&EFA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-453/R-94-021
December 1995
Air
Air Emissions from
Municipal Solid Waste
Landfills - Background
Information for Final
Standards and Guidelines
Final
EIS
-------
EPA-453/R-94-021
AIR EMISSIONS FROM MUNICIPAL
SOLID WASTE LANDFILLS -
BACKGROUND INFORMATION FOR
FINAL STANDARDS AND GUIDELINES
Emission Standards Division
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard. 12th Floor
Chicago. It 60604-3590
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
December 1995
-------
V
(
DISCLAIMER
This report is issued by the Emission Standards Division of the
Office of Air Quality Planning and Standards of the*Environmental
Protection Agency. Copies of this report are available through
the Library Services office (MD-35), U. S. Environmental
Protection Agency, Research Triangle Park, NC 27711, telephone
919-541-2777 (FTS 629-2777), or may be obtained for a fee from
the National Technical Information Service, 5285 Port Royal Road,
Springfield, VA 22161, telephone 703-487-4650.
Publication No. EPA-453/R-94-021
klk-85\04 11
-------
ENVIRONMENTAL PROTECTION AGENCY
Air Emissions from Municipal Solid Waste Landfills—
Background Information for Final Standards and Guidelines
Prepared by:
/Bruce C. Jordan (ate)
Emission Standards Division
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
1. The standards of performance and emission guidelines limit
emissions from new and existing municipal solid waste
landfills that emit over 50 Mg/yr of nonmethane organic
compounds (NMOC). Section 111 of the Clean Air Act
(42 U.S.C. 7411), as amended, directs the Administrator to
establish standards of performance and emission guidelines
for any category of source of air pollution that " causes
or contributes significantly to air pollution which may
reasonably be anticipated to endanger public health or
welfare."
2. Copies of this document have been sent to the following
Federal Departments: Office of Management and Budget,
Commerce, Interior, and Energy; the National Science
Foundation; and the Council on Environmental Quality.
Copies have also been sent to members of the State and
Territorial Air Pollution Program Administrators; the
Association of Local Air Pollution Control Officials; EPA
Regional Administrators; and other interested parties.
3. For additional information contact:
Ms. Martha Smith
Office of Air Quality Planning and Standards (MD-13)
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
Telephone: (919) 541-2421
4. Copies of this document may be obtained from:
U. S. EPA Library (MD-35)
Research Triangle Park, NC 27711
Telephone: (919) 541-2777
National Technical Information Service (NTIS)
5285 Port Royal Road
Springfield, VA 22161
Telephone: (703) 487-4650
klk-85\04
-------
TABLE OF CONTENTS
Page
LIST OF FIGURES vii
LIST OF TABLES viii
ACRONYMS, ABBREVIATIONS, AND MEASUREMENTS UNITS . .'\ X
CHAPTER
1.0 SUMMARY- 1-1
1.1 Summary of Standards, Emission Guidelines, and
Methods 1-2
1.1.1 Listing Under Section 111 of the Clean Air
Act 1-2
1.1.2 Applicability 1-4
1.1.3 Standards for Air Emissions from Municipal
Solid Waste Landfills 1-6
1.1.4 The Tier System Procedures 1-8
1.1.5 Compliance 1-12
1.1.6 Monitoring 1-14
1.1.7 Reporting and Recordkeeping 1-14
1.1.8 Design Specifications for Active Vertical
Collection Systems 1-17
1.1.9 Additional Information Specific to the
Emission Guidelines 1-18
1.1.10 Method 2E 1-19
1.1.11 Method 3C 1-21
1.1.12 Method 25C 1-22
1.2 Summary of Major Comments and Responses on the
Proposed standards and Emission Guidelines . . . 1-23
1.2.1 Response to EPA Solicitation of Comments . 1-23
1.2.2 Rationale for Significant Changes to
Regulation 1-29
1.3 Summary of Impacts of Promulgated Action and
Alternatives 1-48
1.3.1 Revisions to the Data Base 1-49
1.3.2 Revisions to the Modeling Methodology . . 1-51
1.3.3 Alternatives to Promulgated Action .... 1-54
1.3.4 Air Impacts 1-54
1.3.5 Other Environmental Impacts 1-59
2.0 SUMMARY AND RESPONSE TO PUBLIC COMMENTS RECEIVED ON THE
PROPOSED STANDARDS AND GUIDELINES 2-1
2.1 Introduction 2-1
2.2 General Comments 2-13
2.2.1 Definitions 2-13
2.2.2 Wording of the Standards 2-16
2.3 Selection of the Source Category 2-19
klk-85\0« IV
-------
TABLE OF CONTENTS (Continued)
2.3.1 Statutory Authority to Regulate 2-19
2.3.2 Health and Welfare Concerns 2-22
2.4 Selection of the Affected and Designated
Facilities 2-27
2.4.1 Exemptions from Control 2-31
2.4.2 Selection of the Tier Default Values . . . 2-40
2.4.3 Removal of Controls 2-50
2.5 Selection of the Pollutant to be Regulated . . . 2-52
2.6 Selection of Best Demonstrated Technology .... 2-55
2.6.1 Selection of Best Demonstrated Technology—
Passive Systems 2-57
2..6.2 Selection of the Emission Rate Cutoff . . 2-58
2.6.3 Requirements for Control Equipment .... 2-61
2.7 Format of the Standard 2-67
2.8 Nationwide Impacts 2-72
2.8.1 Cost Impacts 2-76
2.8.2 Secondary Air Impacts 2-83
2.8.3 Cost-Benefit Analysis 2-85
2.9 Monitoring and Testing 2-87
2.9.1 Monitoring 2-87
2.9.2 Nitrogen Monitoring 2-90
2.10 Modeling 2-95
2.11 Test Methods 2-100
2.11.1 Nonmethane Organic Compound Sampling
and Analysis 2-101
2.11.2 Method 2E 2-105
2.11.3 Method 3C 2-111
2.12 Design Specifications 2-112
2.12.1 Collection System Design . . 2-114
2.12.2 Determination of Well-Spacing 2-123
2.13 Operational Standards 2-128
2.14 Compliance 2-134
2.14.1 Compliance—Schedule 2-136
2.14.2 Compliance—System Shutdown 2-139
2.14.3 Compliance—System Expansion 2-142
2.15 Recordkeeping and Reporting 2-145
2.16 Regulatory Overlap 2-152
2.16.1 Superfund Interface 2-154
2.16.2 Prevention of Significant Deterioration
Interface 2-155
2.16.3 Subtitle D Interface 2-161
2.17 State Program Submittals 2-162
2.18 Policy Issues 2-163
2.18.1 Consideration of Methane 2-163
2.18.2 Consideration of Energy Recovery .... 2-167
2.18.3 Consideration of Materials Separation . . 2-180
2.19 Miscellaneous 2-181
3.0 ECONOMIC IMPACTS 3-1
3.1 Overview of Municipal Solid Waste Management . . . 3-2
3.1.1 Waste Generation 3-2
klk-85\04 V
-------
TABLE OF CONTENTS (Continued)
3.1.2 Waste Disposal 3-3
3.1.3 Requirements of Alternatives for
Promulgation 3-4
3.2 Characteristics of Affected Landfills 3-6
3.2.1 Design Capacity 3-6
3.2.2 Control Periods for Affected Landfills . . 3-10
3.2.3 Control Periods Prior to Closure .'*. . . . 3-13
3.3 Impacts of the Regulation 3-13
3.3.1 Enterprise Costs 3-17
3.3.2 Social Costs 3-33
3*3.3 Emissions Reduction and Cost Effectiveness 3-37
3.4 Costs of Regulations Affecting Landfills .... 3-45
3.5 Summary and Conclusions 3-48
3.6 References 3-53
klk-85\04 VI
-------
LIST OF FIGURES
Number Page
3-1 AFFECTED MODEL LANDFILL: LENGTH OF CONTROL PERIOD
UNDER THREE STRINGENCY LEVELS 3-5
3-2 EXPECTED IMPACTS OF COSTS OF REGULATIONS ON MUNICIPAL
WASTE COMBUSTORS \ . . . 3-46
3-3 EXPECTED IMPACTS OF COSTS OF REGULATIONS ON SANITARY
LANDFILLS 3-46
klJc-85\04 Vll
-------
LIST OF TABLES
Number Page
1-1 SUMMARY OF COST IMPACTS AND EMISSIONS REDUCTIONS OF
REGULATORY ALTERNATIVES OF THE NSPS 1-55
1-2 SUMMARY OF COST IMPACTS AND EMISSIONS REDUCTIONS OF
REGULATORY ALTERNATIVES OF THE EG 1-56
2-1 LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL SOLID WASTE
LANDFILLS 2-2
2-2 LIST OF PUBLIC HEARING SPEAKERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL SOLID WASTE
LANDFILLS 2-12
2-3 LIST OF WRITTEN COMMENTERS ON THE NOTICE OF
AVAILABILITY FOR THE PROPOSED STANDARDS OF
PERFORMANCE FOR MUNICIPAL SOLID WASTE LANDFILLS .... 2-14
3-1 SUMMARY INFORMATION FOR AFFECTED CLOSED AND EXISTING
LANDFILLS 3-7
3-2 SUMMARY INFORMATION FOR AFFECTED NEW LANDFILLS 3-9
3-3 LENGTH OF CONTROL PERIOD FOR AFFECTED CLOSED AND
EXISTING LANDFILLS 3-11
3-4 LENGTH OF CONTROL PERIOD FOR AFFECTED NEW LANDFILLS . 3-12
3-5 LENGTH OF CONTROL PERIOD PRIOR TO CLOSURE FOR
AFFECTED EXISTING LANDFILLS 3-14
3-6 LENGTH OF CONTROL PERIOD PRIOR TO CLOSURE FOR AFFECTED
NEW LANDFILLS 3-15
3-7 LENGTH OF CONTROL PERIOD PRIOR TO CLOSURE FOR AFFECTED
EXISTING LANDFILLS: PRIVATE LANDFILLS ONLY 3-16
3-8 NET PRESENT VALUE OF ENTERPRISE COSTS FOR AFFECTED
CLOSED AND EXISTING LANDFILLS 3-18
3-9 NET PRESENT VALUE OF ENTERPRISE COSTS FOR AFFECTED
NEW LANDFILLS 3-20
3-10 ANNUALIZED ENTERPRISE CONTROL COST PER Mg OF MSW FOR
AFFECTED EXISTING LANDFILLS 3-22
3-11 ANNUALIZED ENTERPRISE CONTROL COST PER Mg OF MSW FOR
AFFECTED EXISTING LANDFILLS WITH DATE OF CLOSURE BEFORE
1998: PRIVATE LANDFILLS ONLY 3-24
viii
-------
LIST OF TABLES (Continued)
Number Page
3-12 ANNUALIZED ENTERPRISE CONTROL COST PER Mg OF MSW FOR
AFFECTED EXISTING LANDFILLS DATE OF CLOSURE BETWEEN
1998 AND 2002: PRIVATE LANDFILLS ONLY %. . . . 3-25
3-13 ANNUALIZED ENTERPRISE CONTROL COST PER Mg OF MSW FOR
AFFECTED NEW LANDFILLS 3-27
3-14 ANNUALI-ZED ENTERPRISE CONTROL COST PER HOUSEHOLD FOR
AFFECTED EXISTING LANDFILLS . . 3-29
3-15 ANNUALIZED ENTERPRISE CONTROL COST PER HOUSEHOLD FOR
AFFECTED NEW LANDFILLS 3-30
3-16 NET PRESENT VALUE OF TOTAL RECORDKEEPING COSTS .... 3-32
3-17 NET PRESENT VALUE OF SOCIAL COSTS FOR AFFECTED CLOSED
AND EXISTING LANDFILLS 3-34
3-18 NET PRESENT VALUE OF SOCIAL COSTS FOR AFFECTED NEW
LANDFILLS 3-36
3-19 NET PRESENT VALUE OF EMISSIONS REDUCTIONS FOR
AFFECTED CLOSED AND EXISTING LANDFILLS 3-38
3-20 COST EFFECTIVENESS FOR AFFECTED CLOSED AND EXISTING
LANDFILLS 3-40
3-21 NET PRESENT VALUE OF EMISSIONS REDUCTIONS FOR AFFECTED
NEW LANDFILLS 3-42
3-22 COST EFFECTIVENESS FOR AFFECTED NEW LANDFILLS .... 3-44
3-23 SUMMARY OF DIFFERENCES BETWEEN THE PROPOSED RULE AND
FINAL RULE OPTIONS at the 100 Mg PER YEAR
STRINGENCY LEVEL 3-51
kli-85\04 IX
-------
ACRONYMS, ABBREVIATIONS, AND MEASUREMENT UNITS
Acronyms
AEERL
APCD
AQRV
ASCE
BACT
BAT
BDT
BID
BFI
CAA
GARB
CEM
CERCLA
CFC
CFR
CH4
CO
CO2
CTC
The EPA Office of Research and Development's Air and
Energy Engineering Research Laboratory
air pollution control device
air quality related value
American Society of Civil Engineers
best available control technology
best available technology
best demonstrated technology
Background Information Document
Browning-Ferris Industries
Clean Air Act
California Air Resources Board
continuous emission monitor
Comprehensive Environmental Response, Compensation, and
Liability Act
chlorof luorocarbon
Code of Federal Regulations
Methane
nonmethane organic compounds concentration
carbon monoxide
carbon dioxide
Control Technology Center
kUt-85\OA
-------
ACRONYMS, ABBREVIATIONS, AND MEASUREMENT UNITS (CONTINUED)
Acronyms
EG emission guidelines
EIS Environmental Impact Statement
EMB Emission Measurement Branch
EMCON (company name; not an acronym)
EPA U. S. Environmental Protection Agency
BSD Emission Standards Division
EXISCLOS Data base of landfills opening in 1987 and closing in
1992
FLM Federal land manager
FID flame ionization detector
FR Federal Register
GC gas chromatograph
HAP hazardous air pollutant
HOPE high density polyethylene
HON hazardous organic NESHAP
H2O water
I.e. internal combustion
IGBP International Geosphere-Biosphere Programme
ISO Interim Standard Offer
k methane generation rate constant, year"1
LAEEM Landfill Air Emissions Estimation Model
LAER lowest achievable emission rate
LFG landfill gas
klk-85\04 XI
-------
ACRONYMS, ABBREVIATIONS, AND MEASUREMENT UNITS (CONTINUED)
Acronyms
LLRW low level radioactive waste
L0 methane generation potential, m3/Mg
MACT maximum achievable control technology
MIR maximum individual lifetime risk
MSW municipal solid waste
MWC municipal waste combustor
N2 nitrogen
NAAQS national ambient air quality standard
NAPCTAC national air pollution control techniques advisory
committee
NESHAP national emission standards for hazardous air
pollutants
NIMBY not in my backyard
NMOC nonmethane organic compounds
NOX nitrogen oxides
NPL National Priorities List
NPV net present value (the value at one point in time of a
flow of values across time)
NRC Nuclear Regulatory Commission
NSPS new source performance standards
NSR new source review
NSWMA National Solid Wastes Management Association
NTIS National Technical Information Service
klk-85\04
xii
-------
ACRONYMS, ABBREVIATIONS, AND MEASUREMENT UNITS (CONTINUED)
Acronyms
NYSDEC New York State Department of Environmental Conservation
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
OSW Office of Solid Waste
OVA organic vapor analyzer
°2 oxygen
PCS polychlorinated biphenyls
PCDD polychlorinated dibenzo-p-dioxins
PCDF polychlorinated dibenzo furans
pH hydrogen-ion concentration
PIC products of incomplete combustion
PM particulate matter
PM10 particulate matter smaller than 10 microns
POHC polycyclic organic hydrocarbon
PSD prevention of significant deterioration
PVC polyvinyl chloride
RCRA Resource Conservation and Recovery Act
RFA Regulatory Flexibility Analysis
RIA Regulatory Impact Analysis
RIP refuse-in-place
ROD Records of Decision
ROI radius of influence
kUc-85\04
xiii
-------
ACRONYMS, ABBREVIATIONS, AND MEASUREMENT UNITS (CONTINUED)
Acronyms
RRF resource recovery facilities
• \
SBA Small Business Act
SCAQMD South Coast Air Quality Management District
SDB Standards Development Branch
SIP State implementation plan
SC>2 sulfur dioxide
SOX sulfur oxides
SWANA Solid Waste Association of North America
TAG technical advisory group
TCD thermal conductivity detector
TGNMO total gaseous nonmethane organics
TOC total organic carbon
TSDF treatment, storage and disposal facility
VOC volatile organic compound
WMA Waste Management, Inc.
WCRP World Climate Research Programme
Abbreviations and Measurements Units
Btu = British thermal unit
°C = degrees Celsius
dscf = dry standard cubic foot (14.7 psi, 68 °F)
dscm - dry standard cubic meter (760 mmHg, 20 °C)
kli-85\04
xiv
-------
ACRONYMS, ABBREVIATIONS, AND MEASUREMENT UNITS (CONTINUED)
Abbreviations and Measurements Units
°F = degrees Fahrenheit
ft - foot
ft3 = cubic foot
in. = inch
J — joules
km = kilometers
In = natural log
m = meter
mm = millimeter
MM = million
ml/min = milliliter per minute
Mg = megagram
MW = megawatt
m3 = cubic meter
mg = milligram
ppm = parts per million
ppmv = parts per million by volume
ppmvd = parts per million by volume, dry
psi = pounds per square inch
tons/yr = tons per year
yr = year
$/Mg = dollars per megagram
$/ton = dollars per ton
kIk-BSW
XV
-------
1.0 SUMMARY
On May 30, 1991, the Environmental Protection Agency
(EPA) proposed new source performance standards (NSPS) for new
municipal solid waste (MSW) landfills and emission guidelines
(EG) for existing MSW landfills (56 FR 24468) under the
authority of sections lll(b) and (d) of the Clean Air Act
(CAA). Public comments were requested on the proposed
standards and guidelines. Comment letters were received from
60 commenters including industry representatives, governmental
entities, environmental groups, and private citizens. A
public hearing was held in Research Triangle Park, North
Carolina, on July 2, 1991. This hearing was open to the
public and five persons presented oral testimony on the
proposed NSPS and EG.
On June 21, 1993, a supplemental notice of data
availability to the May 30, 1991 proposal appeared in the
Federal Register (58 FR 33790). The notice announced the
availability of additional data and information on changes in
the EPA's modelling methodology being used in the development
of the final NSPS and EG for MSW landfills. Public comments
were requested on the new data and comment letters were
received from seven commenters.
Changes have been made to the NSPS and EG in response to
comments and as a result of additional analyses completed
since proposal. The final NSPS and EG are summarized in
section 1.1. The major changes made to the proposed rules are
summarized in section 1.2. A summary of the impacts of the
NSPS and EG is presented in section 1.3. All of the written
and verbal comments that were submitted regarding the proposed
kli-85\0* 1-1
-------
rules and notice of data availability are summarized in
chapter 2. The revised economic impacts analysis is presented
in chapter 3. The summary of comments and responses and
revised economic impacts serve as the basis for the revisions
made to the NSPS and EG between proposal and promulgation.
1.1 SUMMARY OF STANDARDS, EMISSION GUIDELINES, AND METHODS
1.1.1 Listing Under Section 111 of the Clean Air*Act
Section 111(b)(1)(A) of the CAA provides:
The Administrator shall, within 90 days after
[December 31, 1970], publish (and from time to time
thereafter shall revise) a list of categories of
stationary sources. He shall include a category of
sources in such list if in his judgment it causes,
or contributes significantly to, air pollution which
may reasonably be anticipated to endanger public
health or welfare.
Section lll(b)(1)(B) requires the Administrator to promulgate
"standards of performance for new sources within such
category."
Concurrently with promulgating the landfills NSPS and EG,
the Administrator had added the source category MSW landfills
to the priority list in 40 CFR 60.16 because in the judgment
of the Administrator it contributes significantly to air
pollution which may reasonably be anticipated to endanger
public health and weliare.
MSW landfill emissions, commonly called landfill gas
(LFG), are generated by naturally occurring methanogens that
decompose complex organic materials into organic compounds of
lower molecular weight. Landfill gas consists primarily of
carbon dioxide (C02), methane, and non-methane organic
compounds (NMOC). The methane strips or transports NMOC
through the landfill to the atmosphere. Evidence from the EPA
and State studies indicates that LFG released by MSW landfills
has adverse effects on both public health and welfare.
The first specific health and welfare effect of concern
is ozone formation. Ground level ozone is created by sunlight
klk-85\0* 1-2
-------
acting on nitrogen oxides (NOX) and NMOC in ambient air.
Ozone may lead to health effects such as alteration of
pulmonary function, aggravation of preexisting respiratory
disease, damage to lung structure/ and adverse effects on
blood enzymes, the central nervous system, and the endocrine
system. Ozone also presents welfare effects such as reduced
plant growth, reduced crop yield, necrosis of plant tissue,
and deterioration of certain synthetic materials, such as
rubber.
A second concern is the cancer and noncancer health
effects of various NMOC. Many NMOC identified in LFG are
either known or suspected carcinogens, and have the potential
to produce noncancer health effects as well, such as adverse
effects on the kidneys, liver, and central nervous system.
Many of the NMOC are Hazardous Air Pollutants (HAP's) as
defined under section 112(b) and listed by the Source Category
List under section 112(c) of the CAA, as amended in 1990
(57 FR 31576, July 16, 1992). The EPA intends to evaluate MSW
landfills as a source category under this section.
Additional public welfare concerns are odor nuisance from
gaseous decomposition, and the potential for methane
migration, both on-site and off-site, which may lead to
explosions or fires. Explosive gas control is already
addressed under S 258.23 of the Resource Conservation and
Recovery Act (RCRA) Subtitle D rules (40 CFR part 258);
however, a landfill gas control system will significantly
reduce the explosion potential. These concerns are not only
nuisances in and of themselves, but can adversely affect
adjacent property values. And, as discussed in the preamble
to the proposal, MSW emissions contribute to global methane
emissions, a major greenhouse gas. These methane emissions
also present a welfare concern.
