Federal Register, Volume 59 Issue 181 (Tuesday, September 20, 1994)

[Federal Register Volume 59, Number 181 (Tuesday, September 20, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-22344]

[[Page Unknown]]

[Federal Register: September 20, 1994]

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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 60

[AD-FRL-5068-5]

Standards of Performance for New Stationary Sources: Municipal
Waste Combustors

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule and notice of public hearing.

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SUMMARY: The EPA is proposing a new subpart Eb to regulate emissions
from new municipal waste combustor (MWC) units for which construction,
modification, or reconstruction began after September 20, 1994.
Today's proposal would implement sections 111 and 129 of the Clean
Air Act (Act). The proposed rule would apply to new MWC units at
facilities with aggregate capacities to combust greater than 35
megagrams per day (Mg/day; a megagram is a metric ton, and one megagram
is equal to 2,204 pounds or about 1.1 short tons) of municipal solid
waste (MSW) and would require sources to achieve emission limits
reflecting the maximum degree of reduction in emissions of air
pollutants that the Administrator determines is achievable, taking into
consideration the cost of achieving such emission reduction, and any
non-air-quality health and environmental impacts and energy
requirements. The proposed rule establishes emission limits for MWC
acid gases (sulfur dioxide (SO2) and hydrogen chloride (HCl)), MWC
metals (particulate matter (PM), opacity, cadmium (Cd), lead (Pb), and
mercury (Hg)), MWC organics (dioxins/furans), nitrogen oxides
(NOx), and MWC fugitive fly ash/bottom ash. The proposed rule
would also establish standards for MWC operating practices (carbon
monoxide (CO), load, flue gas temperature at the PM control device
inlet, and operator training/certification) and siting requirements for
new MWC units.

DATES: Comments. Comments must be received on or before November 21,
1994.
Public Hearing. A public hearing will be held about 15 days
following proposal. See SUPPLEMENTARY INFORMATION for additional
information regarding the public hearing.

ADDRESSES: Comments. Comments on the proposal should be submitted (in
duplicate, if possible) to: Air and Radiation Docket and Information
Center (Mail Code 6102), ATTN: Docket No. A-90-45, Room M1500, U.S.
Environmental Protection Agency, 401 M Street, SW., Washington, DC
20460. See SUPPLEMENTARY INFORMATION for additional information
regarding submittal of comments.
Background Information. The key background information for the
proposal includes: (1) A document entitled ``FACT SHEET: New Municipal
Waste Combustors--Proposed Subpart Eb NSPS,'' which succinctly
summarizes the proposal, and (2) several technical documents listed
under SUPPLEMENTARY INFORMATION, including all of the background
information documents that supported the proposal and promulgation of
the subpart Ca emission guidelines. See SUPPLEMENTARY INFORMATION for
instructions for obtaining these documents.
Docket. Docket Nos. A-89-08 and A-90-45, containing supporting
information used in developing the proposed standards, are located at
the EPA's Air and Radiation Docket and Information Center, Waterside
Mall, Room M1500, Central Mall, 401 M Street, SW., Washington, DC
20460. The docket may also be accessed by calling (202) 260-7548. See
SUPPLEMENTARY INFORMATION for further information regarding the docket.

FOR FURTHER INFORMATION CONTACT: Mr. Walter Stevenson at (919) 541-5264
or Mr. Fred Porter at (919) 541-5251, Standards Development Branch,
Emission Standards Division (MD-13), U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina 27711.

SUPPLEMENTARY INFORMATION:

Background Information

On December 20, 1989, the EPA proposed new source performance
standards (NSPS) for new MWC's in subpart Ea of 40 CFR part 60. The
subpart Ea NSPS were promulgated on February 11, 1991 and were
developed under authority of paragraph (b) of section 111 of the Act of
1977. The Act of 1990 requires the EPA to review these emission
standards and determine if they are fully consistent with the
requirements of section 129. The EPA has reviewed the subpart Ea NSPS
and has concluded that they are not fully consistent with the
requirements of section 129 of the Act of 1990. Therefore, the EPA is
proposing a new NSPS in subpart Eb that would fully comply with the
requirements of section 129. Municipal waste combustors that begin
construction, modification, or reconstruction after September 20, 1994,
and that meet all other applicability criteria, would be subject to the
proposed subpart Eb. Municipal waste combustors that were constructed,
modified, or reconstructed after December 20, 1989 and on or before
September 20, 1994, and that meet all other applicability criteria,
would remain subject to the subpart Ea NSPS and would not be subject to
the proposed subpart Eb NSPS. Those sources subject to subpart Ea
would, however, also be subject to the emission guidelines that are
being proposed under subpart Cb in a separate notice in today's Federal
Register. The proposed subpart Cb emission guidelines would be
applicable to sources constructed, modified, or reconstructed on or
before September 20, 1994.
The Federal Register notices for the proposed NSPS and a proposed
EPA test method that is associated with the NSPS, and the economic
impacts analysis associated with the proposed NSPS are listed below and
are available on the EPA's Technology Transfer Network (TTN) electronic
bulletin board. Also listed below and available on the EPA's TTN is a
FACT SHEET, which succinctly summarizes the proposal and is suggested
reading for persons requiring a limited overview of the proposal. The
TTN contains 18 electronic bulletin boards, and the items listed below
are included in the Clean Air Act Amendments (CAAA) bulletin board and
the Emissions Measurement Technical Information Center (EMTIC) bulletin
board. The FACT SHEET can also be obtained by calling Ms. Cassie Posey
at (919) 541-0069.

MWC Items in the CAAA Electronic Bulletin Board

(1) ``FACT SHEET: New Municipal Waste Combustors--Subpart Eb
Proposed NSPS.''
(2) Federal Register notice for this proposal: ``Standards of
Performance for New Stationary Sources: Municipal Waste Combustors''
(this document).
(3) ``Economic Impact Analysis for Proposed Emission Standards and
Guidelines for Municipal Waste Combustors,'' EPA-450/3-91-029, March
1994.

MWC Items in the EMTIC Electronic Bulletin Board

1. ``Emissions Test Method 29: Determination of Metals Emissions
from Stationary Sources (1994 Proposal),'' EPA-454/R-94-016, April 1994
(the document includes both the Federal Register proposal notice
(chapter 1) and the full text of the rationale and regulations for the
proposal (chapter 2)).
The TTN is accessible 24 hours per day, 7 days per week, except
Monday morning from 8 a.m. to 12 p.m., when the system is updated. The
service is free, except for the cost of the phone call. Dial (919) 541-
5742 to access the TTN. The TTN is compatible with up to a 14,400 bits-
per-second (bps) modem. Further instructions for accessing the TTN can
be obtained by calling the help desk at (919) 541-5384.
The background information for today's proposal includes all of the
documents that supported the proposal and promulgation of the subpart
Ea NSPS (Docket No. A-89-08), as well as information in Docket No. A-
90-45. Key background information documents used in developing the
subpart Ea NSPS and today's proposed standards are as follows:
(1) ``Municipal Waste Combustors--Background Information for
Proposed Standards: 111(b) Model Plant Description and Cost Report,''
EPA-450/3-89-27b, August 1989;
(2) ``Municipal Waste Combustors--Background Information for
Proposed Standards: Post-Combustion Technology Performance,'' EPA-450/
3-89-27c, August 1989;
(3) ``Municipal Waste Combustion Assessment: Combustion Control at
Existing Facilities,'' EPA-600/8-89-057, August 1989;
(4) ``Municipal Waste Combustion Assessment, Technical Basis for
Good Combustion Practices,'' EPA-600/8-89-063, August 1989;
(5) ``Municipal Waste Combustors--Background Information for
Proposed Standards: Control of NOX Emissions,'' EPA-450/3-89-27d,
August 1989;
(6) ``Municipal Waste Combustors--Background Information for
Proposed Standards: Cost Procedures,'' EPA-450/3-89-27a, August 1989;
and
(7) ``Economic Impact Analysis for Proposed Emission Standards and
Guidelines for Municipal Waste Combustors,'' EPA-450/3-91-029, March
1994.
Docket Nos. A-89-08 and A-90-45 are available for public inspection
and copying between 8 a.m. and 4 p.m., Monday through Friday, at the
location specified in the ADDRESSES section of this preamble. A
reasonable fee may be charged for copying. Additionally, the docket may
be accessed by telephone, as specified in the ADDRESSES section.
Comments. Today's action is a proposal and comments are requested.
The MWC regulations are complex, and the EPA expects to receive
numerous comments on this proposal. The EPA has specifically requested
comments on items fundamental to the proposal, including but not
limited to the MACT floor, MACT performance levels, and materials
separation plans. The EPA seeks full public participation in arriving
at its final decisions, and strongly encourages comments on all aspects
of this proposal from all interested parties. Whenever applicable, full
supporting data and detailed analyses should be submitted with all
comments to allow the EPA to respond to the comments.
Commenters wishing to submit proprietary information for
consideration should clearly distinguish such information from other
comments, and clearly label it ``Confidential Business Information.''
Submissions containing such proprietary information should be sent
directly to the following address, and not to the public docket, to
ensure that proprietary information is not inadvertently placed in the
docket: Attention: Mr. Walter Stevenson, c/o Ms. Melva Toomer, U.S. EPA
Confidential Business Manager, 411 W. Chapel Hill Street, Room 944,
Durham, North Carolina 27701. Information covered by such a claim of
confidentiality will be disclosed by the EPA only to the extent allowed
and by the procedures set forth in 40 CFR part 2. If no claim of
confidentiality accompanies a submission when it is received by the
EPA, it may be made available to the public without further notice to
the commenter.
Public Hearing. The public hearing will be held to provide
interested parties an opportunity for oral presentations of data,
views, or arguments concerning the proposed standards (see DATES for
the hearing schedule). The public hearing will be held at Research
Triangle Park, North Carolina, and will start at about 9 a.m. Persons
wishing to present oral testimony at the public hearing must call Ms.
Julia Latta at (919) 541-5578 at least 2 days in advance of the public
hearing. Persons interested in attending the hearing should also call
Ms. Latta to verify the time, date, and location of the hearing.
Persons may call (919) 541-5264 to hear a recorded message that
provides current information on the status of the public hearing.
Preamble Outline. The following outline is provided to aid in
locating information in this preamble.
I. Introduction
A. Summary of Regulatory Decisions
B. New Source Performance Standards--General Goals
C. Overview of this Preamble
II. Summary of the Proposed Subpart Eb Standards
A. Source Category to be Regulated
B. Pollutants to be Regulated
C. Format for the Proposed Standards
D. Proposed Standards
E. Comparison of the 1991 NSPS and Today's Proposed NSPS
F. Performance Testing and Monitoring Requirements
G. Reporting and Recordkeeping Requirements
III. Impacts of the Proposed Standards
A. Incremental Impacts of the Proposed NSPS over the 1991 NSPS
B. Impacts of the Proposed NSPS Over a Pre-1989 Baseline
IV. Rationale for Proposed Standards for MWC Emissions
A. Background
B. Selection of Source Category
C. Modification or Reconstruction of Existing MWC's
D. Selection of Designated Pollutants
E. Selection of Affected Facilities
F. Selection of Maximum Achievable Control Technology
G. Selection of Format for the Proposed Standards
H. Performance Test Methods and Monitoring Requirements
I. Reporting and Recordkeeping Requirements
V. Rationale for the Proposed Standards for Siting Requirements
A. Overview
B. Siting Analysis
C. Materials Separation Plan
D. Public Meeting and Reporting Requirements
VI. Rationale for the Proposed Standards for Fugitive Fly Ash/Bottom
Ash Emissions
A. Background
B. Fugitive Emission Control Techniques
C. Proposed Fugitive Emissions Standards
VII. Proposed Standards for Air Curtain Incinerators
VIII. Comparison of the Proposal and European Emission Limits
IX. Miscellaneous
X. Administrative Requirements
A. Public Hearing
B. Docket
C. Clean Air Act Procedural Requirements
D. Office of Management and Budget Reviews
E. Regulatory Flexibility Act Compliance

I. Introduction

This section provides an introduction to the proposed rule by: (1)
Summarizing the history of the development of NSPS for new MWC's over
the past 7 years; (2) summarizing the general goals of the proposed
rule that are specified by sections 111(d) and 129 of the Act of 1990;
and (3) providing a brief overview of the major issues discussed in
this preamble.

A. Summary of Regulatory Decisions

During the early and mid-1980's, several studies were performed to
determine whether MWC emissions should be regulated and, if so, under
what section of the Act. As set forth in the advance notice of proposed
rulemaking (ANPRM) (52 FR 25399, July 7, 1987), the EPA decided to
regulate air emissions from MWC's under section 111 of the Act, and
based the regulation on best demonstrated technology (BDT), as required
by section 111. On December 20, 1989, the EPA proposed NSPS for new
MWC's and emission guidelines for existing MWC's (54 FR 52251 and 54 FR
52209, respectively). On November 15, 1990, the Clean Air Act
Amendments of 1990 were enacted and added section 129 to the Act.
Section 129 of the Act specifies that revised NSPS and emission
guidelines must be developed for MWC's in accordance with the
requirements of sections 111 and 129. Section 129 further specifies
that revised NSPS and emission guidelines be developed for both large
and small MWC's and that the revised NSPS and emission guidelines must
reflect a more restrictive standard of performance. Section 129
includes a schedule for revising the 1991 NSPS. When the EPA did not
comply with that schedule, the Sierra Club and the Natural Resources
Defense Council (NRDC) filed a complaint with the U.S. District Court
for the Eastern District of New York. The resulting consent decree
requires the EPA Administrator to sign a notice of proposed rulemaking
not later than September 1, 1994 and a notice of promulgation not later
than September 1, 1995 (Nos. CV-92-2093 and CV-93-0284).
The NSPS and guidelines promulgated on February 11, 1991 (56 FR
5488 and 56 FR 5514, respectively) apply to MWC's with unit capacities
above 225 Mg/day and reflect BDT as determined by the Administrator at
the time those standards were issued. Today's notice therefore proposes
to create new NSPS to be fully consistent with sections 111 and 129 of
the Act and to extend coverage of the standards to new MWC units
located at MWC facilities with aggregate plant capacity above 35 Mg/
day. Additionally, under a separate notice in today's Federal Register,
new subpart Cb emission guidelines for existing MWC plants with
aggregate capacities above 35 Mg/day of MSW are being proposed pursuant
to sections 111 and 129 of the Act.
Today's proposed NSPS is more stringent than the NSPS promulgated
on February 11, 1991. Today's proposed NSPS would replace the subpart
Ea NSPS for those facilities for which construction, modification, or
reconstruction commenced after September 20, 1994. However, the
February 11, 1991 subpart Ea NSPS will remain in effect for affected
facilities constructed, modified, or reconstructed after December 20,
1989 and on or before September 20, 1994. Those sources subject to the
February 11, 1991 subpart Ea NSPS would also be subject to the emission
guidelines being proposed under subpart Cb in a separate notice in
today's Federal Register. In most cases, the proposed subpart Cb
emission guidelines are more stringent than the existing subpart Ea
standards.

B. New Source Performance Standards--General Goals

The Act requires the promulgation of performance standards under
section 111 for categories of new and existing stationary sources that
may contribute to air pollution that may reasonably be anticipated to
endanger public health or welfare. Section 129 of the Act specifies
that NSPS and emission guidelines must be developed for MWC's in
accordance with the requirements of sections 111 and 129 of the Act.
Section 129(a)(2) provides that the revised standards for new MWC's
reflect the maximum degree of reduction in emissions of designated air
pollutants, taking into consideration the cost of achieving such
emission reduction, and any non-air-quality health and environmental
impacts and energy requirements that the Administrator determines are
achievable for a particular category of sources (this standard is
commonly referred to as ``maximum achievable control technology, or
``MACT''). Additionally section 129 provides that standards for new
sources may not be less stringent than the emissions control achieved
in practice by the best controlled similar unit. This is referred to as
the ``MACT floor.'' The standards themselves are set forth as emission
limits and do not specify what technology must be applied.

C. Overview of this Preamble

This preamble will:
(1) Summarize the proposed standards by discussing the conclusions
reached with respect to each of the elements in the decision summary;
(2) Describe the environmental, energy, and economic impacts of the
proposed standards;
(3) Present a rationale for each of the decisions associated with
this proposal;
(4) Present a regulatory flexibility analysis; and
(5) Discuss administrative requirements relevant to this action.

II. Summary of the Proposed Subpart Eb Standards

This section presents a summary of the proposed NSPS, including
identification of the source category and pollutants that would be
regulated under the proposal, discussion of the format of the proposed
standards, and presentation of the proposed standards and their
associated performance testing, monitoring, recordkeeping and reporting
requirements. This section also provides a comparison of the emission
standards in this proposed subpart Eb NSPS versus the 1991 subpart Ea
NSPS.

A. Source Category to be Regulated

Today's proposed standards would apply to each MWC unit located at
an MWC facility that has an aggregate plant capacity to combust over 35
Mg/day of MSW, for which construction, modification, or reconstruction
commenced after September 20, 1994. Additionally, under the proposed
NSPS, plants with an aggregate capacity to combust between 25 and 35
Mg/day would be required to submit an initial report of their facility
capacities and location, but would not be subject to any other
provisions of the NSPS. Municipal waste combustors that commenced
construction, modification, reconstruction on or before September 20,
1994 are not covered under today's proposed standards, but are being
addressed in a separate notice in today's Federal Register.
An MWC is defined as any setting or equipment that combusts MSW.
Municipal solid waste combustion includes the burning (or pyrolysis) of
MSW in any type of setting or equipment, including combustion equipment
with or without heat recovery. This definition has been slightly
modified from the February 11, 1991 NSPS and is discussed below.
Municipal solid waste is defined as either a mixture or a single-
item stream of household, commercial, and/or institutional discards.
This would include materials such as paper, wood, yard wastes, tree
trimmings, plastics, leather, rubber, glass, metals, and other
combustible and noncombustible materials. The MSW definition includes
household discards as well as discards from institutional and
commercial sources, but does not include industrial process or
manufacturing discards. The definition of MSW also includes refuse-
derived fuel (RDF), which is solid waste that is shredded (or
pelletized) and classified by size before combustion. Municipal solid
waste does not, however, include wastes that are solely segregated
medical wastes. However, if segregated medical wastes are mixed with
MSW, the resulting mixture remains MSW, and the proposed standards
would apply if the aggregate MWC plant capacity exceeded 35 Mg/day
capacity. Minor editing changes are proposed in the definition of MSW
to clarify this point.
Air curtain incinerators that combust MSW are MWC's. However, air
curtain incinerators that burn only yard wastes, tree trimmings, and
clean untreated lumber would be covered under a separate set of
proposed opacity emission limits, and no other part of the proposal
would apply. Air curtain incinerator opacity requirements are discussed
in section VII of this preamble.

B. Pollutants to be Regulated

Section 129 of the Act requires the EPA to establish numerical
emission limits specifically for SO2, HCl, PM, opacity, Cd, Pb,
Hg, dioxins/furans, CO, and NOX. Section 129 specifies that the
EPA may also

* * * promulgate numerical emission limitations or provide for
the monitoring of post-combustion concentrations of surrogate
substances, parameters, or periods of residence times in excess of
stated temperatures with respect to pollutants other than those
listed [above]. * * *

Therefore, the EPA is proposing standards for load and flue gas
temperature at the PM control device inlet as additional indicators of
MWC operating practices. The EPA is also proposing a standard for fly
ash/bottom ash fugitive emissions because these emissions include Cd,
Pb, Hg, and dioxins/furans (see section VI of this preamble for further
discussion of the EPA's decision to regulate fugitive emissions from
MWC's).
The February 11, 1991 NSPS includes standards for all of the
pollutants listed above except Cd, Pb, Hg, and fly ash/bottom ash
fugitive emissions. The proposed NSPS would establish standards for all
of the pollutants listed above. The proposed standards for the same
pollutants regulated by the February 11, 1991 NSPS (i.e., SO2,
HCl, PM, opacity, dioxins/furans, NOX, CO, load, and flue gas
temperature at the PM control device inlet) would be revised under the
proposal to reflect the requirements of section 129.

