Federal Register, Volume 79 Issue 137 (Thursday, July 17, 2014)

[Federal Register Volume 79, Number 137 (Thursday, July 17, 2014)]
[Proposed Rules]
[Pages 41772-41793]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-16404]

[[Page 41771]]

Vol. 79

Thursday,

No. 137

July 17, 2014

Part III

Environmental Protection Agency

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40 CFR Part 60

Emission Guidelines and Compliance Times for Municipal Solid Waste
Landfills; Proposed Rule

Federal Register / Vol. 79 , No. 137 / Thursday, July 17, 2014 /
Proposed Rules

[[Page 41772]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2014-0451; FRL-9913-51-OAR]
RIN 2060-AS23

Emission Guidelines and Compliance Times for Municipal Solid
Waste Landfills

AGENCY: Environmental Protection Agency.

ACTION: Advanced Notice of Proposed Rulemaking.

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SUMMARY: The purpose of this Advanced Notice of Proposed Rulemaking
(ANPRM) is to request public input on methods to reduce emissions from
existing municipal solid waste (MSW) landfills. The Environmental
Protection Agency (EPA) intends to consider the information received in
response to the ANPRM in evaluating whether additional changes beyond
those in the proposed revisions for new sources are warranted. MSW
landfill emissions are commonly referred to as ``landfill gas'' or
``LFG'' and contain methane, carbon dioxide (CO2), and
nonmethane organic compounds (NMOC). Some existing landfills are
currently subject to control requirements in either the landfill new
source performance standards (NSPS) or the federal or state plans
implementing the landfill emission guidelines; both the NSPS and
emission guidelines were promulgated in 1996. The EPA believes that
these guidelines merit review to determine the potential for additional
reductions in emissions of LFG. Such reductions would reduce air
pollution and the resulting harm to public health and welfare.
Significant changes have occurred in the landfill industry over time,
including changes to the size and number of existing landfills,
industry practices, and gas control methods and technologies. The ANPRM
recognizes changes in the population of landfills and presents
preliminary analysis regarding methods for reducing emissions of LFG.
In determining whether changes to the emission guidelines are
appropriate, the EPA will, in addition to evaluating the effectiveness
of various methods for reducing emissions of LFG, consider the total
methane emission reductions that can be achieved in addition to the
reductions of NMOC emissions. The EPA is also seeking input on whether
it should regulate methane directly. The ANPRM also addresses other
regulatory issues including the definition of LFG treatment systems and
requirements for closed areas of landfills, among other topics.

DATES: Comments. Comments must be received on or before September 15,
2014.

ADDRESSES: Submit your comments, identified by Docket ID Number EPA-HQ-
OAR-2014-0451, by one of the following methods:
Federal eRulemaking Portal: http://www.regulations.gov.
Follow the online instructions for submitting comments.
Email: A-and-R-Docket@epa.gov. Include Docket ID No. EPA-
HQ-OAR-2014-0451 in the subject line of your message.
Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2014-0451.
Mail: Environmental Protection Agency, EPA Docket Center
(EPA/DC), Mailcode 28221T, Attention Docket ID No. EPA-HQ-OAR-2014-
0451, 1200 Pennsylvania Avenue NW., Washington, DC 20460. Please
include a total of two copies. In addition, please mail a copy of your
comments on the information collection provisions to the Office of
Information and Regulatory Affairs, Office of Management and Budget,
Attn: Desk Officer for EPA, 725 17th Street NW., Washington, DC 20503.
Hand/Courier Delivery: EPA Docket Center, Room 3334, EPA
WJC West Building, 1301 Constitution Avenue NW., Washington, DC 20004.
Such deliveries are only accepted during the Docket's normal hours of
operation, and special arrangements should be made for deliveries of
boxed information.
Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2014-0451. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at http://www.regulations.gov, including any personal
information provided, unless the comment includes information claimed
to be confidential business information (CBI) or other information
whose disclosure is restricted by statute.
Do not submit information that you consider to be CBI or otherwise
protected through http://www.regulations.gov or email. Send or deliver
information identified as CBI to only the mail or hand/courier delivery
address listed above, attention: Mr. Roberto Morales, OAQPS Document
Control Officer (Room C404-02), U.S. EPA, Research Triangle Park, NC
27711, Attention Docket ID No. EPA-HQ-OAR-2014-0451. The http://www.regulations.gov Web site is an ``anonymous access'' system, which
means the EPA will not know your identity or contact information unless
you provide it in the body of your comment. If you send an email
comment directly to the EPA without going through http://www.regulations.gov, your email address will be automatically captured
and included as part of the comment that is placed in the public docket
and made available on the Internet. If you submit an electronic
comment, the EPA recommends that you include your name and other
contact information in the body of your comment and with any disk or
CD-ROM you submit. If the EPA cannot read your comment due to technical
difficulties and cannot contact you for clarification, the EPA may not
be able to consider your comment. Electronic files should avoid the use
of special characters, any form of encryption, and be free of any
defects or viruses.
Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
at http://www.regulations.gov or in hard copy at the Air Docket, EPA/
DC, WJC West Building, Room B102, 1301 Constitution Ave. NW.,
Washington, DC. This Docket Facility is open from 8:30 a.m. to 4:30
p.m., Monday through Friday, excluding legal holidays. The telephone
number for the Public Reading Room is (202) 566-1744, and the telephone
number for the Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For information concerning this ANPRM,
contact Ms. Hillary Ward, Fuels and Incineration Group, Sector Policies
and Programs Division, Office of Air Quality Planning and Standards
(OAQPS) (E143-05), Environmental Protection Agency, Research Triangle
Park, NC 27711; telephone number: (919) 541-3154; fax number: (919)
541-0246; email address: ward.hillary@epa.gov.

SUPPLEMENTARY INFORMATION:
Acronyms and Abbreviations. The following acronyms and
abbreviations are used in this document.

ACT Alternative compliance timeline
ANPRM Advanced Notice of Proposed Rulemaking
AR4 IPCC Fourth Assessment Report
ARB Air Resources Board
BMP Best management practice
CAA Clean Air Act
CBI Confidential business information
CFR Code of Federal Regulations
CO2 Carbon dioxide

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CO2e Carbon dioxide equivalent
CRDS Cavity ringdown spectroscopy
DOC Degradable organic carbon
EPA Environmental Protection Agency
FTIR Fourier Transform Infrared
GCCS Gas collection and control system
GHG Greenhouse gas
GHGRP Greenhouse Gas Reporting Program
GWP Global warming potential
HAP Hazardous air pollutants
HOV Higher operating value
IPCC Intergovernmental Panel on Climate Change
IRIS Integrated Risk Information System
LFG Landfill gas
LMOP Landfill Methane Outreach Program
m\3\ Cubic meters
Mg Megagram
Mg/yr Megagram per year
MSW Municipal solid waste
NAAQS National ambient air quality standards
NAICS North American Industry Classification System
NMOC Nonmethane organic compounds
NOX Nitrogen oxides
NSPS New source performance standards
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PM2.5 Fine particulate matter
ppm Parts per million
ppmv Parts per million by volume
PRA Paperwork Reduction Act
RCRA Resource Conservation and Recovery Act
RFA Regulatory Flexibility Act
RPM Radial plume mapping
SEM Surface emissions monitoring
SIP State implementation plan
TDL Tunable diode laser
Tg Teragram
TTN Technology Transfer Network
UMRA Unfunded Mandates Reform Act
VOC Volatile organic compounds

Organization of This Document. The following outline is provided to
aid in locating information in this document.

I. General Information
A. Does this action apply to me?
B. What should I consider as I prepare my comments?
C. Where can I get a copy of this document and other related
information?
II. Background
A. Landfill Gas Emissions and Climate Change
B. What is the EPA's authority for reviewing the emission
guidelines?
C. What is the purpose and scope of this action?
D. Why are we reviewing the emission guidelines?
E. What is the statutory authority for landfill emission
guidelines?
F. What are the landfill emission guidelines and what sources
would be affected by a review of the emission guidelines?
G. How would changes in applicability affect sources currently
subject to subpart WWW?
III. Why is the EPA concerned about air quality effects from MSW
landfills?
A. Background on the MSW Landfill Sector
B. What emissions are associated with existing MSW landfills?
C. What emission reductions are currently being achieved from
MSW landfills?
D. What are the health and welfare effects of LFG emissions?
IV. Topics for Which the EPA is Seeking Input
A. Taking Reductions in Methane Emissions Into Account in
Reviewing the Emission Guidelines
B. Potential Changes to Regulatory Framework for Existing
Sources
C. Emission Reduction Techniques and GCCS Best Management
Practices
D. Alternative Monitoring, Reporting, and Other Requirements
E. Alternative Emission Threshold Determination Techniques
F. Considerations for Implementation at Closed vs. Active
Landfills
G. Implementation Issues
V. Statutory and Executive Order Reviews

I. General Information

A. Does this action apply to me?

This ANPRM addresses existing MSW landfills and associated solid
waste management programs. Potentially affected categories and entities
include those listed in Table 1 of this document.

Table 1--Regulated Entities
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Examples of affected
Category NAICS \a\ facilities
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Industry: Air and water 924110 Solid waste landfills.
resource and solid waste
management.
Industry: Refuse systems--solid 562212 Solid waste landfills.
waste landfills.
State, local and tribal 924110 Administration of air
government agencies. and water resource and
solid waste management
programs.
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\a\ North American Industry Classification System.

This table is not intended to be exhaustive but rather provides a
guide for readers regarding entities likely to be regulated. The EPA is
specifically requesting input on MSW landfills subject to state plans
or federal plan (40 CFR part 62, subpart GGG) that implement the
emission guidelines at 40 CFR part 60, subpart Cc. The EPA will also
take this information into account in determining if additional changes
to the NSPS at 40 CFR part 60, subpart WWW are appropriate. If you have
any questions regarding whether the EPA is seeking input regarding a
particular MSW landfill, contact the person listed in the preceding FOR
FURTHER INFORMATION CONTACT section.

B. What should I consider as I prepare my comments?

1. Submitting CBI
Clearly mark the part or all of the information that you claim to
be CBI. For CBI information in a disk or CD ROM that you mail to the
EPA, mark the outside of the disk or CD ROM as CBI and then identify
electronically within the disk or CD ROM the specific information that
is claimed as CBI. In addition to one complete version of the comment
that includes information claimed as CBI, a copy of the comment that
does not contain the information claimed as CBI must be submitted for
inclusion in the public docket. Information marked as CBI will not be
disclosed except in accordance with procedures set forth in 40 CFR part
2.
Do not submit information that you consider to be CBI or otherwise
protected through http://www.regulations.gov or email. Send or deliver
information identified as CBI to only the following address: Mr.
Roberto Morales, OAQPS Document Control Officer (Room C404-02), U.S.
EPA, Research Triangle Park, NC 27711, Attention Docket ID No. EPA-HQ-
OAR-2014-0451.
If you have any questions about CBI or the procedures for claiming
CBI, please consult the person identified in the FOR FURTHER
INFORMATION CONTACT section.
Make sure to submit your comments by the comment period deadline
identified in the preceding section titled DATES.
2. Docket
The docket number for the review of the municipal solid waste
landfills emission guidelines is Docket ID No.

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EPA-HQ-OAR-2014-0451. Docket ID Nos. EPA-HQ-OAR-2003-0215 and A-88-09
contain supporting information for 40 CFR part 60, subparts Cc and WWW.

C. Where can I get a copy of this document and other related
information?

World Wide Web (WWW). In addition to being available in the docket,
an electronic copy of this ANPRM is available on the Technology
Transfer Network (TTN) Web site. Following signature, the EPA will post
a copy of this document at http://www.epa.gov/ttn/atw/landfill/landflpg.html. The TTN provides information and technology exchange in
various areas of air pollution control.

II. Background

A. Landfill Gas Emissions and Climate Change

In June 2013, President Obama issued a Climate Action Plan
directing the EPA and other federal agencies to take a wide variety of
significant steps to reduce methane emissions. The plan, which
encompassed a wide range of actions and voluntary initiatives,
recognized that methane emissions constitute a significant percentage
of domestic greenhouse gas (GHG) emissions, highlighted reductions in
methane emissions since 1990, and outlined specific actions that could
be taken to achieve additional progress. Specifically, the federal
agencies were instructed to focus on ``assessing current emissions
data, addressing data gaps, identifying technologies and best practices
for reducing emissions, and identifying existing authorities and
incentive-based opportunities to reduce methane emissions.''
The focus on reducing methane emissions reflects the fact that
methane is a potent GHG with a global warming potential (GWP) that is
25 times greater than that of CO2.\1\ Methane has an
atmospheric life of 12 years, and because of its potency as a GHG and
its atmospheric life, reducing methane emissions is one of the best
ways to achieve a near-term beneficial impact in mitigating global
climate change.
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\1\ IPCC Fourth Assessment Report (AR4), 2007. Climate Change
2007: The Physical Science Basis. Contribution of Working Group I to
the Fourth Assessment Report of the Intergovernmental Panel on
Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A.
(eds.)]. IPCC, Geneva, Switzerland, 104 pp.
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In response to the directive in the 2013 Climate Action Plan, the
``Climate Action Plan: Strategy to Reduce Methane Emissions'' (the
Methane Strategy) was released in March 2014. The Methane Strategy
noted that the landfill standards at issue here and voluntary programs
already in place have considerably reduced methane emissions, while
creating jobs and improving public health. With respect to landfills,
the Methane Strategy directs the agency to build upon progress to date
through updates to the EPA's rules for reducing emissions from new,
modified, and reconstructed landfills; to issue an ANPRM to explore
options to address emissions from existing landfills; and to encourage
energy recovery from LFG through voluntary programs.
The EPA has long recognized the climate benefits associated with
reducing methane emissions from landfills. In the 1991 Landfill NSPS
Background Information Document,\2\ the EPA noted that reduction of
methane emissions from MSW landfills is one of the many options
available to reduce global warming. When the EPA promulgated the NSPS
for MSW landfills, which regulates MSW landfill emissions (landfill
gas), in 1996, the EPA noted the climate co-benefit of controlling
methane, which was not as well understood at the time as today (61 FR
9917, March 12, 1996). In 1996, the EPA stated:
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\2\ Air Emissions from Municipal Solid Waste Landfills-
Background Information for Proposed Standards and Guidelines, U.S.
EPA (EPA-450/3-90-011a) (NTIS PB 91-197061) page 2-15.

``An ancillary benefit from regulating air emissions from MSW
landfills is a reduction in the contribution of MSW landfill
emissions to global emissions of methane. Methane is a major
greenhouse gas, and is 20 to 30 times more potent than
CO2 on a molecule-per-molecule basis. There is a general
concern within the scientific community that the increasing
emissions of greenhouse gases could lead to climate change, although
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the rate and magnitude of these changes are uncertain.''

Since 1996, the EPA and the scientific community have gained a
better understanding of GHGs, including methane, and their effects on
climate change and human health and welfare. In 2009, the EPA
Administrator issued the document known as the Endangerment Finding
under CAA section 202(a)(1).\3\ In the Endangerment Finding, which
focused on public health and public welfare impacts within the United
States, the Administrator found that elevated concentrations of GHGs
\4\ in the atmosphere may reasonably be anticipated to endanger the
public health and welfare of current and future generations. In light
of this finding, the EPA has been examining regulatory options for
reducing GHG emissions.
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\3\ Endangerment and Cause or Contribute Findings for Greenhouse
Gases Under Section 202(a) of the Clean Air Act, 74 FR 66496
(December 15, 2009) (Endangerment Finding).
\4\ Carbon dioxide (CO2), methane (CH4),
nitrous oxide (N2O), hydrofluorocarbons (HFCs),
perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).
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The EPA is reviewing the MSW landfills emission guidelines and in
light of the President's Climate Action Plan, the Methane Strategy, and
improvements in the science related to GHG emissions, is exploring
opportunities to achieve additional reductions in emissions, including
methane emissions. The EPA intends to issue a proposed review of the
emission guidelines by March 2015 and take final action on the proposal
by March 2016.
Landfill gas is a collection of air pollutants, including methane
and NMOC. Landfill gas is typically composed of roughly 50-percent
methane, 50-percent CO2, and less than 1 percent NMOC by
volume. The NMOC portion of LFG, although a small amount by volume, can
contain a variety of significant air pollutants. NMOC includes various
organic hazardous air pollutants (HAP) and volatile organic compounds
(VOC). When 40 CFR part 60, subparts Cc and WWW were promulgated in
1996, NMOC was selected as a surrogate for MSW landfill emissions
because NMOC contains the landfill air pollutants that pose more
concern due to their adverse health and welfare effects. Today, there
is a greater emphasis on methane emissions because of their effects on
climate change. Note that in 2012, landfills represented 18.1 percent
of total U.S. methane emissions.\5\ Methane represents 8.7 percent of
all GHG emissions (in CO2e) in the United States.\6\ For
these reasons, the EPA is considering changes to the emission
guidelines that are based on reducing the methane and NMOC components
of LFG. The EPA is seeking input on whether it should regulate methane
directly.
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\5\ Total U.S. methane emissions were just below 600 million Mg
CO2e in 2012. ``Inventory of U.S. Greenhouse Gas
Emissions and Sinks: 1990-2012.'' Available at http://www.epa.gov/climatechange/ghgemissions/gases/ch4.html.
\6\ U.S. EPA. 2012. ``Inventory of U.S. Greenhouse Gas Emissions
and Sinks: 1990-2012. Executive Summary.'' Available at http://www.epa.gov/climatechange/Downloads/ghgemissions/US-GHG-Inventory-2014-Chapter-Executive-Summary.pdf.
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B. What is the EPA's authority for reviewing the emission guidelines?

