United States
Environmental Protection
Agency
Of lice of Air Quality
Planning and Standards
Research Triangle Park NC 27711
Air
EPA
Municipal Solid Waste Landfills:
Background Information
Document for National Emission
Standards for Hazardous Air
Pollutants
Public Comments and Responses
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EPA453/R-02-014
November2002
Municipal Solid Waste Landfills: Background Information Document
For National Emission Standards for Hazardous Air Pollutants
- Public Comments and Responses
U.S. Environmental Protection Agency
Office'of Air Quality Planning and Standards
Emission Standards Division
Research Triangle Park, North Carolina 27711
CO
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Disclaimer
This report has been reviewed by the Emission Standards Division of the Office of Air Quality
Planning and Standards, U.S. Environmental Protection Agency, and approved for publication
Mention of trade names or commercial products is not intended to constitute endorsement or
recommendation for use. Copies of this report are available through the Library Services Offices
(C267-01), U.S. Environmental Protection Agency, Research Triangle Park, N.C. 27711, (919)
541-2777, from National Technical Information Services, 5285 Port Royal Road, Springfield,
Virginia 22161, (703) 605-6000, or from the Internet (www.epa.gov/ttn).
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TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION 1
2.0 PUBLIC COMMENTS 2
2.1 LIST OF ACRONYMS AND ABBREVIATIONS 6
3.0 GENERAL COMMENTS 8
4.0 APPLICABILITY 9
5.0 MAJOR SOURCE DETERMINATION 18
6.0 SSM PLAN AND MONITORING REQUIREMENTS 25
7.0 HEALTH EFFECTS 26
8.0 PETROLEUM CONTAMINATED SOIL 27
9.0 MERCURY 31
10.0 BIOREACTORS 36
11.0 TITLE V 56
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1.0 INTRODUCTION
On November 7, 2000, the U.S. Environmental Protection Agency (EPA) proposed
national emission standards for hazardous air pollutants (NESHAP) for municipal solid waste
(MSW) landfills. The proposed rule fulfills the requirements of the Clean Air Act (CAA), which
requires EPA to regulate emissions of hazardous air pollutants (HAP) listed in section 112(b) of
the CAA. In addition, the proposed rule would help implement the Urban Air Toxics Strategy
devebped under section 112(k) of the CAA
This document contains summaries of the public comments that EPA received on the
November 7, 2000 proposal and the May 23, 2002 supplemental proposal to establish NESHAP
for MSW landfills. In this document, EPA responds to the public comments. This summary of
pub he comments and EPA responses serves as the basis for revisions made to the landfills
NESHAP between proposal and promulgation.
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2.0 PUBLIC COMMENTS
The EPA received 10 comment letters for the November 7, 2000 proposed rule before the
comment period closed on January 8, 2001. These comments are contained in category IV-D of
Docket A-98-28. Two "follow-up" documents were received after the January 8, 2001 deadline
as supplemental information for two of the ten original comment letters. These comments are
contained in category IV-G of the same docket. The EPA also received 12 comment letters
pertaining to the May 23, 2002 supplemental proposal for bbreactors. These comments are
contained in category IV-L of the same docket. The commenter, affiliation, and item number in
Docket A-98-28 are listed in Table 1. A list of acronyms and units of measure used in this
document appear after the list of commenters.
TABLE 1. DOCKET A-98-28
CATEGORY: IV-D
Item
Number Commenter and Affiliation
IV-D-01 S. Shah, P.E., Principal Environmental Engineer
Air Quality Permitting Program
Department of Environmental Protection
State of New Jersey (NJDEP)
Trenton, NJ
IV-D-02 E. J. SkernoKs, Director
Government Affairs
Waste Management, Inc.
Washington, D.C.
IV-D-03 D. J. Kolaz, Chief
Illinois Environmental Protection Agency
Springfield, Illinois
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TABLE 1. DOCKET A-98-28 (CONTINUED)
CATEGORY IV-D
Item
Number Commenter and Affiliation
IV-D-04 R. H. Co Iby, Chair
Air Toxics Committee
Association of Local Air Pollution Control Officials (ALAPCO)
and
B. L. Higgins, Chair
Air Toxics Committee
State and Territorial Air Pollution Program Administrators (STAPPA)
Washington, D.C.
IV-D-05 J. H. Skinner, PhD.
Executive Director and Chief Executive Officer
The Solid Waste Association of North America (SWANA)
Silver Spring, MD
IV-D-06 D.C. Foerter, Deputy Director
Institute of Clean Air Companies (1C AC)
Washington, D.C.
IV-D-07 E.W. Repa, Ph.D., Director
Environmental Programs
The National Solid Wastes Management Association (NSWMA)
Washington, D.C.
IV-D-08 F.R. Caponi, Supervising Engineer
Solid Waste Management
County Sanitation Districts of Los Angeles County
Whittier, CA
IV-D-09 E. L. Munsell, Deputy Assistant
Secretary for Environment and Safety
Department o f the Navy
Washington, D.C.
IV-D-10 R. J. Phaneuf, C hair
Bioreactor Landfill Work Group
Association of State and Territorial Solid Waste Management Officials
(ASTSWMO)
Washington, D.C.
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TABLE 1. DOCKET A-98-28 (CONTINUED)
CATEGORY IV-G
Item
Number Commenter and Affiliation
IV-G-01 S. Shah, P.E., Principal Environmental Engineer
(follow-up to Air Quality Permitting Program
IV-D-01) Department of Environmental Protection
State of New Jersey (NJDEP)
Trenton, NJ
IV-G-02 D. Newton, HAP Subcommittee Chair
(follow-up to Naval Facilities Engineering Service Center
IV-D-09) Department o f the Navy
Port Hueneme, CA
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TABLE 1. DOCKET A-98-28 (CONTINUED)
CATEGORY IV-L
Item
Number Commenter and Affiliation
IV-L-01 T. Tweedale
Montana Coalition for Health, Environmental & Economic Rights
Missoula, MT
IV-L-02 R. J. Phaneuf, C hair
Bioreactor Landfill Work Group
Association of State and Territorial Solid Waste Management Officials
(ASTWSMO)
Washington, B.C.
IV-L-03 J. H. Skinner, PhD.
Executive Director and Chief Executive Officer
The Solid Waste Association of North America (SWAN A)
Silver Spring, MD
IV-L-04 S. Hammond, P.E., Director
Division of Solid & Hazardous Materials
New York State Department of Environmental Conservation
Albany, NY
IV-L-05 M. S. GilKland, Manager
Solid Waste Policy and Program Development
Oregon Department ofEnvironmental Quality
Portland, OR
IV-L-06 E.W. Repa, Ph.D., Director
Environmental Programs
The National Solid Wastes Management Association (NS WMA)
Washington, D.C.
IV-L-07 E. J. SkernoKs, Director
Government Affairs
Waste Management, Inc.
Washington, D.C.
IV-L-08 R. F. Hasemeier, P.E.
Senior Solid Waste Engineer
Gannett Fleming, Inc.
Harrisburg, PA
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TABLE 1. DOCKET A-98-28 (CONTINUED)
CATEGORY IV-L
Item
Number Commenter and Affiliation
IV-L-09 M. Hudgins, Vice President
Landfill Technology Division
Environmental Control Systems, Inc.
Aiken, SC
IV-L-10 S. R. Wymbs, Executive Director
Cumberland County Improvement Authority
Mfflvflle, NJ
IV-L-11 H. Pak
Trinet Industries, Inc.
Walnut, CA
IV-L-12 J. M. Becker, P.E.
Smith Management Group
Louisville, KY
2.1 LIST OF ACRONYMS AND ABBREVIATIONS
Acronyms
CAA Clean Air Act
CEMS continuous emission monitoring systems
CFR Code of Federal Regulations
EG emission guidelines
EPA Environmental Protection Agency
FR Federal Register
GACT generally available control technology
HAP hazardous air pollutants
m3 cubic meters
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MACT maximum available control technology
Mg mega grams
Mg/yr megagrams per year
MSW municipal solid waste
NESH AP national emission standards for hazardous air pollutants
NMOCnonmethane organic compounds
NSPS new source performance standards
PCS petroleum contaminated soil
ppm parts per million
RCRA Resource Conservation and Recovery Act
RD&D research, development, and demonstration
SSM startup, shutdown, and malfunction
tpy tons per year
VOC volatile organic compounds
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3.0 GENERAL COMMENTS
Comment: Many commenters (IV-D-02, IV-D-07, IV-D-06, IV-D-08, IV-D-05) support
EPA's proposed approach for applying maximum available control technology (MACT) standards
to MSW landfills. One commenter (IV-D-07) believes EPA has taken a reasonable approach to
the proposed rule given the unique nature of landfills as a source category and the current state of
landfill gas control technology. One commenter (IV-D-06) stated that since the NESHAP
emission control requirements are already in effect under the emission guidelines/new source
performance standards (EG/NSPS), the proposed NESHAP has already been proven to be
technologically sound and fundamentally reasonable. Other commenters (IV-D-05, IV-D-08)
stated that the proposed NESHAP affirms that the EG/NSPS requirements represent the most
stringent control for HAP currently available. One commenter (IV-D-02) agrees with EPA that
emissions control beyond those established by the EG/NSPS are not warranted.
Response: The EPA appreciates the commenters' support. The EPA continues to follow
the requirements of the CAA in devebping the final landfills NESHAP.
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4.0 APPLICABILITY
Comment: One commenter (IV-D-09, IV-G-02) suggested that the language in §63.1935
be revised to prevent the NESHAP from extending part 60 control requirements to landfifls that
do not meet the control device applicability thresholds of 40 CFR part 60, subparts Cc and WWW
(EG/NSPS). The commenter (IV-D-09, IV-G-02) considered the current language to be
problematic because it implies that small landfills that would otherwise be area sources, but are
collocated on major source facilities, become subject to EG/NSPS control even though they do
not meet control criteria established in 40 CFR part 60. The commenter (IV-D-09, IV-G-02)
believes that it would be unreasonable to control landfills that do not meet the capacity and
emission criteria that trigger emission control in40 CFR part 60. The commenter (IV-D-09,
IV-G-02) stated that many military facilities which are major HAP sources have small, often
closed, MSW landfills which are not subject to emission control. The commenter (IV-D-09,
IV-G-02) provided EPA with a list of military major HAP source installations that have MSW
landfills that have accepted waste since November of 1987 and are not subject to the EG/NSPS.
The commenter (IV-D-09, IV-G-02) believes that EPA should not allow the rule to impact such
facilities since EPA did not anticipate such impacts.
Response: At the time of proposal, EPA was uncertain of whether there were small
landfills collocated at major sources. While the NESHAP applies to all major sources, it was not
EPA's intent to require collection and control systems at landfills that are too small to meet the
control criteria in the EG/NSPS. Because the EG/NSPS forms the MACT floor for landfills the
NESHAP requires all major sources, including collocated sources, to comply with the EG/NSPS.
However, the additional provisions of the NESHAP do not take effect until control is required by
the EG/NSPS. The EPA revised §63.1935 to clarify the applicability of the NESHAP to major
sources, area sources, and smaller landfills that are collocated with major sources. The
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cornmenter correctly points out that some small landfills, including military facilities, will be
subject to the landfills NESHAP as a result of being collocated with a major source. Landfills
with design capacities less than2.5 million megagrams (Mg) or 2.5 million cubic meters (m3) that
are subject to the NESHAP because they are collocated with major sources comply with the
NESHAP by complying with the NSPS or the Federal plan or EPA-approved and effective State
or tribalplan that implements the EG. The only requirement of the NSPS, Federal plan, or State
or tribal plan for such landfills is submittal of an initial design capacity report. The NESHAP does
not extend collection and control requirements to landfills that do not meet the control device
applicability thresholds of the EG/NSPS or impose additional requirements for such landfills.
Sections 63.1945 and 63.1955 have been revised to clarify that the additional requirements of the
NESHAP only apply when the landfill is required to install a collection and control system by the
NSPS or the Federal, State, or tribal plan that implements the EG.
Comment: Two commenters (IV-D-07, IV-D-02) recommended that additional MACT
requirements should not apply unless and until the site is determined to be meeting or exceeding
the major source threshold of 10 tons per year (tpy) for a single HAP or 25 tpy for combination of
HAP. One of the commenters (IV-D-02) recommended EPA require no control for area sources
(i.e., not require area sources with EG/NSPS controls to meet the NESHAP general provisions
and additional recoidkeeping requirements) because larger area source landfills subject to
EG/NSPS control requirements emit no more HAP than smaller uncontrolled landfills.
Response: The EPA intends that the landfills NESHAP apply to area sources that are
subject to EG/NSPS control requirements (i.e., have design capacities of 2.5 million Mg and
2.5 million m3 or more, and estimated uncontrolled nonmethane organic compounds (NMOC)
emissions of 50 megagrams per year (Mg/yr) or more). Therefore, EPA has not changed the rule
in response to this comment. Regulation of area source landfills is required under section 112(k)
as part of the Urban Air Toxics Strategy. Area sources may be controlled using MACT or
generally available control technology (GACT), and EPA chose to regulate landfill area sources
using GACT. For area source landfills that are 2.5 million Mg and 2.5 million m3 or greater in
design capacity and have estimated uncontrolled NMOC emissions of 50 Mg/yr or more
(calculated according to procedures in the EG/NSPS), EPA selected GACT to be the same as
MACT. The EG/NSPS already covers these sources, so requiring GACT does not impose
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additional control requirements. The only burden imposed on these sources by the NESHAP are
some additional compliance determination and reporting requirements that are necessary under
section 112 general provisions. These include startup, shutdown, and malfunction (SSM)
provisions, use of continuous parameter monitoring data to determine compliance with the
operating condition requirements, and reporting of deviations every 6 months as opposed to every
year. The monitoring instruments, frequency of monitoring and required records of monitoring
data are not different from the EG/NSPS, so the monitoring costs do not increase. The use of the
monitoring results to determine compliance and the semiannual reports better assure continuous
compliance and improve the enfbrceability of the NESHAP at minimal cost.