C. Format for the Proposed Standards

The format of the proposed standards is similar to the format of
the February 11, 1991 NSPS. In most cases, the format is in the form of
emission limits (concentrations).
The February 11, 1991 NSPS specifies emission limits for PM and
opacity. Particulate matter is measured as a concentration (milligrams
per dry standard cubic meter (mg/dscm)) and is corrected to 7 percent
oxygen (O2), and opacity is measured on a percentage basis. The
format for the PM and opacity standards would not change in today's
proposal, but Cd, Pb, and Hg emission limits would be added. Emissions
of Cd, Pb, and Hg would be calculated as a concentration (mg/dscm)
corrected to 7 percent O2, dry basis. For Hg, today's proposed
standards would also establish an alternative percentage reduction
requirement. A new method (Method 29) that would measure these
pollutants is being proposed in a separate part of today's Federal
Register.
The February 11, 1991 NSPS establishes control requirements for
SO2 and HCl (MWC acid gases) by specifying both numerical emission
limits and alternative percentage reduction requirements for both
SO2 and HCl. The concentration emission limits for HCl and
SO2 are calculated as parts per million by volume (ppmv) corrected
to 7 percent O2, dry basis. Today's proposed standards for
SO2 and HCl would also be based on the same format.
The February 11, 1991 NSPS addresses a numerical emission limit for
NOX emissions. The concentration emission limit for NOX is
calculated as ppmv. Today's proposed standard for NOX is based on
the same format as the February 11, 1991 NSPS.
The February 11, 1991 NSPS establishes MWC organics control by
specifying an emission limit for dioxins/furans. The format of the
dioxin/furan emission limit would be revised by today's proposal. In
the February 11, 1991 NSPS, emissions of dioxins/furans are calculated
as a concentration (nanograms per dry standard cubic meter (ng/dscm))
corrected to 7 percent O2, dry basis, on a total mass basis (i.e.,
the mass of all tetra- through octa- congeners were added together). In
today's proposal, dioxin/furan emissions could be reported either in
units of ng/dscm toxic equivalency (TEQ) or in units of ng/dscm total
mass dioxins/furans. Reporting in TEQ units is done by first measuring
the total mass of dioxin/furan congeners and then adjusting the results
for the toxicity of each dioxin/furan congener. The same test method
(Method 23) is used in either case. See section II.F of this preamble
for further discussion of the proposed method of reporting dioxin/furan
emissions in terms of TEQ.
In addition to controlling stack emissions, the February 11, 1991
NSPS also establishes good combustion operating standards for MWC's.
These operating standards are part of good combustion practices (GCP)
and ensure that emissions of MWC organics (dioxins/furans) are
minimized on a continuous basis. The GCP requirements are included in
today's proposal, but they are being extended to apply to MWC's at
plants of 35 Mg/day aggregate capacity or larger. Additionally, some
minor revisions are being proposed. The proposed revisions would
include: (1) A requirement that all shift operators and chief facility
operators obtain full operator certification, (2) ``stand in''
authority for MWC control room operators, and (3) required training of
MWC shift supervisors. These items are discussed below.
The February 11, 1991 NSPS requires provisional certification of
the chief facility operator and shift supervisors by the American
Society of Mechanical Engineers (ASME) or a State certification
program. Development of a site-specific training manual to be used for
training other MWC personnel is also required. Today's proposal would
require that the chief facility operator and shift supervisor obtain
both provisional and then full operator certification.
Today's proposal would also allow for the optional certification of
one or more control room operators. Under the February 11, 1991 NSPS,
all chief facility operators and shift supervisors shall be certified,
and one of these individuals must be onsite during all periods of MWC
operation. Under today's proposal, a provisionally certified control
room operator may ``stand in'' for the chief facility operator or shift
supervisor during periods in which the certified chief facility
operator or certified shift supervisor is offsite, in order to fulfill
the requirement that a certified individual be onsite during all
periods of MWC operation. This would provide additional operating
flexibility. Today's proposal would also require that all chief
facility operators, shift supervisors, and control room operators
complete the EPA or a State MWC operator training course. The EPA has
developed a model training program that has been distributed to State
air pollution control agencies, the EPA Regional Offices, and MWC
industry groups. The EPA believes that operator training is an integral
part of the implementation of GCP.
Today's proposed standards would establish siting requirements for
all new MWC's at plants with aggregate capacities above 35 Mg/day.
These siting requirements would include three components. First, an
analysis of the impact of the facility on ambient air quality,
visibility, soils, and vegetation would be required. Second, the siting
requirements would include submittal of a materials separation plan for
the area served by the affected facility. Third, the MWC owner or
operator would be required to make both the siting analysis and the
materials separation plan available to the public, hold public meetings
to receive comments on the siting analysis and materials separation
plan, and respond in writing to the comments received. These siting
requirements were not included in the February 11, 1991 NSPS. See
section V.D of this preamble for a more detailed discussion of the
proposed siting requirements.
Today's proposed standards also establish standards for fugitive
fly ash/bottom ash emissions from ash handling facilities. The proposed
standards would establish visible emissions limits for emissions of ash
from buildings where ash was transferred and from external ash transfer
equipment and ash handling areas at the MWC facility. This requirement
was not included in the February 11, 1991 NSPS.

D. Proposed Standards

Today's proposal would establish standards for MWC acid gases
(SO2 and HCl), MWC metals (PM, opacity, Cd, Pb, and Hg), MWC
organics (dioxins/furans), and NOX. The proposed standards also
include requirements for fly ash/bottom ash fugitive handling, MWC
operating practices (CO, load, and flue gas temperature), operator
training and certification, and siting for new MWC units.
The proposed NSPS would divide the MWC population into two
subcategories: The first would be for MWC units located at small MWC
plants (i.e., those with aggregate capacities to combust greater than
35 Mg/day of MSW but equal to or less than 225 Mg/day), and the second
would be for MWC units at large plants (i.e., those with aggregate
capacities to combust more than 225 Mg/day of MSW). The aggregate
capacity of all MWC units at one site constructed after September 20,
1994 would be added together to define aggregate MWC plant capacity for
determining NSPS applicability.
The proposed NSPS for each subcategory of MWC's are summarized in
table 1. The proposed NSPS are also discussed briefly below.

Table 1. Summary of Proposed NSPS for New MWC's
[Subpart Eb]^{a
------------------------------------------------------------------------
Plant size (MSW combustion
capacity) Requirement
------------------------------------------------------------------------
Applicability

The proposed NSPS would apply to
new MWC units located at plants
with capacities to combust greater
than 25 Mg/day of residential,
commercial, and/or institutional
discards.^{b Industrial discards are
not covered by the proposed NSPS.

25 Mg/day........... Not covered by standards.
>25 Mg/day but 35 Initial report of MWC design
Mg/day. capacity and startup date.
>35 Mg/day but 225 Subject to provisions listed below.
Mg/day (referred to as small
MWC plants).
>225 Mg/day (referred to as Subject to provisions listed below.
large MWC plants).
------------------------------------------------------------------------

Good Combustion Practices:
Applies to large and small MWC plants.
A site-specific operator training manual would be required to
be developed and made available for MWC personnel. The EPA or State
MWC operator training course would be required to be completed by the
MWC chief facility operator, shift supervisors, and control room
operators.
The ASME or a State MWC operator certification would be
required to be obtained by the MWC chief facility operator
(mandatory), shift supervisors (mandatory), and control room
operators (optional).
The MWC load level would be required to be measured and not to
exceed the maximum load level as demonstrated during the most recent
dioxin/furan performance test.
The PM control device inlet flue gas temperature would be
required to be measured and not to exceed the level demonstrated
during the most recent dioxin/furan performance test.
The CO level would be required to be measured using CEMS, and
the concentration in the flue gas would be required not to exceed the
following.

------------------------------------------------------------------------
MWC type CO Level^{c Averaging time
------------------------------------------------------------------------
Modular starved-air and excessair....... 50 ppmv 4-hour.
Mass burn waterwall and refractory...... 100 ppmv 4-hour.
Mass burn rotary refractory............. 100 ppmv 4-hour.
Fluidized-bed combustion................ 100 ppmv 4-hour.
Coal/RDF mixed fuel-fired............... 150 ppmv 4-hour.
RDF stokers............................. 150 ppmv 24-hour.
Mass burn rotary waterwall.............. 100 ppmv 24-hour.
------------------------------------------------------------------------

MWC Organic Emissions (measured as dioxin/furan)^{c,d
Dioxins/furans (compliance test by EPA Reference Method 23)

Large and small MWC plants..... 13 ng/dscm total mass or 0.20 ng/
dscm dioxin/furan TEQ^{e.
Basis for dioxin/furan GCP and SD/FF/CI.
standard.

MWC Metal Emissions^{c

PM (compliance test by EPA Reference Method 5)

Large and small MWC plants..... 15 mg/dscm (0.007 gr/dscf).

Opacity (compliance test by EPA Reference Method 9)

Large and small MWC plants..... 10 percent (6-minute average).

Cd (compliance test by EPA Reference Method 29)^{f

Large and small MWC plants..... 0.010 mg/dscm (4.4 gr/million
dscf).

Pb (compliance test by EPA Reference Method 29)^{f

Large and small MWC plants..... 0.10 mg/dscm (44 gr/million dscf).

Hg (compliance test by EPA Reference Method 29)^{f

Large and small MWC plants..... 0.080 mg/dscm (35 gr/million dscf)
or 85-percent reduction in Hg
emissions.
Basis for PM, opacity, Cd, Pb, and Hg standards

Large and small MWC plants..... See basis for dioxin/furan
standard.

MWC Acid Gas Emissions^{c

SO2 (compliance test by CEMS)

Large and small MWC plants..... 30 ppmv or 80-percent reduction in
SO2 emissions (24-hour).

HCl (compliance test by EPA Reference Method 26)

Large and small MWC plants..... 25 ppmv or 95-percent reduction in
HCl emissions.
Basis for SO2 and HC1 See basis for dioxin/furan
standards. standard.

Nitrogen Oxides Emissions^{c

NOX (compliance test by CEMS)

Large MWC plants............... 180 ppmv.
Small MWC plants............... No NOX control requirement.

Basis for NOx standard
Large MWC plants............... SNCR.
Small MWC plants............... No NOX control requirement.

Fly Ash/Bottom Ash Fugitive Emissions

Fly Ash/Bottom Ash (compliance test by EPA Reference Method 22)

Large and small MWC plants..... No visible emissions from
buildings, ash transfer points, or
ash handling areas.
Basis for fugitive Wet ash handling or enclosed ash
emissions standard handling.

Siting Requirements

Large and small MWC (1) Siting analysis, (2) materials
plants. separation plan, and (3) public
meetings (including response to
comments)^{g.

Compliance Testing and Monitoring Requirements

Load, flue gas Continuous monitoring, 4-hour
temperature. arithmetic average.
CO..................... CEMS, 4- or 24-hour arithmetic
average, as applicable.

Dioxins/furans^{d, PM, Cd, Pb, Hg, and HCl

Large MWC plants............... Annual stack test.
Small MWC plants............... Annual or third year stack test^{h.
Opacity................ COMS (6-minute average) and annual
stack test.
SO2.................... CEMS, 24-hour geometric mean.
NOX (large MWC plants CEMS, 24-hour arithmetic average.
only).
Fly ash/bottom ash Annual test.
fugitive emissions.
^{aDefinition of Abbreviations Used in Table:
ASME=American Society of Mechanical Engineers
Cd=cadmium
CEMS=continuous emission monitoring system
CO=carbon monoxide
COMS=continuous opacity monitoring system
GCP=good combustion practices
gr/dscf=grains per dry standard cubic foot
gr/million dscf=grains per million dry standard cubic feet
HCl=hydrogen chloride
Hg=mercury
Mg/day=megagrams per day (1 Mg/day=1.1 short tons/day (2,204 pounds/
day))
mg/dscm=milligrams per dry standard cubic meter (100 mg/dscm=0.044 gr/
dscf)
MSW=municipal solid waste
MWC=municipal waste combustor
ng/dscm=nanograms per dry standard cubic meter (1,000,000 ng=1 mg)
NOX=nitrogen oxides
NSPS=new source performance standards
Pb=lead
PM=particulate matter
ppmv=parts per million by volume
RDF=refuse-derived fuel
SD/FF/CI=spray dryer/fabric filter/activated carbon injection
SNCR=selective noncatalytic reduction
SO2=sulfur dioxide
TEQ=toxic equivalency of 2,3,7,8- tetrachlorinated dibenzo-p-dioxin
(North Atlantic Treaty Organization (NATO) 1989 international
criteria)
Total mass=total mass of tetra- through octa-chlorinated dibenzo-p-
dioxins and dibenzofurans.
^{bAir curtain incinerators that combust only yard wastes, tree trimmings,
and/or clean lumber would be subject to an opacity emission limit but
to no other parts of the proposed NSPS. Air curtain incinerators that
combust other MSW are subject to all requirements under the proposed
NSPS.
^{cAll concentration levels in the table are corrected to 7 percent O2,
dry basis.
^{dDioxins/furans measured as total tetra- through octa-chlorinated
dibenzo-p-dioxins and dibenzofurans. For plants complying with the TEQ
format of the standard, TEQ is determined using 1989 international
toxicity equivalency factors.
^{eFor MWC's constructed after September 20, 1994, but on or before
September 22, 1997, the standard would be 0.50 ng/dscm TEQ or 30 ng/
dscm total mass for the first 3 years of operation of the MWC. After
the first 3 years, the standard would be 0.20 ng/dscm TEQ or 13 ng/
dscm total mass. For all MWC's constructed after September 22, 1997,
the standard at startup would be 0.20 ng/dscm TEQ or 13 ng/dscm total
mass.
^{fMethod 29 is being proposed in a separate notice in today's Federal
Register.
^{gTwo public meetings would be held for review of the materials
separation plan. The first public meeting would focus on review of a
draft materials separation plan. The draft materials separation plan
and the summary of responses to public comments about the plan would
be submitted to EPA prior to application for a construction permit
under New Source Review (NSR). A second public meeting would be held
after submission of the application for a construction permit and
would focus on both the final materials separation plan and the siting
analysis. The siting analysis, the materials separation plan, and the
summary of responses to public comments on the siting analysis and the
materials separation plan would be submitted as part of the initial
notification of construction.
^{hThe proposed NSPS includes provisions that would allow small MWC plants
to conduct performance tests for dioxins/furans, PM, Cd, Pb, Hg, and
HCl every third year if the MWC meets certain specified criteria
discussed in section II.F of this preamble.

The proposed standards are summarized below.

1. Municipal Waste Combustor Organics

The proposed standards for MWC organics would require new MWC's at
MWC plants with capacities above 35 Mg/day for which construction
commences after September 20, 1994, but on or before September 22,
1997, to meet a dioxin/furan emission limit of either 0.50 ng/dscm TEQ
or 30 ng/dscm total mass, at 7 percent O2 for the first 3 years
following the date of initial startup. Thereafter, the standard would
be 0.20 ng/dscm TEQ or 13 ng/dscm total mass. For MWC's at plants with
capacities above 35 Mg/day for which construction commences after
September 22, 1997, the standard at startup would be 0.20 ng/dscm TEQ
or 13 ng/dscm total mass. Emissions reported in TEQ would be calculated
using the 1989 North Atlantic Treaty Organization (NATO) international
toxic equivalency factors (TEF's), using the methods described in
section II.F of this preamble and section 60.58b of the proposed
subpart Eb NSPS.

2. Municipal Waste Combustor Metals

The proposed standards for MWC metals would require all MWC's at
MWC plants with capacities above 35 Mg/day to meet a PM emission limit
of 15 mg/dscm at 7 percent O2. Municipal waste combustors at both
large and small MWC plants would also be required to meet an opacity
limit of 10 percent based on a 6-minute averaging period.
The proposed standards would also establish specific emission
levels for Cd, Pb, and Hg. The proposed standards would require new
MWC's at MWC plants with capacities above 35 Mg/day to meet a Cd limit
of 0.010 mg/dscm, a Pb limit of 0.10 mg/dscm, and an Hg limit of 0.080
mg/dscm or an 85-percent reduction in potential Hg emissions. These
proposed emission limits are corrected to 7 percent O2 on a dry
basis.

3. Municipal Waste Combustor Acid Gases

The proposed standards for MWC acid gases would require MWC's at
plants with capacities above 35 Mg/day to meet an HCl emission limit of
either 25 ppmv or 95-percent reduction (at 7 percent O2, dry
basis). These MWC plants would also be required to achieve an SO2
emission limit of either 30 ppmv or 80-percent reduction (at 7 percent
O2, dry basis, on a 24-hour geometric mean basis, measured
continuously).

4. Good Combustion Practices

Today's proposed NSPS would require all new MWC's at MWC plants
with capacities above 35 Mg/day to comply with specific operating
practices that reflect GCP. These operating practices include CO
emission limits, combustor load levels, and flue gas temperatures at
the inlet to the PM control device.
The GCP CO levels remain basically unchanged from the February 11,
1991 NSPS. For modular starved-air and modular excess-air types of
MWC's, the CO emission limit would be 50 ppmv (at 7 percent O2,
dry basis) on a 4-hour block average basis. For mass burn waterwall,
mass burn refractory (rotary and fixed-wall), and fluidized-bed types
of MWC's, the CO emission limit would be 100 ppmv (at 7 percent
O2, dry basis) on a 4-hour block average basis. For mass burn
rotary waterwall MWC's, the CO emission limit would be 100 ppmv (at 7
percent O2, dry basis) on a 24-hour block average basis. For RDF-
stoker MWC's, the CO limit would be 150 ppmv (at 7 percent O2, dry
basis) on a 24-hour block average basis. For coal/RDF mixed fuel-fired
MWC's, the CO limit would be 150 ppmv (at 7 percent O2, dry basis)
on a 4-hour block average basis. These limits remain unchanged from the
February 11, 1991 NSPS except that a limit specifically for mass burn
rotary refractory units has been added for clarification.
Municipal waste combustors would be allowed to operate up to 110
percent of the maximum capacity, as achieved during the most recent
dioxin/furan compliance test. Maximum capacity would be based on the
steam flow rate, which would be continuously monitored according to the
ASME Power Test Code (PTC) for Steam Generating Units (PTC4.1 and
PTC19.5). This requirement is unchanged from the February 11, 1991
NSPS. The EPA requests comments on this method of measuring load for
steam-generating MWC's. Specifically, the EPA has questions regarding
the requirement for calibration of the measuring device (e.g., orifice
plate) before and after each dioxin/furan compliance test. The EPA is
concerned that this calibration requirement may be overly burdensome
because the main steam line that contains the orifice plate may need to
be cut in order to access the orifice plate for recalibration. Also,
the EPA requests comments on whether the ASME PTC adequately addresses
the need for calibrating the signal from the flow meter.
Additionally, the EPA requests comments on the use of boiler feed
water flow as an alternative method for continuously monitoring load
for steam-generating MWC's.
Furthermore, the EPA is considering allowing the use of the
continuous flue gas volumetric flow rate to measure maximum capacity
for both steam-generating MWC's, as well as those MWC's that do not
generate steam. These types of monitors are based on ultrasonic,
thermal, or differential pressure methods, and are now being required
as part of the EPA's Acid Rain Program (40 CFR part 75). The EPA
requests comments on whether continuous flue gas volumetric flow rate
monitors are adequately demonstrated and accurate methods for
determining compliance with the load level requirements, and if they
should be allowed as an alternative to the use of the ASME PTC.
Under the NSPS, MWC's would establish a site-specific maximum flue
gas temperature at the final PM control device inlet demonstrated
during their most recent dioxin/furan compliance test. Similar to the
provisions for establishing a maximum load level measurement, the
maximum demonstrated PM control device inlet temperature is established
as the maximum 4-hour block average temperature measured during the
most recent dioxin/furan compliance test. The MWC must then be operated
so that the temperature at the final PM control device inlet does not
exceed this level by more than 17 deg.C (30 deg.F) (4-hour block
average basis).

5. Operator Certification and Training

The proposed NSPS would require full operator certification of all
MWC shift supervisors and MWC chief facility operators by the ASME or a
State certification program. The proposed standards would also require
that at least one of the following persons be on duty at all times
during which the MWC is combusting waste: A fully certified chief
facility operator, a fully certified shift supervisor, or a
provisionally certified control room operator. A provisionally
certified control room operator would be allowed to ``stand in'' during
times a fully certified chief facility operator or shift supervisor is
offsite. These requirements would become effective on the date of
promulgation of the NSPS or 6 months after startup of a new MWC,
whichever is later.
In addition, the proposed NSPS would require each owner or operator
of an MWC plant with an aggregate capacity greater than 35 Mg/day to
develop and maintain a site-specific training manual and to review it
with all employees associated with the operation of the MWC (including
MWC maintenance personnel, crane/load operators, and ash handlers). The
manual and training would be updated annually. This site-specific
training requirement would be effective on the date of promulgation of
the NSPS or 6 months after startup of a new MWC, whichever is later.
Section 129 of the Act of 1990 requires the EPA to develop and
promote a model program for the training and certification of MWC
operators. Section 129 specifies that ``any person with control over
processes affecting emissions from a unit'' must successfully complete
an acceptable training program. Consistent with section 129, today's
proposed revisions would require all MWC chief facility operators,
shift supervisors, and control room operators to complete the EPA or a
State MWC operator training course before operating an MWC or within 6
months following promulgation of the standards, whichever is later. The
EPA has developed a model training program and has distributed it to
State air pollution control agencies, EPA regional offices, and MWC
industry groups. This model training program could be used to fulfill
this requirement and prepare for the ASME certification.

6. Nitrogen Oxides Emissions

The proposed standards include a NOX control requirement for
MWC's at large plants and would require these MWC's to meet a NOX
emission limit of 180 ppmv (corrected to 7 percent O2, dry basis,
on a 24-hour daily average basis). A ``no control'' NOX emission
limit for MWC's at small plants is also proposed and is discussed in
section VII of this preamble.

7. Siting Requirements

Siting requirements are being proposed for all new MWC's at plants
with capacities above 35 Mg/day. These siting requirements are not
included in the 1991 subpart Ea NSPS. The siting requirements would
include the following three components: (1) A siting analysis, (2) a
materials separation plan, and (3) public meetings. The siting analysis
would address the impact of the facility, taking into account other
major industrial facilities near the proposed site, on ambient air
quality, visibility, soils, vegetation, and other factors that may be
relevant in determining that the benefits of the proposed facility
significantly outweigh the environmental and social costs imposed as a
result of its location and construction. The materials separation plan
would summarize materials separation requirements for the facility and
its service area. Following public meetings on the siting analysis and
materials separation plan, the facility would be required to prepare
transcripts of the public meetings and summaries of comments and
responses for the public meetings.