Although one commenter suggested that LFG emissions
should be regulated under RCRA authority, the EPA continues to
consider Section 111 NSPS and EG to be the appropriate
statutory approach for regulating these emissions because the
kli-85\0* 1-3
-------
adverse health and welfare effects of concern result from air
emissions. Therefore, the final notice added MSW landfills as
a source cat ory for regulation under Section lll(b)(1)(A) of
the CAA to th« priority list in 40 CFR 60.16.
1.1.2 Applicability
The affected facility under the NSPS is each new MSW
landfill. Municipal solid waste landfills are also subject to
the requirements of RCRA (40 CFR part 258). A new MSW
landfill is a landfill for which construction, modification,
or reconstruction commences on or after the proposal date of
May 30, 1991 or that began accepting waste on or after that
date.
The emission guidelines require control for certain
exist g MSW landfills. An existing MSW landfill is a
landfill for which construction commenced prior to May 30,
1991. An existing MSW landfill may be active, i.e., currently
accepting waste, or having additional capacity available to
accept waste, or may be closed, i.e., no longer accepting
waste nor having available capacity for future waste
deposition. The designated facility under the emission
guidelines is each existing MSW landfill that has accepted
waste since November 8, 1987.
Section 60.752 of the NSPS requires affected and
designated MSW landfills having design capacities below
2.5 million megagrams (Mg) or 2.5 million cubic meters (m3) to
file a design capacity report. Affected and designated MSW
landfills having design capacities greater than or equal to
2.5 million Mg or 2.5 million m3 are subject to the additional
provisions of the standards or guidelines.
Some changes have been made to the definitions in both
subpart WWW and subpart Cc so that definitions in these
subparts would be consistent with definitions in regulations
of part 258 of title 40, Criteria for MSW Landfills Under
RCRA.
MSW landfills are also listed under section 112(c) as a
source category (57 FR 31576, July 16, 1992). Promulgation of
kli-85\0* 1-4
-------
section 112 emission standards for the MSW landfills source
category is currently scheduled for not later than
November 15, 2000 (58 FR 63941, 63954, Dec. 3, 1993).
Section lll(d)(1)(A) was twice amended by the 1990 Clean
Air Act Amendments. Pub. L. 101-549, section 302(a), directed
the substitution of "7412(b)M for "7412(b)(1)(A)," and Pub. L.
101-549, section 108(g), substituted "or emitted from a source
category which is regulated under section 7412 of this title"
for "or 7412(b)(1)(A)." Title 42 of the U.S. Code adopts the
amendment* of section 108(g) with the explanation that
section 302(a) could not be executed because of the prior
amendment by section 108(g). 42 U.S.C. section 7411 (Supp.IV
1993). The EPA also believes that section 108(g) is the
correct amendment because the Clean Air Act Amendments revised
section 112 to include regulation of source categories in
addition to regulation of listed hazardous air pollutants, and
section 108(g) thus conforms to other amendments of
section 112. The section not adopted by title 42, 302(a), on
the other hand, is a simple substitution of one subsection
citation for another, without consideration of other
amendments of the section in which it resides, section 112.
Thus EPA agrees that CAA section lll(d)(1)(A) should read
"[t]he Administrator shall prescribe regulations which . . .
establish[] standards of performance for any existing source
for any air pollutant . . . which is not . . . emitted from a
source category which is regulated under section 112."
Thus, as amended by the 1990 Clean Air Act Amendments,
section lll(d)(1)(A) allows EPA to establish NSPS without
prescribing emission guidelines for existing sources if the
designated air pollutant is 1) a pollutant for which air
quality criteria have been issued, 2) included on a list
published under section 108(a), or 3) emitted from a source
category regulated under section 112. That is not the case
here because landfill gas, the designated air pollutant for
MSW landfills, is not a pollutant which satisfies any of these
criteria. First, landfill gas is a composite of many
klk-85\04 1-5
-------
compounds, including some compounds for which air quality
criteria have been issued and which are included on a list
published under section 108(a) (e.g. volatile organic
compounds (VOC), which are ozone precursors), although other
landfill gas components, such as methane and methylene
chloride, are not compounds for which air quality criteria
have been issued and are not included on a list published
under section 108(a). Moreover, landfill gas itself is not an
air pollutant for which air quality criteria have been issued,
and landfill gas itself is not included on a list published
under section 108(a).
Finally, landfill gas is not emitted from a source
category that is actually being regulated under section 112.
Although MSW landfills is a source category listed under
section 112(c), existing MSW landfills will not actually be
regulated under section 112 until an emission standard is
proposed under section 112(d). Because a section 112 emission
standard for MSW landfills is not scheduled for promulgation
until the year 2000, MSW landfill emissions will not actually
be regulated under section 112 until that time. In addition,
some components of landfill gas are not hazardous air
pollutants listed under section 112(b) and thus will not be
regulated under a section 112(d) emission standard.
Therefore, EPA is establishing emission guidelines under
section lll(d)(1)(A) for sources of the designated pollutant
landfill gas.
1.1.3 Standards for Air Emissions from Municipal Solid Waste
Landfills
The final standards and EG for MSW landfill emissions
require the periodic calculation of the annual NMOC emission
rate at each affected or designated facility with a maximum
design capacity greater than or equal to 2.5 million Mg or
2.5 million m3.
The best demonstrated technology (BDT) (for both the NSPS
and the EG) requires the reduction of MSW landfill emissions
from new and existing MSW landfills emitting 50 Mg per year
klk-85\0* 1-6
-------
(Mg/yr) of NMOC or more with: (1) a well-designed and
well-operated gas collection system and (2) a control device
capable of reducing NMOC in the collected gas by
98 weight-percent.
A well-designed and well-operated collection system
would, at a minimum: (1) be capable of handling the maximum
gas generation rate; (2) have a design capable of"monitoring
and adjusting the operation of the system; (3) be able to
collect gas effectively from all areas of the landfill that
warrant control; and (4) be able to expand by the addition of
further collection system components to collect gas from new
areas of the landfill as they require control.
The BDT control device is a combustion device capable of
reducing NMOC emissions by 98 weight-percent. While energy
recovery is strongly recommended, the cost analysis is based
on open flares because they are applicable to all affected and
designated facilities regulated by the standards and emissions
guidelines. If an owner or operator uses an enclosed
combustion device, the device must demonstrate either the
98-percent reduction or reduction of the outlet NMOC
concentration to 20 ppmvd as hexane at 3-percent oxygen as
demonstrated by Method 25 or Method 18 of appendix A of 40 CFR
part 60 (for the compounds listed in the most recent
"Compilation of Air Pollutant Emission Factors" (AP-42)).
Alternatively, the collected gas may be treated for subsequent
sale or use, provided that all emissions from any atmospheric
vent from the treatment system are routed to a control device
meeting either specification above.
The standards require that three conditions be met prior
to removal of the collection and control system: (1) the
landfill must be permanently closed under the requirements of
40 CFR 258.60; (2) the collection and control system must have
been in continuous operation a minimum of 15 years; and
(3) the annual NMOC emission rate routed to the control device
must be less than the emission rate cutoff of 50 Mg/yr on
three successive dates, between 90 and 180 days apart, based
ktt-85\0* 1-7
-------
upon the site-specific landfill gas flow rate and average NNOC
concentration.
A new section of the regulation, S 60.753, contains
provisions regarding the operational standards for collection
and control systems. These provisions include:
(1) collection of gas from each active area, cell, or group of
cells in which non-asbestos degradable solid waste has been
placed for a period of 5 years or more and from each closed
area or area at final grade in which solid waste has been
placed for at least 2 years; (2) operation of the collection
system with each wellhead under negative pressure;
(3) operation with a nitrogen level less.than or equal to
20 percent or an oxygen level less than or equal to 5 percent;
(4) operation with a landfill gas temperature less than 55 °C;
(5) a requirement that the collection system be operated to
limit the surface methane concentration to less than 500 ppm
over the landfill; (6) venting of all collected gases to a
treatment or control device; and (7) operation of the control
device at all times when the collected gas is routed to the
control device.
1.1.4 The Tier System Procedures
The tier system is used to determine if and when an
affected or designated landfill needs to install a gas
collection system. As an example, a relatively new landfill
may produce landfill gas above the emission rate cutoff at
some time in the future; the annual emission estimate in the
tier calculations will indicate when this time has come.
Section 60.754 of the NSPS provides the tier system for
calculating whether the NMOC emission rate is less than
50 Mg/yr, using a first order decomposition rate equation.
Section 60.34c of the EG also requires calculation of the NMOC
emission rate using the tier system provided in the NSPS. Any
owner or operator that already has or intends to install
controls (to full compliance) without modeling the emissions
does not need to use this tier system.
klk-85\04 1-8
-------
The final NSPS and EG allow the mass of segregated, non-
degradable waste in a landfill to be subtracted from the total
mass prior to the NMOC emission rate calculation, provided
that the non-degradable nature of the waste, location, and
mass are recorded and included with the emission rate report.
Tier 1—Under Tier 1, the landfill owner or operator
combines readily available data such as landfill "age and waste
acceptance rate with default values of 0.05/yr for the methane
generation rate constant (k), 170 m3/Mg for the methane
generation potential (L0) and 4,000 parts per million by
volume (ppmv) for the NMOC concentration. The default values
for these parameters were-changed between proposal and
promulgation. The default values for k, Lo, and NMOC
concentration are within an acceptable range and were selected
to minimize the number of landfills that are actually emitting
more than 50 Mg/yr of NMOC, but would be estimated, using the
default values, to emit less than the cutoff. In selecting
the default values in this way, Tier 1 estimates emissions
from some landfills to be greater than the emission rate
cutoff when in reality they are not. Therefore, the landfill
can use site-specific information from Tier 2 and Tier 3 to
show that the revised emission estimates are below the cutoff.
For those landfills where the Tier 1 calculation results in an
emission estimate below 50 Mg/yr of NMOC, the rules would not
require collection and control systems, but would require
periodic recalculation of emissions until closure. For those
landfills whose Tier l calculations result in an NMOC emission
rate equal to or greater than 50 Mg/yr, the owner or operator
must either install collection and control systems or must
perform the field measurement procedures detailed in Tier 2 to
better estimate the site-specific NMOC emission rate for
comparison with the 50 Mg/yr cutoff.
Tier 2—In Tier 2, the landfill owner or operator
conducts sampling to determine a site-specific NMOC
concentration to substitute for the default NMOC concentration
of 4,000 ppmv in the Tier 1 equation. The standards provide
kUc-85\04 1-9
-------
sampling procedures for NHOC concentration, and the samples
are to be analyzed using Method 25C. Unlike the proposal, the
number of samples depends on the size of the landfill. Two
samples must be taken from each hectare up to a maximum of 50
samples. More than 2 per hectare or more than 50 samples may
be taken; however, all samples taken must be used in the
analysis. If the NMOC emission rate calculated Using the
site-specific NMOC concentration is equal to or greater than
50 Mg/yr, the owner or operator must install controls or
perform the field testing procedures detailed in Tier 3 to
better estimate the NMOC emission rate for comparison with the
50 Mg/yr cutoff.
If the average NMOC concentration from the samples
results in a calculated NMOC emission rate below the emission
rate cutoff of 50 Mg/yr, the standards require retesting of
NMOC concentration levels for use in the tier calculations
every 5 years. Due to the increase in the design capacity
exemption and the decrease in the emission rate cutoff, the
proposed provision for a statistical analysis to allow
10 years between retesting the NMOC concentration levels has
been deleted from the final rule. These changes to the rule
greatly reduce the number of landfills that would perform
Tier 2 measurements. The lower emission rate cutoff will
require controls to be applied sooner, and the change
simplifies implementation of the rule.
Tier 3—Under Tier 3, a site-specific methane generation
rate constant, k, is determined by gas flow testing to
substitute for the default k value of 0.05/yr in the equation.
Tier 3 distinguishes between MSW landfills with known
histories of where and when MSW was deposited and those with
little known history. Cluster wells are used when the history
is known, and equal-volume wells when the history is not
known. Cluster wells are groupings of three wells fairly
close together, whereas equal-volume wells are evenly spaced
throughout the landfill. For landfills with known histories,
Method 2E provides guidance on where to locate cluster wells
kli-85\(H 1-10
-------
to provide good estimates of k. However, if landfill history
is not known, the equal-volume well method produces estimates
with greater statistical confidence than cluster wells.
Tier 3 testing is performed using Method 2E, which is a final
method promulgated in the rule. The NSPS requires that the
NMOC concentration obtained in Tier 2 be used in all Tier 3
calculations. '*
Landfills where the NMOC emission rate calculated in
Tier 3 is below 50 Mg/yr need not install collection and
control systems, but must still retest the concentration of
NMOC every 5 years as required in Tier 2. The value for k
obtained in Tier 3 is to be used for all subsequent
calculations.
Landfills with a calculated emission rate greater than
50 Mg/yr, after substituting both a site-specific NMOC
concentration and a site-specific k, must install a collection
and control system.
Calculation of NMOC and Flow for On-Line Collection
Systems—For landfills which have a collection system already
installed, the standards provide formulas and procedures for
calculating NMOC emissions using samples and gas flow data
obtained from an existing collection system. These formulas
can be used by landfills that are presently collecting
landfill gas to show that their NMOC emissions are less than
the emission rate cutoff. These formulas and procedures can
also be used by landfills that have installed collection and
control systems to comply with the rule when the emissions
have subsided to the extent that the owner or operator would
like to determine if the NMOC emissions are now less than the
emission rate cutoff. Landfill owners or operators using
direct sampling would have to demonstrate that there is not
excessive air infiltration into their system, and that there
was no positive pressure at any wellhead when sampling and gas
flow tests were performed. The landfill owner or operator
must also document that the collection system is effectively
kli-85\0* 1-11
-------
collecting landfill gas from all gas producing areas of the
landfill.
Using samples and gas flow data from an existing system
is the only method allowed for determining that the NMOC
emission rate is less than 50 Mg/yr when owners or operators
want to remove control systems. The formula and procedures
for sampling and determining the NMOC concentration and the
gas flow directly from the system provided in S 60.754(b) of
the final NSPS must be used when calculating the NMOC emission
rate for the purpose of system removal. The tier approach is
not permitted once a collection system has been installed,
because direct sampling procedures provide the most accurate
estimate of the NMOC emission rate and are readily available
after system installation.
1.1.5 Compliance
Section 60.755 of the NSPS provides formula and/or
procedures for determining compliance with the standards for
collection systems and control devices provided in
S S 60.752(b)(2)(ii) and 60.753.
To design the collection system to handle the maximum
expected gas flow rate, the maximum expected gas generation
rate is calculated using the default values for k and Lo; if
Method 2E has been performed, the owner or operator must use
the site-specific k. In S 60.755(a)(1) of the final standard,
changes have been made to allow calculation of the maximum gas
generation rate for sites with known and unknown year-to-year
solid waste acceptance rates, and for a specific intended
equipment use period, if the owner or operator intends to use
the equipment for a period of time other than 15 years.
Section 60.755(a)(2) was revised to allow the use of any
collection system approved by the regulatory authority capable
of controlling and extracting gas from all required portions
of the landfill. The design plan must demonstrate that there
is a sufficient density of gas collectors to meet all
operational and performance standards.
kLk-85\0* 1-12
-------
Section 60.755(a)(3) requires that adjustments to the gas
collection header and wellhead valves be made to maintain
negative pressure. A time schedule was added to this section
that requires an additional well to be installed if negative
pressure cannot be achieved within a specified time period.
Several commenters maintained that 30 days was not
adequate time to establish negative pressure at the wellhead
after initial start-up of the collection and control system.
Upon further evaluation, the rules were modified to allow
180 days to establish negative pressure at the wellhead after
initial start-up of the collection and control system.
A new paragraph (a)(6) was added to S 60.755, requiring
that owners and operators of MSW landfills seeking to
demonstrate compliance with the standards for collection
systems must demonstrate that off-site migration is being
controlled.
As discussed later in the summary of major changes to the
rule section, three additional compliance provisions were
added to S 60.755. These provisions are: (1) a 60 day time
limit for the extension of the collection system into solid
waste that has reached an age of 5 years if active, 2 years if
closed or at final grade [in S 60.755(b)]; (2) procedures and
instrument specifications for monitoring surface
concentrations of methane, including the installation of
additional wells, if necessary; and (3) allowable downtime for
start-up, shutdown and malfunction of collection or control
equipment. The reader is directed to sections 1.2.3.4 through
1.2.3.6 of this BID for a discussion of these provisions.
Owners and operators seeking to demonstrate compliance
with S 60.752(b)(2)(iii) are required to use open flares
operated in compliance with 40 CFR 60.18, or to conduct an
initial performance test using Method 25 or Method 18
(speciated for compounds listed in AP-42) to demonstrate
either 98 percent NMOC emission reduction or, for enclosed
combustors, a concentration of 20 ppmvd NMOC as hexane at
3 percent oxygen at the outlet.
klk-85\04 1-13
-------
1.1.6 Monitoring
Each MSW landfill installing a collection system must
monitor the nitrogen or oxygen concentration and the
temperature of the LFG at each well on a monthly basis. Also,
the owner or operator can propose and use an alternative
method for detecting infiltration (such as monitoring for
carbon monoxide, the methane to carbon dioxide ra£io, or the
composting ratio) provided that the method is approved by the
permitting authority.
When an enclosed combustion device is used for control,
the temperature and the gas flow to (or bypass of) the control
device must be monitored. When an open flare is used for gas
control, the pilot flame (or flare flame itself) must be
monitored using a heat sensing device to demonstrate the
continuous presence of a flame, and the gas flow to (or bypass
of) the control device must be monitored.
Sections 60.756(d) and (e) provide that for each
collection system and for any control device other than an
open flare or an enclosed combustion device used, the owner or
operator must provide to the regulatory authority information
describing the operation of the system and/or device,
parameters that would indicate proper performance and
monitoring procedures.
1.1.7 Reporting and Recordkeepina
The final standards require owners and operators of all
affected facilities to submit notifications of construction,
modification, or reconstruction as required under the General
Provisions (40 CFR 60.7). This notification must include the
maximum design capacity of the landfill, date of anticipated
initial waste acceptance, and the anticipated solid waste
acceptance rate. The EPA expects that the design capacity
calculation required in the notification of construction
report will exclude a large majority of all landfills from the
further provisions of the standards, and will alert
enforcement personnel to the remaining population of landfills
klk-85\0* 1-14
-------
that may be required to install collection and control systems
in the future.
Notification of construction from HSV landfills with
initial design capacities less than 2.5 million Mg or
2.5 million m3 fulfills all of the recordkeeping and reporting
requirements for these landfills unless the design capacity is
revised above the limit in the future. x
Each owner or operator of an MSW landfill with a design
capacity equal to or greater than 2.5 million Mg or
2.5 million m3 must install a collection and control system or
submit an annual calculation demonstrating that the NMOC
emission rate is less than 50 Mg/yr. Alternatively, the owner
or operator could elect to provide an estimate of the NMOC
emission rate for each of the next 5 years using the equations
provided in § 60.754 and an estimate of the solid waste
acceptance rate for each of the 5 years, provided that the
estimated NMOC emission rate does not exceed 50 Mg/yr in any
of the 5 years reported. The initial annual NMOC emission
rate report or 5-year estimate must be submitted within
90 days of start-up, i.e., solid waste acceptance.
The owner or operator must also update and re-submit the
5-year estimate within at least 5 years of submittal of the
first 5-year estimate. Additionally, if the actual waste
acceptance rate exceeds the estimated waste acceptance rate in
any of the 5 years for which an estimated NMOC emission rate
was reported, a revised estimate must be submitted. The
5-year period reported in the revised 5-year estimate would
commence when the new report is submitted.
After the NMOC emission rate calculated using Tier 1
equals or exceeds 50 Mg/yr, § 60.757(c) of the final standards
requires the submission of a collection and control system
design plan for approval within a year. A landfill owner or
operator may elect to perform the Tier 2 sampling or Tier 3
testing to generate a site-specific NMOC concentration or gas
generation rate to use for the calculation of a more accurate
NMOC emission rate. In either case, the recalculated emission
klk-85\04 1-15
-------
rate must be reported within 1 year of the initial Tier 1
calculation as well. If the recalculated emission rate still
equals or exceeds 50 Mg/yr, the collection system design plan
must also be submitted within the same 1-year time period in
which the Tier 1 calculation equaled or exceeded 50 Mg/yr.
After the 1-year described above, a landfill will have
18 months to install an approved collection system.
Collection system design plans should require 180 days for
review and revision; therefore, 1 year is allowed for
installation of the collection system. As discussed in the
proposal preamble, the EPA believes this approach to be fair
for either design approach (see proposal preamble section
III.H). An owner or operator using an approved design is
allowed an additional 180 days to submit the initial
performance test.
After the collection and control system has been
installed and the initial performance test has been completed
and submitted, S 60.757(f) of the NSPS and S 60.35C of the EG
require the submission of annual compliance reports which
include: (1) any period in which the value of any of the
monitored operating parameters falls outside the acceptable
ranges; (2) all periods when the gas stream was diverted from
the control device; (3) periods when collection or control
equipment was not operating; (4) the location of all
exceedances of the 500 ppm methane limit during the quarterly
surface monitoring and the highest level recorded at that
location in the subsequent monitoring period; and (5) the date
of installation and location of each well added to the system
during the period.
The NSPS and EG also require that certain types of
records be maintained. Records of the accumulated solid waste
in place, collection system design (including planned as well
as current well or trench layout), control device vendor
specifications, the initial and most recent performance test
results, and the monitoring parameters established during the
initial performance test must be maintained as long as the
klk-85\0* 1-16
-------
collection system and control devices are required to be
operated.