The EPA is not statutorily obligated to conduct a review of the
emission guidelines, but has the discretionary authority to do so when
circumstances

[[Page 41775]]

indicate that this is appropriate. Based on changes in the landfills
industry and changes in size, ownership, and age of landfills since the
emission guidelines were promulgated in 1996, the EPA has concluded
that it is appropriate to review the landfills emission guidelines at
this time. As part of the data collection efforts for the statutorily
mandated review of the MSW landfills NSPS, the EPA received, and has
since compiled, new information on existing landfills. That
information, together with the information being solicited through this
ANPRM, will allow the EPA to conduct an assessment of the current
practices, emissions and the potential for reductions in emissions. Any
changes to the emission guidelines that might result from this review
will ultimately apply to landfills that accepted waste on or after
November 8, 1987 \7\, and that commenced construction, reconstruction,
or modification prior to publication of proposed revisions to the
landfills NSPS, 40 CFR part 60, subpart XXX, as discussed in further
detail in sections II.F and II.G of this document.
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\7\ This date in 1987 is the date on which permit programs were
established under the Hazardous and Solid Waste Amendments of RCRA.
This date was also selected as the regulatory cutoff in the EG for
landfills no longer receiving wastes because EPA judged States would
be able to identify active facilities as of this date.
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C. What is the purpose and scope of this action?

The purpose of this ANPRM is to request public input on methods to
reduce emissions from existing MSW landfills and to request input on
potential resolutions or clarifications regarding issues that have
arisen during implementation of the existing standards.

D. Why are we reviewing the emission guidelines?

The EPA is considering changes to the emission guidelines for a
number of reasons, including the following: (1) The opportunity to
build on progress to date and achieve additional reductions of LFG and
its components, consistent with the President's Methane Strategy, (2)
changes in size, ownership, and age of landfills as reflected in new
data, (3) new options for demonstrating compliance, and (4) the
completion of efforts regarding implementation issues for which the EPA
previously proposed resolution. The EPA is considering these topics in
its review, as discussed in the following sections.
1. Opportunity To Achieve Additional Reductions From Existing Landfills
The EPA recognizes the opportunity to build on progress to date and
achieve additional reductions of LFG and its components. A subset of
existing landfills are controlled by either the landfill emission
guidelines (40 CFR part 60, subpart Cc) or by the landfill NSPS (40 CFR
part 60, subpart WWW). Controls installed as a result of these
regulations have successfully reduced LFG emissions. Although methane
emissions from landfills in 2012 are 30 percent lower than they were in
1990, methane emissions from landfills continue to be a concern.
Despite these controls installed to date, in 2012, landfills emitted
102.8 teragrams (Tg) (or 102.8 million metric tons) CO2e,
making landfills the third largest source of human-related methane
emissions in the United States. The number of existing landfills
(>1,800) is significantly higher than the number of new landfills (21)
that are projected to open in the next 5 years. Therefore, if there are
cost effective changes for existing landfills, revising these
regulations may realize a great benefit given the number of existing
landfills.
In this ANPRM, the EPA is exploring and requesting input on
approaches that have the potential to achieve additional emission
reductions from MSW landfills. Some of these approaches are adjustments
to the current framework of the landfills regulations, others would
complement the existing framework, and still others would be entirely
outside the current framework. These approaches are presented in
section IV of this document and include potential adjustments to the
design capacity threshold; the NMOC emissions threshold; and the timing
of installing, expanding and removing the gas collection and control
system (GCCS). Approaches also include potential changes to emission
threshold determinations, consideration of best management practices
(BMPs), and new technologies that could improve collection and control
of LFG emissions. The EPA will consider the input and data received on
these approaches during the review of the landfills emission guidelines
and determine whether it is appropriate to revise the emission
guidelines to further reduce LFG emissions from existing landfills.
2. New Data Available Since Emission Guidelines Were Originally
Promulgated in 1996
The EPA collected current data for the statutorily required review
of the landfills NSPS, 40 CFR part 60, subpart WWW. Three sources were
used for that effort: A landfill and LFG energy project database
maintained by EPA's Landfill Methane Outreach Program (LMOP), a
voluntary survey of landfills, and the Greenhouse Gas Reporting Program
(GHGRP). The creation of the landfill dataset, including identification
of the sources of the information contained therein, is detailed in the
docketed memorandum, ``Summary of Landfill Dataset Used in the Cost and
Emission Reduction Analysis of Landfills Regulations. 2014.'' The EPA
used the dataset, which included landfill-specific data such as
landfill open and closure year, landfill design capacity, landfill
design area and landfill depth, to examine the effects of potential
changes to the size and emission thresholds for installing controls.
The dataset also provides information on landfill practices such as
liquids recirculation, waste composition, presence and type of GCCS and
energy recovery projects. The availability of new data on MSW landfills
is discussed in section II.D.2 of this document.
3. New Options for Demonstrating Compliance
The EPA is considering and requesting input on potential options
for demonstrating compliance. For example, the EPA is considering
alternative wellhead monitoring requirements that could include
exclusion or reduced frequency of temperature, oxygen/nitrogen
monitoring requirements and whether such adjustments should be limited
only to landfills that beneficially use LFG or should be available to
all landfills, including small entities. The EPA is considering and
requesting public input on potential approaches to surface emission
monitoring. Approaches include changing the walking pattern that
traverses the landfill, adding an integrated methane concentration
measurement and allowing sampling only when wind is below a certain
speed. These new options for demonstrating compliance are discussed in
section IV.D of this document. The EPA will consider the input and data
received on these approaches during the review of the landfills
emission guidelines with the intent of further reducing LFG emissions
from existing landfills.
4. Concerns Arising From Implementation of Subparts Cc and WWW That the
EPA Plans To Address in a Forthcoming Proposal
The landfill emission guidelines were originally promulgated in
1996. Over time, the EPA has become aware of a

[[Page 41776]]

number of implementation issues associated with the regulatory
requirements and for which landfill owners and operators, as well as
regulators, need clarification. The EPA proposed amendments to the
landfills NSPS and emission guidelines (40 CFR part 60, subpart WWW and
40 CFR part 60, subpart Cc) on May 23, 2002 (67 FR 36475), and
September 8, 2006 (71 FR 53271). Those amendments were never finalized.
The EPA is not taking final action on either the May 23, 2002, or the
September 8, 2006, proposed rules through this ANPRM, but we are
soliciting input on the unresolved implementation issues. These issues
include but are not limited to: LFG treatment, accounting for emissions
from closed areas of landfills, surface monitoring, and corrective
action timelines. Note that the EPA addressed some of these
implementation issues as they apply to new MSW landfills in the Federal
Register document that proposes a new subpart resulting from the EPA's
review of the landfills NSPS. The EPA plans to address amendments and
clarifications resulting from implementation activities as they apply
to subparts Cc and WWW in forthcoming amendments to these subparts. See
section IV.G of this document for details.

E. What is the statutory authority for landfill emission guidelines?

Clean Air Act (CAA) section 111, which Congress enacted as part of
the 1970 CAA Amendments, establishes mechanisms for controlling
emissions of air pollutants from stationary sources. This provision
requires the EPA to promulgate a list of categories of stationary
sources that the Administrator, in his or her judgment, finds ``causes,
or contributes significantly to, air pollution which may reasonably be
anticipated to endanger public health or welfare.'' \8\ The EPA has
listed more than 60 stationary source categories under this provision,
including municipal solid waste landfills.\9\ Once EPA lists a source
category, the EPA must, under CAA section 111(b)(1)(B), establish
``standards of performance'' for emissions of air pollutants from new
sources in the source categories.\10\ These standards are known as new
source performance standards or NSPS, and they are national
requirements that apply directly to the sources subject to them.
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\8\ CAA section 111(b)(1)(A).
\9\ See 40 CFR part 60, subparts Cb through OOOO.
\10\ CAA section 111(b)(1)(B), 111(a)(1).
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When the EPA establishes NSPS for new sources in a particular
source category, the EPA is also required, under CAA section 111(d)(1),
to prescribe regulations for states to submit plans regulating existing
sources in that source category for any air pollutant that, in general,
is not regulated under the CAA section 109 requirements for the
National Ambient Air Quality Standards (NAAQS) or regulated under the
CAA section 112 requirements for HAP. CAA section 111(d)'s mechanism
for regulating existing sources differs from the one that CAA section
111(b) provides for new sources because CAA section 111(d) is
implemented through state plans that establish ``standards of
performance'' for the affected sources and that contain other measures
to implement and enforce those standards.
``Standards of performance'' are defined under CAA section
111(a)(1) as standards for emissions that reflect the emission
limitation achievable from the ``best system of emission reduction,''
considering costs and other factors, that ``the Administrator
determines has been adequately demonstrated.'' CAA section 111(d)(1)
grants states the authority, in applying a standard of performance to
particular sources, to take into account the source's remaining useful
life or other factors.
Under CAA section 111(d), a state must submit its plan to the EPA
for approval, and the EPA must approve the state plan if it is
``satisfactory.'' \11\ If a state does not submit a plan, or if the EPA
does not approve a state's plan, then the EPA must establish a plan for
that state.\12\ Once a state receives the EPA's approval for its plan,
the provisions in the plan become federally enforceable against the
entity responsible for noncompliance, in the same manner as the
provisions of an approved State Implementation Plan (SIP) under CAA
section 110.
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\11\ CAA section 111(d)(2)(A).
\12\ CAA section 111(d)(2)(A).
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The EPA issued regulations implementing CAA section 111(d) in
1975.\13\ These implementing regulations provide that, in promulgating
requirements for sources under CAA section 111(d), the EPA first
develops regulations known as ``emission guidelines,'' which establish
binding requirements that states must address when they develop their
plans.\14\ The implementing regulations also establish timetables for
state and EPA action: States must submit state plans within 9 months of
the EPA's issuance of the guidelines,\15\ and the EPA must take final
action on the state plans within 4 months of the due date for those
plans,\16\ although the EPA has authority to extend those
deadlines.\17\
---------------------------------------------------------------------------

\13\ ``State Plans for the Control of Certain Pollutants From
Existing Facilities,'' 40 FR 53340 (November 17, 1975).
\14\ 40 CFR 60.22. In the 1975 rulemaking, the EPA explained
that it used the term ``emissions guidelines''--instead of emissions
limitations--to make clear that guidelines would not be binding
requirements applicable to the sources, but instead are ``criteria
for judging the adequacy of State plans.'' 40 FR 53343.
\15\ 40 CFR 60.23(a)(1).
\16\ 40 CFR 60.27(b).
\17\ See 40 CFR 60.27(a).
---------------------------------------------------------------------------

Over the last 40 years, under CAA section 111(d), the agency has
regulated four pollutants from five source categories (i.e., sulfuric
acid plants (acid mist), phosphate fertilizer plants (fluorides),
primary aluminum plants (fluorides), Kraft pulp plants (total reduced
sulfur), and municipal solid waste landfills (LFG)).\18\
---------------------------------------------------------------------------

\18\ See ``Phosphate Fertilizer Plants; Final Guideline Document
Availability,'' 42 FR 12022 (March 1, 1977); ``Standards of
Performance for New Stationary Sources; Emission Guideline for
Sulfuric Acid Mist,'' 42 FR 55796 (October 18, 1977); ``Kraft Pulp
Mills, Notice of Availability of Final Guideline Document,'' 44 FR
29828 (May 22, 1979); ``Primary Aluminum Plants; Availability of
Final Guideline Document,'' 45 FR 26294 (April 17, 1980);
``Standards of Performance for New Stationary Sources and Guidelines
for Control of Existing Sources: Municipal Solid Waste Landfills,
Final Rule,'' 61 FR 9905 (March 12, 1996).
---------------------------------------------------------------------------

F. What are the landfill emission guidelines and what sources would be
affected by a review of the emission guidelines?

The Emission Guidelines and Compliance Times for Municipal Solid
Waste Landfills (emission guidelines) are codified at 40 CFR part 60,
subpart Cc. The emission guidelines cross reference many provisions in
the Standards of Performance for Municipal Solid Waste Landfills
(landfills NSPS) (40 CFR part 60, subpart WWW), including control
requirements, operational standards, monitoring provisions, and
reporting and recordkeeping requirements. As a result, many of the
proposed changes to the standards of performance for new,
reconstructed, and modified MSW landfills could affect subpart Cc. A
detailed summary of the current emission guideline requirements appears
in section IV.B.1 of this document.
CAA section 111(d) calls for a partnership between the EPA and
states, as described above. To recap, the EPA establishes source-
category-specific emission guidelines that specify the minimum
requirements for an approvable state plan, including the requisite
level of emission reductions that must be achieved. Each state must

[[Page 41777]]

develop a state plan establishing standards of performance for the
affected sources in the state based on the requirements of the emission
guidelines. The state must submit its state plan to the EPA for
approval. The EPA reviews the state plan to ensure that it meets the
minimum requirements of the emission guidelines, and approves the plan
if it does. If the state does not submit a state plan, or the state
plan is disapproved, the EPA would have the authority to promulgate a
federal plan under CAA section 111(d)(2)(A). MSW landfills constructed,
modified or reconstructed prior to proposal of the revised landfills
NSPS, 40 CFR part 60, subpart XXX that have accepted waste since
November 8, 1987 would be considered ``existing'' and would be affected
by any changes to the emission guidelines resulting from this review.
States with designated facilities would be required to develop (or
revise) and submit a state plan to the EPA within 9 months of
promulgation of any revisions to the emission guidelines unless the EPA
specifies a longer time frame. Any revisions to an existing state plan
and any newly adopted state plan must be established following the
requirements of 40 CFR part 60, subpart B. Those requirements include
making the state plan publically available and providing opportunity
for public discussion. Once the EPA receives a complete state plan or
plan revision and completes its review of that plan or plan revision,
the EPA will propose the plan or plan revision for approval or
disapproval and must take final action to approve or disapprove the
plan or plan revision no later than 4 months after the date the plan or
plan revision was required to be submitted. The EPA will publish state
plan approvals or disapprovals in the Federal Register and will include
an explanation of its decision. The EPA will also revise the existing
federal plan (40 CFR part 62, subpart GGG) to incorporate any changes
and other requirements that the EPA promulgates as a result of its
review of the emission guidelines. The revised federal plan will apply
in states which have not received approval of any necessary revised
state plan until such time as the revised state plan is approved.

G. How would changes in applicability affect sources currently subject
to subpart WWW?

If the EPA were to revise the landfills emission guidelines to
increase their stringency, then a landfill currently subject to 40 CFR
part 60, subpart WWW would need to comply with the more stringent
requirements in the revised state plan or federal plan implementing the
revised emission guidelines (40 CFR part 60, subpart Cc) as such
sources would be existing sources with respect to the revised NSPS.\19\
States would have to update their inventory of existing landfills to
include these landfills. Note that all MSW landfills that are subject
to subpart WWW would continue to comply with the requirements found in
subpart WWW unless and until they are covered by a more stringent state
or federal plan implementing the amended emission guidelines.
---------------------------------------------------------------------------

\19\ As discussed above, the emission guidelines currently rely
on subpart WWW for their substantive requirements. As a result, any
increase in the stringency of the emission guidelines would
necessarily make them more stringent than the existing requirements
in subpart WWW.
---------------------------------------------------------------------------

III. Why is the EPA concerned about air quality effects from MSW
landfills?

The EPA is concerned about LFG emissions because of the public
health and welfare effects that result from these emissions. Landfill
gas generated from established waste (waste that has been in place for
at least a year) is typically composed of roughly 50-percent methane
and 50-percent CO2 by volume, with less than 1 percent NMOC.
In promulgating the emission guidelines in 1996, the EPA's concerns
regarding the adverse effects of emissions of LFG on human health and
welfare were focused primarily on the NMOC portion of LFG. The NMOC
portion of LFG can contain a variety of air pollutants, including VOCs
and various organic HAP, all of which have various health effects, as
discussed in section III.D of this document. In light of the Methane
Strategy, the EPA is considering changes to the emission guidelines
that are based on reducing emissions of the methane and NMOC components
of LFG. Once emitted into the atmosphere, methane contributes to
warming of the atmosphere, which over time leads to increased air and
ocean temperatures, changes in precipitation patterns, and sea level
rise, among other impacts, as discussed in section III.D of this
document.