8. Fly Ash/Bottom Ash Fugitive Emissions

Standards are proposed for fly ash/bottom ash fugitive dust
emissions from ash handling and storage facilities at all MWC's at
plants above 35 Mg/day capacity. The proposed standards would establish
a no visible emissions limit for fly ash/bottom ash handling and would
apply to ash handling, conditioning, loading and storage buildings, any
external ash conveyors, ash transfer points, or ash handling activities
(e.g., truck loading), and any other area at the facility that is a
potential source of fly ash or bottom ash fugitive emissions.

E. Comparison of the 1991 NSPS and Today's Proposed NSPS

The subpart Ea NSPS promulgated on February 11, 1991 and today's
proposed subpart Eb standards both include emission limits for dioxins/
furans, PM, SO2, HCl, and NOX; however, today's proposed
standards for most of these pollutants are more stringent than the NSPS
promulgated on February 11, 1991. The February 11, 1991 NSPS did not
address Cd, Pb, Hg, or fly ash/bottom ash fugitive emissions, but these
pollutants are included in today's proposal. Also, today's proposal
would apply to all MWC units at plants with aggregate capacities above
35 Mg/day, whereas the February 11, 1991 NSPS only included MWC's with
unit capacities above 225 Mg/day. A comparison of the 1991 NSPS and the
proposed NSPS emission limits for these pollutants is shown in table 2.

Table 2.--Comparison of the Proposed NSPS (Subpart Eb) and the 1991 NSPS (Subpart Ea)
----------------------------------------------------------------------------------------------------------------
NSPS emission limit^{a
------------------------------------------------------------------------------
Pollutant or parameter Proposed NSPS (subpart Eb) 1991 NSPS (subpart Ea)
------------------------------------------------------------------------------
MWC plants >35 Mg/day^{b MWC's >225 Mg/day^{c
----------------------------------------------------------------------------------------------------------------
Dioxins/furans................... 0.20 ng/dscm toxic equivalence or 13 ng/ 30 ng/dscm, total mass
dscm total mass. (equivalent to about 0.50 ng/
dscm toxic equivalence).
SO2.............................. 30 ppmv or 80-percent reduction^{d.......... 30 ppmv or 80-percent reduction^{d.
HCl.............................. 25 ppmv or 95-percent reduction^{d.......... 25 ppmv or 95-percent reduction.^{d
PM............................... 15 mg/dscm................................ 34 mg/dscm.
Opacity.......................... 10 percent................................ 10 percent.
Cd............................... 0.010 mg/dscm............................. None.
Pb............................... 0.10 mg/dscm.............................. None.
Hg............................... 0.080 mg/dscm (or 85-percent reduction)^{d.. None.
Nox.............................. 180 ppmv^{e................................. 180 ppmv.
Fly ash/bottom ash fugitive No visible emissions from buildings, ash None.
emissions. transfer points, or ash handling areas.
Siting requirements.............. Siting analysis, materials separation None.
plan, and public meeting requirements.
----------------------------------------------------------------------------------------------------------------
^{aAll emission limits are corrected to 7 percent O2, dry basis.
^{bRefers to aggregate MWC plant capacity.
^{cRefers to MWC unit capacity.
^{dWhichever is less stringent.
^{ePlants >225 Mg/day only.

The MWC operating standards (GCP) contained in today's proposal are
the same as those in the February 11, 1991 NSPS. The training and
certification requirements have changed somewhat. The February 11, 1991
standards require only provisional certification of MWC chief facility
operators and shift supervisors, but today's proposed standards would
require both provisional and then full certification. This change is
being proposed because the full operator certification program is now
widely available. In 1991, the program was not widely available.
Today's proposal also adds a provision to allow provisionally
certified control room operators to stand in for the MWC chief facility
operators or shift supervisors in their temporary absence from the MWC.
Additionally, today's proposal would require all MWC chief facility
operators, shift supervisors, and control room operators to complete
the EPA or a State MWC training course. This training course
requirement was not included in the February 11, 1991 NSPS.

F. Performance Testing and Monitoring Requirements

Information related to the performance testing and monitoring
requirements for MWC acid gases (SO2 and HCl), MWC organics
(dioxin/furan), PM, opacity, MWC operating practices, and NOX has
been published in a previous Federal Register notice (56 FR 5488,
February 11, 1991). These same requirements would be adopted by today's
proposed NSPS and would be extended to apply to all MWC's at plants
with aggregate capacities above 35 Mg/day. Because the proposed NSPS
allows compliance with a dioxin/furan limit either on a TEQ basis or on
a total mass basis, procedures are being proposed for determining
dioxin/furan emissions on a TEQ basis. The mass of each tetra- through
octa- chlorinated dibenzo-p-dioxin and dibenzofuran congener would be
measured by EPA Reference Method 23. Each congener mass would then be
adjusted by the corresponding toxic equivalency factor (TEF; the 1989
NATO international TEF's). Finally, the adjusted congener masses would
be added together to determine dioxins/furans in ng/dscm TEQ.
Furthermore, today's proposal would require both large and small MWC
facilities to conduct annual opacity tests using EPA Reference Method
9. This testing would be in addition to the continuous monitoring of
opacity levels. Also, today's proposal allows small MWC facilities to
conduct less frequent testing for dioxin/furan, HCl, and PM emissions
if the small facility consistently demonstrates compliance. More
specifically, if three consecutive annual compliance tests for an MWC
at a small MWC plant indicate compliance with the emission limit for a
pollutant (i.e., dioxins/furans, PM, or HCl), the MWC would be allowed
to wait 3 years before retesting for the pollutant. If the next test
conducted in the third year shows compliance with the emission limit
for that pollutant, then the facility could again wait 3 years to test
for the pollutant. If noncompliance with the emission limit for the
pollutant occurs, corrective actions would be required to be undertaken
and annual testing would be required to be conducted until 3
consecutive years of compliance with the emission limit is established.
At a minimum, performance tests for dioxins/furans, PM, and HCl would
be required to be performed for each MWC unit at small MWC plants every
3 years. All large MWC plants would continue to be required to conduct
annual compliance tests.
Annual performance tests to determine compliance with the Cd, Pb,
and Hg emission limits would be based on EPA Reference Method 29. The
average emission rates of three or more test runs using this
methodology would be used to determine compliance. The EPA considered
the use of EPA Reference Method 101A for Hg testing; however, based on
available data, the EPA has concluded that Method 29 is a better
measure of Cd, Pb, and Hg emissions than Method 101A and has therefore
proposed Method 29 for testing MWC's.
Also, as discussed above for dioxins/furans, PM, and HCl, if small
plants demonstrate compliance with the Cd, Pb, and Hg emission limits
for 3 consecutive years, they would be allowed to begin testing for
these three pollutants every third year.
The EPA Reference Method 29 is proposed in a separate part of
today's Federal Register. Method 29 is very similar to the method that
has been used by the EPA's Office of Solid Waste to measure metals
emissions from boilers cofiring hazardous waste, commonly referred to
as the EPA multimetals method. The proposed Method 29 is discussed in
section IV.H of this preamble.
Testing and monitoring requirements for NOX at large MWC's are
the same as those contained in the February 11, 1991 Federal Register
notice (56 FR 5488), and are based on use of a CEMS.
Annual performance tests to determine compliance with the proposed
fly ash/bottom ash visible emissions limits would be based on EPA
Reference Method 22 (3-hour continuous visual observation). The limits
would apply at all times and the tests would be conducted during
periods of time when fly ash/bottom ash is transferred from the
combustor or from the air pollution control device to the ash loading
area, and when ash is loaded for transportation or is being transported
onsite.
The data availability requirement for CEMS (SO2, NOX, CO,
and O2 (or CO2)) has been increased from the 1991 NSPS.
Today's proposal would require that valid paired CEMS hourly averages
(i.e., SO2 and O2 (or CO2), NOX and O2 (or
CO2), and CO and O2 (or CO2)) be obtained for 75 percent
of the hours per day for 90 percent of the days per calendar quarter
that the affected facility is operated and combusting MSW.

G. Reporting and Recordkeeping Requirements

The MWC NSPS promulgated on February 11, 1991 established reporting
and recordkeeping requirements for MWC organics (dioxins/furans), MWC
metals (PM and opacity), MWC acid gases (SO2 and HCl), operating
practices (CO, load, flue gas temperature, and operator training/
certification) and NoX. These reporting and recordkeeping
requirements are discussed in the February 11, 1991 Federal Register
notice (56 FR 5488). These same reporting and recordkeeping
requirements would be adopted under the proposed NSPS, with two
exceptions. First, dioxins/furans would be recorded and reported on
either a total mass basis or a TEQ basis. Second, if small MWC's meet
the criteria allowing them to conduct performance tests for dioxins/
furans, PM, and HCl every third year, they would submit a simplified
annual report for those years in which testing was not conducted.
Today's proposal also would add reporting and recordkeeping
requirements for Cd, Pb, and Hg. The proposed standards would require
that initial and annual compliance reports be submitted for Cd, Pb, and
Hg for MWC's at plants with aggregate capacities above 35 Mg/day. If
small MWC's meet the criteria allowing them to conduct performance
tests for Cd, Pb, or Hg every third year, they would be allowed to
submit a simplified annual report for those years when a full
compliance test was not required. The proposed NSPS would also require
that the amount of activated carbon injected for Hg control at small
and large plants be recorded during MWC operation.
Initial and annual compliance reports for fly ash/bottom ash
visible emissions testing would be required under today's proposal for
both small and large plants.
Additionally, today's proposal would require that the siting
analysis, materials separation plan, and summary of responses to public
comments be submitted to the State. Refer to section V.D of this
preamble for a discussion of these proposed requirements.
Records of all data, including results of emission tests and
compliance reports, would be maintained for 5 years following the date
of submission of the data.

III. Impacts of the Proposed Standards

The EPA projects that about 72 new MWC plants with a total MSW
combustion capacity of about 17.6 million Mg/yr will begin construction
by the year 2000. Of those 72 plants, 48 are projected to be large
plants and 24 are projected to be small plants. The proposed subpart Eb
NSPS would cover both the small and large plants, while the 1991
subpart Ea NSPS covers only large plants. This section describes the
impacts (i.e., air, water, solid waste, energy, control cost, and
economic impacts) of the proposed NSPS. The impacts of the proposed
rule are provided in two forms. First, the incremental impacts of the
proposed NSPS over the 1991 subpart Ea NSPS are presented. Second, the
impacts of the proposed NSPS over a pre-1989 baseline (i.e., a baseline
prior to the effective date of the subpart Ea NSPS) are presented. A
summary of these impacts is provided in table 3.

Table 3.--Impacts of the Current Subpart Ea and Proposed Subpart Eb NSPS
------------------------------------------------------------------------
Increment of
proposed NSPS
Parameter over the 1991 1991 NSPS^{a Total^{b
NSPS
------------------------------------------------------------------------
New MWC's subject to
NSPS in the Fifth Year
after Promulgation:
Combustion capacity
(10\6\ Mg/yr)...... 0.8 16.8 17.6
Number of MWC plants 24 48 72
Cost (1990 Dollars):
Capital cost
($10\6\)........... 156 613 769
Annualized cost
($10\6\/yr)........ 43 157 200
Average cost
increase ($/Mg MSW
combusted)......... 1.95 11.55 13.50
Annual Emissions
Reduction (Mg/yr):
SO2................. 3,000 35,000 38,000
HCl................. 4,000 46,000 50,000
PM.................. 800 5,700 6,500
Cd.................. 1 9 10
Pb.................. 17 140 157
Hg.................. 18 9 27
NOX................. 200 10,300 10,500
Total dioxins/furans
(kg/yr)^{c........... 1 28 29
Dioxin/furan TEQ (g/
yr)^{d............... 17 467 484
------------------------------------------------------------------------
^{aThe impacts are based on a pre-1989 baseline (i.e., a baseline prior to
the effective date of the subpart Ea NSPS.
^{bThe total impacts are calculated by adding the incremental impacts of
the proposed NSPS (subpart Eb) to the impacts of the 1991 NSPS
(subpart Ea). These impacts would be equivalent to the total impacts
of the proposed NSPS over a pre-1989 baseline.
^{ckg/yr=kilograms per year.
^{dg/yr=grams per year.

In addition, a summary of economic impacts (e.g., household,
community, and business impacts) is presented that provides projected
economic burdens resulting from the combination of the 1991 subpart Ea
NSPS and the proposed subpart Eb NSPS.
The cost estimates provided in this section are in 1990 dollars,
and include costs for emission control and compliance testing. The
estimates do not include costs for such things as permitting and
enforcement. For further information on the impacts of the proposed
NSPS, refer to the document entitled ``Economic Impact Analysis for
Proposed Emission Standards and Guidelines for Municipal Waste
Combustors'' that is included in the list of items under SUPPLEMENTARY
INFORMATION at the beginning of this preamble.

A. Incremental Impacts of the Proposed NSPS over the 1991 NSPS

The following is a discussion of the incremental air, water and
solid waste, energy, and cost impacts of the proposed NSPS over the
impacts of the 1991 subpart Ea NSPS.
1. Air Impacts
The air emission reductions discussed below, as well as other
impacts discussed in today's proposal, are nationwide impacts that
would result from full implementation of the NSPS in the fifth year
after adoption. These are incremental impacts of the proposal over the
1991 subpart Ea NSPS.
Under today's proposed standards, nationwide emissions of total
dioxins/furans would be reduced by about 1 kilogram per year (kg/yr),
total mass, over the reductions associated with the 1991 subpart Ea
NSPS. Emissions of dioxins/furans on a TEQ basis would reduced by about
10 grams per year (g/yr). On a nationwide basis, dioxin/furan emissions
would be reduced by about 33 percent over levels under the 1991 subpart
Ea NSPS.
Under the proposed NSPS, nationwide emissions of PM would be
reduced by about 800 megagrams per year (Mg/yr) over the levels
associated with the 1991 subpart Ea NSPS. This represents a nationwide
reduction of about 34 percent over the subpart Ea levels.
Nationwide emissions of Cd and Pb would be reduced by about 1 and
17 Mg/yr, respectively, over the levels associated with the 1991
subpart Ea NSPS. This represents an incremental reduction of about 53
percent for Cd and 81 percent for Pb over subpart Ea NSPS levels.
Nationwide emissions of Hg would be reduced by about 18 Mg/yr over
levels associated with the 1991 subpart Ea NSPS. This represents an
incremental reduction of about 72 percent over subpart Ea NSPS levels.
Nationwide emissions of SO2 and HCl would be reduced by about
3,000 and 4,000 Mg/yr, respectively, over reductions associated with
the 1991 subpart Ea NSPS. Total acid gas emissions would be reduced by
about 58 percent over subpart Ea NSPS levels.
Nationwide emissions of NOX would be reduced by about 200 Mg/
yr, or about 1 percent nationwide, over levels associated with the 1991
subpart Ea NSPS.

2. Water and Solid Waste Impacts

The acid gas/PM and NOX control technologies used as the basis
for today's proposed NSPS are the same technologies used as a basis for
the subpart Ea NSPS. Those technologies were determined to have
negligible water or solid waste impacts, as discussed in the previous
Federal Register notice (56 FR 5488).
In the proposed NSPS, activated carbon injection is the
technological basis for controlling Hg emissions. Activated carbon
injection does not produce a wastewater stream, and it would have a
negligible solid waste impact.
As with the 1991 NSPS, the EPA concludes that MWC ash disposal is
adequately addressed by waste management standards so that
considerations of ash quality do not play a role in this rulemaking.

3. Energy Impacts

The energy impact of applying acid gas/PM controls to small plants
and applying Hg controls to both small and large MWC plants will result
in a total national energy increase of about 27 gigawatt hours per year
(GW-hr/yr) of electricity. No increase in the use of natural gas is
anticipated.
Many of the small plants covered under today's proposal produce
steam that is used to generate electricity for sale. For example, a
typical 100 Mg/day MWC plant would generate about 12 GW-hr/yr of
electricity. Such an MWC would require additional energy to operate
pollution control equipment. The required energy would be about 0.7 GW-
hr/yr of electricity, which has a relatively small impact on energy
generated at the plant (about 6 percent of energy generated).

4. Control Cost Impacts

The EPA estimates the incremental annual social cost of control of
the proposed NSPS over the 1991 subpart Ea NSPS to be about $43 million
per year and the incremental national average cost per unit of waste
combusted to be about $1.95/Mg. The incremental capital cost of control
in the first 5 years of application is estimated to be $156 million
over the cost of the 1991 subpart Ea NSPS.

B. Impacts of the Proposed NSPS Over a Pre-1989 Baseline

The following provides a discussion of the impacts of the proposed
subpart Eb NSPS over a pre-1989 baseline. Since the 1991 subpart Ea
NSPS has been effective for 3 years, the impacts presented below
provide a useful account of the total impact of the NSPS, based on both
the 1991 subpart Ea and proposed subpart Eb standards.

1. Air Impacts

The air emission reductions discussed below are nationwide impacts
that would result from full implementation of the NSPS in the fifth
year after adoption. These are not incremental impacts relative to the
February 11, 1991 NSPS (see section III.A for a description of
incremental impacts).
In combination, today's proposed standards and the 1991 NSPS would
reduce nationwide emissions of dioxins/furans by about 29 kg/yr, total
mass. Emissions of dioxin/furans on a TEQ basis would be reduced by
about 480 g/yr. This represents an overall reduction of about 97
percent compared to baseline dioxins/furans emission levels in the
absence of the 1991 and proposed NSPS.
Under the proposed standards and the 1991 NSPS, nationwide
emissions of PM would be reduced by about 6,500 Mg/yr. This represents
an overall control level of over 80 percent for PM emissions compared
to baseline levels in the absence of the 1991 and proposed NSPS.
Nationwide emissions of Cd and Pb would be reduced by 10 and 157
Mg/yr, respectively. This represents an overall reduction of about 94
percent for Cd emissions and about 98 percent for Pb emissions,
compared to emission levels in the absence of the 1991 and proposed
NSPS.
As a result of the 1991 and proposed NSPS, nationwide Hg emissions
would be reduced by about 27 Mg/yr over baseline levels. This
represents an overall reduction of about 80 percent for Hg emissions
compared to baseline levels in the absence of the 1991 and proposed
NSPS.
Nationwide emissions of SO2 would be reduced by about 38,000
Mg/yr, and nationwide emissions of HCl would be reduced by about 50,000
Mg/yr. The 1991 and proposed NSPS would reduce MWC acid gas emissions
by about 94 percent compared to baseline emission levels.
Nitrogen oxides emissions would be reduced by about 10,500 Mg/yr.
This represents an overall nationwide reduction in NOX emissions
of about 35 percent as compared to levels in the absence of the 1991
and proposed NSPS.

2. Water and Solid Waste Impacts

As discussed in section III.A.2, the technologies used to comply
with both the 1991 subpart Ea and proposed subpart Eb NSPS do not
produce a wastewater stream; therefore, no significant water pollution
impacts are projected to occur. Additionally, the application of these
technologies would result in a negligible solid waste impact.

3. Energy Impacts

As a result of the proposed and 1991 standards, total national
usage of energy is estimated to increase by about 290 GW-hr/yr of
electricity above baseline. No increase in the usage of natural gas is
anticipated.
The majority of the MWC's covered under the proposal produce steam
that is used to generate electricity for sale. Those MWC's would
require energy to operate pollution control equipment, but such energy
requirements have a relatively small impact on energy generated at the
plant (about 4 to 6 percent of total energy generated).

4. Control Cost Impacts

a. National Overview. The EPA estimates the total combined annual
social cost of control of the 1991 NSPS and today's proposed standards
to be about $200 million per year, and the overall national average
cost per unit of waste combusted would be about $13.50/Mg. For
perspective, typical costs incurred in 1990 by the general public for
the collection, transportation, and combustion of MSW and ash disposal
ranged from $22/Mg to over $145/Mg of MSW, averaging about $90/Mg.
Additionally, the EPA estimates the capital cost of control in the
first 5 years of application of the 1991 NSPS and today's proposal to
be $769 million.
b. Control Costs for Typical MWC Plants. The previous section
presented costs of the proposal on a national basis. This section
presents examples of typical costs that would be experienced at both a
large MWC plant and a small MWC plant. These are typical costs.
The costing data presented in this section are provided in the
following formats: capital cost, annualized cost, and cost per Mg of
municipal waste combusted. The costing information is subcategorized by
air pollution control components (i.e., acid gas scrubber, activated
carbon injection application, and NOX control). For perspective,
the estimated cost of combustion units (which includes the cost of GCP)
is also displayed. This costing information has been derived from 1989
background information documents that were used in developing the 1991
NSPS (see SUPPLEMENTARY INFORMATION for more information about these
documents), and is presented in 1987 dollars (the escalation factor for
converting to mid-1990 dollars is 1.111).
From table 3A, it can be noted that the capital cost for control at
a new large MWC plant (730 Mg/day capacity) would be about $14.2
million of which $12.0 million would be for the acid gas control, 2.0
million for NOX control, and less than one million for activated
carbon injection. On an annualized basis, the cost would be about $4.2
million/yr or about $17.50/Mg of waste combusted. This would increase
baseline combustor cost from about $60/Mg combusted to about $77/Mg
combusted. Large MWC plants represent about 95 percent of MWC
combustion capacity.
For a new small MWC plant (90 Mg/day capacity), table 3A shows a
capital cost for control of about $3.14 million of which $3.1 million
would be for the acid gas control system and the remaining for
activated carbon injection. On an annualized basis, the cost would be
about $920,000/yr or about $31/Mg of waste combusted. This would
increase baseline combustor cost from about $60/Mg combusted to about
$91/Mg combusted. Small MWC plants represent about 5 percent of MWC
combustion capacity.