Any replacement of system components which results in a
change in the level of any parameter that is monitored to
demonstrate 98 percent NMOC destruction efficiency must be
entered into this permanent record, and reported in the next
annual compliance report. Monitoring records and"all data and
calculations from each annual compliance report must be
maintained for at least 5 years following the date of such
reports. '
1.1.8 Design Specifications for Active Vertical Collection
Systems
In the final standards, provisions are given that design
plans must specify methods for siting active vertical
collection wells throughout the landfill, but does not contain
prescriptive design plans. Instead, all site-specific design
plans must be approved by the Administrator (in most cases the
State or local regulatory agency will be delegated authority
to implement the NSPS and EG, including the approval of design
plans). Wells must be placed so that gas is collected from
all active areas of the landfill that have contained solid
waste for at least 5 years and all closed areas or areas at
final grade that have contained solid waste for at least
2 years.
The final standards have been changed to allow the owner
or operator to consider the site-specific equipment life when
sizing the collection system blower. In this way, blowers may
be used over shorter periods of time or exchanged to more
closely track gas flow rate without being out of compliance.
The formula for determining maximum flow rate has been revised
to accommodate both active and closed landfill conditions.
The final NSPS distinguishes between areas that are
nonproductive because of the age of the solid waste and those
that are non-degradable due to the inorganic nature of the
solid waste when allowing such areas to be excluded from the
collection system. Nonproductive areas are excluded due to
klk-85\04 1-17
-------
low NMOC emissions, and all such excluded areas must
collectively contribute less than 1 percent of total NMOC
emissions. Non-degradable areas are excluded because they
have no emission potential, and only if (1) such materials are
deposited in a segregated area not overlying productive solid
waste, and (2) the location, volume, mass and nature of the
excluded materials are documented and reported.
The final EG requires that existing landfills subject to
control must install collection systems that meet the MSPS
•
standards for collection systems. The collection system must
satisfy all the criteria provided in S 60.752(b)(2) and be
approved by the Administrator.
1.1.9 Additional Information Specific to the Emission
Guidelines
Under the final EG, States are required to submit plans
for existing sources and to provide for implementation and
enforcement of emission standards for existing HSW landfills.
The EPA has determined that these are health-based guidelines,
meaning that state plans must be at least as stringent as the
EG. The final EG have been modified to reference the
provisions of the NSPS for the specification of approved
design plans for the gas collection and control system.
The final emission guidelines stipulate that the existing
MSW landfills emitting NMOC of 50 Mg/yr or greater when the
State plan is approved must achieve compliance with the
guidelines for collection and control systems within 3 years
from the time of promulgation of the State regulations. This
time period allows 2.5 years for further site-specific testing
(if elected by the owner or operator), preparation and review
of a collection system design plan, and installation of the
collection and control system; and 180 days for a performance
test.
In the case of existing MSW landfills whose NMOC emission
rates reach the emission rate cutoff of 50 Mg/yr sometime
after the initial calculation, 3 years is allowed to achieve
compliance and conduct a performance test from the date of the
klk-85\04 1-18
-------
first periodic report documenting NMOC emissions of 50 Mg/yr
or greater.
1.1.10 Method 2E
In Tier 3, the landfill owner or operator may determine
the landfill gas flow rate with Method 2E by installing a
single cluster of three extraction wells or five extraction
wells equally spaced over the landfill. The cluster wells are
preferred, but may be used only if the composition, age of the
solid waste, and the landfill depth of the test area can be
•
determined. The construction of the extraction well is the
same regardless of the pattern, and is specified in the
method.
Pressure probes are located along three radial arms
120 degrees apart at distances of 3, 15, 30, and 45 m from
each extraction well. The probes 15, 30, and 45 m from each
well are called deep probes and extend to a depth equal to the
top of the perforated section of the extraction wells. The
three probes located 3 m from the well are called shallow
probes and extend to half the depth of the deep probes. The
method has been revised to require the pressure probes to be
capped or the probe hole to be refilled with cover material
after testing is complete.
After the wells have been installed and the static flow
rate of the landfill gas from the wells has been measured,
short-term testing is done on each extraction well to
determine: (1) the maximum vacuum that can be applied by a
blower to the wells without infiltration of air into the
landfill and (2) the maximum radius of influence associated
with the maximum blower vacuum.
A leak check is required to ensure accurate flow rate and
safety, using Method 3C. Maximum blower vacuum is determined
by increasing the vacuum and testing for infiltration of air
into the landfill. Method 2E has been changed to specify the
use of a blower with a capacity of at least 8.5m3 per minute.
Infiltration of air into the landfill is considered to have
occurred if any of the following conditions are met: the
kUc-85\04 1-19
-------
temperature of the LF6 at the wellhead is more than 55 OQ or
above the maximum temperature established during the static
testing, the concentration of nitrogen in the LFG exceeds
20 percent, or one of the shallow probes has a negative gauge
pressure. Once infiltration is indicated, the maximum blower
vacuum is determined by reducing the blower vacuum at the
wellhead until the nitrogen concentration is less*than
20 percent, the gauge pressures of the shallow probes are
positive, and the temperature of the landfill gas at the
wellhead is less than 55 °C or below the maximum temperature
established during the static testing.
The temperature check is required to monitor for
subsurface fires and aerobic conditions. If infiltration does
occur, oxygen is brought into the anaerobic environment
beneath the cover. Therefore, the temperature must be
recorded during the static test. This temperature is used to
determine the maximum allowable temperature during the pumping
test. The pumping test temperature should not rise above
55 °c or above the maximum temperature established during the
static testing.
The maximum radius of influence (ROI) is the radial
distance from the extraction well that is affected by the
maximum blower vacuum. This distance is determined by
comparing the initial average pressure for each deep pressure
probe distance for the static portion of the test with the
final average pressures for each distance from the short term
pumping portion of the test. The farthest distance where the
final average pressure is less than the initial average
pressure is the maximum ROI. The maximum ROI may be
determined by plotting the pressure differentials (initial
pressure minus final pressure) versus the natural log of the
distance from the wellhead. Extrapolation is used to
calculate the distance at which the pressure differential is
zero. This distance is the maximum ROI. Method 2E has also
been revised to allow the use of a semi-log plot of pressure
kli-85\04 1-20
-------
differentials versus distance from the wellhead for
determining ROI.
Once the maximum blower vacuum and the maximum radius of
influence have been established, long-term testing begins.
Long-term testing consists of withdrawing landfill gas until
two void volumes have been extracted. A void volume is the
amount of landfill gas in a cylindrical volume defined around
the extraction well with a radius equal to the maximum radius
of influence.
Duri'ng the long-term testing, a stabilized flow rate is
established and used to determine k, the methane generation
rate constant. This site-specific k is used along with the
site-specific landfill NMOC concentration (determined using
Method 25C or Method 18) to recalculate the NMOC mass emission
rate by using equations in Method 2E.
1.1.11 Method 3C
Method 3C is used to determine the nitrogen concentration
in landfill gas samples by injecting a portion of the gas into
a gas chromatograph (GC) and determining the nitrogen
concentration by a thermal conductivity detector (TCD) and
integrator. The concentrations of methane, CC>2, and oxygen
can also be determined using this method.
In Tier 2, when the NMOC concentration in the landfill
gas is determined by Method 25C, Method 3C is used as a check
on the integrity of the sample. Nitrogen is used as a
surrogate for air, and nitrogen concentrations of greater than
20 percent in the sample indicate improper sampling probe
installation or sampling technique, and the sample must be
rej ected.
In Tier 3, when Method 2E is used to determine the flow
rate of landfill gas from the landfill, Method 3C is used to
determine the presence of nitrogen concentrations exceeding
20 percent in a landfill gas sample, which is an indication of
infiltration of air into the landfill.
Method 3C is prescribed for the option of monthly
monitoring of nitrogen concentration for air infiltration.
ktt-85\0* 1-21
-------
(Alternatively, the rule allows monthly monitoring of oxygen
instead of nitrogen.) Method 3C may also be used to leak
check the above ground extraction well apparatus. The
landfill gas is extracted from the landfill by a blower and
the flow rate is measured by a gas flow measurement device.
Leaks in the well piping may affect the flow rate measured by
the device significantly. Therefore, Method 3C is used during
Method 2E testing. The concentration of N2 is measured at the
wellhead sample port and at a point downstream of the flow
rate measuring device, and a difference of greater than
10,000 ppmv indicates a leak. In this case, the owner or
operator must locate and repair the leaks to the system and
repeat the sampling and analysis.
1.1.12 Method 25C
Method 25C is used to determine the concentration of NMOC
in landfill gas. A sampling probe is perforated at one end
and driven or augured to a depth of at least 1 m below the
bottom of the landfill cover. The sample probe depth
requirement in Method 25C has been changed to read "extend no
less than 1 m below the cover" to increase flexibility in
sampling. Additionally, a requirement has been added to both
Methods 25C and 2E to cap or refill the probe holes with cover
material once sampling or pressure testing has taken place.
The owner or operator may choose to leave the probe in place
and simply plug the sampling probe or remove the probe and
refill the hole with cover material.
Landfill gas is extracted from the probe with an
evacuated cylinder at the rate of 500 ml/min
(30.5 ±3.1 in3/min), and the carrier gas bypass valve is used
to pressurize the cylinder with helium to approximately
1,060 mm mercury absolute pressure. The landfill gas will not
condense when it mixes with the dry gas. This approach
provides a method of addressing the small amounts of
condensate without requiring a condensate trap, which would
make the test more expensive and complicated.
klk-85\04 1-22
-------
The NMOC content of the sample gas is determined by
injecting a portion of the gas into a gas chromatographic
column to separate the NMOC from carbon monoxide (CO), CO2,
and methane. The NMOC are then oxidized to C02/ reduced to
methane, and measured by a flame ionization detector (FID).
In this manner, the variable response of the FID associated
•«
with different types of organics is eliminated.
The method for determining the number of samples has
changed from the proposal. Instead of using statistics based
*
on the scatter in the individual measured NMOC concentrations
to determine the required number, the landfill must install a
minimum of two probes per hectare. For landfills greater than
25 hectares, a minimum of 50 probes are required, but the
owner or operator may use more if desired. Additional probes
must be evenly distributed as well (i.e., 3 probes per
hectare), and all of the samples must be used in the analysis.
1.2 SUMMARY OF MAJOR COMMENTS AND RESPONSES ON THE PROPOSED
STANDARDS AND EMISSION GUIDELINES
In the proposal Federal Register notice, the EPA
requested comment on four issues, (1) the use of an
alternative format for the regulatory cutoff, (2) the
inclusion of materials separation requirements in the NSPS and
EG, (3) the establishment of a separate BDT for methane, and
(4) the inclusion of specific energy recovery requirements
within the NSPS and EG. In addition to discussing comments
received on these topics, this section summarizes comments on
the selection and implementation of BDT, and provides the
rationale for changes made to the regulations since proposal.
1.2.1 Response to EPA Solicitation of Comments
1.2.1.1 Alternative Regulatory Cutoff Format. In the
preamble to the proposed regulations, the EPA requested
comment on its decision to use the same format for the removal
of control equipment as was used for the installation of the
control equipment. However, no comments pertaining to the
alternative regulatory cutoff format were received.
klit-85\04 1-23
-------
Therefore, the format for equipment removal has not changed
since proposal.
1.2.1.2 Material Reparation Requirements. Two
commenters supported including material separation
requirements within the proposed rules under Section 111 of
the CAA, while seven favored leaving such requirements to be
decided under RCRA. After considering these comments, the EPA
decided not to include materials separation requirements
within the final rules because the EPA continues to believe
RCRA and 'local regulations are the most appropriate vehicle to
address wide-ranging issues associated with solid waste
management for landfills.
The final RCRA subtitle D preamble identified an array of
initiatives designed to expand recycling efforts (56 FR 50980;
October 9, 1991). Under section II-D of that preamble, "EPA's
Solid Waste Agenda for Action," the EPA explained the current
strategy and stressed three national goals for MSW management.
These goals were: (1) to increase source reduction and
recycling; (2) to increase disposal capacity and improve
secondary materials markets; and (3) to improve the safety of
solid waste management facilities. The EPA strategy was
composed of numerous initiatives, including market studies,
federal recycling procurement guidelines, the development of
training materials for State, local, and Tribal recycling
coordinators, publications, and the establishment of a
national recycling institute.
More recently, the EPA is considering similar initiatives
as part of its effort to encourage recycling through education
and voluntary programs.
1.2.1.3 ft Separate Best Demonstrated Technology for
Methane. Under the proposed regulations, MSW landfill
emissions, or LFG, was selected as the pollutant to be
regulated. Landfill gas is composed of various air pollutants
including CC>2, methane, and NMOC. Nonmethane organic
compounds were specified as a surrogate for MSW landfill
emissions for measurement purposes. The proposed regulations
klk-85\0* 1-24
-------
required that air emissions from new and existing MSW
landfills emitting 150 Mg/yr of NMOC or more be reduced using
a gas collection and control system as part of BOT.
While some commenters to the proposed standards supported
the use of NMOC as a surrogate for MSW landfill emissions,
other commenters considered VOC, total organic carbon (TOC),
and methane to be more appropriate surrogates. Some of these
commenters asserted that methane deserved a separate standard
of its own. Other commenters concurred with the EPA's
•
proposal decision to consider only the ancillary benefits of
methane when setting the standard based on NMOC emission
potential. These commenters asserted that additional
consideration of methane was unwarranted, since significant
methane reductions would occur indirectly from the regulation
of NMOC.
Two commenters wanted a separate methane standard to be
developed to more completely address the health and
environmental effects of methane, including the role of
methane in global warming and the formation of ozone in the
troposphere, and the ability of methane to cause explosions
and transport toxics. Another commenter stated that methane
reductions should be considered directly in the selection of
BDT because of the serious health and welfare effects,
including global climate change impacts, of methane emissions.
One commenter suggested that current and ongoing methane
studies be evaluated to determine whether additional
regulation of methane is warranted. Another commenter said
the regulation should place more emphasis on reducing methane
through such measures as source reduction and recycling,
especially at small facilities.
In setting standards and EG which reflect BDT under
Section 111 of the CAA, the EPA considered reductions of NMOC
directly and methane reductions as an ancillary benefit.
Methane reductions were quantified and considered in selecting
the stringency level of the rule. However, NMOC was selected
as a surrogate for MSW landfill emissions because NMOC
kli-85\04 1-25
-------
contains the landfill air pollutants posing more concern, due
to their adverse health and welfare effects. In addition, the
EPA agrees with the commenters who considered separate methane
controls as unnecessary because reducing NMOC concentrations
in LFG will significantly reduce the amounts of methane
emitted in LFG. Specifically, the methane produced by
existing landfills will be reduced by 39 percent due to the
50 Mg/yr NMOC cutoff.
The U.S. Climate Change Action Plan, released in
October 1993, contains a series of actions to reduce emissions
of methane from landfills and other sources. The Climate
Change Action Plan forms the cornerstone of the U.S. National
Action Plan required by the Framework Convention on Climate
Change, which the U.S. signed in 1992. The EPA actions to
reduce emissions of methane and other greenhouse gases will be
guided by the directives contained in the Action Plan.
Therefore, the EPA maintains that no separate BDT for methane
is needed at this time.
1.2.1.4 Energy Recovery Requirements. Several
commenters wanted energy recovery to be promoted through this
NSPS. Some recommendations for promoting energy recovery
included: discussion in the preamble, relaxed regulations for
sources implementing energy recovery, and economic incentives.
Many commenters also supported the consideration of energy
recovery in the cost-benefit analysis, and some commenters
indicated a site-specific feasibility analysis for energy
recovery should be required by the regulation. However, only
one commenter supported including provisions within these
rules that would require the use of energy recovery devices
for some affected and designated sources. One commenter
suggested that energy recovery technologies also be defined as
BDT, and further suggested that the cost effectiveness
analysis be revised to incorporate the role of energy
recovery.
The EPA decided to incorporate energy recovery in the
nationwide impacts analysis by adding an energy recovery
kli-85\04 1-26
-------
scenario to the original flare analysis upon which the
selection of BDT is based. As mentioned in section 1.3.2.1, a
conservative assumption was made addressing this issue. The
analysis assumes that the 138 most profitable landfills are
the 138 landfills that operate annually in the U.S.
Therefore, these top landfills were removed from the analysis.
Primarily due to this reason, the energy recovery analysis did
not predict any lower costs than did the original methodology
in which all landfills are assumed to use flares.
The'revised nationwide impacts analysis was modified to
select the least-cost of three control options for each model
landfill: the use of flares, I.e. engines, or turbines for
the full control period. In some cases, use of an I.e. engine
or turbine results in a net profit because the energy recovery
profits outweigh the control costs.
Additional cost data were gathered for turbines and
I.C. engines for use in the revised analysis. The sources of
data and costs derived from them are presented in "Changes to
the Municipal Solid Haste Landfills Nationwide Impacts Program
Since Proposal" (Docket No. A-88-09, Item No. IV-M-3). As
discussed in section 1.3.2.1, the EPA performed analysis which
concluded that approximately 138 landfills would recover
energy annually in the absence of the regulation.
After considering these comments and adding an energy
recovery scenario to the analysis, the EPA continues to
believe that the use of energy recovery should be a
site-specific decision. Such a decision should be made after
the landfill owner or operator considers the potential for
income from energy utilization given the uncertainty in the
amount of gas produced. Many other variables come into play
when considering energy recovery, such as gas market
fluctuations, gas production rates, ability to market or
distribute electricity produced, and the quality of the gas.
Not all energy recovery ventures from landfill gas have been
successful in the past. Technical difficulties vary from site
to site and may include such barriers as the gas being unfit
kli-85\04 1-27
-------
for recovery because of non-combustible components or an
insufficient flow rate to maintain dependable operation of
equipment. On the other hand, some landfills may generate
adequate volumes of clean burning gas that would make energy
recovery profitable. For these reasons, the EPA is strongly
encouraging, but not mandating, energy recovery within these
standards.
The EPA's Office of Research and Development has
developed several technology transfer tools to help encourage
energy recovery from landfills, one tool is a software model
and user's manual for estimating landfill air emissions using
the equation and defaults specified in the rule. The Landfill
Air Emissions Estimation Model (version 2.0) and user's manual
can be obtained from NTIS or the EPA Control Technology Center
at the phone numbers listed below. The model also contains
AP-42 emission factors for developing estimates for State
inventories.
Another aid to the regulatory work sponsored by the EPA
is a report entitled, "Landfill Gas Energy Utilization:
Technology Options and Case Studies," EPA-600/R-92-116, June
1992. This report includes detailed case studies of six sites
for the range of every recovery option in use, data on over
50 projects, and information on the capital and operating
costs.
The EPA has also developed a report on the technical and
nontechnical factors to consider including a discussion of
different philosophies of major operators of landfill gas
recovery projects regarding gas cleanup and operation. The
report is entitled "Landfill Gas Energy Utilization
Experience: Discussion of Technical and Nontechnical Issues,
Solutions and Trends", EPA-600/R-95-035. Two other reports
developed by the EPA's Office of Research and Development in
1995 are: "Emerging Technologies for Landfill Gas
Utilization" and "Methodologies for Quantifying Pollution
Prevention Benefits from Landfill Gas Control and
Utilization". These documents and the ones discussed above
klk-85\OA 1-28
-------
are available through the National Technical Information
System at (703) 487-4650 (phone) or (703) 321-8547 (fax) or
the EPA Control Technology Center Hotline at (919) 541-0800
(phone) or (919) 541-2157 (fax). Technical assistance
regarding the CAA regulation, estimating landfill emissions,
and evaluating control and landfill gas utilization options
can also be obtained by calling the Control Technology Center.
The EPA has also developed a Landfill Methane Outreach
Program to assist owners and operators interested in landfill
gas energy recovery and to encourage more widespread
utilization of landfill gas as an energy source. Information
regarding the Program can be obtained by calling the Landfill
Methane Outreach Program Hotline at (202) 233-9042.
1.2.2 Rationale for Significant Chances to Regulation
1.2.2.1 Selection of Design Capacity Exemption Level.
The proposed rule included a design capacity exemption to
reduce the burden on small landfills. Several commenters
discussed the proposed design capacity exemption level of
100,000 Mg. Several comments were submitted requesting an
increase in the exemption level. An increase would relieve
additional owners and operators of small landfills from the
emission estimation and control requirements. Two commenters
recommended a specific higher exemption level. One of the
commenters contended that no additional MSW landfills having
design capacities less than 100,000 Mg will be built and
recommended an exemption level of 1.0 million Mg. The second
commenter suggested an exemption level of 550,000 Mg, noting
that landfills smaller than this would not emit more than
150 Mg/yr NMOC, and arguing that the lower exemption level
unnecessarily increased the regulatory burden of the standard.
In addition, representatives of state and local governmental
agencies who were consulted under Executive Order 12875
recommended higher exemption levels to relieve small entities
of regulatory burden.
klk-85\04 1-29
-------
One industry conunenter approved of the design capacity
exemption of 100,000 Mg, but also noted that there would still
remain considerable burden for small landfills that would be
exempted at Tier 1. However, the commenter, along with two
other commenters, recommended that all MSW landfills be
evaluated for NMOC emission rates, not only those above the
design capacity exemption level.
The design capacity cutoff of 100,000 Mg of waste was
chosen at proposal so that no landfill would be exempted by
•
size and have actual emissions above the emission rate cutoff.
In addition to the comments, changes to the data base and the
emission modeling values prompted a reevaluation of the design
capacity exemption level.
The new design capacity exemption analysis evaluated a
range of options from 500,000 Mg to 4.0 million Mg of waste.
Two important considerations in the selection are the number
of landfills exempted and the amount of potential NMOC
emission reduction lost from the exempted landfills.