A. Background on the MSW Landfill Sector

Section 111 of the CAA requires the EPA Administrator to list
categories of stationary sources that in the Administrator's judgment
cause or contribute significantly to air pollution that may reasonably
be anticipated to endanger public health or welfare (42 U.S.C.
7411(b)(1)(A)). On March 12, 1996 (61 FR 9905), under the authority of
CAA section 111(b)(1)(A), the EPA added the MSW landfills source
category to the priority list in 40 CFR 60.16 because, in the judgment
of the Administrator, the source category contributes significantly to
air pollution that may reasonably be anticipated to endanger public
health and welfare. In that same document, the EPA promulgated the
NSPS, which apply to new (including modified and reconstructed)
landfills under the authority of CAA section 111(b)(1)(B), and emission
guidelines, which apply to existing landfills, under the authority of
CAA section 111(d).
The EPA also defined the MSW landfills source category, identified
municipal solid waste landfill emissions (commonly referred to as LFG)
as the pollutant for which standards should be developed, and
determined the applicability thresholds and emission level of the
standards.
1. Definition
An MSW landfill is defined in the landfills regulations as: ``An
entire disposal facility in a contiguous geographical space where
household waste is placed in or on land. An MSW landfill may also
receive other types of Resource Conservation and Recovery Act (RCRA)
subtitle D wastes such as commercial solid waste, nonhazardous sludge,
conditionally exempt small quantity generator waste, and industrial
solid waste. Portions of an MSW landfill may be separated by access
roads. An MSW landfill may be publicly or privately owned. An MSW
landfill may be a new MSW landfill, an existing MSW landfill or a
lateral expansion'' (40 CFR 60.32c and 60.751).
Household waste is the primary component of MSW, accounting for 55
to 65 percent of total MSW generated, followed by the commercial and
institutional sectors.\20\ Household waste includes solid waste from
single- and multiple-family homes, hotels and motels, ranger stations,
crew quarters, campgrounds, picnic grounds and day-use recreation
areas.
---------------------------------------------------------------------------

\20\ U.S. Environmental Protection Agency. 2011. Municipal Solid
Waste Generation, Recycling, and Disposal in the United States
Tables and Figures for 2010. EPA-530-F-11-005. Washington, DC: U.S.
EPA.
---------------------------------------------------------------------------

2. Characterization of Existing Landfills
Many changes have occurred in the landfill industry since the
landfill emission guidelines were originally promulgated in 1996. Among
the changes are changes in landfill characteristics and population
(i.e., size, ownership, age); proliferation of LFG energy projects; and
the introduction of

[[Page 41778]]

new techniques for collecting, reducing, and monitoring LFG emissions.
Size, Ownership, Age. The number and size distribution of MSW
landfills in the United States has changed over the last 25 years, with
a trend toward fewer active, but larger, landfills. Since 1988, the
number of active MSW landfills in the United States has decreased by
approximately 75 percent (from approximately 7,900 in 1988 to
approximately 1,900 in 2009).^{21 22} During this time, the
overall disposal capacity has remained fairly constant, indicating a
trend towards fewer, but larger landfills.\23\
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\21\ U.S. Environmental Protection Agency. 2010. ``Municipal
Solid Waste in the United States: 2009 Facts and Figures.''
\22\ O'Brien, Jeremy K. 2006. ``Contracting out: Adapting local
integrated waste management to regional private landfill
ownership.'' Waste Management World.
\23\ Solid Waste Association of North America (SWANA). 2007.
``The Regional Privately-Owned Landfill Trend and Its Impact on
Integrated Solid Waste Management Systems.'' February 2007.
---------------------------------------------------------------------------

The data also show a trend away from public ownership. The share of
sites that are publicly owned has decreased from 83 percent in 1984 to
64 percent in 2004.^{24 25} Instead, large, private companies
have used economy of scale for cost expenditures and own multiple
sites, many of which have large capacities. To offset the cost of
constructing and maintaining landfills, facility owners construct large
facilities that attract high volumes of waste from a large geographic
area. By maintaining a high volume of incoming waste, landfill owners
have the ability to keep tipping fees relatively low, which
subsequently attracts more business.\26\
---------------------------------------------------------------------------

\24\ U.S. Environmental Protection Agency. 2010. ``Municipal
Solid Waste in the United States: 2009 Facts and Figures.''
\25\ O'Brien, Jeremy K. 2006. ``Contracting out: Adapting local
integrated waste management to regional private landfill
ownership.'' Waste Management World.
\26\ U.S. Environmental Protection Agency. 2002. Solid Waste and
Emergency Response. ``Waste Transfer Stations: A Manual for
Decision-Making.''
---------------------------------------------------------------------------

LFG Energy Projects. The number of LFG energy projects has also
increased substantially over the last two decades. In 1996, there were
approximately 160 operational LFG energy projects and approximately 700
candidate landfills according to data obtained by the EPA LMOP.
According to LMOP, as of March 2014, there are 636 operational LFG
energy projects and 450 landfills that remain candidates for energy
recovery. LMOP is a voluntary assistance program that helps to reduce
methane emissions from landfills by encouraging recovery and beneficial
use of LFG.
Availability of More Comprehensive Data. In 2010, the EPA GHGRP
began collecting information from existing MSW landfills that accepted
waste on or after January 1, 1980 and generate methane in amounts
equivalent to 25,000 metric tons of carbon dioxide equivalent
(CO2e) or more per year. According to data collected through
the GHGRP, approximately 1,200 landfills generated methane in amounts
equivalent to 25,000 metric tons of CO2e or more per year,
using a GWP of 25. (CO2e is an expression of methane in
terms of the carbon dioxide equivalents, given the methane GWP of
25.\27\) 25,000 metric tons of CO2e is equal to about 6.5
megagrams (Mg) NMOC and 1,000 Mg methane per year.\28\ (A megagram is
also known as a metric ton, which is equal to 1.1 U.S. short tons or
about 2,205 pounds.) Reporting includes data elements such as annual
modeled methane generation and methane emissions from the landfill, as
well as annual methane destruction (for landfills with GCCSs).
Beginning with reporting year 2013, the GHGRP data includes additional
data elements for which reporting was previously deferred, such as
landfill open and closure dates, waste acceptance rates, flow of LFG
for destruction, methane concentration and gas collection efficiency;
this data will be used to refine the analyses discussed in
``Methodology for Estimating Cost and Emission Impacts of MSW Landfill
Regulations. 2014'' and ``Summary of Landfill Dataset Used in the Cost
and Emission Reduction Analysis of Landfill Regulations. 2014,'' both
of which are available in the docket. The EPA plans to incorporate this
new information into the proposal for the emission guidelines review.
LMOP has collected information on landfills since the program's
inception in 1996 and maintains a database of over 2,000 existing
landfills and LFG energy projects. The database includes landfill
information provided to LMOP and from publically available sources,
including the GHGRP dataset. In addition, the EPA conducted a voluntary
landfill survey in 2010 and received information from 167 landfills.
---------------------------------------------------------------------------

\27\ IPCC Fourth Assessment Report (AR4), 2007. Climate Change
2007: The Physical Science Basis. Contribution of Working Group I to
the Fourth Assessment Report of the Intergovernmental Panel on
Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A.
(eds.)]. IPCC, Geneva, Switzerland, 104 pp.
\28\ Calculated using the AP-42 default factor of 595 ppmv and
50 percent methane. U.S. EPA, AP-42, Fifth Edition, Compilation of
Air Pollutant Emission Factors, Volume 1: Stationary Point and Area
Sources. 1995.
---------------------------------------------------------------------------

A dataset of approximately 2,400 landfills resulted from the three
sources listed above: The GHGRP, the LMOP database and voluntary survey
of landfills. Of these 2,400 landfills, approximately 1,800 have
sufficient data to use in the preliminary cost and reduction analysis
as the EPA begins its review of the emission guidelines. The creation
of the landfill dataset is detailed in the docketed memorandum,
``Summary of Landfill Dataset Used in the Cost and Emission Reduction
Analysis of Landfills Regulations 2014.'' Based on this dataset,
several observations can be made.
Location and Size. The 1,800 landfills are located in all 50 states
and two territories and range widely in size from 189 Mg to 129 million
Mg of waste-in-place as of 2014. Approximately half of the landfills
have a design capacity of at least 2.5 million Mg.
Active vs. Closed. Approximately half of the existing landfills are
still accepting waste as of 2014. Approximately 40 percent of the
landfills stopped accepting waste prior to 2005. Among landfills that
have a design capacity of at least 2.5 million Mg, only 16 percent of
the landfills stopped accepting waste prior to 2005.
Leachate Recirculation. Leachate recirculation is used at many
landfills to manage on-site leachate. Concurrently, this operational
practice accelerates waste decomposition and gas generation rates at
the landfills. Under 40 CFR part 98, subpart HH of the GHGRP, landfills
must report whether or not they employ leachate recirculation and if
so, the frequency of that recirculation. Based on GHGRP data from the
2012 reporting year, over 300 landfills accepting waste after 1987
indicated that leachate recirculation was used. Of those, over 200
landfills indicated the leachate was recirculated several times per
year over the past 10 years of operation.
Other Liquids Addition. Since 2004, 14 states have received program
approval to issue permits to MSW landfills to add liquids other than
leachate under the Research Development and Demonstration provisions of
40 CFR 258.4. This operational practice also accelerates waste
decomposition and gas generation rates at the landfills.
Other Trends. The estimated annual quantity of waste placed in MSW
landfills increased 26 percent from approximately 205 Tg in 1990 to 284
Tg in 2012.\29\ The annual amount of waste generated and subsequently
disposed in MSW landfills varies annually and depends on several
factors (e.g., the economy, consumer patterns, recycling

[[Page 41779]]

and composting programs, inclusion in a waste collection service and
the availability of other alternative options for disposal and their
price); but the total amount of MSW generated is expected to continue
to increase as the U.S. population continues to grow. The composition
of materials disposed of in MSW landfills has also changed
significantly since 1990. See section IV.C.3 of this document for
additional details on waste composition trends.
---------------------------------------------------------------------------

\29\ U.S. EPA. Inventory of U.S. Greenhouse Gas Emissions and
Sinks: 1990-2012. April 2014. See Annex 3.14, Table A-261. http://www.epa.gov/climatechange/ghgemissions/usinventoryreport.html.
---------------------------------------------------------------------------

B. What emissions are associated with existing MSW landfills?

The EPA estimates that the potential uncontrolled emissions from
the approximately 1,800 landfills in its regulatory analysis dataset
(as explained in section II.D.2 of this document) are approximately
66,400 Mg NMOC and 10 million Mg methane (258 million Mg
CO2e) in 2014.
Looking beyond the modeled dataset, the 2012 Inventory of U.S.
Greenhouse Gas Emissions and Sinks: 1990-2012 shows a growth in
uncontrolled emissions from MSW landfills, from 172.6 Tg
CO2e in 1990 to 280.0 Tg CO2e in 2012.\30\ If
controls are considered, emissions from landfills have decreased from
147.8 Tg CO2e in 1990 to 102.8 CO2e in 2012 from
both regulatory and voluntary programs.\31\
---------------------------------------------------------------------------

\30\ Ibid, Table 8-3.
\31\ Ibid, Table 8-1.
---------------------------------------------------------------------------

C. What emission reductions are currently being achieved from MSW
landfills?

1. Emission Reductions Due to Subparts Cc and WWW
To estimate the emission reductions, the EPA applied the current
design capacity and NMOC emission rate thresholds in the MSW landfills
regulations, and the time allowed for installing, expanding and
removing the GCCS to the modeled emission estimates discussed in
section IV.B of this document.
Table 2 of this document summarizes the reductions currently being
achieved at existing landfills in 2014 as a result of 40 CFR part 60,
subpart WWW and the federal and state plans implementing the emission
guidelines. This table reflects the current baseline level of control
at existing landfills: Landfills greater than or equal to 2.5 million
Mg and 2.5 million cubic meters (m\3\) must install a GCCS when NMOC
emissions reach or exceed 50 megagrams per year (Mg/yr). The table
includes emission reductions for NMOC and methane.

Table 2--Baseline Emission Reductions in 2014 at Existing Landfills
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Annual methane
Number of Number of landfills Annual NMOC Annual methane reductions
Option landfills landfills reporting but reductions (Mg/ reductions (million Mg
affected controlling not controlling yr) (million Mg/yr) CO2e/yr)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline....................................... 954 559 395 49,600 7.7 193
--------------------------------------------------------------------------------------------------------------------------------------------------------

The emission guidelines in the baseline are estimated to require
control at 559 of the 954 affected landfills in 2014 and achieve
reductions of 49,600 Mg/yr NMOC and 7.7 million Mg/yr methane (193
million Mg/yr CO2e). In the baseline we estimate that 30
percent (559/1,832) of these existing landfills will operate emission
controls in 2014 (1,832 is the number of landfills in the landfills
dataset that had sufficient data to use in the preliminary cost and
reduction analysis).
2. Other Programs Achieving Emission Reductions From Existing MSW
Landfills
Landfill owners and operators collect LFG for a variety of reasons:
To control odor, to minimize fire and explosion hazards, to recover LFG
to be used for energy recovery, to sell carbon credits, and to comply
with local, state, or federal air quality standards. This section of
this document discusses several non-EPA programs of which the EPA is
aware. These reductions complement the reductions achieved by the
current NSPS and emission guidelines framework.
i. State and Local Ordinances
The EPA is aware that some state or local ordinances require LFG
combustion for odor or safety reasons. The number of landfills
controlling under local ordinances is unknown. In addition, the state
of California recently established methane regulations \32\ to require
a GCCS to be installed at all landfills accepting waste after January
1, 1977, having at least 450,000 tons of waste-in-place, and having a
gas heat input capacity threshold of 3.0 MMBtu/hr or greater.
---------------------------------------------------------------------------

\32\ California Code of Regulations, title 17, subchapter 10,
article 4, subarticle 6, sections 95460 to 95476, Methane Emissions
from Municipal Solid Waste Landfills.
---------------------------------------------------------------------------

ii. Market-Based Mechanisms
LMOP maintains a voluntary national database of landfills and LFG
energy projects, including information on which landfills have a GCCS
in place. The EPA compared the list of landfills that are modeled to
have installed a GCCS in 2014 in the NSPS/emission guidelines dataset
to the list of landfills that are reported to have a GCCS installed in
the LMOP database. While the NSPS/emission guidelines dataset estimates
that approximately 550 landfills have installed controls to meet the
requirements of the NSPS or an approved state plan or federal plan
implementing the emission guidelines, the LMOP database shows
approximately 500 additional landfills as having installed controls,
resulting in over 1,000 landfills estimated to have a GCCS
installed.\33\ Approximately half of these 500 landfills exceed the
design capacity of 2.5 million Mg and 2.5 million m\3\, but as of 2014,
are not modeled to exceed the NMOC emission threshold that dictates
when a GCCS must be installed. Many of these systems may have been
installed to recover energy and generate revenue through the sale of
electricity or LFG. The LMOP database estimates that almost 200 of the
500 landfills with voluntary systems have an energy recovery component.
Among landfills with larger design capacities, approximately 120 of the
260 landfills with a voluntary GCCS have an energy recovery component.
Some landfills with voluntary systems may also receive revenues as a
result of the creation of carbon credits. Data from the Climate Action
Reserve indicates that more than 100 LFG capture projects in 36 states

[[Page 41780]]

have been issued credits known as Climate Reserve Tonnes (CRTs).\34\
---------------------------------------------------------------------------

\33\ See Sections II.D.2 and III.C of this document for a
detailed discussion of the modeling database and estimated
reductions under the current federal regulatory framework.
\34\ Climate Action Reserve. Issued List of CRTs as of April 17,
2014. https://thereserve2.apx.com/myModule/rpt/myrpt.asp?r=112.
---------------------------------------------------------------------------

D. What are the health and welfare effects of LFG emissions?

1. Health Impacts of VOC and Various Organic HAP
The pollutant regulated under the landfills NSPS is ``MSW landfill
emissions.'' Municipal solid waste landfill emissions, also commonly
referred to as LFG, are a collection of air pollutants, including
methane and NMOC, some of which are toxic. LFG generated from
established waste (waste that has been in place for at least a year) is
typically composed of roughly 50-percent methane and 50-percent
CO2 by volume, with less than 1 percent NMOC. The NMOC
portion of LFG can contain a variety of air pollutants, including VOC
and various organic HAP. VOC emissions are precursors to both fine
particulate matter (PM2.5) and ozone formation. Exposure to
PM2.5 and ozone is associated with significant public health
effects.^{35 36} PM2.5 is associated with health
effects including premature mortality for adults and infants,
cardiovascular morbidity such as heart attacks and respiratory
morbidity such as asthma attacks, acute and chronic bronchitis,
hospital admissions and emergency room visits, work loss days,
restricted activity days and respiratory symptoms, as well as
visibility impairment.\37\ Ozone is associated with health effects
including premature mortality, lung damage, asthma aggravation and
other respiratory symptoms, hospital and emergency department visits,
and school loss days, as well as injury to vegetation and climate
effects.\38\ Nearly 30 organic HAP have been identified in uncontrolled
LFG, including benzene, toluene, ethyl benzene and vinyl chloride.\39\
---------------------------------------------------------------------------