C. Economic Impacts

The following provides a discussion of the total economic impacts
(e.g., household, community, and business impacts) of the proposed and
1991 NSPS over a pre-1989 baseline. As discussed in sections III.A.4
and III.B.4 of this preamble, the proposed subpart Eb standards would
have a small incremental national average cost per unit of waste
combusted ($1.95/Mg) as compared to the combined impact of the 1991
subpart Ea NSPS and the proposed subpart Eb NSPS ($13.50/Mg). Since the
proposed NSPS is based on the same technologies as the 1991 NSPS, and
since the 1991 NSPS has been effective for 3 years, the impacts
presented below provide a useful account of the total economic impacts
of the NSPS, based on both the 1991 and proposed NSPS. In estimating
the economic impacts, the EPA assumed that all new MWC's would have
been built with no more emission control than that mandated by
regulations promulgated before 1991, specifically, 40 CFR part 60,
subparts E and Db. This pre-1991 situation represents the baseline for
estimating regulatory costs; therefore, all cost estimates provided are
the full costs above this baseline.

Table 3A.--Capital and Annualized Costs of Air Pollution Control for Typical New Large and Small MWC Plants^{a
----------------------------------------------------------------------------------------------------------------
Air pollution control device cost^{a
------------------------------------------------------------
Baseline Total
Parameter combustor^{b Acid gas/PM Total APCD combustor
CI^{c NOX cost^{d and APCD
cost
----------------------------------------------------------------------------------------------------------------
New large MWC plant (730 Mg/day MB/WW
with SD/FF, CI, and SNCR)^{e, ^{f, ^{g:
Capital cost ($10^{6).............. 50 12 0.150 2.0 14.2 64.2
Percent of total capital cost
(%)^{h............................ 78 19 0.2 3 22 100
Annualized cost ($10^{6/yr)........ 14.4 3.56 0.091 0.582 4.23 18.6
Average cost increase ($/Mg MSW
combusted)...................... 59.5 14.8 0.37 2.39 17.5 77.05
New small MWC plant (90 Mg/day MOD/SA
with SD/FF and CI)^{i:
Capital cost ($10^{6).............. 5.5 3.1 0.043 0 3.14 8.64
Percent of total capital cost
(%)^{h............................ 64 36 0.5 0 36 100
Annualized cost ($10^{6/yr)........ 1.83 0.91 0.014 0 0.92 2.76
Average cost increase ($/Mg MSW
combusted)...................... 60.5 30.2 0.46 0 30.7 91.2
----------------------------------------------------------------------------------------------------------------
^{aThe costs presented are in 1987 dollars. To calculate mid-1990 dollars, multiply 1987 dollars by a factor of
1.111. Total cost values may not add due to rounding.
^{bCosts for good combustion practices are included in combustor design (no cost).
^{cCI = activated carbon injection.
^{dAPCD = air pollution control device.
^{eMB/WW = mass burn waterwall combustor.
^{fSD/FF = spray dryer and fabric filter.
^{gSNCR = selective noncatalytic reduction.
^{hDoes not add to 100 percent due to rounding.
^{iMOD/SA = modular starved-air combustor.

The overall incremental national average cost per unit of waste
combusted of $13.50/Mg (presented in section III.B.4 of this preamble)
breaks down as follows: $11 for acid gas/PM and metals control; $0.40
for Hg control; $1.80 for NOX control; and $0.35 for testing,
reporting, and recordkeeping. The $1.80 cost for NOX control is
for large MWC plants only, because no small plants will incur NOX
control costs.
The standard will have a wide range of impacts on the price of
combustion services. To study these potential impacts, the EPA first
applied a cost accounting procedure that approximates the one that
would be used by an individual publicly owned MWC. Then, using a 1993
average tipping fee of $57/Mg of MSW combusted (1990 dollars) and
assuming the full cost of meeting acid gas, PM, Hg, and NOX
requirements is passed directly to MWC customers, the EPA found that
the lowest and highest tipping fee increases for the model plants used
in the EPA's economic analysis would be about $11/Mg and $85/Mg,
respectively. The majority of tipping fee increases would be in the
$13/Mg to $18/Mg range. This increase would be equivalent to about
$1.00/month to $1.50/month for a typical household.
The EPA projects that, regardless of how the regulatory costs are
financed, most of the burden will find its way directly or indirectly
to households served by MWC's. Costs that are directly assessed to
households are likely to be in the form of increased collection fees
and/or increased taxes. Indirect household costs are price increases
charged by businesses that similarly are faced with increases in
collection fees and/or taxes. For the 1991 NSPS and the standards being
proposed today, the EPA projects an increase in the average annual
household cost of waste disposal of about $21 for communities that
construct new MWC's. The actual cost per household will depend on local
conditions, including the extent to which recycling and landfilling are
also used within the affected community. Approximately 54 percent of
the total average household cost is a direct cost, thus the annual
direct household cost would be a little over $11. The EPA estimates
that the average annual household cost breaks down to $17 per year for
communities over 250,000 in population, $23 for communities with
populations between 100,000 and 250,000, $29 for communities with
populations between 50,000 and 100,000, and $27 for communities with
populations under 50,000. This range represents 0.04 to 0.09 percent of
household income. The EPA expects that comparatively few communities
under 100,000 will be affected by the standards, because such
communities tend to rely on landfilling.
The adoption of new regulations increases costs for a community and
at some point has the potential to affect abilities to issue bonds. To
address this issue, the EPA used demographic and financial data to
project potential difficulty that might confront communities planning
to construct new MWC's with bond financing. Applying generally accepted
criteria for issuance of revenue and general obligation bonds, the EPA
found that no community, large or small, should experience difficulty
with bond financing as a result of the proposed standards.
To address the issue of cost increases, the EPA identified five
private firms that plan to construct one or more MWC's that will be
subject to the standards. Of the five, four are small (i.e., have less
than $6 million in annual sales). (Firms for which annual sales data
are not available are assumed to be small.) Financial data are
available for only one firm, which is a large firm. Total annual costs
of the 1991 and proposed NSPS as a percentage of sales is less than 1
percent for that firm. Potential tipping fee increases, based on the
full pass-through of emission control costs (i.e., passing all control
costs to consumers via the tipping fee) and an average tipping fee of
$57/Mg (1990 dollars), will average about 28 percent for MWC's owned by
small firms, and about 17 percent for MWC's owned by large firms.
In its analysis of cost, economic, and environmental impacts, the
EPA assumed that the 1991 NSPS and the standards being proposed today
will not cause communities to alter their plans to construct new (or to
use already constructed) MWC plants. Specifically, the EPA is assuming
that its projections of how much MSW will be combusted in the year
2000, and the types and sizes of new combustors that will be used, will
not be effected by the standards being proposed today. However, some
communities, if faced with large compliance costs, may choose to delay
or cancel construction, or to downsize MWC's, or to change combustion
technology. These communities probably would expand landfilling,
recycling, or source-reduction activities. If the standards do cause
some communities to shift away from combustion, the result will be a
general reduction of the cost impacts reported here. However, any such
shifts caused by the standards, and the net economic and environmental
effects of those shifts, are extremely difficult to project. This is in
part due to the fact that environmental regulations for landfills, as
well as landfill site location problems, will be exerting an opposite
influence on communities--causing them to look with more favor on
combustion alternatives.
The EPA has been able to quantify some of the benefits of the
standards. The absence of sufficient exposure-response and valuation
information precludes a comprehensive benefits analysis for many of the
MWC pollutants. The EPA expects partial benefits for reduction of PM
and SO2--primarily benefits from reductions in morbidity and
mortality--to total about $160 million annually. However, recent
evidence suggests the mortality reduction benefits of particulate
matter controls may be higher than is assumed in this analysis.
In conclusion, based on the combined economic impacts analysis of
both the 1991 and proposed NSPS, the EPA expects that no community will
be significantly impacted by the proposed and 1991 NSPS. Since the
incremental impact of the proposal over the 1991 NSPS is only one-
seventh the total combined impact (based on incremental national
average cost per unit of waste combusted), the proposal is expected to
have a very small impact on communities.

IV. Rationale for Proposed Standards for MWC Emissions

This section addresses the legal, technical, and economic basis for
the proposed NSPS. The basis for regulating MWC's, for regulating the
specified pollutants, and for regulating MWC's according to the
specified size categories are discussed. The section also presents the
EPA's approach in establishing the MACT floor and selecting MACT.
Additionally, the section discusses the selected format for the
proposed standards, the proposed performance testing and monitoring
requirements, and the proposed reporting and recordkeeping
requirements.

A. Background

On November 15, 1990, the Act was amended. The amendments added a
new section 129 to the Act, which applies to a range of solid waste
incinerators including MWC's, medical waste incinerators (MWI's),
infectious waste incinerators, and industrial waste incinerators.
Under authority of sections 111 and 129 of the Act of 1990, the EPA
was directed to develop and promulgate MACT-based NSPS for MWC's
according to a specified schedule. At the time of enactment of the Act
as amended in 1990, the EPA had already proposed, under section 111 of
the Act, NSPS based on BDT for all sizes of new MWC's. Section 129 of
the Act of 1990 directed the EPA to promulgate standards based on BDT
under the deadlines imposed in the consent decree in State of New York
et al. versus Reilly (No. 89-1729 D.D.C.), but limited applicability of
the standards to combustors with unit capacities greater than 225 Mg/
day. As a result, the standards, which were proposed in 1989, under
development for promulgation in late 1990 were revised to be applicable
only to these MWC units. The final standards were signed by the
Administrator on January 11, 1991 published in the Federal Register on
February 11, 1991 (56 FR 5488).
Section 129 of the Act also directs the EPA to develop another NSPS
for MWC's that would be based on a more stringent control scenario,
apply to smaller facilities, and cover more pollutants. Specifically,
section 129 directs the EPA to promulgate MACT-based NSPS for MWC units
at MWC plants with capacities to combust less than 225 Mg/day. Section
129 also directs the EPA to develop numerical emission limits for Cd,
Pb, and Hg, to incorporate siting requirements for new units, and to
develop operator training requirements. Additionally, section 129
directs the EPA to develop an opacity limit for air curtain
incinerators firing certain ``clean'' fuels.
Today's proposal complies with all requirements of section 129
described above. This has been done by: (1) Proposing MACT-based NSPS
that cover MWC units at plants with capacities above 35 Mg/day; (2)
proposing numerical emission limits for Cd, Pb, and Hg; (3) proposing
siting requirements for new MWC units; (4) proposing operator training
requirements; and (5) proposing opacity limits for air curtain
incinerators firing specific ``clean'' fuels.
The proposed NSPS are, in effect, replacing the February 11, 1991
subpart Ea NSPS for MWC facilities for which construction,
modification, or reconstruction begins after September 20, 1994,
because the February 11, 1991 subpart Ea NSPS are based on BDT rather
than MACT. The February 11, 1991 subpart Ea NSPS will remain in effect
for facilities for which construction, modification or reconstruction
began after December 20, 1989 but on or before September 20, 1994.
Those existing facilities constructed after December 20, 1989 but
before this proposal would be subject to both the 1991 subpart Ea NSPS
and the subpart Cb guidelines proposed in a separate notice in today's
Federal Register. This dual coverage under both the proposed subpart Cb
and the 1991 subpart Ea is further discussed in the preamble to the
proposed subpart Cb in today's Federal Register notice.

B. Selection of Source Category

The previous MWC NSPS adopted on February 11, 1991 provided the
rationale for the selection of MWC's as a source category to be
regulated (56 FR 5488). Moreover, section 129 of the Act directs the
EPA to issue NSPS for this source category, and thereby confirms the
EPA's earlier decision.
Today's proposed NSPS (subpart Eb) would apply to new MWC's,
defined as those MWC's for which construction, modification, or
reconstruction commenced after September 20, 1994. Municipal waste
combustors for which construction, modification, or reconstruction
commenced on or before September 20, 1994, would be covered by the
subpart Cb emission guidelines proposed in a separate notice in today's
Federal Register.
Also, as required by section 129 of the Act, today's proposed NSPS
would establish opacity limits for certain new air curtain
incinerators, for which construction, modification, or reconstruction
commenced after September 20, 1994. Under the proposed NSPS, air
curtain incinerators that burn only yard wastes, tree trimmings, and
clean untreated lumber would be required to meet an opacity limit and
no other requirements would apply. The proposed standards for these air
curtain incinerators are presented in section VII of this preamble.

C. Modification or Reconstruction of Existing MWC's

The subpart Ea NSPS proposal published in the Federal Register on
December 20, 1989 (54 FR 52251) provided a discussion of the terms and
conditions associated with construction, modification, and
reconstruction for MWC's. One change is being proposed. Previously, the
terms ``modification'' and ``reconstruction'' were defined under
sections 60.14 and 60.15 of subpart A of part 60. Section 129 of the
Act has specified a new definition of ``modified solid waste
incineration unit'' that combines and revises the previous definitions
of ``modification'' and ``reconstruction.'' Specifically, ``modified
solid waste incineration unit'' refers to:
(1) Modifications for which the

* * * cumulative costs of the modifications, over the life of
the unit, exceed 50 per centum of the original cost of the
construction and installation of the unit (not including the cost of
any land purchased in connection with such construction or
installation) updated to current costs * * *.

or (2) modifications involving

* * * a physical change in or change in the method of operation
of the unit which increases the amount of any air pollutant emitted
by the unit for which standards have been established under [section
129] or section 111 * * *.

D. Selection of Designated Pollutants

The previous MWC NSPS proposal published in the Federal Register on
December 20, 1989 (54 FR 52251) provided the rationale for the
selection of ``MWC emissions'' and NOX as designated pollutants
under section 111(b) of the Act. Additionally, section 129 of the Act
specifies that emission limits shall be developed for PM, opacity,
SO2, HCl, NOX, CO, Cd, Pb, Hg, and dioxins/furans. Emission
limits for all but three of these pollutants (Cd, Pb, and Hg) were
established in the February 11, 1991 standards. Section 129 also
requires that siting requirements be established for new MWC's that
will minimize, on a site-specific basis, potential risks to public
health or the environment. Today's proposal responds to these new 1990
Act requirements.
Standards for fugitive MWC fly ash/bottom ash emissions are
proposed today because these emissions contain PM, Cd, Pb, Hg, and
dioxins/furans, which are components of the designated pollutant ``MWC
emissions.''

E. Selection of Affected Facilities

For the proposed NSPS, the affected facility, an MWC facility, is
defined as any setting or equipment chamber or pit used to burn MSW
(including RDF) and extends to MWC fly ash/bottom ash emission points,
including ash storage areas, conveyor transfer points, and ash loading
areas for hauling trucks at the MWC site. This does not extend to ash
handling outside of the MWC property boundary or at ash fill sites.
Municipal waste combustion includes the burning (or pyrolysis) of
MSW in any type of equipment, chamber, or pit, including equipment with
and without heat recovery. Municipal solid waste is defined as either a
mixture or a single-item stream of household, commercial, and/or
institutional discards. This would include discards such as paper,
wood, yard wastes, tree trimmings, plastics, leather, rubber, glass,
metals, and other combustible and noncombustible materials. The MSW
definition includes household discards as well as discards from
institutional and commercial sources, but does not include segregated
industrial process/manufacturing discards or medical waste. The MSW
definition also includes RDF, which is a type of MSW that is shredded
(or pelletized) and classified by size before combustion. However, any
mixtures of medical waste with nonmedical hospital waste or with
household, commercial, or institutional waste is considered to be MSW.
Any mixtures or industrial process/manufacturing discards with
nonprocess industrial waste or with household, commercial, or
institutional waste is considered to be MSW. Minor editing has been
made in the definition of MSW to clarify this point.
Cofired combustors are those that fire MSW with non-MSW fuel such
as coal. Cofired combustors that combust a fuel feed stream comprised,
in aggregate, of equal to or less than 30 percent MSW or RDF (by
weight, based on a 24-hour average) would not be subject to the NSPS
and would be required only to submit an initial notification of
construction and subsequent reports of the amount of MSW and other
fuels combusted. The exclusion of cofired combustors from the NSPS is
consistent with section 129 of the 1990 Act. This exclusion is
unchanged from the February 11, 1991 NSPS.
Air curtain incinerators with unit capacities to combust greater
than 35 Mg/day of MSW are subject to the proposal; however, air curtain
incinerators that combust only tree trimmings, yard wastes, and clean
untreated lumber (these are a subset of MSW) would be subject to an
opacity standard and its associated testing, recordkeeping, and
reporting, which are included in today's proposal, but would not be
subject to any other parts of today's proposal. This exclusion does not
apply to air curtain incinerators that combust other MSW materials.
Additionally, waste-fuel power generation facilities that combust a
single-item waste stream of tires, fuel derived solely from tires, or
used oil would be subject only to an initial notification of
construction and would not be subject to any other provisions in
today's proposal. This exclusion is unchanged from the NSPS promulgated
on February 11, 1991.
The NSPS for MWC's proposed today would apply to MWC units at
plants with capacities above 35 Mg/day. The lower size threshold of 35
Mg/day aggregate plant capacity for controlling MWC emissions under the
proposed NSPS was selected after reviewing the population distributions
of MWI's and MWC's. Most incinerators at medical waste facilities are
smaller incinerators that fire segregated medical waste with general
hospital discards (MSW), and these incinerators would have the
potential to be covered by today's proposal. The population
distribution of MWI's is distinctly different from the population
distribution of traditional MWC plants that are the target of today's
proposal. The existing distribution of MWC's is composed of about 179
plants, with an average plant size of about 600 Mg/day combustion
capacity, with two or three MWC units per plant. Assuming continuous
operation, the potential nationwide combustion capacity of existing
MWC's is about 107,000 Mg/day. The MWI distribution is quite different
and includes about 7,000 combustors with a single combustion unit per
facility and an average unit size of less than 3 Mg/day combustion
capacity. The total U.S. capacity of MWI's is about 20,000 Mg/day. This
population is being addressed under a separate rulemaking. These
population distributions of existing MWC's and MWI's are for existing
units but are considered representative of new unit applications.
Clearly, the MWC population represents a smaller number of
comparatively larger combustors, and MWI's represent a much larger
number of smaller combustors. The lower size cutoff of 35 Mg/day
aggregate plant capacity that is included in today's proposal would
exclude less than 1 percent of the total nationwide combustion capacity
of MWC's and would result in over 99 percent of total MWC capacity
being covered by the standards. The same lower size cutoff of 35 Mg/day
would prevent significant dual coverage under the proposal by excluding
more than 99 percent of MWI units and about 97 percent of nationwide
MWI capacity from today's proposed revisions.
The proposed standards would therefore cover the great majority of
MWC's, but cover only a few of the largest regional MWI's (nine units
at three sites are known to cofire medical waste with MSW and are above
the 35 Mg/day total plant capacity cutoff). The Act of 1990 requires
that regulations for MWI's be developed separately. For these reasons,
it is appropriate that today's proposed standards focus on MWC's and
that a separate regulation focus on MWI's. The NSPS and emission
guidelines for MWI's are scheduled to be proposed in 1995.
Those MWC's at plants with aggregate capacities below 35 Mg/day
would not be subject to the emission limits or any other emission
control requirements under today's proposal. However, MWC plants with
aggregate capacities greater than 25 Mg/day and less than or equal to
35 Mg/day would be required to provide a one-time notification of
construction, which would include their location, planned startup date,
the types of fuels that will be combusted, and aggregate plant capacity
and supporting information including calculations used to determine
plant capacity. This one-time report would allow the EPA or State
agency to enforce the lower size cutoff for applicability to the
proposed standards. Plants with aggregate capacities of 25 Mg/day or
below would not be subject to any provisions under this proposal.
The proposed standards for MWC's are subdivided into two
subcategories of air emissions requirements: The first for MWC's
located at MWC plants with aggregate capacities to combust more than 35
Mg/day but less than or equal to 225 Mg/day of MSW (referred to as
small MWC plants), and the second for MWC's located at MWC plants with
aggregate capacities to combust greater than 225 Mg/day of MSW
(referred to as large MWC plants). The 225 Mg/day dividing point was
established because the population of plants with aggregate capacities
equal to or below 225 Mg/day contains many modular MWC's, and there are
concerns about how applicable technologies such as selective
noncatalytic reduction (SNCR) are to modular MWC's.
The EPA projects that the population of new MWC's at plants with
aggregate capacities above 225 Mg/day will account for about 93 percent
of new combustion capacity, whereas the population of MWC's at plants
with aggregate capacities greater than 35 Mg/day but equal to or less
than 225 Mg/day will account for about 7 percent of new combustion
capacity.

F. Selection of Maximum Achievable Control Technology

The following discussion addresses the EPA's selection of MACT. The
existing technologies for controlling emissions of the designated
pollutants from MWC's are first reviewed, followed by a summary of the
EPA's approach for establishing the MACT floor. Finally, the discussion
presents the EPA's selection of MACT for MWC's.