For MS W landfills smaller than 2.5 million Mg or 2.5 million m3 design capacity, or that
have estimated uncontrolled NMOC emissions less than 50 Mg/yr and are not bioreactors, GACT
is determined to be no control. Requiring these landfills to control emissions would result in
additional and unreasonable control costs because these smaller landfills are not required to install
controls by the EG/NSPS. These landfills are costly to control and emit relatively little HAP.
Furthermore, the design capacity cutoff excludes those landfills least able to afford collection and
control systems, for example, small businesses, and particularly, municipalities. See the proposal
preamble (65 FR 66677, November 7, 2000) for additional discussion of area source landfills.
Note that the bioreactor portion of the NESHAP applies to major and area sources that
equal or exceed the EG/NSPS design capacity criteria of 2.5 million Mg and 2.5 million m3 and
operate as a bioreactor, regardless of whether they exceed the EG/NSPS 50 Mg/yr uncontrolled
emission rate criteria. See Chapter 10 of this document for comments and responses regarding
rule applicability and control requirements for bioreactors.
Comment: One commenter (IV-D-09) recommended that the statement in §63.1935 that
states, "...Finally, most of the requirements of this subpart will not take effect until your landfill
emits equal to or greater than 50 Mg/yr NMOC and has a design capacity equal to or greater than
2.5 million Mg and 2.5 million m3" be deleted. The commenter (IV-D-09) pointed out that the
wording implies that there are some NESHAP requirements for landfills that do not exceed the
emission rate and design capacity criteria. However, the commenter (IV-D-09) states that if a
landfill does not exceed all of the stated criteria, it is not subject to control requirements and the
NESHAP should not apply.
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Response: The EPA revised §§63.1935 and 63.1945 to clarify the applicability of the
NESHAP to major sources, area sources, and smaller landfills that are collocated with major
sources. Major source landfills are subject to the landfills NESHAP and must comply with
requirements imposed bythe landfills NESHAP (§§63.1960 through 63.1980), which are
described in the proposed rule. Smaller landfills that are collocated with major sources but fall
below the EG/NSPS design capacity criteria of 2.5 million Mg and 2.5 million m3 are subject to
the landfills NESHAP. These smaller landfills that are collocated with major sources comply with
the NESHAP by complying with the NSPS or the Federal, State, or tribal plan that implements
the EG. These landfills are subject to reporting requirements of the NSPS, Federal, State, or
tribal plan (such as the design capacity report), but are not required to install a collection and
control system or to comply with the additional NESHAP requirements. Similarly, conventional
landfills collated with major sources that exceed the EG/NSPS design capacity criteria but have
estimated uncontrolled NMOC emissions less than 50 Mg/yr would need to comply with the
NSPS or the Federal, State or tribal plan requirements, such as periodically calculating annual
emissions, but would not be required to install a collection and control system or to comply with
the additional NESHAP requirements until they are required to install control systems under the
EG/NSPS. (Note that timely control is required for bioreactor landfills with design capacities
equal to or greater than 2.5 million Mg and 2.5 million m3, as explained in the supplemental
proposal (67 FR 36460) and in Chapter 10 of this document.)
Area source landfills that fall below the NSPS design capacity and emissions criteria are
not subject to the landfills NESHAP, but would follow the requirements of the NSPS or the
Federal, State, or tribal plan that implements the EG. Area sources with design capacities greater
than or equal to 2.5 million Mg and 2.5 million m3 and that have estimated uncontrolled NMOC
emissions of 50 Mg/yr or more (or are bioreactors) are subject to the NESHAP. They must
install a collection and control system under the NSPS, Federal, State, or tribal plan and comply
with the additional requirements imposed bythe NESHAP (§63.1960 through §63.1980).
Applicability and control requirements for landfills with bioreactors have also been clarified. The
applicability criteria for landfills with bioreactors in §63.1935 have been reworded since proposal
to clarify that all major sources, all landfills collocated with major sources, and area sources
meeting specified criteria are subject to the NESHAP. However, as specified in §§63.1947 and
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63.1955(d), the requirements for timely control ofbioreactors apply only to landfills that were
active as of the promulgation date and have design capacities equal to or greater than 2.5 million
Mg and 2.5 million m3, consistent with the supplemental proposal (67 FR 36460). See the
supplemental proposal and the comment responses in Chapter 10 of this document.
Comment: One commenter (IV-D-09) recommended the revision of §63.1955, which
states: "(b) If you are required by §60.752(b)(2) of 40 CFR part 60, subpart WWW, the Federal
plan, EPA approved State or tribal plan, to install a collection and control system, you must
comply with the general pro visions specified in Table 1 of this subpart." The commenter
(IV-D-09) suggested the section read, "When you are required in paragraph (a) of this section to
install a collection and control system, you must comply with the general provisions specified in
Table 1 of this subpart." The commenter (IV-D-09) recommended this change because language
in section II.D of the preamble and proposed §63.1950 suggest that if controls are not required by
the EG/NSPS, then the NESHAP doesn't apply. The commenter (IV-D-09) suggested the
language changes in order to clarify requirements for small landfills collocated with major sources
and to avoid applicability contradictions within the text.
Response: The EPA has not made the specific wording change suggested by the
commenters, but has clarified the rule to address the issues raised. Clarifications made regarding
applicability of the NESHAP to major sources, landfills collocated at major sources, and area
sources are described in previous responses.
The general provisions in Table 1 and the specific requirements in §§63.1960 through
63.1980 apply to the landfills that must install a collection and control system under the NSPS or
the Federal, State, or tribal plan that implements the EG. Therefore, EPA added language to
§63.1955 to clarify that landfills that are required to install a collection and control system under
the NSPS or the Federal, State, or tribal plan that implements the EG must also meet the
requirements in §63.1960 through §63.1980 of the NESHAP. The EPA has also clarified, in
§63.1945, the timing of when the additional NESHAP requirements apply. New affected sources
must comply with the NESHAP by the date the final rule is published or at the time operation
begins, whichever is last. The NESHAP requires the landfill to comply with the NSPS. at that
time. A landfill that is a new affected source must meet the additional requirements of the
NESHAP that are over and above the NSPS (e.g. SSM requirements, semiannual reporting
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requirements) on the date the landfill is required to install a collection and control system by the
NSPS. Existing affected sources must comply with the NESHAP by 1 year after publication of
the final rule. The NESHAP requires the landfill to comply with the NSPS or Federal, State or
tribal plan that implements the EG (whichever applies to the landfill) at that time. The landfill
must comply with the additional requirements of the NESHAP by the date the landfill is required
by the NSPS or Federal, State or tribal plan to install a collection and control system or by the
date 1 year after publication of the final NESHAP, whichever is later. Section 63.1950, which has
not been changed, clarifies that the NESHAP requirements no longer apply once a landfill has met
the EG/NSPS criteria for control system removal and is no longer required to control emissions.
The timing of control system installation and removal for bioreactors has also been clarified. See
the comment responses in Chapter 10 of this document.
Comment: One commenter (IV-D-09) suggested deleting the language in §63.1940 that
defines an affected source as "each new or existing MSW landfill that has accepted waste at
anytime since November 8,1987, or has additional design capacity available for future waste
deposition." The commenter (IV-D-09) considered this language to contradict the preamble and
§63.1935. The commenter (IV-D-09) stated that the November 8, 1987 criteria should be used
for determining if a landfill is subject to control requirements under part 60 and the NESHAP, but
by no means should it be used as the sole criteria for defining an affected source. Instead, the
commenter (IV-D-09) suggested that the affected source should be one that meets all of the waste
acceptance, design capacity and emission rate criteria.
Response: The EPA revised §§63.1935 and 63.1940 to clarify the applicability and
identify the affected source of the NESHAP. The affected source is the entire MSW landfill in a
contiguous geographical space where household waste is placed in or on the land and consists of
one or more cells that are under common ownership or control. The facility may receive
household waste as well as other types of Resource Conservation and Recovery Act (RCRA)
Subtitle D waste. The affected source may be operated as a conventional landfill, or it may be
operated completely or partially as a bioreactor. To be an affected source, the landfill must have
accepted waste since November 9, 1987, or have additional capacity for waste deposition, and
must be either: (1) a major source of HAP; (2) collocated with a major source of HAP; or (3) an
area source with a design capacity greater than or equal to 2.5 million Mg and 2.5 million m3 and
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with estimated uncontrolled NMOC emissions of equal to or greater than 50 Mg/yr. To be an
affected source, a landfill that includes a bioreactor (as defined in the NESHAP) must meet the
criteria in(l) or (2) listed above or be an area source landfill that has a design capacity equal to or
greater than 2.5 million Mg and 2.5 million m3, and is not permanently closed as of the date the
final NESHAP is published. (See Chapter 10 of this document for further information on
requirements for bbreactors.)
Comment: Two commenters (IV-D-05, IV-D-08) noted that the EG/NSPS for landfills
incorporates language allowing for alternatives from specific rule requirements. The commenters
(IV-D-05, IV-D-08) stated that in the proposed NESHAP, it is not clear if any alternatives
granted to a landfill operator under the EG/NSPS would also be in compliance with the proposed
NESHAP. For this reason, the commenters (IV-D-05, IV-D-08) expressed concern that some
landfiflsmay be in compliance with local permits incorporating the EG/NSPS through state
delegation, but would be out of compliance with the proposed NESHAP. The commenters
(IV-D-05, IV-D-08) suggested that the proposed NESHAP be modified to include a specific
clarification of this issue.
Response: The EPA intended to allow alternatives approved under the EG/NSPS to be
allowed under the NESHAP. This includes, for example, alternative collection system designs
and monitoring and reporting requirements approved under §60.752(b)(2) of Subpart WWW.
However, afl landfills that are subject to the NESHAP and required to use collection and control
systems must meet the SSM requirements and must submit reports of deviations every 6 months.
The rule language has been clarified regarding approved alternatives.
Comment: Two commenters (IV-D-07, IV-D-02) stated that the preamble suggests that
landfills have no MACT requirements until the gas collection and control system is installed,
under the EG/NSPS. Thecommenters (IV-D-07, IV-D-02) cited instances in which landfill
owners/operators have installed and are operating landfill gas systems for reasons other than
EG/NSPS, such as the control of gas migration or the protection of ground water, etc. The
commenters (IV-D-07, IV-D-02) recommended that the proposed NESHAP be revised to clearly
indicate that MACT requirements are not applicable until the date a landfill is required to install a
collection and control system under the EG/NSPS.
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Response: The EPA agrees with the commenters that most of the requirements of the
NESHAP are not implemented until a collection and control system is installed under the
EG/NSPS. The EPA expressed this intent in section III.H of the proposal preamble, which states,
"...the additional requirements do not go into effect until a landfill has met the collection and
control applicability criteria of the EG/NSPS." In response to these comments, EPA revised
§§63.1935 through 63.1945 of the rule to clarify the applicability and timing of regulatory
requirements. The landfill is subject to the NESHAP at the same time as specified in the
proposal. At that time it is required to comply with the NSPS or the Federal, State, or tribal plan
that implements the EG. The revised §63.1945 clarifies that new affected sources must comply
with the additional NESHAP requirements (including the SSM plan, compliance determination,
and semiannual reporting requirements) on the date the landfill is required to install a collection
and control system under the NSPS. Existing affected sources must comply with the additional
NESHAP requirements on the date the landfill is required to install a collection and control
system under the NSPS or the Federal plan or EPA-approved State or tribal plan that implements
the EG or by the date 1 year after publication of the final NESHAP, whichever is later. A
separate section (§63.1947) explains the compliance dates for bioreactors.
Comment: One commenter (IV-D-03) requested clarification of the un-defined term
"collocated", which is used in §63.1935.
Response: The EPA considers the term "collocated" to refer to landfill cells and other
equipment and activities that are under common ownership or control and which occupy a single
contiguous area A contiguous area includes an area divided by a road, power right of way, or
golf course, for example. The EPA believes that the term "collocated" in connection with source
definitions under the CAA is commonly used and understood, and does not believe a definition
unique to the landfill rule is necessary.
Comment: One commenter (IV-D-03) observed that proposed §60.1935, though entitled,
"Am I subject to this subpart?" defined not only who the rule applies to, but also requires
owners/operators to obtain title V permits for area landfill sources. The commenter (IV-D-03)
recommends that a separate section titled "What requirements apply to area sources?" be added.
Response: The EPA has removed from §63.1935 the language requiring
owners/operators of area source landfills to obtain title V permits. The rationale for deleting this
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language and responses to other comments related to title V are contained in Chapter 11 of this
document.
Comment: One commenter (IV-D-04) expressed concern with the "once in, always in"
policy related to MACT standards. The commenter (IV-D-04) stated that the policy presents
obstacles to some sources interested in reducing emissions through pollution prevention. The
commenter (IV-D-04) recommended that EPA include provisions in the MS W landfill NESHAP
clarifying that the "once in, always in" policy will not apply in certain qualifying cases. The
commenter (IV-D-04) identified qualifying sources as those subject to a MACT standard that
subsequently implement pollution prevention technologies that provide emission reductions no
less than those required under the MACT standard.
Response: This comment appears to be written as a policy question about MACT
standards in general, and does not include a specific comment relating to the NESHAP for MSW
landfills. Without any clarifying information explaining how pollution prevention might be appKed
to landfills, EPA is unable to address the concern directly. As a result, EPA is not changing the
landfills NESHAP in response to this comment.