\35\ U.S. EPA. 2009. ``Integrated Science Assessment for
Particulate Matter (Final Report).'' EPA-600-R-08-139F. National
Center for Environmental Assessment--RTP Division. Available at
http://www.epa.gov/ncea/isa/.
\36\ U.S. EPA. 2013. ``Integrated Science Assessment for Ozone
and Related Photochemical Oxidents (Final Report).'' EPA-600-R-10-
076F. National Center for Environmental Assessment--RTP Division.
Available at http://www.epa.gov/ncea/isa/.
\37\ U.S. EPA. 2009. ``Integrated Science Assessment for
Particulate Matter (Final Report).'' EPA-600-R-08-139F. National
Center for Environmental Assessment--RTP Division. Available at
http://www.epa.gov/ncea/isa/.
\38\ U.S. EPA. 2013. ``Integrated Science Assessment for Ozone
and Related Photochemical Oxidents (Final Report).'' EPA-600-R-10-
076F. National Center for Environmental Assessment--RTP Division.
Available at http://www.epa.gov/ncea/isa/.
\39\ U.S. EPA. 1998. Office of Air and Radiation, Office of Air
Quality Planning and Standards. ``Compilation of Air Pollutant
Emission Factors, Fifth Edition, Volume I: Stationary Point and Area
Sources, Chapter 2: Solid Waste Disposal, Section 2.4: Municipal
Solid Waste Landfills''. Available at: http://www.epa.gov/ttn/chief/ap42/ch02/final/c02s04.pdf.
---------------------------------------------------------------------------

2. Climate Impacts of Methane Emissions
In addition to the improvements in air quality and resulting
benefits to human health and non-climate welfare effects discussed
above, reducing emissions from landfills is expected to result in
climate co-benefits due to reductions of the methane component of LFG.
Methane is a potent GHG with a GWP 25 times greater than
CO2, which accounts for methane's stronger absorption of
infrared radiation per ton in the atmosphere but also its shorter
lifetime (on the order of a decade compared to centuries or millennia
for carbon dioxide).\40\ According to the Intergovernmental Panel on
Climate Change (IPCC) 5th Assessment Report, methane is the second
leading long-lived climate forcer after CO2 globally.\41\
---------------------------------------------------------------------------

\40\ IPCC Fourth Assessment Report (AR4), 2007. Climate Change
2007: The Physical Science Basis. Contribution of Working Group I to
the Fourth Assessment Report of the Intergovernmental Panel on
Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A.
(eds.)]. IPCC, Geneva, Switzerland, 104 pp.
\41\ Stocker, T.F., D. Qin, G.K. Plattner, L.V. Alexander, S.K.
Allen, N.L. Bindoff, F.M. Br[eacute]on, J.A. Church, U. Cubasch, S.
Emori, P. Forster, P. Friedlingstein, N. Gillett, J.M. Gregory, D.L.
Hartmann, E. Jansen, B. Kirtman, R. Knutti, K. Krishna Kumar, P.
Lemke, J. Marotzke, V. Masson-Delmotte, G.A. Meehl, I.I. Mokhov, S.
Piao, V. Ramaswamy, D.Randall, M. Rhein, M. Rojas, C. Sabine, D.
Shindell, L.D. Talley, D.G. Vaughan and S.P. Xie. 2013: ``Technical
Summary. In: Climate Change 2013: The Physical Science Basis.
Contribution of Working Group I to the Fifth Assessment Report of
the Intergovernmental Panel on Climate Change'' [Stocker, T.F., D.
Qin, G.K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels,
Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press,
Cambridge, United Kingdom and New York, NY, USA.
---------------------------------------------------------------------------

As discussed in detail in the 2009 Endangerment Finding, climate
change caused by human emissions of GHGs threatens public health in
multiple ways. By raising average temperatures, climate change
increases the likelihood of heat waves, which are associated with
increased deaths and illnesses. While climate change also increases the
likelihood of reductions in cold-related mortality, evidence indicates
that the increases in heat mortality will be larger than the decreases
in cold mortality in the United States. Compared to a future without
climate change, climate change is expected to increase ozone pollution
over broad areas of the U.S., including in the largest metropolitan
areas with the worst ozone problems, and thereby increase the risk of
morbidity and mortality. Other public health threats also stem from
projected increases in intensity or frequency of extreme weather
associated with climate change, such as increased hurricane intensity,
increased frequency of intense storms, and heavy precipitation.
Increased coastal storms and storm surges due to rising sea levels are
expected to cause increased drownings and other health impacts.
Children, the elderly, and the poor are among the most vulnerable to
these climate-related health effects.
As documented in the 2009 Endangerment Finding, climate change
caused by human emissions of GHGs also threatens public welfare in
multiple ways. Climate changes are expected to place large areas of the
country at serious risk of reduced water supplies, increased water
pollution, and increased occurrence of extreme events such as floods
and droughts. Coastal areas are expected to face increased risks from
storm and flooding damage to property, as well as adverse impacts from
rising sea level, such as land loss due to inundation, erosion, wetland
submergence and habitat loss. Climate change is expected to result in
an increase in peak electricity demand, and extreme weather from
climate change threatens energy, transportation, and water resource
infrastructure. Climate change may exacerbate ongoing environmental
pressures in certain settlements, particularly in Alaskan indigenous
communities. Climate change also is very likely to fundamentally
rearrange U.S. ecosystems over the 21st century. Though some benefits
may balance adverse effects on agriculture and forestry in the next few
decades, the body of evidence points towards increasing risks of net
adverse impacts on U.S. food production, agriculture and forest
productivity as temperature continues to rise. These impacts are global
and may exacerbate problems outside the U.S. that raise humanitarian,
trade, and national security issues for the U.S.
Methane is also a precursor to ground-level ozone, a health-harmful
air pollutant. Additionally, ozone is a short-lived climate forcer that
contributes to global warming. In remote areas, methane is a dominant
precursor to tropospheric ozone formation.\42\ Approximately 50 percent
of the global

[[Page 41781]]

annual mean ozone increase since preindustrial times is believed to be
due to anthropogenic methane.\43\ Projections of future emissions also
indicate that methane is likely to be a key contributor to ozone
concentrations in the future.\44\ Unlike NOX and VOC, which
affect ozone concentrations regionally and at hourly time scales,
methane emissions affect ozone concentrations globally and on decadal
time scales given methane's relatively long atmospheric lifetime
compared to these other ozone precursors.\45\ Reducing methane
emissions, therefore, may contribute to efforts to reduce global
background ozone concentrations that contribute to the incidence of
ozone-related health effects.^{46 47} These benefits are global
and occur in both urban and rural areas.
---------------------------------------------------------------------------

\42\ U.S. EPA. 2013. ``Integrated Science Assessment for Ozone
and Related Photochemical Oxidents (Final Report).'' EPA-600-R-10-
076F. National Center for Environmental Assessment--RTP Division.
Available at http://www.epa.gov/ncea/isa/.
\43\ Myhre, G., D. Shindell, F.M. Br[eacute]on, W. Collins, J.
Fuglestvedt, J. Huang, D. Koch, J.F. Lamarque, D. Lee, B. Mendoza,
T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013:
Anthropogenic and Natural Radiative Forcing. In: Climate Change
2013: The Physical Science Basis. Contribution of Working Group I to
the Fifth Assessment Report of the Intergovernmental Panel on
Climate Change [Stocker, T.F., D. Qin, G.K. Plattner, M. Tignor,
S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley
(eds.)]. Cambridge University Press, Cambridge, United Kingdom and
New York, NY, USA. Pg. 680.
\44\ Ibid.
\45\ Ibid.
\46\ West, J.J., Fiore, A.M. 2005. ``Management of tropospheric
ozone by reducing methane emissions.'' Environ. Sci. Technol.
39:4685-4691.
\47\ Anenberg, S.C., et al. 2009. ``Intercontinental impacts of
ozone pollution on human mortality,'' Environ. Sci. & Technol. 43:
6482-6487.
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IV. Topics for Which the EPA Is Seeking Input

The EPA is considering several alternative approaches for achieving
additional LFG emission reductions from existing MSW landfills. The EPA
requests data and input regarding each of these approaches, or other
alternative frameworks that should be considered for existing
landfills. The EPA is specifically interested in input related to new
technologies and data on costs and emission reductions for each of
these technologies or practices. The EPA is also interested in ideas
regarding how these alternatives may be incorporated into a regulatory
framework for existing landfills. Sections IV.A through IV.F of this
document describe and request input on alternative approaches for
achieving additional LFG reductions from existing landfills.
Since the landfills regulations were implemented in 1996, the EPA
has become aware of implementation issues for which landfill owners and
operators, as well as regulators, need clarification. In this document,
the EPA is also soliciting input on the implementation issues. Section
IV.G of this document describes and requests input on these
implementation issues.

A. Taking Reductions in Methane Emissions Into Account in Reviewing the
Emission Guidelines

In light of the Methane Strategy discussed in section II of this
document, the EPA is seeking input on the extent to which methane
should be addressed under the revised emissions guidelines. The EPA is
also requesting input on potential implementation issues associated
with any adjustments that could be made to the current rule framework
or any alternative regulatory frameworks that may achieve a larger
fraction of methane emission reductions from existing landfills than
the current performance-based standard of a well-designed and well-
operated GCCS.

B. Potential Changes to Regulatory Framework for Existing Sources

The EPA is considering potential changes within the current
regulatory framework of the landfills regulations for existing sources
that would achieve further emission reductions. This section outlines
the current framework and identifies potential adjustments to that
framework. The EPA is requesting input on these potential adjustments,
the degree of emission reductions that could be achieved, corresponding
cost and implementation.
1. Current Framework
The landfills regulations in 40 CFR part 60, subparts Cc and WWW
require an MSW landfill with a design capacity of 2.5 million Mg and
2.5 million m\3\ or greater to install a GCCS once the emissions from
the landfill meet or exceed 50 Mg NMOC per year. The landfill has 30
months to install and begin operating the GCCS. This 30-month ``initial
lag time'' is the time period between when the landfill exceeds the
NMOC emission rate threshold and when controls are required to be
installed and started up. A landfill must expand the GCCS as more waste
is added to the landfill. This ``expansion lag time'' is the amount of
time allotted for the landfill to expand the GCCS into new areas of the
landfill (5 years for active areas and 2 years for areas that are
closed or at final grade). When promulgated in 1996, the best system of
emission reduction for MSW landfills was determined to be a well-
designed and well-operated landfill GCCS with a control device capable
of reducing NMOC by 98 percent by weight. Enclosed combustion devices
have the option of either reducing NMOC by 98 percent by weight or
reducing NMOC emissions to 20 parts per million, dry volume. NMOC was
established as a surrogate for LFG in the final rule.
Without any changes to the framework of the rule, over 950
landfills are affected, and 691 are required to install controls on or
before 2023. These current requirements are estimated to result in NMOC
emission reductions of 55,000 Mg/yr and methane emission reductions of
8.5 million Mg/yr (213 million Mg/yr CO2e), on average over
the next 10-year period (2014-2023). These reductions are expected to
be achieved at an average cost effectiveness of approximately $7,200
per Mg NMOC or $46 per Mg methane ($1.8 per Mg CO2e).
Additional information about these estimates can be found in the
docketed memo Preliminary Cost and Emissions Impacts Analysis for
Review of the MSW Landfills Emission Guidelines 2014.
Within the current framework of 40 CFR part 60, subparts Cc and
WWW, several parameters could be adjusted to potentially achieve
additional emission reductions. Those parameters are the design
capacity, the NMOC emissions threshold, and the timing of installing
and expanding the GCCS. The EPA conducted a preliminary analysis as
described below to estimate the emissions and cost implications of
adjusting rule parameters. Modeling options that varied these
parameters showed the following general incremental results as compared
to the current regulatory framework over the next 10-year period (2014-
2023). These preliminary cost-effectiveness values presented later in
this section IV.B include the costs to install and operate GCCS as well
as any revenue from energy recovery as discussed in further detail in
the docketed memorandum, ``Methodology for Estimating Cost and Emission
Impacts of MSW Landfills Regulations. 2014.'' Installation, operation
and maintenance of the GCCS represents over 99 percent of the annual
costs, and although the costs presented here do not include testing and
monitoring costs, those costs are expected to be nominal relative to
the control costs.
i. Reducing or Eliminating the Design Capacity Threshold
Options that decrease the design capacity threshold would make more
landfills subject to the rule. Such options also would increase the
overall reporting burden because more landfills would be required to
calculate and report their NMOC emission rates. Landfills that exceed
any lower design

[[Page 41782]]

capacity threshold and become subject to subpart XXX would be required
to obtain a Title V permit because sources subject to an NSPS must
generally obtain a Title V permit. Only a few additional landfills
would be required to install controls because landfills still must
exceed the NMOC emission rate threshold before such controls are
applied, and under the current threshold, about 72 percent of landfills
over the design capacity threshold exceed the NMOC emissions rate.
Thus, options that decrease the design capacity threshold without also
lowering the NMOC emission threshold create additional reporting and
permitting burden with minimal additional emission reductions. Modeling
showed that if the EPA decreased the design capacity threshold to 2.0
million Mg or 2.0 million m\3\, then over 90 additional landfills would
be affected by the rule and five additional landfills would require
controls, resulting in NMOC reductions of 74 Mg/yr and methane emission
reductions of 11,500 Mg/yr (287,000 Mg/yr CO2e). These
reductions could be achieved at a cost effectiveness of approximately
$9,900 per Mg NMOC or $64 per Mg methane ($2.6 per Mg CO2e).
The EPA also explored decreasing the NMOC emission threshold in
conjunction with decreasing the design capacity. Modeling showed that
if the EPA decreased the design capacity threshold to 2.0 million Mg or
2.0 million m\3\ and reduced the NMOC emission threshold to between 34
and 40 Mg/yr, then approximately 90 additional landfills would be
affected by the rule and 80 to 160 additional landfills would require
controls, resulting in additional NMOC reductions of 2,100 to 3,200 Mg/
yr and methane reductions of 328,000 to 494,000 Mg/yr (8.2 to 12.3
million Mg/yr CO2e). These additional reductions could be
achieved at an incremental cost effectiveness of between $16,000 and
$18,000 per Mg NMOC or $100 to $115 per Mg methane ($4 to $5 per Mg
CO2e).
In addition, if the EPA were to remove the design capacity
threshold, then a significant number of additional landfills would be
subject to the rule. Out of the approximately 1,800 existing landfills
with sufficient data to include in the preliminary analysis for the
review of the emission guidelines, over 850 have a design capacity of
less than 2.5 million Mg or 2.5 million m\3\. Without a design capacity
threshold, the NMOC emission rate would be the only criterion for
installing controls. Thus, these landfills would be required to begin
calculating and reporting their NMOC emission rate. They would also be
required to obtain a Title V permit. A smaller number of additional
landfills would be required to install controls, because currently only
those landfills below the design capacity threshold that exceed the
NMOC emission rate require controls. Note that as landfills continue to
add waste and continue to calculate and report the annual NMOC emission
rate, over time, more landfills would be required to install controls,
which would thus achieve additional emission reductions. The EPA
requests input on whether or not adjustments to the design capacity
threshold should be considered.
ii. Reducing NMOC Emission Threshold
Decreasing the NMOC emissions threshold would not change the number
of landfills subject to the rule or affect the overall reporting
burden. However, a lower NMOC emissions threshold would require more
landfills to install controls. Although an NMOC emission threshold
would continue to use NMOC as a surrogate for LFG, additional methane
reductions could be achieved as a result of lowering the NMOC
threshold, which is consistent with the President's Methane Strategy as
described in section II of this document.
Modeling showed that if the EPA decreased the NMOC threshold to 40
Mg/yr NMOC, then approximately 80 additional landfills would require
controls, resulting in additional NMOC reductions of 1,900 Mg/yr and
methane reductions of 303,000 Mg/yr (7.6 million Mg/yr CO2e)
as compared to the current rule requirements. These additional
reductions could be achieved at an incremental cost effectiveness of
approximately $16,000 per Mg NMOC or $100 per Mg methane ($4 per Mg
CO2e). The EPA's preliminary analysis did not include a
reduction of NMOC threshold below 40 Mg/yr without also reducing the
design capacity threshold. The preliminary emission reduction impacts
of reducing both of these parameters are presented in section IV.B.1 of
this document. The EPA requests input on whether or not adjustments to
the NMOC emission threshold should be considered.
iii. Adjustments to Initial or Expansion Lag Times
As mentioned above, ``lag time'' is the period between when the
landfill exceeds the NMOC emission rate threshold and when controls are
required to be initially installed (or expanded) and started up. The
emission reductions achieved by reducing the initial or expansion lag
time are affected by the size of the landfill, waste placement patterns
and annual acceptance rates. For example, the size of the landfill and
the filling cycle affect how much and when emission reductions would be
achieved. Based on input received from commenters,\48\ large filling
areas at modern landfill designs typically do not close before 7 years.
Because the landfills regulations allow two options for expanding the
GCCS (2 years after initial waste placement in closed areas and 5 years
after initial waste placement in active areas), any reduction to the 2-
year lag time for closed areas would not likely achieve any actual
additional reductions from larger existing landfills because the
majority of landfills are complying with the 5-year deadline instead of
the 2-year deadline. Some of the smaller landfills may achieve final
grade in a shorter time period. Modeling showed that if the EPA
decreased the initial lag time to 2 years, then an additional NMOC
reduction of approximately 600 Mg/yr and methane reductions of 88,000
Mg/yr (2.2 million Mg CO2e/yr) would be achieved as compared
to the current rule framework. These additional reductions could be
achieved at an incremental cost effectiveness of approximately $4,700
per Mg NMOC or $30 per Mg methane ($1.2 per Mg CO2e).
---------------------------------------------------------------------------

