgation for
turbidity 24 months.
monitoring ².
Small Systems (serve <10,000 Submit E. coli No later than 27
people). sampling months after
schedule². promulgation.
Source water E. Begin biweekly
coli monitoring. monitoring 30
months after
promulgation for
1 year.
Second round of Begin biweekly
source water E. monitoring 138
coli monitoring ². months after
promulgation for
1 year.
---------------------
Additional requirements if indicator
(e.g., E. coli) trigger level is
exceeded⁴
---------------------
Submit No later than 45
Cryptosporidium months after
sampling schedule promulgation.
^1,2.
Source water Begin twice-per-
Cryptosporidium month monitoring
monitoring. no later than 48
months after
promulgation for
1 year.
Comply with No later than 102
additional months after
Cryptosporidium promulgation.^3, ⁵
treatment
requirements.
Second round of Begin twice-per-
source water month monitoring
Cryptosporidium no later than 156
monitoring. months after
promulgation for
1 year.
------------------------------------------------------------------------
\1\ Systems may be eligible to use previously collected (grandfathered)
data to meet LT2ESWTR requirements if specified quality control
criteria are met (described in section IV.A.1.d).
\2\ Systems are not required to monitor if they will provide at least
5.5 log Cryptosporidium treatment and notify EPA or the State.
\3\ States may grant up to an additional two years for systems making
capital improvements.
\4\ If the E. coli annual mean concentration exceeds 10/100 mL for
systems using lakes/reservoir sources or exceeds 50/100 mL for systems
using flowing stream sources, Cryptosporidium monitoring is required.
\5\ Systems that do not exceed the E. coli trigger level are classified
in Bin 1 and are not required to provide Cryptosporidium treatment
beyond LT1ESWTR levels.

ii. Unfiltered systems. Surface water systems that do not filter
and meet the criteria for avoidance of filtration (40 CFR 141.71)
(i.e., unfiltered systems) are required to conduct source water
Cryptosporidium monitoring to determine if their mean source water
Cryptosporidium level exceeds 0.01 oocysts/L. There is no E. coli
screening analysis available to small unfiltered systems. However, both
large and small unfiltered systems conduct

[[Page 47721]]

Cryptosporidium monitoring on the same schedule as filtered systems of
the same size. Note that unfiltered systems that currently provide or
will provide a total of at least 3 log Cryptosporidium inactivation are
exempt from monitoring requirements.
Large unfiltered systems (serving at least 10,000 people) must
conduct at least monthly Cryptosporidium sampling for 24 months,
beginning 6 months after LT2ESWTR promulgation. Small unfiltered
systems (serving fewer than 10,000 people) must conduct at least twice-
per-month Cryptosporidium sampling for 12 months, beginning 48 months
after LT2ESWTR promulgation. Large systems must submit a
Cryptosporidium sampling schedule to EPA no later than 3 months after
LT2ESWTR promulgation, and small systems must submit a sampling
schedule to their State no later than 45 months after LT2ESWTR
promulgation.
Unfiltered systems are required to conduct a second round of
Cryptosporidium monitoring on the same schedule as filtered systems of
the same size. Large systems must carry out a second round of
Cryptosporidium monitoring, beginning 108 months after LT2ESWTR
promulgation. Small systems must perform a second round of
Cryptosporidium monitoring, beginning 156 months after LT2ESWTR
promulgation.
Compliance dates for unfiltered systems are summarized in Table IV-
24.

Table IV-24.--Summary of Compliance Dates for Unfiltered Systems
------------------------------------------------------------------------
System type Requirement Compliance date
------------------------------------------------------------------------
Large Systems (serve =10,000 people). schedule \1\. months after
promulgation.
Source water Begin monthly
Cryptosporidium monitoring [6
monitoring. months after
promulgation for
24 months.
Comply with No later than 72
Cryptosporidium months after
inactivation promulgation.\2\
requirements.
Second round of Begin monthly
source water monitoring 108
Cryptosporidium months after
monitoring. promulgation for
24 months.
Small Systems (serve < 10,000 Submit sampling No later than 45
people). schedule \1\. months after
promulgation.
Source water Begin twice-per-
Cryptosporidium month monitoring
monitoring. no later than 48
months after
promulgation for
1 year.
Comply with No later than 102
Cryptosporidium months after
inactivation promulgation.\2\
requirements.
Second round of Begin twice-per-
source water month monitoring
Cryptosporidium no later than 156
monitoring. months after
promulgation for
1 year.
------------------------------------------------------------------------
\1\ Systems may be eligible to use previously collected (grandfathered)
data to meet LT2ESWTR requirements if specified quality control
criteria are met (described in section IV.A.1.d).
\2\ States may grant up to an additional two years for systems making
capital improvements.

b. Treatment requirements. Filtered systems must determine their
bin classification and unfiltered systems must determine their mean
source water Cryptosporidium level within 6 months of the scheduled
month for collection of their final Cryptosporidium sample in the first
round of monitoring. This 6 month period provides time for systems to
receive all sample analysis results from the laboratory, analyze the
data, and work with their primacy agency.
Filtered systems have 3 years following initial bin classification
to meet any additional Cryptosporidium treatment requirements. This
equates to compliance dates of 72 months after LT2ESWTR promulgation
for large systems and 102 months after LT2ESWTR promulgation for small
systems (see Table IV-23). Unfiltered systems must comply with
Cryptosporidium treatment requirements on the same schedule as filtered
systems of the same size (see Table IV-24). The State may grant systems
an additional two years to comply when capital investments are
necessary, as specified in the Safe Drinking Water Act (section
1412(b)(10)).
Systems with uncovered finished water storage facilities are
required to comply with the provisions described in section IV.E by 36
months following LT2ESWTR promulgation, with the possibility of a 2
year extension granted by the State for systems making capital
improvements. Systems seeking approval for a risk mitigation plan must
submit the plan to the State within 24 months following LT2ESWTR
promulgation.
Systems must comply with additional Cryptosporidium treatment
requirements by implementing one or more treatment processes or control
strategies from the microbial toolbox. Most of the toolbox components
require submission of documentation to the State demonstrating
compliance with design and/or implementation criteria required to
receive credit. Compliance dates for reporting requirements associated
with microbial toolbox components are presented in detail in section
IV.J, Reporting and Recordkeeping Requirements.
c. Disinfection benchmarks for Giardia lamblia and viruses. Today's
proposed LT2ESWTR includes disinfection profiling and benchmarking
requirements, which consist of three major components: applicability
determination, characterization of disinfection practice, and State
review of proposed changes in disinfection practice. Each of these
components is discussed in detail in section IV.D. Compliance deadlines
associated with each of these components, including associated
reporting requirements, are stated in section IV.J, Reporting and
Recordkeeping Requirements.
2. How Was This Proposal Developed?
The compliance dates in today's proposal reflects the risk-targeted
approach of the proposed LT2ESWTR, wherein additional treatment
requirements are based on a system specific risk characterization as
determined through source water monitoring. Additionally, they are
designed to allow for systems to simultaneously comply with the
LT2ESWTR and Stage 2 DBPR in order to balance risks in the control of
microbial pathogens and DBPs. These dates are consistent with
recommendations from the Stage 2 M-DBP Federal Advisory Committee.
Under the LT2ESWTR, large systems will sample for Cryptosporidium
for a period of two years in order to

[[Page 47722]]

characterize source water pathogen levels and capture a degree of
annual variability. To expedite the date by which systems will provide
additional treatment where high risk source waters are identified,
large system Cryptosporidium monitoring will begin six months after
promulgation of the LT2ESWTR. Upon completion of Cryptosporidium
monitoring, systems will have six months to work with their primacy
agency to determine their bin classification. Beginning at this point,
which is three years following LT2ESWTR promulgation, large systems
will have three years to implement the treatment processes or control
strategies necessary to comply with any additional treatment
requirements stemming from bin classification.
Other large system compliance dates in areas like approval of
grandfathered monitoring data, disinfection profiling and benchmarking,
and reporting deadlines associated with microbial toolbox components
all stem from the Cryptosporidium monitoring and treatment compliance
schedule.
With respect to small systems under the LT2ESWTR, EPA is proposing
that small systems first monitor for E. coli as a screening analysis in
order to reduce the number of small systems that incur the cost of
Cryptosporidium monitoring. However, due to limitations in available
data, the Agency has determined that it is necessary to use data
generated by large systems under the LT2ESWTR to confirm or refine the
E. coli indicator criteria that will trigger small system
Cryptosporidium monitoring. Consequently, small system indicator
monitoring will begin at the conclusion of large system monitoring.
This approach was recommended by the Advisory Committee.
Accordingly, small systems will monitor for E. coli for one year,
beginning 30 months after LT2ESWTR promulgation. Following this, small
systems will have six months to determine if they are required to
monitor for Cryptosporidium and, if so, contract with an approved
analytical laboratory. Cryptosporidium monitoring by small systems will
be conducted for one year, which, when added to the one year of E. coli
monitoring, equals two years of source water monitoring. This is
equivalent to the time period large systems spend in source water
monitoring.
The time periods associated with bin assignment and compliance with
additional treatment requirements for small systems are the same as
those proposed for large systems. Specifically, small systems will have
six months to work with their States to determine their bin
classification following the conclusion of Cryptosporidium sampling.
From this point, which is 5.5 years after LT2ESWTR promulgation, small
systems have three years to meet any additional treatment requirements
resulting from bin classification. States can grant additional time to
small systems for compliance with treatment technique requirements
through granting exemptions (see SDWA section 1416).
3. Request for Comments
EPA requests comments on the treatment technique compliance
schedules for large and small systems in today's proposal, including
the following issues:
Time Window Between Large and Small System Monitoring
Under the current proposal, small filtered system E. coli
monitoring begins in the month following the end of large system
Cryptosporidium, E. coli, and turbidity monitoring. EPA plans to
evaluate large system monitoring results on an ongoing basis as the
data are reported to determine if any refinements to the E. coli levels
that trigger small system Cryptosporidium monitoring are necessary. If
such refinements were deemed appropriate, EPA would issue guidance to
States, which can establish alternative trigger values for small system
monitoring under the LT2ESWTR.
This implementation schedule does not leave any time between the
end of large system monitoring and the initiation of small system
monitoring. Consequently, if it is necessary to provide guidance on
alternative trigger values prior to when small system monitoring
begins, such guidance would be based on less than the full set of large
system results (e.g., first 18 months of large system data). EPA
requests comment on whether an additional time window between the end
of large system monitoring and the beginning of small system monitoring
is appropriate and, if so, how long such a window should be.
Implementation Schedule for Consecutive Systems
The Stage 2 M-DBP Agreement in Principle (65 FR 83015, December 29,
2000) (USEPA 2000a) continues the principle of simultaneous compliance
to address microbial pathogens and disinfection byproducts. Systems are
generally expected to address LT2ESTWR requirements concurrently with
those of the Stage 2 DBPR (as noted earlier, the Stage 2 DBPR is
scheduled to be proposed later this year and to be promulgated at the
same time as the LT2ESWTR).
As with the LT2ESWTR, small water systems (< 10,000 served)
generally begin monitoring and must be in compliance with the Stage 2
DBPR at a date later than that for large systems. However, the Advisory
Committee recommended that small systems that buy/receive from or sell/
deliver finished water to a large system (that is, they are part of the
same ``combined distribution system'') comply with Stage 2 DBPR
requirements on the same schedule as the largest system in the combined
distribution system. This approach is intended to ensure that systems
consider impacts throughout the combined distribution system when
making compliance decisions (e.g, selecting new technologies or making
operational modifications) and to facilitate all systems meeting the
compliance deadlines for the rule.
The issue of combined distribution systems associated with systems
buying and selling water is expected to be of less significance for the
LT2ESWTR. The requirements of the LT2ESWTR apply to systems treating
raw surface water and generally will not involve compliance steps when
systems purchase treated water. Consequently, the compliance schedule
for today's proposal does not address combined distribution systems.
However, this proposed approach raises the possibility that a small
system treating surface water and selling it to a large system could be
required to take compliance steps at an earlier date under the Stage 2
DBPR than under the LT2ESWTR. While a small system in this situation
could choose to comply with the LT2ESWTR on an earlier schedule, the
two rules would not require simultaneous compliance. EPA requests
comment on how this scenario should be addressed in the LT2ESWTR.

G. Public Notice Requirements

1. What Is EPA Proposing Today?
EPA is proposing that under the LT2ESWTR, a Tier 2 public notice
will be required for violations of additional treatment requirements
and a Tier 3 public notice will be required for violations of
monitoring and testing requirements. Where systems violate LT2ESWTR
treatment requirements, today's proposal requires the use of the
existing health effects language for microbiological contaminant
treatment technique violations, as stated in 40 CFR 141 Subpart Q,
Appendix B.

[[Page 47723]]

2. How Was This Proposal Developed?
In 2000, EPA published the Public Notification Rule (65 FR 25982,
May 4, 2000) (USEPA 2000d), which revised the general public
notification regulations for public water systems in order to implement
the public notification requirements of the 1996 SDWA amendments. This
regulation established the requirements that public water systems must
follow regarding the form, manner, frequency, and content of a public
notice. Public notification of violations is an integral part of the
public health protection and consumer right-to-know provisions of the
1996 SDWA Amendments.
Owners and operators of public water systems are required to notify
persons served when they fail to comply with the requirements of a
NPDWR, have a variance or exemption from the drinking water
regulations, or are facing other situations posing a risk to public
health. The public notification requirements divide violations into
three categories (Tier 1, Tier 2 and Tier 3) based on the seriousness
of the violations, with each tier having different public notification
requirements.
EPA has limited its list of violations and situations routinely
requiring a Tier 1 notice to those with a significant potential for
serious adverse health effects from short term exposure. Tier 1
violations contain language specified by EPA that concisely and in non-
technical terms conveys to the public the adverse health effects that
may occur as a result of the violation. States and water utilities may
add additional information to each notice, as deemed appropriate for
specific situations. A State may elevate to Tier 1 other violations and
situations with significant potential to have serious adverse health
effects from short-term exposure, as determined by the State.
Tier 2 public notices address other violations with potential to
have serious adverse health effects on human health. Tier 2 notices are
required for the following situations:
[sbull] All violations of the MCL, maximum residual disinfectant
level (MRDL) and treatment technique requirements, except where a Tier
1 notice is required or where the State determines that a Tier 1 notice
is required; and
[sbull] Failure to comply with the terms and conditions of any
existing variance or exemption.
Tier 3 public notices include all other violations and situations
requiring public notice, including the following situations:
[sbull] A monitoring or testing procedure violation, except where a
Tier 1 or 2 notice is already required or where the State has elevated
the notice to Tier 1 or 2; and
[sbull] Operation under a variance or exemption.
The State, at its discretion, may elevate the notice requirement
for specific monitoring or testing procedures from a Tier 3 to a Tier 2
notice, taking into account the potential health impacts and
persistence of the violation.
As part of the IESWTR, EPA established health effects language for
violations of treatment technique requirements for microbiological
contaminants. EPA believes this language, which was developed with
consideration of Cryptosporidium health effects, is appropriate for
violations of additional Cryptosporidium treatment requirements under
the LT2ESWTR.
3. Request for Comment
EPA requests comment on whether the violations of additional
treatment requirements for Cryptosporidium under the LT2ESWTR should
require a Tier 2 public notice and whether the proposed health effects
language is appropriate.

H. Variances and Exemptions

SDWA section 1415 allows States to grant variances from national
primary drinking water regulations under certain conditions; section
1416 establishes the conditions under which States may grant exemptions
to MCL or treatment technique requirements. For the reasons presented
in the following discussion, EPA has determined that systems will not
be eligible for variances or exemptions to the requirements of the
LT2ESWTR.
1. Variances
Section 1415 specifies two provisions under which general variances
to treatment technique requirements may be granted:
(1) A State that has primacy may grant a variance to a system from
any requirement to use a specified treatment technique for a
contaminant if the system demonstrates to the satisfaction of the State
that the treatment technique is not necessary to protect public health
because of the nature of the system's raw water source. EPA may
prescribe monitoring and other requirements as conditions of the
variance (section 1415(a)(1)(B)).
(2) EPA may grant a variance from any treatment technique
requirement upon a showing by any person that an alternative treatment
technique not included in such requirement is at least as efficient in
lowering the level of the contaminant (section 1415(a)(3)).
EPA does not believe the first provision for granting a variance is
applicable to the LT2ESWTR because Cryptosporidium treatment technique
requirements under this rule account for the degree of source water
contamination. Systems initially comply with the LT2ESWTR by conducting
source water monitoring for Cryptosporidium. Filtered systems are
required to provide additional treatment for Cryptosporidium only if
the source water concentration exceeds a level where current treatment
does not provide sufficient protection. All unfiltered systems are
required to provide a baseline of 2 log inactivation of Cryptosporidium
to achieve finished water risk levels comparable to filtered systems;
however, unfiltered systems are required to achieve 3 log inactivation
only if the source water level exceeds 0.01 oocysts/L.
The second provision for granting a variance is not applicable to
the LT2ESWTR because the treatment technique requirements of this rule
specify the degree to which systems must lower their source water
Cryptosporidium level (e.g., 4, 5, and 5.5 log reduction in Bins 2, 3,
and 4, respectively). The LT2ESWTR provides broad flexibility in how
systems achieve the required level of Cryptosporidium reduction, as
shown in the discussion of the microbial toolbox in section VI.C
Moreover, the microbial toolbox contains an option for Demonstration of
Performance, under which States can award treatment credit based on the
demonstrated efficiency of a treatment process in reducing
Cryptosporidium levels. Thus, there is no need for this type of
variance under the LT2ESWTR.
SDWA section 1415(e) describes small system variances, but these
cannot be granted for a treatment technique for a microbial
contaminant. Hence, small system variances are not allowed for the
LT2ESWTR.
2. Exemptions
Under SDWA section 1416(a), a State may exempt any public water
system from a treatment technique requirement upon a finding that (1)
due to compelling factors (which may include economic factors such as
qualification of the system as serving a disadvantaged community), the
system is unable to comply with the requirement or implement measures
to develop an alternative source of water supply; (2) the system was in
operation on the effective date of the treatment technique requirement,
or for a system that was not in operation by that date, no

[[Page 47724]]

reasonable alternative source of drinking water is available to the new
system; (3) the exemption will not result in an unreasonable risk to
health; and (4) management or restructuring changes (or both) cannot
reasonably result in compliance with the Act or improve the quality of
drinking water.
If EPA or the State grants an exemption to a public water system,
it must at the same time prescribe a schedule for compliance (including
increments of progress or measures to develop an alternative source of
water supply) and implementation of appropriate control measures that
the State requires the system to meet while the exemption is in effect.
Under section 1416(b)(2)(A), the schedule shall require compliance as
expeditiously as practicable (to be determined by the State), but no
later than three years after the otherwise applicable compliance date
for the regulations established pursuant to section 1412(b)(10). For
public water systems that do not serve more than a population of 3,300
and that need financial assistance for the necessary improvements, EPA
or the State may renew an exemption for one or more additional two-year
periods, but not to exceed a total of six years.
A public water system shall not be granted an exemption unless it
can establish that: (1) The system cannot meet the standard without
capital improvements that cannot be completed prior to the date
established pursuant to section 1412(b)(10); or (2) in the case of a
system that needs financial assistance for the necessary
implementation, the system has entered into an agreement to obtain
financial assistance pursuant to section 1452 or any other Federal or
state program; or (3) the system has entered into an enforceable
agreement to become part of a regional public water system.
EPA believes that granting an exemption to the Cryptosporidium
treatment requirements of the LT2ESWTR would result in an unreasonable
risk to health. As described in section II.C, Cryptosporidium causes
acute health effects, which may be severe in sensitive subpopulations
and include risk of mortality. Moreover, the additional Cryptosporidium
treatment requirements of the LT2ESWTR are targeted to systems with the
highest degree of risk. Due to these factors, EPA is not proposing to
allow exemptions under the LT2ESWTR.
3. Request for Comment
a. Variances. EPA requests comment on the determination that the
provisions for granting variances are not applicable to the proposed
LT2ESWTR, specifically including Cryptosporidium inactivation
requirements for unfiltered systems.
In theory it would be possible for an unfiltered system to
demonstrate raw water Cryptosporidium levels that were 3 log lower than
the cutoff for bin 1 for filtered systems and, thus, that it may be
providing comparable public health protection without additional
inactivation. However, EPA has determined that in practice it is not
currently economically or technologically feasible for systems to
ascertain the level of Cryptosporidium at this concentration. This is
due to the extremely large number and volume of samples that would be
necessary to make this demonstration with sufficient confidence. Based
on this determination and the Cryptosporidium occurrence data described
in section III.C, EPA is not proposing to allow unfiltered systems to
demonstrate raw water Cryptosporidium levels low enough to avoid
inactivation requirements. EPA requests comment on this approach.
b. Exemptions. EPA requests comment on the determination that
granting an exemption to the Cryptosporidium treatment requirements of
the LT2ESWTR would result in an unreasonable risk to health.

I. Requirements for Systems To Use Qualified Operators

The SWTR established a requirement that each public water system
using a surface water source or a ground water source under the direct
influence of surface water must be operated by qualified personnel who
meet the requirements specified by the State (40 CFR 141.70). The Stage
1 DBPR extended this requirement to include all systems affected by
that rule, and required that States maintain a register of qualified
operators (40 CFR 141.130(c)). While the proposed LT2ESWTR establishes
no new requirements regarding the operation of systems by qualified
personnel, the Agency would like to emphasize the important role that
qualified operators play in delivering safe drinking water to the
public. EPA encourages States that do not already have operator
certification programs in effect to develop such programs. States
should also review and modify, as required, their qualification
standards to take into account new technologies (e.g., ultraviolet
disinfection) and new compliance requirements.

J. System Reporting and Recordkeeping Requirements

1. Overview
Today's proposal includes reporting and recordkeeping requirements
associated with proposed monitoring and treatment requirements. As
described earlier, systems must conduct source water monitoring to
determine a treatment bin classification for filtered systems or a mean
Cryptosporidium level for unfiltered systems. Systems with previously
collected monitoring data may be able to use (i.e., grandfather) those
data in lieu of conducting new monitoring. Following source water
monitoring, systems will be required to comply with any additional
Cryptosporidium treatment requirements by implementing treatment and
control strategies from a microbial toolbox of options. Systems must
conduct a second round of source water monitoring six years after bin
classification.
In addition, systems using uncovered finished water storage
facilities must cover the facility or provide treatment unless the
system implements a State-approved risk management strategy. Certain
systems will be required to conduct disinfection profiling and
benchmarking.
The proposed rule requires public water systems to submit schedules
for Cryptosporidium, E. coli, and turbidity sampling at least 3 months
before monitoring must begin. Source water sample analysis results must
be reported not later than ten days after the end of first month
following the month when the sample is collected. As described later,
large systems (at least 10,000 people served) will report monitoring
results from the initial round of monitoring directly to EPA through an
electronic data system. Small systems will report monitoring results to
the State. Both small and large systems will report monitoring results
from the second round of monitoring to the State.
Systems must report a bin classification (filtered systems) or mean
Cryptosporidium level (unfiltered systems) within six months following
the month when the last sample in a particular round of monitoring is
scheduled to be collected. If systems are required to provide
additional treatment for Cryptosporidium, they must report regarding
the use of microbial toolbox components. Systems must notify the State
within 24 months following promulgation of the rule if they use
uncovered finished water storage facilities. Systems must also make
reports related to disinfection profiling and benchmarking. Reporting

[[Page 47725]]

requirements associated with these activities are summarized in Tables
IV-25 to IV-28.

Table IV-25.-- Summary of Initial Large Filtered System Reporting Requirements
----------------------------------------------------------------------------------------------------------------
You must report the following items On the following schedule
----------------------------------------------------------------------------------------------------------------
Sampling schedule for Cryptosporidium, E. coli, No later than 3 months after promulgation.
and turbidity monitoring.
Results of Cryptosporidium, E. coli, and turbidity No later than 10 days after the end of the first month
analyses. following the month in which the sample is collected.
Bin determination................................. No later than 36 months after promulgation.
Demonstration of compliance with additional Beginning 72 months after promulgation \1\ (See table IV-
treatment requirements. 34).
Disinfection profiling component reports.......... See Table IV-35.
----------------------------------------------------------------------------------------------------------------
\1\ States may grant an additional two years for systems making capital improvements.

Table IV-26.--Summary of Initial Small Filtered System Reporting Requirements
----------------------------------------------------------------------------------------------------------------
You must report the following items On the following schedule
----------------------------------------------------------------------------------------------------------------
Sampling schedule for E. coli monitoring.......... No later than 27 months after promulgation.
Results of E. coli analyses (unless State approves No later than 10 days after the end of the first month
a different indicator). following the month in which the sample was collected.
Mean E. coli concentration (unless State approves No later than 45 months after promulgation.
a different indicator).
Disinfection profiling component reports.......... See Table IV-36.
---------------------------------------------------
Additional requirements if E. coli trigger level is exceeded \1\
----------------------------------------------------------------------------------------------------------------
Sampling schedule for Cryptosporidium monitoring.. No later than 45 months after promulgation.
Results of Cryptosporidium analyses............... No later than 10 days after the end of the first month
following the month in which the sample is collected.
Bin determination................................. No later than 66 months after promulgation.
Demonstration of compliance with additional Beginning 102 months after promulgation \2\ (See Table IV-
treatment requirements. 34).
----------------------------------------------------------------------------------------------------------------
\1\ If the E. coli annual mean concentration exceeds 10/100 mL for systems using lakes/reservoirs or exceeds 50/
100 mL for systems using flowing streams, then systems must conduct Cryptosporidium monitoring. States may
approve alternative indicator criteria to trigger Cryptosporidium monitoring.
\2\ States may grant an additional two years for systems making capital improvements.

Table IV-27.--Summary of Initial Large Unfiltered System Reporting Requirements
----------------------------------------------------------------------------------------------------------------
You must report the following items On the following schedule
----------------------------------------------------------------------------------------------------------------
Cryptosporidium sampling schedule................. No later than 3 months after promulgation.
Results of Cryptosporidium analyses............... No later than 10 days after the end of the first month
following the month in which the sample was collected.
Determination of mean Cryptosporidium No later than 36 months after promulgation.
concentration.
Disinfection profiling component reports.......... See Table IV-35.
Demonstration of compliance with Cryptosporidium Beginning 72 months after promulgation \1\ (see Table IV-
inactivation requirements. 34).
----------------------------------------------------------------------------------------------------------------
\1\ States may grant an additional two years for systems making capital improvements.

Table IV-28.--Summary of Initial Small Unfiltered System Reporting Requirements
----------------------------------------------------------------------------------------------------------------
You must report the following items On the following schedule
----------------------------------------------------------------------------------------------------------------
Cryptosporidium sampling schedule................. No later than 45 months after promulgation.
Results of Cryptosporidium analyses............... No later than 10 days after the end of the first month
following the month in which the sample was collected.
Determination of mean Cryptosporidium No later than 66 months after promulgation.
concentration.
Disinfection profiling component reports.......... See Table IV-35.
Demonstration of compliance with Cryptosporidium Beginning 102 months after promulgation \1\ (see Table IV-
inactivation requirements. 34).
----------------------------------------------------------------------------------------------------------------
\1\ States may grant an additional two years for systems making capital improvements.

[[Page 47726]]

2. Reporting Requirements for Source Water Monitoring
a. Data elements to be reported. Proposed reporting requirements
for LT2ESWTR monitoring stem from proposed analytical method
requirements. As stated in sections IV.K and IV.L, systems must have
Cryptosporidium analyses conducted by EPA-approved laboratories using
Methods 1622 or 1623. E. coli analyses must be performed by State-
approved laboratories using the E. coli methods proposed for approval
in section IV.K. Systems are required to report the data elements
specified in Table IV-29 for each Cryptosporidium analysis. To comply
with LT2ESWTR requirements, only the sample volume filtered and the
number of oocysts counted must be reported for samples in which at
least 10 L is filtered and all of the sample volume is analyzed.
Additional information is required for samples where the laboratory
analyzes less than 10 L or less than the full sample volume collected.
Table IV-30 presents the data elements that systems must report for E.
coli analyses.
As described in the following section, EPA is developing a data
system to manage and analyze the microbial monitoring data that will be
reported by large systems under the LT2ESWTR. EPA is exploring
approaches for application of this data system to support small system
data reporting as well. Systems, or laboratories acting as the systems'
agents, must keep Method 1622/1623 bench sheets and slide examination
report forms until 36 months after an equivalent round of source water
monitoring has been completed (e.g., second round of Cryptosporidium
monitoring).

Table IV-29.--Proposed Cryptosporidium Data Elements to be Reported
----------------------------------------------------------------------------------------------------------------
Data element Reason for data element
----------------------------------------------------------------------------------------------------------------
Identifying information
----------------------------------------------------------------------------------------------------------------
[sbull] PWSID................................ Needed to associate plant with public water system.
[sbull] Facility ID.......................... Needed to associate sample result with facility.
[sbull] Sample collection point.............. Needed to associate sample result with sampling point.
[sbull] Sample collection date............... Needed to determine that utilities are collecting samples at the
frequency required.
[sbull] Sample type (field or matrix spike) Needed to distinguish field samples from matrix samples for
\1\. recovery calculations.
----------------------------------------------
Sample results
----------------------------------------------------------------------------------------------------------------
[sbull] Sample volume filtered (L), to Needed to verify compliance with sample volume requirements.
nearest \1/4\ L \2\.
[sbull] Was 100% of filtered volume examined? Needed to calculate the final concentration of oocysts/L and
\3\. determine if volume analyzed requirements are met.
[sbull] Number of oocysts counted............ Needed to calculate the final concentration of oocysts/L.
----------------------------------------------------------------------------------------------------------------
\1\ For matrix spike samples, sample volume spiked and estimated number of oocysts spiked must be reported.
These data are not required for field samples.
\2\ For samples in which <10 L is filtered or <100% of the sample volume is examined, the number of filters used
and the packed pellet volume must also be reported to verify compliance with LT2ESWTR sample volume analysis
requirements. These data are not required for most samples.
\3\ For samples in which <100% of sample is examined, the volume of resuspended concentrate and volume of this
resuspension processed through IMS must be reported to calculate the sample volume examined. These data will
not be required for most samples.

Table IV-30.--Proposed E. coli Data Elements to be Reported
----------------------------------------------------------------------------------------------------------------
Data element Reason for collecting data element
----------------------------------------------------------------------------------------------------------------
Identifying Information
----------------------------------------------------------------------------------------------------------------
PWS ID...................................... Needed to associate analytical result with public water system.
Facility ID................................. Needed to associate plant with public water system.
Sample collection point..................... Needed to associate sample result with sampling point.
Sample collection date...................... Needed to determine that utilities are collecting samples at the
frequency required.
Analytical method number.................... Needed to associate analytical result with analytical method.
Method Type................................. Needed to verify that an approved method was used and call up
correct web entry form.
Source water type........................... Needed to assess Cryptosporidium indicator relationships.
E. coli/100 mL.............................. Sample result (although not required, the laboratory also will
have the option of entering primary measurements for a sample
into the LT2ESWTR internet-based database to have the database
automatically calculate the sample result).
---------------------------------------------
Turbidity Information
----------------------------------------------------------------------------------------------------------------
Turbidity result............................ Needed to assess Cryptosporidium indicator relationships.
----------------------------------------------------------------------------------------------------------------

b. Data system. Because source water monitoring by large systems
(serving at least 10,000 people) will begin 6 months following
promulgation of the LT2ESWTR, EPA expects to act as the primacy agency
with oversight responsibility for large system sampling, analysis, and
data reporting. To facilitate collection and analysis of large system
monitoring data, EPA is developing an Internet-based electronic data
collection and management system. This approach is similar to that used
under the Unregulated Contaminants Monitoring Rule (UCMR) (64 FR 50556,
September 17, 1999) (USEPA 1999c).
Analytical results for Cryptosporidium, E. coli, and turbidity
analyses will be reported directly to this database using web forms and
software that can be downloaded free of charge.

[[Page 47727]]

The data system will perform logic checks on data entered and calculate
final results from primary data (where necessary). This is intended to
reduce reporting errors and limit the time involved in investigating,
checking, and correcting errors at all levels. EPA will make large
system monitoring data available to States when States assume primacy
for the LT2ESWTR or earlier under State agreements with EPA.
Large systems should instruct their laboratories to electronically
enter monitoring results into the EPA data system using web-based
manual entry forms or by uploading XML files from laboratory
information management systems (LIMS). After data are submitted by a
laboratory, systems may review the results on-line. If a system
believes that a result was entered into the data system erroneously,
the system may notify the laboratory to rectify the entry. In addition,
if a system believes that a result is incorrect, the system may submit
the result as a contested result and petition EPA or the State to
invalidate the sample. If a system contests a sample result, the system
must submit a rationale to the primacy agency, including a supporting
statement from the laboratory, providing a justification. Systems may
arrange with laboratories to review their sample results prior to the
results being entered into the EPA data system. Also, if a system
determines that its laboratory does not have the capability to report
data electronically, the system can submit a request to EPA to use an
alternate reporting format.
Regardless of the reporting process used, systems are required to
report an analytical monitoring result to the primacy agency no later
than 10 days after the end of the first month following the month when
the sample was collected. As described in section IV.A.1, if a system
is unable to report a valid Cryptosporidium analytical result for a
scheduled sampling date due to failure to comply with the analytical
method requirements (e.g., violation of quality control requirements),
the system must collect a replacement sample within 14 days of being
notified by the laboratory or the State that a result cannot be
reported for that date and must submit an explanation for the
replacement sample with the analytical results. A system will not incur
a monitoring violation if the State determines that the failure to
report a valid analysis result was due to circumstances beyond the
control of the system. However, in all cases the system must collect a
replacement sample.
The data elements to be collected by the electronic data system
will enhance the reliability of the microbial data generated under the
LT2ESWTR, while reducing the burden on the analytical laboratories and
public water systems. Tables IV-31 and IV-32 summarize the system's
data analysis functions for Cryptosporidium measurements.

Table IV-31.-- LT2ESWTR Data System Functions for Cryptosporidium Data
----------------------------------------------------------------------------------------------------------------
Applicability to sample types
Value calculated Formula -----------------------------------
Field Matrix spike
----------------------------------------------------------------------------------------------------------------
Calculation of sample volume (Volume filtered) * (resuspended Yes............. Yes.
analyzed. concentrate volume transferred to IMS/
resuspended concentrate volume).
Pellet volume analyzed......... (pellet volume)*(resuspended concentrated Yes............. Yes.
volume transferred to IMS/resuspended
concentrate volume).
Calculation of oocysts/L....... (Number of oocysts counted)/(sample volume Yes............. Yes.
analyzed).
Calculation of estimated number (Number of oocysts spiked)/(sample volume No.............. Yes.
of oocysts spiked/L. spiked).
Calculation of percent ((Calculated of oocysts/L for the No.............. Yes.
recoveries for MS samples. MS sample)--(Calculated of
oocysts/L in the associated field sample))
/ (Estimated number of oocysts spiked/L) *
100%.
----------------------------------------------------------------------------------------------------------------

Table IV-32.--LT2ESWTR Data System Functions for Cryptosporidium
Compliance Checks
------------------------------------------------------------------------
LT2 requirements Description
------------------------------------------------------------------------
Sample volume analysis....... Specifies that the LT2 requirements for
sample volume analyzed were met when:
[sbull] volume analyzed is 10
L.
[sbull] volume analyzed is < 10 L and
pellet volume analyzed is at least 2 mL.
[sbull] volume analyzed < 10 L and pellet
volume analyzed < 2 mL and 100% of
filtered volume examined= Y and two
filters were used.
Specifies that the LT2 requirements for
sample volume analyzed were not met
when:
[sbull] volume analyzed < 10 L and pellet
volume analyzed is < 2 mL and 100% of
filtered volume examined= N.
[sbull] volume analyzed is < 10 L and
pellet volume analyzed < 2 mL and only 1
filter used.
Schedule met................. Specifies that the predetermined sampling
schedule is met when the sample
collection data is within +/- 2 days of
the scheduled date.
------------------------------------------------------------------------

c. Previously collected monitoring data. Table IV-33 provides a
summary of the items that systems must report to EPA for consideration
of previously collected (grandfathered) monitoring data under the
LT2ESWTR. For each field and matrix spike (MS) sample, systems must
report the data elements specified in Table IV-29. In addition, the
laboratory that analyzed the samples must submit a letter certifying
that all Method 1622 and 1623 quality control requirements (including
ongoing precision and recovery (OPR) and method blank (MB) results,
holding times, and positive and negative staining controls) were
performed at the required frequency and were acceptable. Alternatively,
the laboratory may provide for each field, MS, OPR, and MB sample a
bench sheet and sample examination report form (Method 1622 and 1623
bench sheets are shown in USEPA 2003h).
Systems must report all routine source water Cryptosporidium
monitoring results collected during the

[[Page 47728]]

period covered by the previously collected data that have been
submitted. This applies to all samples that were collected from the
sampling location used for monitoring, not spiked, and analyzed using
the laboratory's routine process for Method 1622 or 1623 analyses,
including analytical technique and QA/QC. Other requirements associated
with use of previously collected data are specified in section
IV.A.1.d. Where applicable, systems must provide documentation
addressing the dates and reason(s) for re-sampling, as well as the use
of presedimentation, off-stream storage, or bank filtration during
monitoring. Review of the submitted information, along with the results
of the quality assurance audits of the laboratory that produced the
data, will be used to determine whether the data meet the requirements
for grandfathering.

Table IV-33.--Items That Must Be Reported for Consideration of Grandfathered Monitoring Data
----------------------------------------------------------------------------------------------------------------
The following items must be reported \1\ On the following schedule \1\
----------------------------------------------------------------------------------------------------------------
Data elements listed in Table IV-29 for each field and MS No later than 2 months after promulgation if
sample. the system does not intend to conduct new
monitoring under the LT2ESWTR.
Letter from laboratory certifying that method-specified QC was
performed at required frequency and was acceptable.
OR OR
Method 1622/1623 bench sheet and sample examination report form No later than 8 months after promulgation if
for each field, MS, OPR, and method blank sample. the system intends to conduct new monitoring
under the LT2ESWTR.
Letter from system certifying (1) that all source water data ...............................................
collected during the time period covered by the previously
collected data have been submitted and (2) that the data
represent the plant's current source water.
Where applicable, documentation addressing the dates and ...............................................
reason(s) for re-sampling, as well as the use of
presedimentation, off-stream storage, or bank filtration
during monitoring.
----------------------------------------------------------------------------------------------------------------
\1\ See section IV.A.1. for details.

3. Compliance With Additional Treatment Requirements
Under the proposed LT2ESWTR, systems may choose from a ``toolbox''
of management and treatment options to meet their additional
Cryptosporidium treatment requirements. In order to receive credit for
toolbox components, systems must initially demonstrate that they comply
with any required design and implementation criteria, including
performance validation testing. Additionally, systems must provide
monthly verification of compliance with any required operational
criteria, as shown through ongoing monitoring. Required design,
implementation, operational, and monitoring criteria for toolbox
components are described in section IV.C. Proposed reporting
requirements associated with these criteria are shown in Table IV-34
for both large and small systems.