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5.0 MAJOR SOURCE DETERMINATION
Four commenters (IV-D-05, IV-D-08, IV-D-07, IV-D-02) believe that EPA
overestimated the number of major source landfills. Two commenters (IV-D-05, IV-D-08)
disagree with how EPA determined the number of major source landfills and requested that EPA
reevaluate its determination of the number of major source landfills. Commenters (IV-D-05,
IV-D-08, IV-D-07, IV-D-02) contended that only a small number of landfills should be
considered as major source landfills for three reasons: (1) AP-42 emission factors are incorrect
and overestimate landfill gas emissions; (2) EPA should have considered EG/NSPS controls when
determining whether a landfill is a major source; and (3) using NMOC as a surrogate for HAP is
arbitrary and EPA changed the definition of major source. Each of these three comments is
summarized and addressed individually in this section.
Comment: Several commenters (IV-D-05, IV-D-08, IV-D-07, IV-D-02) stated that the
AP-42 emission factors are incorrect and overestimate landfill gas HAP emissions. Commenters
(IV-D-05, IV-D-08, IV-D-07, IV-D-02) stated that the factors contribute to EPA's
overestimation of the number of major source landfills in the nation. Commenters (IV-D-05,
IV-D-08) are concerned that the overestimated AP-42 values could potentially misdirect EPA in
establishing policy for MSW landfills.
Two of the commenters (IV-D-02, IV-D-07) recommend that EPA undertake a complete
revision of the AP-42 emission factors as the basis for any final regulations. Two other
commenters (IV-D-05, IV-D-08) requested that EPA revise the AP-42 defaults to reflect the
current LFG constituent levels. Two commenters (IV-D-05, IV-D-02) provided, and other
commenters (IV-D-08, IV-D-07) referred to, a report, 'Waste Industry Air Coalition Comparison
of Recent Landfill Gas Analyses with Historic AP-42 Values." They claim the report shows that
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the AP-42 defaults typically overestimate current concentrations of individual organic HAP
compounds in landfill gas.
Commenters (IV-D-02, IV-D-07) stated that the methane emission generation models may
be inaccurate in predicting NMOC, and therefore, do not accurately predict HAP emissions. The
commenters (IV-D-02, IV-D-07) stated that generation curves for NMOC and methane are
different because NMOC emissions generally decline more rapidly than methane emissions over
time, but the model predicts constant NMOC concentrations over time. They also contend that
the model does not take into account the attenuating effect of the landfill cover.
Response: The EPA used the current version of AP-42 to estimate the number of MSW
landfills that are major sources of HAP. AP-42 and the associated Landfill Gas Emissions Model
contain the accepted and approved emission factors and the best methods currently available for
estimating landfill gas emissions.
The EPA is aware of the report submitted by the commenters. The EPA Emission Factor
and Inventory Group, the EPA program responsible for AP-42 emission factors, is reviewing the
report and technical data, and EPA is undertaking a landfill testing program to collect additional
HAP data. There is very limited technical information about the difference in the decline of
NMOC vs. methane and some of the information disagrees with the commenter's claims. There is
also very limited data on any effects of cover design on emissions, but it is reasonable to assume
that cover design does not change the total amount of gas and NMOC generated through the
decomposition of waste in the landfill. When EPA updates the AP-42 chapter on landfill
emissions, EPA will consider all relevant data. However, EPA's Emission Factor and Inventory
Group could not complete their data collection and analysis prior to promulgation of the final
landfills NESHAP.
The EPA used the current version of AP-42 in developing the landfills NESHAP. Any
update of AP-42 or adjustment of calculation procedures would not affect EPA regulatory
decisions in developing the landfills NESHAP. The EPA found that the MACT floor is the
EG/NSPS level of control. This floor is based on the current level of control at major and
synthetic area sources and would not change if there are somewhat fewer or more major sources
than previously estimated.
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Comment: Severalcommenteis (IV-D-05, IV-D-08, IV-D-07, IV-D-02) disagree with
determining whether a landfill is a major source by calculating uncontrolled emissions, because the
EG/NSPS requires control. Two commenters (IV-D-05, IV-D-08) cited the definition of major
source in the CAA and noted that the definition directs EPA to consider controls. Commenters
(IV-D-02, IV-D-07) stated that because the EG/NSPS are Federal requirements, EPA must take
into account the EG/NSPS control requirements before determining a landfill's potential to emit.
Commenters (IV-D-05, IV-D-08, IV-D-07, IV-D-02) stated that EPA should estimate potential
emissions after EG/NSPS control and compare that to the lOtpy single HAP/25 tpy combination
of HAP criteria to determine which landfills are major sources. Two commenters (IV-D-05,
IV-D-08) understand that the proposed requirements are the same for both major and for select
area sources, but the commenters stressed the importance to apply the proper designation to
landfills, so that other rulemaking activities that may distinguish between major or area sources
are implemented correctly. These two commenters (IV-D-05, IV-D-08) believe that if EPA does
not properly designate major and area source landfills, there could be unnecessary landfill
regulations in the future. Onecommenter (IV-D-02) attached a copy of a 1999 memo to EPA
calculating that there are few major sources if EG/NSPS controls and Waste Industry Air
Coalition HAP concentrations (see previous comment) are taken into account.
Response: The EPA agrees that when determining whether a landfill is a major source,
there are relatively few landfills that would be considered major sources of HAP because most of
the large landfills have Federally-enforceable controls required by the EG/NSPS and therefore
emit less than 10 tpy individual HAP or 25 tpy combination of HAP. The preamble to the
proposed rule may have led commenters to believe that EPA considers 1,140 landfills to be major
sources of HAP: "We estimated that 1,140 facilities are, or will be, major sources of HAP." This
statement is unclear. The EPA's intent was to state that based on estimates of maximum
uncontrolled emissions, 1,140 landfills have potential emissions greater than 10 tpy individual
HAP or 25 tpy combination of HAP. The EPA does not believe that actual landfill gas emissions
from each of these 1,140 landfills exceeds 10 tpy individual HAP or 25 tpy combination of HAP,
but in determining the MACT floor, EPA must consider maximum uncontrolled emissions from
landfills.
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In determining the MACT floor, the CAA requires EPA to identify the best-controlled
sources in a category. The population of landfills that EPA used to determine the MACT floor
was landfills with uncontrolled emissions greater than 10 tpy individual HAP or 25 tpy
combination of HAP. This population includes both major and "synthetic area" sources. A
synthetic area source is a source that would otherwise be a major source if not for emission
controls that have been installed. Synthetic area sources have the same emission characteristics
as major sources (ie., size, waste composition, age), but are equipped with emission collection
and control systems that have been demonstrated to be effective in reducing HAP emissions.
Synthetic area sources were included in the MACT floor population because the feasibility of
applying landfill controls is a function of the uncontrolled emission rate of landfill gas. To exclude
these sources from the MACT floor determination would exclude some of the best-controlled
sources in the industry. The CAA does not suggest that EPA should exclude a control
technology from consideration in the MACT floor because it is so effective that it prevents a
source from being a major source of HAP.
The EPA agrees that according to the definition of part 63 major source, Federally-
enforceable controls must be considered when determining which sources are major sources for
purposes of NESHAP applicability. However, even if a landfill were a major source of HAP
under the landfills NESHAP, it would not necessarily be considered a major source for other
rulemaking purposes. Rule applicability is defined independently for each regulation based on the
thresholds in each regulation. Current and future rulemakings would not be affected by the
designation of major sources under this rule.
The commenters are also correct in recognizing that the landfilb NESHAP applies to area
source as well as major source landfills that meet the EG/NSPS design capacity and NMOC
emission rate criteria, so the distinction of whether a landfill is a major or area source does not
impact the applicability of the landfills NESHAP or the requirements the landfill must meet under
the landfills NESHAP.
Comment: Two commenters (IV-D-07, IV-D-02) stated that EPA changed the definition
of major source (40 CFR 63.2) by using NMOC as a surrogate for HAPs. Two commenters
(IV-D-07, IV-D-02) stated that using NMOC as a surrogate appears arbitrary and intended to
make the NESHAP and EG/NSPS consistent. One commenter (IV-D-02) recommended that
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EPA should reevahiate the need to make the two regulations consistent. Both commenters
(IV-D-07, IV-D-02) stated that the existing definition of major source in 40 CFR 63.2 is clear and
is not related to NMOC. The commenters (IV-D-07, IV-D-02) also stated that EPA has tools
such as the landfill gas model and HAP emission factors to determine which landfills are likely to
emit greater than the major source threshold of 10 tpy of any single HAP or 25 tpy of any
combination of HAP, and should use these tools in its regulatory process. Both commenters
(IV-D-07, IV-D-02) claim no data were presented to support the conclusion that landfills that
exceed the 50 Mg/yr NMOC threshold are also emitting 10 tpy of any HAP or 25 tpy of
combined HAP, but that in the proposed rule EPA considers landfills regulated under the
EG/NSPS to be major sources. One commenter (IV-D-03) also stated that the proposal does not
provide a link between the surrogate NMOC and the section 112 definition of major sources. The
commenter (IV-D-03) stated that the distinction between major and area sources is not clear. The
commenter (IV-D-03) believes that the definition of major source in the proposed landfills
NESHAP conflicts with the definition of major source in section 111 of the CAA and the landfills
NSPS. The commenter (IV-D-03) requested that EPA provide the definition of major source for
the NESHAP.
Response: The commenters misunderstood EPA's intent in using NMOC as a surrogate
for HAP. The EPA has not redefined "major source." The EPA continues to use the section 112
definition of major and area source (40 CFR 63.2) in the final NESHAP. Section 111 of the CAA
and the landfills NSPS do not utilize the term "major source" inconsistently with section 112 of
the CAA and the landfills NESHAP.
The EPA has not claimed that the 50 Mg/yr NMOC emission rate is used to determine
whether a landfill is a major source for HAP emissions. Prior to proposal, EPA did, in fact, use
AP-42 procedures as suggested by the commenter to determine HAP emission rates and whether
landfills are major sources of HAP. The EPA used information in the landfill database on landfill
characteristics such as acceptance rate, time since closure, and time since initial waste placement
in combination with AP-42 default L0, k values and individual HAP concentrations from AP^42 to
determine the maximum uncontrolled HAP emissions. Based on these calculations, EPA
estimated that 1,140 landfills had emissions greater than 10 tpy of an individual HAP or 25 tpy of
the combination of HAP, if the controls were not considered. These 1,140 landfills represent the
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population of landfills that EPA used to determine the MACT floor. This population includes
both major sources and synthetic area sources as described in the previous response. The EPA
also calculated which landfills in the database are subject to EG/NSPS based on their design
capacity and uncontro lied NMOC emission rate estimation procedures in theNSPS. Based on
these calculations, EPA found all MSW landfills with uncontrolled emissions greater than 10 tpy
of an individual HAP or 25 tpy total HAP also have a design capacity equal to or greater than
2.5 million Mg and 2.5 million m3 and have or will have an uncontrolled emission rate greater than
50 Mg/yr NMOC during their lifetime. These landfills will therefore, be required to install
controls by the EG/NSPS. Thus, the MACT floor for major sources is the EG/NSPS level of
control. These analyses are documented in memoranda entered into docket A-98-28 prior to
proposal.
The EPA is also required to regulate area source landfills under section 112(k) of the
CAA as part of the Urban Air Toxics Strategy. The EPA assessed area sources (including
synthetic area sources as well as area sources with uncontrolled emissions less than 10 tpy of any
individual HAP or 25 tpy total HAP) to determine GACT. As described in the proposal
preamble, EPA found that for area sources with design capacities of 2.5 million Mg and
2.5 million m3 or more, and uncontrolled NMOC emission rates of 50 Mg NMOC/yr or more,
GACT is equivalent to MACT. Because the EG/NSPS already requires control of these area
sources, requiring GACT does not impose additional control requirements. The only additional
burden imposed by the NESHAP are reporting requirements that better assure continuous
compliance at a minimal cost. The EPA found that for landfills below these design capacity and
NMOC emission rate criteria, GACT is no control based on consideration of emissions, cost,
economic, and other factors as described in the proposal preamble (65 FR 66677).
The EPA does not expect that every landfill exceeding an uncontrolled emission rate of
50 Mg/yr NMOC is also a major source of HAP. Some landfills exceeding 50 Mg/yr NMOC are
natural area sources whose uncontrolled HAP emissions would be less than 10 tpy individual HAP
or 25 tpy total HAP. Others are synthetic area sources because of their use of the EG/NSPS
collection and control system to control NMOC, actions that also control HAP to below 10 tpy
individual HAP or 25 tpy of total HAP. Having an uncontrolled emission rate greater than 50 Mg
NMOC does not make a landfill a major source of HAP.
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For determining whether a landfill must apply controls and demonstrate control
performance, the rule relies on the surrogate of landfill gas measured as NMOC, rather than HAP.
This use of NMOC as surrogate for HAP minimizes the burden on owners/operators because
NMOC is easier to measure than individual or total HAP. NMOC is an appropriate surrogate for
HAP because all HAP are contained in the NMOC portion of landfill gas. Control of NMOC to
meet theEG/NSPS requirements ensures destruction of organic HAP. Landfill owners/operators
are already required to estimate NMOC under the EG/NSPS and it is not necessary to increase
the burden by requiring specific HAP measurements as well.
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6.0 SSM PLAN AND MONITORING REQUIREMENTS
Comment: Two commenters (IV-D-02, IV-D-07) requested that EPA clarify the
difference between a deviation from the SSM plan and a violation of the standard. Both
commenters (IV-D-02, IV-D-07) suggested that it is difficult to predict how to address a
deviation from a regulatory requirement prior to the deviation actually occurring. The
commenters (IV-D-02, IV-D-07) stated that it is not unusual for an issue to arise that was not
originally considered in the SSM plan. The commenters (IV-D-02, IV-D-07) recommended that
any such issue, if addressed expeditiously according to the NESHAP requirements, should be
considered merely a deviation from the SSM plan, and not a violation of the standard. (See also
comments in Chapter 11 on title V.)