\48\ The EPA conducted outreach with small entities, state and
local officials, and representative organizations, hereinafter
referred to as commenters.
---------------------------------------------------------------------------

Modifying the 5-year provision may also have a limited effect on
emission reductions. Many landfills in wet climates are already
installing wells ahead of the 5-year schedule for odor or energy
recovery purposes. Modeling showed that if the EPA decreased the
expansion lag time to 2 years, then an additional NMOC reduction of
nearly 1,000 Mg/yr and methane reductions of 152,000 Mg/yr (3.8 million
Mg/yr CO2e) could be achieved as compared to the current
rule framework. These additional reductions could be achieved at an
incremental cost effectiveness of approximately $17,000 per Mg NMOC or
$106 per Mg methane ($4.3 per Mg CO2e).
The EPA received input from commenters expressing concern about the
potential shortening of lag times. The comments indicated that wells
located in these areas are more frequently damaged as a result of daily
filling operations and the movement of equipment. Damaged wells must be
repaired with well extensions and/or re-drilling of wells. In addition,
waste in active fill areas undergoes significant settlement. This
settlement affects the alignment of gas header equipment,

[[Page 41783]]

requiring more frequent repairs, troubleshooting and replacement of
equipment. These repairs can add a significant cost to the construction
and operation of a GCCS that are not currently accounted for in the
LFGcost model estimates and also increase the amount of system down
time.
In addition to the implementation concerns, reducing the lag times
would require more frequent mobilization of drill rig equipment and
purchase of GCCS infrastructure and system repairs, which could lead to
higher costs. Note the preliminary cost effectiveness estimates shown
above do not include any cost adjustments to repair wells damaged in
active areas. We seek input on how to account for these costs.
Commenters also raised several practical concerns with reducing the
expansion lag time. Reducing the expansion lag time would result in
more wells located in active fill areas because more of the face of the
landfill is active after only 2 years of waste acceptance and the
landfill owner or operator must add wells into these active areas
sooner. In addition, active fill areas are still in the aerobic phase
of waste decomposition. Installing wells in areas with high oxygen
levels increases the chance of subsurface fires. It also leads to more
frequent exceedances of the current wellhead monitoring standards for
oxygen. The EPA requests input on the assumptions outlined above and
whether or not adjustments to lag times should nonetheless be
considered.
Horizontal Collectors. Horizontal LFG collection wells may provide
some relief to the implementation concerns that have been raised, while
also allowing for the wells to be installed more quickly after the
waste is placed in the landfill. These types of wells are used in
active fill areas and consist of perforated pipe in gravel-filled
trenches constructed within the waste mass as an active area is filled.
The wellheads are installed remotely outside of the active fill area to
allow landfill owners/operators to monitor the wells. Although the
horizontal collection infrastructure is installed as the waste is
placed in the fill area, the collectors are not brought online under an
active vacuum until a sufficient refuse layer has been placed on top of
the collectors. Sufficient refuse is necessary in order to prevent air
infiltration in the landfill. The time to accumulate sufficient waste
is, however, often shorter than the time needed to install vertical
wells, and can be as short as a few months after refuse is buried.\49\
As a result, the installation of horizontal collectors could result in
LFG being collected sooner.
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\49\ Barlaz et al., Controls on Landfill Gas Collection
Efficiency: Instantaneous and Lifetime Performance. 59 J. Air &
Waste Mgmt. Ass'n 1399, 1402-03 (Dec. 2009).
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The EPA is aware of several horizontal collector installations,
including several landfills in California \50\ and 18 different
landfills in the voluntary data collection effort for this rulemaking;
see ``Summary of Landfill Dataset Used in the Cost and Emission
Reduction Analysis of Landfills Regulations. 2014.''
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\50\ SCS Engineers, Technology and Management Options for
Reducing Greenhouse Gas Emissions. Prepared for California
Integrated Waste Management Board.
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The shorter length of time associated with bringing horizontal
collectors online can be especially important at landfills employing
liquids recirculation techniques or located in wetter climates, given
the higher LFG generation rates at those sites (as discussed earlier in
this section IV.B.1). Quickly bringing these collectors online has
added the benefit of proactively addressing odor concerns at landfills.
These systems are also useful in landfills that practice ``over-
filling,'' where new waste is placed on top of a section of the
landfill that was capped temporarily. Some implementation concerns with
horizontal collectors have been expressed, particularly regarding their
shorter lifetime than vertical wells and the need for more frequent
replacement.
The EPA requests input on the assumptions outlined above and
whether adjustments to lag times should be considered.
iv. Adjustments to the Length of Time That Control Equipment Must
Remain Operational
The EPA is requesting input on the criteria and timing for capping
or removing the GCCS. Under 40 CFR part 60, subpart WWW, a landfill may
cap or remove the GCCS if the following three criteria are met: (1) The
landfill is closed; (2) the GCCS has been in operation for 15 years;
and (3) three successive tests for NMOC emissions are below the NMOC
emission threshold of 50 Mg/yr. Depending on the waste-in-place of the
landfill at closure and other site-specific factors (e.g., waste
composition, climate), it may take greater than 30 years after closure
for a large modern landfill to emit less than the 50 Mg per year NMOC
emission threshold, and in turn qualify for capping or removing the
GCCS.
Although some commenters expressed concerns about the quantity of
emissions after landfills have closed and the GCCS has ceased to
operate, the preliminary analysis the EPA conducted demonstrated that
approximately 130 landfills that have closed or will close by 2023 will
require a GCCS to be operated for between 15 and nearly 70 years after
the landfill has stopped accepting waste. The exact length of the
period after landfill closure is commensurate with the size and
corresponding emissions profile of each affected landfill. Nonetheless,
the EPA is requesting input on whether there are other ways to ensure
emissions are minimized in the later stages of a landfill's lifecycle.
Specifically, the EPA is seeking input on whether the three criteria
listed above are appropriate. We also seek input on alternative
approaches, such as consecutive quarterly measurements below a surface
emission threshold. Note that RCRA, specifically subpart F of part 258,
also requires supplemental basic post-closure care to maintain cover
integrity, which includes cover material requirements, design criteria
for final cover systems, and post-closure care such as maintaining the
integrity of the final cover and maintaining and operating a gas
monitoring system. The California landfill methane regulation \51\
requires that systems stay in place until the landfill has operated the
equipment for at least 15 years and the surface methane concentration
measurement (instead of the measured NMOC emission cutoff rate) does
not exceed a 500 parts per million (ppm) instantaneous reading or a 25
ppm integrated reading.
---------------------------------------------------------------------------

\51\ California Code of Regulations, title 17, subchapter 10,
article 4, subarticle 6, section 95467, Methane Emissions from
Municipal Solid Waste Landfills.
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v. Other Potential Adjustments
The California landfill methane regulation \52\ uses a combination
of waste-in-place and gas heat input capacity in lieu of design
capacity and NMOC thresholds to determine which landfills are subject
to GCCS requirements. Under the California regulation, a GCCS must be
installed at all landfills accepting waste after January 1, 1977,
having at least 450,000 tons of waste-in-place, and having a gas heat
input capacity threshold of 3.0 MMBtu/hr or greater.
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\52\ California Code of Regulations, title 17, subchapter 10,
article 4, subarticle 6, sections 95460 to 95476, Methane Emissions
from Municipal Solid Waste Landfills.
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The Climate Action Reserve also incorporated waste-in-place
criteria in

[[Page 41784]]

version 4.0 of its Landfill Protocol.\53\ This protocol includes waste-
in-place thresholds for landfills that recover energy and those
thresholds vary from 0.72 million Mg for landfills located in a non-
arid area (receiving 25 inches or greater precipitation per year) to
2.17 million Mg for landfills located in an arid area (receiving less
than 25 inches of precipitation per year) to determine what offset
projects are eligible. Coupling a precipitation indicator with a waste-
in-place threshold recognizes that LFG emission generation rates are
affected by the quantity of waste disposed as well as the moisture
present in the landfill, either due to the local climate, or other
liquids added to a landfill, as discussed earlier in this section
IV.B.1.
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\53\ Climate Action Reserve. Landfill Project Protocol. Version
4.0. June 29, 2011.
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The EPA requests input on whether it should pursue an alternative
set of thresholds to determine which landfills are subject to the
revised emission guidelines and what criteria trigger the installation
of a GCCS.
vi. Potential Unique Treatment of Landfills Located in Wet Climates or
Those Employing Leachate Recirculation or Other Liquids Addition
The EPA also seeks input on whether it should consider reducing the
design capacity thresholds or initial and expansion lag times for
landfills that are located in a wet climate or that recirculate
leachate or add other liquids to the landfills to accelerate
decomposition of the waste. Wetter wastes decompose more quickly than
drier wastes and as a result generate more LFG in the short term.
Therefore, it may be appropriate to require these landfills to install
and expand the gas collection system sooner. Similarly, smaller
landfills in wetter climates, or those employing leachate recirculation
(or other liquids addition), may also generate earlier spikes in LFG
emissions that could exceed the NMOC threshold. Although these
landfills are not affected by the current design capacity threshold of
2.5 million Mg and 2.5 million m\3\, if a smaller design capacity
threshold or an alternative waste-in-place based threshold were adopted
for these wet landfills, more emission reductions may be achieved.
If a separate set of thresholds and/or lag times were to apply to
these wet landfills, or if an adjusted modeling provision were adopted
(see section IV.E.1 of this document), the EPA requests input on how a
wet landfill might be defined. For example, a wet landfill could be
defined as a landfill that has precipitation of greater than 25 inches
per year and/or recirculates leachate or adds other liquids to the
landfill.
vii. Definition of Modification
The EPA in this ANPRM is seeking input on options to achieve
additional emissions reductions from existing landfills under CAA
section 111(d). In light of our interest in reducing the methane and
NMOC components of LFG, the EPA is also seeking input on whether it is
reasonable to review the definition of modification for landfills. The
EPA solicits input on changes that may be appropriate and whether these
changes should be enacted to achieve additional emission reductions.

C. Emission Reduction Techniques and GCCS Best Management Practices

As mentioned previously, the EPA is considering potential changes
within the current regulatory framework of the landfills regulations
for existing sources that would achieve further emission reductions.
This section discusses specific LFG control technologies and BMPs for
GCCS and landfill operations to improve gas collection efficiencies.
The EPA is soliciting input to evaluate the emission reductions
achieved by the specific technologies and BMPs discussed later in this
section to assess whether any technologies and practices could be
applied to the landfills regulations for existing sources to achieve
further reductions of LFG.
The EPA will review the performance data, practical application,
and cost of these BMPs or technologies to determine if and how they
could be incorporated in conjunction with the current performance-based
standard. Promotion of technologies and practices to achieve reductions
of GHG from landfills complements the recently issued Methane Action
Plan discussed in section II of this document.
The EPA is also requesting input on other technologies or BMPs that
might be appropriate to encourage under the emission guidelines, the
cost and emission reduction potential of each of these alternatives,
and how each of these other approaches might be incorporated into the
current rule framework or a new alternative rule framework.
1. Oxidation Technologies
The EPA is considering whether any emerging technologies may
achieve additional emission reductions for existing landfills. As part
of its consideration, the EPA will evaluate the extent to which the
technology is adequately demonstrated for existing landfills.
The EPA is aware of several technologies that increase the methane
oxidation rate, thereby reducing the amount of methane that could
escape through the surface of the landfill. The principle of these
technologies is the use of methanotrophic bacteria, commonly found in
most soils and compost, to oxidize methane into water, carbon dioxide,
and biomass.
A biocover is a cover material designed to enhance methane
oxidation and is typically made of two layers--a permeable layer that
consists of gravel, broken glass, sand or other media to evenly
distribute the LFG to the oxidation media and an oxidation layer that
typically consists of soil, compost, mulch or other organic media. The
oxidation media contains methanotrophic bacteria from the waste
decomposition process. One disadvantage of alternative cover
technologies is their sensitivity to environmental conditions because
the productivity of methanotrophic bacteria is highly dependent on the
bacteria's surroundings. Certain conditions, including temperature,
moisture and pH, must be maintained to optimize methane oxidation
rates.\54\
---------------------------------------------------------------------------

\54\ BAAQMD. Greenhouse Gas Mitigation: Landfill Gas and
Industrial, Institutional and Commercial Boilers, Steam Generators
and Process Heaters. Bay Area Air Quality Management District,
prepared by URS Corporation. April 2008.
---------------------------------------------------------------------------

Methane oxidation occurs to some degree in various types of
traditional landfill covers, including simple soil covers. Some
landfills use compost, yard waste and other organic wastes and
materials as a type of naturally occurring biocover. Chipped rubber
tires, Styrofoam and yard waste are other common types of waste that
could serve as good methanotrophic media when mixed with soil or
compost.\55\
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\55\ BAAQMD. Greenhouse Gas Mitigation: Landfill Gas and
Industrial, Institutional and Commercial Boilers, Steam Generators
and Process Heaters. Bay Area Air Quality Management District,
prepared by URS Corporation. April 2008.
---------------------------------------------------------------------------

The most common biocover in use at landfills is shredded yard waste
used as alternative daily cover.\56\ Biocovers consisting of naturally
occurring and often readily available materials may provide a cost
effective method to increase methane oxidation, thus decreasing methane
emissions, at the surface of existing landfills. The EPA is requesting
information to characterize the prevalence of the practice of using
these types of naturally occurring biocovers at existing U.S. landfills
and

[[Page 41785]]

the costs to manage and apply these materials.
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\56\ Sullivan, P. The Importance of Landfill Gas Capture and
Utilization in the U.S. April 6, 2010.
---------------------------------------------------------------------------

The MSW landfills subpart of the GHGRP (40 CFR part 98, subpart HH)
had used a default value of 10 percent for the amount of methane
oxidized when calculating methane emissions from MSW landfills.
However, recent research studies indicate that a default value of 10
percent may be underestimating the level of oxidation occurring at
existing landfills and the amount of methane oxidized may be
considerably higher, depending on cover type and other site-specific
conditions.\57\ A 2009 literature review found an average value of 35
percent for traditional landfill cover methane oxidation rates.\58\ A
2011 article documents a 4-year research study of over 37 seasonal
sampling events at 20 landfills across the United States with
intermediate covers reported up to 37 percent average oxidation for
soil covers.\59\ In addition, recent research demonstrates that daily
soil covers oxidize methane to a greater degree than many low
permeability final soil covers, suggesting oxidation rates of 20 to 55
percent.\60\ As a result, recent final revisions to the GHGRP published
in the Federal Register on November 29, 2013 (78 FR 71904), now allow
for the use of higher oxidation values (25 percent and 35 percent), in
addition to the 10 percent value, if methane flux through the soil
cover is of a certain amount and there is 24 inches or more of soil
cover.\61\ Co-oxidation of NMOC has been observed during use of these
alternative landfill cover materials, which has the potential to reduce
odors and toxic air pollutants.\62\
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\57\ Sullivan, P. The Importance of Landfill Gas Capture and
Utilization in the U.S. April 6, 2010.
\58\ Chanton, J.; Powelson, D.; Green, R. Methane oxidation in
landfill cover soils, is a 10% default value reasonable? Journal of
Environmental Quality. 38, 654-663 (2009).
\59\ Chanton, J.; Abichou, T.; Langford, C.; Hater, G.; Green,
R.; Goldsmith, D.; Swan, N. Landfill Methane Oxidation Across
Climate Types in the U.S. Environmental Science And Technology. 45,
313-319 (2011).
\60\ Sullivan, P. The Importance of Landfill Gas Capture and
Utilization in the U.S. April 6, 2010.
\61\ If methane flux is less than 10 grams per square meter per
day, then a 35 percent oxidation fraction can be used. If methane
flux is between 10 to 70 grams per square meter per day, then a 25
percent oxidation fraction can be used. If methane flux is greater
than 70 grams per square meter per day, then a 25 percent oxidation
fraction can be used.
\62\ U.S. EPA. Available and Emerging Technologies for Reducing
Greenhouse Gas Emissions from Municipal Solid Waste Landfills. June
2011.
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Biocover application costs may vary widely depending upon
availability of material and the level of monitoring, and many
materials would most likely be on site or easily obtained for free or
for a nominal cost associated with transporting the materials from a
nearby or co-located yard waste or compost facility.\63\
---------------------------------------------------------------------------

\63\ BAAQMD. Greenhouse Gas Mitigation: Landfill Gas and
Industrial, Institutional and Commercial Boilers, Steam Generators
and Process Heaters. Bay Area Air Quality Management District,
prepared by URS Corporation. April 2008.
---------------------------------------------------------------------------