Table IV-34.--Toolbox Reporting Requirements
----------------------------------------------------------------------------------------------------------------
On the following
Toolbox option (potential schedule \1\ On the following
Cryptosporidium reduction log You must submit the following items (systems serving =10,000 (systems serving
people) < 10,000 people)
----------------------------------------------------------------------------------------------------------------
Watershed Control Program (WCP) Notify State of intention to develop No later than 48 No later than 78
(0.5 log) WCP. months after months after
Submit initial WCP plan to State...... promulgation promulgation.
No later than 60 No later than 90
months after months after
promulgation. promulgation.
Annual program status report and State- By a date determined By a date
approved watershed survey report. by the State, every determined by
12 months, the State, every
beginning 84 months 12 months,
after promulgation beginning 114
months after
promulgation.
Request for re-approval and report on No later than 6 No later than 6
the previous approval period. months prior to the months prior to
end of the current the end of the
approval period or current approval
by a date period or by a
previously date previously
determined by the determined by
State the State.
Pre-sedimentation (0.5 log) Monthly verification of: Monthly reporting Monthly reporting
(new basins) Continuous basin operation............ within 10 days within 10 days
Treatment of 100% of the flow......... following the month following the
Continuous addition of a coagulant.... in which the month in which
At least 0.5 log removal of influent monitoring was the monitoring
turbidity based on the monthly mean conducted, was conducted,
of daily turbidity readings for 11 of beginning 72 months beginning 102
the 12 previous months. after promulgation months after
promulgation.
Two-Stage Lime Softening (0.5 Monthly verification of: No later than 72 No later than 102
log) Continuous operation of a second months after months after
clarification step between the promulgation promulgation.
primary clarifier and filter.
Presence of coagulant (may be lime) in
first and second stage clarifiers.
Both clarifiers treat 100% of the
plant flow.

[[Page 47729]]

Bank filtration (0.5 or 1.0 Initial demonstration of: Initial Initial
log) (new) Unconsolidated, predominantly sandy demonstration no demonstration no
aquifer. later than 72 later than 102
Setback distance of at least 25 ft. months after months after
(0.5 log) or 50 ft. (1.0 log). promulgation promulgation.
If monthly average of daily max Report within 30 Report within 30
turbidity is greater than 1 NTU then days following the days following
system must report result and submit month in which the the month in
an assessment of the cause monitoring was which the
conducted, monitoring was
beginning 72 months conducted,
after promulgation beginning 102
months after
promulgation.
Combined filter performance Monthly verification of: Monthly reporting Monthly
(0.5 log) Combined filter effluent (CFE) within 10 days reporting:
turbidity levels less than or equal following the month within 10 days
to 0.15 NTU in at least 95 percent of in which the following the
the 4 hour CFE measurements taken monitoring was month in which
each month. conducted, the monitoring
beginning on 72 was conducted,
months after beginning on 102
promulgation months after
promulgation.
Membranes (MF, UF, NF, RO) (2.5 Initial demonstration of: No later than 72 No later than 102
log or greater based on Removal efficiency through challenge months after months after
verification/integrity studies. promulgation promulgation.
testing) Methods of challenge studies meet rule
criteria.
Integrity test results and baseline...
Monthly report summarizing: Within 10 days Within 10 days
All direct integrity test results following the month following the
above the control limit and the in which monitoring month in which
corrective action that was taken. was conducted, monitoring was
All indirect integrity monitoring beginning 72 months conducted,
results triggering direct integrity after promulgation beginning 102
testing and the corrective action months after
that was taken. promulgation.
Bag filters (1.0 log) and Initial demonstration that the No later than 72 No later than 102
Cartridge filters (2.0 log) following criteria are met: months after months after
Process meets the basic definition of promulgation promulgation.
bag or cartridge filtration;.
Removal efficiency established through
challenge testing that meets rule
criteria.
Challenge test shows at least 2 and 3
log removal for bag and cartridge
filters, respectively.
Chlorine dioxide (log credit Summary of CT values for each day and Within 10 days Within 10 days
based on CT) log inactivation based on tables in following the month following the
section IV.C.14 in which monitoring month in which
was conducted, monitoring was
beginning 72 months conducted,
after promulgation beginning 102
months after
promulgation.
Ozone (log credit based on CT) Summary of CT values for each day and Within 10 days Within 10 days
log inactivation based on tables in following the month following the
section IV.C.14 in which monitoring month in which
was conducted, monitoring was
beginning 72 months conducted,
after promulgation beginning 102
months after
promulgation.
UV (log credit based UV dose Results from reactor validation No later than 72 No later than 102
and operating within validated testing demonstrating operating months after months after
conditions) conditions that achieve required UV promulgation promulgation.
dose
Monthly report summarizing the Within 10 days Within 10 days
percentage of water entering the following the month following the
distribution system that was not in which monitoring month in which
treated by UV reactors operating was conducted, monitoring was
within validated conditions for the beginning 72 months conducted,
required UV dose in section IV.C.15 after promulgation beginning 102
months after
promulgation.
Individual filter performance Monthly verification of the following, Monthly reporting Monthly
(1.0 log) based on continuous monitoring of within 10 days reporting:
turbidity for each individual filter: following the month within 10 days
Filtered water turbidity less than 0.1 in which the following the
NTU in at least 95 percent of the monitoring was month in which
daily maximum values from individual conducted, the monitoring
filters (excluding 15 minute period beginning on 72 was conducted,
following start up after backwashes). months after beginning 102
No individual filter with a measured promulgation months after
turbidity greater than 0.3 NTU in two promulgation.
consecutive measurements taken 15
minutes apart.
Demonstration of Performance Results from testing following State No later than 72 No later than 102
approved protocol. months after months after
promulgation promulgation.

[[Page 47730]]

Monthly verification of operation Within 10 days Within 10 days
within State-approved conditions for following the month following the
demonstration of performance credit in which monitoring month in which
was conducted, monitoring was
beginning 72 months conducted,
after promulgation beginning 102
months after
promulgation.
----------------------------------------------------------------------------------------------------------------
\1\ States may allow an additional two years for systems making capital improvements.

Reporting requirements associated with disinfection profiling and
benchmarking are summarized in Table IV-35 for large systems and in
Table IV-36 for small systems.

Table IV-35.--Disinfection Benchmarking Reporting Requirements for Large Systems
----------------------------------------------------------------------------------------------------------------
Submit the following On the following
System type Benchmark component items schedule
----------------------------------------------------------------------------------------------------------------
Systems required to conduct Characterization of Giardia lamblia and No later than 36
Cryptosporidium monitoring. Disinfection Practices. virus inactivation months after
profiles must be on promulgation.
file for State review
during sanitary
survey.
State Review of Proposed Inactivation profiles Prior to significant
Changes to Disinfection and benchmark modification of
Practices. determinations. disinfection
practice.
Systems not required to conduct Applicability.............. None.................. None.
Cryptosporidium monitoring\1\.
Characterization of None.................. None.
Disinfection Practices.
State Review of Proposed None.................. None.
Changes to Disinfection
Practices.
----------------------------------------------------------------------------------------------------------------
\1\Systems that provide at least 5.5 log of Cryptosporidium treatment consistent with a Bin 4 treatment
implication are not required to conduct Cryptosporidium monitoring.

Table IV-36.--Disinfection Benchmarking Reporting Requirements for Small Systems
----------------------------------------------------------------------------------------------------------------
Submit the following On the following
System type Benchmark component items schedule
----------------------------------------------------------------------------------------------------------------
Systems required to conduct Characterization of Giardia lamblia and No later than 66
Cryptosporidium monitoring. Disinfection Practices. virus inactivation months after
profiles must be on promulgation.
file for State review
during sanitary
survey.
State Review of Proposed Inactivation profiles Prior to significant
Changes to Disinfection and benchmark modification of
Practices. determinations. disinfection
practice.
Systems not required to conduct Applicability Period....... Notify State that No later than 42
Cryptosporidium monitoring and profiling is required months after
that exceed DBP triggers\1,2,3\. based on DBP levels. promulgation.
Characterization of Giardia lamblia and No later than 54
Disinfection Practices. virus inactivation months after
profiles must be on promulgation.
file for State review
during sanitary
survey.
State Review of Proposed Inactivation profiles Prior to significant
Changes to Disinfection and benchmark modification of
Practices. determinations. disinfection
practice.
Systems not required to conduct Applicability Period....... Notify State that No later than 42
Cryptosporidium monitoring and profiling is not months after
that do not exceed DBP required based on DBP promulgation.
triggers\2,3\. levels.
Characterization of None.................. None.
Disinfection Practices.
State Review of Proposed None.................. None.
Changes to Disinfection
Practices.
----------------------------------------------------------------------------------------------------------------
\1\ Systems that provide at least 5.5 log of Cryptosporidium treatment consistent with a Bin 4 treatment
implication are not required to conduct Cryptosporidium monitoring.
\2\ If the E. coli annual mean concentration is <= 10/100 mL for systems using lakes/reservoir sources or <= 50/
100 mL for systems using flowing stream sources, the system is not required to conduct Cryptosporidium
monitoring and will only be required to characterize disinfection practices if DBP triggers are exceeded.

[[Page 47731]]

\3\ If the system is a CWS or NTNCWSs and TTHM or HAA5 levels in the distribution system are at least 0.064 mg/L
or 0.048 mg/L, respectively, calculated as an LRAA at any Stage 1 DBPR sampling site, then the system is
triggered into disinfection profiling.

4. Request for Comment
EPA requests comment on the reporting and recordkeeping
requirements proposed for the LT2ESWTR.
Specifically, the Agency requests comment on the proposed
requirement that systems report monthly on the use of microbial toolbox
components to demonstrate compliance with their Cryptosporidium
treatment requirements. An alternative may be for systems to keep
records on site for State review instead of reporting the data.

K. Analytical Methods

EPA is proposing to require public water systems to conduct
LT2ESWTR monitoring using approved methods for Cryptosporidium, E.
coli, and turbidity analyses. This includes meeting quality control
criteria stipulated by the approved methods and additional method-
specific requirements, as stated later in this section. Related
requirements on the use of approved laboratories are discussed in
section IV.L, and proposed requirements for reporting of data were
stated previously in section IV.J. EPA has developed draft guidance for
sampling and analyses under the LT2ESWTR (see USEPA 2003g and 2003h).
This guidance is available in draft form in the docket for today's
proposal (http://www.epa.gov/edocket/).
1. Cryptosporidium
a. What is EPA proposing today? Method 1622: ``Cryptosporidium in
Water by Filtration/IMS/FA'' (EPA-821-R-01-026, April 2001) (USEPA
2001e) and Method 1623: ``Cryptosporidium and Giardia in Water by
Filtration/IMS/FA'' (EPA 821-R-01-025, April 2001) (USEPA 2001f) are
proposed for Cryptosporidium analysis under this rule. Methods 1622 and
1623 require filtration, immunomagnetic separation (IMS) of the oocysts
from the captured material, and examination based on IFA, DAPI staining
results, and differential interference contrast (DIC) microscopy for
determination of oocyst concentrations.
Method Requirements
For each Cryptosporidium sample under this proposal, all systems
must analyze at least a 10-L sample volume. Systems may collect and
analyze greater than a 10-L sample volume. If a sample is very turbid,
it may generate a large packed pellet volume upon centrifugation (a
packed pellet refers to the concentrated sample after centrifugation
has been performed in EPA Methods 1622 and 1623). Based on IMS
purification limitations, samples resulting in large packed pellets
will require that the sample concentrate be aliquoted into multiple
``subsamples'' for independent processing through IMS, staining, and
examination. Because of the expense of the IMS reagents and analyst
time to examine multiple slides per sample, systems are not required to
analyze more than 2 mL of packed pellet volume per sample.
In cases where it is not feasible for a system to process a 10-L
sample for Cryptosporidium analysis (e.g., filter clogs prior to
filtration of 10 L) the system must analyze as much sample volume as
can be filtered by 2 filters, up to a packed pellet volume of 2 mL.
This condition applies only to filters that have been approved by EPA
for nationwide use with Methods 1622 and 1623--the Pall Gelman
Envirochek^TM and Envirochek^TM HV filters, the
IDEXX Filta-Max^TM foam filter, and the Whatman
CrypTest^TM cartridge filter.
Methods 1622 and 1623 include fluorescein isothiocyanate (FITC) as
the primary antibody stain for Cryptosporidium detection, DAPI staining
to detect nuclei, and DIC to detect internal structures. For purposes
of the LT2ESWTR, systems must report total Cryptosporidium oocysts as
detected by FITC as determined by the color (apple green or alternative
stain color approved for the laboratory under the Lab QA Program
described in section VI.L), size (4-6 [mu]m) and shape (round to oval).
This total includes all of the oocysts identified as described here,
less atypical organisms identified by FITC, DIC, or DAPI (e.g.,
possessing spikes, stalks, appendages, pores, one or two large nuclei
filling the cell, red fluorescing chloroplasts, crystals, spores,
etc.).
Matrix Spike Samples
As required by Method 1622 and 1623, systems must have 1 matrix
spike (MS) sample analyzed for each 20 source water samples. The volume
of the MS sample must be within ten percent of the volume of the
unspiked sample that is collected at the same time, and the samples
must be collected by splitting the sample stream or collecting the
samples sequentially. The MS sample and the associated unspiked sample
must be analyzed by the same procedure. MS samples must be spiked and
filtered in the laboratory. However, if the volume of the MS sample is
greater than 10 L, the system is permitted to filter all but 10 L of
the MS sample in the field, and ship the filtered sample and the
remaining 10 L of source water to the laboratory. In this case, the
laboratory must spike the remaining 10 L of water and filter it through
the filter used to collect the balance of the sample in the field.
EPA is proposing to require the use of flow cytometer-counted
spiking suspensions for spiked QC samples during the LT2ESWTR. This
provision is based on the improved precision expected for spiking
suspensions counted with a flow cytometer, as compared to those counted
using well slides or hemacytometers. During the Information Collection
Rule Supplemental Surveys, the mean relative standard deviation (RSD)
across 25 batches of flow cytometer-sorted Cryptosporidium spiking
suspensions was 1.8%, with a median of 1.7% (Connell et al. 2000). In
EPA Performance Evaluation (PE) studies, the mean RSD for flow
cytometer sorted Cryptosporidium spiking suspensions was 3.4%. In
comparison, the mean RSD for Cryptosporidium spiking suspensions
enumerated manually by 20 laboratories using well slides or
hemacytometers was 17% across 108 rounds of 10-replicate counts.
QC requirements in Methods 1622 and 1623 must be met by
laboratories analyzing Cryptosporidium samples under the LT2ESWTR. The
QC acceptance criteria are the same as stipulated in the method. For
the initial precision and recovery (IPR) test, the mean Cryptosporidium
recovery must be 24% to 100% with maximum relative standard deviation
(i.e., precision) of 55%. For each ongoing precision and recovery (OPR)
sample, recovery must be in the range of 11% to 100%. For each method
blank, oocysts must be undetected.
Methods 1622 and 1623 are performance-based methods and, therefore,
allow multiple options to perform the sample processing steps in the
methods if a laboratory can meet applicable QC criteria and uses the
same determinative technique. If a laboratory uses the same procedures
for all samples, then all field samples and QC samples must be analyzed
in that same manner. However, if a laboratory uses more than one set of
procedures for Cryptosporidium analyses under LT2ESWTR then the
laboratory must analyze separate QC samples for each

[[Page 47732]]

option to verify compliance with the QC criteria. For example, if the
laboratory analyzes samples using both the Envirochek^TM and
Filta-Max^TM filters, a separate set of IPR, OPR, method
blank, and MS samples must be analyzed for each filtration option.
b. How was this proposal developed? EPA is proposing EPA Methods
1622 and 1623 for Cryptosporidium analyses under the LT2ESWTR because
these are the best available methods that have undergone full
validation testing. In addition, these methods have been used
successfully in a national source water monitoring program as part of
the Information Collection Rule Supplemental Surveys (ICRSS). The
minimum sample volume and other quality control requirements are
intended to ensure that data are of sufficient quality to assign
systems to LT2ESWTR risk bins. Further, the proposed method
requirements for analysis of Cryptosporidium are consistent with
recommendations by the Stage 2 M-DBP Advisory Committee. In the
Agreement in Principle, the Committee recommended that source water
Cryptosporidium monitoring under the LT2ESWTR be conducted using EPA
Methods 1622 and 1623 with no less than 10 L samples. EPA also has
proposed these methods for approval for ambient water monitoring under
Guidelines Establishing Test Procedures for the Analysis of Pollutants;
Analytical Methods for Biological Pollutants in Ambient Water (66 FR
45811, August 30, 2001) (USEPA 2001i).
When considering the method performance that could be achieved for
analysis of Cryptosporidium under the LT2ESWTR, EPA and the Advisory
Committee evaluated the Cryptosporidium recoveries reported for Methods
1622 and 1623 in the ICRSS. As described in section III.C, the ICRSS
was a national monitoring program that involved 87 utilities sampling
twice per month over 1 year for Cryptosporidium and other
microorganisms and water quality parameters. During the ICRSS, the mean
recovery and relative standard deviation associated with enumeration of
MS samples for total oocysts by Methods 1622 and 1623 were 43% and 47%,
respectively (Connell et al. 2000).
EPA believes that with provisions like the Laboratory QA Program
for Cryptosporidium laboratories (see section IV.L), comparable
performance to that observed in the ICRSS can be achieved in LT2ESWTR
monitoring with the use of Methods 1622 and 1623, and that this level
of performance will be sufficient to realize the public health goals
intended by EPA and the Advisory Committee for the LT2ESWTR. Other
methods would need to achieve comparable performance to be considered
for use under the LT2ESWTR. For example, EPA does not expect the
Information Collection Rule Method, which resulted in 12% mean recovery
for MS samples during the Information Collection Rule Laboratory
Spiking Program (Scheller, 2002), to meet LT2ESWTR data quality
objectives.
For systems collecting samples larger than 10 L, EPA is proposing
the approach of allowing systems to filter all but 10 L of the
corresponding MS sample in the field, and ship the filtered sample and
the remaining 10 L of source water to the laboratory for spiking and
analysis. The Agency has determined that the added costs associated
with shipping entire high-volume (e.g. 50-L) samples to a laboratory
for spiking and analysis are not merited by improved data quality
relative to the use of Cryptosporidium MS data under the LT2ESWTR. EPA
estimates that the average cost for shipping a 50-L bulk water sample
is $350 more than the cost of shipping a 10-L sample and a filter. A
study comparing these two approaches (i.e., spiking and filtering 50 L
vs. field filtering 40 L and spiking 10 L) indicated that spiking the
10-L sample produced somewhat higher recoveries (USEPA 2003i). However,
the differences were not significant enough to offset the greatly
increased shipping costs, given the limited use of MS data in LT2ESWTR
monitoring.
c. Request for comment. EPA requests comment on the proposed method
requirements for Cryptosporidium analysis, including the following
specific issues:
Minimum Sample Volume
It is the intent of EPA that LT2ESWTR sampling provide
representative annual mean source water concentrations. If systems were
unable to analyze an entire sample volume during certain periods of the
year due to elevated turbidity or other water quality factors, this
could result in systems analyzing different volumes in different
samples. Today's proposal requires systems to analyze at least 10 L of
sample or the maximum amount of sample that can be filtered through two
filters, up to a packed pellet volume of 2 mL. EPA requests comment on
whether these requirements are appropriate for systems with source
waters that are difficult to filter or that generate a large packed
pellet volume. Alternatively, systems could be required to filter and
analyze at least 10 L of sample with no exceptions.
Approval of Updated Versions of EPA Methods 1622 and 1623
EPA has developed draft revised versions of EPA Methods 1622 and
1623 in order to consolidate several method-related changes EPA
believes may be necessary to address LT2ESWTR monitoring requirements
(see USEPA 2003j and USEPA 2003k). EPA is requesting comment on whether
these revised versions should be approved for monitoring under the
LT2ESWTR, rather than the April 2001 versions proposed in today's rule.
If the revised versions were approved, previously collected data
generated using the earlier versions of the methods would still be
acceptable for grandfathering, provided the other criteria described in
section IV.A.1.d were met. Drafts of the updated methods are provided
in the docket for today's rule, and differences between these versions
and the April 2001 versions of the methods are clearly indicated for
evaluation and comment. Changes to the methods include the following:

(1) Increased flexibility in matrix spike (MS) and initial
precision and recovery (IPR) requirements--the requirement that the
laboratory must analyze an MS sample on the first sampling event for
a new PWS would be changed to a recommendation; the revised method
would allow the IPR test to be performed across four different days,
rather than restrict analyses to 1 day;
(2) Clarification of some method procedures, including the
spiking suspension vortexing procedure and the buffer volumes used
during immunomagnetic separation (IMS); requiring (rather than
recommending) that laboratories purchase HCl and NaOH standards at
the normality specified in the method; and clarification that the
use of methanol during slide staining in section 14.2 of the method
is as per manufacturer's instructions;
(3) Additional recommendations for minimizing carry-over of
debris onto microscope slides after IMS and information on
microscope cleaning;
(4) Clarification in the method of the actions to take in the
event of QC failures, such as that any positive sample in a batch
associated with an unacceptable method blank is unacceptable and
that any sample in a batch associated with an unacceptable ongoing
precision and recovery (OPR) sample is unacceptable;
(5) Changes to the sample storage and shipping temperature to
``less than 10[deg]C and not frozen'', and additional guidance on
sample storage and shipping procedures that addresses time of
collection, and includes suggestions for monitoring sample
temperature during shipment and upon receipt at the laboratory.
(6) Additional analyst verification procedures--adding
examination using differential interference contrast (DIC)
microscopy to the analyst verification requirements.

[[Page 47733]]

(7) Addition of an approved method modification using the Pall
Gelman Envirochek HV filter. This approval was based on an
interlaboratory validation study demonstrating that three
laboratories, each analyzing reagent water and a different source
water, met all method acceptance criteria for Cryptosporidium. EPA
issued a letter (dated March 21, 2002) under the Alternative Test
Procedures program approving the procedure as an acceptable version
of Method 1623 for Cryptosporidium (but not for Giardia). EPA also
noted in the letter that the procedure was considered to be an
acceptable modification of EPA Method 1622.
(8) Incorporation of detailed procedures for concentrating
samples using an IDEXX Filta-Max^TM foam filter. A method
modification using this filter already is approved by EPA in the
April 2001 versions of the methods.
(9) Addition of BTF EasySeed^TM irradiated oocysts and
cysts as acceptable materials for spiking routine QC samples. EPA
approved the use of EasySeed^TM based on side-by-side
comparison tests of method recoveries using EasySeed^TM
and live, untreated organisms. EPA issued a letter (dated August 1,
2002) approving EasySeed^TM for use in routine QC samples
for EPA Methods 1622 and 1623 and for demonstrating comparability of
method modifications in a single laboratory.
(10) Removal of the Whatman Nuclepore CrypTest^TM
cartridge filter. Although a method modification using this filter
was approved by EPA in the April 2001 versions of the methods, the
filter is no longer available from the manufacturer, and so is no
longer an option for sample filtration.

The changes in the June 2003 draft revisions of EPA Methods 1622
and 1623 reflect method-related clarifications, modifications, and
additions that EPA believes should be addressed for LT2ESWTR
Cryptosporidium monitoring. Alternatively, these issues could be
addressed through regulatory requirements in the final LT2ESWTR (for
required changes and additions) and through guidance (for recommended
changes and clarifications). However, EPA believes that addressing
these issues through a single source in updated versions of EPA Methods
1622 and 1623 (which could be approved in the final LT2ESWTR) may be
more straightforward and easier for systems and laboratories to follow
than addressing them in multiple sources (i.e., existing methods, the
final rule, and laboratory guidance).
2. E. coli
a. What is EPA proposing today? For enumerating source water E.
coli density under the LT2ESWTR, EPA is proposing to approve the same
methods that were proposed by EPA under Guidelines Establishing Test
Procedures for the Analysis of Pollutants; Analytical Methods for
Biological Pollutants in Ambient Water (66 FR 45811, August 30, 2001)
(USEPA 2001i). These methods are summarized in Table IV-37. Methods are
listed within the general categories of most probable number tests and
membrane filtration tests. Method identification numbers are provided
for applicable standards published by EPA and voluntary consensus
standards bodies (VCSB) including Standard Methods, American Society of
Testing Materials (ASTM), and the Association of Analytical Chemists
(AOAC).

Table IV-37.-- Proposed Methods for E. Coli Enumeration \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
VCSB methods
---------------------------------------
Technique Method\1\ EPA Standard Commercial example
methods\2\ ASTM\3\ AOAC\4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Most Probable Number (MPN)... LTB, EC-MUG...................... ............ 9221B.1/
9221F
ONPG-MUG......................... ............ 9223B ........... 991.15 Colilert[reg]\5\.
ONPG-MUG......................... ............ 9223B ........... ........... Colilert-18[reg]⁵ ⁷.
Membrane Filter (MF)......... mFC[rtarr3]NA-MUG................ ............ 9222D/
9222G
mENDO or LES-ENDO[rtarr3]NA-MUG.. ............ 9222B/
9222G
mTEC agar........................ 1103.1 9213D D5392-93
Modified mTEC agar............... 1603
MI medium........................ 1604
m-ColiBlue24 broth............... ............ ........... ........... ........... m-ColiBlue24\6\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Tests must be conducted in a format that provides organism enumeration.
\2\ Standard Methods for the Examination of Water and Wastewater. American Public Health Association. 20th, 19th, and 18th Editions. Amer. Publ. Hlth.
Assoc., Washington, DC.
\3\ Annual Book of ASTM Standards--Water and Environmental Technology. Section 11.02. ASTM. 100 Barr Harbor Drive, West Conshohocken, PA 19428.
\4\ Official Methods of Analysis of AOAC International, 16th Edition, Volume I, Chapter 17. AOAC International. 481 North Frederick Avenue, Suite 500,
Gaithersburg, Maryland 20877-2417.
\5\ Manufactured by IDEXX Laboratories, Inc., One IDEXX Drive, Westbrook, Maine 04092.
\6\ Manufactured by Hach Company, 100 Dayton Ave., Ames, IA 50010.
\7\ Acceptable version of method approved as a drinking water alternative test procedure.

EPA is proposing to allow a holding time of 24 hours for E. coli
samples. The holding time refers to the time between sample collection
and initiation of analysis. Currently, 40 CFR 141.74(a) limits the
holding time for source water coliform samples to 8 hours and requires
that samples be kept below 10[deg]C during transit. EPA believes that
new studies, described later in this section, demonstrate that E. coli
analysis results for samples held for 24 hours will be comparable to
samples held for 8 hours, provided the samples are held below 10[deg]C
and are not allowed to freeze. This proposed increase in holding time
is significant for the LT2ESWTR because typically it is not feasible
for systems to meet an 8-hour holding time when samples cannot be
analyzed on-site. Many small systems that will conduct E. coli
monitoring under the LT2ESWTR lack a certified on-site laboratory for
E. coli analyses and will be required to ship samples to a certified
laboratory. EPA believes that it is feasible for these systems to
comply with a 24 hour holding time for E. coli samples through using
overnight delivery services.
b. How was this proposal developed? As noted, EPA recently proposed
methods for ambient water E. coli analysis under Guidelines
Establishing Test Procedures for the Analysis of Pollutants; Analytical
Methods for

[[Page 47734]]

Biological Pollutants in Ambient Water (66 FR 45811, August 30, 2001)
(USEPA 2001i). These proposed methods were selected based on data
generated by EPA laboratories, submissions to the alternate test
procedures (ATP) program and voluntary consensus standards bodies,
published peer reviewed journal articles, and publicly available study
reports.
The source water analysis for E. coli that will be conducted under
the LT2ESWTR is similar to the type of ambient water analyses for which
these methods were previously proposed (66 FR 45811, August 30, 2001)
(USEPA 2001i). EPA continues to support the findings of this earlier
proposal and believes that these methods have the necessary sensitivity
and specificity to meet the data quality objectives of the LT2ESWTR.
New Information on E. coli Sample Holding Time
It is generally not feasible for systems that must ship E. coli
samples to an off-site laboratory to comply with an 8-hour holding time
requirement. During the ICRSS, 100% of the systems that shipped samples
off-site for E. coli analysis exceeded the 8 hour holding time; 12% of
these samples had holding times in excess of 30 hours. Most large
systems that will be required to monitor for E. coli under the LT2ESWTR
could conduct these analyses on-site, but many small systems will need
to ship samples off-site to a certified contract laboratory.
EPA participated in three phases of studies to assess the effect of
increased sample holding time on E. coli analysis results. These are
summarized as follows, and are described in detail in Pope et al.
(2003).
[sbull] Phase 1-EPA, the Wisconsin State Laboratory of Hygiene
(WSLH), and DynCorp conducted a study to evaluate E. coli sample
concentrations from four sites at 8, 24, 30, and 48 hours after sample
collection for samples stored at 4[deg]C, 10[deg]C, 20[deg]C, and
35[deg]C. Temperature was varied to assess the effect of different
shipping conditions. Samples were analyzed in triplicate by membrane
filtration (mFC followed by transfer to NA-MUG) and Colilert (Quanti-
Tray 2000) (Pope et al. 2003).
[sbull] Phase 2-EPA conducted a study to evaluate E. coli sample
concentrations from seven sites at 8, 24, 30, and 48 hours after sample
collection for samples stored in coolers containing wet ice or Utek ice
packs (to assess real-world storage conditions). Samples were analyzed
in triplicate by membrane filtration (mFC followed by transfer to NA-
MUG) and Colilert (Quanti-Tray 2000) (Pope et al. 2003).
[sbull] Phase 3-EPA, through cooperation with AWWA, obtained E.
coli holding time data from ten drinking water utilities that evaluated
samples from 12 source waters. Each utility used an E. coli method of
its choice (Colilert, mTEC, mEndo to NA-MUG, or mFC to NA-MUG). Samples
were stored in coolers with wet ice, Utek ice packs, or Blue ice (Pope
et al. 2003).
Phase 1 results indicated that E. coli concentrations were not
significantly different after 24 hours at most sites when samples were
stored at lower temperatures. Results from Phase 2, which evaluated
actual sample storage practices, verified the Phase 1 observations at
most sites. Similar results were observed during Phase 3, which
evaluated a wider variety of surface waters from different regions
throughout the U.S. During Phase 3, E. coli concentrations were not
significantly different after 24 hours at most sites when samples were
maintained below 10[deg]C and did not freeze during storage. At longer
holding times (e.g., 48 hours), larger differences were observed.
Based on these studies, EPA has concluded that E. coli samples can
be held for up to 24 hours prior to analysis without compromising the
data quality objectives of LT2ESWTR E. coli monitoring. Further, EPA
believes that it is feasible for systems that must ship E. coli samples
to an off-site laboratory for analysis to meet a 24 hour holding time.
EPA is developing guidance for systems on packing and shipping E. coli
samples so that samples are maintained below 10[deg]C and not allowed
to freeze (USEPA 2003g). This guidance is available in draft in the
docket for today's proposal (http://www.epa.gov/edocket/).
c. Request for comment. EPA requests comment on whether the E. coli
methods proposed for approval under the LT2ESWTR are appropriate, and
whether there are additional methods not proposed that should be
considered. Comments concerning method approval should be accompanied
by supporting data where possible.
EPA also requests comment on the proposal to extend the holding
time for E. coli source water sample analyses to 24 hours, including
any data or other information that would support, modify, or repudiate
such an extension. Should EPA limit the extended holding time to only
those E. coli analytical methods that were evaluated in the holding
time studies noted in this section? The results in Pope et al. (2003)
indicate that most E. coli samples analyzed using ONPG-MUG (see methods
in Table IV-37) incurred no significant degradation after a 30 to 48
hour holding time. As a result, should EPA increase the source water E.
coli holding time to 30 or 48 hours for samples evaluated by ONPG-MUG,
and retain a 24-hour holding time for samples analyzed by other
methods? EPA also requests comment on the cost and availability of
overnight delivery services for E. coli samples, especially in rural
areas.
3. Turbidity
a. What is EPA proposing today? For turbidity analyses that will
be conducted under the LT2ESWTR, EPA is proposing to require systems to
use the analytical methods that have been previously approved by EPA
for analysis of turbidity in drinking water, as listed in 40 CFR Part
141.74. These are Method 2130B as published in Standard Methods for the
Examination of Water and Wastewater (APHA 1992), EPA Method 180.1
(USEPA 1993), and Great Lakes Instruments Method 2 (Great Lakes
Instruments, 1992), and Hach FilterTrak Method 10133.
EPA method 180.1 and Standard Method 2130B are both nephelometric
methods and are based upon a comparison of the intensity of light
scattered by the sample under defined conditions with the intensity of
light scattered by a standard reference suspension. Great Lakes
Instruments Method 2 is a modulated four beam infrared method using a
ratiometric algorithm to calculate the turbidity value from the four
readings that are produced. Hach Filter Trak (Method 10133) is a laser-
based nephelometric method used to determine the turbidity of finished
drinking waters.
Turbidimeters
Systems are required to use turbidimeters described in EPA-approved
methods for measuring turbidity. For regulatory reporting purposes,
either an on-line or a bench top turbidimeter can be used. If a system
chooses to use on-line units for monitoring, the system must validate
the continuous measurements for accuracy on a regular basis using a
protocol approved by the State.
b. How was this proposal developed? EPA believes the currently
approved methods for analysis of turbidity in drinking water are
appropriate for turbidity analyses that will be conducted under the
LT2ESWTR.
c. Request for comment. EPA requests comment on whether the
turbidity methods proposed today for the LT2ESWTR should be approved,
and whether there are additional methods not proposed that should be
approved.

[[Page 47735]]

L. Laboratory Approval

Given the potentially significant implications in terms of both
cost and public health protection of microbial monitoring under the
LT2ESWTR, laboratory analyses for Cryptosporidium, E. coli, and
turbidity must be accurate and reliable within the limits of approved
methods. Therefore, EPA proposes to require public water systems to use
laboratories that have been approved to conduct analyses for these
parameters by EPA or the State. The following criteria are proposed for
laboratory approval under the LT2ESWTR:
[sbull] For Cryptosporidium analyses under the LT2ESWTR, EPA
proposes to approve laboratories that have passed a quality assurance
evaluation under EPA's Laboratory Quality Assurance Evaluation Program
(Lab QA Program) for Analysis of Cryptosporidium in Water (described in
67 FR 9731, March 4, 2002) (USEPA 2002c). If States adopt an equivalent
approval process under State laboratory certification programs, then
systems can use laboratories approved by the State.
[sbull] For E. coli analyses, EPA proposes to approve laboratories
that have been certified by EPA, the National Environmental Laboratory
Accreditation Conference, or the State for total coliform or fecal
coliform analysis in source water under 40 CFR 141.74. The laboratory
must use the same analytical technique for E. coli that the laboratory
uses for total coliform or fecal coliform analysis under 40 CFR 141.74.
[sbull] Turbidity analyses must be conducted by a person approved
by the State for analysis of turbidity in drinking water under 40 CFR
141.74.
These criteria are further described in the following paragraphs.
1. Cryptosporidium Laboratory Approval
Because States do not currently approve laboratories for
Cryptosporidium analyses and LT2ESWTR monitoring will begin 6 months
after rule promulgation, EPA will initially assume responsibility for
Cryptosporidium laboratory approval. EPA expects, however, that States
will include Cryptosporidium analysis in their State laboratory
certification programs in the future. EPA has established the Lab QA
Program for Cryptosporidium analysis to identify laboratories that can
meet LT2ESWTR data quality objectives. This is a voluntary program open
to laboratories involved in analyzing Cryptosporidium in water. Under
this program, EPA assesses the ability of laboratories to reliably
measure Cryptosporidium occurrence with EPA Methods 1622 and 1623,
using both performance testing samples and an on-site evaluation.
EPA initiated the Lab QA Program for Cryptosporidium analysis prior
to promulgation of the LT2ESWTR to ensure that adequate sample analysis
capacity will be available at qualified laboratories to support the
required monitoring. The Agency is monitoring sample analysis capacity
at approved laboratories through the Lab QA Program, and does not plan
to implement LT2ESWTR monitoring until the Agency determines that there
is adequate laboratory capacity. In addition, utilities that choose to
conduct Cryptosporidium monitoring prior to LT2ESWTR promulgation with
the intent of grandfathering the data may elect to use laboratories
that have passed the EPA quality assurance evaluation.
Laboratories seeking to participate in the EPA Lab QA Program for
Cryptosporidium analysis must submit an interest application to EPA,
successfully analyze a set of initial performance testing samples, and
undergo an on-site evaluation. The on-site evaluation includes two
separate but concurrent assessments: (1) Assessment of the laboratory's
sample processing and analysis procedures, including microscopic
examination, and (2) evaluation of the laboratory's personnel
qualifications, quality assurance/quality control program, equipment,
and recordkeeping procedures.
Laboratories that pass the quality assurance evaluation will be
eligible for approval for Cryptosporidium analysis under the LT2ESWTR.
The Lab QA Program is described in detail in a Federal Register Notice
(67 FR 9731, March 4, 2002) (USEPA 2002c) and additional information
can be found online at: www.epa.gov/safewater/lt2/cla_int.html.
Laboratories in the Lab QA Program will receive a set of three
ongoing proficiency testing (OPT) samples approximately every four
months. EPA will evaluate the precision and recovery data for OPT
samples to determine if the laboratory continues to meet the
performance criteria of the Laboratory QA Program.
2. E. coli Laboratory Approval
Pubic water systems are required to have samples analyzed for E.
coli by laboratories certified under the State drinking water
certification program to perform total coliform and fecal coliform
analyses under 40 CFR 141.74. EPA is proposing that the general
analytical techniques the laboratory is certified to use under the
drinking water certification program (e.g., membrane filtration,
multiple-well, multiple-tube) will be the methods the laboratory can
use to conduct E. coli source water analyses under the LT2ESWTR.
3. Turbidity Analyst Approval
Measurements of turbidity must be conducted by a party approved by
the State. This is consistent with current requirements for turbidity
measurements in drinking water (40 CFR 141.74).
4. Request for Comment
EPA requests comment on the laboratory approval requirements
proposed today, including the following specific issues:
Analyst Experience Criteria
The Lab QA Program, which EPA will use to approve laboratories for
Cryptosporidium analyses under the LT2ESWTR, includes criteria for
analyst experience. Principal analyst/supervisors (minimum of one per
laboratory) should have a minimum of one year of continuous bench
experience with Cryptosporidium and immunofluorescent assay (IFA)
microscopy, a minimum of six months experience using EPA Method 1622
and/or 1623, and a minimum of 100 samples analyzed using EPA Method
1622 and/or 1623 (minimum 50 samples if the person was an analyst
approved to conduct analysis for the Information Collection Rule
Protozoan Method) for the specific analytical procedure they will be
using.
Under the Lab QA Program, other analysts (no minimum number of
analysts per laboratory) should have a minimum of six months of
continuous bench experience with Cryptosporidium and IFA microscopy, a
minimum of three months experience using EPA Method 1622 and/or 1623,
and a minimum of 50 samples analyzed using EPA Method 1622 and/or 1623
(minimum 25 samples if the person was an analyst approved to conduct
analysis for the Information Collection Rule Protozoan Method) for the
specific analytical procedures they will be using.
The Lab QA Program criteria for principal analyst/supervisor
experience are more rigorous than those in Methods 1622 and 1623, which
are as follows: the analyst must have at least 2 years of college
lecture and laboratory course work in microbiology or a closely related
field. The analyst also must have at least 6 months of continuous bench
experience with environmental protozoa detection techniques and IFA

[[Page 47736]]

microscopy, and must have successfully analyzed at least 50 water and/
or wastewater samples for Cryptosporidium. Six months of additional
experience in the above areas may be substituted for two years of
college.
In seeking approval for an Information Collection Request, EPA
requested comment on the Lab QA Program (67 FR 9731, March 4, 2002)
(USEPA 2002c). A number of commenters stated that the analyst
qualification criteria are restrictive and could make it difficult for
laboratories to maintain adequate analyst staffing (and, hence, sample
analysis capacity) in the event of staff turnover or competing
priorities. Some commenters suggested that laboratories and analysts
should be evaluated based on proficiency testing, and that analyst
experience standards should be reduced or eliminated. (Comments are
available in Office of Water docket, number W-01-17).
Another aspect of the analyst experience criteria is that systems
may generate Cryptosporidium data for grandfathering under the LT2ESWTR
using laboratories that meet the analyst experience requirement of
Methods 1622 or 1623 but not the more rigorous principal analyst/
supervisor experience requirement of the Lab QA Program.
EPA requests comment on whether the criteria for analyst experience
in the Lab QA Program are necessary, whether systems are experiencing
difficulty in finding laboratories that have passed the Lab QA Program
to conduct Cryptosporidium analysis, and whether any of the Lab QA
Program criteria should be revised to improve the LT2ESWTR lab approval
process.
State Programs To Approve Laboratories for Cryptosporidium Analysis
Under today's proposal, systems must have Cryptosporidium samples
analyzed by a laboratory approved under EPA's Lab QA Program, or an
equivalent State laboratory approval program. Because States do not
currently approve laboratories for Cryptosporidium analyses, EPA will
initially assume responsibility for Cryptosporidium laboratory
approval. EPA expects, however, that States will adopt equivalent
approval programs for Cryptosporidium analysis under State laboratory
certification programs. EPA requests comment on how to establish that a
State approval program for Cryptosporidium analysis is equivalent to
the Lab QA Program.
Specifically, should EPA evaluate State Approval programs to
determine if they are equivalent to the Lab QA Program? EPA also
requests comment on the elements that would constitute an equivalent
State approval program for Cryptosporidium analyses, including the
following: (1) Successful analysis of initial and ongoing blind
proficiency testing samples prepared using flow cytometry, including a
matrix and meeting EPA's pass/fail criteria (described in USEPA 2002c);
(2) an on-site evaluation of the laboratory's sample processing and
analysis procedures, including microscopic examination skills, by
auditors who meet the qualifications of a principal analyst as set
forth in the Lab QA Program (described in USEPA 2002c); (3) an on-site
evaluation of the laboratory's personnel qualifications, quality
assurance/quality control program, equipment, and recordkeeping
procedures; (4) a data audit of the laboratories' QC data and
monitoring data; and (5) use of the audit checklist used in the Lab QA
Program or equivalent.