The 2.5 million Mg exemption level would exempt 90 percent of
the existing landfills while losing only 15 percent of the
total NMOC emission reduction. Therefore, 2.5 million Mg was
chosen since losing 15 percent of the potential emission
reduction is a reasonable tradeoff to relieve as many small
businesses and municipalities as possible from the regulatory
requirements, while still maintaining significant emission
reduction. The lowest value considered, 500,000 Mg, only
allows slightly more than 1 percent of the total emission
reduction potential to go unregulated; however, only
62 percent of the landfills are exempted so the regulatory
burden is higher than under the chosen option. Exemption
levels higher than 2.5 million Mg resulted in less emission
reduction.
The 2.5 million Mg design capacity exemption level
excludes those landfills, both public and private, who would
be least able to afford the costs of landfill gas collection
kli-85\04 1-30
-------
and control systems. Also, smaller landfills are less likely
to have successful energy recovery projects.
Since some landfills record waste by volume and have
their design capacities calculated in volume, the EPA also
established an equivalent design capacity exemption of
2.5 million cubic meters of waste. The density of landfilled
solid waste varies from landfill to landfill depending on
several factors, including the compaction practices. Any
landfill that reports waste by volume and wishes to establish
a mass design capacity must document the basis for their
density calculation.
1.2.2.2 Selection of the Regulatory Stringency Level.
Several commenters requested a more stringent emission rate
cutoff, while others favored the 150 Mg/yr rate proposed, and
some favored a less stringent standard. One of the commenters
asserted that the NMOC data provided by the EPA at proposal
supports a more stringent level. Other commenters stated that
adding the benefits of energy recovery and abatement of global
warming to the economic analysis would support a more
stringent standard. Two commenters supported a cutoff level
of 25 Mg/yr because of the additional methane reductions that
would result. Another commenter favored a more stringent
standard because the commenter believed that health risks
posed by landfills between a cutoff of 25 Mg/yr and 150 Mg/yr
may be significant.
One commenter supported an emission rate cutoff of
250 megagrams per year. This commenter stated that the BID
and regulatory impact analysis (RIA) for the proposal did not
provide a clear rationale or cost effectiveness for the
selection of a 150 Mg/yr cutoff and that actual health and
environmental benefits are uncertain.
The Climate Change Action Plan, signed by the President
in October, 1993, calls for EPA to promulgate a "tough"
landfill gas rule as soon as possible. This initiative also
supports a more stringent emission rate cutoff that will
achieve greater emission reduction.
ktt-85\0* 1-31
-------
Due to the small-size exemption, only landfills with
design capacities greater than 2.5 million Mg of waste or
2.5 million cubic meters of waste will be affected by this
rule. It is estimated that a landfill of 2.5 million Mg
design capacity corresponds to cities greater than 100,000
people. On the whole, large landfills service areas with
large population. A reasonable assumption is that many of
these large landfills are in the 400 counties that have been
designated as urban ozone nonattainment areas and are
developing plans to address ozone nonattainment.
Finally, the new data and modeling methodologies, which
were published in the notice of data availability on June 21,
1993, significantly reduced the estimated emission reduction
and corresponding effectiveness of the rule. Therefore, a
more stringent emission rate cutoff would achieve similar
emission reductions at similar cost effectiveness to the
proposed rule.
Based on all of these reasons, the EPA reevaluated the
stringency level and chose an emission rate cutoff of 50 Mg/yr
of NMOC for the final rules. This revision would affect more
landfills than the proposal value of 150 Mg/yr of NMOC;
however, the 50 Mg/yr of NMOC will only affect less than
5 percent of all landfills and is estimated to reduce NMOC
emissions by approximately 53 percent and methane emissions by
39 percent. The 150 Mg/yr emission rate cutoff would have
reduced NMOC emissions by 45 percent and methane emissions by
24 percent. The incremental cost effectiveness of control of
going from a 150 Mg/yr cutoff level to a 50 Mg/yr cutoff level
is $2,900/Mg NMOC reduction for new landfills and $3,300/Mg
for existing landfills.
The values for NMOC cost effectiveness do not include any
credit for the benefits for toxics, odor, explosion control,
or the indirect benefit of methane control. A revised cost
effectiveness could be calculated with an assumed credit value
for one or more of the other benefits. As an example,
assuming a $20/Mg credit for the methane emission reduction,
klk-85\04 1-32
-------
the incremental cost effectiveness from the proposal cutoff of
150 Mg/yr to the final cutoff of 50 Mg/yr would be reduced to
$l,300/Mg NMOC.
1.2.2.3 Gas Collection System Design Specifications.
Many commenters wanted the proposed standards to allow more
design flexibility, some wanted the EPA to encourage States to
allow alternative designs and some commenters requested that
the designs be required to be site-specific.
Some commenters noted that the design specifications in
chapter 9 of the proposal BID were too rigid, while one
commenter suggested that to foster development of new designs,
the design specifications in § 60.758 of the proposed NSPS be
removed from the regulation and used only as guidance rather
than as required design specifications. Some commenters
stated that the collection and control design criteria were
based on unproven and invalid theories and models, resulting
in over designed systems.
Other commenters recommended that the regulations
designate an alternative collection system design based on the
South Coast Air Quality Management District (SCAQMD) rule,
which uses integrated surface sampling of total organic carbon
(TOC) to determine if additional gas control is needed. One
commenter noted that such surface sampling encourages system
maintenance.
The design specifications proposed in § 60.758 were
included in the proposed rule to provide a straightforward
basis for system design. However, because of the many site-
specific factors involved in landfill design, alternative
systems may be necessary. To provide design flexibility, the
final regulations no longer contain specific designs, but
require all designs to be prepared by a professional engineer
and submitted to the permitting authority for approval. All
designs must satisfy the criteria for an effective collection
system provided in S 60.759. The removal of specific gas
collection system design plans from the rules will encourage
technological innovation by allowing sources to design their
klk-85\04 1-33
-------
own gas collection systems to meet specific needs. The
enabling document will contain the specific design information
removed from the regulation, so that if landfills wish to use
the design specifications, they will be available.
1.2.2.4 Operational Standards for Collection and Control
Systems. Several commenters identified a variety of
operational considerations that may affect the installation
and operation of collection and control systems, and they
suggested that these considerations should be addressed by the
•
standards. Some of these considerations related to the
landfill environment, such as: settlement or movement of
landfill or cover surfaces; changing topography, weather, and
barometric pressure; presence of on-site structures; gas
generation rate; and existing passive venting systems. Other
considerations focused on management practices or operation of
the collection and control system, such as: equipment
traffic; the effect of bailing waste; equipment leaks;
maintenance and repair practices; treatment of leachate and/or
condensate; provisions for flame-outs, downtime, malfunctions
or pipe leaks; air injection; and the effects of sampling
ports.
The EPA agrees that these considerations will have an
effect on the installation and operation of collection and
control systems. All of these considerations, however, vary
from site to site, and the EPA judged that, in general, most
of these concerns are best addressed by the local operator.
The treatment of leachate and condensate is already addressed
under RCRA (subtitle D).
The operational specifications provided in the proposal
are not intended to replace the operator's knowledge of, and
response to, the situations discussed above. However, well-
operated and we11-maintained equipment should be used to
comply with these rules, which should keep air emissions
through leaks in equipment at a minimum.
In addition to the removal of the prescriptive design
criteria for gas collection systems, the EPA made several
kli-85\0* 1-34
-------
logical changes to the proposed rules on issues raised by
commenters. Two of these changes are significant. The first
change was to aggregate the various operational provisions
that had been located at different points throughout the
proposed regulation in a new § 60.753, "Operational standards
for collection and control systems." Second, as^suggested in
the proposal preamble, to ensure that the integrity of the
landfill cover is adequately maintained, a requirement to
operate the collection system so that surface methane
concentration is less than 500 ppm has also been included.
In summary, new § 60.753 addresses the following areas:
(1) collection of gas from active areas containing solid waste
older than 5 years, and 2 years for areas closed or at final
grade; (2) operation of the collection system with negative
pressure at each wellhead (with exceptions added since
proposal); (3) operation of the collection system with a
landfill temperature less than 55 °C (or a higher established
temperature) and either a nitrogen level less than or equal to
20 percent or an oxygen level less than or equal to 5 percent;
(4) operation of the collection system with a surface methane
concentration less than 500 ppm; (5) venting all collected
gases to a treatment or control device; and (6) operation of
the treatment or control device at all times when the
collected gas is routed to the control device.
The requirement to collect gas from areas containing
solid waste was changed from 2 years at proposal for all
areas, to 5 years for active areas and 2 years for closed or
final grade areas. A summary of comments on this requirement
and rationale for the change is contained in section 1.2.2.7
on "System Expansion."
The proposed requirement to maintain negative pressure at
wellheads was not changed. The EPA has, however, provided for
three exceptions when it may not be possible for sources to
maintain negative pressure at wellheads. These exceptions are
also discussed in section 1.2.2.7.
klk-85\04 1-35
-------
The proposed requirement for operation of the collection
system with nitrogen levels less than or equal to 1 percent
was revised to 20 percent based on new information received
since proposal. An alternative provision for maintaining an
oxygen level less than or equal to 5 percent, and an
additional provision maintaining a temperature of less than
55 °C (or a higher established temperature) were added. The
rationale for these changes is provided in section 1.2.2.6 on
"Monitoring of Operations."
A significant new requirement to operate the gas
collection system with a surface methane concentration less
than 500 ppm (along with monitoring provisions to ensure
maintenance of this concentration) was added after proposal.
This surface emission limit was included under the operational
standards, because the EPA is using it to verify that the
system is adequately operated and maintained and not to ensure
an emission limit, surface or otherwise, as normally
constructed under Section 111. The rationale for this
requirement is also provided in section 1.2.2.6.
The requirements to vent all emissions to a treatment or
control device and to operate the device at all times when the
emissions are being routed to the device have not changed
since proposal. Provisions for downtime and malfunction are
described in section 1.2.2.5.
In conjunction with the new operational provisions, the
compliance, testing, and monitoring sections were revised to
reference and support these new or relocated provisions.
1.2.2.5 Start—up. Shutdown, and Malfunction Provisions.
In response to the comments regarding system start-up,
shutdown, and malfunction, the EPA has added provisions in
S 60.755 of the final NSPS as follows:
"(e) The provisions of this subpart apply at all
times, except during periods of start-up, shutdown,
or malfunction, provided that the duration of
start-up, shutdown, or malfunction shall not exceed
5 days for collection systems, and 1 hour for
treatment or control devices."
klk-B5\0* 1-36
-------
When considering the various provisions for start-up,
shutdown or malfunction conditions recommended by the
commenters, the EPA has chosen to include provisions that are
linked to compliance for ease of implementation.
The 5-day exemption period for collection systems was
selected in recognition that a major problem with*a collection
system will likely take some time to locate and solve but also
that the landfill is not going to stop generating LFG. In the
design and operational standards of these rules, compliance
with the standards is meeting the requirements for the
installation and operation of a properly-designed system. The
EPA recognizes that a shut down system cannot possibly meet a
standard requiring that a collection system be actively
collecting LFG. In recognition that flame-outs and problems
with the collection system do occur, the EPA did not want to
render owners and operators of well-designed and operated
systems out of compliance with the standards under normal
operating circumstances. Therefore, a reasonable exception to
the compliance provisions was sought.
The EPA has decided to include a 1-hour repair window for
control devices within the final NSPS and EG. The 1-hour
period was selected for control devices because, in practice,
most sites currently collecting landfill gas have multiple
control devices, whether multiple flares, boilers, I.e.
engines, turbines, fuel cells, or combinations of the above.
Therefore, only a short period of time would be necessary to
relight a flare or reroute the collected gas to an alternative
device.
While all periods when collection or control equipment
are not operating must be recorded, only periods in excess of
5 days for collection systems and 1 hour for control devices
must be reported in the annual excess emission report. And,
as required in § 60.11(d), the collection and control system
must be maintained and operated at all times, including
periods of start-up, shutdown or malfunction, in a manner
klk-83\0* 1-37
-------
consistent with good air pollution control practice for
minimizing emissions.
Localized problems with crushed pipes, etc., may be
resolved through adjustments to the draw from other wells in
the vicinity until repair is effected. If the blowers need to
be repaired or replaced, the collection/control system may be
able to function temporarily as a passive system while repairs
are effected. However, the EPA has no data upon which to base
how long .such an arrangement would be feasible. Therefore,
owners and operators should take care to plan for such
contingencies. Whether the owner or operator has arranged
with vendors for quick turnaround on replacement parts, has
spare system components on site, or has multiple devices on
line so that the flow may be distributed among them,
compliance can be maintained in a number of ways. Therefore,
the EPA has elected to specify a downtime that is acceptable
under these rules, and leave the actual repair strategy to the
owners and operators.
1.2.2.6 Monitoring of Operations.
Control Device Monitoring—Two commenters questioned how
the residence time during the initial performance test of a
flare could be monitored and suggested perhaps the
requirements intended to require calculation of the residence
time. One of the commenters also suggested a monitoring
schedule be added.
The monitoring provisions of the MSW landfill NSPS are
based on typical Section 111 provisions for open flares and
enclosed combustion devices. New provisions allow sources to
monitor the use of bypass systems using car seal or lock and
key type configurations instead of monitoring flow to the
control device. These provisions were added to reduce the
burden imposed by monitoring requirements.
The intent of this section of the regulation is to
require that residence time be determined during the initial
performance test for enclosed combustors. Flares are open
combustors which have no "residence time" associated with the
kli-85\0* 1-38
-------
combustion. The final regulation was changed to reflect that
residence time should be determined in conjunction with gas
flow measurements rather than "monitored." After the initial
performance test, the NSPS only requires that temperature and
flow (or bypass) be recorded with equipment calibrated,
maintained, and operated according to the manufacturer's
specification.
Two commenters recommended that the flare flame, rather
than the pilot flame, be monitored to verify that the flare is
operating at all times. The monitoring provisions have been
changed to allow monitoring of either the pilot flame or the
flare flame itself to determine if the flare is operating.
Pilot flare monitoring is allowed because the temperature of
the flare flame is high and may cause the thermocouple to burn
out more quickly. The requirement to monitor flow to the
flare or other control device every 15 minutes, or to prevent
bypass of the control device using a car seal or lock and key
type system, is to ensure that the collected landfill gas is
being conveyed to a flare or other suitable control device
rather than being discharged to the atmosphere.
Surface Monitoring—Some commenters recommended that the
regulations incorporate an alternative collection system
design provision, which would establish a performance standard
based on the SCAQMD rule. The SCAQMD rule uses integrated
surface sampling of TOC to determine the need for additional
gas control. This would allow more flexibility for the gas
collection designs. One commenter noted that their State
regulation requires that gas collection systems be designed so
that surface concentrations of methane do not occur above
certain levels. The commenter asserted that a surface test
encourages system maintenance. Commenters also asserted that
a surface emission standard which landfill operators must
maintain would allow maximum design flexibility and
encouraging more cost effective innovations.
One commenter was concerned about the integrity of the
landfill cover and that cracks in the cover could allow
klk-85\04 1-39
-------
emissions to the atmosphere even when an effective collection
system has been installed. As mentioned in the proposal
preamble, surface emission monitoring as used in the SCAQMD
seems appropriate for determining that closer well spacing is
in fact needed. As mentioned in the proposal preamble, the
EPA was already considering what role the California test
might reasonably fill in these regulations (see
56 FR 24492-24493).
The EPA considers surface emission monitoring to be an
appropriate tool for monitoring both cover integrity and the
effectiveness of well spacing. Therefore, some aspects of the
surface emission monitoring test have been incorporated in the
new S 60.753, where all of the operational provisions for the
collection system have been brought together.
After initial installation of the collection system,
owners and operators will be required to operate the
collection system with a methane concentration less than
500 ppm at all points around the perimeter of the collection
area and along a serpentine pattern across the entire surface
of the landfill. Compliance with this operational standard is
to be demonstrated by monitoring surface concentrations on a
quarterly basis using an organic vapor analyzer, flame
ionization detector, or other portable hydrocarbon monitor.
If an instrument reading of 500 ppm or greater is produced,
the location of the exceedance must be recorded, and cover
maintenance or adjustment to the vacuum at adjacent wellheads
must be made within 10 calendar days. The 10-day schedule was
selected to allow the personnel to continue monitoring without
stopping to make adjustments, but to assure that conditions at
the locale of the exceedance are attended to quickly.
A second measurement must be taken within 10 days. If a
second exceedance is recorded at the same location, additional
adjustments shall be attempted and additional monitoring
performed within 10 days. If a third exceedance is recorded
at that location, an additional well must be installed within
120 days of the first exceedance.
kli-B5\0* 1—40
-------
The methane concentration level of 500 ppm was chosen
based on data received from numerous sources, including:
(1) information provided by the SCAQMD stating that this was
an appropriate level and the level used at landfills in that
district; (2) information indicating that some leak detection
programs for other industries currently use 500 pj?m and
analyzers are capable of detecting this level;
(3) instrumentation specifications citing this as an
appropriate number and that familiarity with this level is
broad; and (4) site visits conducted by the EPA indicating
that 500 ppm is an acceptable detection level.
Surface monitoring will provide a safeguard against
uncertainties in well density determination, no matter what
collection method is used. The new surface monitoring
provisions include requirements for increased monitoring and
corrective actions upon exceedance of 500 ppm.
Nitrogen Monitoring—Many commenters stated that the
1 percent nitrogen limit in the proposed standard for
infiltration detection was unrealistic and reported typical
levels of 5 to 11 percent. Some commenters stated that
nitrogen measurements are expensive and that other methods,
such as well temperature or percent methane should be allowed
as indicators of excess air infiltration.
In Method 2E as well as daily operation, the nitrogen
concentration in the extracted LFG is important because it
indicates if the maximum vacuum achievable without air
infiltration is being obtained from the landfill. The EPA set
the nitrogen limit as a safety measure to avoid fires and
explosions that may result from pulling too much air into the
landfill and to avoid altering the anaerobic state of the
landfill. For compliance purposes, the main concern is that
the system is pulling at maximum capacity up to the point of
infiltration.
The monitoring provisions of the final NSPS have been
revised after consideration of the comments. The nitrogen
limit during operation of the collection system at the
kUt-85\0* 1-41
-------
wellhead has been increased to 20 percent based on the
evaluation of numerous comments on this subject.
The nitrogen limit in Methods 2E and 25C has also been
increased to 20 percent. In Method 2E, a sample found to
contain more than 20 percent nitrogen indicates infiltration.
If a sample is found to contain more than 20 percent nitrogen
in Method 25C, then that sample should be removed from the
collection. The equation for calculating the NMOC
concentration in Method 25C has also been revised to correct
the NMOC concentration in the LFG sample to zero percent
nitrogen.
Because commenters indicated that nitrogen measurement
via Method 3C is impractical, provisions have also been added
that allow for the monitoring of oxygen using Method 3A. The
measurement of oxygen via portable monitoring devices is
already being done in the field, and an oxygen threshold of
5 percent would correlate to an nitrogen value of 20 percent.
Temperature Monitoring—A provision requiring the
temperature to be maintained below a set limit has also been
added. This temperature limit is 55 °C, or a higher
temperature at each well that the owner or operator can
document will not cause fires or inhibit anaerobic
decomposition. If the LFG temperature at the wellhead
increases above the temperature threshold, the new provisions
require an adjustment of the vacuum to reduce the temperature.
The value of 55 °C was cited by industry experts as an alert
temperature that may indicate a problem. Since temperature
variability exists between landfills and between wells within
a landfill, the provision to establish higher operating
temperatures at individual wells has been added. A higher
temperature limit will be allowed, however, only if the owner
or operator can demonstrate with supporting data that the
higher temperature does not cause fires or adversely affect
the anaerobic decomposition of the waste.
As with nitrogen monitoring, an alternative method for
measuring temperature may be used if it is documented and
kli-85\0* 1-42
-------
maintained with the landfill records. The EPA realizes many
owner or operators presently extracting gas use other
compounds, conditions, and theoretical ratios to monitor for
air infiltration. Therefore, this flexibility allows them to
use these methods for demonstrating compliance with the
regulation.
1.2.2.7 System Expansion. Commenters expressed two
primary concerns dealing with system expansion. The first
concern centered around the requirement to expand extraction
systems into each area after 2 years of waste deposition.
Some commenters suggested that such a timeframe is
unreasonable and does not coincide with common operation
practices. Commenters suggested that other means, such as
emission potential, be used to determine when wells should be
placed rather than a time requirement or site-specific data.
The second concern was the requirement to install an
additional well in the vicinity of a well where negative
pressure cannot be achieved through valve adjustment at the
wellhead. Commenters indicated the provisions were vague and
that a time schedule should be added to the provisions.
The EPA has reanalyzed the provisions of these rules in
response to public comment regarding both maintenance of
negative pressure at the wellhead and the addition or
replacement of wells. These changes to the rule were placed
in § 60.753, "Operational Standards for Collection and Control
Systems," and S 60.755, "Compliance Provisions."
The provision requiring maintenance of negative pressure
at wellheads has not been changed. However, exceptions to
negative pressure at wellheads have been added to the rules.
The exceptions are as follows: (1) If there is a significant
increase in temperature (or fire), in which case the source
may need to reduce the vacuum or go to positive pressure. If
this occurs, the owner or operator must record and report the
event; (2) If the source is using a synthetic cover or
geomembrane. In this case the owner or operator must
establish the maximum positive pressure allowable in the
klk-85\04 1-43
-------
design plan and have it approved. If this is not in the
original design plan, the plan must be updated to include
positive pressure limits; and (3) In an area of declining gas
flow, wells that are shut off to allow higher flows at
adjacent wells may experience static positive pressure. The
owner or operator must update the design plan and^have it
approved before shutting off wells in declining areas.