RCRA Subtitle D addresses cover and capping requirements for MSW
landfills. Specific requirements address the frequency and type of
covers allowed, including provisions for requesting the use of
alternative materials (40 part 258, subpart C). These operating
parameters are in place to control disease vectors, fires, odors,
blowing litter and scavenging at the landfill, but are not covers that
specifically promote oxidation of LFG. Design criteria for final cover
systems (40 part 258, subpart F) were also established to minimize
water infiltration and erosion of the landfill, rather than release of
LFG or its constituents. Rules regarding the use of daily, intermediate
and final cover are governed by RCRA Subtitle D; however, research
indicates that biocovers may help to reduce emissions of methane, a
primary constituent of LFG.
Another method for increasing the oxidation rate is to route
passively vented LFG through a vessel containing methane-oxidizing
media, commonly referred to as a biofiltration beds or biofilters.
Biofilter media have included compost or chipped yard waste mixed with
recycled shredded tires or Styrofoam peanuts as well as sand and soil
mixtures. Choosing the proper media with sufficient gas conductivity is
important to reduce the possibility of back pressure in the
landfill.\64\ Biofilters have been tested for use at landfills over
only the past 10 to 15 years. Studies of passively-aerated methane
biofilters have shown methane oxidation rates vary widely by type of
biofilter media but could reach values between 19 and 98
percent.^{65 66}
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\64\ BAAQMD. Greenhouse Gas Mitigation: Landfill Gas and
Industrial, Institutional and Commercial Boilers, Steam Generators
and Process Heaters. Bay Area Air Quality Management District,
prepared by URS Corporation. April 2008.
\65\ Abichou, T.; Chanton, J.; Powelson, D. Field Performance of
Biocells, Biocovers, and Biofilters to Mitigate Greenhouse Gas
Emissions from Landfills. Florida Center for Solid and Hazardous
Waste Management, University of Florida. March 2006.
\66\ Morales, J.J. Mitigation of Landfill Methane Emissions from
Passive Vents by Use of Oxidizing Biofilters. Fall 2006.
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Biofilters are likely feasible for use at small existing landfills
or existing landfills with passive gas collection systems due to the
size of the biofiltration bed required to treat the mixture of air and
LFG. Due to the nature of passive gas collection systems, this
technology lacks the ability to control and monitor the oxidation of
methane in the LFG.\67\ In general, biofilter costs are expected to be
lower than biocover costs due to their smaller scale and utilization of
existing passive vents.
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\67\ U.S. EPA. Available and Emerging Technologies for Reducing
Greenhouse Gas Emissions from Municipal Solid Waste Landfills. June
2011.
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No data exist on the long-term performance, effectiveness, or
maintenance requirements of biocovers or biofilters.^{68 69 70}
Therefore, the EPA is requesting information about application of these
technologies to better understand these characteristics for full-scale
use of biocovers and biofilters. The EPA is also seeking input on
biocover parameters and their effect on oxidation. Such parameters may
include depth, soil characteristics, measurement and their affect on
percent oxidation. The EPA is also seeking input on appropriate
mechanisms to monitor the performance of these alternatives.
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\68\ U.S. EPA. Available and Emerging Technologies for Reducing
Greenhouse Gas Emissions from Municipal Solid Waste Landfills. June
2011.
\69\ Abichou, T.; Chanton, J.; Powelson, D. Field Performance of
Biocells, Biocovers, and Biofilters to Mitigate Greenhouse Gas
Emissions from Landfills. Florida Center for Solid and Hazardous
Waste Management, University of Florida. March 2006.
\70\ Yazdani, R, and Imhoff, P. Contractor's report to
CalRecycle: Biocovers at Landfills for Methane Emissions Reduction
Demonstration. October 2010.
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2. Best Management Practices
The EPA is considering how certain BMPs that achieve additional
emission reductions for existing landfills may be encouraged under a
revised regulatory framework. The EPA seeks input on how to demonstrate
that the BMPs are properly implemented and what additional maintenance
records or other requirements might demonstrate that the BMPs can
ensure the same level of environmental protection as the current
framework. The EPA also invites input on other requirements that could
be adjusted to encourage BMPs.
i. LFG Collection From Leachate Removal Systems
The EPA is aware of landfills that have connected the LFG
collection system and leachate collection system; however, references
suggest that connection of these systems is not common at landfills
that do not employ leachate recirculation.\71\ The efficiency

[[Page 41786]]

of capturing LFG emissions through this BMP depends on the efficiency
of both the LFG collection system and the leachate recirculation
system. Section 60.752(b)(2)(i)(D) of subpart WWW recognizes that
leachate collection components may be part of a site-specific
collection and control system design plan. Because the design plan is
not prescriptive and instead contains design and operational standards
that are site-specific, the design plan has the flexibility to include
collection of LFG from leachate collection systems.
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\71\ SCS Engineers, Technology and Management Options for
Reducing Greenhouse Gas Emissions. Prepared for California
Integrated Waste Management Board. Prepared by SCS Engineers. April
2008.
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The cost of each connection of GCCS to a leachate removal system
would include $400 to $650 for a LFG wellhead and $10 to $15 per foot
for a 3- or 4-inch HDPE pipe (2008 cost estimates).\72\ However, there
are currently no broad mandates for requiring gas collection from
leachate removal systems. The EPA requests input on the efficacy and
costs of enhancing gas collection systems to collect LFG from leachate
removal or storage systems. The EPA also requests information on the
types of landfills currently collecting gas from leachate removal
systems and the specifics of the gas collection systems used in
practice. The EPA will use this information to evaluate if and when the
use of an enhanced gas collection system that collects LFG from the
leachate removal system may be appropriate.
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\72\ California Integrated Waste Management Board, Technologies
and Management Options for Reducing Greenhouse Gas Emissions From
Landfills, April 2008.
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ii. Preventing Waterlogged Wells
The EPA also seeks input on requiring a gas collection system to
more proactively prevent waterlogged wells, perhaps through the use of
leachate removal pumps or alternative GCCS infrastructure. Leachate and
condensate can accumulate in collection wells, blocking LFG capture.
Because a flooded well cannot collect gas, fixing a flooded well would
have a high emission reduction potential.
The most practical and cost effective method for keeping liquid out
of gas extraction wells is to prevent its entry in the first place by
ensuring proper sealing and grading at the surface. Infiltration of
leachate from within the waste mass is more difficult to control. Once
liquid is inside the well, it often must be removed via pumping to
restore the gas collection capability of the well. When performed in
conjunction with effective leachate removal, it may be possible to
dewater wells with a portable pump and a mobile storage tank that can
be used to transport liquid removed from the well to a suitable
leachate disposal point. Multiple iterations of dewatering could be
required at each well because liquid often seeps back into the well
after pumping. While labor intensive, this approach alleviates the need
for a dedicated pump and piping at multiple wells. If liquid
accumulation in wells is an ongoing issue, then a dedicated pumping
system may be suitable. Long term costs for a dedicated pumping system
are still high, including the initial cost of pumps and piping, as well
as ongoing operation and maintenance costs and disposal of the
leachate. A single well dewatering pump system could cost over
$3,000,\73\ but could also improve LFG collection and GHG emission
reduction.
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\73\ Kaminski, D. and M. Varljen. Increasing LFG Collection
Rates Using Gas Well Dewatering Systems: Lessons Learned. 15th
Annual LMOP Conference. January 2012.
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Another method for reducing GHG emissions at landfills with
waterlogged wells is to install a surface collector. A surface
collector usually consists of perforated pipes laid across the top of
the waste mass and covered by an impermeable geomembrane or by final
cover. Surface collectors can be used to collect gas from a wet
landfill where traditional horizontal and vertical wells fail due to
water infiltration. Surface collectors can be used with or instead of
horizontal collector systems.\74\ Because surface collectors are
installed after final waste acceptance, they are not effective in
controlling LFG emissions while the landfill is open and accepting
waste. Surface collectors also do not apply a vacuum into the waste so
they are only effective at controlling gas that has escaped other
collection systems. Their impact on emissions is therefore expected to
be low in cases where a well-designed and well-operated LFG collection
system already exists. The overall cost of surface collectors is
comparatively high due to additional geomembrane material costs, if
they are not already required by regulations. One 2008 study estimates
the cost of installing a geomembrane to be $40,000 to $50,000 per acre
of landfill surface. If a landfill already has a geomembrane, the added
cost would be $25 to $35 per linear foot for a 6-foot deep trench and
gravel backfill.\75\
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\74\ California Integrated Waste Management Board, Technologies
and Management Options for Reducing Greenhouse Gas Emissions From
Landfills, April 2008.
\75\ California Integrated Waste Management Board, Technologies
and Management Options for Reducing Greenhouse Gas Emissions From
Landfills, April 2008.
---------------------------------------------------------------------------

Wellhead operating parameters in 40 CFR part 60, subpart WWW
require that each owner or operator of an MSW landfill either operate
the collection system with a negative pressure at each wellhead or, in
areas with a geomembrane or synthetic cover, establish acceptable
pressure limits in the design plan. These performance standards help
identify any inoperable wells resulting from flooding. Surface
emissions monitoring would also help identify any elevated methane
levels resulting from an inoperable well. Because some of the wells at
existing landfills may have been installed for 15 years or more, the
EPA requests input on whether the current combination of wellhead
monitoring and surface emission monitoring is sufficient for
identifying inoperable wells, especially in cases where wells have been
installed for a significant amount of time. If the monitoring systems
in 40 CFR part 60, subpart WWW are deficient for identifying flooded
wells, the EPA also asks for input on whether any additional
recordkeeping, such as periodic measurement of liquid levels in gas
wells, might be useful to identify flooded wells that are not
collecting gas. The EPA requests input on whether any more specific
corrective action guidance should be developed, such as the need to
dewater the well or employ alternative GCCS technologies such as
surface collectors if a flooded well is identified.
iii. Redundant Seals
The EPA is also considering a BMP of requiring redundant seals and
the use of enhanced sealing materials on wellheads. One study includes
a survey using a forward-looking infrared camera suggesting that LFG
wellheads and other surface penetrations present high potential for
concentrated leaks of organic compounds.\76\ The use of advanced seals
at wellheads may help to ensure that the well can apply sufficient
vacuum to the landfill to facilitate gas extraction while preventing
leaks of LFG to the atmosphere. The design for vertical wells typically
includes the use of bentonite or bentonite soil mixtures near the
surface as part of the well boring backfill to reduce the potential for
air to be pulled into the well.\77\ Compacted backfill soil can also be
considered, but may not be practicable and adds risk of damaging the
well casing pipe. A well's connecting pipes

[[Page 41787]]

are typically sealed using three different techniques: (1) Bentonite
clay seal, (2) compacted clay seal or (3) plastic well bore seal.
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\76\ ARCADIS. Quantifying Methane Abatement Efficiency at Three
Municipal Solid Waste Landfills. Prepared for U.S. EPA/ORD. January
2012.
\77\ California Integrated Waste Management Board, Technologies
and Management Options for Reducing Greenhouse Gas Emissions From
Landfills, April 2008.
---------------------------------------------------------------------------

Because a good seal is critical for proper well performance,
multiple seals are often used. Many engineers already require two and
sometimes three seals in a well when preparing design plans for
GCCS.\78\ However, for wells that are not properly sealed, their zone
of influence is likely reduced, resulting in LFG between wells not
being collected. Costs can range from $500 to $2500 per well based on
2008 estimates depending on the type of seal used.\79\
---------------------------------------------------------------------------

\78\ Ibid.
\79\ Ibid.
---------------------------------------------------------------------------

Because the design plan is not prescriptive and instead contains
design and operational standards that are site-specific, the design
plan has the flexibility to determine the number or type of seals in
order to accommodate the conditions and climates at different
landfills. This site-specific approach also provides for continued
flexibility for future design plans to incorporate new sealing
materials that may be more efficient than those currently available.
The design plan, coupled with wellhead and surface monitoring
requirements, ensures that leaks from wells are minimized. The EPA is
soliciting input on what mechanisms, if any, might be appropriate to
further promote or mandate enhanced seals in this emission guidelines
review.
iv. Early Installation of Final Cover
Early installation of final cover systems can also reduce methane
emissions. Current rules for landfills under RCRA Subtitle D require
intermediate cover (typically at least 12 inches of native soil) to be
installed in areas of the landfill that are no longer receiving waste
or will not be used for over 12 months within 180 days of final waste
placement (40 CFR part 258, subpart C). The final cover system must
consist of an infiltration layer of at least 18 inches of earthen
material covered by an erosion layer of at least 6 inches of earthen
material that is capable of sustaining native plant growth. An
alternative cover design may be used as long as it provides equivalent
protection against infiltration and erosion (40 CFR part 258, subpart
F). Once a landfill has received its final shipment of waste, it must
begin closure operations within 30 days. A landfill, however, may delay
closure for up to 1 year if additional capacity remains. Any further
delays after 1 year require approval from the appropriate state agency.
After beginning, all closure activities must be completed within 180
days.
Despite these rules, landfill operators often leave intermediate
cover in place for years or even decades and intermediate cover
frequently is the only cover on the majority of the landfill surface.
Recent studies indicate that installation of intermediate and final
cover has a direct and significant effect on LFG emissions.\80\
Intermediate cover significantly reduces emissions compared to daily
cover on working faces. Final cover has the ability to reduce emissions
even further compared to intermediate cover. By installing these more
rigorous cover systems sooner, significant emissions may be prevented
from being released. Furthermore, final cover has been shown to
increase LFG collection efficiency at landfills with a gas collection
system.\81\ Early installation of cover should not incur any additional
cost to the landfill as long as waste acceptance or placement plans do
not change after the cover (particularly final cover) is installed.
Early installation of cover could result in a cost savings due to the
general increase in the cost of materials over time and the added gas
collection realized when more rigorous cover systems are installed--
especially if the gas is collected for beneficial use.
---------------------------------------------------------------------------

\80\ Goldsmith et al., Methane Emissions from 20 Landfills
Across the United States Using Vertical Radial Plume Mapping,
Journal of the Air & Waste Mgmt. Association, 62:2, 183-197 (2012).
\81\ Barlaz et al., Controls on Landfill Gas Collection
Efficiency: Instantaneous and Lifetime Performance, Journal of the
Air & Waste Mgmt. Association, 59, 1399-1404 (2009).
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3. Organics Diversion and Source Separation
LFG is a by-product of the decomposition of organic material in MSW
under anaerobic conditions in landfills. The amount of LFG created
primarily depends on the quantity of waste and its composition and
moisture content, as well as the design and management practices at the
site. Decreasing the amount of organics disposed in landfills would
decrease the generation of LFG.
Organic materials are historically the largest component of
materials discarded in the MSW stream, constituting nearly 49 percent
of discarded material in 2012. Food waste is the largest portion of the
organic materials, followed by paper and paperboard, yard trimmings and
wood wastes.\82\ Material recovery, including composting and recycling,
has been increasing over time for all materials, except rubber and
leather. For example, the percent of paper and paperboard that is
recovered has increased from 16.9 percent in 1960 to 62.5 percent in
2012. The amount of recovered yard trimmings has increased from
negligible amount in 1960 to 57.7 percent in 2012. Recovered food waste
has increased less significantly from negligible amounts in 1960 to 4.8
percent in 2012.\83\
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\82\ U.S. EPA, Municipal Solid Waste Generation, Recycling, and
Disposal in the United States Tables and Figures for 2012. February
2014. http://www.epa.gov/waste/nonhaz/municipal/pubs/2012_msw_dat_tbls.pdf.
\83\ U.S. EPA, Municipal Solid Waste Generation, Recycling, and
Disposal in the United States Tables and Figures for 2012. February
2014. http://www.epa.gov/waste/nonhaz/municipal/pubs/2012_msw_dat_tbls.pdf.
---------------------------------------------------------------------------

Although material recovery has increased over time, states and
cities with vigorous recovery programs have proven that a greater
percentage recovery is possible. Organic waste diversion regulations
and zero waste programs are currently in effect in multiple U.S. states
and cities, with 183 municipalities providing separate curbside
collection of residential food waste.\84\ For example, state programs
in California, Connecticut, and Massachusetts focus on diversion from
commercial or certain multifamily residential waste
generators.^{85 86 87} Vermont's Universal Recycling Law
implements a phased material ban beginning in 2016 for leaf and yard
debris and food waste in 2020. City ordinances in New York City and
Portland, Oregon, mandate materials separation from commercial and
multifamily generators.^{88 89} Ordinances in Seattle and San
Francisco extend the separation mandate to single family
dwellings.^{90 91}
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\84\ Residential Food Waste Collection in the U.S. Biocycle.
54:3, 23, March 2013.
\85\ California Code of Regulations, title 14, division 7,
chapter 9.1, article 4, subarticle 6, section 18835, Mandatory
Commercial Recycling. http://www.calrecycle.ca.gov/recycle/commercial/
\86\ General Statutes of Connecticut, title 22a, chapter 446d,
sections 22a-226e, Recycling of Source-Separated Organic Materials.
http://cga.ct.gov/2014/sup/chap_446d.htm#sec_22a-226e
\87\ Code of Massachusetts Regulations, title 310 CMR 19.000.
January 2014 amendments. http://www.mass.gov/eea/docs/dep/service/regulations/wbreg14.pdf
\88\ City of Portland Administrative Rules, Business Solid
Waste, Recycling and Composting, ENN-2.06 http://www.portlandonline.com/auditor/?c=27430&a=294923.
\89\ Administrative Code of the city of New York. Title 16,
chapter 3, subchapter 2, section 1 (16-306.1). http://legistar.council.nyc.gov/LegislationDetail.aspx?ID=1482542&GUID=DDD94082-C0E5-4BF9-976B-BBE0CD858F8F.
\90\ San Francisco Environment Code. Chapter 19, sections 1901-
1912. Mandatory Recycling and Composting Ordinance. http://www.sfenvironment.org/sites/default/files/policy/sfe_zw_sf_mandatory_recycling_composting_ord_100-09.pdf.
\91\ Seattle Municipal Code. Chapters 21.40 and 21.76. http://www.seattle.gov/util/MyServices/FoodYard/BldgOwnersManagers_FoodYard/index.htm.