M. Requirements for Sanitary Surveys Conducted by EPA

1. Overview
In today's proposal, EPA is requesting comment on establishing
requirements for public water systems with significant deficiencies as
identified in a sanitary survey conducted by EPA under SDWA section
1445. These requirements would apply to surface water systems for which
EPA is responsible for directly implementing national primary drinking
water regulations (i.e., systems not regulated by States with primacy).
As described in this section, these requirements would ensure that
systems in non-primacy States, currently Wyoming, and systems not
regulated by States, such as Tribal systems, are subject to standards
for sanitary surveys similar to those that apply to systems regulated
by States with primacy.
2. Background
As established by the IESWTR in 40 CFR 142.16(b)(3), primacy States
must conduct sanitary surveys for all surface water systems no less
frequently than every three years for community water systems and no
less frequently than every five years for noncommunity water systems.
The sanitary survey is an onsite review and must address the following
eight components: (1) Source, (2) treatment, (3) distribution system,
(4) finished water storage, (5) pumps, pump facilities, and controls,
(6) monitoring, reporting, and data verification, (7) system management
and operation, and (8) operator compliance with State requirements.
Under the IESWTR, primacy States are required to have the
appropriate rules or other authority to assure that systems respond in
writing to significant deficiencies outlined in sanitary survey reports
no later than 45 days after receipt of the report, indicating how and
on what schedule the system will address significant deficiencies noted
in the survey (40 CFR 142.16(b)(1)(ii)). Further, primacy States must
have the authority to assure that systems take necessary steps to
address significant deficiencies identified in sanitary survey reports
if such deficiencies are within the control of the system and its
governing body (40 CFR 142.16(b)(1)(iii)). The IESWTR did not define a
significant deficiency, but required that primacy States describe in
their primacy applications how they will decide whether a deficiency
identified during a sanitary survey is significant for the purposes of
the requirements stated in this paragraph (40 CFR 142.16(b)(3)(v)).
EPA conducts sanitary surveys under SDWA section 1445 for public
water systems not regulated by primacy States (e.g., Tribal systems,
Wyoming). However, EPA does not have the authority required of primacy
States under 40 CFR 142 to ensure that systems address significant
deficiencies identified during sanitary surveys. Consequently, the
sanitary survey requirements established by the IESWTR create an
unequal standard. Systems regulated by primacy States are subject to
the States' authority to require correction of significant deficiencies
noted in sanitary survey reports, while systems for which EPA has
direct implementation authority do not have to meet an equivalent
requirement.
3. Request for Comment
In order to ensure that systems for which EPA has direct
implementation authority address significant deficiencies identified
during sanitary surveys, EPA requests comment on establishing either or
both of the following requirements under 40 CFR 141 as part of the
NPDWR established in the final LT2ESWTR:

(1) For sanitary surveys conducted by EPA under SDWA section
1445, systems would be required to respond in writing to significant
deficiencies outlined in sanitary survey reports no later than 45
days after receipt of the report, indicating how and on what
schedule the system will address significant deficiencies noted in
the survey.
(2) Systems would be required to correct significant
deficiencies identified in sanitary survey reports if such
deficiencies are within the control of the system and its governing
body.

[[Page 47737]]

For the purposes of these requirements, a sanitary survey, as
conducted by EPA, is an onsite review of the water source (identifying
sources of contamination by using results of source water assessments
where available), facilities, equipment, operation, maintenance, and
monitoring compliance of a public water system to evaluate the adequacy
of the system, its sources and operations, and the distribution of safe
drinking water. A significant deficiency includes a defect in design,
operation, or maintenance, or a failure or malfunction of the sources,
treatment, storage, or distribution system that EPA determines to be
causing, or has the potential for causing the introduction of
contamination into the water delivered to consumers.

V. State Implementation

This section describes the regulations and other procedures and
policies States will be required to adopt to implement the LT2ESWTR, if
finalized as proposed today. States must continue to meet all other
conditions of primacy in 40 CFR Part 142.
The Safe Drinking Water Act (Act) establishes requirements that a
State or eligible Indian tribe must meet to assume and maintain primary
enforcement responsibility (primacy) for its public water systems.
These requirements include: (1) Adopting drinking water regulations
that are no less stringent than Federal drinking water regulations, (2)
adopting and implementing adequate procedures for enforcement, (3)
keeping records and making reports available on activities that EPA
requires by regulation, (4) issuing variances and exemptions (if
allowed by the State), under conditions no less stringent than allowed
under the Act, and (5) adopting and being capable of implementing an
adequate plan for the provisions of safe drinking water under emergency
situations.
40 CFR part 142 sets out the specific program implementation
requirements for States to obtain primacy for the public water supply
supervision program as authorized under section 1413 of the Act. In
addition to adopting basic primacy requirements specified in 40 CFR
Part 142, States may be required to adopt special primacy provisions
pertaining to specific regulations where implementation of the rule
involves activities beyond general primacy provisions. States must
include these regulation specific provisions in an application for
approval of their program revision. Primacy requirements for today's
proposal are discussed below.
To implement the proposed LT2ESWTR, States will be required to
adopt revisions to:
Sec. 141.2--Definitions
Sec. 141.71--Criteria for avoiding filtration
Sec. 141.153--Content of the reports
Sec. 141.170--Enhanced filtration and disinfection
Subpart Q--Public Notification
New Subpart W--Additional treatment technique requirements for
Cryptosporidium
Sec. 142.14--Records kept by States
Sec. 142.15--Reports by States
Sec. 142.16--Special primacy requirements

A. Special State Primacy Requirements

To ensure that a State program includes all the elements necessary
for an effective and enforceable program under today's rule, a State
primacy application must include a description of how the State will
perform the following:
(1) Approve watershed control programs for the 0.5 log watershed
control program credit in the microbial toolbox (see section IV.C.2);
(2) Assess significant changes in the watershed and source water as
part of the sanitary survey process and determine appropriate follow-up
action (see section IV.A);
(3) Determine that a system with an uncovered finished water
storage facility has a risk mitigation plan that is adequate for
purposes of waiving the requirement to cover the storage facility or
treat the effluent (see section IV.E);
(4) Approve protocols for removal credits under the Demonstration
of Performance toolbox option (see section IV.C.17) and for site
specific chlorine dioxide and ozone CT tables (see section IV.C.14);
and
(5) Approve laboratories to analyze for Cryptosporidium.
Note that a State program can be more, but not less, stringent than
Federal regulations. As such, some of the elements listed here may not
be applicable to a specific State program. For example, if a State
chooses to require all finished water storage facilities to be covered
or provide treatment and not to allow a risk mitigation plan to
substitute for this requirement, then the description for item (3)
would be inapplicable.

B. State Recordkeeping Requirements

The current regulations in Sec. 142.14 require States with primacy
to keep various records, including the following: Analytical results to
determine compliance with MCLs, MRDLs, and treatment technique
requirements; system inventories; State approvals; enforcement actions;
and the issuance of variances and exemptions. The proposed LT2ESWTR
will require States to keep additional records of the following,
including all supporting information and an explanation of the
technical basis for each decision:
[sbull] Results of source water E. coli and Cryptosporidium
monitoring;
[sbull] Cryptosporidium bin classification for each filtered
system, including any changes to initial bin classification based on
review of the watershed during sanitary surveys or the second round of
monitoring;
[sbull] Determination of whether each unfiltered system has a mean
source water Cryptosporidium level above 0.01 oocysts/L;
[sbull] The treatment processes or control measures that each
system employs to meet Cryptosporidium treatment requirements under the
LT2ESWTR; this includes documentation to demonstrate compliance with
required design and implementation criteria for receiving credit for
microbial toolbox options, as specified in section IV.C;
[sbull] A list of systems required to cover or treat the effluent
of an uncovered finished water storage facilities; and
[sbull] A list of systems for which the State has waived the
requirement to cover or treat the effluent of an uncovered finished
water storage facility, along with supporting documentation of the risk
mitigation plan.

C. State Reporting Requirements

EPA currently requires in Sec. 142.15 that States report to EPA
information such as violations, variance and exemption status, and
enforcement actions. The LT2ESWTR, as proposed, will add additional
reporting requirements in the following area:
[sbull] The Cryptosporidium bin classification for each filtered
system, including any changes to initial bin classification based on
review of the watershed during sanitary surveys or the second round of
monitoring;
[sbull] The determination of whether each unfiltered system has a
mean source water Cryptosporidium level above 0.01 oocysts/L, including
any changes to this determination based on the second round of
monitoring.

D. Interim Primacy

On April 28, 1998, EPA amended its State primacy regulations at 40
CFR 142.12 to incorporate the new process identified in the 1996 SDWA
Amendments for granting primary enforcement authority to States while
their applications to modify their primacy programs are under review
(63 FR 23362, April 28, 1998) (USEPA 1998f). The new process grants
interim

[[Page 47738]]

primary enforcement authority for a new or revised regulation during
the period in which EPA is making a determination with regard to
primacy for that new or revised regulation. This interim enforcement
authority begins on the date of the primacy application submission or
the effective date of the new or revised State regulation, whichever is
later, and ends when EPA makes a final determination. However, this
interim primacy authority is only available to a State that has primacy
(including interim primacy) for every existing NPDWR in effect when the
new regulation is promulgated.
As a result, States that have primacy for every existing NPDWR
already in effect may obtain interim primacy for this rule, beginning
on the date that the State submits the application for this rule to
USEPA, or the effective date of its revised regulations, whichever is
later. In addition, a State that wishes to obtain interim primacy for
future NPDWRs must obtain primacy for this rule. As described in
Section IV.A, EPA expects to oversee the initial source water
monitoring that will be conducted under the LT2ESWTR by systems serving
at least 10,000 people, beginning 6 months following rule promulgation.

VI. Economic Analysis

This section summarizes the economic analysis (EA) for the LT2ESWTR
proposal. The EA is an assessment of the benefits, both health and non-
health related, and costs to the regulated community of the proposed
regulation, along with those of regulatory alternatives that the Agency
considered. EPA developed this EA to meet the requirement of SDWA
section 1412(b)(3)(C) for a Health Risk Reduction and Cost Analysis
(HRRCA), as well as the requirements of Executive Order 12866,
Regulatory Planning and Review, under which EPA must estimate the costs
and benefits of the LT2ESWTR. The full EA is presented in Economic
Analysis for the Long Term 2 Enhanced Surface Water Treatment Rule
(USEPA 2003a), which is available in the docket for today's proposal
(www.epa.gov.edocket/).
Today's proposed LT2ESWTR is the second in a staged set of rules
that address public health risks from microbial contamination of
surface and GWUDI drinking water supplies and, more specifically,
prevent Cryptosporidium from reaching consumers. As described in
section I, the Agency promulgated the IESWTR and LT1ESWTR to provide a
baseline of protection against Cryptosporidium in large and small
drinking water systems, respectively. Today's proposed rule would
achieve further reductions in Cryptosporidium exposure for systems with
the highest vulnerability. This economic analysis considers only the
incremental reduction in exposure from the two previously promulgated
rules (IESWTR and LT1ESWTR) to the alternatives evaluated for the
LT2ESWTR.
Both benefits and costs are determined as annualized present
values. The process allows comparison of cost and benefit streams that
are variable over a given time period. The time frame used for both
benefit and cost comparisons is 25 years; approximately five years
account for rule implementation and 20 years for the average useful
life of the equipment used to comply with treatment technique
requirements. The Agency uses social discount rates of both three
percent and seven percent to calculate present values from the stream
of benefits and costs and also to annualize the present value estimates
(see EPA's Guidelines for Preparing Economic Analyses (USEPA 2000c) for
a discussion of social discount rates). The LT2ESWTR EA (USEPA 2003a)
also shows the undiscounted stream of both benefits and costs over the
25 year time frame.

A. What Regulatory Alternatives Did the Agency Consider?

Regulatory alternatives considered by Agency for the LT2ESWTR were
developed through the deliberations of the Stage 2 M-DBP Federal
Advisory Committee (described in section II). The Committee considered
several general approaches for reducing the risk from Cryptosporidium
in drinking water. As discussed in section IV.A.2, these approaches
included both additional treatment requirements for all systems and
risk-targeted treatment requirements for systems with the highest
vulnerability to Cryptosporidium following implementation of the IESWTR
and LT1ESWTR. In addition, the Committee considered related factors
such as surrogates for Cryptosporidium monitoring and alternative
monitoring strategies to minimize costs to small drinking water
systems.
After considering these general approaches, the Committee focused
on four specific regulatory alternatives for filtered systems (see
Table VI-1). With the exception of Alternative 1, which requires all
systems to achieve an additional 2 log (99%) reduction in
Cryptosporidium levels, these alternatives incorporate a microbial
framework approach. In this approach, systems are classified in
different risk bins based on the results of source water monitoring.
Additional treatment requirements are directly linked to the risk bin
classification. Accordingly, these rule alternatives are differentiated
by two criteria: (1) The Cryptosporidium concentrations that define the
bin boundaries and (2) the degree of treatment required for each bin.
In assessing regulatory alternatives, EPA and the Advisory
Committee were concerned with the following questions: (1) Do the
treatment requirements adequately control Cryptosporidium
concentrations in finished water? (2) How many systems will be required
to add treatment? (3) What is the likelihood that systems with high
source water Cryptosporidium concentrations will not be required to
provide additional treatment (i.e., be misclassified in a low risk
bin)? and (4) What is the likelihood that systems with low source water
Cryptosporidium concentrations will be required to provide unnecessary
additional treatment (i.e., misclassified in a high risk bin)?
The Committee reached consensus regarding additional treatment
requirements for unfiltered systems and uncovered finished water
storage facilities without formally identifying regulatory
alternatives. Table VI-1 summarizes the four alternatives that were
considered for filtered systems.

[[Page 47739]]

Table VI-1.--Summary of Regulatory Alternatives for Filtered Systems
------------------------------------------------------------------------
Average source water Cryptosporidium Additional treatment
monitoring result (oocysts/L) requirements \1\
------------------------------------------------------------------------
Alternative A1
2.0 log inactivation required for all systems
Alternative A2
------------------------------------------------------------------------
< 0.03........................................ No action.
= 0.03 and < 0.1................... 0.5 log.
= 0.1 and < 1.0.................... 1.5 log.
= 1.0.............................. 2.5 log.
-----------------------------------------------
Alternative A3--Preferred Alternative
------------------------------------------------------------------------
< 0.075....................................... No action.
= 0.075 and < 1.0.................. 1 log.
= 1.0 and < 3.0.................... 2 log.
= 3.0.............................. 2.5 log.
-----------------------------------------------
Alternative A4
------------------------------------------------------------------------
< 0.1......................................... No action.
= 0.1 and < 1.0.................... 0.5-log.
=1.0............................... 1.0 log.
------------------------------------------------------------------------
\1\ Note: ``Additional treatment requirements'' are in addition to
levels already required under existing rules (e.g., the IESWTR and
LT1ESWTR).

B. What Analyses Support Selecting the Proposed Rule Option?

EPA has quantified benefits and costs of each of the regulatory
alternatives in Table VI-1, as well as for the proposed requirements
for unfiltered systems. Quantified benefits stem from estimated
reductions in the incidence of cryptosporidiosis resulting from the
regulation. To make these estimates, the Agency developed a two-
dimensional Monte Carlo model that accounts for uncertainty and
variability in key parameters like Cryptosporidium occurrence,
infectivity, and treatment efficiency. Analyses involved estimating the
baseline (pre-LT2ESWTR) risk from Cryptosporidium in drinking water,
and then projecting the reductions in exposure and risk resulting from
the additional treatment requirements of the LT2ESWTR. Costs result
largely from the installation of additional treatment, with lesser
costs due to monitoring and other implementation activities. Results of
these analyses are summarized in the following subsections, and details
are shown in the LT2ESWTR EA (USEPA 2003a).
Cryptosporidium occurrence significantly influences the estimated
benefits and costs of regulatory alternatives. As discussed in section
III.C, EPA analyzed data collected under the Information Collection
Rule, the Information Collection Rule Supplemental Surveys of medium
systems (ICRSSM), and the Information Collection Rule Supplemental
Surveys of large systems (ICRSSL) to estimate the national occurrence
distribution of Cryptosporidium in surface water. EPA evaluated these
distributions independently when assessing benefits and costs for
different regulatory alternatives. In most cases, results from the
ICRSSM data set are within the range of results of the Information
Collection Rule and ICRSSL data sets.
EPA selected a Preferred Regulatory Alternative for the LT2ESWTR,
consistent with the recommendations of the Advisory Committee. As
described next, this selection was based on the estimated impacts and
feasibility of the alternatives shown in Table VI-1.
Alternative A1 (across-the-board 2-log inactivation) was not
selected because it was the highest cost option and imposed costs but
provided few benefits to systems with high quality source water (i.e.,
relatively low Cryptosporidium risk). In addition, there were concerns
about the feasibility of requiring almost every surface water treatment
plant to install additional treatment processes (e.g., UV or ozone) for
Cryptosporidium.
Alternatives A2-A4 were evaluated based on several factors,
including predictions of costs and benefits, performance of analytical
methods for classifying systems in the risk bins, and other specific
impacts (e.g., impacts on small systems or sensitive subpopulations).
Alternative A3 was recommended by the Advisory Committee because it
provides significant health benefits in terms of avoided illnesses and
deaths for an acceptable cost. In addition, the Agency believes this
alternative is feasible with available analytical methods and treatment
technologies.
Incremental costs and benefits of regulatory alternatives for the
LT2ESWTR are shown in section VI.F, and the LT2ESWTR EA contains more
detailed information about the benefits and costs of each regulatory
option (USEPA 2003a).

C. What Are the Benefits of the Proposed LT2ESWTR?

As discussed previously, the LT2ESWTR is expected to substantially
reduce drinking water related exposure to Cryptosporidium, thereby
reducing both illness and death associated with cryptosporidiosis. As
described in section II, cryptosporidiosis is an infection caused by
Cryptosporidium and is an acute, typically self-limiting, illness with
symptoms that include diarrhea, abdominal cramping, nausea, vomiting,
and fever (Juranek, 1995). Cryptosporidiosis patients in sensitive
subpopulations, such as infants, the elderly, and AIDS patients, are at
risk for severe illness, including risk of death. While EPA has
quantified and monetized the health benefits for reductions in endemic
cryptosporidiosis that would result from the LT2ESWTR, the Agency was
unable to quantify or monetize other health and non-health related
benefits associated with this rule. These unquantified benefits are
characterized next, followed by a summary of the quantified benefits.

[[Page 47740]]

1. Non-Quantifiable Health and Non-health Related Benefits
Although there are substantial monetized benefits that result from
this rule due to reduced rates of endemic cryptosporidiosis, other
potentially significant benefits of this rule remain unquantified and
non-monetized. The unquantified benefits that result from this rule are
summarized in Table VI-2 and are described in greater detail in the
LT2ESWTR EA (USEPA 2003a).

Table VI-2.--Summary of Nonquantified Benefits
------------------------------------------------------------------------
Potential effect
Benefit type on benefits Comments
------------------------------------------------------------------------
Reducing outbreak risks and Increase......... Some outbreaks are
response costs. caused by human or
equipment failures
that may occur even
with the proposed
new requirements;
however, by adding
barriers of
protection for some
systems, the rule
will reduce the
possibility of such
failures leading to
outbreaks.
Reducing averting behavior Increase / No Averting behavior is
(e.g., boiling tap water or Change. associated with both
purchasing bottled water). out-of-pocket costs
(e.g., purchase of
bottled water) and
opportunity costs
(e.g., time
requiring to boil
water) to the
consumer. Reductions
in averting behavior
are expected to have
a positive impact on
benefits from the
rule.
Improving aesthetic water Increase......... Some technologies
quality. installed for this
rule (e.g., ozone)
are likely to reduce
taste quality and
odor problems.
Reducing risk from co- Increase......... Although focused on
occurring and emerging removal of
pathogens. Cryptosporidium from
drinking water,
systems that change
treatment processes
will also increase
removal of pathogens
that the rule does
not specifically
regulate. Additional
benefits will
accrue.
Increased source water Increase......... The greater
monitoring. understanding of
source water quality
that results from
monitoring may
enhance the ability
of plants to
optimize treatment
operations in ways
other than those
addressed in this
rule.
Reduced contamination due to Increase......... Although insufficient
covering on treating finished data were available
water storage facilities. to quantify
benefits, the
reduction of
contaminants
introduced through
uncovered finished
water storage
facilities would
produce positive
public health
benefits.
------------------------------------------------------------------------
Source: Chapter 5 of the LT2ESWTR Economic Analysis (USEPA 2003a).

2. Quantifiable Health Benefits
EPA quantified benefits for the LT2ESWTR based on reductions in the
risk of endemic cryptosporidiosis. Several categories of monetized
benefits were considered in this analysis.
First, EPA estimated the number of cases expected to result in
premature mortality (primarily for members of sensitive subpopulations
such as AIDS patients). In order to estimate the benefits from deaths
avoided as a result of the rule, EPA multiplied the estimates for
number of illnesses avoided by a projected mortality rate. This
mortality rate was developed using mortality data from the Milwaukee
cryptosporidiosis outbreak of 1993 (described in section II), with
adjustments to account for the subsequent decrease in the mortality
rate among people with AIDS and for the difference between the 1993
Milwaukee AIDS rate and the current national rate. EPA estimated a
mortality rate of 16.6 deaths per 100,000 illnesses for those served by
unfiltered systems and a mortality rate of 10.6 deaths per 100,000
illnesses for those served by filtered systems. These different rates
are associated with the incidence of AIDS in populations served by
unfiltered and filtered systems. A complete discussion on how EPA
derived these rates can be found in subchapter 5.2 of the LT2ESWTR EA
(USEPA 2003a).
Reductions in mortalities were monetized using EPA's standard
methodology for monetizing mortality risk reduction. This methodology
is based on a distribution of value of statistical life (VSL) estimates
from 26 labor market and stated preference studies, with a mean VSL of
$6.3M in 2000, and a 5th to 95th percentile range of $1.0 to $14.5. A
more detailed discussion of these studies and the VSL estimate can be
found in EPA's Guidelines for Preparing Economic Analyses (USEPA
2000c). A real income growth factor was applied to these estimates of
approximately 2.3% per year for the 20 year time span following
implementation. Income elasticity for VSL was estimated as a triangular
distribution that ranged from 0.08 to 1.00, with a mode of 0.40. VSL
values for the 20 year span are shown in the LT2 EA in Exhibit C.13
(USEPA 2003a).
The substantial majority of cases are not expected to be fatal and
the Agency separately estimated the value of non-fatal illnesses
avoided that would result from the LT2ESWTR. For these, EPA first
divided projected cases into three categories, mild, moderate, and
severe, and then calculated a monetized value per case avoided for each
severity level. These were then combined into a weighted average value
per case based on the relative frequency of each severity level.
According to a study conducted by Corso et al. (2003), the majority of
illness falls into the mild category (88 percent). Approximately 11
percent of illness falls into the moderate category, which is defined
as those who seek medical treatment but are not hospitalized. The final
one percent have severe symptoms that result in hospitalization. EPA
estimated different medical expenses and time losses for each category.
Benefits for non-fatal cases were calculated using a cost-of-
illness (COI) approach. Traditional COI valuations focus on medical
costs and lost work time, and leave out significant categories of
benefits, specifically the reduced utility from being sick (i.e., lost
personal or non-work time, including activities such as child care,
homemaking, community service, time spent with family, and recreation),
although some COI studies also include an estimate for unpaid labor
(household production) valued at an estimated wage

[[Page 47741]]

rate designed to reflect the market value of such labor (e.g., median
wage for household domestic labor). This reduced utility is variously
referred to as lost leisure or a component of pain and suffering.
Ideally, a comprehensive willingness to pay (WTP) estimate would be
used that includes all categories of loss in a single number. However,
a review of the literature indicated that the available studies were
not suitable for valuing cryptosporidiosis; hence, estimates from this
literature are inappropriate for use in this analysis. Instead, EPA
presents two COI estimates: a traditional approach that only includes
valuation for medical costs and lost work time (including some portion
of unpaid household production); and an enhanced approach that also
factors in valuations for lost unpaid work time for employed people,
reduced utility (or sense of well-being) associated with decreased
enjoyment of time spent in non-work activities, and lost productivity
at work on days when workers are ill but go to work anyway.
Table VI-3 shows the various categories of loss and how they were
valued for each estimate for a ``typical'' case (weighted average of
severity level--see LT2ESWTR EA--Chapter 5 for more details (USEPA
2003a).

Table VI-3.--Traditional and Enhanced COI for Cryptosporidiosis
------------------------------------------------------------------------
Traditional
Loss category COI Enhanced COI
------------------------------------------------------------------------
Direct Medical Costs.................... $93.82 $93.82
Lost Paid Work Days..................... 109.88 109.88
Lost Unpaid Work Days \1\............... 20.22 40.44
Lost Caregiver Days \2\................. 20.70 54.31
Lost Leisure Time \3\................... \5\ 333.96
Lost Productivity at Work............... \5\ 112.49
Total \4\........................... 244.62 744.89
------------------------------------------------------------------------
\1\ Assigned to 38.2% of the population not engaged in market work;
assumes 40 hr, unpaid work week, valued at $5.46/hr in traditional COI
and $10.92/hr in enhanced COI. Does not include lost unpaid work for
employed people and may not include all unpaid work for people outside
the paid labor force.
\2\ Values lost work or leisure time for people caring for the ill.
Traditional approach does not include lost leisure time.
\3\ Includes child care and homemaking (to the extent not covered in
lost unpaid work days above), time with family, and recreation for
people within and outside the paid labor force.
\4\ Detail may not calculate to totals due to independent rounding;
Source: Appendix L in LT2ESWTR EA (USEPA 2003a).
\5\ Not included.

The various loss categories were calculated as follows: Medical
costs are a weighted average across the three illness severity levels
of actual costs for doctor and emergency room visits, medication, and
hospital stays. Lost paid work represents missed work time of paid
employees, valued at the median pre-tax wage, plus benefits of $18.47
hour. The average number of lost work hours per case is 5.95 (this
assumes that 62 percent of the population is in the paid labor force
and the loss is averaged over seven days). Medical costs and lost work
days reflect market transactions. Medical costs are always included in
COI estimates and lost work days are usually included in COI estimates.
In the traditional COI estimate, an equivalent amount of lost
unpaid work time was assigned to the 38% of the population that are not
in the paid labor force. This includes homemakers, students, children,
retires, and unemployed persons. EPA did not attempt to calculate what
percent of cases falls in each of these five groups, or how many hours
per week each group works, but rather assumed an across-the-board 40
hour unpaid work week. This time is valued at $5.46 per hour, which is
one half the median post-tax wage, (since work performed by these
groups is not taxed). This is approximately the median wage for paid
household domestic labor.
In the enhanced COI estimate, all time other than paid work and
sleep (8 hours per day) is valued at the median after tax wage, or
$10.92 per hour. This includes lost unpaid work (e.g., household
production) and leisure time for people within and outside the paid
labor force. Implicit in this approach, is that people would pay the
same amount not to be sick during their leisure time as they require to
give up their leisure time to work (i.e., the after tax wage). In
reality, people might be willing to pay either more than this amount
(if they were very sick and suffering a lot) or less than this amount
(if they were not very sick and still got some enjoyment out of
activities such as resting, reading and watching TV), not to be sick.
Multiplying 16 hours by $10.92 gives a value of about $175.00 for a day
of ``lost'' unpaid work and leisure (i.e., lost utility of being sick).
An estimate of lost unpaid work days for the enhanced approach was
made by assigning the value of $10.92 per hour to the same number of
unpaid work hours valued in the traditional COI approach (i.e., 40
unpaid work hours per week for people outside the paid labor force).
Lost unpaid work for employed people and any unpaid labor beyond 40
hours per week for those not in the labor market is shown as lost
leisure time in Table VI-3 for the enhanced approach and is not
included in the traditional approach. In addition, for days when an
individual is well enough to work but still experiencing symptoms, such
as diarrhea, the enhanced estimate also includes a 30% loss of work and
leisure productivity, based on a study of giardiasis illness
(Harrington et al. 1985) which is similar to cryptosporidiosis.
Appendix P in the EA describes similar productivity losses for other
illnesses such as influenza (35%-73% productivity losses). In the
traditional COI analysis, productivity losses are not included for
either work or non-work time.
The Agency believes that losses in productivity and lost leisure
time are unquestionably present and that these categories have positive
value; consequently, the traditional COI estimate understates the true
value of these loss categories. EPA notes that these estimates should
not be regarded as upper and lower bounds. In particular, the enhanced
COI estimate may not fully incorporate the value of pain and suffering,
as people may be willing to pay more than $201 to avoid a day of
illness. The traditional COI estimate includes a valuation for a lost
40 hour work week for all persons not in the labor force, including
children and retirees. This may be an overstatement of lost
productivity for these groups, which would depend on the impact of such
things as missed

[[Page 47742]]

school work or volunteer activities that may be affected by illness.
As with the avoided mortality valuation, the real wages used in the
COI estimates were increased by a real income growth factor that varies
by year, but is the equivalent of about 2.3% over the 20 year period.
This approach of adjusting for real income growth was recommended by
the SAB (USEPA 2000e) because the median real wage is expected to grow
each year (by approximately 2.3%)--the median real wage is projected to
be $38,902 in 2008 and $59,749 in 2027. Correspondingly, the real
income growth factor of the COI estimates increases by the equivalent
of 2.3% per year (except for medical costs, which are not directly tied
to wages). This approach gives a total COI valuation in 2008 of $268.92
for the traditional COI estimate and $931.06 for the enhanced COI
estimate; the valuation in 2027 is $362.75 for the traditional COI
estimate and $1,429.99 for the enhanced COI estimate. There is no
difference in the methodology for calculating the COI over this 20 year
period of implementation; the change in valuation is due to the
underlying change in projected real wages.
Table VI-4 summarizes the annual cases of cryptosporidiosis illness
and associated deaths avoided due to the LT2ESWTR proposal. The
proposed rule, on average, is expected to reduce 256,000 to 1,019,000
illnesses and 37 to 141 deaths annually after full implementation
(range based on the ICRSSL, ICRSSM, and Information Collection Rule
data sets).

Table VI-4.--Summary of Annual Avoided Illness and Deaths
----------------------------------------------------------------------------------------------------------------
Annual illinesses avoided Annual deaths avoided
-----------------------------------------------------------------------------
90 percent confidence 90 percent confidence
Data set bound bound
Mean -------------------------- Mean -------------------------
Lower (5th Upper Lower (5th Upper
%ile) (95th %ile) %ile) (95th %ile)
----------------------------------------------------------------------------------------------------------------
Annual Total After Full Implementation
----------------------------------------------------------------------------------------------------------------
ICR............................... 1,018,915 169,358 2,331,467 141 25 308
ICRSSL............................ 256,173 45,292 560,648 37 7 78
ICRSSM............................ 498,363 84,724 1,177,415 70 13 157
-----------------------------------
Annual Average Over 25 years
----------------------------------------------------------------------------------------------------------------
ICR............................... 720,668 119,694 1,647,796 100 18 218
ICRSSL............................ 181,387 32,179 396,845 26 5 55
ICRSSM............................ 352,611 59,942 833,290 50 9 111
----------------------------------------------------------------------------------------------------------------
Source: The LT2ESWTR Economic Analysis (USEPA 2003a).

Tables VI-5a and VI-5b show the monetized present value of the
benefit for reductions in endemic cryptosporidiosis estimated to result
from the LT2ESWTR for the enhanced and traditional COI values,
respectively. Estimates are given for the Information Collection Rule,
ICRSSL, and ICRSSM occurrence data sets.
With the enhanced COI and a three percent discount rate, the annual
present value of the mean benefit estimate ranges from $374 million to
$1.4 billion, with a 90 percent confidence bound of $52 million to $198
million at the lower 5th percentile and $959 million to $3.7 billion at
the upper 95th percentile; at a seven percent discount rate, this
estimate ranges from $318 million to $1.2 billion, with a 90 percent
confidence bound of $44 million to $168 million at the lower 5th
percentile and $816 million to $3.1 billion at the upper 95th
percentile. With the traditional COI, the corresponding benefit
estimate at a three percent discount rate ranges from $253 million to
$967 million, with a 90 percent confidence bound of $27 million to $105
million at the lower 5th percentile and $713 million to $2.7 billion at
the upper 95th percentile; for a seven percent discount rate, this
estimate ranges from $216 million to $826 million, with a 90 percent
confidence bound of $23 million to $89 million at the lower 5th
percentile and $610 million to $2.3 billion at the upper 95th
percentile. None of these values include the unquantified and non-
monetized benefits discussed previously.

Table VI-5A.--Summary of Quantified Benefits--Enhanced COI
[$millions, 2000$]
----------------------------------------------------------------------------------------------------------------
Value of benefits--Enhanced COI \1\
-----------------------------------------------
90 percent confidence bound
Data set -------------------------------
Mean Lower (5th Upper (95th
%ile) %ile)
----------------------------------------------------------------------------------------------------------------
Annualized Value (at 3%, 25 Years)
----------------------------------------------------------------------------------------------------------------
ICR............................................................. $1,445 $198 3,666
ICRSSL.......................................................... 374 52 959
ICRSSM.......................................................... 715 96 1,849
-----------------------------------------------------------------
Annualized Value (at 7%, 25 Years)
----------------------------------------------------------------------------------------------------------------
ICR............................................................. 1,230 168 3,120

[[Page 47743]]

ICRSSL.......................................................... 318 44 816
ICRSSM.......................................................... 609 81 1,577
----------------------------------------------------------------------------------------------------------------
\1\ The traditional COI only includes valuation for medical costs and lost work time (including some portion of
unpaid household production). The enhanced COI also factors in valuations for lost personal time (non-
worktime) such as child care and homemaking (to the extent not covered by the traditional COI), time with
family, and recreation, and lost productivity at work on days when workers are ill but go to work anyway.
Source: The LT2ESWR Economic Analysis (USEPA 2003a).

Table VI-5b.--Summary of Quantified Benefits--Traditional COI
[($Millions, 2000$]
------------------------------------------------------------------------
Value of Benefits--Traditional
COI \1\
--------------------------------
90 percent
Data Set confidence bound
---------------------
Mean Lower Upper
(5th 95th
%ile) %ile)
------------------------------------------------------------------------
Annualized Value (at 3%, 25 Years)
------------------------------------------------------------------------
ICR.................................... $967 $105 $2,713
ICRSSL................................. 253 27 713
ICRSSM................................. 481 50 1,372
----------------------------------------
Annualized Value (at 7%, 25 Years)
------------------------------------------------------------------------
ICR.................................... 826 89 2,315
ICRSSL................................. 216 23 610
ICRSSM................................. 411 43 1,172
------------------------------------------------------------------------
\1\ The traditional COI only includes valuation for medical costs and
lost work time (including some portion of unpaid household
production). The enhanced COI also factors in valuations for lost
personal time (non-worktime) such as child care and homemaking (to the
extent not covered by the traditional COI), time with family, and
recreation, and lost productivity at work on days when workers are ill
but go to work anyway. Source: The LT2ESWTR Economic Analysis (USEPA
2003a).

a. Filtered systems. Benefits to the approximately 161 million
people served by filtered surface water and GWUDI systems range from
88,000 to 472,000 reduction in mean annual cases of endemic illness
based on ICRSSL, ICRSSM, and ICR data sets. In addition, premature
mortality is expected to be reduced by an average of 9 to 50 deaths
annually.
b. Unfiltered systems. The 12 million people served by unfiltered
surface water or GWUDI systems will see a significant reduction in
cryptosporidiosis as a result of the LT2ESWTR. In this population, the
rule is expected to reduce approximately 168,000 to 547,000 cases of
illness and 28 to 91 premature deaths annually.
For unfiltered systems, only the Information Collection Rule data
set is used to directly calculate illness reduction because it is the
only data set that includes sufficient information on unfiltered
systems. Illness reduction in unfiltered systems was estimated for the
ICRSSL and ICRSSM data sets by multiplying the Information Collection
Rule unfiltered system result by the ratio, for the quantity estimated,
between filtered system results from the supplemental survey data set
(SSM or SSL) and filtered system results from the Information
Collection Rule.
3. Timing of Benefits Accrual (Latency)
In previous rulemakings, some commenters have argued that the
Agency should consider an assumed time lag or latency period in its
benefits calculations. The Agency has not conducted a latency analysis
for this rule because cryptosporidiosis is an acute illness; therefore,
very little time elapses between exposure, illness, and mortality.
However, EPA does account for benefits and costs that occur in future
years by converting these to present value estimates.

D. What Are the Costs of the Proposed LT2ESWTR?

In order to estimate the costs of today's proposed rule, the Agency
considered impacts on public water systems and on States (including
territories and EPA implementation in non-primacy States). EPA assumed
that systems would be in compliance with the IESWTR, which has a
compliance date of January 2002 for large systems and the LT1ESWTR,
which has a compliance date of January 2005 for small systems.
Therefore, this cost estimate only considers the additional
requirements that are a direct result of the LT2ESWTR. More detailed
information on cost estimates are described next and a complete
discussion can be found in chapter 6 of the LT2ESWTR EA (USEPA 2003a).
An detailed discussion of the proposed rule provisions is located in
section IV of this preamble.