1. Summary of MWC Control Technologies

The following discussion reviews the existing technologies for
controlling emissions of acid gases, dioxins/furans, PM, Cd, Pb, Hg,
and NOX from MWC's.
a. Acid Gas/PM Control Technologies. Municipal waste combustor acid
gas/PM control is a general term that refers to a group of MWC air
pollution control technology combinations. These combinations control a
wide range of pollutants, such as MWC acid gases (including SO2
and HCl), MWC organics (including dioxins/furans), and PM and metals
(including Cd, Pb, and a number of other metals except Hg). The two
acid gas/PM controls most commonly used in the United States for new
MWC's are: (1) GCP plus dry sorbent injection (DSI) followed by a
fabric filter (FF); and (2) GCP plus a spray dryer (SD) followed by an
FF. Discussions of these two acid gas/PM control systems were presented
in the December 20, 1989 proposal preamble for the 1991 acid gas and PM
NSPS in subpart Ea (54 FR 52251). Control of Cd, Pb, and Hg were not
discussed in detail in the 1989 preamble.
Since 1991, the performance of the acid gas/PM control systems for
removal of Cd, Pb, and Hg has been investigated in more depth. Cadmium
and Pb are volatile at temperatures present in combustion systems, but
condense onto PM at temperatures associated with the operation of most
PM control systems. As a result, the control of Cd and Pb is generally
related to the control of PM emissions. However, because of the
potential for adsorption of these metals onto fine PM that is less
readily collected than larger PM, the control efficiency for these
metals may be lower than that for total PM.
Fabric filter-equipped systems (e.g., DSI/FF's and SD/FF's)
generally have better Cd and Pb control because these devices are
better able to collect fine PM than electrostatic precipitator (ESP)-
equipped systems. For DSI/FF and SD/FF systems, data for controlled Cd
emissions range from 0.001 to 0.010 mg/dscm. Emissions of Pb from MWC's
with these systems range up to 0.10 mg/dscm, but the majority are
generally less than 0.050 mg/dscm.
Although the above technologies are effective at removing Cd, Pb,
and other metals, they do not consistently remove Hg without
integrating some other form of Hg control. A discussion of Hg control
is presented below.
b. Mercury Control Technologies. The EPA estimates that typical
uncontrolled Hg emission levels from MWC's in the United States range
from 0.20 to 1.4 mg/dscm at 7 percent O2. Unlike other metals, Hg
has a high vapor pressure at typical operating temperatures of air
pollution control devices; therefore, collection of Hg by the PM
control device is highly variable. The EPA collected test data from
more than 30 MWC's with various air pollution control device systems
that indicate a wide range of Hg control. High-efficiency PM control,
lower flue gas temperatures in the air pollution control system, and a
sufficient level of carbon in the fly ash facilitate Hg control. Higher
levels of carbon in the fly ash and reduced flue gas temperatures
enhance Hg adsorption onto the carbon, which can then be removed by the
PM control device. To promote Hg adsorption, it is important to operate
the control systems at temperatures less than about 150 to 200 deg.C.
Low flue gas temperature is inherent to acid gas control.
Municipal waste combustors with high combustion efficiency will
have effective carbon burnout and, therefore, will have low fly ash
carbon content. These units may achieve little or no Hg control even
when equipped with acid gas/PM control systems, and the control may be
highly variable even at the same site.
Three techniques of Hg control are currently being used: Activated
carbon injection, sodium sulfide (Na2S) injection, and wet
scrubbing. Activated carbon injection and Na2S injection are used
in conjunction with an acid gas control device. Brief discussions of
these three Hg control technologies and their capabilities are
presented below.
Injection of powdered activated carbon into the flue gas prior to
the acid gas/PM control device has been tested at U.S. MWC's. The
removal mechanism is not fully understood, but it is believed that
activated carbon is a catalyst for the oxidation of elemental Hg to
mercuric oxide and mercuric chloride, which can more readily be
captured in the air pollution control device. This technology has been
applied commercially to MWC's in Europe equipped with SD/ESP's and
during test programs in Europe and Canada to MWC's with SD/FF's and
DSI/FF's. The EPA also recently tested activated carbon injection at
the Stanislaus County MWC in California and the Camden County MWC in
New Jersey. The Stanislaus County MWC is equipped with an SD/FF, and
the Camden County MWC is equipped with an SD/ESP. Test results show Hg
reductions greater than 85 percent when injecting activated carbon.
Another Hg control technology that has been applied to MWC's is
Na2S injection. Sodium sulfide is a crystalline solid that
dissolves in water. The resulting Na2S solution is sprayed into
the flue gas prior to the acid gas/PM control device. The reaction of
Na2S and Hg precipitates solid mercuric sulfide (HgS) that is
collected in the PM control device.
Three MWC's in Sweden, two in Germany, and one in Canada have used
Na2S injection to control Hg emissions. All of these facilities
use DSI/FF systems for acid gas/PM control, and injection of Na2S
occurs prior to the DSI/FF system at flue gas temperatures of 130 to
250 deg.C. In addition, Hg emission tests were conducted at the
Stanislaus County MWC in California while using Na2S injection.
Results from tests at European, Canadian, and U.S. MWC's have shown Hg
removal efficiencies of 40 to 90 percent when using Na2S
injection.
Wet scrubbing is a form of acid gas control that also controls Hg
without use of an add-on Hg control system. This technology has
primarily been used on MWC's in Europe and Japan. Typically, the flue
gas is first directed through an ESP to reduce PM, followed by wet
scrubbing, which involves passing the flue gas through a one- or two-
stage absorber system where the gas stream is saturated with an
alkaline solution. During this process, flue gas temperatures are
reduced to as low as 55 deg.C. The low absorber operating temperature
promotes Hg condensation, resulting in an Hg reduction of greater than
80 percent. The alkaline solution used in the wet scrubbing process,
typically containing calcium hydroxide (Ca(OH)2), reacts with the
acid gas to form salts, which are generally insoluble and may be
removed by sequential clarifying, thickening, and vacuum filtering. The
dewatered salts or sludges are then sent to a landfill. The
disadvantages of wet scrubbing include the quantity of water required,
potential difficulties with waste handling, and undefined performance
at U.S. MWC units firing U.S. MSW streams.
c. Nitrogen Oxides Control Technologies. During combustion,
NOX are formed through oxidation of fuel-bound nitrogen (N2)
contained in MSW, and fixation and oxidation of atmospheric N2.
Emissions of NOX can be controlled using SNCR add-on control
technology that reduces NOX to N2 without the use of
catalysts. Techniques include Thermal DeNOX^{TM, which injects
ammonia into the combustor as a reducing agent; the NOXOUT^{TM
process, which injects urea with chemical additives; and a two-stage
urea/methanol injection process. A discussion of SNCR NOX control
was presented in the December 20, 1989 proposal preamble for the 1991
NSPS for new MWC's (54 FR 52251). The use of SNCR at MWC's results in
NOX emission reductions of about 45 percent.
There are some concerns about the applicability of SNCR to modular
MWC's. The SNCR technology has never been applied to modular MWC's, and
several factors may complicate the use of SNCR and may reduce its
performance level. First, many modular units are batch fed in cycles of
about 6 to 12 minutes per charge (due to small combustor size), which
may cause frequent temperature fluctuations. When the temperature
fluctuates above the required injection temperature window, the
reducing reagent is oxidized to NOX, and NOX emissions can
increase. When the temperature drops below the required range,
unreacted ammonia (NH3) emissions can occur. In addition, the
varying moisture and nonhomogeneous nature of the waste burned can also
result in temperature fluctuations in a small unit. With certain
modifications, it may be possible to accommodate SNCR at new modular
units; however, the NOX reduction performance of an SNCR system on
a modular unit will probably be lower than that for a combustor with
more stable operating temperatures, as occurs at large MWC's.
The EPA requests comment on the applicability of SNCR and other
NOX control techniques to MWC's at small plants. The EPA requests
that comments address the cost, technical performance, and reliability
of application of SNCR or other NOX control techniques
specifically to modular starved-air MWC's and modular excess-air MWC's.
Based on the comments and information received, the EPA will reconsider
requiring NOX control on MWC's at small plants.
The amount of NOX formed varies by combustor type. Three types
of MWC's, mass burn/rotary combustors, fluidized-bed combustors, and
modular/excess-air combustors, are considered ``low NOX''
combustors. Available data show that these types of MWC's consistently
show NOX levels below 150 ppmv without the use of SNCR.

2. MACT Floor and MACT Requirements of the Act

The NSPS promulgated under subpart Ea on February 11, 1991 is based
on BDT. Section 129 requires that the NSPS promulgated under subpart Ea
be reviewed and revised based on MACT. Congress established a minimum
floor for the standards. For new sources, the standard may be no less
stringent than ``the emission control that is achieved in practice by
the best controlled similar unit.'' This is often referred to as the
``MACT floor'' for new sources.
To establish the emission control level achieved by the best
controlled similar unit, the EPA reviewed available MWC emissions test
data associated with all types of combustors and all types of emission
control technologies that are currently being used to control emissions
of SO2, HCl, PM, Pb, Cd, Hg, dioxins/furans, and NOX. The EPA
identified the best controlled unit and reviewed the performance of its
associated control technology. The EPA has concluded that the control
technology used by the best controlled unit is applicable to all types
of combustors (with one exception, as noted below) and achieves the
same level of performance on all combustor types. Thus, there is no
need to subcategorize performance to different classes of similar MWC
units. The EPA determined that the best controlled MWC (i.e., the basis
for the MACT floor) would be an MWC equipped with an SD/FF and SNCR
(large MWC plants only). Based on test data from MWC's equipped with
SD/FF and SNCR (large plants only) control systems, the EPA established
the MACT floor as the emission control level for each pollutant
achieved in practice by the best controlled MWC unit.
The MACT floor defines the minimum level of emission control that
may be considered to be MACT, regardless of cost or other
considerations. However, in requiring control beyond the MACT floor
when determining MACT, the EPA must determine the maximum emission
reduction achievable for new MWC units taking into consideration the
cost of achieving such emission reduction and any non-air-quality
health and environmental impacts and energy requirements. Therefore,
the level of control that represents MACT may be more stringent than
the MACT floor. The following section presents the EPA's rationale for
establishing the MACT floor and MACT for MWC's.

3. MACT Floor and MACT

This section summarizes the MACT floor and presents the EPA's
rationale for establishing MACT for each pollutant for MWC's at both
small and large MWC plants.
In establishing the MACT floor and MACT for each pollutant for
small and large plants, the EPA used principally the data base created
for establishing the NSPS for MWC's proposed in 1989 and promulgated in
1991 under subpart Ea. For a few pollutants in this proposal, the EPA
utilized more recent test data to supplement the 1989 data base.
Because most of the test data used for this proposal are more than 4
years old, and in consideration of the fact that most MWC's retest at
least once per year, the EPA requests submittal of the most recent MWC
emissions test data.
Additionally, the EPA requests comment on which MWC emissions test
data would be the most appropriate basis for judging the performance of
SD/FF's in establishing the MACT floor and MACT for new MWC's. For
example, should the EPA consider test data for only the most recently-
built MWC's (e.g., units that have begun operation since 1990), or
should consideration be made of all operational MWC's, independent of
unit age? Also, if the EPA has multiple emission tests for a given MWC
over its operating history (which is common), should the EPA utilize
the data from all of the emission tests performed for the unit or from
only the most recent emission test, in determining the performance of
the unit? The EPA also requests comment on suggestions of analytical
methods to use for analysis of the data (e.g., analytical methods that
could be used to address emissions variability, including methods for
analyzing variable data collected over multiple years for one MWC and
methods of adjusting the emissions data to account for variability).
The appropriate treatment of variability will be related to the format
chosen for the standards (see discussion of alternative formats below).
Based on the new data submitted and on the final choice of which
test data and what analytical methods to use, the EPA may promulgate
final emission limits that are more or less stringent than those
proposed today.
a. Summary of the MACT floor. This proposal determines the MACT
floor for new units based on performance of the best control
technology. Under the proposal, emission control level achieved in
practice by an MWC equipped with the best emission control technology
(i.e., an SD/FF and SNCR (large MWC plants only)) represents the MACT
floor for each pollutant (see table 4).

Table 4.--MACT Floor Emission Levels for New MWC's
------------------------------------------------------------------------
Pollutant MACT floor emission level^{a,b
------------------------------------------------------------------------
SO2............. 30 ppmv or 80-percent reduction.
HCl............. 25 ppmv or 95-percent reduction.
Pb.............. 0.10 mg/dscm.
Cd.............. 0.010 mg/dscm.
PM.............. 15 mg/dscm.
Hg.............. 0.65 mg/dscm.
Dioxins/furans.. 20 ng/dscm total mass or about 0.40 ng/dscm TEQ.
NOX............. 180 ppmv (large MWC plants) Uncontrolled (small MWC
plants).
------------------------------------------------------------------------
^{aAll emission levels are corrected to 7 percent O2, dry basis.
^{bMost of the MACT floor requirements for large MWC plants are more
stringent than the 1991 subpart Ea NSPS (see table 2).

The MACT floor for new sources (best control) could be constructed
in a number of different ways including a technology basis (this
proposal), a permit basis, or an emission data basis. For example,
under the permit basis the most stringent MWC operating permit
limitation might determine the floor. Other approaches are also
possible. The different approaches would result in noticeably different
MACT floor performance levels. The EPA specifically requests comment on
what approach is most appropriate and the rationale for that approach.
Based on the EPA's review of comments received on this issue, as well
as reanalysis of the data submitted, the MACT floor for the promulgated
NSPS may be noticeably higher or lower than the floor included in the
proposal.
b. MACT for Sulfur Dioxide. Uncontrolled SO2 emission levels
at both small and large MWC plants are, on average, 160 ppmv. The best
emission control system for controlling SO2 emissions is an SD/FF.
The EPA's analysis of test data from existing MWC's with SD/FF systems
indicates that an SO2 emission level of either 30 ppmv or an 80-
percent reduction of SO2 emissions can be continuously achieved
over a 24-hour block averaging period. Therefore, the MACT floor for
SO2 emissions is either 30 ppmv or 80-percent reduction, whichever
is less stringent. The proposed MACT standard for SO2 for MWC's at
both small and large MWC plants is the MACT floor level of 30 ppmv or
80-percent reduction, whichever is less stringent.
c. MACT for Hydrogen Chloride. Uncontrolled HCl emission levels at
both small and large MWC plants are, on average, 500 ppmv. The best
emission control system for controlling HCl emissions is an SD/FF. The
EPA's analysis of test data from existing MWC's with SD/FF systems
indicates that an HCl emission level of either 25 ppmv or a 95-percent
reduction in HCl emissions can be achieved. Compliance with the HCl
limit is determined by an annual stack test rather than CEMS, so there
is no CEMS data averaging period associated with this level of
performance. Based on the EPA's analysis, the MACT floor for HCl
emissions is either 25 ppmv or 95-percent reduction, whichever is less
stringent. The proposed MACT standard for HCl for MWC's at both small
and large MWC plants is the MACT floor level of either 25 ppmv or 95-
percent reduction, whichever is less stringent.
d. MACT for Particulate Matter. Uncontrolled PM emission levels at
small and large MWC plants are, on average, 1,500 and 3,700 mg/dscm,
respectively. The best emission control system for controlling PM
emissions is an SD/FF. The EPA's analysis of recent test data has shown
that SD/FF systems can continuously achieve a PM emission level of 15
mg/dscm, which represents greater than 99-percent reduction. Therefore,
the MACT floor for PM emissions is 15 mg/dscm. The proposed MACT
standard for PM for MWC's at both small and large MWC plants is the
MACT floor level of 15 mg/dscm.
e. MACT for Cadmium. Uncontrolled Cd emission levels at both small
and large MWC plants are, on average, 1.2 mg/dscm. The best emission
control system for controlling Cd emissions is an SD/FF. The EPA's
analysis of test data from existing MWC's with SD/FF systems indicates
that these systems can continuously achieve a Cd emission level of
0.010 mg/dscm, which represents greater than 99-percent reduction.
Therefore, the MACT floor for Cd emissions is 0.010 mg/dscm. The
proposed MACT standard for Cd for MWC's at both small and large MWC
plants is the MACT floor level of 0.010 mg/dscm.
f. MACT for Lead. Uncontrolled Pb emission levels at both small and
large MWC plants are, on average, 25 mg/dscm. The best emission control
system for controlling Pb emissions is an SD/FF. The EPA's analysis of
test data from existing MWC's with modern SD/FF systems indicates that
these systems can continuously achieve a Pb emission level of 0.10 mg/
dscm, which represents greater than 99-percent reduction. Therefore,
the MACT floor for Pb emissions is 0.10 mg/dscm. The proposed MACT
standard for Pb for MWC's at both small and large MWC plants is the
MACT floor level of 0.10 mg/dscm.
g. MACT for Mercury. Uncontrolled Hg emission levels at both small
and large MWC plants are, on average, 0.65 mg/dscm. The MACT floor is
based on using an SD/FF. Control of Hg is highly variable, and the
EPA's analysis of recent test data has indicated that the control
efficiency of SD/FF systems for Hg ranges from no control to 50-percent
Hg reduction (i.e., achieving Hg emission levels of 0.33 to 0.65 mg/
dscm). Therefore, the MACT floor for Hg is 0.65 mg/dscm.
As discussed in section IV.F.1.b of this preamble, the EPA has
determined that Hg control is based on three variables: Lower flue gas
temperatures in the air pollution control system, high-efficiency PM
control (e.g., based on use of an FF or ESP), and a sufficient level of
carbon in the fly ash (i.e., based on use of activated carbon
injection). Recent testing programs at the MWC plants in Stanislaus
County, California, and Camden County, New Jersey, have demonstrated
that the combination of an SD/FF or SD/ESP system, activated carbon
injection, and low flue gas temperature at the PM control device inlet
can achieve high Hg control efficiency. The EPA's analysis of this test
data has indicated that MWC's equipped with this combination of control
technologies could continuously achieve an Hg emission level of either
less than 0.080 mg/dscm, corrected to 7 percent O2, or an 85-
percent reduction in Hg emissions. Data from individual test runs show
occasional spikes of high inlet Hg emissions due to the variability in
the waste feed composition. In cases where Hg levels are temporarily
elevated, a 0.080 mg/dscm level may not be consistently achievable;
however, activated carbon injection could achieve an 85-percent
reduction during such episodes. Based on the data from MWC's using
activated carbon injection, Hg control to these levels is achievable by
properly operated systems on all types of MWC's. Since activated carbon
injection is a relatively new technology and has not yet been applied
commercially, the 0.080 mg/dscm or 85-percent reduction Hg emission
level is not part of the MACT floor. The EPA estimates the cost to add
carbon injection to be reasonable, at a cost effectiveness of $1.00/Mg
of MSW combusted. Therefore, the EPA is proposing MACT for Hg for MWC's
at both small and large MWC plants to be more stringent than the MACT
floor, at a level of 0.080 mg/dscm or an 85-percent reduction in Hg
emissions, whichever is least stringent.
The EPA has selected activated carbon injection as the basis for
achieving MACT for Hg, although facilities may use any technology
capable of meeting the proposed standard. Of the three Hg control
technologies discussed in section IV.F.1.b of this preamble, the EPA
has determined that the performance of activated carbon injection is
the best demonstrated of the three Hg control technologies in the
United States.
h. MACT for Dioxins/Furans. Uncontrolled dioxin/furan emission
levels at both small and large MWC plants are, on average, 1,000 ng/
dscm, total mass. The best emission control system for controlling
dioxin/furan emissions is an SD/FF system and GCP. The EPA's analysis
of available test data for dioxin/furan emissions from new MWC's with
SD/FF systems and GCP indicates that dioxin/furan emission levels of
less than 20 ng/dscm total mass are continuously achievable. Therefore,
the MACT floor for dioxins/furans is 20 ng/dscm, which represents a 98-
percent reduction.
The EPA has determined that additional dioxin/furan control is
achievable with activated carbon injection, which is the basis for MACT
for Hg, as discussed above. The EPA's analysis of test data from a
recent testing program at an MWC at the Camden County, New Jersey,
facility and other facilities indicates that the injection of activated
carbon into the flue gas of an SD-based scrubbing system provides
additional removal of dioxins/furans (greater than 50 percent
additional control over levels achieved with SD/ESP systems alone). As
such, the EPA believes a dioxin/furan level of approximately 10 ng/dscm
total mass (which represents a 99-percent reduction) is achievable for
MWC's using GCP and equipped with SD/FF's and activated carbon
injection. Because carbon injection is being proposed as part of the
basis for MACT for Hg, the EPA is proposing MACT for dioxins/furans for
MWC's at both small and large MWC plants based on carbon injection. The
EPA is proposing MACT for dioxins/furans on both a TEQ basis and a
total mass basis. Based on the EPA's analysis of an average TEQ ratio,
the 10 ng/dscm total mass emission level translates to 0.16 TEQ.
However, because there is uncertainty about the ratio, the proposed
MACT floor for dioxins/furans on a TEQ basis is 0.20 ng/dscm. Using the
average TEQ ratio, 0.20 ng/dscm TEQ is equivalent to about 13 ng/dscm
total mass dioxins/furans. Therefore, the EPA is proposing MACT for
dioxins/furans for MWC's at both small and large MWC plants at a level
of 0.20 ng/dscm TEQ or 13 ng/dscm total mass. Sources may comply with
either format of the limit.
However, since the activated carbon injection technology does not
have a long-term record of commercial application in the United States
and since the 0.20 ng/dscm TEQ or 13 ng/dscm total mass standard is
restrictive, the EPA is proposing a 3-year optimization schedule for
activated carbon injection applied at initial subpart Eb applications.
All affected facilities commencing construction after September 20,
1994, but on or before September 22, 1997 would be required to meet a
standard of 0.50 ng/dscm TEQ or 30 ng/dscm total mass for the first 3
years following the date of initial startup. Thereafter, the standard
would be 0.20 ng/dscm TEQ or 13 ng/dscm total mass. For all affected
facilities commencing construction after September 22, 1997, the
standard at startup would be 0.20 ng/dscm TEQ or 13 ng/dscm total mass.
Starting in 1994, MWC units with activated carbon injection technology
will be initiating commercial operation. As dioxin/furan data become
available from MWC's operating with carbon injection technology, the
EPA will reconsider the appropriateness of the 3-year optimization
schedule.
i. MACT for Nitrogen Oxides. The average NOX emission level
for MWC's without postcombustion NOX control (at both small and
large MWC plants) is 225 ppmv. The best emission control system for
controlling NOX emissions from MWC's at large MWC plants is SNCR.
The EPA's analysis of test data for existing MWC's (excluding modular
MWC's) equipped with SNCR indicates that an emission level of 180 ppmv
can be continuously achieved. Therefore, the MACT floor for NOX
for MWC's at large MWC plants is 180 ppmv (24-hour averaging period).
As discussed in section IV.F.1.c of this preamble, the addition of
SNCR postcombustion NOX control has not been demonstrated on any
modular MWC, and the performance of such a system on a modular MWC is
in question. Since the performance of an SNCR system on a modular MWC
is in question, postcombustion NOX control is not being considered
for MWC's at small MWC plants; therefore, the MACT floor for NOX
for MWC's at small MWC plants is no control.
The proposed MACT standard for NOX for MWC's at large MWC
plants is the MACT floor level of 180 ppmv. The proposed MACT standard
for NOX for MWC's at small MWC plants is based on no control.
Section IX of this preamble discusses the proposed ``no control''
NOX standard for MWC's at small MWC plants.