After initial installation of the collection system,
owners and operators will be expanding the collection system
over time to provide adequate coverage for all active areas in
which waste has been deposited for 5 years. The 5 year period
is believed to be more re -sonable and consistent with common
landfill practices than the proposed 2-year period for active
areas of the landfill. A given area is typically active for
more than 2 years. If collection system wells are required to
be installed within 2 years, they will likely get covered
over, decreasing their operational life. This scenario would
increase costs and be inefficient. Thus, a 5-year period is
allowed. A period longer than 5 years is not allowed because
emissions from a given block of waste will decline over time,
so it is important to install collection and control systems
as soon as reasonably practical. For areas that are closed or
at final grade, collection system wells must be installed
within 2 years.
There are also two cases in which wells must be added
unexpectedly—when negative pressure cannot be achieved at a
given wellhead within a 15 days (except as noted in the three
exceptions above) and when surface methane levels cannot be
reduced below 500 ppm after three attempts in 30 days.
In the first case, 15 days are allowed to restore
negative pressure at the wellhead and thereby avoid
installation of an additional well. The principal reason
positive pressure is likely to occur is that the collection
system capacity in the locale of the well is less than the
production in the area. Either collection capacity can be
klk-85\0* 1-44
-------
increased through adjustments to the vacuum, or system
expansion is warranted.
The 15 days allows time for a surge in generation after
significant rainfall to subside or for the operator to make
all attempts to restore negative pressure through other means.
Any operational adjustments the operator can make to restore
the well to proper function within this timeframe* are not
precluded by these rules. If negative pressure cannot be
restored within this 15-day period, however, the area is
producing more gas than the wells in that area are able to
handle, and the installation of an additional well is
warranted. If rainfall results in increased generation on a
regular basis, an additional well is also warranted to
accommodate this regular increase in gas production.
In the case when methane concentrations are monitored at
500 ppm or more, two 10-day periods are allowed after initial
measurement to reduce surface methane concentrations below
500 ppm. There are two reasons likely to contribute to
excessive methane levels—cover failure or insufficient
density of wells. When excessive methane concentrations are
recorded, 10 days are allowed for personnel to evaluate the
problem. If the cover has been disturbed, maintenance will
likely reduce surface levels. On the other hand, if the
density is insufficient for the gas production level in the
vicinity, adjustment of the vacuum may extend the effective
area and methane concentrations also decrease. An increase in
vacuum cannot always be used, however, because there is a
trade-off in increasing the vacuum and avoiding excessive air
infiltration. Therefore, if the vacuum is increased as much
as possible without excessive infiltration and the surface
methane concentrations still reach or exceed 500 ppm,
installation of an additional well is warranted.
Because disturbance of the cover can coincide with an
ineffective area of influence, the EPA has allowed an
additional 10 days after a subsequent exceedance. It is
expected that methane concentrations will usually subside
klk-85\04 1-45
-------
after cover maintenance or vacuum adjustments are made. The
EPA believes, however, it would be possible for landfill
personnel to locate and repair cracks or other flaws in the
landfill cover, thinking that the repairs would address
excessive methane levels that result, at least in part, from
an ineffective area of influence. However, if the area is
highly productive, excessive methane concentrations might
still be monitored in the subsequent 10-day period in spite of
the repairs to the cover. In this case, an adjustment to the
vacuum at* adjacent wells may still restore surface methane
concentrations to acceptable levels, even though a second
exceedance was recorded. Rather than requiring that owners
and operators remonitor at the location of every exceedance,
the EPA elected to require remonitoring only when the initial
attempt to reduce surface concentrations has been
unsuccessful. Therefore, varying durations are allowed to
attempt to reduce surface methane concentration to below
500 ppm before the installation of an additional well would be
required.
In both cases of unscheduled system expansion, 120 days
after initial exceedance are allowed for the installation of
the required well. The 60 days beyond that allowed for
scheduled expansion is reasonable because the availability of
materials, drilling rigs or contract personnel for an
unscheduled installation, although anticipated in a general
sense, make the installation of these wells in the 60 day time
period less feasible.
1.2.2.8 Revision of Tier Defaults. Several commenters
challenged the default values for NMOC concentration, C^oo
methane generation rate constant, k, and methane generation
potential, Lo. Most of the commenters argued that the values
used were overly conservative and that inadequate technical
justification was provided for the values used.
The EPA believes some of the commenters may have been
confused by the nationwide impacts modeling. The values
chosen for the tier defaults were not used to model nationwide
klk-85\0* 1-46
-------
emissions. A more sophisticated analysis was used in the
modeling to select the standard involving ranges of values.
The tier default values were chosen after the nationwide
modeling was complete.
As explained in the preamble to the proposal, the
selection of the default values provided in the tier
•»
calculation was not based on test data alone (56 FR 24489;
May 30, 1991). Rather, the default values were selected after
development of the nationwide impacts analysis to obtain a
balance between lost emission reduction potential and cost of
performing the field tests in Tiers 2 and 3 on a nationwide
basis, as described in the memorandum entitled "Documentation
of Small Size Exemption Cutoff Level and Tier 1 Default Values
(Revised)" (Docket No. A-88-09, Item No. IV-B-6). Lost
emission reduction potential is the loss of emission reduction
due to exempting landfills through the tier calculations when
the landfills are actually greater than the emission rate
cutoff. The values for k, Lo, and C^QC are within an
accepted range and were selected to minimize those landfills
that actually emit more than 50 Mg/yr of NMOC but could
calculate emissions below the cutoff using the defaults. The
three defaults comprise a combination that best achieved the
balance between lost emission reductions and the cost of site-
specific testing to replace the default CJJHOC and * values in
the tier system.
The new default values of 0.05/year for k, 170 m3/Mg for
Lo, and 4,000 ppmv for CJJMOC are for use *n tne Tier analysis.
The memorandum "Methodology for Revising the Model Inputs in
the Municipal Solid Waste Landfills Input Data Bases
(Revised)" (Docket No. A-88-09, Item No. IV-M-4) discusses the
approach used to reevaluate and select these default values.
1.2.2.9 Revision of Method 25C
Method 25C—A few commenters stated that Method 25C needs
to take the gas condensate into account. Method 25C was
revised to include evacuation before and pressurization
afterwards with helium. The landfill gas will not condense
klk-85\0* 1-47
-------
when it mixes with the dry gas. This approach provides a
method of addressing the small amounts of condensate without
requiring a condensate trap, which would make the test more
expensive and complicated.
Implementation of Method 25C—Tier 2 requires performing
Method 25C at a number of surface locations to determine a
site-specific landfill gas concentration. Many commenters
stated that the statistical approach to calculate the number
of samples and the confidence level is not supportable.
Others stated that thorough sampling across the whole surface
would give a better average due to the extreme variability in
waste composition.
In an effort to simplify the Tier 2 process and address
many of the comments, the number and location of Method 25C
sampling probes were revised. Each landfill will take two
samples per hectare of surface area up to 50 samples.
Therefore, any landfill greater than 25 hectares may take a
minimum of 50 samples. Since the confidence level calculation
was abandoned, only one time period is needed for
recalculation of the gas concentration. An active landfill
that calculates the annual emission rate to be below 50 Mg
NMOC/yr in Tier 2 will need to retest the gas concentration
every 5 years.
1.3 SUMMARY OF IMPACTS OF PROMULGATED ACTION AND ALTERNATIVES
Environmental, energy, and economic impacts of NSPS or EG
are normally expressed as incremental differences between
facilities complying with the final standards or guidelines
and those same facilities if no NSPS or guidelines were in
effect. At present, very few State or Tribal agencies have
landfill regulations that address complete landfill gas
control, and few new or existing landfills would be affected
by these State, local, or Tribal regulations.
For most NSPS and EG, emission reductions and costs are
expressed in annual terms. In the case of the NSPS and
guidelines for landfills, the final regulations require
controls at a given landfill only after the increasing NMOC
klk-83\0* 1-48
-------
emission rate reaches the level of the regulatory cutoff. The
controls are applied when the emissions exceed the threshold,
and they must remain in place until the emissions drop below
the cutoff. However, this process could take as long as 50 to
100 years for some landfills. During the control period,
costs and emission reductions will vary from year to year.
Therefore, the annualized numbers for any impact will change
from year to year.
Because of the variability of emission reductions and
costs of the final standards and guidelines over time, the EPA
judged that the net present value (NPV) of an impact is a more
valuable tool in the decision process for landfills and has
used NPV in the development of both the proposal and final
nationwide impacts. The NPV is computed by discounting the
capital and operating costs and emission reductions that will
be incurred throughout the control periods to arrive at a
measure of their current value. In this way, the NPV accounts
for the unique emission patterns of landfills when evaluating
nationwide costs and benefits over different discrete time
periods for individual sources. Thus, the impacts presented
include both fifth year annualized estimates and estimates
expressed in terms of NPV in 1992.
1.3.1 Revisions to the Data Base
During the period between proposal and promulgation, all
the data bases of landfills and modeling values used to
estimate emissions were reevaluated in response to public
comments. After review of the data bases, the following
aspects of the modeling were revised as discussed below: (l)
scale factors; (2) NMOC concentrations; and (3) methane
generation rate constant (k) and methane generation potential
(L0) pairs.
The Office of Solid Waste (OSW) data base used at
proposal included 931 landfills that were identified as either
small or large landfills by a scale factor assignment. The
OSW defined small landfills as those landfills accepting less
than 500 tons/day of waste, while large landfills are those
klk-85\04 1-49
-------
landfills accepting 500 tons/day or more of waste. A scale
factor was applied to each landfill in the data base, which
resulted in a scaled-up total number of landfills to reflect
the true population. The scale factor assignments were later
reviewed to ensure consistency with the OSW criteria for small
and large landfills. Based on the OSW tons/day criteria, some
scale factor assignments were then revised and the primary
scale factors for large and small landfills were adjusted to
yield the corrected number and proportion of small and large
landfills. These adjustments result in a lower annual waste
acceptance rate than the proposal level. This in turn results
in a somewhat lower NMOC baseline emission rate. Compared to
the nationwide impacts analysis at proposal, fewer landfills
would be expected to emit above any given stringency level as
a result of this change in scale factor.
The values for CHMQC used for the proposal, which are
used as an input parameter in the model, were also reviewed
and revised in response to public comment. The new data base
values result in a lower average NMOC concentration than was
reflected in the proposal nationwide impacts analysis.
The values for k and Lo were also reviewed and
regenerated. The result of the recalculation of k, Lo pairs
was a lower estimated overall landfill gas flow rate on a
nationwide basis.
The reanalysis consisted of a closer look at each value
previously included in the nationwide impacts analysis as well
as the inclusion of additional values obtained from ongoing
studies. The notice of data availability placed in the
Federal Register (58 FR 33790; June 21, 1993) outlined the new
data and reanalysis occurring between proposal and
promulgation.
In the reanalysis, for data to be used to obtain k
values, the following had to be available: test year, year
landfill opened, year landfill closed (if closed), amount of
solid waste "in-place" in the test year, solid waste
acceptance rate, and the actual methane flow rate. For data
klk-85\0* 1-50
-------
to be used to obtain NMOC concentrations, the following had to
be available: the total NMOC concentration and associated
units (e.g., ppmv as hexane, ppmv as methane), the methane and
C(>2 concentration (to correct for air infiltration since
landfill gas is primarily methane and CO2)/ and the test
method used. Also, the test method had to be comparable to
the EPA Method 25C.
As a result of these revisions to flow rate and
concentration, both the MSW landfill emissions and NMOC
emissions are less than earlier estimates. Therefore, the
NMOC and methane baseline emissions are lower, and it is
estimated that control would be required at fewer landfills at
any given stringency level, in comparison with the proposal.
1.3.2 Revisions to the Modeling Methodology
Considering public comment, the EPA revised the methods
for assessing nationwide impacts. Some landfills presently
choose to employ energy recovery systems independent of any
regulatory requirements because energy recovery is a
profitable operation. These profitable landfills are removed
from the cost analysis because the cost analysis evaluates the
potential impact of regulatory requirements on landfills that
have not yet chosen to install recovery systems. The EPA also
added a least cost modeling scenario to supplement the
proposal costing methodology. The least cost scenario
estimates impacts if all landfills used energy recovery
whenever the situation was economically more attractive than
simply flaring the gas.
1.3.2.1 Profitable Landfills. As reflected in the
proposal BID and preamble, and stated by some commenters,
there are market impediments that discourage landfill systems
developers from taking a risk on energy recovery systems even
though the standard would provide additional incentive to
install energy recovery systems by requiring landfill gas to
be controlled. In contrast, there is also some incentive to
install energy recovery devices to reduce dependence on fossil
fuels. The EPA has determined that some landfills that could
klk-85\04 1-51
-------
achieve a profit by installing an energy recovery device would
do so even in the absence of a regulation. In cases where
landfills would combust the gas in the absence of the
regulation, the estimate of nationwide impacts of the
regulation should not include the emission reductions and the
negative control costs for these landfills because
• v
installation of controls is not a result of the regulation.
Not all landfills that could make a profit from energy
recovery, however, would install energy recovery devices
•
unless required to apply control by the regulation. As
discussed below, the impacts of the final rule have been
calculated to exclude credit for those landfills that would
control in the absence of the rule.
The EPA prepared a study (Docket No. A-88-09, Item
No. IV-M-2) that concluded that, on average, for each year
between 1992 and 2002, 138 landfills would be expected to use
energy recovery, whether or not a regulation was in place.
These landfills would most likely use energy recovery in
absence of the NSPS and EG and would be the landfills that
would make the most profit by using energy recovery.
Therefore, the EPA decided to remove the 138 most profitable
landfills from the data base used to calculate nationwide
impacts for existing sources.
The costs and profits of energy recovery at a given
landfill vary depending on when the controls are installed and
removed. This time period varies depending on the stringency
of the regulatory alternative because it will take a longer
period of time for the emissions at a given landfill to drop
below a more stringent cutoff level. Using the nationwide
impacts program from the proposal, the control period of each
landfill was varied and total costs were determined for each
period. The control period was varied for each landfill by
running the nationwide impacts program at various stringency
levels which corresponded to different control periods (from a
minimum control period of 15 years to a maximum that varied
kli-85\0* 1-52
-------
with each landfill). A list was generated that contained all
the landfills that were profitable for any control period.
Once the list of profitable landfills was generated, the
most profitable ones were identified and then deleted from the
landfill data base until a number representing 138 after
scaling were removed. Since these landfills represent
voluntary control in the absence of the standard, their
emission reductions do not result from the NSPS and EG.
Therefore, they were removed entirely from the analysis
(including the baseline). Since the most profitable
landfills, rather than the ones that would actually control in
the absence of the regulation, were removed, the analysis
assumes the maximum lost emission reduction and corresponding
lost profit. In reality, not all of the most profitable
landfills are recovering due to other barriers.
For the NSPS, a comparable number of landfills were
removed from the data base of new sources since this data base
effectively replaces the data base of existing sources over
time.
1.3.2.2 Least Cost Modeling. A least cost scenario was
added to the nationwide impacts program to reflect the use of
energy recovery devices in cases where these cost less than
flares. In the least cost scenario portion of the program,
the least cost of the flare, turbine, or internal combustion
(I.e.) engine options was chosen for each landfill. The least
cost decision was made by comparing the costs of using each
control device throughout the entire control period. The
costs for I.e. engines and turbines included revenue from the
sale of the electricity generated. The modeling program then
chose the option that had the least net cost. The results of
the least-cost control option at each landfill are included in
the final nationwide impacts analysis.
Due to the deletion of the most profitable landfills and
the selection of conservative discount rates in the analysis,
the least cost option did not provide lower cost numbers. The
total cost estimates for the two methods were very similar.
kli-85\0* 1-53
-------
Therefore, the chosen options were based on the flare-only
analysis as was done at proposal.
1.3.3 Alternatives to Promulgated Action
The regulatory alternatives are discussed in the preamble
for the proposed standards and guidelines (56 FR 24468;
May 30, 1991) and in chapter 5 of the proposal BID
(EPA-450/3-90-011a). These regulatory alternatives reflect
the different levels of emission control. The regulatory
alternative selected was based on the BDT, considering costs,
nonair quality health, and environmental and economic impacts
for MSW landfills.
The impacts of the proposed regulatory alternatives and
additional alternatives were reevaluated based on the new data
described in the Federal Register supplemental notice of data
availability (58 FR 33790; June 21, 1993) and in response to
public comments. The alternatives reflect different emission
rate cutoffs. The final standard requires control of
landfills with NMOC emissions above 50 megagrams per year.
Other alternatives included the baseline (no NSPS or EG), the
proposed emission rate cutoff (150 Mg/yr), and an alternative
with no emission rate cutoff. Tables 1-1 and 1-2 present the
emissions and cost impacts of the regulatory alternatives for
the NSPS and EG expressed as NPV and annualized values.
1.3.4 Air Impacts
The analysis of the impacts of the NSPS are based on the
landfills projected to begin accepting waste over the first
5 years of the standard. For these landfills, the NPV of the
baseline NMOC emissions are 160,000 Mg, and the NPV of the
baseline methane emissions are 10.6 million Mg. Of the
roughly 900 landfills estimated to open during the first
5 years, controls will be required at approximately 5 percent
of the facilities. The estimated NPV of the emission
reductions are 79,000 Mg (50 percent) and 3.9 million Mg
(37 percent) for NMOC and methane, respectively. For existing
landfills affected by the EG, the NPV of the baseline NMOC
emissions are 2.1 million Mg. The NPV baseline methane
klk-85\0* 1-54
-------
CO
SS
O
CQ CO
co >
.2*82
i is >••-
1 ** *
*z£ 3
i Sj;r S
c. -S* a
Jf
.2 off
fli
ill
41
|s
i*«
fe B a
•" ^ ^
° I s
in e •-
S S ^
§ §
I
S.Q
O J3
a in o
a «- in
f I
I g
E
in
CM
§ 5
I *
' I
£ t
u *-
\ 1
H- C
O O)
C
a
••-
a w
tl B)
"O •—
3 E
o
u
klk-85\04
1-55
-------
fa
o
to
2
O
EJ
D
o
s
to
2 O
O W
H
to w
CO X
H EH
W fa
O
Q
2 CO
2 U
>
tO H
EH EH
8S
II
E W
HS
w
EH <
frt
wj
8i
fa EH
°3
> D
04 U
2 u
£ &
Q
CO
•
OJ
1
rH
U
(J
CQ
rs
§ .
18*11
i « i -
x 8-g a
81==!
J «• r - i
4-» K
£
&
IK?
«5s|
w « >-.~
i ' •= "S
«•-*-• §
*-» H- *
8-8^ •
Is
u
Cfl
Of U
L. (0 ^
JS g SLU
"-Si-S
i. _r ** — -
o i *• «
•s5T 1
8 « "
u
g J
o o.
agj
s — *
^i
*-8°
1 = =
f — •
*- -^
£ 5
^s
^
c 2
5 <» *
'» S s1
CA '^
•^ 4^ n
g U |
•f .S
z '£
**
81 C
^
c«*
L. j
O X
**• ."
«j n!
35
II?
ill
a!1
•» *-» i
" •£
•- h- 0
(NJ Kt tO
ro K1 «j
1
: a fc 3
«- 0 O-
: « * z
N. O
: S 5f 2
S £ S
c> «-' ro
(
1
§ S C
| -o CM c\
• -^ c
u
a •*-
S 1
•- 4.
"* -° - *
>
*^ ^
O •^I
U
1 1
« U
g .§
'Z 2
1 *
f I
(/> ** V
tfl O H-
* S- o
i 5 S
u
H- C
O & V
(1 '« •
8 * g
n a 8
1 « «
« 1 -5
521
£ 2 £
0 J3 0
klk-SS\04
1-56
-------
emissions are 120 million Mg. Of the 7,300 existing
landfills, controls would be required at roughly 4 percent.
The estimated NPV of the emission reductions are 1.1 million
Mg (53 percent) and 47 million Mg (39 percent) for NMOC and
methane, respectively.
The NSPS and EG are based on reductions of NMOC
• \
emissions; however, landfill gas primarily consists of methane
and carbon dioxide. Although the methane reductions achieved
by these rules were considered as ancillary benefits in the
*
analysis, these reductions do have positive global climate
change impacts. A potent greenhouse gas, methane is about
20 times more effective at trapping heat in the atmosphere
than carbon dioxide (over a 100 year time horizon). Landfills
are the largest anthropogenic source of methane emissions in
the U.S., constituting about 40 percent of total emissions.
President Clinton has committed to reducing emissions of
greenhouse gases to 1990 levels by the year 2000 and, in
October 1993, released the "U.S. Climate Change Action Plan"
for achieving that goal. The MSW landfills NSPS and EG are an
important component of the Climate Change Action Plan because
of the significant greenhouse gas reductions they provide.
Other relevant components of the Climate Change Action Plan
include the EPA Landfill Methane Outreach Program (hotline
phone (202) 233-9042) to encourage more widespread utilization
of landfill gas as an energy source, and the Department of
Energy's Landfill Methane Research Development and
Demonstration (RD&D) Program. Taken together, the goal of
these Climate Change Action Plan actions will lead to methane
reductions equivalent to over 6 million metric tons of carbon
in the year 2000.
Many constituents of NMOC in MSW landfill emissions are
carcinogenic or can cause other adverse health effects as
discussed in chapter 2 of the Background Information Document
for the proposed standards (EPA-450/3-90-011(a), March 1991).
The reduction in landfill emissions may result in a reduction
klk-85\04 1-57
-------
of the risks from potential exposure to these constituents in
the vicinity of the regulated landfills.
The use of energy recovery devices for the control of MSW
landfill emissions has the potential to reduce secondary air
impacts from electric utility plants by reducing the energy
requirements for these plants. This is because the air
impacts of electric energy generation from coal and oil-fired
units are larger than those of LFG-fired energy generation.