[[Page 47744]]

1. Total Annualized Present Value Costs
Tables VI-6a and VI-6b summarize the annualized present value cost
estimates for the proposed LT2ESWTR at three percent and seven percent
discount rates, respectively. The mean annualized present value costs
of the proposed LT2ESWTR are estimated to range from approximately $73
to $111 million using a three percent discount rate and $81 to $121
million using a seven percent discount rate. This range in mean cost
estimates is associated with the ICRSSL and Information Collection Rule
Cryptosporidium occurrence data sets. Using different occurrence data
sets results in different bin classifications and, thus, impacts the
cost of the rule. Results for the ICRSSM fall within the range of
results for the Information Collection Rule and ICRSSL. In addition to
mean estimates of costs, the Agency calculated 90 percent confidence
bounds by considering the uncertainty in Cryptosporidium occurrence
estimates and around the mean unit technology costs (USEPA 2003a).
Public water systems will incur approximately 99 percent of the
rule's total annualized present value costs. States incur the remaining
rule costs. Table VI-7 shows the undiscounted initial capital and one-
time costs broken out by rule component. A comparison of annualized
present value costs among the rule alternatives considered by the
Agency is located in subsection VI.F. and in the LT2ESWTR EA (USEPA
2003a). Using a present value allows costs and benefits that occur
during different time periods to be compared. For any future cost, the
higher the discount rate, the lower the present value. Specifically, a
future cost evaluated at a seven percent discount rate will always
result in a lower total present value cost than the same future cost
evaluated at a three percent discount rate.
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BILLING CODE 6560-50-C
2. Water System Costs
The proposed LT2ESWTR applies to all community, non-transient non-
community, and transient non-community water systems that use surface
water or GWUDI as a source (including both filtered and unfiltered
systems). EPA has estimated the cost impacts for these three types of
public drinking water systems. As shown in Table VI-6a and VI-6b, the
mean annualized present value costs for all drinking water systems
range from approximately $73 to $111 million using a three percent
discount rate ($81 to $121 million using a seven percent discount
rates).
The majority of costs of the rule result from treatment changes
incurred by filtered and unfiltered systems. Table VI-8 shows the
number of filtered and unfiltered systems that will incur costs by rule
provision. Subsection VI.D.2.b discusses treatment costs for filtered
system and subsection VI.D.2.c discusses treatment options for
unfiltered systems. All non-purchased surface water and GWUDI systems
subject to the LT2ESWTR (including filtered and unfiltered systems)
will incur one-time costs that include time for staff training on rule
requirements. Systems will incur monitoring costs to assess source
water Cryptosporidium levels, though monitoring requirements vary by
system size (large vs. small) and system type (filtered vs.
unfiltered). A discussion of future monitoring that will occur six
years after initial bin assignments can be found in subsection
VI.D.2.e.
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BILLING CODE 6560-50-C
a. Source water monitoring costs. Source water monitoring costs are
structured on a per-plant basis. Also, as with implementation
activities, purchased plants are assumed not to treat source water and
will not have any monitoring costs. There are three types of monitoring
that plants may be required to conduct--turbidity, E. coli and
Cryptosporidium. Source water turbidity is a common water quality
parameter used for plant operational control. Also, to meet SWTR,
LT1ESWTR and IESWTR requirements, most water systems have turbidity
analytical equipment in-house and operators are experienced with
turbidity measurement. Thus, EPA assumes that the incremental turbidity
monitoring burden associated with the LT2ESWTR is negligible.
Filtered plants in small systems initially will be required to
conduct one year of biweekly E. coli source water monitoring. These
plants will be required to monitor for Cryptosporidium if, as a result
of initial bin classification, E. coli levels exceed the following
concentrations: (1) Annual mean 10 E. coli/100 mL for lakes
and reservoir sources, and (2) annual mean 50 E. coli/100
mL for flowing stream sources. EPA estimated the percent of small
plants that would be triggered into Cryptosporidium monitoring as being
equal to the percent of large plants that would fall into any bin
requiring additional treatment.
Estimates of laboratory fees, shipping costs, labor hours for
sample collection, and hours for reporting results were used to predict
system costs for initial source water monitoring under the LT2ESWTR.
Table VI-9 summarizes the present value of monitoring costs for initial
bin classification. Total present value monitoring costs for initial
bin classification range from $46 million to $60 million depending on
the occurrence data set and discount rate. Appendix D of the LT2ESWTR
EA provides a full explanation of how these costs were developed (USEPA
2003a).

[[Page 47749]]

Table VI-9.--Summary of Present Value Monitoring Costs for Initial Bin Classification
($millions, 2000$)
--------------------------------------------------------------------------------------------------------------------------------------------------------
System Size ICR (3%) A ICR (7%) B ICRSSL (3%) C ICRSSL (7%) D ICRSSM (3%) E ICRSSM (7%) F
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=10K......................................................... $34.6 $29.7 $25.7 $22.2 $29.2 $25.1
10K........................................................... 25.7 24.3 25.7 24.3 25.7 24.3
--------------
Total..................................................... 60.3 54.0 51.4 46.5 54.9 49.4
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: Chapter 6 of the LT2ESWTR Economic Analysis (USEPA 2003a).

b. Filtered systems treatment costs. The Agency calculated
treatment costs by estimating the number of plants that will be adding
treatment technologies and coupling these estimates with unit costs ($/
plant) of the selected technologies. Table VI-10 shows the number of
plants estimated to select different treatment technologies; Table VI-
11 summarizes the present value treatment costs and annualized present
value costs for both filtered and unfiltered systems.
To estimate the number of filtered plants that would select a
particular treatment technology, the Agency followed a two step
process. First, the number of plants that must make treatment changes
to meet the proposed LT2ESWTR requirement was determined by the binning
process. Second, EPA predicted the treatment technologies that plants
would choose to meet the proposed requirements. The Agency used a
``least-cost decision tree'' as the basic framework for determining the
treatment technology selection. In other words, EPA assumed that
drinking water plants would select the least expensive technology or
combination of technologies to meet the log removal requirements of a
given action bin. However, these technology selections were constrained
by maximum use percentages, which recognize that some plants will not
be able to implement certain technologies because of site-specific
conditions. In addition, certain potentially lower cost components of
the microbial toolbox, such as changes to the plant intake, were not
included because the Agency lacked data to estimate the number of
plants that could select it. These limitations on technology use may
result in an overestimate of costs. An in-depth discussion of the
technology selection methodology and unit cost estimates can be found
in appendices E and F of the proposed LT2ESWTR EA (USEPA 2003a).

Table VI-10.--Technology Selection Forecasts for Filtered Plants
----------------------------------------------------------------------------------------------------------------
Data set
--------------------------------
ICR ICRSSL ICRSSM
----------------------------------------------------------------------------------------------------------------
Technology Selections

Bag Filter 1.0 Log............................................................. 1,545 1,236 1,441
Cartridge Filter 2.0 Log....................................................... 190 17 52
CL02 0.5 Log................................................................... 77 60 70
Combined Filter Performance 0.5 Log............................................ 16 12 14
In-bank Filtration 1.0 Log..................................................... 5 3 4
MF/UF 2.5 Log.................................................................. 10 3 5

Technology Selections \1\

03 0.5 Log..................................................................... 26 17 21
03 1.0 Log..................................................................... 24 18 21
03 2.0 Log..................................................................... 9 1 2
Secondary Filter 1.0 Log....................................................... 0 0 0
UV 2.5 Log..................................................................... 998 490 632
WS Control 0.5 Log............................................................. 0 0 0
Total Plants Selecting Technologies........................................ 2,893 1,852 2,255
----------------------------------------------------------------------------------------------------------------
\1\ Some plants are projected to select more than one technology to meet LT2ESWTR bin requirements;
consequently, the value for total plants does not equal the sum of all technologies selected. Source: Chapter
6 of the LT2ESWTR Economic Analysis (USEPA 2003a).

c. Unfiltered systems treatment costs. The proposed LT2ESWTR
requires all unfiltered plants to achieve 2 logs of inactivation if
their mean source water Cryptosporidium concentration is less than or
equal to 0.01 oocysts/L and 3 logs of inactivation if it is greater
than 0.01 oocysts/L. For most systems, UV appears to be the least
expensive technology that can achieve the required log inactivation of
Cryptosporidium, and it is expected to be widely used by unfiltered
systems to meet the rule requirement. However, as with filtered
systems, EPA estimated that a small percentage of plants would elect to
install a technology more expensive than UV due to the configuration of
existing equipment or other factors. Ozone is the next least expensive
technology that will meet the inactivation requirements for some
systems, and is estimated to be used by plants that do not use UV.
All unfiltered plants must meet requirements of the LT2ESWTR;
therefore, the percent of plants adding technology is 100 percent. This
also assumes that no unfiltered systems currently use these additional
treatment technologies. For this cost analysis, the Agency assumed 100
percent of very small unfiltered systems will use UV; for all other
unfiltered system sizes, the Agency estimated that 90 percent would
install UV and 10 percent would add ozone. This analysis is discussed
in more detail in the LT2ESWTR EA (USEPA 2003a). Treatment costs for
unfiltered systems are included in Table VI-11.

[[Page 47750]]

Table VI-11.--Total Present Value and Annualized Present Value Treatment Costs for Filtered and Unfiltered Plants
--------------------------------------------------------------------------------------------------------------------------------------------------------
Present Present
System Size Value Value Annualized Annualized Total Total
Data Set (population Capital Capital O&M Costs O&M Costs Annuallized Annualized
served) Costs at 3% Costs at 7% at 3% C at 7% D Costs at 3% Costs at 7%
A B E F
--------------------------------------------------------------------------------------------------------------------------------------------------------
ICR....................................................... <=10,000 $76.1 $56.0 $5.2 $4.3 $9.6 $9.1
10, 1,092.4 868.0 26.1 22.7 88.8 97.1
000
TOTAL................................................. .............. 1,168.5 924.0 31.3 26.9 98.4 106.2
--------------
ICRSSL.................................................... <=10,000 42.8 31.5 2.9 2.4 5.3 5.1
10, 707.1 561.8 16.2 14.0 56.8 62.3
000
TOTAL................................................. .............. 749.8 593.3 19.0 16.4 62.1 67.3
--------------
ICRSSM.................................................... <=10,000 52.6 38.7 3.5 2.9 6.6 6.2
10, 842.4 669.3 19.4 16.9 67.8 74.3
000
TOTAL................................................. .............. 894.9 708.0 23.0 19.8 74.4 80.6
--------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: Chapter 6 of the LT2ESWTR Economic Analysis (USEPA 2003a)

d. Uncovered finished water storage facilities. As part of the
LT2ESWTR, systems with uncovered finished water storage facilities have
the option to cover the storage facility or provide disinfection after
the storage facility, unless the State has determined that existing
risk mitigation is adequate. Disinfection alternatives must achieve at
least four logs of virus inactivation. To develop national cost
estimates for systems to comply with this provision of the LT2ESWTR,
unit costs for each treatment alternative and the percentage of systems
selecting each alternative were estimated for the inventory of systems
with uncovered finished water storage facilities. A full description of
the unit costs and other assumptions used in this analysis is presented
in Chapter 6 and Appendix I of the LT2ESWTR EA (USEPA 2003a).
The Agency assumed that all systems with uncovered finished water
storage facilities will have to either install a cover or treat their
discharge. This overestimates the cost of this provision because States
can determine that systems with uncovered finished storage facilities
do not need to take these additional measures. The technology selection
for the uncovered finished water storage facilities was developed
through a least-cost approach.
For systems with uncovered storage facility capacities of five
million gallons (MG) or less, covering the storage facilities is the
least expensive alternative. Although chlorination is the least
expensive alternative for the remaining systems, the ability of a
system to use booster chlorination depends on their current residual
disinfectant type. Less than half of all surface water systems are
predicted to use chloramination following implementation of the Stage 2
DBPR. Adding chlorine to water that has been treated with chloramines
is not a feasible alternative; therefore, the fraction of systems
projected to add booster chlorination to the effluent from the storage
facility was estimated at 50 percent, with the remaining 50 percent
estimated to add covers. The technology selection for uncovered
finished water storage facilities is presented in Table VI-12.

Table VI-12.--Estimated Technology Selection for Uncovered Storage Facilities
----------------------------------------------------------------------------------------------------------------
Number of uncovered Floating Booster
Size category (MG) storage facilities cover (%) chlorination (%)
----------------------------------------------------------------------------------------------------------------
0-0.1................................................ 25 100 ..................
0.1-1................................................ 7 100 ..................
1-5....................................... 44 100 ..................
5-10...................................... 12 100 ..................
10-20..................................... 10 100 ..................
20-40..................................... 9 50 50
40-60..................................... 4 50 50
60-80..................................... 4 50 50
80-100.................................... 6 50 50
100-150................................... 6 50 50
150-200................................... 2 50 50
200-250................................... 4 50 50
250-1,000................................. 4 50 50
1,000..................................... 1 50 50
----------------------------------------------------------------------------------------------------------------
Source: Appendix I of the LT2ESWTR Economic Analysis (USEPA 2003a)

Table VI-13 summarizes total annualized present value costs for the
uncovered storage facility provision using both three and seven percent
discount rates. The Agency estimates the total annualized present value
cost for covering or treating uncovered finished water storage
facilities to be approximately $5.4 million at a three percent discount
rate and $6.4 million at a seven percent discount rate.

[[Page 47751]]

Table VI-13.--Estimated Annualized Present Value Cost for Uncovered Finished Water Storage Facility Provision
(2000$)
----------------------------------------------------------------------------------------------------------------
Annualized cost at 3% Annualized cost at 7%
System size (population served) ------------------------------------------------------------------------------
Capital O&M Total Capital O&M Total
----------------------------------------------------------------------------------------------------------------
<=10,000......................... $3,520 $1,649 $5,169 $4,713 $1,552 $6,264
10,000................ 3,349,320 2,046,425 5,395,745 4,483,927 1,925,203 6,409,129
----------------------------------
Total...................... 3,352,840 2,048,074 5,400,915 4,488,639 1,926,754 6,415,393
----------------------------------------------------------------------------------------------------------------
Source: Appendix I of the LT2ESWTR Economic Analysis (USEPA 2003a)

e. Future monitoring costs. Six years after initial bin
classification, filtered and unfiltered plants will be required to
conduct a second round of monitoring to assess whether source water
Cryptosporidium levels have changed significantly. EPA will evaluate
new analytical methods and surrogate indicators of microbial water
quality in the interim. While the costs of monitoring are likely to
change in the six years following rule promulgation, it is difficult to
predict how they will change. In the absence of any other information,
it was assumed that the laboratory costs would be the same as for the
initial monitoring.
All plants that conducted initial monitoring were assumed to
conduct the second round of monitoring as well, except for those
systems that installed treatment that reduces 2.5 logs of
Cryptosporidium or greater as a result of the rule. These systems are
exempt from monitoring under the LT2ESWTR. Table VI-8 shows the number
of systems that are estimated to conduct the second round of monitoring
(listed as ``future'' monitoring in the table). EPA estimates the cost
of re-binning will range from $23 million to $38 million depending on
the occurrence data set and discount rate used in the estimate (see
Table VI-14). Costs differ among Cryptosporidium occurrence data sets
due to differences in estimates of the number of plants that will add
technologies to achieve at least 2.5 log Cryptosporidium reduction and
the number of small plants that will be triggered into monitoring for
Cryptosporidium. Appendix D of the EA provides further details (USEPA
2003a).

Table VI-14.--Present Value of Monitoring Costs of Future Re-binning
[$millions, 2000$]
----------------------------------------------------------------------------------------------------------------
ICR (3%) ICR (7%) ICRSSL ICRSSL ICRSSM ICRSSM
-------------------- (3%) (7%) (3%) (7%)
System size ---------------------------------------
A B C D E F
----------------------------------------------------------------------------------------------------------------
<=10K............................................... $23.5 $14.3 $18.4 $11.3 $20.7 $12.6
10k...................................... 14.4 9.8 16.4 11.2 15.6 10.7
Total......................................... 37.8 24.1 34.8 22.5 36.3 23.3
----------------------------------------------------------------------------------------------------------------
Source: Chapter 6 of the LT2ESWTR Economic Analysis (USEPA 2003a)

f. Sensitivity analysis--influent bromide levels on technology
selection for filtered plants. One concern about the ICR data set was
that it may not actually reflect influent bromide levels in some plants
during droughts. High influent bromide levels (the precursor for
bromate formation) limits ozone use because the plant would not be able
to meet the MCL for bromate. The Agency conducted a sensitivity
analysis to estimate an impact of higher influent bromide levels would
have on technology decisions. The sensitivity analysis assumes influent
bromide concentrations of 50 parts per billion (ppb) above the ICR
concentrations. Overall, the impact of these assumptions have a minimal
impact on costs. A complete discussion of this sensitivity analysis is
located in LT2ESWTR EA (USEPA 2003a).
3. State/Primacy Agency Costs
The Agency estimates that States and primacy agencies will incur an
annualized present value cost of $0.9 to $1.0 million using a three
percent discount rate and $1.2 million at seven percent. State
implementation activities include regulation adoption and program
implementation, training State staff, training PWS staff, providing
technical assistance to PWSs, and updating the management system. To
estimate implementation costs to States/Primacy Agencies, the number of
full-time employees (FTEs) per activity is multiplied by the number of
labor hours per FTE, the cost per labor hour, and the number of States
and Territories.
In addition to implementation costs, States and primacy agencies
will also incur costs associated with monitoring data management.
Because EPA will directly manage the first round of monitoring by large
systems (serving at least 10,000 people), States are not predicted to
incur costs for these activities. States will, however, incur costs
associated with small system monitoring. This is a result of the
delayed start of small system monitoring, which will mean that some
States will assume primacy for small system monitoring. In addition,
States will review of the second round of monitoring results. States
will also incur costs in reviewing technology compliance data and
consulting with systems regarding benchmarking for systems that change
their disinfection procedures to comply with the rule. Appendix D of
the LT2ESWTR EA provides more information about the State and primacy
agency cost analysis (USEPA 2003a).
4. Non-Quantified Costs
EPA has quantified all the major costs for this rule and has
provided uncertainty analyses to bound the over or underestimates in
the costs. There are some costs that EPA has not quantified, however,
because of lack of data. For example, some systems may merge with
neighboring systems to comply with this rule. Such changes have both
costs (legal fees and connecting infrastructure) and benefits
(economies of scale). Likewise, systems would incur

[[Page 47752]]

costs for procuring a new source of water that may result in lower
overall treatment costs.
In addition, the Agency was unable to predict the usage or estimate
the costs of several toolbox options. These options include intake
management and demonstrations of performance. They have not been
included in the quantified analysis because data are not available to
estimate the number of systems that may use these toolbox options to
comply with the LT2ESWTR. Not including these generally low-cost
options may result in overestimation of costs.

E. What Are the Household Costs of the Proposed Rule?

Another way to assess a rule's impact is to consider how it might
impact residential water bills. This analysis considers the potential
increase in a household's water bill if a CWS passed the entire cost
increase resulting from this rule on to its customers. It is a tool to
gauge potential impacts and should not be construed as precise
estimates of potential changes to individual water bills.
Included in this analysis are all CWS costs, including rule
implementation, initial and future monitoring for bin classification,
additional Cryptosporidium treatment, and treating or covering
uncovered finished water storage facilities. Costs for small systems
Cryptosporidium monitoring, additional Cryptosporidium treatment, and
uncovered finished water storage facilities are assigned only to the
subset of systems expected to incur them. Although implementation and
monitoring represent relatively small, one-time costs, they have been
included in the analysis to provide a complete distribution of the
potential household cost. A detailed description of the derivation of
household costs is in section 6.10 and Appendix J of the LT2ESTWR EA
(USEPA 2003a).
For purchased systems that are linked to larger nonpurchased
systems, the households costs are calculated based on the unit costs of
the larger system but included in the distribution from the size
category of the purchased system. Households costs for these purchased
systems are based on the household usage rates appropriate for the
retail system and not the system selling the water. This approach for
the purchased systems reflects the fact that although they will not
face increased costs from adding their own treatment, whatever costs
the wholesale utility incurs would likely be passed on as higher water
costs.
Table VI-15 shows the results of the household cost analysis. In
addition to mean and median estimates, the Agency calculated the 90th
and 95th percentile. EPA estimates that all households served by
surface and GWUDI sources will face some increase in household costs
due to implementation of the LT2ESWTR (except for those few served by
systems that have already installed 5.5 logs of treatment for
Cryptosporidium). Of all the households subject to the rule, from 24 to
35 percent are projected to incur costs for adding treatment, depending
on the Cryptosporidium occurrence data set used.
Approximately 95 percent of the households potentially subject to
the rule are served by systems serving at least 10,000 people; these
systems experience the lowest increases in costs due to significant
economies of scale. Over 90 percent of all households will face an
annual cost increase of less than $5. Households served by small
systems that install advanced technologies will face the greatest
increases in annual costs. EPA expects that the model's projections for
these systems are, in some cases, overstated. Some systems are likely
to find alternative treatment techniques such as other toolbox options
not included in this analysis, or sources of water (ground water,
purchased water, or consolidating with another system) that would be
less costly than installing more expensive treatment techniques.

Table VI-15.--Potential Annual Household Costs Impacts for the Preferred Regulatory Option (2000$)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Percent of Percent of
systems with systems with
System: type/size Households Mean Median 90th 95th household household
Percentile Percentile cost increase cost increase
< $12 < $120
--------------------------------------------------------------------------------------------------------------------------------------------------------
All Systems--ICR
--------------------------------------------------------------------------------------------------------------------------------------------------------
All CWS................................. 65,816,979 $1.68 $0.13 $4.06 $7.57 98.37 99.99
CWS <= 10,000........................... 3,318,012 4.61 1.34 13.04 14.92 87.88 99.88
-----------------------------------------
All Systems--ICRSSL
--------------------------------------------------------------------------------------------------------------------------------------------------------
All CWS................................. 65,816,979 $1.07 $0.03 $3.24 $5.43 98.31 100.00
CWS <= 10,000........................... 3,318,012 2.68 0.80 6.10 9.39 95.71 99.95
-----------------------------------------
All Systems--ICRSSM
--------------------------------------------------------------------------------------------------------------------------------------------------------
All CWS................................. 65,816,979 $1.28 $0.03 $3.48 $6.47 99.07 100.00
CWS <= 10,000........................... 3,318,012 3.27 0.80 6.62 13.04 93.90 99.93
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: Chapter 6 of the LT2ESWTR Economic Analysis (USEPA 2003a).

F. What Are the Incremental Costs and Benefits of the Proposed
LT2ESWTR?

Incremental costs and benefits are those that are incurred or
realized in reducing Cryptosporidium exposures from one alternative to
the next. Estimates of incremental costs and benefits are useful in
considering the economic efficiency of different regulatory options
considered by the Agency. Generally, the goal of an incremental
analysis is to identify the regulatory option where incremental
benefits most closely equal incremental costs. However, the usefulness
of this analysis is limited because many benefits from this rule are
unquantified and not monetized. Incremental analyses should consider
both quantified and non-quantified (where possible) benefits and costs.
Usually an incremental analysis implies increasing levels of
stringency along a single parameter, with each alternative providing
all the protection of the previous alternative, plus additional
protection. However, the

[[Page 47753]]

regulatory alternatives in this rule vary by multiple parameters (e.g,
risk bin boundaries, treatment requirements). The comparison between
any two alternatives is, therefore, between two separate sets of
benefits, in the sense that they may be distributed to somewhat
different population groups.
The regulatory alternatives, however, do achieve increasing levels
of benefits at increasing levels of costs. As a result, it is possible
to display incremental net benefits from the baseline and alternative
to alternative. Tables VI-16a and VI-16b show incremental costs,
benefits, and net benefits for the four regulatory alternatives shown
in Table VI-1, using the enhanced and traditional COI, respectively.
All values are annualized present values expressed in Year 2000
dollars. The displayed values are the mean estimates for the different
occurrence distributions.
With the enhanced COI, incremental costs are generally closest to
incremental benefits for A2, a more stringent alternative than the
Preferred Alternative, A3. For the traditional COI, incremental costs
most closely equal incremental benefits for A3, the Preferred
Alternative, under the majority of conditions evaluated.
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G. Are There Benefits From the Reduction of Co-Occurring Contaminants?

This section presents information on the unquantified benefits that
will accrue from removal of other contaminants, primarily pathogens,
due to improved control of Cryptosporidium. While the benefits analysis
for the LT2ESWTR only includes reductions in illness and mortality
attributable to Cryptosporidium, the LT2ESWTR is expected to reduce
exposure to other parasitic protozoans that EPA regulates, or is
considering for future regulation. For example, it is expected that the
LT2ESWTR will improve control of Giardia lamblia, Cyclospora sp. and
members of the Microsporididea class, seven genera (10 species) of
which have been recovered in humans (Mota et al., 2000). In addition,
greater Cryptosporidium control may improve control of the pathogenic
bacteria and viruses. Chemical contaminants such as arsenic, DBPs and
atrazine may also be controlled, in part, by control of
Cryptosporidium, depending on the technologies selected.
Giardia lamblia and Cyclospora sp. are larger than Cryptosporidium,
while Microsporididea, bacteria, and the viruses are smaller than
Cryptosporidium. The expected removal of co-occurring microorganisms
can often be predicted for those treatment unit processes whose removal
efficiency

[[Page 47755]]

depends in part, or entirely, on the size of the organism. For example,
a study by Goodrich and Lykins (1995) evaluating bag filters showed
that any microbe or object greater than 4.5 microns in size (the
average size of Cryptosporidium) would be subject to removal ranging
from 0.5 to 2.0 logs.
Although not directly dependent on organism size, other treatment
technologies identified in the LT2ESWTR should also provide additional
control of co-occurring microbial pathogens. Membrane processes that
remove Cryptosporidium are shown to achieve equivalent log removal of
Giardia under worst-case and normal operating conditions (USEPA 2003c).
Reduction in individual filter turbidities will reduce concentrations
of other pathogens as well as Cryptosporidium. For example, in Dutch
surface water, Giardia and Cryptosporidium occurrence appeared to
correlate well with each other and for the Rhine River, with turbidity
(Medema et al. 2001). Thus, improved control of Cryptosporidium should
also result in improved control of Giardia lamblia.
Some membrane technologies that might be installed to comply with
the LT2ESWTR can also reduce or eliminate chemical contaminants
including arsenic, DBPs and atrazine. EPA has recently finalized a rule
to further control arsenic levels in drinking water and is concurrently
proposing the Stage 2 DBPR to address DBP control.
The extent to which the LT2ESWTR can reduce the overall risk from
other contaminants has not been quantitatively evaluated because of the
Agency's lack of data regarding the co-occurrence among Cryptosporidium
and other microbial pathogens and contaminants. Because of the
difficulties in establishing which systems would have multiple
problems, such as microbial contamination, arsenic, and DBPs or any
combination of the three, no estimate was made of the potential cost
savings from addressing more than one contaminant simultaneously.

H. Are There Increased Risks From Other Contaminants?

It is unlikely that the LT2ESWTR will result in a significant
increase in risk from other contaminants. Many of the options that
systems will select to comply with the LT2ESWTR, such as UV, improved
filtration performance, and watershed control, do not form DBPs. Other
technologies that are effective against Cryptosporidium, such as ozone
and chlorine dioxide, do form DBPs. However, these DBPs are currently
regulated under the Stage 1 DBPR, and systems will have to comply with
these regulations when implementing technologies to meet the LT2ESWTR.

I. What Are The Effects of the Contaminant on the General Population
and Groups Within the General Populations That Are Identified as Likely
To Be at Greater Risk of Adverse Health Effects?

Section II of this preamble discusses the health effects associated
with Cryptosporidium on the general population as well as the effects
on other sensitive sub-populations. In addition, health effects
associated with children and pregnant women are discussed in greater
detail in section VII.G of this preamble.

J. What Are the Uncertainties in the Baseline, Risk, Benefit, and Cost
Estimates for the Proposed LT2ESWTR as Well as the Quality and Extent
of the Information?

Today's proposal models the current baseline risk from
Cryptosporidium exposure, as well as the reduction in risk and the cost
for various rule options. There is uncertainty in the risk calculation,
the benefit estimate, the cost estimates, and the interaction of other
upcoming rules. Section IV of the proposed rule considers the
uncertainty with the risk estimates; however, a brief summary of the
major risk uncertainties as they relate to benefit estimation is
provided next. In addition, the LT2ESWTR EA has a more extensive
discussion of all of the uncertainties (USEPA 2003a).
In addition, the Agency conducted sensitivity analyses to address
uncertainty. The sensitivity analyses focus on various occurrence,
benefit and cost factors that may have a significant effect on the
estimated impacts of the rule. All of these sensitivity analyses are
explained in more detail in the EA for the LT2ESWTR (USEPA 2003a).
One area of uncertainty is associated with the estimate of
Cryptosporidium occurrence on a national basis. The Information
Collection Rule plant-mean data were higher than the ICRSS medium or
large system plant-mean data at the 90th percentile. The reasons for
these differing results are not well understood but may stem from
differences in the populations sampled, year-to-year variation in
occurrence, and systematic differences in the sampling and measurement
methods employed. These data suggest that Cryptosporidium levels are
relatively low in most water sources, but there is a subset of sources
with significantly higher concentrations. Additional uncertainty is
associated with estimating finished water occurrence because the
analysis is based on assumptions about treatment plant performance. To
account for these uncertainties, the Agency used Monte Carlo simulation
models that allow substantial variation in each estimate and computed
finished water occurrence values based on statistical sampling of the
variable estimates.
The risk associated with finished water occurrence is of lesser
uncertainty than is typical for many contaminants because the health
effects are measured based on Cryptosporidium challenge studies to
human volunteer populations. Nevertheless, there is significant
uncertainty about the dose-response associated with Cryptosporidium
because there exists considerable differences in infectivity among the
various tested Cryptosporidium parvum isolates. As described in section
III.B, the Agency accounted for these differences using Monte Carlo
simulations that randomly sampled from infectivity distributions for
the three tested isolates. The different simulations were designed to
account for the limited number of challenge studies and the variability
in the infectivity of the isolates themselves. In addition, because the
Cryptosporidium dosing levels in the human feeding studies were above
typical drinking water exposure levels (e.g., one oocyst), there
remains significant uncertainty that could not be quantified into the
analysis.
While all of the significant costs of today's proposed rule have
been identified by EPA, there are uncertainties about some of the
estimates. However, the Agency explored the impact of the uncertainties
that might have the greatest impact by conducting sensitivity analyses
and using Monte Carlo techniques. For example, section VI.D.2.f of
today's rule explores the impact of influent bromide levels on
technology selection. As shown in the EA for this rule, the impact of
higher influent bromide levels will not have a significant impact on
the rule's costs. In addition, subsection 6.12 of the EA summarizes
other cost uncertainties including the Agency's inability to include
some lower cost toolbox options in the cost analysis (USEPA 2003a).
Last, EPA has recently finalized new regulations for arsenic,
radon, Cryptosporidium in small surface water systems, and filter
backwash in all system sizes (LT1ESWTR and Filter Backwash Rule);
proposed a rule for microbials in ground water systems (Ground Water
Rule); and is

[[Page 47756]]

concurrently proposing additional control of disinfection byproducts
(Stage 2 Disinfection Byproducts Rule). These rules may have
overlapping impacts on some drinking water systems but the extent is
not possible to estimate because of lack of information on co-
occurrence. However, it is possible for a system to choose treatment
technologies that would address multiple contaminants. Therefore, while
the total cost impact of these drinking water rules is uncertain, it is
most likely less than the estimated total cost of all individual rules
combined.

K. What is the Benefit/Cost Determination for the Proposed LT2ESWTR?

The Agency has determined that the benefits of the proposed
LT2ESWTR justify the costs. As discussed in section VI.C, the proposed
rule provides a large reduction in endemic cryptosporidiosis illness
and mortalities. More stringent alternatives provide greater reductions
but at higher costs. Alternative A1 provides the greatest overall
reduction in illnesses and mortalities but the incremental benefits
between this option and the preferred option are relatively small while
the incremental costs are significant. In addition, the preferred
regulatory option, unlike option A1, specifically targets those systems
whose source water requires higher levels of treatment.
Tables VI-17a and VI-17b present net benefits for the four
regulatory alternatives that were evaluated. Generally, analysis of net
benefits is used to identify alternatives where benefits exceed costs,
as well as the alternative that maximizes net benefits. However, as
with the analysis of incremental net benefits discussed previously, the
usefulness of this analysis in evaluating regulatory alternatives for
the LT2ESWTR is limited because many benefits from this rule are un-
quantified and non-monetized. Analyses of net benefits should consider
both quantified and non-quantified (where possible) benefits and costs.
Also, as noted earlier, the regulatory alternatives considered for
the LT2ESWTR vary both in the population that experiences benefits and
costs (i.e., risk bin boundaries) and the magnitude of the benefits and
costs (i.e., treatment requirements). Consequently, the more stringent
regulatory alternatives provide benefits to population groups that do
not experience any benefit under less stringent alternatives.
As shown by Tables VI-17a and VI-17b, net benefits are positive for
all four regulatory alternatives evaluated. With the enhanced COI
(Table VI-17a), net benefits are highest for the Preferred Alternative,
A3, under the majority of occurrence distributions and discount rates
evaluated. When the traditional COI (Table VI-17b) is used, the
Preferred Alternative has the highest net benefits at a three percent
discount rate for the two of the occurrence distributions, the
Information Collection Rule and ICRSSM, while the least stringent
alternative, A4, is highest for the ICRSSL. At a seven percent discount
rate, A4 maximizes net benefits under all occurrence distributions.

Table VI-17a.-- Mean Net Benefits by Rule Option--Enhanced COI
($millions, 2000$)

[[Page 47757]]

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BILLING CODE 6560-50-C
In addition to the net benefits of the proposed LT2ESWTR, the
Agency used several other techniques to compare costs and benefits. For
example, EPA calculated the cost of the rule per case avoided. Table
VI-18 shows both the cost of the rule per illness avoided and cost of
the rule per death avoided. This cost effectiveness measure is another
way of examining the benefits and costs of the rule but should not be
used to

[[Page 47758]]

compare alternatives because an alternative with the lowest cost per
illness/death avoided may not result in the highest net benefits. With
the exception of alternative A1, the rule options look favorable from a
cost effectiveness analysis when you compare them to both the average
cost of cryptosporidiosis illness ($745 and $245 for the two COI
approaches) and the mean value of a death avoided--approximately $7
million dollars. Additional information about this analysis and other
methods of comparing benefits and costs can be found in chapter 8 to
the LT2ESWTR EA (USEPA 2003a).

Table VI-18.--Cost Per Illness or Death Avoided
----------------------------------------------------------------------------------------------------------------
Cost per illness Cost per death
avoided ($) avoided ($
Data set Rule alternative ------------------ millions, 2000$)
-----------------
3% 7% 3% 7%
----------------------------------------------------------------------------------------------------------------
A1............................ 339 244 2.5 1.8
A2............................ 128 93 0.9 0.7
ICR......................................... A3--Preferred................. 107 78 0.8 0.6
A4............................ 62 45 0.4 0.3
---------------------------------------------
A1............................ 1,098 789 8.0 5.7
A2............................ 356 259 2.5 1.8
ICRSSL...................................... A3--Preferred................. 282 208 1.9 1.4
A4............................ 165 122 1.1 0.8
---------------------------------------------
A1............................ 631 453 4.6 3.3
A2............................ 213 155 1.6 1.1
ICRSSM...................................... A3--Preferred................. 170 125 1.2 0.9
A4............................ 99 73 0.7 0.5
----------------------------------------------------------------------------------------------------------------
Source: Chapter 8 of the LT2ESWTR Economic Analysis (USEPA 2003a)

L. Request for Comment

The Agency requests comment on all aspects of the proposed rule's
economic impact analysis. Specifically, EPA seeks input into the
following issues:
[sbull] Both of the methodologies for valuing non-fatal
cryptosporidiosis and the use of a real income growth factor to adjust
these estimates for the years 2008 through 2027;
[sbull] How can the Agency fully incorporate all toolbox options
into the economic analysis?
[sbull] How can the Agency estimate the potential benefits from
reduced epidemic outbreaks of cryptosporidiosis?

VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

Under Executive Order 12866, (58 FR 51735, October 4, 1993) the
Agency must determine whether the regulatory action is ``significant''
and therefore subject to OMB review and the requirements of the
Executive Order. The Order defines ``significant regulatory action'' as
one that is likely to result in a rule that may:
(1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or Tribal governments or
communities;
(2) Create a serious inconsistency or otherwise interfere with an
action taken or planned by another agency;
(3) Materially alter the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
(4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
Pursuant to the terms of Executive Order 12866, it has been
determined that this rule is a ``significant regulatory action.'' As
such, this action was submitted to OMB for review. Changes made in
response to OMB suggestions or recommendations will be documented in
the public record.

B. Paperwork Reduction Act

The information collection requirements in this proposed rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The
Information Collection Request (ICR) document prepared by EPA has been
assigned EPA ICR number 2097.01.
The information collected as a result of this rule will allow the
States and EPA to determine appropriate requirements for specific
systems, and to evaluate compliance with the rule. For the first 3
years after LT2ESWTR promulgation, the major information requirements
concern monitoring activities and compliance tracking. The information
collection requirements are mandatory (part 141), and the information
collected is not confidential.
The estimate of annual average burden hours for the LT2ESWTR during
the first three years following promulgation is 145,854 hours. The
annual average cost estimate is $3.9 million for labor and $9.8 million
per year for operation and maintenance including lab costs (which is a
purchase of service). The burden hours per response is 1.47 hours and
the cost per response is $138.12. The frequency of response (average
responses per respondent) is 39, annually. The estimated number of
likely respondents is 2,560 (the product of burden hours per response,
frequency, and respondents does not total the annual average burden
hours due to rounding). Note that the burden hour estimates for the
first 3-year cycle include large system but not small system
monitoring. Conversely, burden estimate for the second 3-year cycle
will include small system monitoring but not large system, which will
have been completed by then.
Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal agency. This includes the time
needed to review instructions; develop, acquire, install, and utilize
technology

[[Page 47759]]

and systems for the purposes of collecting, validating, and verifying
information, processing and maintaining information, and disclosing and
providing information; adjust the existing ways to comply with any
previously applicable instructions and requirements; train personnel to
be able to respond to a collection of information; search data sources;
complete and review the collection of information; and transmit or
otherwise disclose the information.
An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations in 40 CFR are listed in 40 CFR part 9.
To comment on the Agency's need for this information, the accuracy
of the provided burden estimates, and any suggested methods for
minimizing respondent burden, including the use of automated collection
techniques, EPA has established a public docket for this rule, which
includes this ICR, under Docket ID No. OW-2002-0039. Submit any
comments related to the ICR for this proposed rule to EPA and OMB. See
Addresses section at the beginning of this notice for where to submit
comments to EPA. Send comments to OMB at the Office of Information and
Regulatory Affairs, Office of Management and Budget, 725 17th Street,
NW., Washington, DC 20503, Attention: Desk Office for EPA. Since OMB is
required to make a decision concerning the ICR between 30 and 60 days
after August 11, 2003, a comment to OMB is best assured of having its
full effect if OMB receives it by September 10, 2003. The final rule
will respond to any OMB or public comments on the information
collection requirements contained in this proposal.