G. Selection of Format for the Proposed Standards

The February 11, 1991 NSPS described a format for MWC acid gases
(SO2 and HCl), MWC metals (PM and opacity), MWC organics (dioxins/
furans), MWC operating practices (CO, load, and flue gas temperature at
the PM control device inlet) and NOX, and that same format is
being adopted by today's proposed NSPS except for dioxins/furans. The
selection of the format for the standards for the above pollutants, is
described in previous Federal Register notices (54 FR 52251, December
20, 1989 and 56 FR 5488, February 11, 1991). The specific formats of
the proposed standards for Cd, Pb, and Hg are discussed below. For
dioxins/furans, the revised format is in units of either TEQ or total
mass dioxin/furans.
As required by section 129(a)(4) of the Act, the proposed standards
would establish numerical limitations for Cd, Pb, and Hg. For the
purpose of regulating Cd and Pb, the format selected in the proposed
NSPS for the numerical emission limitations would be numerical
concentration limits (mg/dscm) at 7 percent O2. For the purpose of
regulating Hg, the format selected would be both a numerical
concentration limit (mg/dscm) and an alternative percentage reduction
requirement. The numerical Hg emission limit reflects the emission
level that can be achieved based on activated carbon injection in
combination with SD/FF controls. An alternative Hg percentage reduction
requirement may be met instead of the numerical emission limit because
emissions of Hg can be highly variable and dependent on the Hg input
level. Even at the same MWC, test data show occasional spikes of high
Hg emissions due to variability in the waste feed. In cases where Hg
levels are temporarily elevated, the 0.080 mg/dscm level may not be
consistently achievable; however, the control devices could achieve the
85-percent reduction during such episodes. Therefore, a combination of
a concentration limit and an optional percentage reduction format best
assures the maximum achievable Hg control while accommodating potential
spikes in Hg emission levels.
As discussed above, the proposed standards for SO2, HCl, and
Hg include two formats: (1) a percent reduction format, and (2) an
emission limit (concentration) format. The EPA requests comment on and
test data supporting the appropriateness of promulgating final
standards for SO2, HCl, and Hg which include only the emission
limit format. For each pollutant, the commenter should specify an
appropriate emission limit (without an associated alternative percent
reduction format) and provide rationale for the limit. Based on the
comments received, the EPA may promulgate final standards for SO2,
HCl, and Hg in the form of emission limits that are higher or lower
than the proposed emission limits.
The EPA has proposed emission limits that reflect the performance
levels achieved by MWC's equipped with properly designed, constructed,
and operated air pollution control systems. The proposed standards
would apply during all periods of MWC operation. To comply with the
proposed standards, the air pollution control system would be designed
and operated such that actual emissions are less than the proposed
emission limits. Where continuous monitoring systems are available,
such as for SO2 and NOX, the proposal would require their use
to determine compliance on a continuous basis. For other pollutants, an
annual stack test would be required. The EPA requests comment on
whether continuous monitoring methods exist for any additional
pollutants.
The EPA also seeks comments on alternate formats of the standard
that would encourage optimal control system operation and optimal
performance, thus minimizing emissions. For example, the standard could
provide incentives, such as reduced testing and reporting, for MWC's
that operate well below the emission limit. One approach would be to
structure the standard such that, for an MWC with multiple units, if
all units demonstrated emissions at least 30 percent less than the
limit, then only one of the units would be tested each year. The unit
selected for testing would be rotated such that each unit would be
tested during its rotational cycle (e.g., once every three years, for
an MWC plant with three units).
Another potential regulatory approach to assure optimal performance
would be to supplement the current emission limits (which must be
demonstrated by annual stack tests) with more stringent emission limits
calculated for each pollutant based on long-term average emission
levels. Compliance with this supplemental limit would be determined by
continuous monitoring, where applicable, or by the average of the
annual emissions tests from the current year and one or more preceding
years. The current limits account for variability from one emissions
test to another, whereas the composite average emission limits would
reflect the mean performance level over the life of the plant. This may
be a preferable measure of environmental performance for some of the
pollutants because it is their long term or cumulative emissions that
are of most concern. Other formats of the standard that encourage
optimal performance would also be possible. Comments and suggestions
are requested. Based on the information and comments received, the EPA
may change the form of the rule to include a long term emissions
average, an alternative compliance testing schedule, or other
alternative format to encourage optimal performance of the air
pollution control system.
Additionally, the EPA requests comment and suggestions on specific
work practice requirements or equipment requirements that would assure
optimal operation of the air pollution control system and minimize
emissions. Such operating practices or equipment practices would be
most beneficial for minimizing emissions of those pollutants for which
annual stack testing is the proposed compliance test method. Comments
are specifically requested on work practice standards or equipment
requirements that would minimize dioxin/furan, Hg, Cd, and PM
emissions. Based on the information received, the EPA may require
specific work practices or equipment to supplement the emission limits
included in the final standards.

H. Performance Test Methods and Monitoring Requirements

The NSPS promulgated on February 11, 1991 for MWC's with unit
capacities above 225 Mg/day established performance testing and
monitoring requirements for MWC acid gases (SO2 and HCl), MWC
metals (PM and opacity), MWC organics (dioxins/furans), MWC operating
practices (CO, load, and flue gas temperature), and NOX. These
testing and monitoring requirements are described in the NSPS
promulgated on February 11, 1991 (56 FR 5488). These same testing and
monitoring requirements will apply to MWC's at all size plants under
today's proposed NSPS, except that: (1) Procedures are being proposed
for determining dioxin/furan emissions on a TEQ basis; (2) continuous
monitoring of NOX is not required at small plants; (3) provisions
have been incorporated to allow compliance testing every third year for
dioxins/furans, PM, and HCl at small plants that pass their compliance
test for 3 years in a row; and (4) annual opacity tests using EPA
Reference Method 9 (in combination with continuous monitoring of
opacity level) would be required for both large and small MWC plants.
Furthermore, today's proposal includes new data availability
requirements for CEMs. Today's proposal requires that valid paired CEMs
hourly averages (i.e., SO2 and O2 (or CO2), NOX and
O2 (or CO2), and CO and O2 (or CO2)) be obtained
for 75 percent of the hours per day for 90 percent of the days per
calendar quarter that the MWC is operating and combusting MSW.
Because the proposed NSPS allows compliance with a dioxin/furan
limit either on a TEQ basis or on a total mass basis, procedures are
being proposed for determining dioxin/furan emissions on a TEQ basis.
For measuring dioxins/furans, on a TEQ basis, the mass of each dioxin/
furan tetra- through octa- congener would be measured by EPA Reference
Method 23. Then, each congener mass would be adjusted by the
corresponding TEF's, which are listed in the proposed NSPS. Finally,
the adjusted congener masses would be added together to determine
dioxins/furans in terms of nanograms per dry standard cubic meter TEQ.
Under the proposed standards, if three consecutive annual
compliance tests for an MWC at a small MWC plant indicate compliance
with the emission limit for a pollutant (i.e., dioxins/furans, PM, or
HCl), the MWC would be allowed to wait 3 years before retesting for the
pollutant. If the next test conducted in the third year shows
compliance with the emission limit for the pollutant, then the facility
could again wait 3 years to wait for the pollutant. If noncompliance
with the emission limit for the pollutant occurs, corrective actions
would be required to be undertaken and annual testing would be required
to be conducted until 3 consecutive years of compliance with the
emission limit established. At a minimum, performance tests for
dioxins/furans, PM, and HCl must be performed for each MWC at a small
MWC plant every 3 years. This provision is included to minimize costs
for small plants, while still retaining periodic testing to ensure
compliance.
Testing and monitoring requirements are being proposed today to
ensure control of Cd, Pb, and Hg emissions. For Cd, Pb, and Hg, an
initial performance test would be required for MWC's at small and large
plants to determine compliance with the proposed emission limits. The
performance test for Cd, Pb, and Hg would be conducted in accordance
with EPA Reference Method 29. The number and location of sampling
points would be determined using EPA Reference Method 1, and flue gas
analysis would be performed using EPA Reference Method 3. All
performance tests would consist of a minimum of three test runs
conducted under representative full load operating conditions. The
average Cd, Pb, and Hg emission rates of three test runs or more would
be used to determine compliance.
Also, as discussed above for dioxins/furans, PM, and HCl, if small
plants demonstrate compliance with the Cd, Pb, and Hg emission limits
for 3 consecutive years, they would be allowed to begin testing for
these three pollutants every third year. At a minimum, performance
tests for Cd, Pb, and Hg would be required to be conducted by small MWC
plants every 3 years. Large plants would be required to test for Cd,
Pb, and Hg annually. These annual testing requirements are consistent
with those for other pollutants, and MWC plants can reduce testing
expenses by testing for multiple pollutants during the same test
period.
Studies conducted by the EPA have shown EPA Reference Method 29 to
be a more reliable method for measuring Hg from MWC's than EPA
Reference Method 101A. Recent refinements have been made to Method
101A, but the EPA has concluded that Method 29 remains a superior
method.
In a separate notice in today's Federal Register, EPA Reference
Method 29 is being proposed for determining emissions of Hg and other
metals from MWC's, MWI's, and power plants. Method 29 consists of a
particulate filter followed in series by two nitric acid/hydrogen
peroxide (HNO3/H2O2) impingers and two acidified
potassium permangenate (KMnO4/H2SO4) impingers. The
method is identical to the EPA's Office of Solid Waste multimetals
method, except that Method 29 requires filtration and analysis of the
impinger solution collected in the KMnO4/H2SO4
impingers. These filtration and analysis requirements are being added
to the method for quality assurance purposes to protect against the
loss of Hg in the manganese oxide (MnO2) precipitate that can form
in this solution. This additional step will result in similar sample
preparation and analysis requirements for EPA Reference Methods 29 and
101A.
The EPA does not believe that addition of the filtration and
analysis step will change the achievable Hg emission rates for MWC's
and MWI's. Because of the significant amount of chlorine in MWC and MWI
flue gas, most of the Hg in these flue gases occurs as water-soluble
ionic Hg. As a result, use of Method 29 collects most of the Hg in
these flue gases on the filter and in the HNO3/H2O2
impingers, with the remainder collected in the KMnO4/
H2SO4 impingers. Flue gases emitted from processes having
lower chlorine levels and/or higher sulfur levels (e.g., coal-fired
power plants) have a higher fraction of their Hg emissions present as
water-insoluble elemental Hg that is collected in the KMnO4/
H2SO4 impingers.
In testing conducted by the EPA at an MWC during which Method 101A
KMnO4/H2SO4 impinger solutions were filtered and the
filters analyzed (with Method 101A, all of the Hg in the flue gas is
collected by the KMnO4/H2SO4 impingers), results showed
that less than 3 percent of the total Hg collected by the sampling
train was associated with precipitated MnO2. Based on review of
analytical procedures used with multimetal trail samples collected
during several other EPA-sponsored test programs, the EPA believes the
potential loss of Hg in precipitated MnO2 during these tests was
less than 3 percent (during these tests, the KMnO4/H2SO4
impingers were shaken prior to removal of a representative analytical
sample and, thus, a portion of any precipitated MnO2 was likely to
have been included in the analytical sample).
Because the analytical filter makes only a negligible difference in
the Hg test results for MWC's and because it is desirable to use a
uniform Hg test method for all source categories, the EPA is proposing
that the full Method 29 test procedures (including the analytical
filter analysis) be used for measuring Hg emissions from MWC's.
Overall, the proposed guidelines would require that CEMS be used as
the compliance test method for those pollutants for which CEMS are
available (i.e., SO2, NOX, CO, CO2 (or O2),
opacity, MWC load level, and air pollution control device temperature).
For those pollutants for which CEMS are not available (i.e., HCl, Hg,
Cd, Pb, PM, and dioxins/furans), the proposed guidelines would require
that stack test methods be used on an annual basis to determine
compliance. Progress continues to be made on the development of new and
improved CEMS. The EPA requests comment on the availability of CEMS to
replace stack testing for any of the pollutants listed above. The EPA
specifically requests comment on the availability, precision, accuracy,
and cost of CEMS for HCl and Hg. Based on the information received, the
EPA will reconsider CEMS requirements and may increase the number of
pollutants monitored by CEMS.

I. Reporting and Recordkeeping Requirements

The proposed standards would require owners and operators of all
affected facilities to submit notifications of construction or
reconstruction, date of anticipated startup, and anticipated date of
demonstration of the continuous emission monitoring system (CEMS) (if
applicable), as required under Sec. 60.7 of subpart A of part 60.
The NSPS promulgated on February 11, 1991 include reporting and
recordkeeping requirements for MWC acid gases, MWC metals (PM and
opacity), MWC organics (dioxins/furan), MWC operating practices, and
NOX. These reporting and recordkeeping requirements are summarized
in the previous Federal Register notice (56 FR 5488, February 11,
1991). Under today's proposed standards, these same reporting and
recordkeeping requirements would apply to MWC's at both small and large
plants with the following four exceptions: (1) Dioxin/furan emissions
would be recorded and reported either in terms of dioxin/furan TEQ or
as total mass of dioxins/furans; (2) monitoring and reporting of
NOX emissions would not be required for small plants because
NOX control is not applicable; (3) if MWC's at small plants have
met the criteria allowing them to conduct compliance tests for dioxin/
furans, PM, or HCl every third year, they would submit a simplified
report for years when a full compliance test was not required; and (4)
both small and large MWC plants would be required to report the results
of annual method 9 opacity tests.
The reporting and recordkeeping requirements in the proposed NSPS
are necessary to inform enforcement personnel of the compliance status
of new MWC's that begin operation.
In addition, the records would provide the data and information
necessary to ensure continued compliance of these MWC's with the
proposed regulation. At the same time, these requirements would not
impose an unreasonable burden on MWC owners or operators. All required
records and all quarterly and annual reports must be maintained for 5
years following the date of such records or submittal of such reports.
All information contained in the records must be open to the public.
Recordkeeping and reporting requirements are being proposed in
today's NSPS for Cd, Pb, and Hg. After the initial performance test has
been completed, the proposed standard would require the submission of
annual compliance reports for Cd, Pb, and Hg for MWC's at both small
and large plants. However, if MWC's at small plants have met the
criteria allowing them to conduct compliance tests for Cd, Pb, or Hg
every third year, they would submit a simplified annual report for
years in which a full compliance test was not required.
The proposed NSPS would require that certain types of records be
maintained. If an activated carbon injection system is used for Hg
control, MWC plants would be required to keep records of the quantity
of activated carbon used for each 8-hour period of MWC operation. These
records would provide documentation that these systems continue to be
operated properly between compliance tests. The proposed NSPS would
also require the submittal of initial and annual compliance reports for
fly ash/bottom ash fugitive emissions testing for MWC's at both small
and large MWC plants.
Additionally, today's proposal would require that the siting
analysis, materials separation plan, and summary of response to public
comment be submitted to the State. Refer to section V.D of this
preamble for a discussion of the proposed reporting requirements.

V. Rationale for the Proposed Standards for Siting Requirements

This section presents the EPA's rationale for establishing the
proposed siting requirements, including a siting analysis, a materials
separation plan, and public meetings.

A. Overview

Under authority of section 129 of the Act, the EPA is proposing
siting requirements for new MWC's. As proposed, the siting requirements
include three major components: (1) A siting analysis, (2) a materials
separation plan, and (3) public meetings with responses to public
comments. These siting requirements would apply only to MWC units at
MWC facilities with aggregate capacities to combust greater than 35 Mg/
day of MSW, for which the initial application for a construction permit
under 40 CFR part 51, subpart I, or part 52 is submitted after the date
of promulgation of the final rule. These siting requirements would not
apply to existing MWC's.

B. Siting Analysis

The following discussion presents the EPA's rationale for proposing
the requirement for sources to prepare a siting analysis, including the
various siting approaches considered and the proposed siting analysis.
1. Siting Analysis Approaches Considered
The EPA considered four approaches in the development of proposed
siting analysis requirements. These approaches are summarized below.
The first approach would require that an environmental assessment
be conducted, patterned on requirements under the National
Environmental Policy Act. This would require an examination of impacts
in all media (i.e., air, water, solid waste, energy, and land use). It
would also require a description of alternatives to the proposed
project including alternative sites, technologies, or design. The
elements of this approach would cover a range of health and
environmental impacts that can be considered in siting an MWC. However,
many of these elements are addressed in current Federal, State, or
local permitting processes or review procedures.
The second approach is patterned after the Resource Conservation
and Recovery Act (RCRA). Requirements for siting hazardous waste
treatment, storage, and disposal facilities. It consists of an
exclusion list with the provision that an MWC cannot be sited in
certain locations (e.g., in a 100-year floodplain or over a high-
quality groundwater resource) unless ``it can be shown to the
satisfaction of EPA'' that no adverse impact will occur.
The third approach would be a regulatory review approach. Under
this approach, the MWC owner or operator would prepare a document
listing all current Federal, State, and local regulatory requirements
and permit conditions that apply to the proposed MWC, along with a
discussion of the equipment, construction practices, operating
practices, and other conditions used to comply with each requirement.
This approach addresses relevant siting issues, and would not require
duplicate analyses of health or environmental impacts that are already
required under other authorities (e.g., New Source Review (NSR) air
permits, National Pollution Discharge Elimination System (NPDES) water
discharge permits, stormwater permits, wetland permits, State solid
waste permits, or local zoning permits).
The fourth approach would establish general siting requirements
patterned after requirements currently in use under the NSR program.
This approach would require an analysis of the impact of the facility,
taking into account other major industrial facilities near the proposal
site, on ambient air quality, visibility, soils, and vegetation. This
approach has already been successfully implemented under the NSR
program. Under this approach, facilities may be able to use analyses
conducted under the NSR program to comply with the NSPS siting
requirements. This approach would also involve public meetings, and the
facility owner or operator would be required to prepare summaries and
comments to the public comments received at the public meetings.
2. Proposed Siting Analysis
The EPA is proposing the fourth approach, as discussed above, as
the basis for the proposed siting analysis. The first three approaches
were considered to either overlap with current requirements or be
overly complex. Under the proposal, MWC owners or operators would be
required to conduct an analysis of the impact of the proposed facility
on ambient air quality, visibility, soils, and vegetation. Furthermore,
this analysis would be required to consider the air quality,
visibility, soils, and vegetation impacts of other major industrial
facilities located near the planned MWC. Consideration of the impacts
of other local facilities would involve an analysis of both background
air quality levels and emissions from other sources in the area prior
to operation of the planned MWC and total air emissions in the area
after addition of the planned MWC due to the incremental impact of the
planned MWC.
The EPA believes that requiring this type of siting analysis would
allow facilities to use the same type of siting analysis for complying
with both NSR and NSPS requirements. The Agency invites comments
regarding the proposed siting analysis, including suggestions of
alternative approaches.