Response: The EPA agrees that it is difficult to predict deviations. However,
owners/operators should read the requirements of the NESHAP and determine to the best of their
ability which malfunctions could prevent them from complying with the regulation. The EPA
believes that most causes of deviations are foreseeable for owners/operators. The owner/operator
must develop and folbw the SSM plan according to the landfills NESHAP and the general
provisions. According to table 1 of subpart AAAA and §§63.6(e) and 63.10(d)(5) of Subpart A,
any time an action taken during a SSM is not consistent with the SSM plan, the source shall
report actions taken within 2 working days after commencing such actions, folbwed by a letter
7 days after the event. If a malfunction event occurs that is not addressed in the SSM plan, the
SSM plan must be revised within 45 days.
Comment: One commenter (IV-D-03) stated that the term "deviation" as used in
§63.1960 is not a deviation, but a violation. The commenter (IV-D-03) also stated that in
§63.1970, the Administrator is given the authority to determine whether failures in implementing
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a SSM plan are violations, but this section does not give the Administrator authority to excuse
failures in SSM plan development.
Response: "Deviation" as used in the landfills NESHAP is described in §§63.1960 and
63.1965 and defined in §63.1990. A deviation can occur when the control device operating
parameter boundaries are exceeded or when the source is out of compliance with other
requirements of the rule. All deviations must be reported. When a deviation occurs, the
enforcement authority will determine whether the source is out of compliance with the NESHAP.
In response to this comment and other comments in Chapter 11, §63.1970 has been
removed from the final NESHAP to eliminate any confusion regarding the use of SSM plans.
Given that the revisions to the general provisions for part 63 (67 FR 16582, April 5, 2002)
included revisions to 40 CFR 63.6(e), a subsection which addresses SSM plans, and given the
other language in the general provisions for parts 60 and 63 relevant to this topic, EPA does not
believe a regulatory section regarding the use of SSM plans is needed in the final NESHAP.
Comment: Two commenters (IV-D-08, IV-D-05) requested that EPA provide a definition
of "malfunction" as it specifically relates to landfill operations. Both commenters (IV-D-08,
IV-D-05) recommended that EPA provide examples and a detailed explanation of where the
definition would apply. The commenters (IV-D-08, IV-D-05) believe that a malfunction is a
situation where equipment is not operating to the extent that a deviation from a standard occurs.
The commenters (IV-D-08, IV-D-05) specifically requested clarification on whether an
exceedance of the 500 parts per million (ppm) surface gas standard would constitute a
malfunction under the SSM plan. The commenters (IV-D-08, IV-D-05) questioned whether an
SSM plan would be needed since the EG/NSPS already details corrective actions for surface gas
concentration.
Response: The EPA believes that the definition of malfunction in 40 CFR part 63 is
adequate and appropriate for landfills: "Malfunction means any sudden, infrequent, and not
reasonably preventable failure of air pollution control equipment, process equipment, or a process
to operate in a normal or usual manner. Failures that are caused in part by poor maintenance or
careless operation are not malfunctions." Routing gas to a control device is a typical requirement
of NESHAP. The EPA expects that owners/operators of landfills can determine malfunctions
(using the part 63 definition) in much the same way as owners/operators of similarly controlled
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sources. The EPA did not include a landfill-specific definition of malfunction in the final
NESHAP.
The EPA does not consider an exceedance of the 500 ppm surface gas standard a
malfunction under the SSM plan. Because the NSPS specifies the method, schedule, and
corrective actbns in case of an exceedance, it would not be necessary to include an exceedance of
the surface gas concentration in the SSM plan.
Comment: One commenter (IV-D-06) congratulated EPA in proposing modest
improvements over the EG/NSPS monitoring requirements. However, the commenter (IV-D-06)
stated that in spite of EPA's position that continuous emission monitoring systems (CEMS) are
not appropriate for MSW landfill sources, CEMS vendors.are confident that systems could be
applied and work reliably on MSW landfill sources.
Response: The commenter did not provide any details about which pollutants or what
type of CEMS could be applied to landfills. The cost of CEMS is higher than the cost of
parameter monitoring, and CEMS have not been sufficiently demonstrated for many HAPs. The
landfills NESHAP requires parameter monitoring instead of CEMS. When monitoring options
other than CEMS are considered, EPA balances more reasonable costs against the feasibility,
quality and accuracy of actual emissions monitoring data. Although monitoring of operating
parameters does not provide a direct measurement of landfill emissions, it is suitable as a
substitute for CEMS. The selected monitoring parameters ensure that the control equipment is
operating properly. This information reasonably assures EPA and the public that the reductions
envisioned by the NESHAP are being achieved.
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7.0 HEALTH EFFECTS
Comment: Two commenters (IV-D-05, IV-D-08) are concerned, that the preamble to the
proposed rule leaves the impression that at the very least, a "mild" health impact will be
experienced from human exposure to landfills. The commenters (IV-D-05, IV-D-08) agree that
the toxic compounds addressed in the preamble could, under appropriate exposures, cause a
health impact. However, the commenters (IV-D-05, IV-D-08) state that a well-operated, modern
sanitary landfill will have no adverse health impact on the public. One commenter (IV-D-08)
cited a California monitoring program. The commenter (IV-D-08) is not aware of any landfill
under the program that has detected toxic compounds in the environment above ambient levels.
The commenters (IV-D-05, IV-D-08) requested that EPA modify the preamble to clarify this
issue.
Response: The EPA recognizes that health risks are significantly reduced at sites that
operate gas collection and control systems meeting the specification in the EG/NSPS. However,
not all landfills collect and control landfill gas. Also, some gas collection and control systems do
not operate effectively. At such sites, health risks would be higher. The EPA considers the
promulgation preamble language to accurately convey the health risks associated with landfills.
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8.0 PETROLEUM CONTAMINATED SOIL
Comment: Three commenters (IV-D-07, IV-D-05, IV-D-02) agreed with EPA that
petroleum contaminated soil (PCS) is not a MS W landfill issue and should not be addressed in the
MSW landfill MACT rulemaking. They agreed the proposal of no control for landfills is
appropriate. Two of the commenters (IV-D-07, IV-D-02) cited emission data from MSW
landfills that showed PCS to be a minor source of HAP. The commenters (IV-D-07, IV-D-02)
specifically mentioned surfece emissions monitoring perforrred under the EG/NSPS and the South
Coast Air Quality Measurement District rule 1150.1, which have not shown significant increases
in total organic emission where PCS were used as landfill cover. The commenters (IV-D-07,
IV-D-02) also reported that surface emissions monitoring of PCS storage piles at landfills have
not shown significant emissions. Afl three commenters (IV-D-07, IV-D-05, IV-D-02) agree with
EPA that PCS disposal at MSW landfills will decline substantially in the future, as the
Underground Tank program becomes less active. One commenter (IV-D-07) stated that because
the highest potential for air emissions from PCS disposal occur during its excavation, handling,
and storage, air emissions from PCS should be evaluated in the context of a future MACT
regulating site remediation activities.
Response: The EPA agrees with the commenters. Based on current emissions and
controls information on PCS used as a cover material at landfills, EPA does not consider this a
landfill issue. It appears that most PCS used at landfills is obtained from excavation and
remediation of underground storage tanks. The number of tanks being excavated is declining and
in many instances, States are allowing PCS to be returned to the excavation site. For these
reasons, PCS used at landfills is declining. Also, evidence indicates that the majority of air
emissions from PCS occur during excavation, storage, and transport prior to entering the landfill.
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The EPA plans to evaluate PCS in the context of a future MACT standard for site remediation
activities.
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9.0 MERCURY
Comment: Four commenters (IV-D-08, IV-D-07, IV-D-05, IV-D-02) reported that they
are not aware of any reliable data showing mercury as a significant emission from MS W landfills.
The commenters (IV-D-08, IV-D-07, IV-D-05, IV-D-02) referred to a detailed test program of
flaring stations at Fresh Kills Landfill, New York, which measured low levels of mercury
emissions. They indicated that other tests have also shown low levels (but did not give specific
references.) Two commenters (IV-D-08, IV-D-05) stated that regulatory authorities have
determined that documented mercury releases from landfills were insignificant. The commenters
(IV-D-08, IV-D-07, IV-D-08, IV-D-02) suggested that ultimately the solution to controlling
mercury releases from landfills is the management of mercury in the waste stream, not regulation
of landfills.
Response: Prior to proposal, EPA considered data from a number of studies, including
one conducted at Fresh Kills Landfill in New York The EPA found insufficient data to
adequately characterize the concentrations of mercury in landfill gas, the emissions of mercury in
fugitive landfill gas and in residuals from landfill gas combustion devices, or to determine their
significance. Because there are no control devices, pollution prevention practices, or other
techniques available to landfills to reduce mercury emissions, and based on available information,
EPA concluded that the MACT floor for mercury control is no emission reduction Because there
are no alternatives above that floor, the MACT standard is also no reduction in emissions.
Currently there is no method for completely destroying mercury, therefore, the best method for
keeping it from entering the environment is to avoid the use of mercury in products that will
eventually enter the MSW stream. However, it should be considered that once mercury has been
created, the next best method of control may be disposal in a modern, lined landfill that combusts
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the generated gas in accordance with the EG/NSPS. In this case, the mercury is converted to a
less hazardous, inorganic form through the combustion process.
Comment: Two commenters (IV-D-07, IV-D-02) support the cooperative efforts of EPA
and the Environmental Research and Education Foundation to test raw landfill gas and emissions
from gas combustion equipment for HAP metals such as mercury and dioxin/furan. One of the
commenters (IV-D-07) recommended that EPA wait until the project is completed before it
makes any decision on mercury controls and therefore, a MACT standard for mercury in landfills
should not be included in the current rulemaking.
Response: The EPA thanks the commenters for their support of the ongoing research
efforts. As stated in the proposal preamble, EPA found the available data insufficient for specific
characterization of the concentrations of mercury in landfill gas, the emissions of mercury in
fugitive landfill gas and in residuals from landfill gas combustion devices. Furthermore, as
described in a later response, EPA has not identified any control alternatives that would reduce
mercury emissions. The EPA is promulgating the rulemaking without a mercury emission limit
rather than delaying the current rulemaking. However, section 112(f) of the CAA requires that
EPA evaluate residual risks and promulgate standards to address residual risks within 8 years of
promulgation of the NESHAP. Also, section 112(d)(6) requires review of theNESHAP every
8 years. If the study results suggest a different approach would be more appropriate, the landfills
NESHAP could be amended at that time.
Comment: One commenter (FV-D-01, IV-G-01) reported that data for mercury air
emissions from three MSW landfills are currently under review by the NJ Mercury Task Force.
These data are included in a drat report from the NJ Mercury Task Force (IV-G-01).
Response: The New Jersey data included an average mercury concentration of
7.5 micrograms per m3 of landfill gas (9.1 x 10"4 ppm) from a series of stack tests performed at the
three landfills including Fresh Kills, New York. The New Jersey report also referred to an
emission factor of 2.9 x 10"4 ppm from a 1997 EPA report. These data were similar to those
reported in a March 5, 1999 memo summarizing available information regarding emissions of
mercury from MSW landfills. This memo gave numbers in the range of 7.0 x 10"7 ppm to 8.8 x
10"4 ppm, which were compiled from nine landfills. Because the NJ emissions information is
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similar, it does not alter EPA's decision to promulgate the NESHAP without a mercury emission
limit.
Comment: One commenter (IV-D-06) noted that while EPA acknowledges that landfills
are a common repository for mercury wastes, and mercury is emitted from MSW landfills, these
emissions are not controlled by EG/NSPS control technologies, and the MACT floor for metal
HAP emissions is no control due to lack of experience in the control of these emissions at
landfills. The commenter (IV-D-06) requested that EPA retain the opportunity to address control
of mercury at landfills. The commenter (IV-D-06) asked that EPA clarify the level of mercury air
emissions from MSW landfill gases. The commenter (IV-D-06) also stated that the MACT floor
is the minimum level of control albwed and that EPA must investigate beyond-the-floor control
options, including the transfer of technologies from other sources.
Response: Low levels of mercury are contained in MSW, in diverse items such as
thermometers, batteries, light switches, thermostats, and flourescent lights. Some mercury in the
waste stream is emitted before the waste arrives at landfills. The mercury volatilizes as mercury-
containing items break during waste collection, compaction, and transport. Mercury is also
emitted from waste deposited on the landfill surface for burial, and is present in landfill gas.
The EPA examined potential mercury control and pollution prevention techniques. The
only control device available to landfills is combustion, however, combustion only changes the
form of the mercury being released to a less toxic form. It does not remove mercury from the
landfill gas. There are no pollution prevention practices for mercury control that landfills could
implement. Once MSW arrives at a landfill, there are no feasible pollution prevention practices
that can reduce mercury emissions from the landfill. It is not possible to separate a mixed waste
stream to remove and recycle small items such as household batteries; thermometers, switches,
and flourescent lights, many of which may have already broken and released mercury during waste
collection and transport before reaching the landfill. Landfills already have random inspections of
waste to help ensure that hazardous waste (which can contain high levels of mercury and is
regulated under RCRA rules) is not illegally placed in MSW landfills. The only real possibility for
pollution prevention that could reduce mercury emissions from MSW landfills is to reduce the
amount of mercury contained in household products that win eventually enter the solid waste
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stream. (In fact, due to economic factors and environmental concerns, the levels of mercury
contained in items such as batteries has declined over the past several years.)
Because there are no control devices, pollution prevention practices, or other techniques
available to landfills to reduce mercury emissions, EPA found that the MACT floor for new and
existing landfills is no reduction in mercury emissions. For the same reasons, EPA has not
identified any beyond-the-floor control options that could be implemented at landfills to reduce
mercury emissions. Therefore, no mercury emissions reductions are required at this time, and the
promulgated rule does not contain emission limitations for mercury. However, section 112(f) of
the CAA requires that EPA evaluate residual risks and promulgate standards to address residual
risks within 8 years of promulgation of the NESHAP. Also, section 112(d) requires review of the
NESHAP every 8 years. If additional information on mercury emissions and control techniques
that would alter this decision becomes available in the future, EPA could amend the rule at that
time.