Landfill gas-to-energy projects are regarded as pollution
prevention because energy is being recovered from a nonfossil
fuel source while reducing the emissions of toxics, NMOC, and
methane. The EPA prepared an analysis (Docket No. A-88-09,
Item No. IV-B-5) that looks at the secondary air impacts and
electricity generation due to the NSPS and EG. If all
landfills affected by the rule used energy recovery, the
energy value available for electricity generation would be
0.18 quadrillion BTU's (quads) in 2000 and 0.20 quads in 2010.
To illustrate the significance of these potential energy
values, comparisons were made using recent DOE statistics
(i.e., Annual Energy Outlook with Projections to 2010, 1/93).
The potential energy of landfill methane for sites affected by
this rule is equal to 1.1 percent in 2000 and 1.2 percent in
2010 of the annual consumption of coal by U.S. electric
utilities (i.e., 16.2 quads of coal were consumed by electric
utilities in 1990). The potential methane to be reduced from
this rule compared to the annual consumption of petroleum by
U.S. electric utilities is 15 percent in 2000 and 16 percent
in 2010 (i.e., 1.23 quads of petroleum were consumed by
electric utilities in 1990).
There are additional benefits associated with use of this
nonfossil fuel source such as the potential offsets from
electric power plants. The estimate of electricity production
for the sites predicted to use energy recovery (not including
those sites determined to be profitable or already utilizing
energy recovery) is 2.7 kWh x 109 for the year 2000 and 2010.
This would result in a reduction in emissions from electric
klk-85\0* 1-58
-------
power plants of greenhouse gases such as carbon dioxide (CC>2)
and tropospheric ozone precursors, criteria pollutants
including sulfur dioxide (802), nitrous oxides (NOX), and
carbon monoxide, and toxics such as mercury. Assuming
recovery of all the gas that is available, there is
potentially a savings of 1.7 million tons of C(>2 «in 2000 and
2010. There is also a potential reduction of 0.5 thousand
tons of SC>2 from landfills. These reductions may be used by
electric .utilities in reducing the compliance cost to meet the
CAA requirements for SO2 emissions. There is also a potential
savings of 5 thousand tons of NOX although these emissions may
be partially offset by emissions of NOX resulting from the
combustion of landfill gas. Currently, data are insufficient
to calculate the net reductions. The EPA has research
underway through the Office of Research and Development (ORD)
to develop a methodology for use by States in considering the
offset in emissions associated with landfill gas utilization
projects so that the overall environmental benefits of these
projects are considered in permitting applications.
Certain by-product emissions, such as NOX, CO, SOX» and
particulates, may be generated by the combustion devices used
to reduce air emissions from MSW landfills. The types and
quantities of these by-product emissions vary depending on the
control device. However, by-product emissions are very low
compared to the achievable NMOC and methane emission
reductions. Chapters 4 and 6 of the proposal BID
(EPA-450/3-90-01la, March, 1991) present additional
information about the magnitude of potential secondary air
impacts.
1.3.5 Other Environmental Impacts
1.3.5.1 Water. Landfill leachate is the primary
potential source of water pollution from an uncontrolled
landfill. Although there is not sufficient field test data to
quantify the effect of gas collection on leachate composition,
the amount of water pollutants present as NMOC in the leachate
may be reduced under these standards and guidelines.
ktt-85\0* 1-59
-------
When LFG is collected, organics and water are condensed
inside the header pipes of the gas collection system. This
water also contains NMOC and various toxic substances present
in the LFG. The pH of this condensate is normally adjusted by
adding caustic at the landfill and then routing it to a public
treatment facility. This increases the amount of% these
substances entering wastewater treatment plants. There is
insufficient data available to quantify this effect on the
public water supply at this time.
1.3.5.2 Solid Waste. The final NSPS and EG will likely
have little impact on the quantity of solid waste generated
nationwide. The required controls do not generate any solid
waste. However, the increased cost of landfill operation
resulting from the control requirements may cause greater use
of waste recycling and other alternatives to landfill
disposal, leading to a decrease in landfill use. However, is
not possible to quantify such and impact at this time.
1.3.5.3 Implications of the Rulemaking for Superfund.
Municipal solid waste landfill sites comprise approximately
20 percent of the sites placed by the EPA on the National
Priorities List (NPL). Often, remedial actions selected at
these sites include venting methane and volatile organic
contaminants, and airborne emissions are treated if determined
necessary to protect human health and the environment.
The final NSPS and EG may affect remedial actions under
Superfund for MSW landfills. Section 121(d)(2) of
Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) requires that remedies comply with the
substantive standards of applicable and "relevant and
appropriate" requirements (ARAR's) of other environmental
laws. "Applicable" requirements specifically address a
hazardous substance, pollutant, contaminant, remedial action,
location, or other circumstance at a Superfund site.
"Relevant and appropriate1' requirements are not legally
applicable requirements, but may address problems or
situations sufficiently similar to those encountered at the
klk-85\
-------
Superfund site so that their use is well suited to a
particular site. See 40 CFR 300.5 (55 FR 8666, 8814, 8817,
March 8, 1990).
These air emission regulations will apply to new MSW
landfills, as well as to those landfills that have accepted
waste since November 8, 1987. This date in 1987 is the date
on which permit programs were established under the Hazardous
and Solid Waste Amendments of RCRA. For CERCLA municipal
landfill remediations, the substantive requirements of these
regulations may be considered potential ARAR's based on site-
specific factors. These NSPS and EG may be applicable for
those MSW landfill sites on the NPL that accepted waste on or
after November 8, 1987, or that are operating and have
capacity for future use.
1.3.5.4 Energy. Affected and designated landfills with
NMOC emission rates of 50 Mg/yr or more are required to
install a gas collection system and control device. The gas
collection system would require a relatively small amount of
energy to run the blowers and the pumps. If a flare is used
for control, auxiliary fuel should not be necessary because of
the high heat content of LFG, commonly 1.86 x 107 J/scm
(500 Btu/scf) or more. If a recovery device such as an
I.e. engine, boiler, or gas turbine is used, an energy savings
would result.
1.3.5.5 Control Costs and Economic Impacts. Nationwide
annualized costs for collection and control of air emissions
from new MSW landfills constructed in the first 5 years of the
standards are estimated to be $4 million. The nationwide
annualized cost of the EG would be approximately $90 million.
In comparison to other solid waste-related regulations, the
nationwide costs of the recently promulgated RCRA subtitle D
rule are estimated to be $300 million per year and the
estimated nationwide costs of the MWC rules promulgated in
1991 are estimated to be $170 million per year for new
combustors and $302 million per year for existing combustors.
kli-85\0« 1-61
-------
For NMOC, the average cost effectiveness is $l,200/Mg and
the incremental cost effectiveness of going from a 150 Mg/yr
emission rate cutoff to a 50 Mg/yr cutoff is $2,900/Mg for new
landfills. For existing landfills, the average cost
effectiveness is $l,200/Mg NMOC and the incremental cost
effectiveness is $3,300/Mg NMOC.
Preliminary economic analysis indicates that the annual
cost of waste disposal may increase by an average of
approximately $0.60 per Mg for the NSPS and $1.30 per Mg for
the EG. Annual costs per household would increase
approximately $2.50 to $5.00 on average, when the household is
served by a new or existing landfill, respectively.
Additionally, less than 10 percent of the households would
face annual increases of $15 or more per household as a result
of the final EG. However, the EPA anticipates that many
landfills will elect to use energy recovery systems, and costs
per household for those areas would be less. The EPA has
concluded that no households would incur severe economic
impacts. For additional information, please refer to the
regulatory impact analysis (Docket No. A-88-09, Item
No. IV-A-7) and chapter 3.0 of this document.
klk-85\04 1-62
-------
2.0 SUMMARY AND RESPONSE TO PUBLIC COMMENTS RECEIVED ON THE
PROPOSED STANDARDS AND GUIDELINES
2.1 INTRODUCTION x
The public comment period for the proposed NSPS and EG
was from May 30, 1991, to August 1, 1991. A total of
60 letter's commenting on the proposed standards and guidelines
were received. Comments were provided by industry
representatives, governmental entities, environmental groups,
and private citizens. These comments have been recorded and
placed in the docket for these rulemakings (Docket
No. A-88-09, categories IV-D and IV-G). Category IV-G differs
from category IV-D in that it documents correspondence
received after the close of the comment period. Table 2-1
presents a listing of all persons submitting written comments,
their affiliation, and the recorded Docket Item No. assigned
to each comment letter.
In addition, five persons presented oral comments on the
proposed standards and guidelines at a public hearing held in
Research Triangle Park on July 2, 1991. A verbatim transcript
of the comments on the public hearing has been prepared and
placed in Docket No. A-88-09, Item No. IV-F-1. Category IV-F
contains public comments pertaining to the public hearing.
Table 2-2 presents a listing of all persons presenting
comments at the public hearing, their affiliation, and the
docket item number assigned to each speaker.
Comments made at the public hearing or submitted in
writing are summarized and responses are provided in
sections 2.2 through 2.19 of this chapter. The comments are
grouped by subject areas, and the organization of topics is
similar to the organization of the proposal preamble for the
new source performance standards and guidelines (56 FR 24468;
May 30, 1991).
klk-85\04 2-1
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
Docket item number3 Commenter and affiliation
IV-D-1 Mr. Edward W. Repa, Ph.D.
National Solid Wastes *
Management Association
1730 Rhode Island Avenue, NW
Washington, D.C. 20036
•
IV-D-2 Mr. David Armstrong
6544 Whispering Pines Drive
San Jose, California 95120
IV-D-3 Mr. Gregory W. Burrows, M.S.
Laboratory Director
FLI Environmental Services
446 Broad Street
Waverly, New York 14892-1445
IV-D-4 Mr. Christopher Frank
Resource Management Agency
Government Center
Administration Building, L #1710
800 South Victoria Avenue
Ventura, California 93009
IV-D-5 Mr. Charles Collins
Administrator, Air Quality Division
Department of Environmental Quality
Herschler Building
122 West 25th Street
Cheyenne, Wyoming 82002
IV-D-6 Mr. Mark H. Bobman
Assistant Director
Bristol Resource Recovery Facility
Operating Committee
75 Twining Street
Bristol, Connecticut 06010
IV-D-7 Mr. Gary L. Smith, P.E.
Vice President
Cummings and Smith, Incorporated
Post Office BOX 43073
Upper Montclair, New Jersey 07043
kli-85\04 2-2
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
(CONTINUED)
Docket item number3 Commenter and affiliation
IV-D-8 Mr. Dale K. Phenicie %
Manager of Environmental Affairs-North
Georgia-Pacific Corporation
Post Office Box 105605
Atlanta, Georgia 30348-5605
IV-D-9 Mr. Bob Van Deman, P.E.
Department of Solid Waste Management
Pinellas County
Board of County Commissioners
Post Office Box 21623
St. Petersburg, Florida 33742-1623
IV-D-10 Mr. John W. LaFond
President
Quadrel Services, Incorporated
10075 Tyler Place #9
Ijamsville, Maryland 21754
IV-D-11 Mr. Fred S. Kemp
Program Manager
International Fuel Cells
Post Office Box 739
South Windsor, Connecticut 06074
IV-D-12 Mr. Edwin H. Seeger
Michael A. Poling
Prather Seeger Doolittle & Farmer
1600 M Street, NW, 7th Floor
Washington, D.C. 20036
IV-D-13 Mr. William Juris
Division of Air Pollution Control
State of Ohio Environmental Protection
Agency
Post Office Box 1049
Columbus, Ohio 43266-0149
IV-D-14 Mr. James H. McCoy
Total Petroleum, Incorporated
Denver Place North Tower
999 18th Street, Suite 2201
Denver, Colorado 80202-2492
kli-85\04 2-3
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
(CONTINUED)
Docket item number3 Commenter and affiliation
IV-D-15 Mr. Lynne A. Plambeck *
Co-Secretary Laser Coalition
Landfill Alternatives Save
Environmental Resources
23942 Lyons Avenue, Suite 103-353
Newhall, California 91321-2444
IV-D-16 Mr. Jerry T. Joseph
Senior Environmental Engineer
Westinghouse Electric Corporation
Resource Energy Systems Division
2400 Ardmore Boulevard
Pittsburgh, Pennsylvania 15221
IV-D-17 Mr. R. Darryl Banks
Deputy Commissioner
New York State Department of
Environmental Conservation
50 Wolf Road
Albany, New York 12233
IV-D-18 Mr. Rufus C. Young, Jr.
Burke, Williams & Sorensen
611 West Sixth Street, Suite 2500
Los Angeles, California 90017
IV-D-19 Mr. Michael J. Barboza, P.E.
Chairman
ASCE Task Committee on Air Toxics
Emissions
1015 15th Street, NW, Suite 600
Washington, D.C. 20005
IV-D-20 Mr. Patrick Kirsop, P.E.
Plan Review Unit Leader
State of Wisconsin
Department of Natural Resources
Post Office Box 7921
Madison, Wisconsin 53707-7921
klk-85\(H 2-4
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
(CONTINUED)
Docket item number3 Commenter and affiliation
•
IV-D-21 Mr. Michael Baly, III
President
American Gas Association
1515 Wilson Boulevard
Arlington, Virginia 22209
IV-D-22 Mr. Charles K. Weiss, Chief
Bureau of Sanitation
Baltimore County Government
Department of Public Works
111 West Chesapeake Avenue
Towson, Maryland 21204
IV-D-23 Mr. Raymond F. Pelletier
Director
Office of Environmental Guidance
Department of Energy
Washington, D.C. 20585
IV-D-24 Mr. David R. Wooley
Executive Director
Pace University School of Law
Center for Environmental Legal Studies
78 North Broadway
White Plains, New York 10603
IV-D-25 Mr. H. Lanier Hickman, Jr., P.E.
Mr. Donald J. Borut
Mr. Larry E. Naake
Local Government Solid Waste Action
Coalition
Post Office Box 7219
Silver Spring, Maryland 20910
IV-D-26 Mr. Richard L. Echols
Director of Operations, Gas Systems
Browning-Ferris Industries
Post Office Box 3151
Houston, Texas 77253
klk-85\04 2-5
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
(CONTINUED)
Docket item number3 Commenter and affiliation
IV-D-27 Ms. Sue M. Briggum
Director of Governmental Affairs
Waste Management of North America,
Incorporated
3003 Butterfield Road
oakbrook, Illinois 60521
IV-D-28 Mr. Thomas L. Connelly, P.E.
121 Orange Ridge Drive
Longwood, Florida 32779
IV-D-29 Mr. James K. Hambright
Bureau of Air Quality Control
Commonwealth of Pennsylvania
Department of Environmental Resources
Post Office Box 2357
Harrisburg, Pennsylvania 17105-2357
IV-D-30 Mr. Thomas A. Kraemer, P.E.
CH2M Hill
Seattle Office
777 108th Avenue, NE
Bellevue, Washington 98004
IV-D-31 Mr. Mark B. Beizer, P.E.
Vice President
SCS Engineers
3711 Long Beach Boulevard
Ninth Floor
Long Beach, California 90807
IV-D-32 Mr. Ralph E. Chandler
Executive Director
California Integrated Waste Management
Board
1020 Ninth Street, Suite 100
Sacramento, California 95814
klk-85\04 2-6
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
(CONTINUED)
Docket item number3 Commenter and affiliation
IV-D-33 Ms. Deborah A. Sheiman
Resource Specialist
Ms. Marika Tatsutani
Research Associate
Natural Resources Defense Council
1350 New York Avenue, NW
Washington, D.C. 20005
IV-D-34 Mr. John H. Gulledge
Solid Waste Management Department
County Sanitation Districts of
Los Angeles County
Post Office Box 4998
Whittier, California 90607-4998
IV-D-35 Mr. Peter R. Karasik, P.E.
DEP/DSWM
101 Monroe Street, 6th Floor
Rockville, Maryland 20850-2589
IV-D-36 Mr. Dan B. Magoun
Vice President
Environmental Affairs
6231 McBeth Road
Fort Wayne, Indiana 46809
IV-D-37 Mr. Peter D. Venturini
Stationary Source Division
Air Resources Board
1102 Q Street
Post Office Box 2815
Sacramento, California 95812
IV-D-38 Mr. Mohsen Nazemi, P.E.
Senior Engineering Manager
South Coast Air Quality
Management District
9150 Flair Drive
El Monte, California 91731
klk-85\04 2-7
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
(CONTINUED)
Docket item number3 Commenter and affiliation
IV-D-39 Mr. Edward W. Repa, Ph.D. %
National Solid Wastes Management
Association
1730 Rhode Island Avenue, NW
Washington, D.C. 20036
IV-D-40 Mr. Larry D. Henry, P.E.
Maintenance Engineer
The City of Wichita
Department of Public Works
455 North Main Street
Wichita, Kansas 67202
IV-D-41 Mr. James C. Franklin
Manager, Flare Systems
IT McGill Pollution Control Systems
2700 East 51st Street
Tulsa, Oklahoma 74105
IV-D-42 Mr. Marvin Hempleman
Mr. Darrel A. Heider
Twin Falls County Board of County
Commission
425 Shoshone Street, North
Twin Falls, Idaho 83303-0126
IV-D-43 Ms. Jane Levine
Deputy Commissioner for Legal Affairs
The City of New York Department of
Sanitation
125 Worth Street, Suite 728
New York, New York 10013
IV-D-44 Mr. Francis J. Schwindt
State Department of Health and
Consolidated Laboratories
Post Office Box 5520
Bismarck, North Dakota 58502-5520
klk-85\04 2-8
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
(CONTINUED)
Docket item number3 Commenter and affiliation
IV-D-45 Ms. Marsha McLean s
President
S.C.V. Canyons Preservation Committee
24519 Breckenridge Place
Newhall, California 91321
IV-D-46 Mr. James C. Street
Commissioner of Public Works
Lexington-Fayette Government Building
200 East Main Street
Lexington, Kentucky 40507
IV-D-47 Ms. Jane Levine
Deputy Commissioner for Legal Affairs
The City of New York Department of
Sanitation
125 Worth Street, Suite 728
New York, New York 10013
IV-D-48 Mr. Edward Peterson
Environmental Activities Staff
General Motors Corporation
General Motors Technical Center
30400 Mound Road
Warren, Michigan 48090-9015
IV-D-49 Mr. Edward W. Elam
City Manager
Manager Lucas Monroe County Landfill
City of Chariton
115 South Main Street
Chariton, Iowa 50049
IV-D-50 Ms. Linda G. Stuntz
Deputy Under Secretary
Policy, Planning and Analysis
Department of Energy
Washington, D.C. 20585
2-9
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
(CONTINUED)
Docket item number3 Commenter and affiliation
IV-D-51 Mr. William Juris '%
Division of Air Pollution Control
State of Ohio Environmental Protection
Agency
Post Office Box 1049
Columbus, Ohio 43266-0149
IV-D-52 Mr. Brad Jones
Saguache County Administrator
Saguache County
Land Use Department
Post Office Box 326
Saguache, Colorado 81149
IV-D-5^ Mr. Michael E. McDaniel, R.s.
Rockingham County Department of Public
Health
Rockingham County Governmental Center
Route 8, Box 701-J
Reidsville, North Carolina 27320
IV-D-54 Mr. Leonard D. Verrelli
State of Alaska
Department of Environmental
Conservation
Division of Environmental Quality
Post Office Box O
Juneau, Alaska 99811-1800
IV-D-55 Mr. Michael R. Lake
Chief of Engineering
Air Pollution Control District
9150 Chesapeake Drive
San Diego, California 92123-1095
IV-D-56 Mr. George N. Kay a
Director of Public Works
County of Maui
Department of Public Works
200 South High Street
Wailuku, Maui, Hawaii 96793
kDc-85\0* 2-10
-------
TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
(CONCLUDED)
Docket item number3 Commenter and affiliation
IV-D-57 Mr. Jonathan Greenberg *
Browning-Ferris Industries,
Incorporated
1150 Connecticut Avenue, N.w.
Suite 500
Washington, D.C. 20036
IV-G-1 Ms. Dawn M. Campbell
The Solid Waste Association of
North America
Post Office Box 7219
Silver Spring, Maryland 20910
IV-G-2 Senator Joseph I. Lieberman
Senate Office Building
Washington, D.C. 20510
IV-G-3 Mr. Lanier Hickman, Jr., P.E., D.E.E.
Executive Director
The Solid Waste Association of
North America
Post Office Box 7219
Silver Spring, Maryland 20910
kl*-85\04 2-11
-------
TABLE 2-2. LIST OF PUBLIC HEARING SPEAKERS ON THE PROPOSED
STANDARDS OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
Docket item numbera Commenter and affiliation
IV-F-3 Mr. Edward W. Repa, Ph.D.
National Solid Wastes Management
Association
1730 Rhode Island Avenue, NW
Washington, D.C. 20036
IV-F-4 * Mr. Robert Peters
The Solid Waste Association of
North America
Post Office Box 7219
Silver Spring, Maryland 20910
IV-F-5 Mr. Jeff Douglas
Waste Management, Incorporated
1155 Connecticut Avenue, N.W.
Suite 800
Washington, D.C. 20036
IV-F-6 Mr. Rick Oakley
Mr. Richard EchoIs
Browning-Ferris Industries,
Incorporated
1150 Connecticut Avenue, N.W.
Suite 500
Washington, D.C. 20036
aThe docket number for this project is A-88-09. Dockets are
on file at the EPA Headquarters in Washington, D.C.
klk-85\0« 2-12
-------
On June 21, 1993, the EPA published a notice in the
Federal Register (58 FR 33791) providing information on
additional data being used in the development of the final
NSPS and EG for MSW landfills. The additional data that were
made available for public comment included: (1) An updated
data base of site-specific landfill information from which k,
L0 pairs are calculated and CNMQC values are selected (the k,
Lo data base); (2) revised modeling methodologies used to
calculate k values which are then used to estimate nationwide
impacts; and (3) the incorporation of energy recovery in the
modeling of nationwide impacts. The public comment period for
this notice was from June 21, 1993, to July 21, 1993. A total
of seven letters commenting on the additional data were
received from industry representatives, governmental
entities, academia, and a private citizen. These comment
letters have been recorded and placed in the docket for these
rule makings (Docket No. A-88-09, Category IV-L). Table 2-3
presents a listing of all persons submitting written comments,
their affiliation, and the recorded docket item number
assigned to each comment letter. The comments that were
submitted are integrated with the comments and responses to
the proposed NSPA and EG provided under sections 2.3 through
2.19 of this chapter.