C. Materials Separation/Materials Management Planning

The following discussion presents the EPA's rationale for proposing
the requirement for sources to prepare a materials separation plan.
1. Background
As State and local governments plan for solid waste management, the
EPA has encouraged them to employ the Integrated Solid Waste Management
(ISWM) approach. Through ISWM, communities achieve flexibility by
looking beyond a single solution. In tailoring systems to meet their
unique needs, communities consider all four elements of ISWM:
Reduction, recycling, combustion, and landfilling, as described in
EPA's document entitled ``An Agenda for Action''. In this integrated
approach, systems are designed so that some or all of the four waste
management options are used as a complement to one another to safely
and efficiently manage municipal solid waste. The system is ``custom
designed'' to meet local environmental, economic, and institutional
needs. A key element of integrated waste management is the hierarchy,
which favors source reduction (including reuse) to decrease the volume
and toxicity and increase the useful life of products in order to
reduce the volume and toxicity of waste. Recycling (including
composting) is the preferred waste management option to further reduce
potential risks to human health and the environment, divert waste from
landfills and combustors, conserve energy, and slow the depletion of
nonrenewable natural resources. In implementing source reduction and
recycling, shifting risks from one medium to another (e.g., groundwater
to air) or from one population to another must be avoided. Landfills
and combustors will be necessary for the foreseeable future to handle a
significant portion of wastes, but are lower on the hierarchy because
of the potential risks to human health and the environment and long-
term management costs. This risk potential can be largely minimized
through proper design and management. Integrated waste management can
and should be implemented at a local level to the extent practical, and
is a useful conceptual tool for making management decisions; however,
it must be considered in the context of each community's unique waste
and demographic characteristics. Diversion of solid waste by reducing
the quantity generated and by recycling materials from the waste stream
can effectively reduce the burden on MWC's and landfills.
Waste diversion has become increasingly popular at the local level,
as well as nationally and internationally, as the tool to reduce waste
going to MWC's or landfills. In 1989, the EPA challenged the nation to
reduce and recycle 25 percent of MSW by 1992. The EPA called on all
sectors of our society to voluntarily assume responsibility for helping
to attain this goal. Today, many states have source reduction programs,
including, for example, yard waste composting, fee-for-service
programs, and industrial/commercial waste minimization programs. In
fact, all but eight States have established waste diversion goals.
These goals vary, but generally call for diversion of 20 to 60 percent
of the solid waste stream and are to be attained over the next 5 years.
With EPA encouragement, communities are increasingly using the
``variable rate fee'' approach to charge for waste management services.
This approach fosters waste reduction and recycling because the waste
generators are charged only for the amount of waste they produce that
must be combusted or landfilled. Waste generators can reduce the amount
they pay for services by reducing the amount of waste they produce or
by recycling more materials, thereby diverting materials from MWC's and
landfills.
Across the nation, residents, businesses, and communities are using
a variety of approaches to collect, separate, and otherwise prepare
recovery materials for recycling. These materials may be sorted into
different categories at the point of generation (e.g., residences or
businesses) for separate collection, or they may be collected together
and taken to a regional or community facility for sorting and
processing for recycling.
The collection of recovered materials has grown dramatically and
continues to increase. According to EPA studies, the national recycling
rate was only 9 percent in 1980 and grew to 17 percent by 1992. The EPA
estimates the current national recycling rate at about 22 percent.
Certain States and communities report even higher rates. Across the
nation, materials that formerly were relegated to combustion or
landfilling are being recovered for recycling. Waste reduction and
recycling are increasingly becoming key factors in the sizing, design,
and siting of MWC's and landfills.
Markets for recycled materials are critical to the success of
recycling, and this has been recognized both here and abroad. In the
United States, States have been creative in developing a variety of
nonregulatory approaches to spur markets. These include several
measures to help start new businesses using recovered materials and to
help existing businesses convert to the use of recovered materials,
such as: (1) Information and technical assistance, (2) financing
assistance, (3) direct financial assistance, (4) tax breaks (i.e.,
credits and exemptions), and (5) ``buy recycled'' programs to encourage
the purchase of goods made from recovered materials.
The EPA continues to be instrumental in enhancing markets for goods
from recycled materials. In an effort to position the Federal community
in a leadership role, the EPA is providing guidelines to assist Federal
procurement agencies in buying increasing quantities of goods made from
recovered materials. In October 1993, an Executive Order was signed by
the President of the United States directing Federal agencies to
procure goods made from recovered materials, harnessing the purchasing
power of the Federal community to strengthen markets for these
materials.
There are substantial public and private sector efforts underway
across the nation to foster markets for recycled goods. For example,
the Chicago Board of Trade has recently announced that by late 1994
they will add recyclable plastics and glass to their listing of
commodities. From these efforts, the demand for recovered materials
will grow to complement the increasing supply of materials diverted
from the solid waste stream as more communities implement the ISWM
approach. This diversion will impact the characteristics of the
remaining portion of the waste stream.
2. Proposed Materials Separation Plan
The design of any element of an ISWM system, whether a landfill or
an MWC, must necessarily reflect the impact of the other elements. To
provide for proper sizing and other elements of the landfill or MWC
design, it is important to consider current and projected waste
generation rates and the impact of source reduction and diversion on
the character of the remaining waste stream that serves as the MWC
feedstock. Today's proposal is consistent with and complements the ISWM
approach by providing for an assessment of the impact of materials
separation on municipal waste combustion.
Under today's proposal, prior to applying for a permit to construct
a new MWC, the owner or operator of the MWC would be required to submit
a materials separation plan for public review and comment. Today's
proposal would require the materials separation plan to be applicable
to the area served by the MWC. No rigid performance levels,
specification of separation system design, or designation of materials
to be separated are specified in the proposal.
The proposal allows the materials separation plan to be tailored to
the service area, considered in the design of the new MWC, and reviewed
by the public prior to construction of the MWC. The materials
separation plan may be optimized for the entire service area, so that
certain subareas may have materials separation requirements while other
subareas may not have materials separation requirements. This approach
is fully consistent with EPA's ISWM goals for both MWC's and landfills.
The Agency invites comments regarding the proposed materials
separation plan requirements, including suggestions of alternative
approaches. A definition of ``materials separation plan'' has been
included in the definitions section (Sec. 60.51b) of the proposed NSPS.
The above requirements for a materials separation plan are being
proposed only for new MWC's and are not being proposed for existing
MWC's. The MWC industry has made impressive progress in implementing
materials separation programs at existing MWC's, and this should be
encouraged.

D. Public Meeting and Reporting Requirements

The proposed NSPS requires that the MWC owner or operator make the
materials separation plan available to the public in the service area
where the affected facility is to be constructed. As part of making
this information available to the public, the MWC owner or operator
would be required to distribute a preliminary draft materials
separation plan to all public libraries in the affected service area
and to publish a notification of the public meeting in the principal
newspaper(s) serving the area where the MWC will be sited and where the
waste will be collected. The MWC owner or operator would then be
required to hold a public meeting and accept comments on the
preliminary draft materials separation plan. The public meeting would
be required to be held in the county where the MWC is to be constructed
and would be required to be scheduled 30 days or more after making the
materials separation plan available to the public and publishing the
notification of the public meeting.
At the public meeting, information should be provided that
summarizes what materials are planned for separation, how they will be
separated, what service areas will be included in the plan, and what
level of separation is expected. The information presented at the
meeting should also identify the amount of MSW that is expected to
remain after the separation plan is implemented and identify
alternative disposal methods available for the waste (e.g., local MWC,
local landfill, long-distance transport to an MWC, or long-distance
transport to a landfill). The following hypothetical plan and
discussion serve as an example of the types of information that would
be provided at the meeting. At the public meeting, a plan is proposed
that: (1) Yard waste be collected from specific residential areas using
a curbside collection program, and (2) corrugated paper be collected
from commercial facilities in specific commercial area using dumpster
pickup. The plan is expected to reduce the overall MSW stream by 20
percent, resulting in a residual MSW stream of approximately 400 Mg/day
to be disposed of by either a local MWC or a local landfill.
Although not included as a component of today's proposal, the EPA
encourages the development and public presentation of a supplementary
regional waste management plan. Such plans have already been developed
for many areas. Presentation of a materials management plan at the
initial materials separation public meeting would inform the public
about current regional waste management plans if such plans existed. If
a regional management plan does not exist, the meeting would provide
the opportunity for local public input into the development of a
regional solid waste management plan. A waste management plan would
focus on the full range of options available to manage municipal solid
waste, as exemplified in ISWM. Such a plan could include an analysis of
the current waste generation situation and the range of strategies that
are currently used to deal with municipal solid waste, including the
following examples: current waste generation rates; existing waste
disposal options (e.g., landfills versus MWC's); current source
reduction (e.g., composting and waste disposal fees); and materials
separation and recycling programs. The materials management plan could
consider the adequacy of current strategies to handle projected waste
generation.
Finally, as in the integrated management approach called for under
ISWM, the whole range of strategies available to meet projected waste
disposal needs could be fully examined and considered. This could
include consideration of the role of landfilling, the role of MWC
application, the role of source reduction, and the role of materials
separation and recycling. The materials separation management plan
could outline the expected cost of these alternative strategies to the
public, including the cost per Mg of municipal waste disposed (or the
cost of waste disposal avoided), and their impact in terms of waste
disposal capacity or waste generation avoided.
As mentioned above, a materials management plan is not part of the
proposed siting requirements. The proposed siting requirements include
the development of only a materials separation plan. However, the
materials separation plan and regional materials management plan are
closely related, and public input in their development is encouraged.
The MWC owner or operator would be required to prepare responses to
the comments received at the public meeting. The MWC owner or operator
would be required to make the document summarizing responses to the
public comments available to the public in the service area where the
MWC is to be located, including distribution to all public libraries in
the service area. The MWC owner or operator would then be required to
submit the final draft materials separation plan and the document
summarizing responses to public comments to the State or the EPA, as
applicable, prior to the facility's application for a construction
permit under NSR (40 CFR part 51, subpart I, or part 52, as
applicable). The EPA concluded that the draft materials separation plan
should be submitted during the initial planning process with the
application for a construction permit to be fully consistent with the
EPA's ISWM approach and to ensure that the facility is designed to meet
the materials separation goals of the region or community. Following
application for a NSR construction permit, the public would again have
the opportunity to review and comment on the final draft materials
separation plan at the public meeting that would be held for public
review of the siting analysis, as discussed below. The final materials
separation plan would be submitted with the initial notification of
construction.
The proposed NSPS also requires that, during the period of review
of the materials separation plan and NSR application for a construction
permit, the MWC owner or operator make the MWC siting analysis
available to the public in the service area where the affected facility
is to be constructed. As part of making this information available to
the public, the MWC owner or operator would be required to distribute
the siting analysis to all public libraries in the affected service
area and to publish a notification of the public meeting in the
principal newspaper(s) serving the area where the MWC will be sited and
where the waste will be collected. The MWC owner or operator would then
be required to hold a public meeting and accept comments on the siting
analysis. The public meeting would be required to be held in the county
where the MWC is to be constructed and would be required to be
scheduled 30 days or more after making the siting analysis available to
the public and publishing the notification of the public meeting.
Because the proposed siting analysis is based on the NSR requirements,
the EPA anticipates that if a public meeting is scheduled to address
the environmental impacts analysis required by the NSR program, the
same public meeting could also be used to discuss the proposed siting
analysis. Also, as discussed above, the same public meeting would
address the final draft materials separation plan.
The MWC owner or operator would be required to prepare responses to
the comments received at the public meeting and to make the document
summarizing responses to public comments available to the public in the
service area where the MWC is to be located, including distribution to
all public libraries in the service area. The MWC owner or operator
would be required to submit the siting analysis, the final materials
separation plan, and the document summarizing responses to public
comments on the siting analysis and any additional public comment on
the materials separation plan as part of the facility's initial
notification of construction.
As discussed above, the final materials separation plan is
submitted with the initial notification of construction of the MWC.
Under this proposal, after the final plan is submitted, no subsequent
reporting would be required. However, the EPA is considering requiring
an annual materials separation report. The EPA requests comment on the
usefulness of using a materials separation report to document the
effectiveness of the plan and any changes made to it, and to help
determine if any changes are warranted. Comment is also requested on
appropriate means to ensure that the adopted materials separation plan
is implemented. Based on the comments received, the final regulation
may require submission of annual reports for assessing the performance
of the materials separation plan.

VI. Rationale for the Proposed Standards for Fugitive Fly Ash/Bottom
Ash Emissions

The following discussion addresses the basis for EPA's decision to
regulate fugitive fly ash/bottom ash emissions from MWC facilities. The
available technologies for controlling these fugitive emissions and the
EPA's selection of MACT for these emissions are presented.

A. Background

Fugitive fly ash/bottom ash emissions are emissions of dust from
fly ash and bottom ash handling that are not confined (i.e., emissions
that are not contained within a fully enclosed ash handling system).
The fly ash/bottom ash dust consists of PM and various associated
pollutants adsorbed to the PM such as Cd, Pb, Hg, and organic compounds
(e.g., dioxins/furans). A study of MWC ash handling and storage
facilities at best controlled MWC facilities has shown that such
facilities, when improperly controlled, can be sources of these
pollutants through fugitive fly ash/bottom ash emissions. Therefore,
visible emissions standards for fugitive fly ash/bottom ash emissions
are being proposed to ensure control equipment and operating practices
are implemented to eliminate such emissions.

B. Fugitive Emission Control Techniques

Sources of MWC fugitive fly ash/bottom ash emissions include fly
ash and bottom ash conveyors and conveyor transfer points, storage
facilities (including ash storage bins or piles), and ash loading
facilities for trucks or containers.
Fugitive fly ash/bottom ash emissions from conveyors that are not
already inside enclosed structures can be controlled by totally
enclosing the conveyors. Emissions from conveyor transfer points can be
controlled by totally enclosing the transfer point and ventilating it
to a control device if the transfer point is not inside an enclosed
structure. Alternatively, adequate moisture in the fly ash and bottom
ash can be maintained to control fugitive emissions from conveyors or
transfer points.
Fugitive fly ash/bottom ash emissions from the ash storage
facilities at an MWC plant can be controlled by totally enclosing the
ash storage operations and by ensuring that the fly ash and bottom ash
have an adequate moisture content to prevent dust generation. Chemical
stabilizers and binders may also be used in addition to or in place of
moisture to prevent dust emissions from MWC ash for nearly all the
activities described in this section.
Fugitive fly ash/bottom ash emissions from loading ash into trucks
or containers can be controlled by ensuring an adequate moisture
content of the ash, either by adding extra moisture (water) or by
combining and mixing fly ash with bottom ash that has passed through a
water-filled quench tank. Fugitive fly ash/bottom ash emissions from
the ash loading facility may also be controlled by enclosing the ash
loading facility, fitting the truck bays with doors that can be closed,
and discharging the vent air to a control device.
Fugitive fly ash/bottom ash emissions from moving trucks used for
hauling ash can be controlled by ensuring that the ash is moist and
that the truck or container is properly sealed and covered during
transit. Truck tires can be washed prior to leaving the ash handling
facility to prevent ash from being tracked onto roadways where it can
later become airborne as fugitive fly ash/bottom ash emissions.
Additional emissions control can be achieved by reducing ash spills
during loading and by recovering any spilled ash through sweeping,
vacuuming, or washing before the spilled ash can be tracked out of the
facility.
Data collected at several MWC's indicate that when the control
methods described above are applied in a consistent and conscientious
manner, fugitive fly ash/bottom ash emissions can be controlled so that
no visible emissions are observed from the ash storage facilities, ash
transfer points, ash loading to trucks or containers, and trucks
hauling MWC ash.

C. Proposed Fugitive Emissions Standards

A standard of no visible fugitive fly ash/bottom ash emissions from
ash handling and storage facilities and transfer points is being
proposed and is consistent with the determination that the controls
described above represent MACT. Section 129 of the Act requires that
standards for new sources cannot be less stringent than the control
achieved in practice by the best controlled similar source. The
controls described above are in place at the ash handling and storage
facilities at many MWC's and are the most stringent available controls
for new MWC's.
Therefore, fugitive emission standards are consistent with MACT and
are being proposed. Fugitive fly ash/bottom ash emissions from any MWC
ash storage facility or any ash transfer point at an MWC plant with
aggregate capacity to combust greater than 35 Mg/day of MSW would have
to be controlled so that no visible emissions shall be detected.
The fly ash/bottom ash visible emission standard will be determined
using EPA Reference Method 22 (3-hour continuous visual observation).
Compliance with the visible emissions standards would be determined by
an annual performance test. Reports of initial and annual performance
tests would be required.
Any technology may be used to meet these standards. The fly ash/
bottom ash fugitive emissions standards would apply to ash handling
facilities within the property boundary of the MWC, but would not apply
to offsite transport of ash.

VII. Proposed Standards for Air Curtain Incinerators

Air curtain incinerators operate by forcefully projecting a curtain
of air across the top of an open chamber or pit. The air curtain
reduces emissions during operation by promoting better combustion.
Incinerators of this type are built either above or below ground and
typically have refractory walls and a floor. Section 129 of the Act
exempts air curtain incinerators firing MSW from the definition of
``municipal waste combustion unit'' provided that the air curtain
incinerator burns only tree trimmings, yard wastes, and clean untreated
lumber, and that it complies with an opacity limit that would be
established by the EPA. As clarified under the proposed NSPS,
``untreated lumber'' means that the lumber has not been painted,
pigment-stained, or ``pressure treated.''
Today's proposed NSPS includes opacity limits specifically for air
curtain incinerators that would combust greater than 35 Mg/day of yard
wastes, tree trimmings, or clean untreated lumber. The proposed opacity
limits are 10-percent opacity (6-minute average), except that a level
of up to 35 percent (6-minute average) would be allowed during the
first 30 minutes of operation of the unit. The proposed opacity limits
are based on levels achieved by well-designed and operated air curtain
incinerators. Compliance with the proposed air curtain incinerator
opacity limits would be demonstrated by conducting an annual compliance
test in accordance with EPA Reference Method 9.
Air curtain incinerators with unit capacities above 35 Mg/day that
burn MSW other than yard wastes, tree trimmings, or clean untreated
lumber are covered by the NSPS for MWC's. Air curtain incinerators with
unit capacities above 35 Mg/day that burn only yard wastes, tree
trimmings, or clean untreated lumber would be subject to the proposed
opacity standard and its associated testing, reporting, and
recordkeeping requirements, but would not be subject to any other parts
of the proposed NSPS.

VIII. Comparison of the Proposal and European Emission Limits for MWC's

Europe is more densely populated than the United States and the
combustion of MSW became increasing common after World War II. Because
European countries have more experience combusting MSW, it is
interesting to compare the emission control requirements for MWC's
located in the Member States of the European Union (EU) to those for
MWC's in the United States. In addition to comparing emission
requirements, the EPA also compared the prevalence of waste combustion
in the United States and the EU.
In general, MSW combustion is more common in the EU than in the
United States. There are 12 members of the EU: Belgium, Denmark,
France, Germany, Great Britain, Greece, Ireland, Italy, Luxembourg, The
Netherlands, Spain, and Portugal. The percentage of waste combusted in
many of the EU countries is over 30 percent, with Denmark, Luxembourg,
and the Netherlands, combusting 60, 60, and 40 percent of their waste,
respectively. As a national average for the United States, 16 percent
of the waste generated is combusted. In the Eastern United States,
where the majority of MWC's are located, the rate of waste combustion
is higher, averaging 25 to 30 percent. In the New England region, the
rate of waste combustion approaches 60 percent. Therefore, although the
United States as a whole has a much lower rate of waste combustion than
does the EU, certain regions of the United States have combustion rates
similar to those in the EU.
Factors such as population density, percentage of urbanization,
land availability, and topography/geology influence the method of waste
disposal for a country or a region. In the EU, the majority of the
countries have population densities that range from 200 to 600 people
per square mile and urban population percentages of 60 to 90 percent.
The United States, in comparison, has a much lower average population
density of approximately 70 people per square mile, and the percentage
of the population living in urban areas is approximately 75 percent. In
the Eastern United States, the population density and percentage of
urban population are higher than national levels, at around 200 people
per square mile with over 80 percent of the population living in urban
areas, which is comparable to most of Europe. As noted above, other
factors contribute to the use of MWC technology. For example, in
Florida, the geology is such that in some cases landfilling waste is
not a desirable option. Similarly, the mountainous regions in parts of
Europe restrict the use of landfilling, and the increased use of MWC's
is common.
Regarding regulatory development in the EU, the EU sets uniform
environmental guidelines, and individual EU countries may adopt those
guidelines or more stringent requirements. This is similar to the role
the EPA plays with the individual States. Table 5 presents: (1) The
proposed EPA NSPS for new MWC plants with capacities above 35 and 225
Mg/day and (2) the EU guidelines that apply to new MWC plants with
capacities greater than 72 Mg/day.

Table 5.--Comparison of the EPA's Proposed NSPS and the EU Requirements for New MWC's
----------------------------------------------------------------------------------------------------------------
Proposed EPA NSPS^{b
---------------------------- EU
Pollutant Units^{a (@ 7% O2) Small Large guidelines^{d
plants^{b plants^{c
----------------------------------------------------------------------------------------------------------------
PM................................ mg/dscm........................... 15 15 39
Cd................................ mg/dscm........................... 0.010 0.0101 (^{e)
Pb................................ mg/dscm........................... 0.10 0.10 (^{e)
Hg................................ mg/dscm........................... ^{f0.080 ^{f0.080 (^{e)
Hg and Cd......................... mg/dscm........................... ^{g0.09 ^{g0.09 ^{h0.2
Pb+Cr+Cu+Mn^{i...................... mg/dscm........................... (^{j) (^{j) ^{h6.5
HCl............................... ppmv.............................. ^{k25 ^{k25 ^{kl43
SO2............................... ppmv.............................. ^{m30 ^{m30 ^{h147
NOX............................... ppmv.............................. 500 180 (^{n)
CO................................ ppmv.............................. ^{o100 ^{o100 ^{p112
Dioxins/furans.................... ng/dscm...........................
TEQ............................... 0.20 0.20 (^{n)
Total mass........................ 13 13 (^{n)
----------------------------------------------------------------------------------------------------------------
^{aAll limits are presented on a dry basis, at standard conditions (20 ^{oC, 101 kilopascals) corrected to 7 percent
O2.
^{aApplies to plants that commence construction, modification, or reconstruction after September 20, 1994 and have
capacities greater than 35 Mg/day and less than or equal to 225 Mg/day.
^{cApplies to plants that commence construction, modification, or reconstruction after September 20, 1994 and have
capacities larger than 225 Mg/day.
^{dApplies to all new plants with capacities greater than 72 Mg/day.
^{eNo individual limit specified. See combined limit.
^{fOr 85 percent reduction.
^{gThe proposed NSPS does not include a combined limit for Hg and Cd; however, based on the individual limits, a
combined limit is shown for comparison.
^{hBased on periodic determination.
^{iCr, Cu, and Mn are abbreviations for chromium, copper, and manganese, respectively.
^{jNo combined limit specified. See individual Pb limit.
^{kOr 95-percent reduction. Emissions measured by an annual stack test.
^{lBased on a 7-day rolling average, measured continuously.
^{mOr 80-percent reduction. Limit based on a 24-hour average, measured continuously.
^{nNo limit specified.
^{oFor mass burn/waterwall combustors. Based on a 4-hour average, measured continuously.
^{pBased on an hourly average, measured continuously.