C. Regulatory Flexibility Act

The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis for any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions.
The RFA provides default definitions for each type of small entity.
It also authorizes an agency to use alternative definitions for each
category of small entity, ``which are appropriate to the activities of
the agency'' after proposing the alternative definition(s) in the
Federal Register and taking comment. 5 U.S.C. secs. 601(3)-(5). In
addition to the above, to establish an alternative small business
definition, agencies must consult with SBA's Chief Council for
Advocacy.
For purposes of assessing the impacts of today's proposed rule on
small entities, EPA considered small entities to be public water
systems serving 10,000 or fewer persons. This is the cut-off level
specified by Congress in the 1996 Amendments to the Safe Drinking Water
Act for small system flexibility provisions. In accordance with the RFA
requirements, EPA proposed using this alternative definition in the
Federal Register, (63 FR 7620, February 13, 1998), requested public
comment, consulted with the Small Business Administration (SBA), and
expressed its intention to use the alternative definition for all
future drinking water regulations in the Consumer Confidence Reports
regulation (63 FR 44511, August 19, 1998). As stated in that final
rule, the alternative definition is applied to this proposed
regulation.
After considering the economic impacts of today's proposed rule on
small entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities. We have
determined that 274 small systems, which are 2.32% of the 11,820 small
systems regulated by the LT2ESWTR, will experience an impact of one
percent or greater of average annual revenues; further, 31 systems,
which are 0.26% of the systems regulated by this rule, will experience
an impact of three percent or greater of average annual revenues (see
Table VII-1).

Table VII-1.--Annualized Compliance Cost as a Percentage of Revenues for Small Entities ($2000)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Systems experiencing Systems experiencing
Average annual costs of % costs of % of
Number of small estimated their revenues their revenues
Entity by system size systems revenuses per ---------------------------------------------------
(Percent) system ($) Percent of Number of Percent of Number of
sustem systems systems systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
A B E F=A*E G H=A*G
---------------------------------------------------------------
Small Governments............................................. 5,910 50 2,434,200 2.4 140 0.3 15
Small Businesses.............................................. 4,846 41 2,391,978 2.4 115 0.3 13
Small Organizations........................................... 1,064 9 4,446,165 1.2 13 0.1 1
All Small Entities............................................ 11,820 100 2,597,966 2.3 274 0.3 31
Note: Detail may not add due to independent rounding. Data are based on the means of the highest modeled distributions using Information Collection Rule
occurrence data set. Costs are discounted at 3 percent, summed to present value, and annualized over 25 years. Source: Chapter 7 of the LT2ESWTR EA
(USEPA 2003a).

The LT2ESWTR contains provisions that will affect systems serving
fewer than 10,000 people that use surface water or GWUDI as a source.
In order to meet the LT2ESWTR requirements, approximately 1,382 to
2,127 small systems would need to make capital improvements. Impacts on
small entities are described in more detail in Chapters 6 and 7 of the
Economic Analysis for the LT2ESWTR (USEPA 2003a). Table VII-2 shows the
annual compliance costs of the LT2ESWTR on the small entities by system
size and type based on a three percent discount rate (other estimates
based on different data sets and discount rates produce lower costs).
EPA has determined that in each size category, fewer than 20% of
systems and fewer than 1000 systems will experience an impact of one
percent or greater of average annual revenues (USEPA 2003a).

[[Page 47760]]

Table VII-2.--Annual Compliance Costs for the Proposed LT2ESWTR by System Size and Type
[$Millions, 2000$]
----------------------------------------------------------------------------------------------------------------
System size (population served)
System type --------------------------------------------------------------- Total
<100 101-500 501-1,000 1,001-3,300 3,301-10,000
----------------------------------------------------------------------------------------------------------------
Public owned......................... $0.46 $0.88 $0.94 $2.62 $5.57 $10.37
Privately owned...................... 1.00 0.71 0.22 0.31 0.36 2.60
All systems.......................... 1.45 1.59 1.07 2.92 5.93 12.97
----------------------------------------------------------------------------------------------------------------
Note: Results are based on the mean of the Information Collection Rule Cryptosporidium occurrence distribution.
Costs are annualized at a three percent discount rate.
Source: Appendix D and Q of the LT2ESWTR EA (USEPA 2003a).

Although this proposed rule will not have a significant economic
impact on a substantial number of small entities, EPA nonetheless has
tried to reduce the impact of this rule on small entities. The LT2ESWTR
contains a number of provisions to minimize the impact of the rule on
systems generally, and on small systems in particular. The risk-
targeted approach of the LT2ESWTR will impose additional treatment
requirements only on the subset of systems with the highest
vulnerability to Cryptosporidium, as indicated by source water pathogen
levels. This approach will spare the majority of systems from the cost
of installing additional treatment. Also, development of the microbial
toolbox under the LT2ESWTR will provide both large and small systems
with broad flexibility in selecting cost-effective compliance options
to meet additional treatment requirements.
Small systems will monitor for E. coli as a screening analysis for
source waters with low levels of fecal contamination. Cryptosporidium
monitoring will only be required of small systems if they exceed the E.
coli trigger value. Because E. coli analysis is much cheaper than
Cryptosporidium analysis, the use of E. coli as a screen will
significantly reduce monitoring costs for the majority of small
systems. In order to allow EPA to review Cryptosporidium indicator
relationships in large system monitoring data, small systems will not
be required to initiate their monitoring until large system monitoring
has been completed. This will provide small systems with additional
time to become familiar with the rule and to prepare for monitoring and
other compliance activities.
Funding would be available from programs administered by EPA and
other Federal agencies to assist small public water systems (PWSs) in
complying with the LT2ESWTR. The Drinking Water State Revolving Fund
(DWSRF) assists PWSs with financing the costs of infrastructure needed
to achieve or maintain compliance with SDWA requirements. Through the
DWSRF, EPA awards capitalization grants to States, which in turn can
provide low-cost loans and other types of assistance to eligible PWSs.
Loans made under the program can have interest rates between 0 percent
and market rate and repayment terms of up to 20 years. States
prioritize funding based on projects that address the most serious
risks to human health and assist systems most in need. Congress
provided $1.275 billion for the DWSRF program in fiscal year 1997, and
has provided an additional $3.145 billion for the DWSRF program for
fiscal years 1998 through 2001.
The DWSRF places an emphasis on small and disadvantaged
communities. States must provide a minimum of 15% of the available
funds for loans to small communities. A State has the option of
providing up to 30% of the grant awarded to the State to furnish
additional assistance to State-defined disadvantaged communities. This
assistance can take the form of lower interest rates, principal
forgiveness, or negative interest rate loans. The State may also extend
repayment terms of loans for disadvantaged communities to up to 30
years. A State can set aside up to 2% of the grant to provide technical
assistance to systems serving communities with populations fewer than
10,000.
In addition to the DWSRF, money is available from the Department of
Agriculture's Rural Utility Service (RUS) and Housing and Urban
Development's Community Development Block Grant (CDBG) program. RUS
provides loans, guaranteed loans, and grants to improve, repair, or
construct water supply and distribution systems in rural areas and
towns of up to 10,000 people. In fiscal year 2002, RUS had over $1.5
billion of available funds for water and environmental programs. The
CDBG program includes direct grants to States, which in turn are
awarded to smaller communities, rural areas, and colon as in Arizona,
California, New Mexico, and Texas and direct grants to U.S. territories
and trusts. The CDBG budget for fiscal year 2002 totaled over $4.3
billion.
Although not required by the RFA to convene a Small Business
Advocacy Review (SBAR) Panel because EPA determined that this proposal
would not have a significant economic impact on a substantial number of
small entities, EPA did convene a panel to obtain advice and
recommendations from representatives of the small entities potentially
subject to this rule's requirements.
Before convening the SBAR Panel, EPA consulted with a group of 24
small entity stakeholders likely to be impacted by the LT2ESWTR and who
were asked to serve as Small Entity Representatives (SERs) after the
Panel was convened. The small entity stakeholders included small system
operators, local government representatives, and representatives of
small nonprofit organizations. The small entity stakeholders were
provided with background information on SDWA and potential alternatives
for the LT2ESWTR in preparation for teleconferences on January 28,
2000, February 25, 2000, and April 7, 2000. This information package
included data on preliminary unit costs for treatment enhancements
under consideration.
During these three conference calls, the information that had been
provided to the small entity stakeholders was discussed and EPA
responded to questions and recorded initial comments. Following the
three calls, the small entity stakeholders were asked to provide input
on the potential impacts of the rule from their perspective. Seven
small entity stakeholders provided written comments on these materials.
The SBAR Panel convened on April 25, 2000. The small entity
stakeholders comments were provided to the SBAR Panel when it convened.
After a teleconference between the SERs and the SBAR Panel on May 25,
2000, the SERs were invited to provide additional

[[Page 47761]]

comments on the information provided. Seven SERs provided additional
comments on the rule components.
The SBAR Panel's report, Final Report of the Small Business
Advocacy Review Panel on Stage 2 Disinfectants and Disinfection
Byproducts Rule (Stage 2 DBPR) and Long Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR) (USEPA 2000f), the SERs comments on the
LT2ESWTR, and the background information provided to the SBAR Panel and
the SERs are available for review in the docket for today's proposal
(http://www.epa.gov.edocket/).
In general, the SERs who were consulted on the LT2ESWTR were
concerned about the impact of these proposed rules on small water
systems, the ability of small systems to acquire the technical and
financial capability to implement requirements while maintaining
flexibility to tailor the requirements to their needs, and the
limitations of small systems. The SBAR Panel evaluated information and
small-entity comments on issues related to the impact of the LT2ESWTR.
The LT2ESWTR takes into consideration the recordkeeping and
reporting concerns identified by the SBAR Panel and the SERs. The SBAR
Panel recommended that EPA evaluate ways to minimize the recordkeeping
and reporting burdens under the rule by ensuring that the States have
appropriate capacity for rule implementation, and that EPA provide as
much monitoring flexibility as possible to small systems. EPA believes
that the continuity with the IESWTR and LT1ESWTR was maintained to the
extent possible to ease the transition to the LT2ESWTR, especially for
small systems. The LT2ESWTR builds on the protection afforded under the
IESWTR and LT1ESWTR, while minimizing the impact on small systems by
using a risk-targeted approach (i.e., source water monitoring) to
identify systems that are still at risk from Cryptosporidium exposure.
The SBAR Panel noted the concern of several SERs that flexibility
be provided in the compliance schedule of the rule. SERs commented on
the technical and financial limitations of some small systems, the
significant learning curve for operators with limited experience, and
the need to continue providing uninterrupted service as reasons why
additional compliance time may be needed for small systems. The SBAR
Panel encouraged EPA to keep these limitations in mind in developing
the proposed rule and provide as much compliance flexibility to small
systems as is allowable under SDWA.
EPA has concluded that the proposed schedule for the LT2ESWTR
provides sufficient time for small systems to achieve compliance. The
schedule for small system monitoring and compliance with additional
treatment requirements lags behind the schedule for large systems. The
basis for the lagging schedule for small systems is that it allows EPA
to confirm or refine the E. coli screening criteria that small systems
will use to reduce monitoring costs. However, the lagging schedule also
provides greater time for small systems to become knowledgeable about
the LT2ESWTR, including the new monitoring requirements, and to become
familiar with innovative technologies, like UV, that may be used by
some small systems to meet additional treatment requirements.
Some SERs emphasized that EPA needs to maintain an appropriate
balance between control of known microbial risks through adequate
disinfection and for the more uncertain risks that may be associated
with DBPs. The SBAR Panel did not foresee any potential conflict
between rules regulating control of microbial contaminants and those
regulating DBPs. EPA also believes that today's proposal and the
accompanying proposed Stage 2 DBPR achieve an appropriate balance
between microbial and DBP risks. The profiling and benchmarking
requirements described in section IV.D of this preamble will ensure
that systems maintain protection against pathogens as they make
treatment changes to control the formation of DBPs.
The SBAR Panel considered a wide range of options and regulatory
alternatives for providing small businesses with flexibility in
complying with the LT2ESWTR. The SBAR Panel was concerned with the
option of an across-the-board additional Cryptosporidium inactivation
requirement because of the potential high cost to small systems and the
uncertainty regarding the extent to which implementation of the
LT1ESWTR will adequately address Cryptosporidium contamination at small
systems. The SBAR Panel noted that, at the time, the Stage 2 M-DBP
Federal Advisory Committee was exploring a targeted approach to
Cryptosporidium control based on limited monitoring and system
assessment, which would identify a subset of vulnerable systems to
provide additional treatment in the range of 0.5-to 2.5-log reduction.
Further, this approach would allow E. coli monitoring in lieu of
Cryptosporidium monitoring as a screening device for small systems. The
SBAR Panel was also encouraged by recent developments suggesting that
UV is a viable, cost-effective means of fulfilling any additional
inactivation requirements.
The SBAR Panel recommended that, in developing any additional
inactivation requirements based on a targeted approach, EPA carefully
consider the potential impacts on small systems and attempt to
structure the regulatory requirements in a way that would minimize
burden on this group. The SBAR Panel supported E. coli as an indicator
parameter if additional monitoring is required. The SBAR Panel further
recommended that, among the options EPA analyzes, the Agency also
evaluate the option of not imposing any additional Cryptosporidium
control requirements on small systems at this time, as it considers
various options to address microbial concerns. Under this option, EPA
would evaluate the effects of LT1ESWTR, once implemented, and then
consider whether to impose additional requirements during its next 6-
year review of the standard, as required by SDWA.
EPA considered these recommendations and has concluded that
available information on the health risk associated with
Cryptosporidium in drinking water warrant moving forward with today's
proposal to address higher risk systems. In developing the proposed
LT2ESWTR, EPA has implemented the Advisory Committee's recommendations
to minimize burden on small systems. Specifically, the risk-targeted
treatment requirements will substantially reduce overall costs for
small systems in comparison to requiring additional treatment by all
systems, and the use of E. coli screening will allow most small systems
to avoid the cost of Cryptosporidium monitoring. Consequently, the
Agency has concluded that today's proposal achieves an appropriate
balance between public health protection and limiting the economic
burden imposed on small entities.
We continue to be interested in the potential impacts of the
proposed rule on small entities and welcome comments on issues related
to such impacts.

D. Unfunded Mandates Reform Act

1. Summary of UMRA Requirements
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public
Law 104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and Tribal
governments and the private sector. Under section 202 of UMRA,

[[Page 47762]]

EPA generally must prepare a written statement, including a cost-
benefit analysis, for proposed and final rules with ``Federal
mandates'' that may result in expenditures to State, local and Tribal
governments, in the aggregate, or to the private sector, of $100
million or more in any one year. Before promulgating an EPA rule for
which a written statement is needed, section 205 of the UMRA generally
requires EPA to identify and consider a reasonable number of regulatory
alternatives and adopt the least costly, most cost-effective or least
burdensome alternative that achieves the objectives of the rule. The
provisions of section 205 do not apply when they are inconsistent with
applicable law. Moreover, section 205 allows EPA to adopt an
alternative other than the least costly, most cost-effective or least
burdensome alternative if the Administrator publishes with the final
rule an explanation why that alternative was not adopted.
Before EPA establishes any regulatory requirements that may
significantly or uniquely affect small governments, including Tribal
governments, it must have developed under section 203 of the UMRA a
small government agency plan. The plan must provide for notifying
potentially affected small governments, enabling officials of affected
small governments to have meaningful and timely input in the
development of EPA regulatory proposals with significant Federal
intergovernmental mandates, and informing, educating, and advising
small governments on compliance with the regulatory requirements.
2. Written Statement for Rules With Federal Mandates of $100 Million or
More
EPA has determined that this rule contains a Federal mandate that
may result in expenditures of $100 million or more for State, local,
and Tribal governments, in the aggregate, or the private sector in any
one year. Accordingly, EPA has prepared under section 202 of the UMRA a
written statement which is summarized in this section. Table VII-3
illustrates the annualized public and private costs for the LT2ESWTR.

Table VII-3.--Public and Private Costs of the Proposed LT2ESWTR
----------------------------------------------------------------------------------------------------------------
Range of annualized costs
(Million $, 2000$)
-------------------------------- Percent of
3% Discount 7% Discount total cost
rate rate
----------------------------------------------------------------------------------------------------------------
PWS Costs....................................................... $45.7-69.0 $50.2-75.2 62.2-62.4
State Costs..................................................... 0.9-1.0 1.2-1.2 1.3-0.9
Tribal Costs.................................................... 0.1-0.2 0.1-0.2 0.1-0.1
-----------------
Total Public Costs.......................................... 46.7-70.1 51.5-76.6 63.6-63.4
Total Private Costs......................................... 26.8-40.4 29.4-44.1 36.4-36.6
-----------------
Total Costs............................................. 73.5-110.5 80.9-120.7 100.0-100.0
----------------------------------------------------------------------------------------------------------------
Note: The ranges represent the ICRSSL (lowest) and Information Collection Rule (highest) modeled Cryptosporidium
occurrence distributions. Detail may not add due to independent rounding.
Source: The LT2ESWTR Economic Analysis (USEPA 2003a).

A more detailed description of this analysis is presented in
Economic Analysis for the LT2ESWTR (USEPA 2003a).
a. Authorizing legislation. As noted in section II, today's
proposed rule is promulgated pursuant to section 1412 (b)(1)(A) of the
Safe Drinking Water Act (SDWA), as amended in 1996, which directs EPA
to promulgate a national primary drinking water regulation for a
contaminant if EPA determines that the contaminant may have an adverse
effect on the health of persons, occurs in public water systems with a
frequency and at levels of public health concern, and regulation
presents a meaningful opportunity for health risk reduction.
b. Cost-benefit analysis. Section VI of this preamble discusses the
cost and benefits associated with the LT2ESWTR. Details are presented
in the Economic Analysis for the LT2ESTWR (USEPA 2003a). For the
LT2ESWTR proposal, EPA quantified costs and benefits for four
regulatory alternatives. The four alternatives are described in section
VI. Table VII-4 summarizes the range of annual costs and benefits for
each alternative.

Table VII-4.--Annual Benefits and Costs of Rule Alternatives
[$Million]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Enhanced COI Traditional Enahnced COI Tradition COI
range of COI range of range of range of Range of Range of
Regulatory Alternative annualized annualized annualized annualized annualized annualized
benefits (3%) benefits (3%) benefits (7%) benefits (7%) costs (3%) costs (7%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Alternative A1.......................................... $457-1,492 $305-989 $389-1,260 $260-845 $361 $388
Alternative A2.......................................... 397-1,461 268-977 338-1,243 229-834 100-134 108-145
Alternative A3.......................................... 374-1,445 253-967 318-1,230 216-826 73-111 81-121
(Preferred Alternative).................................
Alternative A4.......................................... 328-1,349 225-907 279-1,148 192-775 37-59 41-65
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: The LT2ESWTR Economic Analysis (USEPA 2003a).

c. Estimates of future compliance costs and disproportionate
budgetary effects. To meet the UMRA requirement in section 202, EPA
analyzed future compliance costs and possible disproportionate
budgetary effects. The Agency believes that the cost estimates,
indicated earlier and discussed in more detail in section VI of this
preamble,

[[Page 47763]]

accurately characterize future compliance costs of the proposed rule.
In analyzing disproportionate impacts, the Agency considered the
impact on (1) different regions of the United States, (2) State, local,
and Tribal governments, (3) urban, rural and other types of
communities, and (4) any segment of the private sector. This analysis
is presented in section 7 of Economic Analysis for the LT2ESWTR (USEPA
2003a).
EPA has concluded that the LT2ESWTR will not cause a
disproportionate budgetary effect. This rule imposes the same
requirements on systems nationally and does not disproportionately
affect any segment. This rule will treat similarly situated systems (in
terms of size, water quality, available data, installed technology, and
presence of uncovered finished storage facilities) in similar
(proportionate) ways, without regard to geographic location, type of
community, or segment of industry. The LT2ESWTR is a rule where
requirements are proportionate to risk. Although some groups may have
differing budgetary effects as a result of LT2ESWTR, those costs are
proportional to the need for greater information (monitoring) and risk
posed (degree of treatment required). The variation in cost between
large and small systems is due to economies of scale (a larger system
can distribute cost across more customers). Regions will have varying
impacts due to the number of affected systems.
d. Macro-economic effects. Under UMRA section 202, EPA is required
to estimate the potential macro-economic effects of the regulation.
These types of effects include those on productivity, economic growth,
full employment, creation of productive jobs, and international
competitiveness. Macro-economic effects tend to be measurable in
nationwide econometric models only if the economic impact of the
regulation reaches 0.25 percent to 0.5 percent of Gross Domestic
Product (GDP). In 2000, real GDP was $9,224 billion, so a rule would
have to cost at least $23 billion to have a measurable effect. A
regulation with a smaller aggregate effect is unlikely to have any
measurable impact unless it is highly focused on a particular
geographic region or economic sector.
The macro-economic effects on the national economy from the
LT2ESWTR should not have a measurable effect because the total annual
costs for the proposed option range from $73 million to $111 million
based on median Cryptosporidium occurrence distributions from the
ICRSSL and Information Collection Rule data sets and a discount rate of
3 percent ($81 to $121 million at a 7 percent discount rate). These
annualized figures will remain constant over the 25-year implementation
period that was evaluated, while GDP will probably continue to rise.
Thus, LT2ESWTR costs measures as a percentage of the national GDP will
only decline over time. Costs will not be highly focused on a
particular geographic region or sector.
e. Summary of EPA consultation with State, local, and Tribal
governments and their concerns. Consistent with the intergovernmental
consultation provisions of section 204 of UMRA, EPA has already
initiated consultations with the governmental entities affected by this
rule. A variety of stakeholders, including small governments, were
provided the opportunity for timely and meaningful participation in the
regulatory development process. EPA used these opportunities to notify
potentially affected governments of regulatory requirements being
considered.
The Stage 2 M-DBP Federal Advisory Committee included
representatives from State government (Association of State Drinking
Water Administrators, Environmental Commissioners of States), local
government (National League of Cities), and Tribes (All Indian Pueblo
Council (AIPC)). Government and Tribal representatives on the Advisory
Committee were generally concerned with ensuring that drinking water
regulations are adequately protective of public health and that any
additional public health expenditures due to new regulations achieve
significant risk reduction. The proposed LT2ESWTR reflects the
consensus recommendations of the Advisory Committee, as stated in the
Agreement in Principle (65 FR 83015, December 29, 2000). Consequently,
EPA believes that the risk-targeted approach for additional
Cryptosporidium treatment requirements and other provisions in today's
proposal satisfies the concerns of the government and Tribal
representatives on the Advisory Committee.
As described in section VII.C of this preamble, the Agency convened
a Small Business Advocacy Review (SBAR) Panel in accordance with the
Regulatory Flexibility Act (RFA) as amended by the Small Business
Regulatory Enforcement Fairness Act to address the concerns of small
entities, including small local governments specifically. Small entity
representatives (SERs) to the SBAR panel, including representatives of
small local governments, were concerned about the cost of the rule, the
technical capability of small systems to implement requirements, and
flexibility in regulatory requirements and in the compliance schedule.
SERs also emphasized that EPA needs to balance the control of known
microbial risks with the risks associated with DBPs.
Today's proposal is responsive to these concerns, as stated in
section VII.C. The LT2ESWTR will impose costs for additional treatment
on only the fraction of systems identified through monitoring as being
at higher risk, and overall monitoring costs for small systems will be
greatly reduced through use of the E. coli screening to waive small
systems from Cryptosporidium monitoring. The microbial toolbox of
treatment options will provide significant flexibility to systems to
identify cost-effective solutions for meeting additional
Cryptosporidium treatment requirements. The compliance schedule for
small systems is delayed in relation to large systems, which will allow
small systems additional time to become knowledgeable about and prepare
to implement the LT2ESWTR. The intent of the proposed disinfection
profiling provisions is to ensure that when systems make treatment
changes to control DBP formation, they maintain protection against
pathogens.
EPA held a meeting on the LT2ESWTR in February 2001 with
representatives of State and local governments. Representatives of the
following organizations attended: Association of State Drinking Water
Administrators (ASDWA), the National Governors' Association (NGA), the
National Conference of State Legislatures (NCSL), the International
City/County Management Association (ICMA), the National League of
Cities (NLC), the County Executives of America, and health departments.
Representatives asked questions regarding how Cryptosporidium gets into
the water, whether EPA would add laboratory approval for
Cryptosporidium to State certification programs, the effectiveness of
ozone and UV, and the development of ambient water quality criteria for
Cryptosporidium.
EPA has largely addressed these questions in this preamble. Section
II characterizes sources of Cryptosporidium. As described in section
IV.K, EPA is currently carrying out a laboratory approval program for
Cryptosporidium analyses but expects that this will be included in
State laboratory certification programs in the future. In section
IV.C., EPA describes the effectiveness of ozone and UV for
Cryptosporidium inactivation and provides criteria for how these
technologies may be used to comply with the treatment requirements in

[[Page 47764]]

today's proposal. The Agency is currently exploring the development of
ambient water quality criteria for Cryptosporidium, but such criteria
are not available at this time and are not included in today's
proposal.
In addition to the Tribal representative on the Advisory Committee,
EPA conducted outreach and consultation with Tribal representatives on
a number of occasions regarding the LT2ESWTR. EPA presented the
LT2ESWTR at the following forums: the 16th Annual Consumer Conference
of the National Indian Health Board, which included over 900
representatives of Tribes across the nation; the annual conference of
the National Tribal Environmental Council, at which over 100 Tribes
were represented; and the 1999 EPA/Inter-Tribal Council of Arizona,
which included representatives from 15 Tribes. EPA also sent the
presentation materials used in the first two meetings and meeting
summaries to over 500 Tribes and Tribal organizations.
Fact sheets describing the requirements of the LT2ESWTR and
requesting Tribal input were distributed at an annual EPA Tribal
meeting in San Francisco and at a Native American Water Works
Association meeting in Scottsdale, Arizona. EPA also worked through its
Regional Indian Coordinators and the National Tribal Operations
Committee to raise awareness of the development of the proposed rule.
EPA mailed all Federal Tribes LT2ESWTR fact sheets in November 2000.
The Tribal representative to the Advisory Committee also presented the
Stage 2 Agreement in Principle prior to signature in at least one
political forum for various Tribes not affiliated with AIPC.
EPA held a teleconference in January 2002 with 12 Tribal
representatives and four Regional Tribal Program Coordinators. Prior to
the teleconference, EPA sent invitations to all Federal Tribes, along
with a fact sheet explaining the LT2ESWTR.
Through this consultation, Tribal representatives expressed concern
about implementing new regulations without additional funding sources.
However, they also stated that the LT2ESWTR would have a benefit, and
asserted that people served by small systems should receive equivalent
public health protection. Questions were asked regarding the impact of
the rule (e.g., number of Tribal surface water systems) and the date
for finalizing the rule. The Tribal representative to the M-DBP
Advisory Committee advocated that risk mitigation plans for uncovered
finished water storage facilities should account for cultural uses by
Tribes.
In response to the concerns expressed by Tribal representatives,
EPA noted that the LT2ESWTR proposal is designed to minimize costs by
targeting higher risk systems, and includes other provisions, described
earlier, to reduce burden. Moreover, the projected benefits of the rule
substantially exceed costs. EPA also explained that capital projects
related to the rule would be eligible for Federal funding sources, such
as the Drinking Water State Revolving Fund, due to the health risks
associated with Cryptosporidium. The LT2ESWTR Economic Analysis (USEPA
2003a) provides an analysis of the impact of the LT2ESWTR on Tribes.
EPA has identified 67 Tribal water systems that would be subject to the
LT2ESWTR.
In addition to these direct consultations with State, local, and
Tribal governments, EPA posted a pre-proposal draft of the LT2ESWTR
proposal on an EPA Internet site (http://www.epa.gov/safewater/) in
November 2001. EPA received comments on this pre-proposal draft from
ASDWA and six States, several public water systems owned by local
governments, as well as private water systems, laboratories, and other
stakeholders. Among the concerns raised by commenters representing
State and local governments were the following: early implementation of
monitoring by large systems; flexibility for States in awarding
treatment credits to different Cryptosporidium control technologies;
and the added burden of the rule on systems and States.
EPA has addressed these concerns in developing the LT2ESWTR
proposal. As described in section IV.J, EPA is planning to directly
implement the large system monitoring requirements that occur during
the first 2.5 years after promulgation. The planned approach is similar
to that used for the UCMR, including an electronic data reporting
system for storing monitoring results and tracking compliance. With
this approach, States will be able to access data reported by their
systems, thereby allowing States to exercise oversight of their systems
during early implementation if they chose. However, EPA will take
primary responsibility for providing technical assistance to systems
and assessing compliance with monitoring requirements.
In regard to treatment credit for Cryptosporidium control
technologies, the Agency has made substantial efforts to ensure that
the criteria in today's proposal are based on the best available data.
EPA has worked in partnership with industry and researchers to gather
information, and proposed criteria for several microbial toolbox
options reflect comments by the Science Advisory Board. In addition,
today's proposal gives flexibility to States by allowing them to award
different levels of Cryptosporidium treatment credit to their systems
based on site-specific demonstrations.
With respect to the burden the LT2ESWTR would place on water
systems and States, EPA has, as described previously in this preamble,
attempted to minimize overall costs under the proposed LT2ESWTR. This
is achieved through risk-targeting of additional treatment
requirements, allowing most small systems to avoid Cryptosporidium
monitoring costs through E. coli screening, and facilitating the use of
lower cost treatment technologies like UV.
In summary, EPA has concluded that the proposed option for the
LT2ESWTR is needed to provide a significant public health benefit by
reducing exposure to Cryptosporidium. While many public water systems
achieve adequate control of Cryptosporidium, additional treatment
should be required for filtered systems with elevated source water
pathogen levels and for unfiltered systems. The availability of
improved analytical methods allows additional treatment requirements to
be targeted to higher risk systems, and the development of technologies
like UV makes it feasible for systems to provide additional treatment.
The monetized benefits of today's proposal significantly exceed total
costs, and EPA believes there will be substantial unquantified benefits
as well.
f. Regulatory alternatives considered. As required under section
205 of UMRA, EPA considered several regulatory alternatives to address
systems at risk for contamination by microbial pathogens, specifically
including Cryptosporidium. A detailed discussion of these alternatives
can be found in section VI of the preamble and also in the Economic
Analysis for the LT2ESWTR (USEPA 2003a).
g. Selection of the least costly, most cost-effective, or least
burdensome alternative that achieves the objectives of the rule. Among
the regulatory alternatives considered for the LT2ESWTR, as described
in section VI, the Agency believes the proposed alternative is the most
cost-effective that achieves the objectives of the rule. The objective
of the LT2ESWTR is to reduce risk from Cryptosporidium and other
pathogens in systems where current regulations do not provide
sufficient protection.
The Agency evaluated a less costly and less burdensome alternative.

[[Page 47765]]

However, this alternative would provide no benefit to several thousand
consumers who, under the proposed alternative, would receive benefits
that most likely exceed their costs, based on Agency estimates. This is
illustrated in the LT2ESWTR Economic Analysis (USEPA 2003a). By failing
to reduce risk for consumers where additional treatment requirements
would be cost-effective, the less costly alternative does not appear to
achieve the objectives of the LT2ESWTR.
The other alternatives considered by the Agency achieve the
objectives of the rule, but are more costly, more burdensome, and
potentially less cost-effective. The proposed alternative targets
additional treatment requirements to systems with the highest
vulnerability to Cryptosporidium, and maximizes net benefits under a
broad range of conditions (USEPA 2003a). Consequently, the Agency has
found the proposed alternative to be the most cost-effective among
those that achieve the objectives of the rule.
3. Impacts on Small Governments
EPA has determined that this rule contains no regulatory
requirements that might significantly or uniquely affect small
governments. Thus, today's rule is not subject to the requirements of
section 203 of UMRA. As described in section VII.C, EPA has certified
that this proposed rule will not have a significant economic impact on
a substantial number of small entities. Estimated annual expenditures
by small systems for the LT2ESWTR range from $7.9 to $13.0 million at a
3% discount rate and $8.0 to $13.0 million at a 7% discount rate. While
the treatment requirements of the LT2ESWTR apply uniformly to both
small and large public water systems, large systems bear a majority of
the total costs of compliance with the rule. This is due to the fact
that large systems treat a majority of the drinking water that
originates from surface water sources.

E. Executive Order 13132: Federalism

Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
``Policies that have federalism implications'' is defined in the
Executive Order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.''
Under Executive Order 13132, EPA may not issue a regulation that
has federalism implications, that imposes substantial direct compliance
costs, and that is not required by statute, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by State and local governments, or EPA consults with
State and local officials early in the process of developing the
proposed regulation.
EPA has concluded that this proposed rule may have federalism
implications, because it may impose substantial direct compliance costs
on State or local governments, and the Federal government will not
provide the funds necessary to pay those costs. The proposed rule may
result in expenditures by State, local, and Tribal governments, in the
aggregate of $100 million or more in any one year. Costs are estimated
to range from $73 to $111 million at a 3 percent discount rate and $81
to $121 million using a 7 percent discount rates based on the median
distribution modeled from ICRSSL and Information Collection Rule
Cryptosporidium occurrence data sets. Accordingly, EPA provides the
following federalism summary impact statement as required by section
6(b) of Executive Order 13132.
EPA consulted with representatives of State and local officials
early in the process of developing the proposed regulation to permit
them to have meaningful and timely input into its development. Section
VII.D.2.e describes EPA's consultation with representatives of State
and local officials. This consultation included State and local
government representatives on the Stage 2 M-DBP Federal Advisory
Committee, the representatives from small local governments to the SBAR
panel, a meeting with representatives from ASDWA, NGA, NCSL, ICMA, NLC,
the County Executives of America, and health departments, consultation
with Tribal governments at four meetings, and comments from State and
local governments on a pre-proposal draft of the LT2ESWTR.
Representatives of State and local officials were generally
concerned with ensuring that drinking water regulations are adequately
protective of public health and that any additional regulations achieve
significant health benefits in return for required expenditures. They
were specifically concerned with the burden of the proposed rule, both
in cost and technical complexity, giving flexibility to systems and
States, balancing the control of microbial risks and DBP risks, funding
for implementing new regulations, equal protection for small systems,
and early implementation of monitoring by large systems.
EPA has concluded that the proposed LT2ESWTR is needed to reduce
the public health risk associated with Cryptosporidium in drinking
water. Estimated benefits for the rule are significantly higher than
costs. Further, as described in this section and in section VII.D.2.e,
the Agency believes that today's proposal addresses many of the
concerns expressed by representatives of government officials.
Under the proposed LT2ESWTR, expenditures for additional treatment
are targeted to the fraction of systems with the highest vulnerability
to Cryptosporidium, thereby minimizing burden for the majority of
systems that will not be required to provide additional treatment. The
microbial toolbox of compliance options will provide flexibility to
systems in meeting additional treatment requirements, and States have
the flexibility to award treatment credits based on site-specific
demonstrations. Disinfection profiling provisions are intended to
ensure that systems do not reduce microbial protection as they take
steps to reduce exposures to DBPs.
The LT2ESWTR achieves equal public health protection for small
systems. However, the use of E. coli monitoring by small systems as a
screening analysis to determine the need for Cryptosporidium monitoring
will reduce monitoring costs for most small systems. Capital projects
related to the rule would be eligible for funding from the Drinking
Water State Revolving Fund, which includes specific funding for small
communities. EPA is planning to support the initial monitoring by large
systems that takes place within the first 2.5 years after promulgation.
This will substantially reduce the burden on States associated with
early implementation of monitoring requirements.
In the spirit of Executive Order 13132, and consistent with EPA
policy to promote communications between EPA and State and local
governments, EPA specifically solicits comment on this proposed rule
from State and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments'' (65 FR 67249, November 9, 2000),
requires EPA

[[Page 47766]]

to develop ``an accountable process to ensure meaningful and timely
input by Tribal officials in the development of regulatory policies
that have Tribal implications.'' ``Policies that have Tribal
implications'' is defined in the Executive Order to include regulations
that have ``substantial direct effects on one or more Indian tribes, on
the relationship between the Federal government and the Indian tribes,
or on the distribution of power and responsibilities between the
Federal government and Indian tribes.''
Under Executive Order 13175, EPA may not issue a regulation that
has Tribal implications, that imposes substantial direct compliance
costs, and that is not required by statute, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by Tribal governments, or EPA consults with Tribal
officials early in the process of developing the proposed regulation
and develops a Tribal summary impact statement.
EPA has concluded that this proposed rule may have Tribal
implications, because it may impose substantial direct compliance costs
on Tribal governments, and the Federal government will not provide the
funds necessary to pay those costs. EPA has identified 67 Tribal water
systems serving a total population of 78,956 that may be subject to the
LT2ESWTR. They will bear an estimated total annualized cost of $135,974
at a 3 percent discount rate ($138,910 at 7 percent) to implement this
rule as proposed. Estimated mean annualized cost per system ranges from
$792 to $23,979 at a 3 percent discount rate ($844 to $26,194 at 7
percent) depending on system size (see section 7 of the LT2ESWTR
Economic Analysis (USEPA 2003a) for details). Accordingly, EPA provides
the following Tribal summary impact statement as required by section
5(b) of Executive Order 13175.
EPA consulted with representatives of Tribal officials early in the
process of developing this regulation to permit them to have meaningful
and timely input into its development. Section VII.D.2.e describes
EPA's outreach and consultation with Tribes, which included
presentations on the LT2ESWTR at four Tribal conferences and meetings,
mailing fact sheets and presentation materials regarding the proposal
to Tribes on several occasions, and a teleconference with
representatives of Tribal officials to comment on the proposed rule.
As discussed in section VII.D.2.e, Tribal representatives stated
that protection of public health is important regardless of the number
of people a system is serving, and they recognized that the LT2ESWTR
would provide a public health benefit. However, Tribal representatives
were concerned about the availability of funding to implement the
regulation and asked about the projected impact on Tribes (e.g., number
of Tribal surface water systems that would be affected). Also, the
Tribal representative to the Federal Advisory Committee was concerned
that risk mitigation plans for uncovered finished water storage
facilities account for cultural uses by Tribes.
EPA has concluded that the proposed LT2ESWTR is needed to reduce
the risk associated with Cryptosporidium in public water systems using
surface water sources. Projected benefits for today's proposal are
substantially greater than costs. Moreover, as described in this
section and in section VII.D.2.e, today's proposal addresses many of
the concerns stated by Tribal representatives.
The LT2ESWTR will provide equivalent public health protection to
all system sizes, including Tribal systems. By targeting additional
treatment requirements to higher risk systems, the LT2ESWTR will
minimize overall burden in comparison with requiring additional
treatment by all systems. In addition, the provision in the proposal
allowing E. coli screening to determine if Cryptosporidium monitoring
is necessary will reduce monitoring costs for many small Tribal
systems. (EPA notes that 66 of the 67 Tribal systems identified by the
Agency as subject to the LT2ESWTR are small systems.) Due to the health
risks associated with Cryptosporidium, capital expenditures needed for
compliance with the rule will be eligible for Federal funding sources,
specifically the Drinking Water State Revolving Fund. EPA is developing
guidance that will address consideration of Tribal cultural uses of
uncovered finished water storage facilities.
In the spirit of Executive Order 13175, and consistent with EPA
policy to promote communications between EPA and Tribal governments,
EPA specifically solicits additional comment on this proposed rule from
Tribal officials.