2.2 GENERAL COMMENTS
2.2.1 Definitions
Comment; Two commenters reguested that definitions of
the terms "enclosed combustor" and "sufficient extraction
rate" be included in the definitions section, S 60.751.
Response: After considering the commenters' suggestions,
the EPA added definitions in $ 60.751 for the terms "enclosed
combustor" and "sufficient extraction rate."
Comment; One industry commenter (IV-D-27) recommended
changing the following definitions in the proposed regulations
to make them consistent with existing solid waste (RCRA)
definitions: "commercial solid waste"; "controlled landfill";
kllc-85\04 2-13
-------
TABLE 2-3. LIST OF WRITTEN COMMENTERS ON THE NOTICE OF
AVAILABILITY FOR THE PROPOSED STANDARDS
OF PERFORMANCE FOR MUNICIPAL
SOLID WASTE LANDFILLS
Docket item number3 Commenter and affiliation
IV-L-01 Mr. Kurt W. Rieke
Assistant General Counsel
Ogden Projects, Incorporated
Post Office Box 2615
Fairfield, New Jersey 07007-2615
IV-L-02 Mr. H. Lanier Hickman, Jr.
Executive Director
The Solid Waste Association
of North America
Post Office Box 7219
Silver Spring, Maryland 20910-7219
IV-L-03 Mr. Kurt W. Rieke
Assistant General Counsel
Ogden Projects, Incorporated
Post Office Box 2615
Fairfield, New Jersey 07007-2615
IV-L-04 Mr. Thomas L. Connelly
121 Orange Ridge Drive
Longwood, Florida 32779
IV-L-05 Dr. Ramana K. Rao
Senior Engineer
Montgomery County, Department
of Environmental Protection
101 Monroe Street
Rockville, Maryland 20850
IV-L-06 Mr. Bharat Mathur
Chief, Bureau of Air
State of Illinois
Environmental Protection Agency
2200 Churchill Road
Springfield, Illinois 62794-9276
IV-L-07 Mr. David R. Wooley
Executive Director
Pace University School of Law
Center for Environmental Legal Studies
78 North Broadway
White Plains, New York 10603
kli-85\04 2-14
-------
"design capacity"; "industrial solid waste"; "municipal solid
waste landfill"; and, "sludge."
Another conunenter (IV-D-32) indicated that the definition
of "controlled landfill" is not clear and should be restated
to say that "controlled landfills" are those landfills with
operating collection and control systems in place.
Furthermore the commenter requested the term "construction
permit" in the definition for design capacity be changed to
"operating permit."
Response; The terms applicable to this regulation are
defined in $ 60.751. The definitions for "commercial solid
waste", "industrial solid waste", and "sludge" are identical
to the definitions contained in the RCRA regulations. The
terms "controlled landfill" and "design capacity" are defined
in this MSW landfill NSPS regulation, but not under RCRA. The
term "municipal solid waste landfill" is defined within these
regulations to assist in determining applicability with the
NSPS; RCRA defines the term "municipal solid waste landfill
unit" for applicability under RCRA.
As for the definition of "controlled landfill," a
landfill is considered controlled at the time a collection and
control system design plan is submitted. Thus, a collection
and control system does not have to be operational for a
landfill to be controlled under this definition. The
definition of design capacity has been revised to state that
the design capacity will be specified in the construction or
operating permit. If the maximum design capacity is not
specified in the permit, the reporting requirements now allow
it to be calculated using good engineering judgment.
Comment; One commenter (IV-D-27) suggested that the EPA
eliminate the use of the term "permanently closed landfill"
within the preamble discussion since the definition of "closed
landfill" means essentially the same thing. Another commenter
(IV-D-32) indicated that the definition of "closed landfill"
in the proposed regulation differs from their State's
definition of "landfill closure," and also does not address
klk-85\04 2-15
-------
the common practice of closing discrete sections of the
landfill as they become full. The commenter noted that these
units are typically closed according to an approved plan and
are no longer subject to new regulations in his State. The
commenter requested clarification of this issue and suggested
that certification by a knowledgeable engineer or geologist
occur prior to considering a landfill closed.
Response: The definition of "closed landfill" contained
in the final regulation means a landfill in which no
additional solid wastes will be placed in the future. If
additional solid wastes need to be placed in the landfill, a
notification of modification [5 60.7(a)(4)] must be filed and
the landfill will no longer be considered a closed landfill.
In order to be considered closed, a landfill must also meet
the criteria of 40 CFR 258.60. The term "permanently closed
landfill" is not contained in the preamble to the final
regulation.
Although discrete sections of a landfill may be certified
as closed for purposes of RCRA, these sections are
contributing to the overall NMOC emission rate of the entire
landfill and remain potentially affected by this regulation
because the overall NMOC emission rate is the basis for
applicability under these regulations.
Comment: One commenter (IV-D-39) requested that the term
"readily accessible" records be defined.
Response; Records in S 60.758 of the final NSPS can be
either paper or electronic records. Host records must be kept
for 5 years. The final rule specifies that these records may
be kept either on-site or off-site if they are retrievable
within 4 hours. A few types of records must be kept readily
accessible for the life of the landfill or equipment. These
records may also be maintained either on-site or off-site.
2.2.2 Wording of the Standards
Comment; Several commenters (IV-D-23, IV-D-25, IV-D-27,
IV-D-32, IV-D-34) noted places within the Federal Register
notice that appeared to contain typographical errors or
klk-85\04 2-16
-------
erroneous cross references. Two commenters (IV-D-23, IV-F-6)
noted that S 60.753 of the proposed NSPS refers to the methane
generation rate constant as 0.02/yr and S 60.758 refers to the
methane generative rate as 0.2/yr.
Response; The final regulations were reviewed and
typographical errors and erroneous cross references were
corrected.
Comment; Two commenters (IV-D-22, IV-D-32) asked for
clarification about the term "DM in S 60.753(a)(3)(ii)(A),
Tier 2, of the proposed NSPS, wondering if it is the same D
defined in Method 2E.
Response; The commenter was referring to an equation
contained in Tier 2 at proposal. This equation was removed
from Tier 2, in an effort to simplify the Tier 2 requirements.
In the final regulation, Tier 2 requires the owner or operator
to determine the NMOC concentration using a specified sampling
procedure. The regulation requires at least 2 sample probes
to be installed per hectare of landfill surface that has
retained waste for at least 2 years. Areas of nondegradable
solid waste should be avoided when installing the sample
probes. No more than 50 sample probes are required,
regardless of the size of the landfill. If more than
50 samples are taken, then all samples must be used in
determining the NMOC emission rate. The landfill owner or
operator will collect and analyze one sample of landfill gas
from each probe to determine the NMOC concentration using
Method 25C.
Comment; One commenter (IV-D-4) indicated that the
nomenclature for CNMQC should be referred to in a more
consistent manner throughout the proposed regulation. The
commenter further maintained that references to NMOC
concentrations and nomenclature be stated as ppmC (carbon
equivalent) as in Method 25C. The commenter asserted that if
the conversion factors are changed to consistently reflect the
carbon equivalent (instead of hexane as it is stated) then
klk-85\04 2-17
-------
changes within the regulation will need to be made to reflect
this.
Response: The EPA has reviewed the regulation between
proposal and promulgation to remove any ambiguity regarding
the use of the term Cjnjoc- Tne conversion factors in the
final regulation for NMOC consistently reflect the hexane
• *
equivalent.
Comment:: One commenter (IV-D-38) suggested that "or
within 1 year after necessary State and local permits are
issued, whichever is later" be added to S 60.752(b)(2)(ii).
This paragraph requires the installation of LFG collection and
control systems within 1-1/2 years of design plan submittal or
notification of intent to install a collection and control
system. The commenter stated that the permit process is very
time consuming.
Response; The EPA considers the timeframes provided in
the final NSPS and EG to be reasonable, based on section 111
concerns. As stated in the preamble to the proposed
regulations, the time allowed between submittal of the design
plan and installation of the collection and control system
takes into consideration necessary lead time for obtaining and
installing the system components. Whether or not a particular
landfill must also go through a permitting process and how
time consuming that process may be will vary from State to
State, and this is best dealt with at the State level when the
plans for implementing the NSPS and EG are developed.
Section 2.14.1 contains additional information on compliance
times.
Comment: One commenter (IV-D-19) indicated the
regulation should clearly state that 98 percent emission
reduction refers to reduction of NMOC collected by the gas
collection system, not 98 percent of all landfill-generated
gases.
Response; All references to 98 percent emission
reduction within the NSPS and EG refer to reduction of NMOC in
the collected gas.
klk-85\04 2-18
-------
Comment; One commenter (IV-D-26) indicated that the RIA
should be revised for the final rule. The commenter stated
that the conclusions in the RIA are sometimes not referenced
and that the document contains some careless and biased text.
The commenter also suggested that the revised edition should
disclaim the first edition.
Response: The RIA has been reviewed and revised in
conjunction with the final rule. The final RIA is included in
Docket A-88-09 as Item No. IV-A-7. The EPA has made every
•
effort to address pertinent issues in a fair and unbiased
manner.
2.3 SELECTION OF THE SOURCE CATEGORY
2.3.1 Statutory Authority to Regulate
Comment; One commenter (IV-D-06) contended that RCRA
subtitle 0 is the proper arena for addressing MSW landfill
emissions and that this standard should not come under
section 111 of the CAA. A second commenter (IV-D-18),
however, expressed agreement with the EPA in listing MSW
landfills as a source category under Act section lll(b)(1)(A).
The second commenter (IV-D-18) agreed with the proposed
regulation that for the purposes of ascertaining the NMOC
emission rate and design capacity, the entire landfill and all
its emissions should be considered one landfill, i.e, the
affected facility.
Two commenters (IV-D-5, IV-D-55) argued that MSW
landfills should be regulated under section 112, the NESHAP
program, rather than under section ill. One commenter
(IV-D-55) contended that air emission regulations in that
State were the result of concern for toxic air impacts, health
concerns and fire hazards that had no particular correlation
to landfill size. The commenter (IV-D-55) cited an example of
a school playground built on top of a closed landfill, where
students and teachers had reported illnesses correlating with
emission episodes. The commenter (IV-D-55) noted a variety of
section 112 HAP's that are often found in LFG.
klk-85\04 2-19
-------
Two conunenters (IV-D-5, IV-D-44) stated that because NMOC
exist in relatively insignificant amounts in their States, the
proposed regulation would be an unnecessary burden and strain
on scarce resources. One of these conunenters (IV-D-44)
maintained that landfill regulations should fall under the
control of State and local air pollution agencies. Another
commenter (IV-D-42) stated that methane gas and/or leachate
has never been produced in significant amounts in their area,
and did not appreciate a mandatory "methane gas regulation."
Response: The regulation of MSW landfill emissions
originally was considered during deliberations under a RCRA
subtitle D rulemaking. In 1987 the Administrator decided to
regulate these emissions under the authority of the Clean Air
Act. After further consideration, the EPA announced in the
Federal Register on August 30, 1988 (53 FR 33314) their
decision to regulate MSW landfill emissions under section 111
of the CAA.
As discussed in the proposal preamble, section 111 NSPS
and EG are issued for categories of sources which cause, or
contribute significantly to, air pollution which may
reasonably be anticipated to endanger public health or welfare
(56 FR 24468; May 30, 1991). Evidence from the EPA and State
studies show that MSW landfills release air pollutants that
have adverse effects on both public health and welfare. For
this reason, the EPA chose to regulate MSW landfill emissions
under section 111.
The RCRA subtitle D establishes a framework for
controlling the management of nonhazardous solid waste.
Because the intent of this rule is to regulate emissions of
landfill gas, and not solid waste, this regulation has been
developed under the CAA instead of under RCRA. Some
requirements in the RCRA subtitle D regulation are referenced
within the NSPS and EG and are necessary to achieve compliance
with these regulations.
The CAA as amended (1990 Amendments) revised the approach
for regulating HAP emissions under section 112 and requires
klk-85\04 2-20
-------
that the EPA publish a list of categories of sources having
the potential to emit 10 or 25 tons/yr in the aggregate of any
HAP listed in section 112. MSW landfills are a source of such
HAPs and therefore were included on the source category list.
MSW landfills not emitting above the regulatory cutoff under
the NSPS and guidelines may still meet the section 112
• x
criteria. Thus, the HAP emission potential of such landfills
and the need for control of HAP's from municipal landfills
will be evaluated in the future as part of that program.
Additionally, State and local governments may address
site-specific issues under their own air toxics programs.
Despite the listing under section 112, it was decided to
continue with the section ill regulations because they address
the range of health and welfare concerns related to landfill
gas emissions. Furthermore, because they have already been
proposed, section 111 regulations can be promulgated more
quickly than section 112 regulations thereby achieving
benefits of earlier control at landfills with NMOC emissions
above the cutoffs. In response to commenters who are
concerned about the burden of the regulation, the final
regulation includes both a design capacity exemption and an
emission rate cutoff to determine if controls are required
thereby focusing control efforts on those landfills where the
greatest emission reductions can be achieved and control is
most reasonable. This will greatly reduce the burden on small
landfills who would incur high costs if they were required to
apply controls, but would see only small emission reductions.
The proposed regulations are not methane gas regulations.
The designated pollutant of concern is MSW landfill emissions
because it has been determined to be a threat to the
environment and public health. The group of compounds, NMOC,
was chosen as the surrogate pollutant for landfill emissions
because NMOC includes those LFG constituents of most concern
to the environment and public health. Only landfills emitting
NMOC greater than the regulatory cutoff are required to
install controls.
klk-85\04 2-21
-------
2.3.2 Health and Welfare Concerns
Cop^fn't; A number of commenters addressed the EPA's
consideration of the five areas of concern regarding potential
adverse health and welfare effects of air emissions from MSW
landfills. The five major effects of MSW landfill air
emissions are: (1) human health and vegetation effects caused
•»
by ozone formed from nonmethane organic compound emissions,
(2) carcinogenicity and other possible noncancer health
effects associated with specific MSW landfill emission
•
constituents, (3) green house effects from methane emissions,
(4) explosion hazards, and (5) odor nuisance.
Three commenters (IV-D-26, IV-D-39 and IV-F-3, IV-F-4)
stated that the five concerns have not been quantified or
properly justified in the EPA's analysis. Two commenters
(IV-D-26, IV-F-4) stated that these five concerns can better
be addressed using a performance standard.
Several commenters (IV-D-2, IV-D-17, IV-D-18, IV-D-45,
IV-D-55, IV-L-1) expressed concern for the effects MSW
emissions can have on public health. One commenter (IV-L-1)
contended that the proposed NSPS was insufficiently inclusive
and stringent to protect public health and the environment.
The commenter (IV-L-1) requested that the EPA reconsider
whether the CAA compliance and health risk implications have
been addressed by the proposed NSPS. Two of the commenters
(IV-D-18, IV-D-45) argued that LAER and not BDT should be used
in nonattainment areas to better protect public health.
Another commenter (IV-D-55) was concerned that the proposed
regulations would divert funding from small, more hazardous
landfills to larger, remote landfills which are less hazardous
to public health. A third commenter (IV-D-2) suggested
increasing the stringency of standards for landfills located
3 or fewer miles from a residence.
One commenter (IV-D-19) requested that basic information
regarding the magnitude of effects a landfill and its
emissions may have on the surrounding land area be considered
in the final regulation because it could either justify
klk-85\0« 2-22
-------
additional controls or justify the reduction of controls.
Another commenter (IV-D-39) added that the proposal BID
provides information on the effects of ozone on laboratory
animals and vegetation, but does not quantify the role
landfill air emissions play in endangering public health or
welfare. Therefore, the contribution of landfill air
•»
emissions to ozone formation and its resulting impact on the
environment and human health cannot be determined. Also, the
conunenter argued that existing studies have shown that the
•
carcinogenic risks associated with landfill emissions are
actually very low (1 x 10~6 to 1 x 10~8) and that such low
risk sources are not typically regulated.
The commenter (IV-D-39) stated that no data are presented
on the contribution and effects that landfill-derived methane
plays in the alleged "global warming" process. The commenter
stated that the existing data suggest that landfills as a
methane source are a small component of the total methane
generated and released into the atmosphere.
Another commenter (IV-D-17) was concerned with the danger
imposed on nearby residential areas by the existence of toxic
organic compounds in LFG and the threat of explosion due to
volatile gases.
The commenter (IV-D-39) stated that although the
explosive hazard of methane migration into on-site and off-
site buildings is well documented, the control of methane for
explosive hazards is already addressed in subtitle D of RCRA.
Therefore, this regulation will do little to reduce the
potential of such hazards since appropriate controls are
already mandated under existing law.
The commenter (IV-D-39) stated that odor control
practices are presently being addressed in the revisions to
RCRA subtitle D. The commenter also asserted that the
technical data presented and the analysis performed do not
clearly justify the regulation. Also, the commenter critiqued
the five areas of concern identified by the EPA as
justification for the standard.
klk-fl5\04 2-23
-------
The commenter (IV-D-39) stated that the courts have
rightfully insisted that a variety of factors, such as costs,
health and environmental impacts, nonair quality impacts, and
energy requirements be evaluated in formulating new source
standards pursuant to section 111. The commenter asserted
that the proposed standards are inconsistent, both with the
expressed terms of section ill and the regulations promulgated
thereunder.
Response; The EPA is regulating MSW landfill emissions
•
to address threats to public health and welfare posed by
landfill emissions on a nationwide basis. Recognizing that
individual MSW landfills contribute to these nationwide health
and welfare concerns, the EPA has fully considered these
issues for this section 111 rulemaking. The EPA addressed the
five areas of concern to public health and welfare to the
extent possible using the available sources of information at
proposal. The proposal preamble, BID, and RIA provided the
basis for addressing these concerns as well as discussions on
cost benefit analysis.
As stated in the proposal preamble (see 56 FR 24469;
May 30, 1991), NSPS implement section lll(b) of the CAA and
are issued for categories of sources which cause or contribute
significantly to air pollution which may reasonably be
anticipated to endanger public health or welfare. In
addition, an NSPS requires these sources to control emissions
to the level achievable by BDT considering costs and any
nonair quality health and environmental impacts and energy
requirements. As such, the proposed standards conform to
section 111 of the CAA. All of the relevant factors were
considered and the EPA's decisions regarding these factors
were summarized in the preamble to the proposed NSPS
(56 FR 24468; May 30, 1991).
Section 111 standards deal with emissions of concern
through establishing technology-based, not risk-based,
standards. The level of control required under the
section 111 NSPS program is BDT. The NSPS may assist States
kLk-85\0* 2-24
-------
in achieving the NAAQS, but this is not the focus of the NSPS.
States can institute more stringent requirements for any
source to address State or local issues, including provisions
requiring the use of LAER. Under the NSR program, either BACT
in attainment areas or LAER in nonattainment areas are
determined on a site-specific basis. The BACT or LAER must,
• *
at a minimum, be equivalent to the BDT under any applicable
NSPS, but may also be more stringent.
The commenter concerned about smaller, more hazardous
•
landfills focussed on air toxics. As discussed in the
previous paragraph, air toxics at landfills emitting above the
regulatory cutoff will be reduced by these regulations, and
the EPA also intends to address HAP emissions at MSW landfills
specifically under section 112. Additionally, the inclusion
of MSW landfill emissions on the PSO significance list and the
promulgation of these NSPS and guidelines should provide
funding relief to State air program boards. Title V of the
CAA required that States collect fees from all sources subject
to regulation under the CAA, and the EPA promulgated this
operating permit program on July 21, 1992 (57 FR 32250).
As stated in the preamble to the proposed regulations,
landfills emit methane, which has been identified as a
greenhouse gas contributing to global climate change. Because
the rate and magnitude of these changes are uncertain, a
quantitative assessment of climate change impacts was not
performed. However, methane reductions were quantified, and
the NSPS and guidelines together will reduce methane emissions
by over 47 million Mg (expressed as NPV). The President's
1993 Climate Change Action Plan calls for the promulgation of
the landfill gas rule.
Explosion hazards for methane at the boundary of the
landfill are addressed directly under RCRA. This regulation
would supplement RCRA and reduce the threat of explosions all
over the landfill site, as well as offsite at controlled
landfills through the destruction of LFG. Hazardous air
pollutants from landfills would also be reduced through these
kli-85\04 2-25
-------
regulations, and municipal landfills have also been listed for
future regulatory development under section 112 of the CAA
(see 57 FR 31576; July 16, 1992).
Because of the difficulty in describing HSW landfill
emission levels that can be causally linked to the risk of
fire or explosion, the EPA did not attempt to quantify these
' %
effects. Chapter 2 of the proposal BID describes these
effects in greater detail. Although RCRA addresses explosion
hazards, not all landfills will be subject to RCRA. Explosion
•
potential will be reduced at all landfills that must install
collection and control systems as a result of these
regulations. All of these concerns, whether addressed
qualitatively or quantitatively, contributed to the EPA's
decision to regulate MSW landfills under section 111 of the
CAA.
Because odor perception and impact is subjective, it is
difficult to quantify the degree of unpleasantness of odor.