Comment: Two commenters (IV-D-05, IV-D-08) responded to the citation in the
preamble to the proposed rule of a study that suggested fugitive emission of mercury from the
landfill, as well as mercury emissions from the landfill working lace were measured. Both
commenters (IV-D-05, IV-D-08) agreed with the authors of the study that background soils may
contribute to the emissions measured. The commenters (IV-D-05, IV-D-08) also raised the
possibility in discussion with the authors that measurements at the working face could be
impacted by trace mercury present in the diesel exhaust of landfill mobile equipment. The
commenters (IV-D-05, IV-D-08) stated that due to these confounding factors, it is hard to draw
conclusions from this study, and agreed with EPA's proposal not to regulate mercury emissions.
Response: The EPA'contacted the study authors, who responded that they tested the
diesel exhaust of landfill vehicles and found no mercury, even at distances of 10 to 20 feet, as
compared to tests done on the landfill working face where mercury could be detected at distances
of several hundred feet. One author noted that potential sources of the mercury appeared to
include ocean sediments deposited along with scallop wastes (rather than background soils), and
possibly broken light bulbs. She stressed that the landfill was not a major source of mercury and
that the mercury was not detected once the working face was covered.
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The other author disagreed with the statement made by the commenter that confounding
factors made the study conclusions problematic. He mentioned that he has conducted mercury
testing at three more landfills since the study mentioned, bringing the total number of landfills
tested to six. The emission numbers have been very similar for all six landfills.
The EPA reviewed this mercury emission study prior to proposal, and for reasons stated in
the preamble and in other responses in this chapter, decided not to develop a mercury emission
limit for MSW landfills. The comments do not provide any new information that would change
the decisioa
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10.0 BIOREACTORS
Comment: Three commenters (IV-D-05, IV-D-07, IV-D-02) considered existing
bioreactor information to be insufficient for development of specific regulations. All three
commenters stated that bioreactors are still in the developmental stage and full-scale bioreactor
projects need a few more years to generate data before any changes to existing EG/NSPS
regulations or NESHAP development with respect to bioreactors can be determined. One
commenter (IV-D-05) planned to work with its members and EPA to research the new
technology and help develop regulations, as appropriate. One commenter (IV-D-02) attached a
letter discussing major source landfills after implementation of EG/NSPS for Municipal Solid
Waste Landfills, a paper comparing emissions from bioreactors and conventional subtitle D
landfills, and excerpts from comments to EPA regarding changes in air emissions, greenhouse gas
emissions and methane recovery potential at bioreactor landfills.
Three commenters (IV-D-07, IV-D-02, IV-L-06) recommended that EPA provide interim
technical guidance until more complete bioreactor information becomes available. One
commenter (IV-D-07) suggested that EPA review the data received in response to the April 6,
2000 request for bioreactor information in the Federal Register and base technical guidance to
States and the regulated community on the data. One commenter (IV-D-02) stated that the
technical guidance could include direction to States and owners/operators to encourage
bioreactors to install gas collection systems in the early stages of a project due to the rapid
generation of landfill gas in significant quantities. Another commenter (IV-D-05) also encouraged
developers of bioreactors to install gas collection systems early.
Response: Since these comments were made, EPA has gathered additional information on
the number of bioreactors, their control levels, and the timing of collection and control system
installation. This information was presented in the supplemental proposal for bioreactors (67 FR
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36460, May 23, 2002). The EPA has concluded that the design and operation of bioreactors is
different from conventional landfills, resulting in rapid biodegradation of the waste and
significantly higher emission rates than conventional landfills prior to and shortly after closure.
The appropriate timing of control for bioreactors is, therefore, different from other landfills. In
the MACT floor analysis to support the supplemental proposal, EPA found that 10 of 24
bioreactors have control systems meeting the EG/NSPS requirements and at least 5 of these
installed controls prior to the initiation of liquids addition and sooner then required by the
EG/NSPS. Based on these finding and the rationale expressed in the supplemental proposal and
promulgation preambles, EPA is defining bioreactors and requiring timely control for bioreactors
located at MSW landfills with a design capacity greater than or equal to 2.5 million Mg and
2.5 million m3.
The commenters suggest providing guidance instead of a regulation. These requirements
are being promulgated as a rule under section 112 of the CAA. Under section 112(d), EPA is
required to regulate major sources of HAP, including MSW landfills. The EPA is also authorized
to regulate listed area sources, and landfills were one of the area source categories of HAP
emissions listed under section 112(k) of the CAA on Jury 19, 1999. Section 112 requires
regulation of HAP emissions sources and EPA is not aware of, nor did commenters identify, any
mechanism for guidance directing states or owners/operators to control bioreactor landfills in a
timely manner. The EPA is required to devebp uniform National regulations. Moreover, EPA
does not see any need to not require timely control for bioreactors.
Comment: One commenter (IV-D-10 and IV-L-02) specifically suggested that EPA
should require all bioreactor landfills to install gas collection and controls prior to commencing
bioreactor operations. The commenter (IV-D-10) reported that experience with gas collection
and control systems in California, Delaware and New York indicate that the systems are effective
in controlling odors and landfill gas emissions from conventional and bioreactor landfills. The
commenter (IV-D-10) attached a letter written in response to the April 6, 2000 Federal Register
notice, "Alternative Liner Performance, Leachate Recirculation, and Bioreactor Landfills; Request
for Information and Data" (65 FR 18014) regarding the collective experience of the ASTSWMO
Bioreactor Landfill Work Group with bioreactor landfill operations across the country.
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In a later letter, the commenter (IV-L-02) pointed out that the potential exists for
bioreactor landfills smaller than 2.5 million Mg or 2.5 million m3 to generate significant air
emissions that warrant timely installation of gas collection and control systems. The commenter
(IV-L-02) expressed concern that many States would need to enforce timely installation of gas
collection and controls at these smaller bioreactor landfills, especially those located in moist
climates, in an effort to ensure adequate compliance with State solid waste management
regulations for odor and emissions. The commenter (IV-L-02) recommended requiring control of
bioreactors at landfills with design capacities less than 2.5 million Mg or 2.5 million m3.
Response: The EPA is not requiring control at small area source bioreactor landfills, for
the same reasons that the NESHAP does not regulate small conventional landfills. In determining
GACT for small area sources, EPA fcund that while bioreactors generate larger amounts of
landfill gas early in their life, it is expected that their lifetime total landfill gas generation potential
would not be significantly greater than a conventional landfill accepting the same total amount of
waste. Therefore, potential emissions reductions from control of bioreactors would be similar to
potential long-term emissions reductions from control of small conventional landfills. Requiring
bioreactors at smafl landfills (i.e., landfills with design capacities less than 2.5 million Mg or
2.5 million m3) to install controls would result in additional and unreasonable control costs
because they are not required to install controls by the EG/NSPS. The design capacity exemption
excludes those landfills that can least afford the costs of collection and control systems including
small businesses and particularly, municipalities. Also, controlling smaller landfills would greatly
increase the number of landfills subject to control and result in large control costs relative to the
potential emissions reductions (based on analysis conducted during the development of the
EG/NSPS). Other reasons for exempting small landfills are described in the proposed landfills
NESHAP (65 FR 66677, November 7, 2000) and they also apply to bioreactors. State, local and
tribal agencies may develop more stringent regulations for small bioreactor landfills in cases where
odor and emissions are of focal concern.
Comment: One commenter (IV-D-10) stated that it is inappropriate to increase the
methane generation rate constant, "k", for bioreactors and use it to calculate whether bioreactor
emissions exceed 50 Mg before requiring controls. The commenter (IV-D-10) suggested that it is
possible that use of a bioreactor "k" value to determine NMOC thresholds could be used to delay
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or argue against landfill gas emission controls for individual bioreactor landfill projects. The
commenter (IV-D-10) stated that because of their enhanced rate of landfill gas generation,
bioreactors should be required to collect and control landfill gas emissions prior to the start of
operation. The commenter was also concerned that conventional landfills smaller than 2.5 million
Mg are not required to calculate NMOC emissions or apply controls, but that bioreactors smaller
than 2.5 million Mg could emit more than conventional landfills of this size. Therefore, the
commenter (IV-D-10) does not believe that use of the 2.5 million Mg waste capacity and 50 Mg
per year NMOC thresholds or modifying "k" values are appropriate for application to bioreactor
landfills.
Response: The EPA believes that there is insufficient data to develop a new "k" value for
bioreactors. Although more data will be available in the future, significant new data was not
available in time to be used in this rulemaking. As described in the supplemental proposal, EPA
has chosen an approach to bioreactor control that does not require a k value or an emissions
calculation. Instead, if a landfill exceeds the design capacity criteria and operates a bioreactor (as
defined by liquids addition and the 40 percent moisture criteria) timely control is required.
With regard to the commenter's concern that bioreactors under 2.5 million Mg could emit
more than conventional landfills of the same size, EPA agrees that the emission rate win be higher
in the short term, but the lifelong potential to emit is unlikely to vary significantly between the two
landfill types. In determining GACT for area source landfills, EPA found that it is reasonable that
the EG/NSPS requirements should apply according to the same landfill design capacity thresholds
for conventional and bioreactor landfills. This finding is based on the similarity in the total
amount of emissions and on the cost and other considerations described in the previous response.
As stated in previous responses, EPA is requiring timely control of landfill gas for bioreactors at
landfills with design capacities greater than or equal to 2.5 million Mg and 2.5 million m3.
Comment: One commenter (IV-D-06) noted that EPA estimates that the NESHAP will
affect more than 1,000 of the existing 10,000 landfills, based on typical HAP emissions produced
by conventional landfills. Also, EPA indicates that the rapid generation of landfill gas from
bioreactor operations may not conform to the proposed NESHAP or EG/NSPS requirements.
Based on this information, the commenter (IV-D-06) stated that the thresholds for affected
bioreactors may need to be modified and greater capture and venting to a control device may be
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necessary. The commenter (IV-D-06) also stated that at a minimum, requirements for bioreactor
operations should be included to ensure full compliance and use of control devices.
Response: As stated in previous responses, EPA is requiring timely control of landfill gas
for bioreactors at landfills with design capacities greater than or equal to 2.5 million Mg and
2.5 million m3.
Comment: One commenter (IV-D-10) stated that the suggestion given in the proposal
preamble that final caps be placed on a landfill prior to adding liquids conflicts with the two major
benefits to bioreactor landfill operations. The benefits of gaining additional landfill capacity due
to accelerated waste settlement and the disposal of leachate by recirculation would not be possible
with a final cap in place. The commenter (IV-D-10) also stated that if settlement occurred
quickly after liquid addition, it would be preferable for the settlement to occur before the final
cover system was installed.
Response: The EPA has not included this requirement in the final landfills NESHAP. The
EPA would like to point out that bioreactors at Yolo County landfill in California, as well as
multiple New Jersey sites, don't begin recirculating leachate until a final cap has been placed.
These sites recirculate below the surface. Sites utilizing final caps prior to recirculation have the
most environmentally protective bioreactor operations achievable. The EPA does not require
placement of final caps before recirculation, but does recommend the practice for sites wishing to
attain high levels of environmental protection while utilizing bioreactor technology. However, as
long as gas is being efficiently collected and controlled from the areas where leachate recirculation
is occurring, according to the collection and control system requirements in the EG/NSPS, the
landfill will be in compliance with the rule.
Comment: One commenter (IV-D-10) addressed the negative tone with respect to
bioreactor landfill operations of EPA's rulemaking preamble. The commenter (IV-D-10) believes
that the preamble text concerning the health impacts, the threat of landfill fires and pollution
potential of bioreactor landfills can be perceived as being overly negative. The commenter
(IV-D-10) stated that, when operated under proper direction, bioreactor landfills pose no more
harm to public health and the environment than a conventional landfill. The commenter also
noted that the potential for landfill fires exists with the current regulations for conventional
landfills and is not an issue for bioreactors alone. The commenter (IV-D-10) suggested that the
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preamble be modified to include the positive attributes which bioreactor landfilb may offer
compared to conventional landfills, using the following information:
• increased efficiency in collection and control of landfill fugitive gases, resulting in
reduced air emissions;
• reduction in greenhouse gas emissbns;
• potential market for beneficial use of wastewater and sludge;
potential landfill mining and beneficial use of stabilized residual wastes; and
• improved economy and revenue as a result of more efficient utilization of biogas
energy than in conventional landfills.
Response: The EPA did not intend the preamble to address bioreactors in a negative
manner. The EPA recognizes that a bioreactors may offer benefits such as reduced landfill space
and that if bioreactors are controlled from near the start of their operation this will result in a
decrease in air emissions.
Comment: Five commenters (IV-L-01,1V-L-02,1V-L-03,1V-L-05, IV-L-07) generally
supported EPA's approach for the application of NESHAP to landfills operating as bioreactors
and the requirement of timely collection and control of emissions from bioreactor landfills. One
commenter (IV-L-02) stated that the bioreactor requirements could help to motivate future
proposed amendments to current RCRA regulations (40 CFR part 258) which would allow liquids
addition other than leachate to bioreactor landfills, thus advancing this innovative landfill
operational technology nationwide. One commenter (IV-L-07) expects bioreactor landfills to
improve the efficiency of landfill gas emission control and promote greater use of landfill gas fcr
energy recovery.
One commenter (FV-L-06) who opposed the proposed rulemaking believes that existing
information of emissions from bioreactor landfills is insufficient for the development of MACT
standards. The commenter (IV-L-06) contended that bioreactor landfills are currently in the
developmental stage. The commenter (IV-L-06) suggested that EPA defer any regulatory
decisions on the air emissions from bioreactor landfills until new data or a better understanding of
bioreactor landfill emissions become available. Another commenter (IV-L-04) who opposed the
proposed rule recommended, in lieu of the rule, giving States latitude as to when to require early
installation of gas collection and control systems for all bioreactors, regardless of size or waste
mass moisture content. Due to the fact that information and data on bioreactor landfill air
emissions are only beginning to be collected, the commenter (IV-L-04) suggested that EPA
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provide guidelines for bioreactor landfills that could be used by States to make site-specific
judgements.