G. Executive Order 13045: Protection of Children from Environmental
Health and Safety Risks

Executive Order 13045: ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies
to any rule that: (1) Is determined to be ``economically significant''
as defined under Executive Order 12866, and (2) concerns an
environmental health or safety risk that EPA has reason to believe may
have a disproportionate effect on children. If the regulatory action
meets both criteria, the Agency must evaluate the environmental health
or safety effects of the planned rule on children and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the Agency.
This proposed rule is subject to the Executive Order because it is
an economically significant regulatory action as defined in Executive
Order 12866, and we believe that the environmental health or safety
risk addressed by this action may have a disproportionate effect on
children. Accordingly, we have evaluated the environmental health or
safety effects of Cryptosporidium on children. The results of this
evaluation are contained in Cryptosporidium: Risk for Infants and
Children (USEPA 2001d) and described in this section of this preamble.
Further, while available information is not adequate to conduct a
quantitative risk assessment specifically on children, EPA has assessed
the risk associated with Cryptosporidium in drinking water for the
general population, including children. This assessment is described in
the Economic Analysis for the LT2ESWTR (USEPA 2003a) and is summarized
in section VI of this preamble. Copies of these documents and
supporting information are available in the public docket for today's
proposal.
Cryptosporidiosis in children is similar to adult disease (USEPA
2001d). Diarrhea is the most common symptom. Other common symptoms in
otherwise healthy (i.e., immunocompetent) children include anorexia,
vomiting, abdominal pain, fever, dehydration and weight loss.
The risk of illness and death due to cryptosporidiosis depends on
several factors, including age, nutrition, exposure, genetic
variability, disease and the immune status of the individual. Mortality
resulting from diarrhea generally occurs at a greater rate among the
very young and elderly (Gerba et al., 1996). During the 1993 Milwaukee
drinking water outbreak, associated mortalities in children were
reported. Also, children with laboratory-confirmed cryptosporidiosis
were more likely to have an underlying disease that altered their
immune status (Cicirello et al., 1997). In that study, the observed
association between increasing age of children and increased numbers of
laboratory-confirmed cryptosporidiosis suggested to the authors that
the data

[[Page 47767]]

are consistent with increased tap water consumption of older children.
However, due to data limitations, this observation could not be
adequately analyzed. Asymptomatic infection, especially in
underdeveloped communities, can have a substantial effect on childhood
growth (Bern et al., 2002).
Cryptosporidiosis appears to be more prevalent in populations, such
as children, that may not have established immunity against the disease
and may be in greater contact with environmentally contaminated
surfaces (DuPont et al., 1995). In the United States, children aged one
to four years are more likely than adults to have the disease. The most
recent reported data on cryptosporidiosis shows the occurrence rate
(for the year 1999) is higher in children ages one to four (3.03
incidence rate per 100,000) than in any adult age group (CDC, 2001).
Evidence from blood sera antibodies collected from children during the
1993 Milwaukee outbreak suggest that children had greater levels of
Cryptosporidium infection than predicted for the general community
(based on the random-digit dialing telephone survey method) (McDonald
et al., 2001).
Data indicate a lower incidence of cryptosporidiosis infection
during the first year of life. This is attributed to breast-fed infants
consuming less tap water and, hence, having less exposure to
Cryptosporidium, as well as the possibility that mothers confer short
term immunity to their children. For example, in a survey of over
30,000 stool sample analyses from different patients in the United
Kingdom, the one to five year age group suffered a much higher
infection rate than individuals less than one year of age. For children
under one year of age, those older than six months of age showed a
higher rate of infection than individuals aged less than six months
(Casemore, 1990). Similarly, in the U.S., of 2,566 reported
Cryptosporidium illnesses in 1999, 525 occurred in ages one to four
(incidence rate of 3.03 per 100,000) compared with 58 cases in infants
under one year (incidence rate of 1.42 per 100,000) (CDC, 2001).
An infected child may spread the disease to other children or
family members (Heijbel et al., 1987, Osewe et al., 1996). Millard et
al. (1994) documented greater household secondary transmission of
cryptosporidiosis from children than from adults to household and other
close contacts. Children continued to shed oocysts for more than two
weeks (mean 16.5 days) after diarrhea cessation (Tangerman et al.,
1991).
While Cryptosporidium may have a disproportionate effect on
children, available data are not adequate to distinctly assess the
health risk for children resulting from Cryptosporidium-contaminated
drinking water. In assessing risk to children when evaluating
regulatory alternatives for the LT2ESWTR, EPA assumed the same risk for
children as for the population as a whole.
Section VI of this preamble presents the regulatory alternatives
that EPA evaluated for the proposed LT2ESWTR. Among the four
alternatives the Agency considered, three involved a risk-targeting
approach in which additional Cryptosporidium treatment requirements are
based on source water monitoring results. A fourth alternative involved
additional treatment requirements for all systems.
The alternative requiring additional treatment by all systems was
not selected because of concerns about feasibility and because it
imposed costs but provided few benefits to systems with high quality
source water (i.e., relatively low Cryptosporidium risk). The three
risk-targeting alternatives were evaluated based on several factors,
including costs, benefits, net benefits, feasibility of implementation,
and other specific impacts (e.g., impacts on small systems or sensitive
subpopulations).
The proposed alternative was recommended by the M-DBP Federal
Advisory Committee and selected by EPA as the Preferred Regulatory
Alternative because it was deemed feasible and provides significant
public health benefits in terms of avoided illnesses and deaths. EPA's
analysis of benefits and costs indicates that the proposed alternative
ranks highly among those evaluated with respect to maximizing net
benefits, as shown in the LT2ESWTR Economic Analysis (USEPA 2003a).
This document is available in the docket for this action.
The result of the LT2ESWTR will be a reduction in the risk of
illness for the entire population, including children. Because
available evidence indicates that children may be more vulnerable to
cryptosporidiosis than the rest of the population, the LT2ESWTR may,
therefore, result in greater risk reduction for children than for the
general population.
The public is invited to submit or identify peer-reviewed studies
and data, of which EPA may not be aware, that assessed results of early
life exposure to Cryptosporidium.

H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use

This rule is not a ``significant energy action'' as defined in
Executive Order 13211, ``Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 28355
(May 22, 2001)) because it is not likely to have a significant adverse
effect on the supply, distribution, or use of energy. This
determination is based on the following analysis.
The first consideration is whether the LT2ESWTR would adversely
affect the supply of energy. The LT2ESWTR does not regulate power
generation, either directly or indirectly. The public and private
utilities that the LT2ESWTR regulates do not, as a rule, generate
power. Further, the cost increases borne by customers of water
utilities as a result of the LT2ESWTR are a low percentage of the total
cost of water, except for a very few small systems that might install
advanced technologies and then need to spread that cost over a narrow
customer base. Therefore, the customers that are power generation
utilities are unlikely to face any significant effects as a result of
the LT2ESWTR. In sum, the LT2ESWTR does not regulate the supply of
energy, does not generally regulate the utilities that supply energy,
and is unlikely to affect significantly the customer base of energy
suppliers. Thus, the LT2ESWTR would not translate into adverse effects
on the supply of energy.
The second consideration is whether the LT2ESWTR would adversely
affect the distribution of energy. The LT2ESWTR does not regulate any
aspect of energy distribution. The utilities that are regulated by the
LT2ESWTR already have electrical service. As derived later in this
section, the proposed rule is projected to increase peak electricity
demand at water utilities by only 0.02 percent. Therefore, EPA
estimates that the existing connections are adequate and that the
LT2ESWTR has no discernable adverse effect on energy distribution.
The third consideration is whether the LT2ESWTR would adversely
affect the use of energy. Because some drinking water utilities are
expected to add treatment technologies that use electrical power, this
potential impact is evaluated in more detail. The analyses that
underlay the estimation of costs for the LT2ESWTR are national in scope
and do not identify specific plants or utilities that may install
treatment in response to the rule. As a result, no analysis of the
effect on specific energy suppliers is possible with the available

[[Page 47768]]

data. The approach used to estimate the impact of energy use,
therefore, focuses on national-level impacts. The analysis estimates
the additional energy use due to the LT2ESWTR, and compares that to the
national levels of power generation in terms of average and peak loads.
The first step in the analysis is to estimate the energy used by
the technologies expected to be installed as a result of the LT2ESWTR.
Energy use is not directly stated in Technologies and Costs for Control
of Microbial Contaminants and Disinfection By-Products (USEPA 2003c),
but the annual cost of energy for each technology addition or upgrade
necessitated by the LT2ESWTR is provided. An estimate of plant-level
energy use is derived by dividing the total energy cost per plant for a
range of flows by an average national cost of electricity of $0.076/kWh
(USDOE EIA, 2002). These calculations are shown in detail in Chapter 7
of the Economic Analysis for the LT2ESWTR (USEPA 2003a). The energy use
per plant for each flow range and technology is then multiplied by the
number of plants predicted to install each technology in a given flow
range. The energy requirements for each flow range are then added to
produce a national total. No electricity use is subtracted to account
for the technologies that may be replaced by new technologies,
resulting in a conservative estimate of the increase in energy use.
Results of the analysis are shown in Table VII-5 for each of the
modeled Cryptosporidium occurrence distributions. The results range
from an incremental national annual energy usage of 0.12 million
megawatt-hours (mW) for the modeled Information Collection Rule
occurrence distribution to 0.07 million mW for the modeled ICRSSL
occurrence distribution.

Table VII-5.--Total Increased Annual National Energy Usage Attributable to the LT2ESWTR
--------------------------------------------------------------------------------------------------------------------------------------------------------
ICR ICRSSL ICRSSM
-------------------------------------------------------------------------------------------------
Total annual
Technology Plants Total annual Plants Total annual Plants energy
selecting energy required selecting energy required selecting required (kWh/
technology (kWh/yr) technology (kWh/yr) technology yr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
A B C D E F
CIO2.................................................. 77 343,297 61 268,861 70 312,036
UV.................................................... 998 86,827,218 490 52,212,046 632 64,515,863
O3 (0.5 log).......................................... 26 12,524,670 19 10,328,359 21 11,467,703
O3 (1.0 log).......................................... 24 12,456,132 12 6,119,824 21 10,759,696
O3 (2.0 log).......................................... 9 7,324,561 0 35,259 2 1,787,144
MF/UF................................................. 10 5,691,144 8 4,507,577 5 2,790,401
Bag Filters........................................... 1,545 1,631,873 1,236 1,306,067 1,441 1,522,243
Cartridge Filters..................................... 190 76,793 17 6,254 52 19,686
-------------------------------------------------------
Total........................................... 2,878 126,875,687 1,844 74,784,249 2,244 93,174,772
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: The LT2ESWTR Economic Analysis (USEPA 2003a).

To determine if the additional energy required for systems to
comply with the rule would have a significant adverse effect on the use
of energy, the numbers in Table VII-5 are compared to the national
production figures for electricity. According to the U.S. Department of
Energy's Information Administration, electricity producers generated
3,800 million mW of electricity in 2001 (USDOE EIA, 2002). Therefore,
even using the highest assumed energy use for the LT2ESWTR, the rule
when fully implemented would result in only a 0.003 percent increase in
annual average energy use.
In addition to average energy use, the impact at times of peak
power demand is important. To examine whether increased energy usage
might significantly affect the capacity margins of energy suppliers,
their peak season generating capacity reserve was compared to an
estimate of peak incremental power demand by water utilities.
Both energy use and water use are highest in the summer months, so
the most significant effects on supply would be seen then. In the
summer of 2001, U.S. generation capacity exceeded consumption by 15
percent, or approximately 120,000 mW (USDOE EIA 2002). Assuming around-
the-clock operation of water treatment plants, the total energy
requirement can be divided by 8,760 hours per year to obtain an average
power demand of 15 mW for the modeled Information Collection Rule
occurrence distribution. A more detailed derivation of this value is
shown in Appendix P of the Economic Analysis for the LT2ESWTR (USEPA
2003a). Assuming that power demand is proportional to water flow
through the plant, and that peak flow can be as high as twice the
average daily flow during the summer months, about 30 mW could be
needed for treatment technologies installed to comply with the
LT2ESWTR. This is only 0.024 percent of the capacity margin available
at peak use.
Although EPA recognizes that not all areas have a 15 percent
capacity margin and that this margin varies across regions and through
time, this analysis reflects the effect of the rule on national energy
supply, distribution, or use. While certain areas, notably California,
have experienced shortfalls in generating capacity in the recent past,
a peak incremental power requirement of 30 mW nationwide is not likely
to significantly change the energy supply, distribution, or use in any
given area. Considering this analysis, EPA has concluded that LT2ESWTR
is not likely to have a significant adverse effect on the supply,
distribution, or use of energy.

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement
Act (NTTAA) of 1995, Public Law 104-113, section 12(d) (15 U.S.C. 272
note), directs EPA to use voluntary consensus standards in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., material specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by voluntary consensus standard bodies. The NTTAA directs EPA
to provide Congress, through OMB, explanations when the Agency decides
not to use available and applicable voluntary consensus standards.

[[Page 47769]]

The proposed rulemaking involves technical standards. EPA proposes
to use several voluntary consensus standards (VCS) methods for
enumerating E. coli in surface waters. These methods are listed in
section IV.K.2, Table IV-37, and were developed or adopted by the
following organizations: American Public Health Association in Standard
Methods for the Examination of Water and Wastewater, 20th, 19th, and
18th Editions, the American Society of Testing Materials in Annual Book
of ASTM Standards--Water and Environmental Technology, and the
Association of Analytical Chemists in Official Methods of Analysis of
AOAC International, 16th Edition. These methods are available in the
docket for today's proposal. EPA has concluded that these methods have
the necessary sensitivity and specificity to meet the data quality
objectives of the LT2ESWTR.
The Agency conducted a search to identify potentially applicable
voluntary consensus standards for analysis of Cryptosporidium. However,
we identified no such standards. Therefore, EPA proposes to use the
following methods for Cryptosporidium analysis: Method 1622:
``Cryptosporidium in Water by Filtration/IMS/FA'' (EPA-821-R-01-026,
April 2001) (USEPA 2001e) and Method 1623: ``Cryptosporidium and
Giardia in Water by Filtration/IMS/FA'' (EPA 821-R-01-025, April 2001)
(USEPA 2001f).
EPA welcomes comments on this aspect of the proposed rulemaking
and, specifically, invites the public to identify additional
potentially applicable voluntary consensus standards, and to explain
why such standards should be used in this regulation.

J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations or Low-Income Populations

Executive Order 12898 establishes a Federal policy for
incorporating environmental justice into Federal agency missions by
directing agencies to identify and address disproportionately high and
adverse human health or environmental effects of its programs,
policies, and activities on minority and low-income populations. The
Agency has considered environmental justice related issues concerning
the potential impacts of this action and consulted with minority and
low-income stakeholders.
Two aspects of the LT2ESWTR comply with the order that requires the
Agency to consider environmental justice issues in the rulemaking and
to consult with stakeholders representing a variety of economic and
ethnic backgrounds. These are: (1) The overall nature of the rule, and
(2) the convening of a stakeholder meeting specifically to address
environmental justice issues.
The Agency built on the efforts conducted during the development of
the IESWTR to comply with Executive Order 12898. On March 12, 1998, the
Agency held a stakeholder meeting to address various components of
pending drinking water regulations and how they might impact sensitive
subpopulations, minority populations, and low-income populations. This
meeting was a continuation of stakeholder meetings that started in 1995
to obtain input on the Agency's Drinking Water Programs. Topics
discussed included treatment techniques, costs and benefits, data
quality, health effects, and the regulatory process. Participants were
national, State, Tribal, municipal, and individual stakeholders. EPA
conducted the meeting by video conference call between eleven cities.
The major objectives for the March 12, 1998, meeting were the
following:

[sbull] Solicit ideas from stakeholders on known issues concerning
current drinking water regulatory efforts;
[sbull] Identify key areas of concern to stakeholders; and
[sbull] Receive suggestions from stakeholders concerning ways to
increase representation of communities in OGWDW regulatory efforts.
In addition, EPA developed a plain-English guide for this meeting
to assist stakeholders in understanding the multiple and sometimes
complex issues surrounding drinking water regulations.
The LT2ESWTR and other drinking water regulations promulgated or
under development are expected to have a positive effect on human
health regardless of the social or economic status of a specific
population. The LT2ESWTR serves to provide a similar level of drinking
water protection to all groups. Where water systems have high
Cryptosporidium levels, they must treat their water to achieve a
specified level of protection. Further, to the extent that levels of
Cryptosporidium in drinking water might be disproportionately high
among minority or low-income populations (which is unknown), the
LT2ESWTR will work to remove those differences. Thus, the LT2ESWTR
meets the intent of Federal policy requiring incorporation of
environmental justice into Federal agency missions.
The LT2ESWTR applies uniformly to CWSs, NTNCWSs, and TNCWSs that
use surface water or GWUDI as their source. Consequently, this rule
provides health protection from pathogen exposure equally to all income
and minority groups served by surface water and GWUDI systems.

K. Consultations with the Science Advisory Board, National Drinking
Water Advisory Council, and the Secretary of Health and Human Services

In accordance with sections 1412 (d) and (e) of SDWA, the Agency
has consulted with the Science Advisory Board (SAB), the National
Drinking Water Advisory Council (NDWAC), and will consult with the
Secretary of Health and Human Services regarding the proposed LT2ESWTR
during the public comment period. EPA charged the SAB panel with
reviewing the following aspects of the LT2ESWTR proposal:
[sbull] The analysis of Cryptosporidium occurrence, as described in
Occurrence and Exposure Assessment for the LT2ESWTR (USEPA 2003b);
[sbull] The pre- and post-LT2ESWTR Cryptosporidium risk assessment,
as described in Economic Analysis for the LT2ESWTR (USEPA 2003a); and
[sbull] The treatment credits for the following four microbial
toolbox components: raw water off-stream storage, pre-sedimentation,
lime softening, and lower finished water turbidity (described in
section IV.C of this preamble).
EPA met with the SAB to discuss the LT2ESWTR on June 13, 2001
(Washington, DC), September 25-26, 2001 (teleconference), and December
10-12, 2001 (Los Angeles, CA). Written comments from the December 2001
meeting of the SAB addressing the occurrence analysis and risk
assessment were generally supportive. EPA has responded to the SAB's
recommendations for Cryptosporidium occurrence analysis in the current
draft of Occurrence and Exposure Assessment for the LT2ESWTR (USEPA
2003b), and EPA has addressed the SAB's comments on risk assessment in
the current draft of Economic Analysis for the LT2ESWTR (USEPA 2003a).
Comments from the SAB on the microbial toolbox components and the
Agency's responses to those comments are described in section IV.C of
this preamble.
EPA met with the NDWAC on November 8, 2001, in Washington, DC, to
discuss the LT2ESWTR proposal. EPA specifically requested comments from
the NDWAC on the regulatory approach taken in the proposed microbial
toolbox (e.g., proposal of specific design and implementation criteria
for treatment credits). The Council was generally supportive of EPA
establishing criteria for awarding

[[Page 47770]]

treatment credit to toolbox components, but recommended that EPA
provide flexibility for States to address system specific situations.
EPA believes that the demonstration of performance credit, described in
section IV.C.17, provides this flexibility by allowing States to award
higher or lower levels of treatment credit for microbial toolbox
components based on site specific conditions. Minutes of the NDWAC and
SAB meetings are in the docket for today's proposal.

L. Plain Language

Executive Order 12866 encourages Federal agencies to write rules in
plain language. EPA invites comments on how to make this proposed rule
easier to understand. For example: Has EPA organized the material to
suit commenters' needs? Are the requirements in the rule clearly
stated? Does the rule contain technical language or jargon that is not
clear? Would a different format (grouping and ordering of sections, use
of headings, paragraphs) make the rule easier to understand? Could EPA
improve clarity by adding tables, lists, or diagrams? What else could
EPA do to make the rule easier to understand?

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List of Subjects

40 CFR Part 141

Environmental protection, Chemicals, Indians-lands,
Intergovernmental relations, Radiation protection, Reporting and
recordkeeping requirements, Water supply.

40 CFR Part 142

Environmental protection, Administrative practice and procedure,
Chemicals, Indians-lands, Radiation protection, Reporting and
recordkeeping requirements, Water supply.

Dated: July 11, 2003.
Linda J. Fisher,
Acting Administrator.
For the reasons set forth in the preamble, title 40 chapter I of
the Code of Federal Regulations is proposed to be amended as follows:

PART 141--NATIONAL PRIMARY DRINKING WATER REGULATIONS

1. The authority citation for Part 141 continues to read as
follows:

Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9, and 300j-11.

2. Section 141.2 is amended by adding, in alphabetical order,
definitions for Bag filters, Bank filtration, Cartridge filters,
Flowing stream, Lake/reservoir, Membrane filtration, Off-stream raw
water storage, Plant intake, Presedimentation, and Two-stage lime
softening to read as follows:

Sec. 141.2 Definitions.

* * * * *
Bag filters are pressure-driven separation devices that remove
particulate matter larger than 1 [mu]m using an engineered porous
filtration media through either surface or depth filtration. Bag
filters are typically constructed of a non-rigid, fabric filtration
media housed in a pressure vessel in which the direction of flow is
from the inside of the bag to outside.
Bank filtration is a water treatment process that uses a pumping
well to recover surface water that has naturally infiltrated into
ground water through a river bed or bank(s). Infiltration is typically
enhanced by the hydraulic gradient imposed by a nearby pumping water
supply or other well(s).
* * * * *
Cartridge filters are pressure-driven separation devices that
remove particulate matter larger than 1 [mu]m using an engineered
porous filtration media through either surface or depth filtration.
Cartridge filters are typically constructed as rigid or semi-rigid,
self-supporting filter elements housed in pressure vessels in which
flow is from the outside of the cartridge to the inside.
* * * * *
Flowing stream is a course of running water flowing in a definite
channel.
* * * * *
Lake/reservoir refers to a natural or man made basin or hollow on
the Earth's surface in which water collects or is stored that may or
may not have a current or single direction of flow.
* * * * *
Membrane filtration is a pressure-driven or vacuum-driven
separation process in which particulate matter larger than 1 [mu]m is
rejected by an engineered barrier primarily through a size exclusion
mechanism, and which has a measurable removal efficiency of a target
organism that can be verified through the application of a direct
integrity test. This definition includes the common membrane
technologies of microfiltration (MF), ultrafiltration (UF),
nanofiltration (NF), and reverse osmosis (RO).
* * * * *
Off-stream raw water storage refers to an impoundment in which
water is stored prior to treatment and from which outflow is
controlled.
* * * * *
Plant intake refers to the works or structures at the head of a
conduit through which water is diverted from a source (e.g., river or
lake) into the treatment plant.
* * * * *
Presedimentation is a preliminary unit process used to remove
gravel, sand and other particulate material from the source water
through settling before it enters the main treatment plant.
* * * * *
Two-stage lime softening refers to a process for the removal of
hardness by the addition of lime and consisting of two distinct unit
clarification processes in series prior to filtration.
* * * * *
3. Appendix A to Subpart Q of part 141 is amended in section I,
Part A by adding entry number 10:
Subpart Q--Public Notification of Drinking Water Violations.

Appendix A to Subpart Q of Part 141--NPDWR Violations and Other Situations Requiring Public Notice \1\
----------------------------------------------------------------------------------------------------------------
MCL/MRDL/TT violations \2\ Monitoring and testing procedure
--------------------------------------- violations
--------------------------------------
Contaminant Tier of public Tier of public
notice Citation notice Citation
required required
----------------------------------------------------------------------------------------------------------------
I. Violations of National Primary
Drinking Water Regulations
(NPDWR) \3\:
A. Microbiological Contaminants

[[Page 47776]]

* * * * * * *
10. LT2ESWTR violations........... 2 141.720-141.729...... 3 141.701-141.707;
141.711-141.713;
141.730

* * * * * * *
----------------------------------------------------------------------------------------------------------------
\1\Violations and other situations not listed in this table (e.g., reporting violations and failure to prepare
Consumer Confidence Reports) do not require notice, unless otherwise determined by the primary agency. Primary
agencies may, at their option, also require a more stringent public notice tier (e.g., Tier 1 instead of Tier
2 or Tier 2 instead of Tier 3) for specific violations and situations listed in this Appendix, as authorized
under Sec. 141.202(a) and Sec. 141.203(a).
\2\ MCL--Maximum contaminant level, MRDL--Maximum residual disinfectant level, TT--Treatment technique
\3\ The term Violations of National Primary Drinking Water Regulations (NPDWR) is used here to include
violations of MCL, MRDL, treatment technique, monitoring, and testing procedure requirements.

4. Part 141 is amended by adding a new subpart W to read as
follows:
Subpart W--Enhanced Filtration and Disinfection for Cryptosporidium

General Requirements

141.700 Applicability.
141.701 General requirements.

Source Water Monitoring Requirements

141.702 Source water monitoring.
141.703 Sampling schedules.
141.704 Sampling locations.
141.705 Analytical methods.
141.706 Requirements for use of an approved laboratory.
141.707 Reporting source water monitoring results.
141.708 Previously collected data.
141.709 Bin classification for filtered systems.

Disinfection Profiling and Benchmarking Requirements

141.710 [Reserved]
141.711 Determination of systems required to profile.
141.712 Schedule for disinfection profiling requirements.
141.713 Developing a profile.
141.714 Requirements when making a significant change in
disinfection practice.

Treatment Technique Requirements

141.720 Treatment requirements for filtered systems.
141.721 Treatment requirements for unfiltered systems.
141.722 Microbial toolbox options for meeting Cryptosporidium
treatment requirements.
141.723 [Reserved]
141.724 Requirements for uncovered finished water storage
facilities.

Requirements for Microbial Toolbox Components

141.725 Source toolbox components.
141.726 Pre-filtration treatment toolbox components.
141.727 Treatment performance toolbox components.
141.728 Additional filtration toolbox components.
141.729 Inactivation toolbox components.

Reporting and Recordkeeping Requirements

141.730 Reporting requirements.
141.731 Recordkeeping requirements.

Subpart W--Enhanced Filtration and Disinfection for Cryptosporidium

General Requirements

Sec. 141.700 Applicability.

The requirements of this subpart apply to all subpart H systems.
Failure to comply with any requirement of this subpart is a violation
and requires public notification.

Sec. 141.701 General requirements.

(a) All subpart H systems, including wholesale systems, must
characterize their source water to determine what (if any) additional
treatment is necessary for Cryptosporidium, unless they meet the
criteria in either paragraph (f) or (g) of this section.
(b) Systems serving at least 10,000 people that currently provide
filtration or that are unfiltered and required to install filtration
must conduct source water monitoring that includes Cryptosporidium, E.
coli, and turbidity sampling and comply with the treatment requirements
in Sec. 141.720.
(c) Systems serving fewer than 10,000 people that currently provide
filtration or that are unfiltered and required to install filtration
must conduct source water monitoring consisting of E. coli sampling or
sampling of an alternative indicator approved by the State. If the
annual mean concentration of E. coli exceeds the levels specified in
Sec. 141.702(b), or if the level of a State-approved alternate
indicator exceeds a State-approved alternative indicator trigger level,
systems must conduct Cryptosporidium monitoring to complete the source
water monitoring requirements and comply with the treatment
requirements in Sec. 141.720.
(d) Systems that are unfiltered and meet all the filtration
avoidance criteria of Sec. 141.71 must conduct source water monitoring
consisting of Cryptosporidium sampling and comply with the treatment
requirements in Sec. 141.721.
(e) Systems must comply with the requirements in this subpart based
on the schedule in the following table, except that systems are not
required to conduct source water monitoring if they meet the criteria
in paragraph (f) of this section for systems that currently provide
filtration or that are unfiltered and required to install filtration or
paragraph (g) of this section for systems that are unfiltered and meet
all the filtration avoidance criteria of Sec. 141.71:

[[Page 47777]]

Compliance Requirements Table
------------------------------------------------------------------------
Must perform . . And comply by . .
Systems that are . . . .\a,b\ .
------------------------------------------------------------------------
(1) Subpart H systems serving (i) 24 months of Submitting a
=10,000 people that source water monthly report to
currently provide filtration or monitoring for EPA no later than
that are unfiltered and Cryptosporidium, ten days after
required to install filtration. E. coli and the end of the
turbidity at first month
least once each following the
month beginning month when the
no later than sample is taken.
[Date 6 Months
After Date of
Publication of
Final Rule in the
Federal Register].
(ii) Treatment Installing
technique treatment and
implementation, complying with
if necessary. the treatment
technique no
later than [Date
72 Months After
Date of
Publication of
Final Rule in the
Federal Register]
\c\.
(2) Subpart H systems serving (i) 24 months of Submitting a
=10,000 people that source water monthly report to
are unfiltered and meet the monitoring for EPA no later than
filtration avoidance criteria Cryptosporidium ten days after
of Sec. 141.71. at least once the end of the
each month first month
beginning no following the
later than [Date month when the
6 Months After sample is taken.
Date of
Publication of
Final Rule in the
Federal Register].
(ii) Treatment Installing
technique treatment and
implementation, complying with
if necessary. the treatment
technique no
later than [Date
72 Months After
Date of
Publication of
Final rule in the
Federal Register]
\c\.
(3) Subpart H systems serving 12 months of Submitting a
<10,000 people that currently source water monthly report to
provide filtration or that are monitoring for E. the State no
unfiltered and required to coli at least later than ten
install filtration and are not once every two days after the
required to monitor for weeks beginning end of the first
Cryptosporidium based on E. no later than month following
coli or other indicator [Date 30 Months the month when
monitoring results \d\. After Date of the sample is
Publication of taken.
Final Rule in the
Federal Register].
(4) Subpart H systems serving (i) 12 months of Submitting a
<10,000 people that currently source water monthly report to
provide filtration or that are monitoring for E. the State no
unfiltered and required to coli at least later than ten
install filtration and must once every two days after the
perform Cryptosporidium weeks beginning end of the first
monitoring based on E. coli or no later than month following
other indicator monitoring [Date 30 Months the month when
results \d\. After Date of the sample is
Publication of taken.
Final Rule in the
Federal Register]
and 12 months of
source water
monitoring for
Cryptosporidium
at least twice
each month
beginning no
later than [Date
48 Months After
Date of
Publication of
Final Rule in the
Federal Register].
(ii) Treatment Installing
technique treatment and
implementation, complying with
if necessary. the treatment
technique no
later than [Date
102 Months After
Date of
Publication of
Final Rule in the
Federal Register]
\c\.
(5) Subpart H systems serving (i) 12 months of Submitting a
<10,000 people that are source water monthly report to
unfiltered and meet the monitoring for the State no
filtration avoidance criteria Cryptosporidium later than ten
of Sec. 141.71. at least twice days after the
each month end of the first
beginning no month following
later than [Date the month when
48 Months After the sample is
Date of taken.
Publication of
Final Rule in the
Federal Register].
(ii) Treatment Installing
technique treatment and
implementation, complying with
if necessary. the treatment
technique no
later than [Date
102 Months After
Date of
Publication of
Final Rule in the
Federal Register]
\c\.
------------------------------------------------------------------------
\a\ Any sampling performed more frequently than required must be evenly
distributed over the sampling period.
\b\ Systems may use data that meet the requirements in Sec. 141.708
collected prior to the monitoring start date to substitute for an
equivalent number of months at the end of the monitoring period.
\c\ States may allow up to an additional two years for complying with
the treatment technique requirement for systems making capital
improvements.
\d\ See Sec. 141.702(b) to determine if Cryptosporidium monitoring is
required.

(f) Systems that currently provide filtration or that are
unfiltered and required to install filtration are not required to
conduct source water monitoring under this subpart if the system
currently provides or will provide a total of at least 5.5 log of
treatment for Cryptosporidium, equivalent to meeting the treatment
requirements of Bin 4 in Sec. 141.720. Systems must notify the State
not later than the date the system is otherwise required to submit a
sampling schedule for monitoring under Sec. 141.703 and must install
and operate technologies to provide a total of at least 5.5 log of
treatment for Cryptosporidium by the applicable date in paragraph (e)
of this section.
(g) Systems that are unfiltered and meet all the filtration
avoidance criteria of Sec. 141.71 are not required to conduct source
water monitoring under this subpart if the system currently provides or
will provide a total of at least 3 log Cryptosporidium inactivation,
equivalent to meeting the treatment requirements for unfiltered systems
with a mean Cryptosporidium concentration of greater than 0.01 oocysts/
L in Sec. 141.721. Systems must notify the State not later than the
date the system is otherwise required to submit a sampling schedule for
monitoring under Sec. 141.703. Systems must install and operate
technologies to provide a total of at least 3 log Cryptosporidium
inactivation by the applicable date in paragraph (e) of this section.
(h) Systems must comply with the uncovered finished water storage
facility requirements in Sec. 141.724 no later than [Date 36 Months
After Date of Publication of Final Rule in the Federal Register].

[[Page 47778]]

Source Water Monitoring Requirements

Sec. 141.702 Source water monitoring.

(a) Systems must conduct initial source water monitoring as
specified in Sec. 141.701(b) through (f).
(b) Systems serving fewer than 10,000 people that provide
filtration or that are unfiltered and required to install filtration
must perform Cryptosporidium monitoring in accordance with Sec.
141.701(e) if they meet any of the criteria in paragraphs (b)(1)
through (4) of this section.
(1) For systems using lake/reservoir sources, an annual mean E.
coli concentration greater than 10 E. coli/100 mL, based on monitoring
conducted under this section, unless the State approves an alternative
indicator trigger.
(2) For systems using flowing stream sources, an annual mean E.
coli concentration greater than 50 E. coli/100 mL, based on monitoring
conducted under this section, unless the State approves an alternative
indicator trigger.
(3) If the State approves an alternative to the indicator trigger
in paragraph (b)(1) or (b)(2) of this section, an annual concentration
that exceeds a State-approved trigger level, including an alternative
E. coli level, based on monitoring conducted under this section.
(4) The system does not conduct E. coli or other State-approved
indicator monitoring as specified in Sec. 141.701(e).
(c) Systems may submit Cryptosporidium data collected prior to the
monitoring start date to meet the initial source water monitoring
requirements of paragraphs (a) through (b) of this section. Systems may
also use Cryptosporidium data collected prior to the monitoring start
date to substitute for an equivalent number of months at the end of the
monitoring period. All data submitted under this paragraph must meet
the requirements in Sec. 141.708.
(d) Systems must conduct a second round of source water monitoring
in accordance with the requirements in Sec. 141.701(b) through (e) of
this section, beginning no later than the dates specified in paragraphs
(d)(1) through (3) of this section, unless they meet the criteria in
either paragraph Sec. 141.701(f) or (g).
(1) Systems that serve at least 10,000 people must begin a second
round of source water monitoring no later than [Date 108 Months After
Date of Publication of Final Rule in the Federal Register].
(2) Systems serving fewer than 10,000 people that provide
filtration or that are unfiltered and required to install filtration
must begin a second round of source water monitoring no later than
[Date 138 Months After Date of Publication of Final Rule in the Federal
Register] and, if required to monitor for Cryptosporidium under
paragraph (b) of this section, must begin Cryptosporidium monitoring no
later than [Date 156 Months After Date of Publication of Final Rule in
the Federal Register].
(3) Systems serving fewer than 10,000 people that are unfiltered
and meet the filtration avoidance requirements of Sec. 141.71 must
begin a second round of source water monitoring no later than [Date 156
Months After Date of Publication of Final Rule in the Federal
Register].

Sec. 141.703 Sampling schedules.

(a) Systems required to sample under Sec. Sec. 141.701 through
141.702 must submit a sampling schedule that specifies the calendar
dates that all required samples will be taken.
(1) Systems serving at least 10,000 people must submit their
sampling schedule for initial source water monitoring to EPA
electronically at [insert Internet address] no later than [Date 3
Months After Date of Publication of Final Rule in the Federal
Register].
(2) Systems serving fewer than 10,000 people that are filtered or
that are unfiltered and required to install filtration must submit a
sampling schedule for initial source water monitoring of E. coli or an
alternative State-approved indicator to the State no later than [Date
27 Months After Date of Publication of Final Rule in the Federal
Register].
(3) Filtered systems serving fewer than 10,000 people that are
required to conduct Cryptosporidium monitoring and unfiltered systems
serving fewer than 10,000 people must submit a sampling schedule for
initial source water Cryptosporidium monitoring to the State no later
than [Date 45 Months After Date of Publication of Final Rule in the
Federal Register].
(4) Systems must submit a sampling schedule for the second round of
source water monitoring to the State no later than 3 months prior to
the date the system is required to begin the second round of monitoring
under Sec. 141.702(d).
(b) Systems must collect samples within two days of the dates
indicated in their sampling schedule.
(c) If extreme conditions or situations exist that may pose danger
to the sample collector, or which are unforeseen or cannot be avoided
and which cause the system to be unable to sample in the required time
frame, the system must sample as close to the required date as feasible
and submit an explanation for the alternative sampling date with the
analytical results.
(d) Systems that are unable to report a valid Cryptosporidium
analytical result for a scheduled sampling date due to failure to
comply with the analytical method requirements, including the quality
control requirements in Sec. 141.705, must collect a replacement
sample within 14 days of being notified by the laboratory or the State
that a result cannot be reported for that date and must submit an
explanation for the replacement sample with the analytical results.

Sec. 141.704 Sampling locations.

(a) Unless specified otherwise in this section, systems required to
sample under Sec. Sec. 141.701 through 141.702 must collect source
water samples from the plant intake prior to any treatment. Where
treatment is applied in an intake pipe such that sampling in the pipe
prior to treatment is not feasible, systems must collect samples as
close to the intake as is feasible, at a similar depth and distance
from shore.
(b) Presedimentation. Systems using a presedimentation basin must
collect source water samples after the presedimentation basin but
before any other treatment. Use of presedimentation basins during
monitoring must be consistent with routine operational practice and the
State may place reporting requirements to verify operational practices.
Systems collecting samples after a presedimentation basin may not
receive credit for the presedimentation basin under Sec. 141.726(a).
(c) Raw water off-stream storage. Systems using an off-stream raw
water storage reservoir must collect source water samples after the
off-stream storage reservoir. Use of off-stream storage during
monitoring must be consistent with routine operational practice and the
State may place reporting requirements to verify operational practices.
(d) Bank filtration. The required sampling location for systems
using bank filtration differs depending on whether the bank filtered
water is treated by subsequent filtration for compliance with Sec.
141.173(b) or Sec. 141.552(a), as applicable.
(1) Systems using bank filtered water that is treated by subsequent
filtration for compliance with Sec. 141.173(b) or Sec. 141.552(a), as
applicable, must collect source water samples from the well (i.e.,
after bank filtration), but before any other treatment. Use of bank
filtration during monitoring must be consistent with routine
operational practice and the State may place reporting

[[Page 47779]]

requirements to verify operational practices. Systems collecting
samples after a bank filtration process may not receive credit for the
bank filtration under Sec. 141.726(c).
(2) Systems using bank filtration as an alternative filtration
demonstration to meet their Cryptosporidium removal requirements under
Sec. 141.173(b) or Sec. 141.552(a), as applicable, must collect
source water samples in the surface water (i.e., prior to bank
filtration).
(3) Systems using a ground water source under the direct influence
of surface water that meet all the criteria for avoiding filtration in
Sec. 141.71 and that do not provide filtration treatment must collect
source water samples from the ground water (e.g., the well).
(e) Multiple sources. Systems with plants that use multiple water
sources at the same time, including multiple surface water sources and
blended surface water and ground water sources, must collect samples as
specified in paragraph (e)(1) or (2) of this section. The use of
multiple sources during monitoring must be consistent with routine
operational practice and the State may place reporting requirements to
verify operational practices.
(1) If a sampling tap is available where the sources are combined
prior to treatment, the sample must be collected from the tap.
(2) If there is not a sampling tap where the sources are combined
prior to treatment, systems must collect samples at each source near
the intake on the same day and must follow either paragraph (e)(2)(i)
or (e)(2)(ii) of this section for sample analysis.
(i) Composite samples from each source into one sample prior to
analysis. In the composite, the volume of sample from each source must
be weighted according to the proportion of the source in the total
plant flow at the time the sample is collected.
(ii) Analyze samples from each source separately as specified in
Sec. 141.705, and calculate a weighted average of the analysis results
for each sampling date. The weighted average must be calculated by
multiplying the analysis result for each source by the fraction the
source contributed to total plant flow at the time the sample was
collected, and then summing these values.