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[[Page 41788]]

In the 1996 Landfills NSPS Background Information Document (page 1-
25) the EPA ``decided not to include materials separation requirements
within the final rules because the EPA continues to believe RCRA and
local regulations are the most appropriate vehicle to address wide-
ranging issues associated with solid waste management for landfills.''
Although the EPA is not requesting input on mandating source
separation under the upcoming emission guidelines review, the EPA is
soliciting input and ideas for encouraging organic waste diversion
under the revised emission guidelines, including the specific
mechanisms described below and in section IV.E of this document or
other ideas in general.
One method to encourage organic waste diversion under the revised
emission guidelines is to provide rule exemptions for landfills
diverting 100 percent of organic wastes. The emission threshold
determination provisions currently in 40 CFR part 60, subpart WWW allow
non-degradable wastes to be excluded from the total waste mass when
computing the NMOC emission rate. If only non-degradable wastes were
accepted, then the waste inputs for the model would be zero, the
emission thresholds would not be exceeded, and thus GCCS would not be
required. The EPA solicits input on the methane emission reductions
from organic and inorganic waste diversion and whether adjustments
should be made to the annual NMOC reporting requirements for landfills
not accepting organic materials.
4. Encouraging New Technologies and Practices
The EPA understands that the technologies, BMPs, and source
separation practices discussed above can achieve reductions in
emissions from landfills. The EPA is seeking input on whether the use
of any of the technologies or practices discussed in this section in
conjunction with a well-designed and well-operated GCCS should be
considered as the EPA reviews the emission guidelines.
Section IV.E of this document discusses other mechanisms to
encourage wider use of these technologies and practices such as
emission threshold determination flexibilities.
5. Gas Control System Technology
Subpart WWW of 40 CFR part 60 currently requires all control
devices other than enclosed combustion devices to demonstrate 98-
percent reduction by weight of NMOC. Enclosed combustion devices have
the option of reducing emissions to 20 ppm, dry volume of NMOC, as
hexane. Both enclosed and non-enclosed flares as well as a suite of
other energy recovery devices are used to meet the control requirements
under the current regulatory framework.
Non-enclosed flares used at landfills meeting the criteria in 40
CFR 60.18(b) are thought to have destruction efficiencies similar to
enclosed flares and incinerators, and devices that burn LFG to recover
energy, such as boilers, turbines and internal combustion engines.
However, in April 2012 the EPA conducted an external peer review on
flaring efficiency and made available to the public a draft technical
report, ``Parameters for Properly Designed and Operated Flares.'' \92\
In the draft report, the EPA evaluated test data and identified a
variety of parameters that may affect flare performance and that could
be monitored to help assure good combustion efficiency. None of the
flare performance data used in the report comes from flares used at MSW
landfills, however, and the report does not provide any new test data
on non-assisted flare types, which to our knowledge, are the only non-
enclosed flare type found in this source category. Thus, while we have
no new information to suggest that flares at MSW landfills complying
with 40 CFR 60.18(b) will not achieve at least 98-percent destruction,
we solicit input and additional information on flare performance
specifically for this source category. Examples of information
requested for this source category include: Prevalence of flaring;
number and types of flares used; waste gas characteristics such as flow
rate, composition and heat content; use of flare gas recovery and other
flare minimization practices; and existing flare monitoring systems.
---------------------------------------------------------------------------

\92\ U.S. EPA, Parameters for Properly Designed and Operated
Flares, Report for Flare Review Panel, April 2012.
---------------------------------------------------------------------------

D. Alternative Monitoring, Reporting, and Other Requirements

In addition to the technologies, BMPs, and other approaches
discussed in section IV.C of this document, the EPA is considering
whether alternative monitoring and reporting requirements would be
appropriate for existing landfills. These alternative approaches
address concerns that have arisen in implementation of subpart WWW and
state and federal plans implementing subpart Cc and provide an
opportunity to increase the effectiveness of the regulation.
1. Wellhead Monitoring
The EPA is requesting public input on alternative wellhead
monitoring requirements. Commenters have expressed concerns about the
ability to consistently meet these parameters. One alternative
monitoring provision could be in the form of an exclusion from the
temperature and oxygen/nitrogen monitoring requirements, or a reduction
in the frequency of monitoring. For example, the EPA could reduce the
frequency of wellhead monitoring for these three parameters
(temperature and oxygen/nitrogen) from monthly to a quarterly or semi-
annual schedule. Owners or operators would continue to monitor the
wellhead for negative pressure.
The EPA is specifically requesting input on whether any such
adjustment should apply only to landfills that beneficially use LFG,
and if so whether there should be a threshold for the quantity of LFG
put to beneficial use above which sources would qualify for alternative
wellhead monitoring (and below which they would not), or whether the
beneficial use of any quantity of the recovered LFG should qualify for
alternative wellhead monitoring. Alternatively, the EPA is requesting
input on whether it would be more appropriate to require a certain
percentage of the overall recovered LFG to be beneficially used in
order to exempt landfills from or reduce the frequency of the wellhead
monitoring requirements.
If EPA were to limit adjusted monitoring to landfills that
beneficially use LFG, these alternatives could encourage new landfills
to beneficially use LFG. Both of these alternative options (exclusion
or reduced monitoring frequency) would provide monitoring relief to
these landfills. Landfill owners and operators must continue to operate
their GCCS in a manner that collects the most LFG and minimizes losses
of LFG through the surface of the landfill. In addition, landfills
would still have to prepare and submit to the regulating authority a
gas collection design plan, prepared by a professional engineer.
Subparts Cc and WWW of 40 CFR part 60 require landfill owners and
operators to operate each interior wellhead in the collection system
with a LFG temperature less than 55[deg]C and with either a nitrogen
level less than 20

[[Page 41789]]

percent or an oxygen level less than 5 percent. Compliance with these
requirements is demonstrated through monthly monitoring. Instead of
having the landfill owner or operator conduct monthly monitoring of
temperature and nitrogen/oxygen at the wellheads, the EPA is requesting
input on relying on landfill surface emission monitoring requirements
in combination with maintenance of negative pressure at wellheads to
indicate proper operation of the GCCS and minimization of surface
emissions. The potential removal of the temperature and nitrogen/oxygen
operational standards and associated wellhead monitoring requirements
for these three parameters would be complemented by the addition of the
surface monitoring provisions discussed in section IV.D.2 of this
document.
Given recent technological advancements in data storage and
transmission, the EPA is also considering an alternative to automate
the wellhead monthly monitoring provisions. Automation could reduce
long-term burden on landfill owner/operators as well as state
authorities by allowing for more frequent, but less labor-intensive,
data collection through the use of a system consisting of remote
wellhead sensors (i.e., thermistors, electronic pressure transducers,
oxygen cells) and a centralized data logger.
The use of continuous monitoring would allow more immediate
detection and repair. This would eliminate the time between when the
exceedance of the parameter occurs and when it is detected. It could
also improve enforceability of the rule by allowing inspectors to
review information on the data logger in real time during a site visit.
Another advantage to automating the monitoring is that it could provide
flexibility for incorporating additional parameters into the monitoring
program. The EPA is soliciting input on this alternative in general,
including: (1) The types of parameters that are best suited for an
automated monitoring alternative; (2) examples of successful automated
monitoring programs at MSW landfills and their associated costs; (3)
additional considerations for equipment calibration; and (4) input on
any averaging times that might be appropriate to determine when one or
more monitored parameters have been exceeded.
2. Surface Emissions Monitoring
The EPA is requesting input on potential alternative approaches to
the surface emission monitoring specified in 40 CFR part 60, subpart
WWW. Subpart WWW collection and control requirements are intended for
landfills to maintain a tight cover that minimizes any emissions of LFG
through the surface. The surface emissions monitoring procedures in
subpart WWW require quarterly surface emissions monitoring to
demonstrate that the cover and gas collection system are working
properly. The operational requirements in subpart WWW (40 CFR
60.753(d)) specify that the landfill must ``. . . operate the
collection system so that the methane concentration is less than 500
parts per million above background at the surface of the landfill. To
determine if this level is exceeded, the owner or operator shall
conduct surface testing around the perimeter of the collection area and
along a pattern that traverses the landfill at 30 meter intervals and
where visual observations indicate elevated concentrations of LFG, such
as distressed vegetation and cracks or seeps in the cover.''
Subpart WWW of 40 CFR part 60 includes provisions for increased
monitoring and corrective procedures if readings above 500 ppm are
detected. Instrumentation specifications, monitoring frequencies, and
monitoring patterns are structured to provide clear and straightforward
procedures that are the minimum necessary to assure compliance.
We are requesting public input on potential alternatives to the
surface monitoring procedures in 40 CFR part 60, subparts Cc and WWW.
Potential alternatives could include provisions such as those in the
California landfill methane regulation \93\ and include changing the
walking pattern for inspecting the surface of the landfill, adding an
integrated methane concentration measurement, and allowing sampling
only when wind is below a certain speed.
---------------------------------------------------------------------------

\93\ California Code of Regulations, title 17, subchapter 10,
article 4, subarticle 6, sections 95460 to 95476, Methane Emissions
from Municipal Solid Waste Landfills.
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We are requesting input on reducing the interval for the walking
pattern that traverses the landfill from 30 meters (98 ft.) to 25 ft.
We are also requesting input on the addition of an average methane
concentration limit of 25 ppm as determined by integrated surface
emissions monitoring. This would be in addition to the 500 ppm emission
concentration as determined by instantaneous surface emissions
monitoring. Integrated surface emissions monitoring provides an average
surface emission concentration across a specified area. For integrated
surface emissions monitoring, the specified area would be individually
identified 50,000 square foot grids. A tighter walking pattern and the
addition of an integrated methane concentration would more thoroughly
ensure that the collection system is being operated properly, that the
landfill cover and cover material are adequate, and that methane
emissions from the landfill surface are minimized. As part of these
potential changes, the EPA is also requesting input on not allowing
surface monitoring when the average wind speed exceeds 5 miles per hour
or the instantaneous wind speed exceeds 10 miles per hour because air
movement can affect whether the monitor is accurately reading the
methane concentration during surface monitoring. We are considering
this change because measurements during windy periods are usually not
representative of emissions.
We are also soliciting information and associated data on the cost
and assumptions for conducting enhanced surface monitoring as described
here. Several factors contribute to the cost of enhanced surface
monitoring. Monitoring along a traverse with a 25 ft. interval would
increase monitoring time, and, thus, the labor costs, compared to
monitoring along a 30 meter (98 ft.) interval. Monitoring along the
tighter traverse pattern would take approximately four times as long,
because the distance is approximately four times when covering a 50,000
square foot grid. For a landfill to conduct the integrated surface
emissions monitoring, the EPA assumes the landfill would rent a
handheld portable vapor analyzer with a data logger. The data logger
would be necessary to obtain an integrated reading over a single 50,000
square foot grid. However, the EPA does not expect that requiring an
integrated methane concentration would add significant cost because
landfills could use the same instrument that they currently use for the
instantaneous readings. These instruments can be programmed to provide
an integrated value as well as an instantaneous value.
The EPA recognizes that while these provisions could minimize
surface emissions, the actual reduction in emissions is difficult to
quantify. Surface monitoring is a labor intensive process and
tightening the grid pattern would increase costs. Thus, the EPA is
soliciting input on techniques and data to estimate the reductions
associated with enhanced surface monitoring.
The EPA is also requesting input on allowing the use of alternative
remote measurement and monitoring techniques for landfills that exceed
the surface monitoring concentrations in 40 CFR part 60, subpart Cc.
The EPA

[[Page 41790]]

would like information to determine whether to allow these alternative
techniques to be used to demonstrate that surface emissions are below
the specified methane surface concentrations. Alternative remote
measurement and monitoring techniques may include radial plume mapping
(RPM), optical remote sensing, Fourier Transform Infrared (FTIR)
spectroscopy, cavity ringdown spectroscopy (CRDS), tunable diode laser
(TDL), tracer correlation, micrometeorological eddy-covariance, static
flux chamber or differential absorption. The EPA is also seeking input
on the frequency of testing and the format of the standard if we allow
the use of these technologies as an alternative to average surface
concentrations as measured by Method 21. Incorporation of these
technologies would require a change in format of the standard to be
consistent with the technology.
3. Alternative Monitoring Provisions for LFG Treatment
The EPA is requesting input on defining treatment system as a
system that filters, dewaters and compresses LFG. This alternative
approach would be consistent with public commenters on previous
landfills documents (67 FR 36475, May 23, 2002; 71 FR 53271, September
8, 2006). It is also consistent with input from participants in
governmental outreach, who stated that the extent of filtration, de-
watering and compression can be site dependent, and that different
sites require different levels of gas treatment to protect the
combustion devices that use treated LFG as a fuel and ensure good
combustion. The alternative definition of treatment system would allow
the level of treatment to be tailored to the type and design of the
specific combustion equipment in which the LFG is used. If treatment
system was defined in this manner, owners/operators would need to
identify monitoring parameters and keep records that demonstrate that
such parameters effectively monitor filtration, de-watering or
compression system performance necessary for the end use of the treated
LFG.
Owners/operators would also need to develop a site-specific
treatment system monitoring plan that would not only accommodate site-
specific and end-use specific treatment requirements for different
energy recovery technologies, but would also ensure environmental
protection. Preparing the monitoring plan would document procedures
that landfills are likely already following to ensure that the LFG has
been adequately treated for its intended use.
The plan would be required to include monitoring parameters
addressing all three elements of treatment (filtration, de-watering,
and compression) to ensure the treatment system is operating properly
for the intended end use of the treated LFG. The plan would be required
to include monitoring methods, frequencies and operating ranges for
each monitored operating parameter based on manufacturer's
recommendations or engineering analysis for the intended end use of the
treated LFG. Documentation of the monitoring methods and ranges, along
with justification for their use, would need to be included in the
site-specific monitoring plan. In the plan, the owner/operator would
also need to identify who is responsible (by job title) for data
collection, explain the processes and methods used to collect the
necessary data, and describe the procedures and methods that are used
for quality assurance, maintenance, and repair of all continuous
monitoring systems.
The owner or operator would be required to revise the monitoring
plan to reflect changes in processes, monitoring instrumentation and
quality assurance procedures; or to improve procedures for the
maintenance and repair of monitoring systems to reduce the frequency of
monitoring equipment downtime. The EPA requests input on the definition
of treatment system and the creation of site-specific treatment system
monitoring plans.
4. Monitoring and Reporting Flexibility
Regulatory agencies and landfill owners and operators have
expressed concerns about the burden and response time of agencies
responsible for reviewing and approving design plans, Alternative
Compliance Timeline (ACT) requests, alternative remedies and higher
operating value (HOV) requests.
One way to minimize the need for such reviews would be to provide
more flexibility in wellhead monitoring provisions, as described in
section IV.D.1 of this document.
The EPA also solicits input on other ways to streamline the
monitoring, reporting and notification provisions as part of its review
of the emission guidelines. For example, currently the subparts Cc and
WWW of 40 CFR part 60 require site-specific design plan review and
approval procedures, recognizing the unique site-specific topography,
climate and other factors affecting the design of a GCCS. However, the
EPA solicits input on ways to streamline the design plan submission and
approval procedures as part of its review of the emissions guidelines.
Examples of streamlining may include the potential development of a
process by which approved alternative operating parameters could be
automatically linked to updates of design plans or development of a
process by which alternative operating parameters and updated design
plans could be approved on a similar schedule.
The EPA is also seeking input on the possibility of establishing a
third-party design plan certification program. The third-party program
would supplement or replace the current approach of requiring the EPA
or state review and approval of site-specific design plans and plan
revisions with a program by which independent third parties would
review the design plans, determine whether they conform to applicable
regulatory criteria, and report their findings to the approved state
programs or the EPA (for states without approved programs). The program
would be designed to ensure that the third-party reviewers are
competent, independent, and accredited, apply clear and objective
criteria to their design plan reviews, and report appropriate
information to regulators. Additionally, there would need to be
mechanisms to ensure regular and effective oversight of third-party
reviewers by the EPA and/or states that may include public disclosure
of information concerning the third parties and their performance and
determinations. Utilizing a third-party certification program could
help to standardize and expedite design plan reviews, and reduce the
burden on state regulators. The EPA is considering a broad range of
possible design features for such a program. Such features include
those discussed or included in several articles,^{94 95 96}
rules ^{97 98 99} and programs.^{100 101}
---------------------------------------------------------------------------

\94\ McAllister, Lesley K., Third-Party Programs to Assess
Regulatory Compliance, Presented at the Administrative Conference of
the United States, October 22, 2012.
\95\ Esther Duflo, et al., Truth-Telling By Third-Party Auditors
and the Response of Polluting Firms: Experimental Evidence From
India, 128 Quarterly Journal of Economics 4 at 1499-1545 (2013).
\96\ First Annual Oversight Report of the Decentralized Gateway
Vehicle Inspection Program, Missouri Department of Natural Resources
and the Missouri State Highway Patrol, 2008. http://www.dnr.mo.gov/gatewayvip/docs/enforcementrpt.pdf.
\97\ Renewable Fuel Standard program. http://www.epa.gov/OTAQ/fuels/renewablefuels/.
\98\ Wood Heater Compliance Monitoring Program. http://www.epa.gov/compliance/monitoring/programs/caa/woodheaters.html.
\99\ Mandatory Greenhouse Gas Emissions Reporting, California
Environmental Protection Agency. http://www.arb.ca.gov/cc/reporting/ghg-rep/ghg-rep.htm.
\100\ Massachusetts Department of Environmental Protection,
Third-Party Underground Storage Tank Inspection Program. http://www.mass.gov/eea/agencies/massdep/toxics/ust/third-party-ust-inspection-program.html.
\101\ Massachusetts Licensed Hazardous Waste Site Cleanup
Professional Program, http://www.mass.gov/eea/agencies/massdep/cleanup/licensed-site-professionals.html.