Response: Bioreactors result in more rapid bio degradation of waste and higher emissions
than conventional landfills shortly after waste placement. Recent literature suggests that a
bioreactor cell can very quickly (within about 90 to 180 days of operation) reach the same gas
generation rate as a conventional landfill cell does in 2 years of operation. Through available
data, EPA was able to identify 24 anaerobic bioreactors, 10 of which have gas collection and
control systems meeting the control levels of the EG/NSPS. At least five of these controlled
bioreactors had control systems installed or will have them installed prior to initiating liquids
addition to the bioreactors and sooner than required by the EG/NSPS. Based on this information,
EPA contends that a substantial amount of data are available to support regulations requiring
timely collection and control of emissions from bioreactor landfills. Any delay in the
promulgation of this rule will result in the undue release of additional HAP from bioreactor
landfills. As explained in the response to the first comment in this chapter, EPA is required by
section 112 of the CAA to develop uniform National standards. The EPA is not aware of, nor did
the commenter identify, any mechanisms for guidance directing States or owners/operators to
control bioreactors in a timely manner.
Comment: Three commenters (IV-L-03, IV-L-06, IV-L-07) expressed concern that due
to a wide range of possible development scenarios, commencing operation of the gas collection
and control system within 90 days of liquids addition may not be appropriate in all cases. Two
commenters (IV-L-06, IV-L-07) stated that the generation rates of landfill gas during the initial
development phases of bioreactors are a function of many factors and substantial quantities of
recoverable landfill gas may not be available due to low waste acceptance rates, hybrid bioreactor
operations, high inorganic waste fractions, or low liquid addition rates where gas generation is
likefy to be similar to that of conventional landfills. Under these circumstances, premature startup
of the gas control system may result in significant volumes of air being introduced into the
bioreactor, thus kilfing methane-producing bacteria. Both commenters (IV-L-06, IV-L-07)
acknowledged that these factors would not be as much of a concern if it was clarified in the rule
that operation of the collection and control system must begin 90 days after 40 percent moisture
content is reached. All three commenters (IV-L-03, IV-L-06, IV-L-07) recommended extending
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the startup time frame to 180 days or establishing a process for waiving or delaying the startup
date if local conditions warrant.
Response: In response to this comment, EPA has changed the final NESHAP to allow
180 days instead of 90 days to begin operation of the collection and control system. The EPA is
aware that bioreactors may experience variable emission rates upon startup due to site-specific
factors such as those described by the commenters. Furthermore, gas collection systems for
bioreactors are site-specific and are likely to use newer designs, so operators may require time to
gain experience and make operational adjustments to their systems. The 180 day period will
allow time to landfill operators to adjust their collection systems such that they can achieve
continuous, stable collection and control system operation.
Comment: Four commenters (IV-L-03, IV-L-04, IV-L-06, IV-L-07) requested
clarification as to whether the rule was meant to require the operation of the gas collection and
control system within 90 days after the initial liquid addition or within 90 days after the moisture
content has reached 40 percent. The cormrenters (IV-L-03, IV-L-04, IV-L-06, IV-L-07) stated
that they believed EPA's intent was to require operation of the gas collection and control system
after the moisture content reached 40 percent. The commenters (IV-L-03, IV-L-04, IV-L-06,
IV-L-07) noted that it may take longer than 90 days of liquids addition to reach a moisture
content of 40 percent.
Response: The commenters are correct, it was EPA's intent that attaining 40 percent
moisture triggers the operation of the control system, and not merely the introduction of liquids.
If operation of the control system is based on the time of liquids addition and the landfill has not
reached 40 percent moisture content within 90 days, then the rule (as proposed) would be
requiring collection and control to be installed and operated prior to the landfill meeting the
definition of a bioreactor. The EPA has revised the rule to clarify that the operation of the
collection and control system is required within 180 days after the landfill starts liquids addition or
within 180 days after the date the bioreactor has first reached 40 percent moisture content (ie.,
180 days after the landfill has met the definition of bioreactor), whichever is later. Landfills must
use the procedures in §63.1980(g) and (h) to determine when 40 percent moisture content is
reached. (No calculation is needed if the landfill begins operating the collection and control
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system within 180 days after the initial liquids addition.) Installation of the collection and control
system is still required prior to liquids addition, as required in the supplemental proposal.
Comment: Two commenters (IV-L-02, IV-L-06) believe that prescribing a target waste
mass moisture content of 40 percent in the definition of bioreactor is not supported by scientific
data. One of the commenters (IV-L-02) stated that the only significance of the 40 percent
moisture content referenced in the supplemental proposal is that it represents the lower bounds of
the moisture content range of 40 to 70 percent recommended in literature for achieving optimum
waste mass decomposition. The commenter (IV-L-02) suggested that EPA remove the
40 percent moisture content threshold from the bioreactor definition for two reasons. First, they
claimed that its removal would minimize sampling requirements for the waste mass moisture
content. Second, removing the 40 percent moisture criteria would allow latitude for States to
require early installation of controls without needing to have attained the 40 percent moisture
threshold where there are bcal emissions and odor concerns. Although the commenter (IV-L-02)
does not want the 40 percent moisture content to be included in the bioreactor definition, the
commenter (IV-L-02) understands the importance of a bioreactor landfill needing to attain an
optimum moisture content for enhanced waste mass decomposition. The commenter (IV-L-02)
suggested discussing the optimum moisture content range (40 to 70 percent) as guidance in the
preamble. One commenter (IV-L-06) pointed out that few MSW landfills have collected data
correlating the amount of liquids added and recirculated with the rate, quantity, and quality of
landfill gas emissions. The commenter (IV-L-06) expressed concern that selecting a trigger level
of 40 percent moisture content is arbitrary and not supported by research data. The commenter
(IV-L-06) stated that without scientifically valid data, an appropriate moisture content threshold
cannot be selected or defended based on the amount of gas that may be generated and potentially
captured.
One commenter (IV-L-07) supports the 40 percent moisture content proposed because the
developing science on bioreactors supports this threshold. The commenter (IV-L-07) explained
that one study sited 50 to 70 percent moisture content as ideal for bioreactors. The commenter
(IV-L-07) contended that a lower number than the optimal, but one that represents a moisture
content likely to accelerate gas production, is an appropriate threshold for EPA to choose. The
commenter (IV-L-07) stated that in order to justify accelerated collection and control systems at
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bioreactor landfills, EPA must establish that moisture conditions wifl be substantially in excess of
those found in conventional landfills. The commenter (IV-L-07) believes a 40 percent moisture
content cutoff for bioreactors provides the necessary distinction between substantially higher
moisture conditions in bioreactor landfills and moisture contents of 10 to 35 percent found in
conventional landfills. The commenter (IV-L-07) added that a 40 percent moisture content
threshold would require bioreactor landfills in non-arid climates to be controlled as bioreactors
while allowing landfills in arid climates that add liquids but do not reach 40 percent moisture and
have emissions comparable to conventional landfills, to use existing NESHAP and EG/NSPS
requirements as an adequate level of control.
Response: It is necessary to establish a clear definition of bioreactor to determine when
the early installation and operation of a collection and control system applies. Including a percent
moisture content in the definition provides a measurable parameter that can be used to determine
applicability. Section 112 requires EPA to set uniform National standards. Definitions,
applicability criteria, and control requirements must be clearly stated and cannot be left to State
discretion. Section 112 does not provide a mechanism for issuing guidance instead of a uniform
National standard. The EPA based the selection of 40 percent moisture content on the best
available data on bioreactors. The EPA agrees with commenter IV-L-07 that the available
scientific information supports this threshold. The literature suggests that moisture content of the
waste should remain in the range of 40 to 70 percent to optimize bioreactor operations. It seems
clear that once the moisture content is at least 40 percent, landfill gas will be generated at levels
significantly greater than a conventional landfifl. Under State or local regulatory authority, a
State, local or tribal agency may require early control for areas with less than 40 percent moisture
if it is necessary to address focal concerns.
The 40 percent moisture criteria will not require burdensome sampling. The EPA expects
that most landfills that add liquids other than leachate will meet the definition of a bioreactor. If
the landfill owner/operator complies with the bioreactor control requirements, they are not
required to measure or calculate waste moisture content. Only those landfills that add liquids but
do not install control systems or do not begin operating their controls within 180 days after liquids
addition must determine their moisture content to show that it is less than 40 percent. The
regulation allows landfills to use site-specific procedures to determine moisture content rather
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than presenting one specific method. It clarifies that mass balance calculations can be used.
Landfills are not required to perform extensive in-situ waste mass moisture measurements.
Comment: The EPA received five comments pertaining to the exclusion of landfills that
recirculate leachate and do not add any other liquids from the definition of a bioreactor landfill.
Three commenters (IV-L-02, IV-L-03, IV-L-07) who supported the exclusion stated that liquids
addition other than that provided by leachate recirculation is normally needed to achieve optimum
moisture for bioreactors. One of these commenters (IV-L-07) stated that including liquids other
than leachate in the bioreactor definition distinguishes between conventional landfills that
recirculate leachate for the primary purpose of leachate management and bioreactor landfills that
introduce liquids to achieve optimal levels of biodegradation and gas generation.
One commenter (IV-L-04) who opposed the exclusion and one of the commenters
(IV-L-02) who supported the exclusion contended that a landfill in a relatively moist climate
could sustain an effective bbreactor operation by leachate recirculation abne. Both commenters
(IV-L-02, IV-L-04) also expressed concern that landfills recirculating leachate only may reach the
40 percent moisture level in the waste by recirculating leachate from the entire landfill into a
single bioreactor cell. One of these commenters (IV-L-04) pointed out that there were odor
problems (due to enhanced gas production) at landfills in his State that began recirculating
leachate without a collection and control system. The commenter (IV-L-04) stated that his State
now requires collection and control for all landfills that recirculate leachate.
Another commenter (IV-L-06) who opposed the exclusion contended that minimal
scientifically valid data has been collected to allow for the exclusion. The commenter (IV-L-06)
explained that data to support the exclusion are not available because most leachate is recirculated
as a leachate treatment method and not to create bioreactor conditions, a secondary benefit.
Response: The EPA has not changed the bioreactor definition. The commenter who
opposed the exclusion provided no data to support their position. The EPA believes that a very
small percentage of bioreactors in moist climates would reach a moisture content of 40 percent
with leachate recirculation only. Due to variations in rainfall throughout the year, it would be
difficult to consistently maintain a high moisture content in the waste to function as a fully
operational bioreactor. Landfill owners that decide to create bioreactors in the future will
typically plan to operate a large area as a bioreactor to achieve potential benefits such as earlier
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stabilization of waste, extended use of current sites, and reduced need for new sites. Liquids
addition would be needed to maintain suchbioreactors.
It would be a large and unnecessary burden to require potentially hundreds of landfills that
recirculate leachate but do not add any other liquids to calculate their percent moisture content
and determine if they are abioreactor when EPA expects in most if not all cases that they win not
meet the 40 percent moisture criteria in the definition of a bioreactor. These landfills would still
be subject to the NESHAP and EG/NSPS control requirements for conventional landfills, which
will require gas collection and control after their NMOC emissions reach 50 Mg/yr. State, local,
or tribal agencies may develop more stringent regulations for landfills recirculating leachate in
cases where odor or air emissions warrant active landfill gas collection and control.
Comment: One commenter (IV-D-10) stated that all bioreactors, including aerobic
bioreactors should be controlled prior to commencing operation. Four commenters (IV-L-02,
IV-L-04, IV-L-06, IV-L-07) encouraged EPA to include aerobic bioreactor operations by
imposing the anaerobic bioreactor emission requirements on aerobic bioreactor landfills. Two of
these commenters (IV-L-06, IV-L-07) provided references to available literature on volatile
organic compound (VOC) emission tests from lab and full-scale MSW compost operations.
These commenters contend that the studies suggest that emissions of VOC or HAP are likely to
occur from an aerobic bioreactor landfill. One commenter (IV-L-07) believes these studies show
that introduction of air into MSW landfills or composts and the increased temperatures at which
they operate can act as a carrier for HAP and NMOC. The commenters (IV-L-02, IV-L-04,
IV-L-06, IV-L-07) acknowledged there is a limited amount of data on air emissions from aerobic
bioreactors, but believe available literature suggests that equivalent controls for aerobic bioreactor
landfills may be warranted; although, one of these commenters (IV-L-06) concluded that there is
not enough scientifically valid data available at this time to develop a MACT standard for aerobic
bioreactor landfills. Five commenters (IV-L-08, IV-L-09, IV-L-10, IV-L-11, IV-L-12) agreed
there is limited data, especially HAP emissions data, and believe it is important to exclude aerobic
bioreactors at this time.
Response: The EPA does not consider the references provided for composting operations
to be applicable because composting of MSW is not the same as operating an aerobic bioreactor
within a MSW landfill. The EPA knows of no full scale aerobic bioreactors in operation in the
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United States, and an insufficient amount of aerobic landfill data are available to properly
characterize HAP emissions from aerobic bioreactors. The EPA does not expect a significant
number of aerobic bioreactors to be built in the next several years (in contrast to the trend for
anaerobic bioreactors). For these reasons, EPA has determined that it is not appropriate to
include aerobic bioreactors in the definition of bioreactor or the requirements for timely control of
bioreactors. However, portions of a landfill that are operated as aerobic bioreactors would
continue to be subject to the EG/NSPS and the NESHAP requirements for conventional landfills.
Under section 112(f) of the CAA, EPA will evaluate residual risks and promulgate standards to
address residual risks within 8 years of promulgation of the NESHAP. In addition,
section 112(d)(6) requires review of the NESHAP every 8 years. At that time, EPA will consider
any new information on the prevalence and emissions of aerobic bioreactors and controls to
determine if any additional requirements are necessary.