Sec. 141.705 Analytical methods.

(a) Cryptosporidium. Systems must use Method 1622 Cryptosporidium
in Water by Filtration/IMS/FA, EPA 821-R-01-026, April 2001, or Method
1623 Cryptosporidium and Giardia in Water by Filtration/IMS/FA, EPA
821-R-01-025, April 2001, for Cryptosporidium analysis.
(1) Systems are required to analyze at least a 10 L sample or a
packed pellet volume of at least 2 mL as generated by the methods
listed in paragraph (a) of this section. Systems unable to process a 10
L sample must analyze as much sample volume as can be filtered by two
filters approved by EPA for the methods listed in paragraph (a) of this
section, up to a packed pellet volume of 2 mL.
(2)(i) Matrix spikes (MS) samples as required by the methods in
paragraph (a) of this section must be spiked and filtered by a
laboratory approved for Cryptosporidium analysis under Sec. 141.706.
The volume of the MS sample must be within 10 percent of the volume of
the unspiked sample that is collected at the same time, and the samples
must be collected by splitting the sample stream or collecting the
samples sequentially. The MS sample and the associated unspiked sample
must be analyzed by the same procedure.
(ii) If the volume of the MS sample is greater than 10 L, the
system is permitted to filter all but 10 L of the MS sample in the
field, and ship the filtered sample and the remaining 10 L of source
water to the laboratory. In this case, the laboratory must spike the
remaining 10 L of water and filter it through the filter used to
collect the balance of the sample in the field.
(3) Each sample batch must meet the quality control criteria for
the methods listed in paragraph (a) of this section. Flow cytometer-
counted spiking suspensions must be used for MS samples and ongoing
precision and recovery (OPR) samples; recovery for OPR samples must be
11% to 100%; for each method blank, oocysts must not be detected.
(4) Total Cryptosporidium oocysts as detected by fluorescein
isothiocyanate (FITC) must be reported as determined by the color
(apple green or alternative stain color approved under Sec. 141.706(a)
for the laboratory), size (4-6 [mu]m) and shape (round to oval). This
total includes all of the oocysts identified, less any atypical
organisms identified by FITC, differential interference contrast (DIC)
or 4',6-diamindino-2-phenylindole (DAPI), including those possessing
spikes, stalks, appendages, pores, one or two large nuclei filling the
cell, red fluorescing chloroplasts, crystals, and spores.
(b) E. coli. Systems must use the following methods listed in this
paragraph for enumeration of E. coli in source water (table will be
replaced with CFR cite from Guidelines Establishing Test Procedures for
the Analysis of Pollutants; Analytical Methods for Biological
Pollutants in Ambient Water when finalized--expected 2003):

Methods for E. coli Enumeration \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
VCSB methods
Technique Method \1\ EPA ------------------------------------------------------------------
Standard methods ASTM AOAC
--------------------------------------------------------------------------------------------------------------------------------------------------------
Most Probable Number (MPN).......... LTB, EC-MUG............ ...................... 9221B.1/9221F
ONPG-MUG............... ...................... 9223B ...................... 991.15
ONPG-MUG............... ...................... 9223B
Membrane Filter (MF)................ mFCNA-MUG..... ...................... 9222D/9222G
ENDONA-MUG.... ...................... 9222B/9222G
mTEC agar.............. 1103.1................ 9213D D5392-93
Modified mTEC agar..... Modified 1103.1
MI agar................ EPA-600-R-013
m-ColiBlue24 broth
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Tests must be conducted in a format that provides organism enumeration.

XXXXXXXXXXXXXXXXXXXXXX(1) The time from sample collection to
initiation of analysis may not exceed 24 hours. Systems must maintain
samples between 0[deg]C and 10[deg]C during transit.
(2) [Reserved]
(c) Turbidity. Systems must use methods for turbidity measurement
approved in Sec. 141.74.

[[Page 47780]]

Sec. 141.706 Requirements for use of an approved laboratory.

(a) Cryptosporidium. Systems must have Cryptosporidium samples
analyzed by a laboratory that has passed a quality assurance evaluation
under EPA's Laboratory Quality Assurance Evaluation Program for
Analysis of Cryptosporidium in Water or a laboratory that has been
certified for Cryptosporidium analysis by an equivalent State
laboratory certification program.
(b) E. coli. Any laboratory certified by the EPA, the National
Environmental Laboratory Accreditation Conference or the State for
total coliform or fecal coliform analysis in source water under Sec.
141.74 is deemed approved for E. coli analysis under this subpart when
the laboratory uses the same technique for E. coli that the laboratory
uses for source water in Sec. 141.74.
(c) Turbidity. Measurements of turbidity must be made by a party
approved by the State.

Sec. 141.707 Reporting source water monitoring results.

(a) All systems serving at least 10,000 people must submit the
results of all initial source water monitoring required under Sec.
141.702(a) to EPA electronically at [insert Internet address]. Systems
that do not have the ability to submit data electronically may use an
alternative format approved by EPA.
(b) Systems serving fewer than 10,000 people must submit the
results of all initial source water monitoring required under Sec.
141.702(a)-(b) to the State.
(c) All systems must submit the results from the second round of
source water monitoring required under Sec. 141.702(d) to the State.
(d) Source water monitoring analysis results must be submitted not
later than ten days after the end of first month following the month
when the sample is collected. The submission must include the
applicable information in paragraphs (e)(1) and (2) of this section.
(e)(1) Systems must report the following data elements for each
Cryptosporidium analysis:

(i) PWS ID
(ii) Facility ID
(iii) Sample collection point
(iv) Sample collection date
(v) Sample type (field or matrix spike)
(vi) Sample volume filtered (L), to nearest \1/4\ L
(vii) Was 100% of filtered volume examined
(viii) Number of oocysts counted
(i) For matrix spike samples, systems must also report the sample
volume spiked and estimated number of oocysts spiked. These data are
not required for field samples.
(ii) For samples in which less than 10 L is filtered or less than
100% of the sample volume is examined, systems must also report the
number of filters used and the packed pellet volume.
(iii) For samples in which less than 100% of sample volume is
examined, systems must also report the volume of resuspended
concentrate and volume of this resuspension processed through
immunomagnetic separation.
(2) Systems must report the following data elements for each E.
coli analysis:

(i) PWS ID
(ii) Facility ID
(iii) Sample collection point
(iv) Sample collection date
(v) Analytical method number
(vi) Method type
(vii) Source type
(viii) E. coli/100 mL
(ix) Turbidity (Systems serving fewer than 10,000 people that are not
required to monitor for turbidity under Sec. 141.701(c) are not
required to report turbidity with their E. coli results.)

Sec. 141.708 Previously collected data.

(a) Systems may comply with the initial monitoring requirements of
Sec. 141.702(a) using Cryptosporidium data collected before the system
is required to begin monitoring if the system meets the conditions in
paragraphs (b) through (h) of this section and EPA notifies the system
that the data are acceptable.
(b) To be accepted, previously collected Cryptosporidium data must
meet the conditions in paragraphs (b)(1) through (5) of this section.
(1) Samples were analyzed by laboratories using one of the
analytical methods in paragraphs (b)(1)(i) through (iv) of this
section.
(i) Method 1623: Cryptosporidium and Giardia in Water by
Filtration/IMS/FA, 2001, EPA-821-R-01-025.
(ii) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA,
2001, EPA-821-R-01-026.
(iii) Method 1623: Cryptosporidium and Giardia in Water by
Filtration/IMS/FA, 1999, EPA-821-R-99-006.
(iv) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA,
1999, EPA-821-R-99-001.
(2) Samples were collected no less frequently than each calendar
month on a regular schedule, beginning no earlier than January 1999.
(3) Samples were collected in equal intervals of time over the
entire collection period (e.g., weekly, monthly). Sample collection
interval may vary for the conditions specified in Sec. 141.703(c) and
(d) if the system provides documentation of the condition.
(4) Samples met the conditions for sampling location specified in
Sec. 141.704. The system must report the use of bank filtration,
presedimentation, and raw water off-stream storage during sampling.
(5) For each sample, the laboratory analyzed at least 10 L of
sample or at least 2 mL of packed pellet or as much volume as could be
filtered by 2 filters approved by EPA for the methods listed in
paragraph (b)(1) of this section, up to a packed pellet volume of 2 mL.
(c) The system must submit a letter to EPA concurrent with the
submission of previously collected data certifying that the data meet
the conditions in paragraphs (c)(1) and (2) of this section.
(1) The reported Cryptosporidium analysis results include all
results generated by the system during the time period beginning with
the first reported result and ending with the final reported result.
This applies to samples that were collected from the sampling location
specified for source water monitoring under this subpart, not spiked,
and analyzed using the laboratory's routine process for the analytical
methods listed in paragraph (a)(1) of this section.
(2) The samples were representative of a plant's source water(s)
and the source water(s) have not changed.
(d) For each sample, the system must report the data elements in
Sec. 141.707(e)(1).
(e) The laboratory or laboratories that generated the data must
submit a letter to EPA concurrent with the submission of previously
collected data certifying that the quality control criteria specified
in the methods listed in paragraph (b)(1) of this section were met for
each sample batch associated with the previously collected data.
Alternatively, the laboratory may provide bench sheets and sample
examination report forms for each field, matrix spike, IPR, OPR, and
method blank sample associated with the previously collected data.
(f) If a system has at least two years of Cryptosporidium data
collected before [Date of Publication of Final Rule in the Federal
Register] and the system intends to use these data to comply with the
initial source water monitoring required under Sec. 141.702(a) in lieu
of conducting new monitoring, the system must submit to EPA, no later
than [Date 2 Months After Date of Publication of Final Rule in the
Federal Register], the previously collected data and the supporting
information specified in this section. EPA will notify the system by
[Date 4 Months After Date of Publication of Final Rule in the Federal
Register] as to whether the data are acceptable. If EPA does not notify
the system that the

[[Page 47781]]

submitted data are acceptable, the system must carry out initial source
water as specified in Sec. Sec. 141.701 through 141.707 until EPA
notifies the system that it has at least two years of acceptable data.
(g) If a system has fewer than two years of Cryptosporidium data
collected before [Date of Publication of Final Rule in the Federal
Register] and the system intends to use these data to meet, in part,
the initial source water monitoring required under Sec. 141.702(a),
the system must submit to EPA, no later than [Date 8 Months After Date
of Publication of Final Rule in the Federal Register], the previously
collected data and the supporting information specified in this
section. The system must carry out initial source water monitoring
according to the requirements in Sec. Sec. 141.701 through 141.707
until EPA notifies the system that it has at least two years of
acceptable data.
(h) If a system has two or more years of previously collected data
and the system intends to use these data to comply with the initial
source water monitoring required under Sec. 141.702(a), but the system
also intends to carry out additional initial source water monitoring in
order to base its determination of average Cryptosporidium
concentration under Sec. 141.709 or Sec. 141.721 on more than two
years of monitoring data, the system must submit to EPA, no later than
[Date 8 Months After Date of Publication of Final Rule in the Federal
Register], the previously collected data and the supporting information
specified in this section. The system must carry out initial source
water monitoring according to the requirements in Sec. Sec. 141.701
through 141.707 until EPA notifies the system that it has at least two
years of acceptable data.

Sec. 141.709 Bin classification for filtered systems.

(a) Following completion of the initial source water monitoring
required under Sec. 141.702(a), filtered systems and unfiltered
systems that are required to install filtration must calculate their
initial Cryptosporidium bin concentration using the Cryptosporidium
results reported under Sec. 141.702(a), along with any previously
collected data that satisfy the requirements of Sec. 141.708, and
following the procedures in paragraphs (b)(1) through (3) of this
section.
(b)(1) For systems that collect a total of at least 48 samples, the
Cryptosporidium bin concentration is equal to the arithmetic mean of
all sample concentrations.
(2) For systems that serve at least 10,000 people and collect a
total of at least 24 samples, but not more than 47 samples, the
Cryptosporidium bin concentration is equal to the highest arithmetic
mean of all sample concentrations in any 12 consecutive months during
which Cryptosporidium samples were collected.
(3) For systems that serve fewer than 10,000 people and take at
least 24 samples, the Cryptosporidium bin concentration is equal to the
arithmetic mean of all sample concentrations.
(c) Filtered systems and unfiltered systems that are required to
install filtration must determine their initial bin classification from
the following table and using the Cryptosporidium bin concentration
calculated under paragraph (a) of this section:

Bin Classification Table for Filtered Systems
------------------------------------------------------------------------
With a
Cryptosporidium bin The bin
For systems that are: concentration of . classification is
. .\1\ . . .
------------------------------------------------------------------------
* * * required to monitor for Cryptosporidium < Bin 1
Crypto[chyph]sporidium under 0.075 oocyst/L.
Sec. Sec. 141.701 to 141.702.
0.075 oocysts/L Bin 2
<=Cryptosporidium
< 1.0 oocysts/L.
1.0 oocysts/L <= Bin 3
Cryptosporidium <
3.0 oocysts/L.
Cryptosporidium = 3.0
oocysts/L.
* * * serving fewer than 10,000 NA................. Bin 1
people and NOT required to
monitor for Cryptosporidium
under Sec. 142.702(b).
------------------------------------------------------------------------
\1\ Based on calculations in paragraph (a) or (d) of this section, as
applicable.

(d) Following completion of the second round of source water
monitoring required under Sec. 141.702(d), filtered systems and
unfiltered systems that are required to install filtration must
recalculate their Cryptosporidium bin concentration using the
Cryptosporidium results reported under Sec. 141.702(d) and following
the procedures in paragraphs (b)(1) through (3) of this section.
Systems must then determine their bin classification a second time
using this Cryptosporidium bin concentration and the table in paragraph
(c) of this section.
(e) Any filtered system or unfiltered system that is required to
install filtration that fails to complete the monitoring requirements
of Sec. Sec. 141.701 through 141.707 or choses not to monitor
pursuant to Sec. 141.701(f) must meet the treatment requirements for
Bin 4 under Sec. 141.720 by the date applicable under Sec.
141.701(e).

Disinfection Profiling and Benchmarking Requirements

Sec. 141.710 [Reserved].

Sec. 141.711 Determination of systems required to profile.

(a) Subpart H of this part community and nontransient noncommunity
water systems serving at least 10,000 people that do not have at least
5.5 log of Cryptosporidium treatment, equivalent to compliance with Bin
4 in Sec. 141.720, in place prior to the date when the system is
required to begin profiling in Sec. 141.712 are required to develop
Giardia lamblia and virus disinfection profiles.
(b) Subpart H community and nontransient noncommunity water systems
serving fewer than 10,000 people that do not have at least 5.5 log of
Cryptosporidium treatment, equivalent to compliance with Bin 4 in Sec.
141.720, in place prior to the date when the system is required to
begin profiling in Sec. 141.712 are required to develop Giardia
lamblia and virus disinfection profiles if any of the criteria in
paragraphs (b)(1) through (3) of this section apply.
(1) TTHM levels in the distribution system are at least 0.064 mg/L
as a locational running annual average (LRAA) at any monitoring site.
Systems must base their TTHM LRAA calculation on data collected for
compliance under subpart L of this part after [Date of Publication of
Final Rule in the Federal Register], or as determined by the State.

[[Page 47782]]

(2) HAA5 levels in the distribution system are at least 0.048 mg/L
as an LRAA at any monitoring site. Systems must base their HAA5 LRAA
calculation on data collected for compliance under subpart L of this
part after [Date of Publication of Final Rule in the Federal Register],
or as determined by the State.
(3) The system is required to monitor for Cryptosporidium under
Sec. 141.701(c).
(c) In lieu of developing a new profile, systems may use the
profile(s) developed under Sec. 141.172 or Sec. Sec. 141.530 through
141.536 if the profile(s) meets the requirements of Sec. 141.713(c).

Sec. 141.712 Schedule for disinfection profiling requirements.

(a) Systems must comply with the following schedule in the table in
this paragraph:

Schedule of Required Disinfection Profiling Milestones \1\
----------------------------------------------------------------------------------------------------------------
Date
--------------------------------------------------------------------------
Subpart H systems serving fewer than 10,000
Activity Subpart H systems people
serving at least 10,000 -------------------------------------------------
people Required to monitor for Not required to monitor
Cryptosporidium for Cryptosporidium
----------------------------------------------------------------------------------------------------------------
1. Report TTHM and HAA5 LRAA results NA..................... NA..................... [Date 42 Months After
to State. Date of Publication of
Final Rule in the
Federal Register].
2. Begin disinfection profiling \1,2\ [Date 24 Months After [Date 54 Months After [Date 42 Months After
Date of Publication of Date of Publication of Date of Publication of
Final Rule in the Final Rule in the Final Rule in the
Federal Register]. Federal Register]. Federal Register] if
required \3\.
3. Complete disinfection profiling [Date 36 Months After [Date 66 Months After [Date 54 Months After
based on at least one year of data. Date of Publication of Date of Publication of Date of Publication of
Final Rule in the Final Rule in the Final Rule in the
Federal Register]. Federal Register]. Federal Register] if
required \3\.
----------------------------------------------------------------------------------------------------------------
\1\ Systems with at least 5.5 log of Cryptosporidium treatment in place are not required to do disinfection
profiling.
\2\ Systems may use existing operational data and profiles as described in Sec. 141.713(c).
\3\ Systems serving fewer than 10,000 people are not required to conduct disinfection profiling if they are not
required to monitor for Cryptosporidium and if their TTHM and HAA5 LRAAs do not exceed the levels specified in
Sec. 141.711(b).

(b) [Reserved]

Sec. 141.713 Developing a profile.

(a) Systems required to develop disinfection profiles under Sec.
141.711 must follow the requirements of this section. Systems must
monitor at least weekly for a period of 12 consecutive months to
determeine the total log inactivation for Giardia lamblia and viruses.
Systems must determine log inactivation for Giardia lamblia through the
entire plant, based on CT99.9 values in Tables 1.1 through
1.6, 2.1 and 3.1 of Sec. 141.74(b) as applicable. Systems must
determine log inactivation for viruses through the entire treatment
plant based on a protocol approved by the State.
(b) Systems with a single point of disinfectant application prior
to the entrance to the distribution system must conduct the monitoring
in paragraphs (b)(1) through (4) of this section. Systems with more
than one point of disinfectant application must conduct the monitoring
in paragraphs (b)(1) through (4) of this section for each disinfection
segment. Systems must monitor the parameters necessary to determine the
total inactivation ratio, using analytical methods in Sec. 141.74(a).
(1) For systems using a disinfectant other than UV, the temperature
of the disinfected water must be measured at each residual disinfectant
concentration sampling point during peak hourly flow or at an
alternative location approved by the State.
(2) For systems using chlorine, the pH of the disinfected water
must be measured at each chlorine residual disinfectant concentration
sampling point during peak hourly flow or at an alternative location
approved by the State.
(3) The disinfectant contact time(s) (T) must be determined during
peak hourly flow.
(4) The residual disinfectant concentration(s) (C) of the water
before or at the first customer and prior to each additional point of
disinfection must be measured during peak hourly flow.
(c) In lieu of conducting new monitoring under paragraph (b) of
this section, systems may elect to meet the requirements of paragrphs
(c)(1) or (2) of this section.
(1) Systems that have at least 12 consecutive months of existing
operational data that are substantially equivalent to data collected
under the provisions of paragraph (b) of this section may use these
data to develop disinfection profiles as specified in this section if
the system has neither made a significant change to its treatment
practice nor changed sources since the data were collected. Systems
using existing operational data may develop disinfection profiles for a
period of up to three years.
(2) Systems may use disinfection profile(s) developed under Sec.
141.172 or Sec. Sec. 141.530 through 141.536 in lieu of developing a
new profile if the system has neither made a significant change to its
treatment practice nor changed sources since the profile was developed.
Systems that have not developed a virus profile under Sec. 141.172 or
Sec. Sec. 141.530 through 141.536 must develop a virus profile using
the same monitoring data on which the Giardia lamblia profile is based.
(d) Systems must calculate the total inactivation ratio for Giardia
lamblia as specified in paragraphs (d)(1) through (3) of this section.
(1) Systems using only one point of disinfectant application may
determine the total inactivation ratio for the disinfection segment
based on either of the methods in paragraph (d)(1)(i) or (ii) of this
section.
(i) Determine one inactivation ratio (CTcalc/CT99.9)
before or at the first customer during peak hourly flow.
(ii) Determine successive CTcalc/CT99.9 values,
representing sequential inactivation ratios, between the point of
disinfectant application and a point before or at the first customer
during peak hourly flow. The system must calculate the total
inactivation ratio by determining (CTcalc/CT99.9) for each
sequence and then adding the (CTcalc/CT99.9) values together
to determine ([Sigma] (CTcalc/CT99.9)).
(2) Systems using more than one point of disinfectant application
before the first customer must determine the CT value of each
disinfection segment immediately prior to the next point of

[[Page 47783]]

disinfectant application, or for the final segment, before or at the
first customer, during peak hourly flow. The (CTcalc/CT99.9)
value of each segment and ([Sigma](CTcalc/CT99.9)) must be
calculated using the method in paragraph (d)(1)(ii) of this section.
(3) The system must determine the total logs of inactivation by
multiplying the value calculated in paragraph (d)(1) or (d)(2) of this
section by 3.0.
(4) Systems must calculate the log of inactivation for viruses
using a protocol approved by the State.
(5) Systems must retain the disinfection profile data in graphic
form, as a spreadsheet, or in some other format acceptable to the State
for review as part of sanitary surveys conducted by the State.

Sec. 141.714 Requirements when making a significant change in
disinfection practice.

(a) A system that is required to develop a disinfection profile
under the provisions of this subpart and that plans to make a
significant change to its disinfection practice must calculate a
disinfection benchmark and must notify the State prior to making such a
change. Significant changes to disinfection practice are defined in
paragraphs (a)(1) through (4) of this section.
(1) Changes to the point of disinfection;
(2) Changes to the disinfectant(s) used in the treatment plant;
(3) Changes to the disinfection process; and
(4) Any other modification identified by the State.
(5) Systems must use the procedures specified in paragraphs
(a)(5)(i) and (ii) of this section to calculate a disinfection
benchmark.
(i) For the year of profiling data collected and calculated under
Sec. 141.713, or for each year with profiles covering more than one
year, systems must determine the lowest mean monthly level of both
Giardia lamblia and virus inactivation. Systems must determine the mean
Giardia lamblia and virus inactivation for each calendar month for each
year of profiling data by dividing the sum of daily or weekly Giardia
lamblia and virus log inactivation by the number of values calculated
for that month.
(ii) The disinfection benchmark is the lowest monthly mean value
(for systems with one year of profiling data) or the mean of the lowest
monthly mean values (for systems with more than one year of profiling
data) of Giardia lamblia and virus log inactivation in each year of
profiling data.
(6) Systems must submit the information in paragraphs (a)(6)(i)
through (iii) of this section when notifying the State that they are
planning to make a significant change in disinfection practice.
(i) A description of the proposed change.
(ii) The disinfection profile and benchmark for Giardia lamblia and
viruses determined under Sec. Sec. 141.713 and 141.714.
(iii) An analysis of how the proposed change will affect the
current level of disinfection.

Treatment Technique Requirements

Sec. 141.720 Treatment requirements for filtered systems.

(a) Filtered systems or systems that are unfiltered and required to
install filtration must provide the level of treatment for
Cryptosporidium specified in this paragraph, based on their bin
classification as determined under Sec. 141.709 and their existing
treatment:

----------------------------------------------------------------------------------------------------------------
And the system uses the following filtration treatment in full compliance with
subpart H, P, and T of this section (as applicable), then the additional
treatment requirements are . . .
-------------------------------------------------------------------------------
If the system bin classification Conventional
is . . . filtration Slow sand or Alternative
treatment Direct filtration diatomaceous earth filtration
(including filtration technologies
softening)
----------------------------------------------------------------------------------------------------------------
(1) Bin 1....................... No additional No additional No additional No additional
treatment. treatment. treatment. treatment
(2) Bin 2....................... 1 log treatment... 1.5 log treatment. 1 log treatment... (\1\)
(3) Bin 3....................... 2 log treatment... 2.5 log treatment. 2 log treatment... (\2\)
(4) Bin 4....................... 2.5 log treatment. 3 log treatment... 2.5 log treatment. (\3\)
----------------------------------------------------------------------------------------------------------------
\1\ As determined by the State such that the total Cryptosporidium removal and inactivation is at least 4.0 log.

\2\ As determined by the State such that the total Cryptosporidium removal and inactivation is at least 5.0 log.

\3\ As determined by the State such that the total Cryptosporidium removal and inactivation is at least 5.5 log.

(b) Filtered systems must use one, or a combination, of the
management and treatment options listed in Sec. 141.722, termed the
microbial toolbox, to meet the additional Cryptosporidium treatment
requirements identified for each bin in paragraph (a) of this section.
(c) Systems classified in Bin 3 and Bin 4 must achieve at least 1
log of the additional treatment required under paragraph (a) of this
section using either one or a combination of the following: bag
filters, bank filtration, cartridge filters, chlorine dioxide,
membranes, ozone, and/or UV as specified in Sec. 141.722.

Sec. 141.721 Treatment requirements for unfiltered systems.

(a) Following completion of the initial source water monitoring
required under Sec. 141.702(a), unfiltered systems that meet all
filtration avoidance criteria of Sec. 141.71 must calculate the
arithmetic mean of all Cryptosporidium sample concentrations reported
under Sec. 141.702(a), along with any previously collected data that
satisfy the requirements of Sec. 141.708, and must meet the treatment
requirements in paragraph (b)(1) or (2) of this section, as applicable,
based on this concentration.
(b)(1) Unfiltered systems with a mean Cryptosporidium concentration
of 0.01 oocysts/L or less must provide at least 2 log Cryptosporidium
inactivation.
(2) Unfiltered systems with a mean Cryptosporidium concentration of
greater than 0.01 oocysts/L must provide at least 3 log Cryptosporidium
inactivation.
(c) Unfiltered systems must use chlorine dioxide, ozone, or UV as
specified in Sec. 141.722 to meet the Cryptosporidium inactivation
requirements of this section.
(1) Unfiltered systems that use chlorine dioxide or ozone and fail
to achieve the Cryptosporidium log inactivation required in paragraph
(b)(1) or (2) of this section, as applicable, on more than one day in
the calendar month are in violation of the treatment technique
requirement.
(2) Unfiltered systems that use UV light and fail to achieve the
Cryptosporidium log inactivation required in paragraph (b)(1) or (2) of
this section, as applicable, in at least 95% of the water that is
delivered to the public during each calendar month, based on monitoring
required under paragraph Sec. 141.729(d)(4), are in violation of the
treatment technique requirement.
(d) Unfiltered systems must meet the combined Cryptosporidium,
Giardia

[[Page 47784]]

lamblia, and virus inactivation requirements of this section and Sec.
141.72(a) using a minimum of two disinfectants, and each disinfectant
must separately achieve the total inactivation required for either
Cryptosporidium, Giardia lamblia, or viruses.
(e) Following completion of the second round of source water
monitoring required under Sec. 141.702(d), unfiltered systems that
meet all filtration avoidance criteria of Sec. 141.71 must calculate
the arithmetic mean of all Cryptosporidium sample concentrations
reported under Sec. 141.702(d) and must meet the treatment
requirements in paragraph (b)(1) or (2) of this section, as applicable,
based on this concentration.
(f) Any unfiltered system that meets all filtration avoidance
criteria of Sec. 141.71 and fails to complete the monitoring
requirements of Sec. Sec. 141.701 through 141.707 or choses not to
monitor pursuant to Sec. 141.701(g) must meet the treatment
requirements of paragraph (b)(2) of this section by the date applicable
under Sec. 141.701(e).

Sec. 141.722 Microbial toolbox options for meeting Cryptosporidium
treatment requirements.

(a) To meet the additional Cryptosporidium treatment requirements
of Sec. Sec. 141.720 and 141.721, systems must use microbial toolbox
options listed in this follwing table that are designed, implemented,
and operated in accordance with the requirements of this subpart.

Microbial Toolbox: Options, Credits and Criteria
------------------------------------------------------------------------
Proposed Cryptosporidium treatment
Toolbox option credit with design and
implementation criteria
------------------------------------------------------------------------
Source Toolbox Components
------------------------------------------------------------------------
(1) Watershed control program..... 0.5 log credit for State approved
program comprising EPA specified
elements. Specific criteria are in
Sec. 141.725(a).
(2) Alternative source/intake Bin classification based on
management. concurrent Cryptosporidium
monitoring. No presumptive credit.
Specific criteria are in Sec.
141.725(b).
-----------------------------------
Pre-Filtration Toolbox Components
------------------------------------------------------------------------
(3) Presedimentation basin with 0.5 log credit for new basins with
coagulation. continuous operation and coagulant
addition. No presumptive credit for
basins existing when monitoring is
required under Sec. 141.702.
Specific criteria are in Sec.
141.726(a).
(4) Two-stage lime softening...... 0.5 log credit for two-stage
softening with coagulant addition.
Specific criteria are in Sec.
141.726(b).
(5) Bank filtration............... 0.5 log credit for 25 foot setback;
1.0 log credit for 50 foot setback.
No presumptive credit for bank
filtration existing when monitoring
is required under Sec.
141.704(d)(1). Specific criteria
are in Sec. 141.726(c).
-----------------------------------
Treatment Performance Toolbox Components
------------------------------------------------------------------------
(6) Combined filter performance... 0.5 log credit for combined filter
effluent turbidity <= 0.15 NTU in
95% of samples each month. Specific
criteria are in Sec. 141.727(a).
(7) Individual filter performance. 1.0 log credit for individual filter
effluent turbidity <=0.1 NTU in 95%
of daily maximum samples each month
and no filter 0.3 NTU in
two consecutive measurements.
Specific criteria are in Sec.
141.727(b).
(8) Demonstration of performance.. Credit based on a demonstration to
the State through State approved
protocol. Specific criteria are in
Sec. 141.727(c).
-----------------------------------
Additional Filtration Toolbox Components
------------------------------------------------------------------------
(9) Bag filters................... 1 log credit with demonstration of
at least 2 log removal efficiency
in challenge test; Specific
criteria are in Sec. 141.728(a).
(10) Cartridge filters............ 2 log credit with demonstration of
at least 3 log removal efficiency
in challenge test; Specific
criteria are in Sec. 141.728(a).
(11) Membrane filtration.......... Log removal credit up to the lower
value of the removal efficiency
demonstrated during the challenge
test or verified by the direct
integrity test applied to the
system. Specific criteria are in
Sec. 141.728(b).
(12) Second stage filtration...... 0.5 log credit for a second separate
filtration stage in treatment
process following coagulation.
Specific criteria are in Sec.
141.728(c).
(13) Slow sand filers............. 2.5 log credit for second separate
filtration process. Specific
criteria are in Sec. 141.728(d).
-----------------------------------
Inactivation Toolbox Components
------------------------------------------------------------------------
(14) Chlorine dioxide............. Log credit based on demonstration of
compliance with CT table. Specific
criteria are in Sec. 141.729(b).
(15) Ozone........................ Log credit based on demonstration of
compliance with CT table. Specific
criteria are in Sec. 141.729(c).
(16) UV........................... Log credit based on demonstration of
compliance with UV dose table.
Specific criteria are in Sec.
141.729(d).
------------------------------------------------------------------------

(b) Failure to comply with the requirements of this section in
accordance with the schedule in Sec. 141.701(e) is a treatment
technique violation.

Sec. 141.723 [Reserved]

Sec. 141.724 Requirements for uncovered finished water storage
facilities.

(a) Systems using uncovered finished water storage facilities must
comply with the conditions of one of the paragraphs (a)(1) through (3)
of this section for each facility no later than the date specified in
Sec. 141.701(h).
(1) Systems must cover any uncovered finished water storage
facility.
(2) Systems must treat the discharge from the uncovered finished
water storage facility to the distribution system to achieve at least 4
log virus inactivation using a protocol approved by the State.
(3) Systems must have a State-approved risk mitigation plan for the
uncovered finished water storage facility that addresses physical
access and site security, surface water runoff, animal and bird waste,
and ongoing water quality assessment, and includes a schedule for plan
implementation. Systems must implement the risk

[[Page 47785]]

mitigation plan approved by the State. Systems must submit risk
mitigation plans to the State for approval no later than [Date 24
Months After Date of Publication of Final Rule in the Federal
Register].
(b) Failure to comply with the requirements of this section in
accordance with the schedule in Sec. 141.701(h) is a treatment
technique violation.

Requirements for Microbial Toolbox Components

Sec. 141.725 Source toolbox components.

(a) Watershed control program.
(1) Systems that intend to qualify for a 0.5 log credit for
Cryptosporidium removal for a watershed control program must notify the
State no later than one year after completing the source water
monitoring requirements of Sec. 141.702(b) that they intend to develop
a watershed control program and to submit it for State approval.
(2) Systems must submit a proposed initial watershed control plan
and a request for plan approval and 0.5 log Cryptosporidium removal
credit to the State no later than two years after completing the source
water monitoring requirements of Sec. 141.702(b). Based on a review of
the initial proposed watershed control plan, the State may approve,
reject, or conditionally approve the plan. If the plan is approved, or
if the system agrees to implement the State's conditions for approval,
the system is awarded a 0.5 log credit for Cryptosporidium removal to
apply against additional treatment requirements.
(3) The application to the State for initial program approval must
include elements in paragraphs (a)(3)(i) through (iii) of this section.
(i) An analysis of the vulnerability of each source to
Cryptosporidium. The vulnerability analysis must address the watershed
upstream of the drinking water intake and must include the following: a
characterization of the watershed hydrology, identification of an
``area of influence'' (the area to be considered in future watershed
surveys) outside of which there is no significant probability of
Cryptosporidium or fecal contamination affecting the drinking water
intake, identification of both potential and actual sources of
Cryptosporidium contamination, the relative impact of the sources of
Cryptosporidium contamination on the system's source water quality, and
an estimate of the seasonal variability of such contamination.
(ii) An analysis of control measures that could mitigate the
sources of Cryptosporidium contamination identified during the
vulnerability analysis. The analysis of control measures must address
their relative effectiveness in reducing Cryptosporidium loading to the
source water and their feasability and sustainability.
(iii) A plan that establishes goals and defines and prioritizes
specific actions to reduce source water Cryptosporidium levels. The
plan must explain how the actions are expected to contribute to
specific goals, identify watershed partners and their role(s), identify
resource requirements and commitments, and include a schedule for plan
implementation.
(4) Initial State approval of a watershed control plan and its
associated 0.5 log Cryptosporidium removal credit is valid until the
system completes the second round of Cryptosporidium monitoring
required under Sec. 141.702(d). Systems must complete the actions in
paragraphs (a)(4)(i) through (iv) of this section to maintain State
approval and the 0.5 log credit.
(i) Submit an annual watershed control program status report to the
State by a date determined by the State. The annual watershed control
program status report must describe the system's implementation of the
approved plan and assess the adequacy of the plan to meet its goals. It
must explain how the system is addressing any shortcomings in plan
implementation, including those previously identified by the State or
as the result of the watershed survey conducted under paragraph
(a)(4)(ii) of this section. If it becomes necessary during
implementation to make substantial changes in its approved watershed
control program, the system must notify the State and provide a
rationale prior to making any such changes. If any change is likely to
reduce the level of source water protection, the system must also
include the actions it will take to mitigate the effects in its
notification.
(ii) Conduct an annual watershed sanitary survey and submit the
survey report to the State for approval. The survey must be conducted
according to State guidelines and by persons approved by the State to
conduct watershed surveys. The survey must encompass the area of the
watershed that was identified in the State-approved watershed control
plan as the area of influence and, at a minimum, assess the priority
activities identified in the plan and identify any significant new
sources of Cryptosporidium.
(iii) Submit to the State a request for review and re-approval of
the watershed control program and for a continuation of the 0.5 log
removal credit for a subsequent approval period. The request must be
provided to the State at least six months before the current approval
period expires or by a date previously determined by the State. The
request must include a summary of activities and issues identified
during the previous approval period and a revised plan that addresses
activities for the next approval period, including any new actual or
potential sources of Cryptosporidium contamination and details of any
proposed or expected changes from the existing State-approved program.
The plan must address goals, prioritize specific actions to reduce
source water Cryptosporidium, explain how actions are expected to
contribute to achieving goals, identify partners and their role(s),
resource requirements and commitments, and the schedule for plan
implementation.
(iv) The annual status reports, watershed control plan and annual
watershed sanitary surveys must be made available to the public upon
request. These documents must be in a plain language style and include
criteria by which to evaluate the success of the program in achieving
plan goals. If approved by the State, the system may withhold portions
of the annual status report, watershed control plan, and watershed
sanitary survey based on security considerations.
(5) Unfiltered systems may not claim credit for Cryptosporidium
removal under this option.
(b) Alternative source. (1) If approved by the State, a system may
be classified in a bin under Sec. 141.709 based on monitoring that is
conducted concurrently with source water monitoring under Sec. 141.701
and reflects a different intake location (either in the same source or
for an alternate source) or a different procedure for managing the
timing or level of withdrawal from the source.
(2) Sampling and analysis of Cryptosporidium in the concurrent
round of monitoring must conform to the requirements for monitoring
conducted under this subpart to determine bin classification. Systems
must submit the results of all monitoring to the State, along with
supporting information documenting the operating conditions under which
the samples were collected.
(3) If the State classifies the system in a bin based on monitoring
that reflects a different intake location or a different procedure for
managing the timing or level of withdrawal from the source, the system
must relocate the intake or use

[[Page 47786]]

the intake management strategy, as applicable, no later than the
applicable date for treatment technique implementation in Sec.
141.701. The State may specify reporting requirements to verify
operational practices.

Sec. 141.726 Pre-filtration treatment toolbox components.