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[[Page 41791]]

We are considering the possibility of requiring sources to make
design plans (including revisions) available online and easily
accessible to the public as well as any impediment to doing so. We are
also seeking input on what constitutes a reasonable time period for
sources to make the design plans available online.
In addition to electronic storage of design plans, the EPA also
plans to include electronic reporting in the forthcoming proposal that
could amend subparts Cc and WWW of 40 CFR part 60 as a result of this
review.

E. Alternative Emission Threshold Determination Techniques

The EPA is considering adjusting the emission threshold
determinations that dictate when a GCCS must be installed, including
variations in the modeling parameters as well as adding site-specific
emission threshold determination. These alternatives may provide
additional reporting and compliance flexibilities for owners and
operators of affected landfills, including those that use new
technologies to increase oxidation of emissions, employ BMPs to
increase the effectiveness of GCCS, or increase organics diversion and
source separation practices.
1. Modeling Adjustments
An affected landfill currently has three different options (tiers)
for estimating whether the landfill exceeds the NMOC emission threshold
of 50 Mg per year. The simplest of these, the Tier 1 calculation
method, uses default values for the potential methane generation
capacity (L0) and methane generation rate (k) to determine
when the landfill exceeds the 50 Mg NMOC per year emission threshold.
The default L0 is 170 m\3\ per Mg of waste (equal to 5,458
cubic feet methane per ton of waste) and the k values are 0.05 per year
for areas receiving 25 inches or more of rainfall per year and 0.02 per
year for areas receiving less than 25 inches of rainfall. The Tier 1
default NMOC concentration is 4,000 parts per million by volume (ppmv)
as hexane. If the Tier 1 calculated NMOC exceeds 50 Mg per year, the
landfill must install controls or demonstrate, using more complex Tier
2 or 3 procedures, that NMOC emissions are less than 50 Mg per year.
A revised rule could allow for alternative Tier 1 default values
and modeling techniques based on the amount of organics in the waste.
For example, the L0 is a function of the moisture content
and organic content of the waste and L0 decreases as the
amount of organic matter decreases. Recent studies have shown that
average U.S. landfill L0 values have decreased 22 percent
between 1990 and 2012 (from 102.6 m\3\ per Mg of waste to 79.8 m\3\ per
Mg of waste) due to increased recovery of organic materials.\102\ A
revised rule could allow for landfill-specific L0 values to
be calculated based on the amount of degradable organic carbon (DOC),
similar to components of Equation HH-1 in the GHGRP for MSW landfills
(40 CFR part 98, subpart HH).
---------------------------------------------------------------------------

\102\ Stege, Alex. The Effects of Organic Waste Diversion on LFG
Generation and Recovery from U.S. Landfills. SWANA's 37th Annual
Landfill Gas Symposium. 2014.
---------------------------------------------------------------------------

Subpart HH of the GHGRP also provides separate k-values for
different types of materials, which could be used as alternate Tier 1
default values in revised emission guidelines. Sewage sludge and food
waste have the highest k values, followed by garden waste, diapers,
paper, textiles and wood and straw.\11\
The IPCC model employs a modeling method to accommodate separate k
and DOC modeling parameters as well as separate calculations for six
different categories of organic wastes.\103\
---------------------------------------------------------------------------

\103\ Intergovernmental Panel on Climate Change (IPCC), IPCC
Guidelines for National Greenhouse Gas Inventories. Volume 5
(Waste), Chapter 3 (Solid Waste Disposal). 2006.
---------------------------------------------------------------------------

If the EPA pursues incorporating alternative Tier 1 modeling values
in any revised emission guidelines, the EPA would also need to allow
for an alternative first-order decay model structure to compute a total
methane generation rate for the landfill based on the sum of the
methane generated from each separate waste stream. This alternative
model may incorporate material-specific k and L0 values,
instead of a single pair of k and L0 values applied to bulk
MSW. The EPA requests input on whether the alternative modeling
parameters and model structure in subpart HH of 40 CFR part 98, or
other default parameters or modeling procedures would be appropriate to
use for emission threshold determinations in revised emission
guidelines.
The EPA also requests input on whether such an alternative modeling
procedure would be limited to only those landfills that are employing
organic diversion or source separation.
2. Site-Specific Measurements
As indicated above, under the current emission guidelines, there
are three different tiers available to an affected landfill to estimate
whether the landfill exceeds the NMOC emission threshold of 50 Mg/yr.
If an affected landfill fails a Tier 2 test (i.e., the calculated NMOC
emissions are greater than 50 Mg/yr), then the landfill must conduct
Tier 3 testing or install and operate an active GCCS.
The EPA received input recommending the addition of a new Tier 4
surface emission monitoring (SEM) demonstration to allow increased
flexibility for landfills that exceed modeled NMOC emission rates if
they can demonstrate that site-specific methane emissions are actually
low. This SEM demonstration would be conducted using procedures similar
to those currently in 40 CFR part 60, subpart WWW (see 40 CFR
60.755(d)). If the monitoring finds that methane emissions are below a
level that the EPA adopts in the revised emission guidelines, then
installation of a GCCS could be delayed.
As an example, the California Air Resources Board (ARB) adopted the
Methane Emissions from MSW Landfills regulation in 2009.\104\ Under
this rule, if a landfill exceeds the waste-in-place and heat input
thresholds, the landfill may conduct an SEM demonstration prior to
being required to install a GCCS. If the measured surface methane
emissions exceed 200 ppm, the landfill must install a GCCS. This SEM
demonstration is similar to the Tier 4 option being considered by EPA.
---------------------------------------------------------------------------

\104\ California Code of Regulations, title 17, subchapter 10,
article 4, subarticle 6, section 95463, Methane Emissions from
Municipal Solid Waste Landfills.
---------------------------------------------------------------------------

The EPA is soliciting input about this new Tier 4 option or other
ideas for more flexible emission threshold determination ``Tiers'' and
what implementation procedures may be appropriate for each
determination. As the EPA takes this new Tier 4 option under
consideration, there are some implementation procedures that would need
to be established. The EPA requests input on all aspects of
implementing a new Tier 4 option, including the following specific
items: (1) Which areas of the landfill would be subject to SEM
requirements because these areas would no longer be limited to areas
with GCCS installed; (2) what number of exceedances over a specified
time period would require GCCS installation (40 CFR part 60, subpart
WWW specifies a new well must be installed at three or more exceedances

[[Page 41792]]

in a quarter); (3) what frequency of SEM demonstration (e.g., quarterly
monitoring for landfills accepting waste, annual monitoring for closed
landfills) is appropriate; (4) what exceedance level is appropriate for
determining if a GCCS must be installed (200 ppm or some other level);
and (5) whether the Tier 4 option would apply to all landfills that
could demonstrate surface emissions less than the determined exceedance
level, regardless of how this level was achieved; or, whether this
option would be made available to only those landfills employing and
maintaining oxidative cover practices, utilizing biofiltration cells,
or implementing other established best practices or organics diversion
programs as discussed later in this section.

F. Considerations for Implementation at Closed vs. Active Landfills

The landfills included as part of this review include landfills
that have accepted waste since November 8, 1987, and that commenced
construction, reconstruction or modification before July 17, 2014.
Table 3 of this document summarizes the closure patterns of the
approximately 1,800 landfills potentially affected by 40 CFR part 60,
subparts Cc and WWW.\105\
---------------------------------------------------------------------------

\105\ See Docketed Memorandum ``Summary of Landfill Dataset Used
in the Cost and Emission Reduction Analysis of Landfills
Regulations. 2014.''

Table 3--Age Distribution of Existing Landfills
----------------------------------------------------------------------------------------------------------------
All landfills Landfills with design capacity
---------------------------------- of 2.5 million Mg or greater
---------------------------------
When did landfill stop accepting waste? Number of Cumulative waste- Cumulative waste-
landfills in-place (tons) Number of in-place (tons)
in 2014 landfills in 2014
----------------------------------------------------------------------------------------------------------------
Before 1990 \a\............................. 33 84,300,000 10 63,200,000
Between 1990 and 1995....................... 335 662,300,000 62 465,500,000
Between 1995 and 2000....................... 242 583,300,000 56 429,500,000
Between 2000 and 2005....................... 97 402,300,000 29 343,000,000
Between 2005 and 2010....................... 82 310,900,000 27 250,500,000
Between 2010 and 2013....................... 77 469,800,000 31 408,400,000
N/A. Active as of 2014 \b\.................. 966 6,695,300,000 739 6,493,000,000
-------------------------------------------------------------------
Total................................... 1,832 9,208,200,000 954 8,453,100,000
----------------------------------------------------------------------------------------------------------------
\a\ But accepted waste after November 8, 1987.
\b\ Excludes model landfills that began operating in 2014 and are expected to be subject to the proposed subpart
XXX NSPS for MSW Landfills.

The EPA recognizes that existing landfills represent a wide range
of points in the life cycle of a typical landfill. Approximately 39
percent of the existing landfills (707/1,832) closed prior to 2005 and
those landfills collectively account for approximately 19 percent of
the total waste disposed through 2014. Because these wastes were
disposed of between 10 and 25 years ago, the LFG emission rates from
these older sites are decreasing and have a significantly smaller
contribution to emissions from this source category.
Given the wide range of points within a lifecycle that are
represented by potentially affected existing landfills, and recognizing
that some of the affected sites have not disposed of waste in over 25
years, the EPA believes that the implementation of any adjustments to
the current framework or incorporation of alternative control
frameworks or monitoring requirements may affect active landfills
differently than inactive landfills. Therefore, the EPA requests input
on how adjusting the current framework, selecting an alternative
framework or modifying the monitoring requirements should be evaluated
in terms of practicality, cost and emission reductions as these
adjustments affect landfills of various ages and activity levels.

G. Implementation Issues

Since the landfills emission guidelines were promulgated in 1996,
the EPA has become aware of a number of implementation issues for which
landfill owners and operators, as well as regulators, need
clarification. This section presents those issues and requests input on
those clarifications and potential resolutions.
1. LFG Treatment
In this document, the EPA is soliciting input on what constitutes
sufficient LFG treatment. In the Federal Register document proposing a
new subpart resulting from its review of the landfills NSPS (40 CFR
part 60, subpart XXX), the EPA refined a numeric definition of LFG
treatment and solicited input on a non-numeric definition that required
compression, dewatering, and filtration of LFG, as well as the creation
of a site-specific monitoring plan. The EPA requests input on whether a
non-numeric or numeric treatment requirement is appropriate for
landfills subject to the emission guidelines. Further, the EPA requests
input on whether previously proposed definitions of LFG treatment
should be adopted or if other approaches to LFG treatment should be
explored. We are also requesting input on expanding the use of treated
LFG fuel for a stationary combustion device, as some people have
previously interpreted this compliance option, but also include other
uses such as the production of vehicle fuel, production of high-Btu gas
for pipeline injection, or use as a raw material in a chemical
manufacturing process.
2. Closed Areas
To determine whether NMOC emissions from nonproductive areas of a
landfill are less than 1 percent of the total landfill NMOC emissions
(and hence controls are not required), the landfills regulations (40
CFR part 60, subparts Cc and WWW) rely on

[[Page 41793]]

modeled NMOC rates. To refine the measurements of these nonproductive
areas, the EPA is requesting input on allowing landfill owners or
operators to use either the measured or modeled flow of LFG to
determine if an area is nonproductive. The EPA is also requesting input
on what criteria and procedures would be considered acceptable for
making these estimates. The provisions would apply to physically
separated, closed areas of landfills.
3. Submitting Corrective Action Timeline Requests
If a landfill exceeds a wellhead operating parameter, the landfill
owner or operator must initiate corrective action within 5 days and
follow the timeline in 40 CFR part 60, subpart WWW for correcting the
exceedance. During implementation of subpart WWW, the question has been
raised whether a landfill needs agency approval of corrective action
timelines that exceed 15 calendar days but are less than the 120 days
allowed for installing a GCCS.
The EPA is seeking input on whether a specific schedule for
submitting these requests for alternative corrective action timelines
is appropriate because investigating and determining the appropriate
corrective action, as well as the schedule for implementing the
corrective action, will be site specific and depend on the reason for
the exceedance. We also solicit input on whether any clarifications
should be included in the revised emission guidelines to expedite the
submission of any alternative time line requests (i.e., as soon as they
know that they would not be able to correct the exceedance in 15 days
or expand the system in 120 days) to avoid being in violation of the
rule.
To address implementation concerns associated with the time allowed
for corrective action, the EPA requests input on an approach that
extends the requirement for notification from 15 days to as soon as
practicable, but no later than 60 days. Many requests for an
alternative compliance timeline express the need for additional time to
make necessary repairs to a well that requires significant construction
activities. Extending the time period to as soon as practicable but no
later than 60 days may reduce the burden and ensure sufficient time for
correction. If the EPA were to extend the time period, then the EPA
also would consider removing the requirement to submit an alternative
timeline for correcting the exceedance. Thus, by no later than day 60,
the landfill would have to either have completed the adjustments and
repairs necessary to correct the exceedance, or be prepared to have the
system expansion completed by day 120. The EPA is also requesting input
on whether 60 days is the appropriate amount of time that would allow
owners or operators to make the necessary a repairs.

V. Statutory and Executive Order Reviews

Under Executive Order 12866, titled Regulatory Planning and Review
(58 FR 51735, October 4, 1993), this is a ``significant regulatory
action'' because the action raises novel legal or policy issues.
Accordingly, the EPA submitted this action to the Office of Management
and Budget (OMB) for review under Executive Order 12866 and any changes
made in response to OMB recommendations have been documented in the
docket for this action. Because this action does not propose or impose
any requirements, other statutory and Executive Order reviews that
apply to rulemaking do not apply. Should the EPA subsequently determine
to pursue a rulemaking, the EPA will address the statues and Executive
Orders as applicable to that rulemaking.
Nevertheless, the EPA welcomes input and/or information that would
help the EPA to assess any of the following: The potential impact of a
rule on small entities pursuant to the Regulatory Flexibility Act (RFA)
(5 U.S.C. 601 et seq.); potential impacts on federal, state, or local
governments pursuant to the Unfunded Mandates Reform Act ((UMRA) (2
U.S.C. 1531-1538); federalism implications pursuant to Executive Order
13132, titled Federalism (64 FR 43255, November 2, 1999); availability
of voluntary consensus standards pursuant to section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (NTTAA),
Public Law 104-113; tribal implications pursuant to Executive Order
13175, titled Consultation and Coordination with Indian Tribal
Governments (65 FR 67249, November 6, 2000); environmental health or
safety effects on children pursuant to Executive Order 13045, titled
Protection of Children from Environmental Health Risks and Safety Risks
(62 FR 19885, April 23, 1997); energy effects pursuant to Executive
Order 13211, titled Actions Concerning Regulations that Significantly
Affect Energy Supply, Distribution, or Use (66 FR 28355, May 22,2001);
paperwork burdens pursuant to the Paperwork Reduction Act (PRA) (44
U.S.C. Sec. 3501); or human health or environmental effects on
minority or low-income populations pursuant to Executive Order 12898,
titled Federal Actions to Address Environmental Justice in Minority
Populations and Low-Income Populations (59 FR 7629, February 16, 1994).
The EPA will consider such comments during the development of any
subsequent rulemaking.

List of Subjects in 40 CFR Part 60

Environmental protection, Administrative practice and procedure,
Air pollution control, Reporting and recordkeeping requirements.

Dated: June 30, 2014.
Gina McCarthy,
Administrator.
[FR Doc. 2014-16404 Filed 7-16-14; 8:45 am]
BILLING CODE 6560-50-P