Comment: Seven commenters (IV-L-02, IV-L-04, IV-L-08, IV-L-09, IV-L-10, IV-L-11,
IV-L-12) noticed that although the preamble to the supplemental proposal specifically excludes
aerobic bioreactor operations from the proposed regulations, the bioreactor definition in the rule
makes no distinction between aerobic and anaerobic bioreactors. Thus, the proposed definition of
bioreactor as it currently reads would falsely include aerobic bioreactor operations.
Response: The EPA fully intended to exclude aerobic bioreactor operations from the
bioreactor definition and the requirements for timely control of bioreactors, as clearly stated in the
supplemental proposal preamble. The EPA has revised the definition of bioreactor to clarify that
bioreactors, as defined for purposes of this rule, are used to accelerate or enhance the anaerobic
(without oxygen) biodegradation of the waste.
Comment: One commenter (IV-L-06) believes that the ten bioreactor landfills used to
determine the MACT floor for bioreactors do not represent full-scale operational bioreactor
landfills. This commenter (IV-L-06) believes the majority of bioreactor landfills in operation are
considered experimental or research projects. The commenter (IV-L-06) contended that the gas
collection systems at these experimental bioreactors were designed either after waste was already
placed (retrofitted in closed landfill cells) or to evaluate gas collection and liquid injection system
design. The commenter (IV-L-06) suggested that EPA review its data for these ten operational
bioreactor landfills to determine whether they are full-scale or experimental bioreactors.
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Response: In determining the MACT floor for bioreactors, EPA identified 24 operational,
anaerobic bioreactors in the U.S., based on available data. For categories or subcategories with
fewer than 30 sources, the CAA requires that the MACT floor for existing sources be based on
the best-performing 5 sources. In reviewing the information used to identify the ten bbreactor
landfills that have collection and control systems and set the bioreactor MACT floor, EPA found
that at least eight are known to have full-scale operational bioreactors. These eight bioreactor
landfills are used for long-term bioreactor operations, not pilot research projects. Because more
than five sources in the subcategory have timely control, the MACT floor remains unchanged
even if only full-scale operational bioreactors are considered. For reasons stated in the preamble
and other responses in this section, the bioreactor provisions of the NESHAP apply to bioreactors
at landfills with design capacities greater than or equal to 2.5 million Mg and 2.5 million m3,
whether the entire landfill or a portion of the landfill (i.e., a cell or group of cells) is operated as a
bioreactor. hi other words, pilot-scale bioreactors within large landfills must fulfill the same
requirements as full-scale bioreactors.
Comment: Two commenters (IV-L-03, IV-L-07) requested clarification that landfill gas
condensate is considered part of leachate, as used in the bioreactor definition of the rule. The
commenters (IV-L-03, IV-L-07) explained that landfill gas condensate is often nixed with
leachate for recirculation or disposal. One commenter (IV-L-03) stated that inclusion of
condensate with "leachate" would also eliminate the potential for a small area of waste
surrounding a condensate drip leg to inadvertently achieve a moisture content greater than
40 percent.
Response: The EPA does consider landfill gas condensate to be included in the term
"leachate." Condensate is generated when landfill gas is recovered through the collection system.
Landfill gas condensate is small in volume compared to leachate, and is typically collected and
treated along with leachate. The definition of bioreactor has been revised to reflect this
clarification.
Comment: One commenter (IV-L-05) requested that EPA address the issue of leachate
collection system performance to assure that bioreactor landfills are a viable alternative to
conventional landfill designs. The commenter (IV-L-05) believes that typical leachate collection
systems designed for conventional MSW landfills would be susceptible to severe clogging when
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operating under "bioreactor" conditions. The commenter (IV-L-05) is concerned that any
significant increase in leachate flux through the leachate collection system, due to bioreactor
conditions, would accelerate the production of chemical precipitates and biological growths
within the collection system components, thus adversely affecting then- performance. The
commenter proposed that EPA make several changes to the NESHAP, 40 CFR part 258 (RCRA
regulations), and EPA's technical guidance to reduce clogging of leachate collection systems at
bioreactor landfills.
Response: EPA does not have the authority to regulate the design of leachate collection
systems under NESHAP, which are developed under section 112 of the CAA and focus on
control of HAP emissions. The RCRA rulemaking and landfill design guidance are outside the
scope of this rulemaking. The issue of potential clogging of leachate collection systems at
bioreactor landfills should be addressed by the owner/operator of the bioreactor during system
design and operation.
Comment: Two commenters (IV-L-03, IV-L-07) supported EPA's approach for using
site-specific procedures to determine moisture content of the waste mass within bioreactor
landfills. One commenter (IV-L-03) believed that mass balance calculations will usually be
necessary because accurate methods for in-situ waste moisture measurement do not currently
exist. Another commenter (IV-L-07) added that EPA should avoid the implication that moisture
content should be regularly monitored for conventional landfills, or that once a bioreactor landfill
has begun operating, that moisture content must be included in a monitoring plan for the facility.
Response: The EPA is encouraged by the commenters' acceptance of site-specific
approaches for determining the moisture content of the waste mass in bioreactors. EPA believes
that allowing site-specific procedures minimizes the recordkeeping burden by allowing landfills to
use calculations they already have available. EPA agrees that most landfills will use a mass
balance approach. It is important, however, that these procedures and assumptions are
appropriate and well-documented, as required by §63.1980(g) and (h). To be considered a
bioreactor, a liquid other than leachate must be added (leachate includes landfill gas condensate),
and the waste must have a minimum average moisture content of 40 percent by weight.
Therefore, calculating moisture content at conventional landfills is not necessary unless liquids
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other than leachate are added to the waste mass. Moisture calculation is required in only two
situations:
(1) Landfills that add liquids other than leachate but do not comply with the bioreactor
control requirements must calculate moisture content to demonstrate that it is less
than 40 percent.
(2) Landfill bioreactors that do not start operating the gas collection and control
system within 180 days after initiating liquids additbn, but instead elect to start
operating the gas collection and control system within 180 days after the waste
moisture content reaches 40 percent must calculate waste moisture content to
determine when 40 percent is reached. They must report within 90 days of
achieving 40 percent moisture content.
Landfills that do not add liquids other than leachate, and landfills that add liquids and
comply with the bioreactor control requirements within 180 days of initiating liquids addition do
not have to calculate waste moisture content at all. A bioreactor landfill is not required to include
moisture content as part of its monitoring plan.
Comment: Two commenters (IV-L-02, IV-L-04) requested that EPA establish which
liquids would be acceptable for addition or recirculation into a landfill for purposes of bioreactor
operations. One of these commenters (IV-L-04) suggested that EPA explain or define the term
"liquid" to include only aqueous liquids which have been demonstrated to be compatible with the
microbial decomposition process in the landfill, such as water, storm water runoff, certain waste
waters, and other liquid wastes. Both commenters (IV-L-02, IV-L-04) explained that not all
liquid wastes are appropriate for bioreactor operations and can actually be detrimental to the
biodegradation process. One commenter (IV-L-02) stated that waste water sludges or other solid
wastes currently accepted at several MSW landfills may contribute significantly to the moisture
content such that leachate quantities abne may be sufficient to sustain an effective bioreactor.
Response: It is not EPA's responsibility to determine what type of liquids are appropriate
for bioreactor operation. This is best handled on a site-specific basis by engineers designing and
operating the bioreactor. The EPA considers the term "liquid" to refer to a fluid that has no
independent shape but has a definite volume, as defined by Webster's dictionary. The EPA
believes that the term "liquid" is commonly used and understood, and does not believe a definition
unique to the landfill rule is necessary. The EPA regards waste water sludges as liquids other
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than leachate that would be added into the waste mass and contribute to the bioreactor operation.
The preamble to the rule has been revised to include this clarification.
Comment: One commenter (IV-L-06) expressed concern that the requirement of a gas
collection and control system for bioreactors that meets the EG/NSPS requirements for large
MSW landfills may be operationally impractical The commenter (IV-L-06) explained that
vertical collection wells spaced at the distances required by the EG/NSPS would be in the way of
further waste placement, as well as landfill vehicles. This means that liquids addition could not
begin within a landfill cell until after closure of that cell; however, the waste should be wetted as
placed to maximize biodegradation rates.
Response: The EPA responds that designs are available that allow installation of a
collection system prior to liquids addition. Bioreactor landfills use a variety of vertical and
horizontal collection systems, and several have installed collection systems prior to liquids
addition. For example, horizontal gas collection systems have been installed in the same area as
the leachate recirculation system as the bioreactor is being filled with waste. As waste is placed in
the area and leachate recirculation is begun, the gas collection system will already be in place and
can begin operation as well. The EG/NSPS (§60.752(b)(2)) include general criteria for collection
system design but allow for a variety of site-specific vertical or horizontal collection system
designs. Timely control of each area within the bioreactor is necessary to control the higher HAP
emission rates in the first two to five years of bioreactor operation.
Comment: One commenter (IV-L-07) agrees with EPA's allowance for early shutdown of
o
gas controls after closure of a bioreactor landfill. The commenter (IV-L-07) requested that EPA
clarify that the bioreactor portion of an integrated collection and control system, where gas is
gathered from both conventional and bioreactor landfill cells, is albwed to shutdown early, similar
to stand-alone controls for a bioreactor landfill. The commenter (IV-L-07) understands that any
residual emissions from the bioreactor landfill cells would still need to be accounted for under the
EG/NSPS and NESHAP requirements for conventional landfills. The commenter (IV-L-07) also
requested extending early shutdown of gas control systems to bioreactor landfills where it can be
demonstrated that gas depletion is equivalent to a bioreactor landfill. The commenter (IV-L-07)
suggested applying this condition to landfills that never meet 40 percent moisture content, but
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have accelerated degradation through liquids addition or leachate recirculation and exhausted the
gas supply of the landfill soon after cbsure.
Response: The EPA's intent is to albw shutdown or removal of the collection and control
system for the bioreactor when the criteria in §63.1952 for bbreactor control system removal are
met. The commenter is correct that if an integrated gas collection and control system collects gas
from both conventional and bioreactor landfill cells, the bioreactor portion of the collection
system can be shut down when the bioreactor meets the criteria in §63.1952(a) or (b). The
landfill would continue to collect and control gas from the conventional portion of the landfill
until the EG/NSPS criteria for control system removal are met.
With regard to the commenters second question, the provisions for timely removal of
bioreactor collection and control systems apply only to landfill areas that meet the definition of a
bioreactor and have installed controls in a timely manner, as required by the bioreactor provisions.
Extending early control system removal to other areas of the landfill that are not bioreactors and
did not install controls early would result in greater emissions. Research indicates that a waste
moisture content in the range of 40 to 70 percent is needed for optimum bioreactor operation, and
at lower moisture levels, waste will degrade less rapidly and emissions win last for a longer period
of time. The EG/NSPS already contains sufficient and appropriate provisions allowing for control
system removal from landfill areas that are not bioreactors. In particular, if an area within the
landfill is nonproductive according to the criteria in §60.759(a)(3)(ii) of 40 CFR 60 subpart
WWW (the NSPS), then the landfill owner/operator does not need to collect gas from that area.
These provisions would albw an owner/operator to exclude areas where gas production has
declined as long as the total areas excluded contribute less than 1% of the NMOC emissions from
the landfill. Under the EG/NSPS, the collection and control system can also be capped or
removed when the landfill is closed, the control system has been operating at least 15 years, and
NMOC emissbns from the landfill are less than 50 Mg/yr as specified in §60.752(b)(2)(v) of
subpart WWW.
Comment: Two commenters (IV-L-02, FV-L-04) expressed concern that current
regulations which govern MSW landfills nationwide (40 CFR part 258) strictly prohibit the
addition of liquids other than leachate (including condensate) into MSW landfifls. These
commenters (IV-L-02, FV-L-04) questioned EPA's action to regulate bioreactor landfills in a
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manner that is not currently allowed under related regulations governing landfills. One of the
commenters (IV-L-04) pointed out that the proposed definition of a bioreactor landfill would
exclude all bioreactor projects in his State, because under the current provisions of 40 CFR
part 258 only leachate can be recirculated into a landfill. The other commenter (IV-L-02)
suggested that EPA revise the proposed rule to address the feet that to allow liquids addition
other than leachate either an XL project authorization or other regulatory revision is necessary.
The commenter (IV-L-02) noted that a proposed regulation for research, development, and
demonstration (RD&D) permit provisions for 40 CFR part 258 (67 FR 39662, June 10, 2002)
would allow approved States the ability to issue RD&D permits to allow liquids other than
leachate to be added into landfills. The commenter (IV-L-02) stated that it would be presumptive
for EPA to use information from the proposed RD&D permits rule when they are not yet
promulgated.
Response: The EPA recognizes that it is difficult for an owner/operator of a municipal
landfill to operate a large bioreactor in the U.S. as defined in today's rule. This is because of the
Federal criteria regulating MSW landfills, specifically 40 CFR part 258.28 which prohibits the
addition of liquids other than leachate and gas condensate to a landfill and 40 CFR part 258.26
which limits the entry of rainwater into municipal landfills through specified run-on control
systems. However, EPA responds that there are bioreactors in existence in the U.S. that are
currently adding liquids other than leachate, either through Project XL or other case-by-case
approvals from States. The EPA has the authority and obligation to regulate HAP emissions from
bioreactor landfills, regardless of how these bioreactor landfills are allowed to add liquids other
than leachate. In addition, on June 10, 2002, EPA proposed a revision to 40 CFR part 258 that
would allow the Director of an approved State to issue a RD&D permit for a MSW landfill (67
FR 39662). This proposed RD&D rule would allow the States to grant variances to certain parts
of the MSW landfills criteria (40 CFR part 258) through the issuance of RD&D permits. As a
result, once this RD&D rule becomes final and an approved State integrates the new Federal
regulations, the Director of an approved State may issue permits which could potentially allow for
the operation of a bioreactor landfill as long as there is no increased risk to human health and the
environment (as compared to a municipal landfill permitted under the existing 40 CFR part 258
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criteria). Therefore, once the proposed rule allowing RD&D permits for municipal landfills
becomes final, EPA expects the number of bioreactor landfills to increase over the next few years.