(a) Presedimentation. New presedimentation basins that meet the
criteria in paragraphs (a)(1) through (4) of this section are eligible
for 0.5 log Cryptosporidium removal credit. Systems with
presedimentation basins existing when the system is required to conduct
monitoring under Sec. 141.702(a) may not claim this credit and, during
periods when the basins are in use, must collect samples after the
basins for the purpose of determining bin classification under Sec.
141.709.
(1) The presedimentation basin must be in continuous operation and
must treat all of the flow reaching the treatment plant.
(2) The system must continuously add a coagulant to the
presedimentation basin.
(3) Presedimentation basin influent and effluent turbidity must be
measured at least once per day or more frequently as determined by the
State.
(4) The system must demonstrate on a monthly basis at least 0.5 log
reduction of influent turbidity through the presedimentation process in
at least 11 of the 12 previous consecutive months.
(i) The monthly demonstration of turbidity reduction must be based
on the mean of daily turbidity readings collected under paragraph
(a)(3) of this section and calculated as follows:
log10(monthly mean of daily influent turbidity)--
log10(monthly mean of daily effluent turbidity).
(ii) If the presedimentation process has not been in operation for
12 months, the system must verify on a monthly basis at least 0.5 log
reduction of influent turbidity through the presedimentation process,
calculated as specified in this paragraph, for at least all but any one
of the months of operation.
(b) Two-stage lime softening. Systems that operate a two-stage lime
softening plant are eligible for an additional 0.5 log Cryptosporidium
removal credit if there is a second clarification step between the
primary clarifier and filter(s) that is operated continuously. Both
clarifiers must treat all of the plant flow and a coagulant, which may
be excess lime or magnesium hydroxide, must be present in both
clarifiers.
(c) Bank filtration. New bank filtration that serves as
pretreatment to a filtration plant is eligible for either a 0.5 or a
1.0 log Cryptosporidium removal credit towards the requirements of this
subpart if it meets the design criteria specified in paragraphs (c)(1)
through (c)(5) of this section and the monitoring and reporting
criteria of paragraph (c)(6) of this section. Wells with a ground water
flow path of at least 25 feet are eligible for 0.5 log removal credit;
wells with a ground water flow path of at least 50 feet are eligible
for 1.0 log removal credit. The ground water flow path must be
determined as specified in paragraph (c)(5) of this section.
(1) Only horizontal and vertical wells are eligible for bank
filtration removal credit.
(2) Only wells in granular aquifers are eligible for bank
filtration removal credit. Granular aquifers are those comprised of
sand, clay, silt, rock fragments, pebbles or larger particles, and
minor cement. The aquifer material must be unconsolidated as
demonstrated by the aquifer characterization specified in paragraph
(c)(3) of this section, unless the system meets the conditions of
paragraph (c)(4) of this section. Wells located in consolidated
aquifers, fractured bedrock, karst limestone, and gravel aquifers are
not eligible for bank filtration removal credit.
(3) A system seeking removal credit for bank filtration must
characterize the aquifer at the well site to determine aquifer
properties. The aquifer characterization must include the collection of
relatively undisturbed continuous core samples from the surface to a
depth at least equal to the bottom of the well screen. The recovered
core length must be at least 90 percent of the total projected depth to
the well screen, and each sampled interval must be a composite of no
more than 2 feet in length. A well is eligible for removal credit if at
least 90 percent of the composited intervals from the aquifer contain
at least 10 percent fine grained material, which is defined as grains
less than 1.0 mm in diameter.
(4) Wells constructed in partially consolidated granular aquifers
are eligible for removal credit if approved by the State based on a
demonstraton by the system that the aquifer provides sufficient natural
filtration. The demonstration must include a characterization of the
extent of cementation and fractures present in the aquifer.
(5) For vertical wells, the ground water flow path is the measured
horizontal distance from the edge of the surface water body to the
well. This horzontal distance to the surface water must be determined
using the floodway boundary or 100 year flood elevation boundary as
delineated on Federal Emergency Management Agency (FEMA) Flood
Insurance Rate maps. If the floodway boundary or 100 year flood
elevation boundary is not delineated, systems must determine the
floodway or 100 year flood elevation boundary using methods
substantially equilvalent to those used in preparing FEMA Flood
Insurance Rate maps. For horizontal wells, the ground water flow path
is the closest measured distance from the bed of the river under normal
flow conditions to the closest horizontal well lateral intake.
(6) Turbidity measurements must be performed on representative
samples from each wellhead at least every four hours that the bank
filtration is in operation. Continuous turbidity monitoring at each
wellhead may be used if the system validates the continuous measurement
for accuracy on a regular basis using a protocol approved by the State.
If the monthly average of daily maximum turbidity values at any well
exceeds 1 NTU, the system must report this finding to the State within
30 days. In addition, within 30 days of the exceedance, the system must
conduct an assessment to determine the cause of the high turbidity
levels and submit that assessment to the State for a determination of
whether any previously allowed credit is still appropriate.
(7) Systems with bank filtration that serves as pretreatment to a
filtration plant and that exists when the system is required to conduct
monitoring under Sec. 141.702(a) may not claim this credit. During
periods when the bank filtration is in use, systems must collect
samples after the bank filtration for the purpose of determining bin
classification under Sec. 141.709.

Sec. 141.727 Treatment performance toolbox components.

(a) Combined filter performance. Systems using conventional
filtration treatment or direct filtration treatment may claim an
additional 0.5 log Cryptosporidium removal credit for any month at each
plant that demonstrates that combined filter effluent (CFE) turbidity
levels are less than or equal to 0.15 NTU in at least 95 percent of the
measurements taken each month, based on sample measurements collected
under Sec. Sec. 141.73,141.173(a) and 141.551. Systems may not claim
credit under this paragraph and paragraph (b) in the same month.
(b) Individual filter performance. Systems using conventional
filtration treatment or direct filtration treatment

[[Page 47787]]

may claim an additional 1.0 log Cryptosporidium removal credit for any
month at each plant that meets both the individual filter effluent
(IFE) turbidity requirements of paragraphs (b)(1) and (2) of this
section, based on monitoring conducted under Sec. Sec. 141.174(a) and
141.560.
(1) IFE turbidity must be less than 0.1 NTU in at least 95% of the
maximum daily values recorded at each filter in each month, excluding
the 15 minute period following return to service from a filter
backwash.
(2) No individual filter may have a measured turbidity greater than
0.3 NTU in two consecutive measurements taken 15 minutes apart.
(c)(1) Demonstration of performance. Systems may demonstrate to the
State, through the use of State-approved protocols, that a plant, or
unit process of a plant, achieves a mean Cryptosporidium removal
efficiency greater than any presumptive credit specified under Sec.
141.720 or Sec. Sec. 141.725 through 141.728. Systems are eligible
for an increased Cryptosporidium removal credit if the State determines
that the plant or process can reliably achieve such a removal
efficiency on a continuing basis and the State provides written
notification of its determination to the system. States may establish
ongoing monitoring and/or performance requirements the State determines
are necessary to demonstrate the greater credit and may require the
system to report operational data on a monthly basis to verify that
conditions under which the demonstration of performance was awarded are
maintained during routine operations. If the State determines that a
plant, or unit process of a plant, achieves an average Cryptosporidium
removal efficiency less than any presumptive credit specified under
Sec. 141.720 or Sec. Sec. 141.725 through 141.728, the State may
assign the lower credit to the plant or unit process.
(2) Systems may not claim presumptive credit for any toolbox box
component in Sec. Sec. 141.726, 141.727(a) and (b), or 141.728 if
that component is also included in the demonstration of performance
credit.

Sec. 141.728 Additional filtration toolbox components.

(a) Bag and cartridge filters. Systems are eligible for a 1 log
Cryptosporidium removal credit for bag filters and a 2 log
Cryptosporidium removal credit for cartridge filters by meeting the
criteria in paragraphs (a)(1) through (a)(10) of this section. The
request to the State for this credit must include the results of
challenge testing that meets the requirements of paragraphs (a)(2)
through (a)(9) of this section.
(1) To receive a 1 log Cryptosporidium removal credit for a bag
filter, the filter must demonstrate a removal efficiency of 2 log or
greater for Cryptosporidium. To receive a 2 log Cryptosporidium removal
credit for a cartridge filter, the filter must demonstrate a removal
efficiency of 3 log or greater for Cryptosporidium. Removal efficiency
must be demonstrated through challenge testing conducted according to
the criteria in paragraphs (a)(2) through (a)(9) of this section. The
State may accept data from challenge testing conducted prior to [Date
of Publication of Final Rule in the Federal Register] in lieu of
additional testing if the prior testing was consistent with the
criteria specified in paragraphs (a)(2) through (a)(9) of this section.
(2) Challenge testing must be performed on full-scale bag or
cartridge filters that are identical in material and construction to
the filters proposed for use in full-scale treatment facilities for
removal of Cryptosporidium.
(3) Challenge testing must be conducted using Cryptosporidium
oocysts or a surrogate that is removed no more efficiently than
Cryptosporidium oocysts. The organism or surrogate used during
challenge testing is referred to as the challenge particulate. The
concentration of the challenge particulate must be determined using a
method capable of discreetly quantifying the specific organism or
surrogate used in the test; gross measurements such as turbidity may
not be used.
(4) The maximum feed water concentration that can be used during a
challenge test must be based on the detection limit of the challenge
particulate in the filtrate (i.e., filtrate detection limit) and must
be calculated using the equation in either paragraph (a)(4)(i) or
(a)(4)(ii) of this section as applicable.
(i) For cartridge filters: Maximum Feed Concentration = 3.16x10\4\
x (Filtrate Detection Limit).
(ii) For bag filters: Maximum Feed Concentration = 3.16x10\3\ x
(Filtrate Detection Limit).
(5) Challenge testing must be conducted at the maximum design flow
rate for the filter as specified by the manufacturer.
(6) Each filter evaluated must be tested for a duration sufficient
to reach 100 percent of the terminal pressure drop, which establishes
the maximum pressure drop under which the filter may be used to comply
with the requirements of this subpart.
(7) Each filter evaluated must be challenged with the challenge
particulate during three periods over the filtration cycle: within two
hours of start-up after a new bag or cartridge filter has been
installed; when the pressure drop is between 45 and 55 percent of the
terminal pressure drop; and at the end of the run after the pressure
drop has reached 100 percent of the terminal pressure drop.
(8) Removal efficiency of a bag or cartridge filter must be
determined from the results of the challenge test and expressed in
terms of log removal values using the following equation:

LRV = LOG10(Cf)-LOG10(Cp)

[[Page 47788]]

membrane filtration process under the conditions in paragraph (b)(3) of
this section.
(2) Challenge Testing. The membrane used by the system must undergo
challenge testing to evaluate removal efficiency, and the system must
submit the results of challenge testing to the State. Challenge testing
must be conducted according to the criteria in paragraphs (b)(2)(i)
through (b)(2)(vii) of this section. The State may accept data from
challenge testing conducted prior to [Date of Publication of Final Rule
in the Federal Register] in lieu of additional testing if the prior
testing was consistent with the criteria in paragraphs (b)(2)(i)
through (b)(2) (vii) of this section.
(i) Challenge testing must be conducted on either a full-scale
membrane module, identical in material and construction to the membrane
modules used in the system's treatment facility, or a smaller-scale
membrane module, identical in material and similar in construction to
the full-scale module.
(ii) Challenge testing must be conducted using Cryptosporidium
oocysts or a surrogate that is removed no more efficiently than
Cryptosporidium oocysts. The organism or surrogate used during
challenge testing is referred to as the challenge particulate. The
concentration of the challenge particulate must be determined using a
method capable of discretely quantifying the specific challenge
particulate used in the test; gross measurements such as turbidity may
not be used.
(iii) The maximum feed water concentration that can be used during
a challenge test is based on the detection limit of the challenge
particulate in the filtrate and must be determined according to the
following equation:

Maximum Feed Concentration = 3.16x10\6\ x (Filtrate Detection Limit)

(iv) Challenge testing must be conducted under representative
hydraulic conditions at the maximum design flux and maximum design
process recovery specified by the manufacture for the membrane module.
Flux is defined as the rate of flow per unit of membrane area. Recovery
is defined as the ratio of filtrate volume produced by a membrane to
feed water volume applied to a membrane over the course of an
uninterrupted operating cycle. An operating cycle is bounded by two
consecutive backwash or cleaning events. For the purpose of challenge
testing in this section, recovery does not consider losses that occur
due to the use of filtrate in backwashing or cleaning operations.
(v) Removal efficiency of a membrane module during challenge
testing must be determined as a log removal using the following
equation:

LRV = LOG10(Cf) - LOG10(Cp)

LRVDIT = LOG10(Qp /(VCF x
Qbreach))

where LRVDIT = maximum log removal value that can be
verified by a direct integrity test; Qp = total design
filtrate flow from the membrane unit; Qbreach = flow of
water from an integrity breach associated with the smallest integrity
test response that can be reliably measured, and VCF = volumetric
concentration factor. The volumetric concentration factor is the ratio
of the suspended solids concentration on the high pressure side of the
membrane relative to that in the feed water.
(B) For direct integrity tests that use a particulate or molecular
marker, the maximum log removal value that can be verified by the test
must be calculated according to the following equation:

LRVDIT = LOG10(Cf)-
LOG10(Cp)

where LRVDIT = maximum log removal value that can be
verified by a direct integrity test; Cf = the typical feed
concentration of the marker used in the test; and Cp = the
filtrate concentration of the marker from an integral membrane unit.
(iv) Systems must establish a control limit for the direct
integrity test that is indicative of an integral membrane unit capable
of meeting the removal credit awarded by the State.
(v) If the result of a direct integrity test is outside the control
limit established under paragraphs (b)(3)(i) through (b)(3)(iv) of this
section, the membrane unit must be removed from service. A direct
integrity test must be

[[Page 47789]]

conducted to verify any repairs, and the membrane unit may be returned
to service only if the direct integrity test is within the established
control limit.
(vi) Direct integrity testing must be conducted on each membrane
unit at a frequency of not less than once each day that the membrane
unit is in operation.
(4) Indirect integrity monitoring. Systems must conduct continuous
indirect integrity monitoring on each membrane unit according to the
criteria in paragraphs (b)(4)(i) through (b)(4)(v) of this section. A
system that implements continuous direct integrity testing of membrane
units in accordance with the criteria in paragraphs (b)(3)(i) through
(b)(3)(v) of this section is not subject to the requirements for
continuous indirect integrity monitoring.
(i) Unless the State approves an alternative parameter, continuous
indirect integrity monitoring must include continuous filtrate
turbidity monitoring.
(ii) Continuous monitoring must be conducted at a frequency of no
less than once every 15 minutes.
(iii) Continuous monitoring must be separately conducted on each
membrane unit.
(iv) If indirect integrity monitoring includes turbidity and if the
filtrate turbidity readings are above 0.15 NTU for a period greater
than 15 minutes (i.e., two consecutive 15-minute readings above 0.15
NTU), direct integrity testing must be performed on the associated
membrane units as specified in paragraphs (b)(3)(i) through (b)(3)(v)
of this section.
(v) If indirect integrity monitoring includes a State-approved
alternative parameter and if the alternative parameter exceeds a State-
approved control limit for a period greater than 15 minutes, direct
integrity testing must be performed on the associated membrane units as
specified in paragraphs (b)(3)(i) through (b)(3)(v) of this section.
(c) Second stage filtration. Systems are eligible for an additional
0.5 log Cryptosporidium removal credit if they have a separate second
stage filtration process consisting of rapid sand, dual media, GAC, or
other fine grain media in a separate stage following rapid sand or dual
media filtration. To be eligible for this credit, the first stage of
filtration must be preceded by a coagulation step and both filtration
stages must treat 100% of the flow. A cap, such as GAC, on a single
stage of filtration is not eligible for this credit.
(d) Slow sand filtration. Systems may claim a 2.5 log
Cryptosporidium removal credit for a slow sand filtration process that
follows another separate filtration process if all the flow is treated
by both processes and no disinfectant residual is present in the
influent water to the slow sand filtration process.

Sec. 141.729 Inactivation toolbox components.

(a) Calculation of CT values. (1) CT is the product of the
disinfectant contact time (T, in minutes) and disinfectant
concentration (C, in milligrams per liter). Systems must calculate CT
at least once each day, with both C and T measured during peak hourly
flow as specified in Sec. Sec. 141.74(a) and 141.74(b).
(2) Systems with several disinfection segments (a segment is
defined as a treatment unit process with a measurable disinfectant
residual level and a liquid volume) in sequence along the treatment
train, may calculate the CT for each disinfection segment and use the
sum of the Cryptosporidium log inactivation values achieved through the
plant.
(b) CT values for chlorine dioxide. (1) Systems using chlorine
dioxide must calculate CT in accordance with Sec. 141.729(a).
(2) Unless the State approves alternative CT values for a system
under paragraph (b)(3) of this section, systems must use the following
table to determine Cryptosporidium log inactivation credit:

CT Values for Cryptosporidium Inactivation by Chlorine Dioxide
--------------------------------------------------------------------------------------------------------------------------------------------------------
Water Temperature, [deg] C \1\
Log credit -------------------------------------------------------------------------------------------------------------
<=0.5 1 2 3 5 7 10 15 20 25
--------------------------------------------------------------------------------------------------------------------------------------------------------
0.5....................................... 319 305 279 256 214 180 138 89 58 38
1.0....................................... 637 610 558 511 429 360 277 179 116 75
1.5....................................... 956 915 838 767 643 539 415 268 174 113
2.0....................................... 1275 1220 1117 1023 858 719 553 357 232 150
2.5....................................... 1594 1525 1396 1278 1072 899 691 447 289 188
3.0....................................... 1912 1830 1675 1534 1286 1079 830 536 347 226
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CT values between the indicated temperatures may be determined by interpolation.

CT Values for Cryptosporidium Inactivation by Ozone
--------------------------------------------------------------------------------------------------------------------------------------------------------
Water Temperature, [deg]C1 \1\
Log credit -------------------------------------------------------------------------------------------------------------------
<=0.5 1 2 3 5 7 10 15 20 25
--------------------------------------------------------------------------------------------------------------------------------------------------------
0.5................................. 12 12 10 9.5 7.9 6.5 4.9 3.1 2.0 1.2
1.0................................. 24 23 21 19 16 13 9.9 6.2 3.9 2.5
1.5................................. 36 35 31 29 24 20 15 9.3 5.9 3.7
2.0................................. 48 46 42 38 32 26 20 12 7.8 4.9
2.5................................. 60 58 52 48 40 33 25 16 9.8 6.2

[[Page 47790]]

3.0................................. 72 69 63 57 47 39 30 19 12 7.4
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CT values between the indicated temperatures may be determined by interpolation

(3) Systems may conduct a site-specific inactivation study to
determine the CT values necessary to meet a specified Cryptosporidium
log inactivation level, using a State-approved protocol. The
alternative CT values determined from the site-specific study and the
method of calculation must be approved by the State.
(d) Ultraviolet light. (1) Systems may claim credit for ultraviolet
(UV) processes for inactivation of Cryptosporidium, Giardia lamblia,
and viruses. The allowable inactivation credit for each pathogen must
be based on the UV dose delivered by the system's UV reactors in
relation to the UV dose table in paragraph (d)(2) of this section.
(2) UV dose table. The log credits given in this UV dose table are
for UV light at a wavelength of 254 nm as produced by a low pressure
mercury vapor lamp. Systems may apply this table to UV reactors with
other lamp types through reactor validation testing (i.e., performance
demonstration) as described in paragraph (d)(3) of this section. The UV
dose values in this table are applicable only to post-filter
application of UV in systems that filter under subpart H of this part
and to unfiltered systems meeting the filtration avoidance criteria in
subparts H, P, and T of this part:

UV Dose Table for Cryptosporidium, Giardia Lamblia, and Virus Inactivation Credit
----------------------------------------------------------------------------------------------------------------
Cryptosporidium Giardia lamblia
Log credit UV Dose (mJ/cm UV dose (mJ/cm Virus UV dose
\2\) \2\) (mJ/cm \2\)
----------------------------------------------------------------------------------------------------------------
0.5........................................................... 1.6 1.5 39
1.0........................................................... 2.5 2.1 58
1.5........................................................... 3.9 3.0 79
2.0........................................................... 5.8 5.2 100
2.5........................................................... 8.5 7.7 121
3.0........................................................... 12 11 143
3.5........................................................... NA NA 163
4.0........................................................... NA NA 186
----------------------------------------------------------------------------------------------------------------

(3) Reactor validation testing. For a system to receive
inactivation credit for a UV reactor, the reactor must undergo the
validation testing in paragraphs (d)(3)(i) and (d)(3)(ii) of this
section, unless the State approves an alternative approach. The
validation testing must demonstrate the operating conditions under
which the reactor can deliver the UV dose required in paragraph (d)(2)
of this section.
(i) Validation testing of UV reactors must determine a range of
operating conditions that can be monitored by the system and under
which the reactor delivers the required UV dose. At a minimum, these
operating conditions must include flow rate, UV intensity as measured
by a UV sensor, and UV lamp status. The validated operating conditions
determined by this testing must account for the following: UV
absorbance of the water; lamp fouling and aging; measurement
uncertainty of on-line sensors; UV dose distributions arising from the
velocity profiles through the reactor; failure of UV lamps or other
critical system components; and inlet and outlet piping or channel
configurations of the UV reactor.
(ii) Validation testing must include the following: full scale
testing of a reactor that conforms uniformly to the UV reactors used by
the system; and inactivation of a test microorganism whose dose
response characteristics have been quantified with a low pressure
mercury vapor lamp.
(4) Reactor monitoring. Systems must monitor their UV reactors to
demonstrate that they are operating within the range of conditions that
were validated by the testing described in paragraphs (d)(3)(i) and
(d)(3)(ii) of this section to achieve the required UV dose in paragraph
(d)(2) of this section. Systems must monitor for UV intensity as
measured by a UV sensor, flow rate, and lamp outage and for any other
parameters required by the State. Systems must verify the calibration
of UV sensors and must recalibrate sensors in accordance with a
protocol approved by the State.

Reporting and Recordkeeping Requirements

Sec. 141.730 Reporting requirements.

(a) Systems must follow the requirements for reporting sampling
schedules under Sec. 141.703 and for reporting source water monitoring
results under Sec. 141.707 unless they notify the State that they will
not conduct source water monitoring due to meeting the criteria of
Sec. 141.701(f) or (g).
(b) Systems using uncovered finished water storage facilities must
notify the State of the use of each facility no later than [Date 24
Months After Date of Publication of Final Rule in the Federal
Register].
(c) Filtered systems and unfiltered systems that are required to
install filtration must report their Cryptosporidium bin
classification, as determined under using the procedures in Sec.
141.709, to the State by the applicable dates in paragraph (c)(1) or
(2) of this section.
(1) Systems that serve at least 10,000 people must report their
initial bin classification no later than [Date 36 Months After Date of
Publication of Final Rule in the Federal Register] and must report
their bin classification determined using results from the second round
of source water monitoring no later than [Date 138 Months After Date of
Publication of Final Rule in the Federal Register].

[[Page 47791]]

(2) Systems that serve fewer than 10,000 people must report their
initial bin classification no later than [Date 66 Months After Date of
Publication of Final Rule in the Federal Register] and must report
their bin classification determined using results from the second round
of source water monitoring no later than [Date 174 Months After Date of
Publication of Final Rule in the Federal Register].
(d) Unfiltered systems that meet all filtration avoidance criteria
of Sec. 141.71 must report their mean Cryptosporidium concentration,
as determined under Sec. 141.721, to the State by the applicable dates
in paragraph (d)(1) or (2) of this section.
(1) Systems that serve at least 10,000 people must report their
initial mean Cryptosporidium concentration no later than [Date 36
Months After Date of Publication of Final Rule in the Federal Register]
and must report their mean Cryptosporidium concentration determined
using results from the second round of source water monitoring no later
than [Date 138 Months After Date of Publication of Final Rule in the
Federal Register].
(2) Systems that serve fewer than 10,000 people must report their
initial mean Cryptosporidium concentration no later than [Date 66
Months After Date of Publication of Final Rule in the Federal Register]
and must report their mean Cryptosporidium concentration determined
using results from the second round of source water monitoring no later
than [Date 174 Months After Date of Publication of Final Rule in the
Federal Register].
(e) Systems must report to the State in accordance with the
following table in this paragraph for any toolbox options used to
comply with the Cryptosporidium treatment technique requirements under
Sec. 141.720 or Sec. 141.721. The State may place additional
reporting requirements it determines to be necessary to verify
operation in accordance with required criteria for all toolbox options:

Microbial Toolbox Reporting Requirements
----------------------------------------------------------------------------------------------------------------
On the following
Systems must submit schedule\1\ --systems On the following
Toolbox option the following serving = schedule\1\--systems
information 10,000 people serving < 10,000 people
----------------------------------------------------------------------------------------------------------------
(1) Watershed control program (WCP) (i) Notify State of No later than [Date 48 No later than [Date 78
intention to develop Months After Date of Months After Date of
WCP. Publication of Final Publication of Final Rule
Rule in the Federal in the Federal Register].
Register].
(ii) Submit initial No later than [Date 60 No later than [Date 90
WCP plan to State. Months After Date of Months After Date of
Publication of Final Publication of Final Rule
Rule in the Federal in the Federal Register].
Register].
(iii) Annual report By a date determined By a date determined by the
and State-approved by the State, every State, every 12 months,
watershed survey 12 months, beginning beginning on [Date 114
report. on [Date 84 Months Months After Date of
After Date of Publication of Final Rule
Publication of Final in the Federal Register].
Rule in the Federal
Register].
(iv) Request for re- Six months prior to Six months prior to the end
approval and report the end of the of the current approval
on the previous current approval period or by a date
approval period. period or by a date previously determined by
previously determined the State.
by the State.
(2) Bank filtration................ (i) Initial Initial demonstration Initial demonstration no
demonstration of the no later than [Date later than [Date 102
following: 72 Months after Date Months after Date of
unconsolidated, of Publication of Publication of Final Rule
predominantly sandy Final Rule in the in the Federal Register].
aquifer and setback Federal Register].
distance of at least
25 ft. (0.5 log
credit) or 50 ft.
(1.0 log credit).
(ii) If monthly Report within 30 days Report within 30 days
average of daily max following the month following the month in
turbidity is greater in which the which the monitoring was
than 1 NTU then monitoring was conducted, beginning on
system must report conducted, beginning [Date 102 Months After
result and submit an on [Date 72 Months Date of Publication of
assessment of the After Date of Final Rule in the Federal
cause. Publication of Final Register].
Rule in the Federal
Register].
(3) Presedimentation............... Monthly verification Monthly reporting Monthly reporting within 10
of the following; within 10 days days following the month
Continuous basin following the month in which the monitoring
operation; treatment in which the was conducted, beginning
of 100% of the flow; monitoring was on [Date 102 Months After
continuous addition conducted, beginning Date of Publication of
of a coagulant; and on [Date 72 Months Final Rule in the Federal
at least 0.5 log After Date of Register].
removal of influent Publication of Final
turbidity based on Rule in the Federal
the monthly mean of Register].
daily turbidity
readings for 11 of
the 12 previous
months.
(4) Two-sage lime softening........ Monthly verification Monthly reporting Monthly reporting within 10
of the following: within 10 days days following the month
Continuous operation following the month in which the monitoring
of a second in which the was conducted, beginning
clarification step monitoring was on [Date 102 Months After
between the primary conducted, beginning Date of Publication of
clarifier and filter; on [Date 72 Months Final Rule in the Federal
continuous presence After Date of Register].
of a coagulant in Publication of Final
both primary and Rule in the Federal
secondary clarifiers; Register].
and both clarifiers
treated 100% of the
plant flow.

[[Page 47792]]

(5) Combined filter performance.... Monthly verification Monthly reporting Monthly reporting within 10
of combined filter within 10 days days following the month
effluent (CFE) following the month in which the monitoring
turbidity levels less in which the was conducted, beginning
than or equal to 0.15 monitoring was on [Date 102 Months After
NTU in at least 95 conducted, beginning Date of Publication of
percent of the 4 hour on [Date 72 Months Final Rule in the Federal
CFE measurements After Date of Register].
taken each month. Publication of Final
Rule in the Federal
Register].
(6) Individual filter performance.. Monthly verification Monthly reporting Monthly reporting within 10
of the following: within 10 days days following the month
Individual filter following the month in which the monitoring
effluent (IFE) in which the was conducted, beginning
turbidity levels less monitoring was on [Date 102 Months After
than or equal to 0.1 conducted, beginning Date of Publication of
NTU in at least 95 on [Date 72 Months Final Rule in the Federal
percent of all daily After Date of Register].
maximum IFE Publication of Final
measurements taken Rule in the Federal
each month (excluding Register].
15 min period
following start-up
after backwash); and
no individual filter
greater than 0.3 NTU
in two consecutive
readings 15 minutes
apart.
(7) Membrane filtration............ (i) Results of No later than [Date 72 No later than [Date 102
verification testing Months After Date of Months After Date of
demonstrating the Publication of Final Publication of Final Rule
following: Removal Rule in the Federal in the Federal Register].
efficiency Register].
established through
challenge testing
that meets criteria
in this subpart; and
integrity testing and
associated baseline.
(ii) Monthly report Within 10 days Within 10 days following
summarizing all following the month the month in which
direct integrity in which monitoring monitoring was conducted,
tests above the was conducted, beginning [Date 102 Months
control limit and, if beginning [Date 72 After Date of Publication
applicable, any Months After Date of of Final Rule in the
indirect integrity Publication of Final Federal Register].
monitoring results Rule in the Federal
triggering direct Register].
integrity testing and
the corrective action
that was taken.
(8) Bag filters and cartridge (i) Demonstration that No later than [Date 72 No later than [Date 102
filters. the following Months After Date of Months After Date of
criteria are met: Publication of Final Publication of Final Rule
process meets the Rule in the Federal in the Federal Register].
definition of bag or Register].
cartridge filtration;
removal efficiency
established through
challenge testing
that meets criteria
in this subpart; and
challenge test shows
at least 2 log
removal for bag
filters and 3 log
removal for cartridge
filters.
(ii) Monthly Within 10 days Within 10 days following
verification that following the month the month in which
100% of flow was in which monitoring monitoring was conducted,
filtered. was conducted, beginning [Date 102 Months
beginning [Date 72 After Date of Publication
Months After Date of of Final Rule in the
Publication of Final Federal Register].
Rule in the Federal
Register].
(9) Second stage filtration........ Monthly verification Within 10 days Within 10 days following
that 100% of flow was following the month the month in which
filtered through both in which monitoring monitoring was conducted,
stages. was conducted, beginning [Date 102 Months
beginning [Date 72 After Date of Publication
Months After Date of of Final Rule in the
Publication of Final Federal Register].
Rule in the Federal
Register].
(10) Slow and filtration........... Monthly verification Within 10 days Within 10 days following
that 100% of flow was following the month the month in which
filtered. in which monitoring monitoring was conducted,
was conducted, beginning [Date 102 Months
beginning [Date 72 After Date of Publication
Months After Date of of Final Rule in the
Publication of Final Federal Register].
Rule in the Federal
Register].
(11) Chlorine dioxide.............. Summary of CT values Within 10 days Within 10 days following
for each day based on following the month the month in which
Table in Sec. in which monitoring monitoring was conducted,
141.729(b). was conducted, beginning [Date 102 Months
beginning [Date 72 After Date of Publication
Months After Date of of Final Rule in the
Publication of Final Federal Register].
Rule in the Federal
Register].

[[Page 47793]]

(12) Ozone......................... Summary of CT values Within 10 days Within 10 days following
for each day based on following the month the month in which
Table in Sec. in which monitoring monitoring was conducted,
141.729(c). was conducted, beginning [Date 102 Months
beginning [Date 72 After Date of Publication
Months After Date of of Final Rule in the
Publication of Final Federal Register].
Rule in the Federal
Register].
(13) UV............................ (i) Validation test No later than [Date 72 No later than [Date 102
results demonstrating Months After Date of Months After Date of
operating conditions Publication of Final Publication of Final Rule
that achieve required Rule in the Federal in the Federal Register].
UV dose. Register].
(ii) Monthly report Within 10 days Within 10 days following
summarizing the following the month the month in which
percentage of water in which monitoring monitoring was conducted,
entering the was conducted, beginning [Date 102 Months
distribution system beginning [Date 72 After Date of Publication
that was not treated Months After Date of of Final Rule in the
by UV reactors Publication of Final Federal Register].
operating within Rule in the Federal
validated conditions Register].
for the required dose
as specified in Sec.
141.729(d).
(14) Demonstration of performance.. (i) Results from No later than [Date 72 No later than [Date 102
testing following a Months After Date of Months After Date of
State approved Publication of Final Publication of Final Rule
protocol. Rule in the Federal in the Federal Register].
Register].
(ii) As required by Within 10 days Within 10 days following
the State, monthly following the month the month in which
verification of in which monitoring monitoring was conducted,
operation within was conducted, beginning [Date 102 Months
conditions of State beginning [Date 72 After Date of Publication
approval for Months After Date of of Final Rule in the
demonstration of Publication of Final Federal Register].
performance credit. Rule in the Federal
Register].
----------------------------------------------------------------------------------------------------------------
\1\ States may allow up to an additional two years to the date when the first submittal must be completed for
systems making capital improvements.

(f) Systems must report to the State the information associated
with disinfection profiling and benchmarking requirements of Sec. Sec.
141.711 to 141.714 in accordance with the tables in this paragraph.

Table 1.--Disinfection Profiling Reporting Requirements for Large Systems
[Serving =10,000 people]
----------------------------------------------------------------------------------------------------------------
Submit the following On the following
System type Benchmark component items schedule
----------------------------------------------------------------------------------------------------------------
(1) Systems required to conduct (i) Characterization of Giardia lamblia and No later than [Date 36
Cyrptosporidium monitoring. disinfection virus inactivation Months After Date of
practices. See Sec. profiles must be on Publication of Final
141.713. file for State review Rule in the Federal
during sanitary survey. Register].
(ii) State review of Inactivation profile Prior to significant
proposed significant and benchmark modification of
changes to determinations. disinfection practice.
disinfection practice.
See Sec. 141.714.
(2) Systems not required to conduct (i) Applicability...... None................... None.
Cryptosporidium monitoring \a\.
(ii) Characterization None................... None.
of Disinfection
Practices.
(iii) State Review of None................... None.
Proposed Changes to
Disinfection Practices.
----------------------------------------------------------------------------------------------------------------
\a\Systems that provide at least 5.5 log of Cryptosporidium treatment, consistent with a Bin 4 treatment
requirement, are not required to conduct Cryptosporidium monitoring.

Table 2.--Disinfection Profiling Reporting Requirements for Small Systems
[Serving < 10,000 people]
----------------------------------------------------------------------------------------------------------------
Submit the following On the following
System type Benchmark component items schedule
----------------------------------------------------------------------------------------------------------------
(1) Systems required to conduct (i) Characterization of Giardia lamblia and No later than [Date 66
Cryptosporidium monitoring. disinfection virus disinfection Months After Date of
practices. See Sec. profiles must be on Publication of Final
141.713. file for State review Rule in the Federal
during sanitary survey. Register].

[[Page 47794]]

(ii) State review of Disinfection profiles Prior to significant
proposed significant and benchmark modification of
changes to determinations. disinfection practice.
disinfection
practices. See Sec.
141.714.
(2) Systems not required to conduct (i) Determination of Report on TTHM and HAA5 No later than [Date 42
Cryptosporidium monitoring and that requirement to LRAA values from Months After Date of
exceed DBP triggers ^a,b,c. profile. See Sec. monitoring under Publication of Final
141.711(b). subpart L. Rule in the Federal
Register].
(ii) Characterization Giardia lambia and No later than [Date 54
of disinfection virus disinfection Months after Date of
practices. See Sec. profiles must be on Publication of Final
141.713. file for State review Rule in the Federal
during sanitary survey. Register].
(iii) State review of Disinfection profiles Prior to significant
proposed significant and benchmark modification of
changes to determinations. disinfection practice.
disinfection
practices. See Sec.
141.714.
(3) Systems not required to conduct (i) Determination of no Report on TTHM and HAA5 No later than [Date 42
Cryptosporidium monitoring and that requirement to LRAA values from Months After Date of
do not exceed DBP triggers \b,c\. profile. See Sec. monitoring under Publication of Final
141.711(b). subpart L. Rule in the Federal
Register].
(ii) Characterization None................... None.
of disinfection
practices. See Sec.
141.713.
(iii) State review of None................... None.
proposed significant
changes to
disinfection practice.
See Sec. 141.714.
----------------------------------------------------------------------------------------------------------------
\a\ Systems that provide at least 5.5 log of Cryptosporidium treatment, consistent with a Bin 4 treatment
requirement, are not required to conduct Cryptosporidium monitoring.
\b\ See Sec. 141.702(b) to determine if Cryptosporidium monitoring is required.
\c\ See Sec. 141.711(b) to determine if disinfection profiling is required based on TTHM or HAA5 LRAA.

Sec. 141.731 Recordkeeping requirements.

(a) Systems must keep results from monitoring required under Sec.
141.702 until 36 months after all source water monitoring required
under this section has been completed.
(b) Systems must keep a record of any notification to the State
that they will not conduct source water monitoring due to meeting the
criteria of Sec. 141.701(f) or (g).
(c) Systems required to develop disinfection profiles under Sec.
141.711 must keep disinfection profiles on file for State review during
sanitary surveys.

PART 142--NATIONAL PRIMARY DRINKING WATER REGULATIONS
IMPLEMENTATION

5. The authority citation for part 142 continues to read as
follows:

Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9 and 300j-11.

6. Section 142.14 is amended by adding paragraphs (a)(8) and (a)(9)
to read as follows:

Sec. 142.14 Records kept by States.

* * * * *
(a) * * *
(8) [Reserved]
(9) Any decisions made pursuant to the provisions of part 141,
subpart W of this chapter.
(i) Results of source water E. coli and Cryptosporidium monitoring.
(ii) Initial bin classification for each system that currently
provides filtration or that is unfiltered and required to install
filtration, along with any change in bin classification due to
watershed assessment during sanitary surveys or the second round of
source water monitoring.
(iii) A determination of whether each system that is unfiltered and
meets all the filtration avoidance criteria of Sec. 141.71 of this
chapter has a mean source water Cryptosporidium level above 0.01
oocysts/L, along with any changes in this determination due to the
second round of source water monitoring.
(iv) The treatment or control measures that systems use to meet
their Cryptosporidium treatment requirements under Sec. 141.720 or
Sec. 141.721 of this section.
(v) A list of systems required to cover or treat the effluent of an
uncovered finished water reservoir.
(vi) A list of systems for which the State has waived the
requirement to cover or treat the effluent of uncovered finished water
storage facilities and supporting documentation of the risk mitigation
plan.
* * * * *
7. Section 142.15 is amended by adding paragraph (c)(6) to read as
follows:

Sec. 142.15 Reports by States.

(c) * * *
(6) Subpart W. (i) The initial bin classification for each system
that currently provides filtration or that is unfiltered and required
to install filtration, along with any change in bin classification due
to watershed assessment during sanitary surveys or the second round of
source water monitoring.
(ii) A determination of whether each system that is unfiltered and
meets all the filtration avoidance criteria of Sec. 141.71 of this
chapter has a mean source water Cryptosporidium level above 0.01
oocysts/L, along with any changes in this determination due to the
second round of source water monitoring.
* * * * *
8. Section 142.16 is amended by adding paragraphs (m) and (n) to
read as follows:

Sec. 142.16 Special primacy conditions.

* * * * *
(m) [Reserved]
(n) Requirements for States to adopt 40 CFR part 141, subpart W. In
addition to the general primacy requirements elsewhere in this part,
including the requirements that State regulations be at least as
stringent as federal requirements, an application for approval of a
State program revision that adopts 40 CFR part 141, subpart W,

[[Page 47795]]

must contain a description of how the State will accomplish the
following program requirements where allowed in State programs.
(1) Assess significant changes in the watershed and source water as
part of the sanitary survey process and determine appropriate follow-up
action.
(2) Approve watershed control programs for the 0.5 log watershed
control program credit in the microbial toolbox.
(3) Approval protocols for treatment credits under the
Demonstration of Performance toolbox option and for alternative ozone
and chlorine dioxide CT values.
(4) Determine that a system with an uncovered finished water
reservoir has a risk mitigation plan that is adequate for purposes of
waiving the requirement to cover or treat the reservoir.
[FR Doc. 03-18295 Filed 8-8-03; 8:45 am]
BILLING CODE 6560-50-P