As shown in table 5, the EU guidelines cover many of the same
pollutants as the EPA NSPS proposed in today's notice. There are
differences between the EPA standards and the EU guidelines with regard
to regulatory flexibility for demonstrating compliance, as well as the
test methods used to measure emissions. Factors like these should be
considered when comparing emission requirements. The EPA and EU both
have set levels for PM, HC1, SO2, and CO. For these pollutants,
the allowable emission levels proposed by the EPA are more restrictive
than the EU guidelines. No EU guidelines exist for NOX or dioxins/
furans, and the EU metals emission guidelines are for combined metals
(e.g., Hg+Cd). As shown in table 5, the EPA NSPS for both large and
small plants for Hg and Cd, if combined, are lower than the EU Hg+Cd
guideline.
Some of the EU countries have adopted limits that are more
stringent than the general EU guidelines. For example, The Netherlands
has recently adopted standards for new and existing MWC's that are
considered to be some of the most stringent in the world. For example,
the Dutch Hg limit of 0.065 mg/dscm for new MWC's (corrected to 7
percent O2) is lower than both the EU guideline and the EPA's
proposed Hg standards. The Dutch dioxin/furan limit for new MWC's is
0.13 ng/dscm TEQ. This limit is lower than the EPA's proposed standard
of 0.20 ng/dscm TEQ or 13 ng/dscm total dioxins/furans. The EU has no
dioxin/furan limit.
It is difficult to directly compare the Dutch standards to the EPA
standards or to the performance of U.S. MWC's because the test methods
used in The Netherlands to measure emissions are different from those
used in the United States. Several new MWC plants are currently being
constructed in The Netherlands and are expected to demonstrate
compliance in 1995.
As with some of the EU countries, some of the individual States are
establishing more stringent emissions standards than those in today's
proposed standards. Brief descriptions of the regulations under
consideration in Florida, Minnesota, and New Jersey are presented
below.
The State of Florida has promulgated a regulation that would set an
Hg emission limit of 0.070 mg/dscm (corrected to 7 percent O2), or
an 80-percent Hg reduction, for facilities that install Hg control
equipment (e.g., activated carbon injection) and that are equipped with
acid gas control equipment. This limit must be met by July 1, 1995, and
compliance must be demonstrated annually using EPA Reference Method
101A. For facilities equipped with acid gas control equipment that
choose to control Hg exclusively through the use of an Hg waste
separation program, Hg emissions would be limited to 0.14 mg/dscm after
July 1, 1995 and to 0.070 mg/dscm after July 1, 1997. Compliance must
be demonstrated semiannually using Reference Method 101A. Facilities
not currently equipped with acid gas controls will be required to meet
the proposed Hg emission limits when the facility is required to
demonstrate compliance with the acid gas limits included in the EPA's
proposal. Florida's rulemaking procedures to develop SO2 and HC1
emission limits will be initiated by December 1, 1994, unless the
Federal regulations (today's action) have been proposed by that date.
The State of Minnesota has also promulgated Hg requirements for
MWC's. For mass burn MWC's with acid gas control, the quarterly Hg
emission limit (one three-test run average) is 0.10 mg/dscm (corrected
to 7 percent O2). However, the annual average Hg emissions limit
(average of the four most recent quarterly tests) is 0.060 mg/dscm.
Measurements must be made using EPA Reference Method 29. The Minnesota
requirement also allows MWC's to demonstrate compliance with the
quarterly and annual limits by achieving an alternative 85-percent
reduction in Hg emissions.
Similar to the Florida regulations, the Minnesota regulations
provide less stringent standards for MWC's without acid gas control
until the time that acid gas control is required.
The State of New Jersey will be proposing an Hg standard for MWC's
of 0.028 mg/dscm (corrected to 7 percent O2), which would be
effective as of January 1, 2000, and an interim standard of 0.065 mg/
dscm or an 80-percent reduction, which would be effective as of
December 31, 1995. The 0.028 mg/dscm limit is based on reducing the
uncontrolled Hg emission level (assumed to be 0.70 mg/dscm) by 80
percent through reduction of Hg in the waste burned, and another 80-
percent reduction from Hg in the flue gas. These limits are annual
averages based on quarterly 3-run testing (i.e., a total of 12 runs),
using EPA Reference Method 29.

IX. Miscellaneous

This section addresses the two following issues: (1) The selection
of a ``no control'' limit for NOX for MWC's at small MWC plants,
and (2) the July 14, 1992 remand of the issue of lead-acid vehicle
battery combustion, and (3) a general request for comment on the
proposal.
Regarding the first issue, section 129 of the Act specifies that
standards for MWC's must include emission limits for PM, opacity,
SO2, HC1, NOX, CO, Pb, Cd, Hg, and dioxins/furans. This means
that emission limits for these pollutants must be specified even if the
MACT selected for a subcategory of facilities does not control that
particular pollutant. In particular, under today's proposal, the MACT
floor and MACT for NOX control at small MWC plants is based on no
control (see section IV.F.1.c for additional discussion). Therefore, a
``no control'' emission limit is proposed for NOX emissions from
small MWC plants. The proposed ``no control'' limit for NOX for
small MWC plants is 500 ppmv. This proposed limit is not intended to
result in emissions control, and the proposal does not include any
testing, reporting, or recordkeeping requirements. The EPA expects that
the ``no control'' limit will not be exceeded.
The 500 ppmv limit represents an emission level higher than any of
the test data and allows an adequate margin to accommodate the
variability in NOX emission levels. The EPA requests public
comments on whether it is appropriate to include such a ``no control''
emission limit in the final NSPS or whether such a limit is not
necessary.
Regarding the second issue, on December 20, 1989, the EPA proposed
NSPS and emission guidelines for new and existing MWC's under section
111 of the Act. The proposed NSPS and emission guidelines included a
prohibition on the combustion of lead-acid vehicle batteries in MWC's.
On February 11, 1991, the EPA promulgated standards and guidelines for
new and existing MWC's that did not prohibit the combustion of lead-
acid vehicle batteries. The decision not to prohibit the combustion of
lead-acid vehicle batteries was challenged in the U.S. Court of Appeals
by the NRDC, the State of New York, and the State of Florida. In 1992,
the U.S. Court of Appeals for the District of Columbia Circuit
concluded that the EPA had not adequately explained its decision not to
require a lead acid battery separation as part of the 1991 NSPS and
emission guidelines, when it had included such a requirement in its
proposed rule (State of New York v. Reilly, 969 F.2d 1147, 1153 (D.C.
Cir. 1992)). The EPA is not addressing the lead acid battery issue in
this notice, but will publish a separate notice in the Federal Register
in the near future.
Regarding the third issue, the MWC regulations are complex, and the
EPA expects to receive numerous comments on this proposal. The EPA has
specifically requested comments on items fundamental to the proposal,
including but not limited to the MACT floor, MACT performance levels,
and materials separation plans.

X. Administrative Requirements

This section addresses the following administrative requirements:
public hearing, docket, procedural requirements of the Act, Office of
Management and Budget review, and Regulatory Flexibility Act
compliance.

A. Public Hearing

A public hearing will be held 15 days following proposal. The
public hearing will discuss the proposed standards in accordance with
section 307(d)(5) of the Act. Persons wishing to make oral
presentations at the public hearing should contact the EPA at the
address given in the ADDRESSES section of this preamble. Oral
presentations will be limited to 15 minutes each. Any member of the
public may file a written statement before, during, or within 30 days
after the hearing. Written statements should be mailed to the Air and
Radiation Docket and Information Center at the address given in the
ADDRESSES section of this preamble.
A verbatim transcript of the hearing and written statements will be
available for public inspection and copying during normal working hours
at the EPA's Air and Radiation Docket and Information Center in
Washington, DC (see ADDRESSES section of this preamble).

B. Docket

The docket is an organized and complete file of all the information
submitted to or otherwise considered in the development of this
proposed rulemaking. The principal purposes of the docket are: (1) To
allow interested parties to identify and locate documents so that they
can effectively participate in the rulemaking process; and (2) to serve
as the record in case of judicial review, except for interagency review
material (section 307(d)(7)(A)) of the Act. The docket number for this
rulemaking is A-90-45. Docket No. A-89-08 also includes background
information for this rulemaking that supported the proposal and
promulgation of the subpart Ea NSPS.

C. Clean Air Act Procedural Requirements

The following procedural requirements of the Act are addressed:
administrative listing, periodic review, external participation, and
economic impact assessment.
1. Administrator Listing--Sections 111 and 129 of the Act
As prescribed by section 111 of the Act, establishment of standards
of performance for MWC's is based on the Administrator's determination
(52 FR 25399, July 7, 1987) that these sources contribute significantly
to air pollution that may reasonably be anticipated to endanger public
health or welfare. Additionally, section 129 of the Act of 1990 directs
the Administrator to promulgate revised NSPS for new MWC's.
2. Periodic Review--Sections 111 and 129 of the Act
Sections 111 and 129 of the Act require that the regulation be
reviewed not later than 5 years following the initial promulgation. At
that time and at 5-year intervals thereafter, the Administrator shall
review the regulation and revise it if necessary. This review will
include an assessment of such factors as the need for integration with
other programs, the existence of alternative methods, enforceability,
improvements in emission control technology, and reporting
requirements.
3. External Participation
In accordance with section 117 of the Act, publication of this
proposal was preceded by consultation with appropriate advisory
committees, independent experts, and Federal departments and agencies.
The Administrator welcomes comments on all aspects of the proposal,
including economic and technological issues.
4. Economic Impact Assessment
Section 317A of the Act requires the EPA to prepare an economic
impact assessment for any NSPS promulgated under section 111(b) of the
Act. An economic impact assessment was prepared for the proposed
standards. In the manner described in sections III, IV, V, and VI of
this preamble regarding the impacts of and rationale for the proposed
standards, the EPA considered all aspects of the economic impact
assessment in proposing the standards. The economic impact assessment
is included in the list of key technical documents at the beginning of
today's notice under SUPPLEMENTARY INFORMATION.

D. Office of Management and Budget Reviews

1. 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. An
Information Collection Request (ICR) document has been prepared by the
EPA (ICR No. 1506.03) and a copy may be obtained from Sandy Farmer,
Information Policy Branch (2136), U.S. Environmental Protection Agency,
401 M Street, SW, Washington, DC 20460 or by calling (202) 260-2740.
This collection of information is estimated to have an average
annual reporting burden of about 0.81 person years per recordkeeper
(MWC facility). Very small MWC plants with capacities between 25 and 35
Mg/day will have a smaller burden. These plants would only be required
to submit reports of notification of construction, anticipated startup
date, and actual startup date. Small MWC plants with capacities between
35 and 225 Mg/day would incur the greatest burden as a result of
today's proposed standards. The reporting and recordkeeping burden for
these plants would include initial and annual testing and reporting of
emissions of PM, Pb, Cd, Hg, dioxins/furans, and HC1; SO2 and CO
CEMS demonstration and reporting; preparation of a site selection
analysis report, and other requirements.
Send comments regarding the burden estimate or any other aspect of
this collection of information, including suggestions for reducing this
burden, to Chief, Information Policy Branch (2136), U.S. Environmental
Protection Agency, 401 M Street, SW, Washington, DC 20460, and to the
Office of Information and Regulatory Affairs, Office of Management and
Budget, Washington, DC 20503, marked ``Attention: Desk Officer for the
EPA.'' The final rule will address any comments on the information
collection requirements contained in this proposal.
2. Executive Order 12866 Review
Under Executive Order 12866 (58 FR 51735, October 4, 1993), the EPA
must determine whether the regulatory action is ``significant'', and
therefore, subject to the OMB review and the requirements of the
Executive Order. The Order defines ``significant'' regulatory action as
one that is likely to lead to 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,
users 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, the EPA considers
the proposed NSPS not to be a ``significant'' rule because the annual
effect on the economy is expected not to exceed $43 million over the
cost of the existing subpart Ea NSPS. However, the EPA considers this
proposed NSPS to be ``significant'' because of its relationship to the
emission guidelines for MWC's that are being proposed under a separate
notice in today's Federal Register. The proposed emission guidelines
would cost about $450 million/year. As such, this action was submitted
to OMB for review. Changes made in response to OMB suggestions or
recommendations are documented in the public docket for this
rulemaking.
3. Executive Order 12875
Under Executive Order 12875, the EPA is required to consult with
representatives of affected State, local, and tribal governments, and
keep these affected parties informed about the content and effect of
the proposed standards. The following discussion provides a brief
summary of the content, need for, and cost of the proposal, as well as
the actions that the EPA has taken to communicate and consult with the
affected parties.
a. Summary of the Proposed Standards. The proposed NSPS would
establish emission limitations for new MWC units located at MWC plants
with plant capacities to combust greater than 35 Mg/day of MSW. The
proposed standards do not specify which type of air pollution control
equipment must be used at MWC's to meet the proposed emission
limitations. The EPA expects, however, that, as a result of the
proposal, most large MWC plants (plants with greater than 225 Mg/day
capacity) would use scrubbing systems (SD/FF) for dioxins/furans,
metals, and acid gas control and SNCR for NOX control. Small MWC
plants (plants with 35 to 225 Mg/day capacity) would be expected to
install scrubbing systems (SD/FF), but SNCR technology would not be
necessary. Refer to section II of this preamble for a more detailed
discussion of the proposed standards.
b. Need for the Proposed Standards. Under the Act Amendments of
1990, section 129 includes a schedule that requires the EPA to adopt
the standards for large and small MWC plants by the end of 1991 and
1992, respectively. The EPA did not comply with that schedule and is
now under court order to propose the standards by September 1, 1994 and
promulgate the standards by September 1, 1995. As required by section
129, the proposed standards would establish emission limits for MWC
organics (dioxins/furans), MWC metals (Cd, Pb, Hg, PM, and opacity),
MWC acid gases (HCl and SO2), and NOX. See section I of this
preamble for further discussion of the regulatory history and general
goals of the proposed standards.
c. Cost of the Proposal. The national cost of the proposed NSPS
would be about $43 million per year. The subpart Ea NSPS promulgated in
1991 already requires the installation of acid gas/PM control systems;
therefore, the cost of installing acid gas/PM control systems is not
included in the $43 million per year national cost of the proposal (see
section III.B of this preamble for a discussion of national costs based
on a pre-1989 baseline.) However, for perspective, the cost of the
entire air pollution control system (including acid gas/PM control
systems) is provided here. For an individual combustor subject to the
proposed standards, the cost of the air pollution control system will
vary depending on the plant size. The average annualized cost of
control required by the proposed standards for a typical large MWC
plant would be about $3.8 million per year. The average annualized cost
of control of the proposed standards for a typical small MWC plant
would be about $0.84 million per year. Tipping fees at combustors
currently average about $57/Mg of MSW combusted. As a result of the air
pollution control required by the proposal, the tipping fees for new
MWC plants would typically increase by $13 to $18/Mg, with the lower
cost being for large MWC plants and the higher cost being for small MWC
plants. Regarding the impact of the proposed standards directly or
indirectly on households, the EPA projects an increase in the household
cost of waste disposal of about $17 to $29 per year or about $2 per
month for communities that have MWC's. Refer to section III of this
preamble for a more complete summary of the cost and economic impacts
of the proposed NSPS, on both national and plant-specific bases.
d. Communication with Affected Parties. As previously mentioned,
Executive Order 12875 requires the EPA to consult with representatives
of affected State, local, and tribal governments, and prior to
promulgation of final standards, summarize concerns of the governmental
entities and respond to their comments. The EPA has already initiated
consultations with numerous governmental entities including, but not
limited to, the U.S. Conference of Mayors, the National League of
Cities, the National Association of Counties, the Municipal Waste
Management Association, and the Solid Waste Association of North
America. These groups have been informed of the content of the proposal
and the estimated impacts. In drafting the proposal, the EPA has
considered the concerns expressed by these groups, and discussions with
these groups will continue following proposal. Following proposal, the
EPA will mail a copy of this proposal to all owners/operators of MWC's
and their associated local governmental official. The EPA awaits their
comments on the proposal and will respond to their comments.

E. Regulatory Flexibility Act Compliance

Section 605 of the Regulatory Flexibility Act (RFA) of 1980 (5
U.S.C. 601 et seq.) requires Federal agencies to give special
consideration to the impacts of regulations on small entities, which
are small businesses, small organizations, and small governments. The
major purpose of the RFA is to keep paperwork and regulatory
requirements from getting out of proportion to the scale of the
entities being regulated, without compromising the objectives of, in
this case, the Act.
If a regulation is likely to have a significant economic impact on
a substantial number of small entities, the EPA may give special
consideration to those small entities when analyzing regulatory
alternatives and drafting the regulation. In the case at hand, the EPA
considers that a regulation that is likely to affect 20 percent or more
of small entities with MWC's is a regulation that will affect a
substantial number of small entities.
Definitions of small entities are flexible. For analysis of the
regulations being proposed today, the EPA considers a small business in
this industry to be one with gross annual revenue less than $6 million,
and a small government to be one that serves a population less than
50,000. (A typical city of 50,000 generates about 90 Mg/day of MSW.)
Most small governments dispose of their MSW by landfilling and,
therefore, will not be affected by regulation of MWC emissions. In
regard to small organizations such as independent not-for-profit
enterprises, the EPA finds that they have no more than a very minor
involvement with MWC's, and for that reason the EPA has not found it
necessary to study potential direct impacts on small organizations.
Many MWC's exist that range in size up to 35 Mg/day. The EPA
estimates that MWC's under 35 Mg/day in capacity except for MWI's,
which are being regulated in a separate action, contribute a negligible
fraction of total MWC emissions. Many MWC's under 35 Mg/day in
capacity, and a few larger ones, are owned or operated by small
entities. The EPA estimates that considerably fewer than 20 percent of
small-entity MWC's would be affected by the standards being proposed
today were those MWC's to be constructed in the future. The EPA
projects that the relative proportion of MWC's that are small-entity
MWC's combusting less than 35 Mg/day will remain the same in the future
as it is today.
Thus, the number of affected small entities is not expected to be
substantial, and a regulatory flexibility analysis is not required.
Nevertheless, the EPA has conducted an extensive analysis of potential
regulatory impacts on households, small governments, and small
businesses. The analysis is summarized above in the discussion of
regulatory cost and economic impacts. The full analysis is included in
the economic impact assessment in the docket and is listed at the
beginning of today's notice under SUPPLEMENTARY INFORMATION.
On December 20, 1989, the EPA proposed standards for MWC's that
applied to all sizes of MWC's. The proposal had no lower size cutoff.
Small businesses, small governments, and groups representing small-
entity interests commented extensively on the need to lighten the
potential regulatory burden on small entities. Most commenters
suggested a small size cutoff considerably smaller than the one now
being proposed. The most frequently suggested levels were 5 to 11 Mg/
day, 18 Mg/day, 23 Mg/day, and 45 Mg/day. The EPA has used these
suggestions and the information submitted by these commenters, as well
as information from other sources, to fulfill the intent of the RFA.
The EPA has incorporated into the regulation being proposed today
several features that will mitigate, and in most cases eliminate, any
potential, adverse economic impacts on small entities. These features
are as follows:
(1) The regulation will apply only to MWC's with a plant capacity
of greater than 35 Mg/day. This cutoff eliminates from the purview of
the regulation the overwhelming majority of projected new, very small
MWC's (There will be a one-time requirement for MWC plants in the 25 to
35 Mg/day range to report for verification the capacities and locations
of the plants, but this paperwork will impose no economic burden);
(2) The regulation is ``tiered'' so that the stringency (and
therefore potential economic burden) of the emission standards
increases as the size of the MWC plant increases. Plants with
capacities less than or equal to 25 Mg/day are not covered under the
proposed NSPS. Plants with capacities of 25 to 35 Mg/day would have
only the one-time reporting requirement of capacity and location.
Plants with capacities of 35 to 225 Mg/day are not required to control
NOx. Only plants with capacities larger than 225 Mg/day--plants
not often associated with small entities--are subject to a full
complement of rigorous standards; and
(3) The regulation consists predominantly of emission standards, as
opposed to design, equipment, work practice, or operational standards.
Emission standards give MWC owners and operators the freedom to select
the most economical means of compliance with the standards.
Pursuant to the provisions of 5 U.S.C. 605(b), the EPA certifies
that this proposed regulation, if promulgated, will not have a
significant economic impact on a substantial number of small entities,
because the number of small entities affected is not substantial.

List of Subjects in 40 CFR Part 60

Air pollution control, Incorporation by reference,
Intergovernmental relations, Reporting and recordkeeping.

Dated: September 1, 1994.
Jonathan Z. Cannon,
Acting Administrator.
[FR Doc. 94-22344 Filed 9-19-94; 8:45 am]
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