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11.0 TITLE V
Comment: Two commenters (IV-D-02, IV-D-07) recommended that EPA clarify that
deviations that are properly addressed in accordance with the SSM plan under the proposed rule
will not become violations under any CAA program or permit, such as a title V permit, in which
the standard, limitation, prohibition, or other Federally-enforceable requirement is contained. The
commenters (IV-D-02, IV-D-07) stated that the proposed rule suggested that any deviations that
occur during SSM would not be violations under section 112 if the SSM plan were adequate and
followed. However, the commenters (IV-D-02, IV-D-07) are concerned that such a deviation
might be considered a violation under title V and/or the EG/NSPS for MSW landfills.
Response: The EPA responds that to the extent that a source is in compliance with the
applicable SSM provisions of parts 60 and 63, the source is in compliance with its title V permit
with respect to these specific applicable requirements. In terms of the EG/NSPS for landfills,
deviations, and therefore potential violations, will be defined by the applicable requirements (i.e.,
40 CFR part 60, subpart WWW, an EPA-approved and effective State or tribal plan, or the
Federal plan that implements the EG.
Furthermore, in response to this comment, §63.1970 has been removed from the final
NESHAP to eliminate any confusion regarding the use of SSM plans. Given that the revisions to
the general provisions for part 63 (67 FR 16582, April 5, 2002) included revisions to §63.6(e), a
subsection which addresses SSM plans, and given the other language in the general provisions for
parts 60 and 63, the NSPS for landfills, and the landfills Federal plan relevant to this topic, EPA
does not believe a regulatory section regarding the use of SSM plans is needed in the final
NESHAP. See 40 CFR 60.1 l(c), 60.755(e), 63.6(e), 63.6(f)(l), and 62.14354(b).
Comment: Two commenters (IV-D-05, IV-D-08) requested a more detailed discussion of
which reporting requirements under the NESHAP would satisfy specific requirements under the
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title V program. Both commenters (IV-D-05, IV-D-08) cited a specific example: The proposed
rule requires that the landfill owner/operator notify EPA within 2 days of a SSM event. The
commenters (IV-D-05, IV-D-08) questioned whether this requirement would satisfy the "prompt
reporting" requirements of the title V program. The commenters (IV-D-05, IV-D-08) stated that
if the requirement were meant to fulfill the "prompt reporting" requirements of title V, then it
would be appropriate to allow delegation of the reporting requirements to the State or local
enforcement agencies, in accordance with their title V programs. The commenters (IV-D-05,
IV-D-08) understood that, in accordance with 40 CFR part 70 regulations, the State or local
enforcement authorities should provide their own definition of "prompt reporting".
Response: The EPA responds that, as many owners/operators of landfills subject to this
subpart wifl have the requirements of the landfills NESHAP in their title V permits, any reports
submitted for such sources will need to satisfy the reporting requirements of the landfills
NESHAP and title V (e.g., type of report, content of report, and frequency of submission). A
permitting authority is not, however, precluded from consolidating required reports as long as all
reporting requirements of the NESHAP and title V are met.
The EPA would like to emphasize that under 40 CFR part 70 or 71, any application form,
report, compliance certification, or other document required by a permit to be submitted to a
permitting authority must contain certification by a responsible official that the statements and
information in the document are true, accurate, and complete. See 40 CFR 70.5(d), 70.6(cXl),
71.5(d), and 71.6(c)(l). Thus, to the extent reports submitted under the NESHAP are also
required by a title V permit to be submitted, they must meet the title V certification requirement in
order to meet the reporting requirements of title V.
The commenters mentioned a specific requirement discussed in the preamble to the
proposal and found in Table 1 of the proposed and final landfills NESHAP regulation and in
§63.10(d)(5)(ii) of the NESHAP general provisions. This provision states that any time an
owner/operator takes an action during a SSM event which is not consistent with the procedures
specified in the affected source's SSM plan, the owner/operator shall report the actions taken for
that event within 2 working days after commencing actions inconsistent with the plan followed by
a letter within 7 working days after the end of the event. The commenters questioned whether
this requirement would satisfy the prompt reporting requirements of title V.
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The EPA responds that in terms of the prompt reporting of deviations, title V
requirements in 40 CFR 70.6(a)(3)(iii)(B) requires the permitting authority to define "prompt" in
relation to the degree and type of deviation likely to occur and the applicable requirements.
Therefore, it is the responsibility of the part 70 permitting authority to determine whether the
timing of reports under 40 CFR 63.10(d)(5)(ii) is sufficient to meet the permitting authority's
requirements for the prompt reporting of deviations. The permitting authority may decide for a
particular source or source category, or as a general matter, to impose more stringent reporting
requirements (e.g., type of report, content of report, and frequency of submission) than those
specified in an applicable requirement.
As noted above, the commenters stated that if the requirements in §63.10(d)(5)(ii) were
intended to fulfill the 'prompt reporting" requirements of title V, then it would be appropriate to
allow delegation of the reporting requirements to the State or local enforcement agencies, in
accordance with their part 70 programs. The EPA would like to clarify that the requirements in
§63.10(d)(5)(ii) are separate applicable requirements. They are part of the NESHAP general
provisions that apply to the landfills NESHAP, and to other NESHAP, and were designed to
assure compliance with SSM requirements; they were not designed to fulfill the prompt reporting
requirements of Title V. Moreover, in response to the last sentence of the above comment, EPA
would like to reiterate that part 70 permitting authorities are required to define "prompt" as
described above, but this does not alleviate the need for a source to comply with the provisions of
§63.10(d)(5)(ii). Finally, note that approved part 70 programs are not delegated programs, but
rather programs that have been submitted by a State or tribe to EPA for approval. Also, note that
State and local agencies may be delegated the authority to implement and enforce the landfills
NESHAP following the part 63 delegation procedures. See 40 CFR 60 subpart A, §§ 63.12 and
63.13 and subpart E §§63.90 through 63.99 for NESHAP delegation procedures and reporting
addresses.
Comment: One commenter (IV-D-09) recommended that EPA delete the requirement
mandating that area sources be required to obtain a title V permit and instead allow part 60 to
address title V integration. The commenter (FV-D-09) expressed concern that including this
section in the NESHAP causes confusion on the timing of the title V requirements because the
landfills EG/NSPS already contains title V permitting requirements for area sources. If EPA
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retains the requirement that area sources obtain a title V permit, the commenter (IV-D-09)
requested that EPA justify why area source landfills must be permitted.
Response: In response to this comment, title V requirements included in §63.1935 at
proposal have been deleted. The EPA further responds that section 502(a) of the CAA requires
any source, including an area source, subject to standards or regulations under section 111 or 112
of the CAA to operate in compliance with a title V permit after the effective date of any title V
permits program. This section states that the Administrator may promulgate regulations to
exempt one or more source categories, in whole or in part, from the requirements of the
subsection if the Administrator finds that compliance with title V requirements is impracticable,
infeasible, or unnecessarily burdensome on such categories. Thus, EPA does not need to justify
requiring title V permits. The CAA mandates criteria that must be met to justify an exemption for
any category of sources. According to section 502(a), however, the Administrator may not
exempt any major source from the requirements of title V.
Although section 502(a) requires that area sources subject to regulations under
section 111 or 112 be permitted unless the test in this section is met (i.e., the Administrator finds
that compliance with title V permitting requirements is impracticable, infeasible, or unnecessarily
burdensome), EPA is not applying this test to the landfills NESHAP.1 Rather, consistent with
what the commenter suggested, EPA is allowing the EG/NSPS for MS W landfills to address the
permitting requirements for area source landfills. This approach is justified because the same
universe of area source landfills would have been required to apply for a title V permit under the
final NESHAP (if the final rule were promulgated as proposed) as is currently subject to title V
permitting requirements under the NSPS for landfills and whatever plan is used to implement the
EG in an area (ie., an EPA-approved and effective State or tribal plan or the landfills Federal
plan). Moreover, most area source landfills which have a design capacity equal to or greater than
1 It is important to note that the determination regarding the permitting of area sources
under this NESHAP does not affect the permitting of area sources under other section 111 or 112
standards. Rather, to exempt area sources under either a section 111 or 112 standard, the test in
section 502(a) must be met. If commenters choose to try and meet this test when commenting on
a proposed section 111 or 112 standard, they must submit comments which document in detail the
ways in which title V requirements are impracticable, infeasible, or unnecessarily burdensome for
the source category in question.
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2.5 million Mg and 2.5 million m^ have already been required to apply for a title V permit due to
either the NSPS for landfifls, an EPA-approved and effective State or tribal plan for landfills, or
the landfills Federal plan. See 40 CFR 60.752(c), 60.32c(c), and 62.14352(e). See also the
"Clarification of title V Permitting Requirements" section of the EG/NSPS direct final rule
amendments for MSW landfills (63 FR 32743, 32746, June 16, 1998). In fact, unless the
owner/operator of a MSW landfill only recently commenced construction of the landfill and has
not yet been required to file a design capacity report (which the NSPS requires within 90 days
after the owner/operator commences construction), afl area source landfills of the design capacity
noted above and which meet the definition of new or existing under the EG/NSPS should have
already applied for a title V permit. As a result, EPA believes that it is unnecessary for area
sources to be required to apply for a title V permit as a result of the landfills NESHAP.
If a MSW landfill is a major source or is a part of a major source as defined under one or
more of title V's three major source definitions (section 112, section 302, and part D of title I of
the CAA),2 a title V application from such a source maybe due even earlier than the deadlines
established by 40 CFR part 60, subpart WWW, any EPA-approved and effective State or tribal
plan, or the landfills Federal plan. When a source is subject to title V for more than one reason
(e.g., meeting the title V applicability criteria in subpart WWW as well as having the potential to
emit one or more pollutants at major source levels), the 12-month time frame (or earlier if
required by the title V permitting authority) for submitting a title V application is triggered by the
requirement which first causes the source to become subject to title V. See CAA section 503(c)
and 40 CFR 70.3(a) and (b), 70.5(a)(l), 71.3(a) and(b), and71.5(a)(l). See also the
"Clarification of Title V Permitting Requirements" section of the EG/NSPS direct final rule
amendments for MSW landfills (63 FR 32743, 32746, June 16, 1998).3
2 For information on aggregating emissions units to determine what is a source under
title V, see the definition of major source in 40 CFR 70.2, 71.2, and 63.2. Nothing in this subpart
revises how affected sources are aggregated for purposes of determining whether an affected
source is a part of an area, nonmajor, or major source under any provisions of the Act or EPA's
regulations.
3 Consistent with the above, it is important to note that an application deadline once
established for a source cannot be superseded by another later application deadline unless the
title V program itself changes (e.g., a State program under 40 CFR part 70 becomes a Federal
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Given that most area source landfills subject to the NESHAP are already subject to the
requirements of title V, it is important to note the following. Incases where the owner/operator
of a landfill has submitted a timely and complete title V application,4 but the draft title V permit
has not yet been released by the permitting authority, the owner/operator must supplement his
title V application5 by incorporating the applicable requirements of the final landfills NESHAP in
accordance with 40 CFR 70.5(b) or 71.5(b). Additionally, if a landfill is a major source, or is a
part of a major source, and is covered by a title V permit with a remaining permit term of 3 or
more years on the promulgation date of the landfills NESHAP, the title V permitting authority
must complete a reopening of the source's title V permit to incorporate the requirements of the
landfills NESHAP within 18 months of the promulgation date of the final rule. See CAA
section 502(b)(9) and 40 CFR 70.7(f)(l)(i) and 71.7(f)(l)(i).
program under 40 CFR part 71).
4 A title V application should be submitted early enough for the permitting authority to
find the application either complete or incomplete before the title V application deadline. In the
event the application is found incomplete by the permitting authority, the source must submit the
information needed to make the application complete by the application deadline in order to
obtain an application shield. (An application shield allows a source to operate without being in
violation of title V prior to being issued a final title V permit.) To maintain an application shield,
a source must submit information as requested by the permitting authority and by the specified
deadline. See section 503(d) of the CAA, 40 CFR 70.5(a)(2), 70.7(b), 71.5(a)(2), and 71.7(b).
5 A title V application from a major source must address all emissions units at the title V
source, not just the section 111 or 112 emissions unit. See 40 CFR 70.3(c)(l) and 71.3(c)(l).
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TECHNICAL REPORT DATA
(please read instructions on the reverse before completing)
\. REPORT NO. 2.
EPA-453/R-02-014
4. TITLE AND SUBTITLE
Municipal Solid Waste Landfills: Background Information Document
For National Emission Standards for Hazardous Air Pollutants -
Public Comments and Responses
7. AUTHOR(S)
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Office of Air and Radiation
Research Triangle Park, North Carolina 2771 1
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Office of Air and Radiation
Research Triangle Park, North Carolina 2771 1
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
November 2002
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION R EPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D-0 1-081
13. TYPE OF REPORT AND PERIOD COVERED
Final Background Information
Document
14. SPONSORING AGENCY CODE
EPA 7200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Final national emissions standards for hazardous air pollutants (NESHA
are being promulgated under section 112 of the Clean Air Act. The sta
Register on November 7, 2000 and a supplemental proposal on May 23
public comments on the proposals received by EPA. It also contains El
P) for municipal solid waste landfills
ndards were proposed in the Federal
, 2002 . This document summarizes
'A's responses to the comments.
all
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS b. IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group
Air Pollution Control, Air Pollution Control,
Municipal Solid Waste Landfills Municipal Solid Waste Landfills
18 DISTRIBUTION STATEMENT 19. SECU RITY CLASS (This Report) 21 . NO. OF PAGES
UNCLASSIFIED 66
Release Unlimited
20. SECURITY CLASS (This Page) 22 PRICE
UNCLASSIFIED
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