Therefore, the EPA has addressed the adverse effects of odors
qualitatively in its analysis. Because NMOC are a precursor
to ozone, the NSPS and EG should provide a reduction in ozone
formation. However, the effect of NMOC on ozone formation has
not been accurately quantified and has only been addressed
qualitatively.
The commenter asked that the effects one particular
existing MSW landfill has on surrounding areas be considered
in the regulation. However, NSPS under section 111 of the CAA
must require the application of BDT that addresses public
health and welfare concerns at all affected landfills. The
BDT established for this rulemaking requires all affected
landfills to install collection and control systems if their
calculated NMOC emission rates exceed the emission rate
cutoff. Also, State and local agencies have the flexibility
to consider any site-specific public health and welfare
concerns in developing their own regulatory and permitting
programs and establishing additional control requirements.
kli-85\0* 2-26
-------
One comment er (IV-L-1) encouraged the EPA to
immediately begin to conduct studies in preparation for the
8-year review. The commenter discussed pollutant-specific
cancer risks of benzene and vinyl chloride.
Response ; The section 111 standards are technology
based standards and as such do not address specific health
risk. While section 111 requires periodic review* of
standards, that review does not include health risk
estimation; rather, it addresses whether the standards reflect
BDT, considering technology advances and other factors. The
commenter may be confusing the section 111 (NSPS) and
section 112 (NESHAP) programs. The CAA requires a review of
residual risk 8 years after NESHAP are promulgated under
section 112. This provision does not apply to NSPS.
Municipal landfills are listed as a source category that emits
hazardous air pollutants and NESHAP will be developed in the
future .
2.4 SELECTION OF THE AFFECTED AND DESIGNATED FACILITIES
Comment : Three commenters (IV-D-17, IV-D-39, IV-D-48)
cautioned the EPA that controlling landfills which have
accepted waste after November 8, 1987 and which may have
closed prior to May 30, 1991 is unfair, and would pose an
economic burden, because these landfills will have no means to
raise the funds needed for installation of collection and
control systems. One of the commenters (IV-D-17) suggested
that a requirement be included in the final rule for an
economic and fiscal analysis to determine the feasibility of
applying the emission guidelines "retroactively." Given that
a retroactive cutoff date was set, the commenter suggested
that an alternative cutoff date, ranging from 1965 to 1970,
might be appropriate for landfills large enough to warrant
regulation, because such landfills might still be producing
NMOC.
Two commenters (IV-D-26, IV-D-39) recommended that an
existing facility be defined as a facility that had received
waste on or after May 30, 1991, the date of proposal, instead
kUc-85\04 2-27
-------
of November 8, 1987. One of the commenters (IV-D-26) stated
that the costs for compliance with the November 8, 1987 cutoff
date are significant. One of the commenters (IV-D-39) argued
that owners of closed facilities historically have not been
required by the EPA to implement controls and that the
environmental benefit gained by the inclusion of. Bolder
landfills would be much less than the benefit of controlling
open landfills because older closed landfills typically have
emission Jevels that are much lower than newer sites.
The commenter (IV-D-39) asserted that locational data for
these facilities is not readily available and would be
difficult to obtain because most States did not maintain such
records despite the requirement of the 1984 RCRA amendments.
Additionally, the commenter reported that a comparison of
recent surveys shows that States were not capable of reporting
the same data consistently and that differences between data
sets were sometimes as great as 100 facilities.
Response; As discussed in section IV.D of the proposal
preamble under "Selection of the Affected and Designated
Facilities," the EPA requested comment about the ability of
States to identify those landfills which may have closed after
November 8, 1987, and the appropriateness of this date as a
cutoff for applicability. The EPA typically does not
establish operating standards through section lll(d) of the
CAA for sources no longer operating. However, during the
development of these standards and guidelines, the EPA found
that a typical landfill is likely to generate landfill gas at
a maximum rate at, or soon after, closure and that the
generation rate would steadily decline thereafter.
A significant number of landfills have closed after
November 8, 1987, prior to 1991, and may still have emissions
above the regulatory cutoff that pose a risk to public health
and welfare. For this reason, the EPA considers it
appropriate to regulate these landfills under section lll(d)
of the CAA.
klk-85\04 2-28
-------
Faced with the administrative and policy complexities of
regulating closed facilities, the EPA looked for an approach
that was likely to lead to reasonable success in reducing
emissions without establishing unreasonable requirements.
The Hazardous and Solid Waste Amendments to RCRA of 1984
required States to establish a permit program or other system
of prior approval to ensure that facilities receive household
hazardous waste or small quantity generator hazardous waste
are in compliance with 40 CFR part 257, "Criteria for
Classification of Solid Waste Disposal Facilities and
Practices." This permit program was to be established by
November 8, 1987. The EPA views this permit program as a
readily available resource for States to use in implementing
today's guidelines and judged States would be able to identify
active facilities as of this date. For these reasons, the EPA
has defined a designated facility as an existing landfill that
received waste on or after November 8, 1987, or has additional
capacity which may be filled in the future.
With regard to the suggested cutoff dates of 1965 to
1970, many States lack the information necessary to identify
all landfills that closed that long ago.
Section ill of the CAA defines a new source as one
commencing construction on or after the date of proposal
(May 30, 1991) of the applicable standard. Therefore, the
distinction between new and existing MSW landfills was not
determined as a part of this rulemaking, but was set at the
date of proposal, as mandated by the CAA.
The focus of the rulemaking is control of the designated
pollutant, MSW landfill emissions, at new and existing MSW
landfills. Any landfill subject to the emission guidelines
accepting waste or having capacity available for future waste
acceptance between November 8, 1987, and the proposal date
would have to exceed the regulatory cutoff before installation
of collection and control systems would be required.
Even though the actual decline in the emission rate
varies from landfill to landfill, in general landfills closing
2-29
-------
prior to 1987 emit at declining rates, while landfills closing
after the 1987 cutoff date may warrant control. However, as
stated in the proposal preamble, the model and information
presented in the proposal preamble and BID are appropriate for
application to older landfills, and States are encouraged to
use them to assess the emission potential of any closed
landfills of concern under the emission guidelines.
The EPA found that the majority of landfills are either
part of a municipal system or else corporately owned. There
•
are few independently owned and operated landfills. If an
individual landfill does not have adequate resources, a State
may consider making a case-by-case showing for the landfill,
or a group or class of landfills, that a less stringent
emission guideline is warranted. Under 40 CFR 60.25(f), a
State may apply a less stringent standard based on
unreasonable cost, physical impossibility, or other factors
specific to the landfill or class of landfills that make
application of a less stringent standard significantly more
reasonable. States may submit such case-by-case
determinations to the EPA for review as part of the submittal
of their plan to implement the EG.
Comment: One commenter (IV-L-1) recommended that all
design and construction plans for new landfills, or expansions
of existing landfills, contain active landfill gas collection
and control systems, regardless of the anticipated disposal
capacity.
Response; The final rule requires only those landfills
that exceed the emission rate cutoff of 50 Mg/yr to install a
collection and control system to control emissions of NMOC.
The EPA encourages owners or operators of new landfills or
existing landfills that are in the process of expanding to
begin planning for collection and control systems if they
anticipate ever having a design capacity that would exceed
2.5 million Mg or 2.5 million m3 and an emission rate of
50 Mg/yr. The EPA has included a design capacity exemption of
2.5 million Mg or 2.5 million m3 in the final rule and
kLk-85\04 2~30
-------
estimates that this will exempt approximately 90 percent of
affected landfills from the recordkeeping and reporting
requirements of the rule. These landfills are excluded for
reasons described in section 2.4.1.1. The final rule focuses
on control of larger landfills where there is the greatest
emission reduction potential and reduces the regulatory burden
on small entities. The EPA will not require an owner or
operator to include active landfill gas collection and control
systems in their design plans if they do not anticipate
exceeding the design capacity exemption and the 50 Mg/yr
control applicability cutoff. The MACT standard that must be
promulgated in the future for municipal landfills will examine
whether smaller landfills have significant hazardous air
pollutant emissions.
2.4.1 Exemptions from Control
Comment; One commenter (IV-D-8) requested exemption from
these regulations, based on the administrative and cost
burdens, for all industrial/municipal solid waste disposal
facilities where less than 15 percent of waste is MSW.
A second commenter (IV-D-6) stressed that landfills that
accept large amounts of MWC ash should be regulated under RCRA
subtitle 0 rather than under the CAA, and that landfills
accepting only MSW should be regulated by the proposed
standards.
A third commenter (IV-D-27) recommended that the
regulation allow owners and operators to demonstrate that some
older portions of the landfill may be virtually nonproductive
and, therefore, not warrant the placement of collection wells.
The commenter suggested that exclusion provisions similar to
those established for asbestos deposition be crafted.
Additionally, the commenter proposed that gas generation rate
calculations should not be required for areas excluded from
the system since the rates could only be determined from an
active collection system.
In addition, the commenter (IV-D-27) proposed that the
provisions for exempting areas of asbestos deposition in the
kl*-65\04 2-31
-------
guidelines be extended to the NSPS, noting that asbestos will
continue to be disposed of in MSW landfills. The commenter
further noted that documentation of the deposition area may
not be available, and warned that erroneous drilling through
asbestos may occur if the owner is required to keep the
excluded areas below 1 percent emission potential. The
• %
commenter recommended greater flexibility in excluding areas
of asbestos deposition.
Another commenter (IV-D-39), however, recommended the
*
elimination of the exclusion for areas of a landfill based on
the presence of asbestos and nondegradable materials. The
commenter asserted that these exclusions will lead to unequal
enforcement of the regulations and not provide the level of
environmental protection that the EPA seeks. The commenter
argued that an operator hypothetically could, through the
acceptance of very small quantities of asbestos, landfill the
waste so that most of the landfill's area is excluded from the
requirements pertaining to the installation of gas recovery
wells. Also, since many landfills have disposed of
nondegradable material as the landfilling operations
progressed and few have records of disposal location,
regulatory enforcement of this section would be difficult.
Response: While it is true that many MSW landfills have
accepted non-MSW in some quantity, the regulations do not
exempt these landfills from the standard because the LFG
emissions depend on the organic material in the waste, not on
the origin of the waste. The emissions of concern, LFG
emissions, result primarily from degradation of organic
material, which may result from deposition and degradation of
MSW, industrial solid waste, commercial solid waste,
conditionally exempt small quantity generator waste or
nonhazardous sludge. All of these wastes may contribute to
LFG emissions. Therefore, the MSW landfill definition must
include all of these constituents, and does not include a
percentage MSW cutoff.
klk-85\04 2-32
-------
The final regulations are structured to require
collection and control based on NMOC emission potential, and
the emission rate calculations are based on the amount and age
of the waste, regardless of its origin. As provided in
S 60.754 of the NSPS, the emission rate calculations include
summing the individual emission rates from each yearly submass
• *
of waste material. Areas may be excluded from the collection
system only through three mechanisms: documentation must be
provided for nonproductivity due to age, nonproductivity due
to nondegradable nature (e.g., cement, MWC ash), and the
presence of asbestos.
Older "nonproductive" organic waste will likely be
emitting at some low rate, and the regulation would exempt
such an area from control provided that its calculated
emission potential can be shown to be less than 1 percent of
the overall emission potential of the landfill. If the age
and mass of an older area is known, the current emission rate
for that submass can be calculated and compared to the overall
emission rate. Since emissions from each yearly submass
decline with age, the actual ages of these submasses will
govern how many of these submasses may be excluded from
control before the 1-percent limit is reached. The data and
calculations that provide the basis for excluding such areas
must be documented and provided to the Administrator upon
request.
Landfills receiving wastes other than, or in addition to,
MSW may, however, be able to demonstrate an emission rate
below the regulatory level, via the provisions for the
exclusion of nondegradable areas of the landfill. These
provisions would likely exempt dedicated landfills receiving
only demolition waste or MWC ash because such landfills may
not emit above the emission rate cutoff. Nondegradable waste,
such as cement or MWC ash, is exempted because it is not
contributing to the LFG emission rate, and these provisions
specify that the mass of nondegradable refuse is not to be
included when estimating emissions. In the final NSPS, the
kli-85\04 2-33
-------
1-percent condition is not required of asbestos or
nondegradable material, provided that documentation is
provided on the nature, date of deposition, location, and
amount of material deposited. This approach is preferable to
excluding landfills that accept a certain percent of MWC ash
from the NSPS and EG because landfills that accept a mixture
• %
of MWC ash and MSW may still emit significant amounts of
landfill gas from the MSW and may warrant control. Regulating
such landfills only under RCRA instead of the NSPS and EG
would not necessarily address the air pollution concerns.
The intent of the exclusion for asbestos was to avoid a
known, documented hazard, rather than to permit circumvention
of the regulations based on either a hunch about the presence
of asbestos or poor management practices. The EPA will allow
exclusions based on asbestos deposition only for those cases
where such deposition is managed and fully documented.
As discussed in the previous response, a State may make a
case-by-case showing for the landfill, or a group or class of
landfills, such as a landfill where a very small percent of
the waste is MSW, that a less stringent emission guideline is
warranted if the criteria in 40 CFR 60.25(f) are met.
Comment; One commenter (IV-D-54) stated that alternative
standards should be proposed for facilities in cold regions
that have reduced their LFG emissions by using designs that
freeze the waste. The commenter suggested that if a
temperature monitoring system can assure that the waste is
stored at a temperature below freezing, then a gas collection
and control system should not be required.
Response; The regulation provides for a situation such
as this. A low NMOC emission rate can be verified through
sampling and analysis using Method 25C. If the NMOC emission
rate is below 50 Mg/yr, installation of a gas collection and
control system is not required. However, if the NMOC
concentration is high enough to result in a calculated NMOC
emission rate above the emission rate cutoff, the landfill
would warrant control under these regulations. For existing
klk-85\04 2-34
-------
The design capacity exemption was re-evaluated in the interim
between proposal and promulgation, and has been revised to
2.5 million Mg or 2.5 million m3.
The proposed design capacity cutoff of 100,000 Mg of
waste was chosen so that no landfill would be exempted and
have actual emissions above the emission rate cutpff. Several
comments were submitted requesting an increase in the
exemption level. An increase would relieve additional owners
and operators of small landfills from the emission estimation
and control requirements. In addition to the comments,
changes to the data base and the emission modeling values
prompted the design capacity exemption level reevaluation.
The new design capacity analysis evaluated a range of options
from 500,000 Mg to 4.0 million Mg of waste. Two important
considerations in the selection are the number of landfills
exempted and the amount of potential NMOC emission reduction
lost from the exempted landfills.
The 2.5 million Mg exemption level would exempt
90 percent of the existing landfills while only losing
15 percent of the total NMOC emission reduction. Therefore,
2.5 million Mg was chosen since losing 15 percent of the
emission reduction is a reasonable tradeoff to relieve as many
small business and municipalities as possible from the
regulatory requirements while still maintaining significant
national emission reduction. The 2.5 million Mg exemption
level excludes those landfills, both public and private, would
be at least able to afford the costs of collection and control
systems. The lowest value considered, 500,000 Mg, only allows
slightly more than 1 percent of the total emission reduction
potential to go unregulated; however, only 62 percent of the
landfills are exempted. Under this option, a large proportion
of landfills would be required to perform annual emission
calculations and would experience significant recordkeeping
and reporting burdens, even though they would never reach
50 Mg/yr and would never be required to install controls.
The highest capacity value considered, 4.0 million Mg, would
kllc-85\04 2-37
-------
allow over 20 percent of the potential emission reduction to
go unregulated.
Since some landfills record waste by volume and have
their design capacities calculated in volume, EPA also
established an equivalent design capacity exemption of
2.5 million m3 of waste. The density of landfilled solid
waste varies from landfill to landfill depending on several
factors, including the compaction practices. Any landfill
that reports waste by volume and wishes to establish a mass
design capacity must document the basis for their density
calculation.
All MSW landfills above the design capacity exemption
level (maximum design capacity) must periodically calculate
their annual NMOC emission rate to determine if controls are
warranted. See responses in section 2.15, "Reporting and
Recordkeeping", for consideration of the resulting paperwork
burden. The EPA remains convinced that control of landfills
smaller than the design capacity exemption is a reasonable
tradeoff to focus effort on those landfills with the highest
potential for emission reductions. However, States have the
freedom to require additional monitoring, LFG collection, or
control to address State concerns. At the time MACT standards
are developed for landfills under section 112 of the CAA, EPA
will assess the HAP emission potential from landfills and
decide whether smaller landfills warrant control for HAP
emissions.
2.4.1.2 Co-combustion of Landfill Gas
Comment; One commenter (IV-D-16) suggested that the
proposed regulations do not account for the possibility that
some enclosed combustors could be used for combusting fuels
other than LFG. In particular, the commenter was concerned
about MWC's subject to the NSPS for MWC's that also combust
LFG. The commenter recommended that the standards be changed
to exclude facilities which are already regulated by other
standards of performance and/or emissions guidelines
promulgated under the CAA from the requirements of these
klk-85\04 2-38
-------
landfills, a State could establish an alterative emission rate
cutoff based on the criteria provided in 40 CFR 60.24(f).
Comment; After the notice of data availability
(58 FR 33790, June 21, 1993), one commenter (IV-L-5) inquired
as to what types of materials other than nonprocessible
materials (white goods), could be excluded from consideration
as MSW for modelling air emissions for use in determining
whether collection and control systems should be installed.
Response; The EPA did not request comment on materials
exempted from control in the notice of data availability. The
EPA assumes that by the term nonprocessible materials (white
goods) the commenter is referring to either nondegradable
materials or nonproductive areas. Under S 60.759(a)(3)(i) of
the final rule, segregated areas of asbestos or nondegradable
materials may be excluded from control if documentation is
kept on the nature, date of deposition, amount and, location
of the waste. Nondegradable waste, such as demolition waste
or MWC ash, is exempted because it does not contribute to LFG
emissions. Under S 60.759(a)(3)(ii) of the final rule, older,
nonproductive areas of the landfill may be excluded from
control, if the total of all excluded areas contributes less
than 1 percent of the total amount of emissions from the
landfill and they are documented.
2.4.1.1 Design Capacity Exemption
Comment: Several commenters (listed below) discussed the
proposed design capacity exemption of 100,000 Mg. One
commenter (IV-D-7) contended that because of the current costs
associated with the siting, permitting, and development of
landfills, no additional MSW landfills having design
capacities less than 100,000 Mg will be built. The commenter
said that the exemption level should be raised to 1.0 million
Mg because the calculation method used in the regulation
overestimates NMOC emissions. Two commenters (IV-D-20,
IV-D-54), suggested an exemption level of 550,000 Mg because
they reasoned that landfills smaller than this would not emit
more than 150 Mg/yr anyway. The commenters contended that the
kl*-85\04 2-35
-------
lower exemption level would unnecessarily increase the
regulatory burden of the standard, and will burden small
landfills and State regulatory agencies. Another commenter
(IV-D-51) also argued that the proposed design capacity
exemption level was too low.
One industry commenter (IV-D-27) approved of a design
• %
capacity exemption level of 100,000 Mg, but also noted that
there would still remain considerable burden for small
landfills that would be exempted at Tier 1, noting that about
35 percent of Tier l MSW landfills are never required to
install controls. The commenter applauded the conservative
basis for review of MSW landfills to identify those warranting
gas control and praised EPA's effort to obtain information
from the regulated community. The commenter recommended,
however, that all MSW landfills be evaluated for NMOC emission
rates, instead of only those above the design capacity
exemption level.
Another commenter (IV-D-36) agreed, suggesting that if
LFG is an environmental concern, then all landfills,
regardless of size, should be regulated, or at least monitored
to determine if control is necessary.
Another commenter (IV-D-39) asserted that the 100,000 Mg
cutoff is not based on technical justification or cost/benefit
analyses using NMOC emission data. The commenter stated that
small landfills that are poorly designed and operated may have
emission levels that exceed levels found at large, properly
designed and operated landfills. The commenter asserted that
all owners or operators should be required to report emission
levels that have been certified by an appropriate
professional, such as a professional engineer.
Response: These regulations, including the design
capacity exemption level, are based on NMOC emission
potential. After BDT was determined, the design capacity
exemption was selected to reduce the paperwork burden on
landfills that typically would not have a calculated NMOC
emission rate large enough that controls would be required.
klJt-85\04 2-36
-------
regulations. The commenter also suggested the regulations
should provide a different emission limit for facilities
burning LFG along with other fuels. The commenter requested
that the compliance test method be appropriate for use with
LFG and LFG mixed with other fuels, and noted that
co-combustion may affect the test methods provided in these
regulations.
Response: The EPA does not consider it difficult to
demonstrate either a 98-percent reduction in NMOC or a 20 ppmv
TOC concentration when LFG is combusted in an MWC. Because
the format of the MWC NSPS is a set of emission limits for
individual pollutants, while the format for this NSPS is a
performance standard for total NMOC, the performance tests in
the NSPS for MWC's differ from the performance test provided
in these regulations. When only LFG is fired in a combustor,
it will be subject only to the control requirements of this
NSPS and EG.
In addressing the commenter's concern, the EPA looked for
ways to relieve undue regulatory overlap while still ensuring
that BDT is not compromised. The final regulation clarifies
that alternative methods of compliance demonstration can be
used if approved by the Administrator. For example, for a
situation when both LFG and refuse is combusted in an MWC
simultaneously, a design analysis and any other information
demonstrating that the standards can be continuously achieved
must be submitted to and approved by the Administrator.
In the development of the Hazardous Organics NESHAP (HON)
and previous NSPS for process vents that may be controlled by
routing organic-containing gases to boilers, the EPA
determined that a performance test would not be required for
boilers or process heaters with a design heat input capacity
of 44 MW or greater. Analysis shows that when vent streams
are introduced into the flame zone of these boilers and
process heaters, over 98 percent reduction or an outlet
concentration of 20 ppmv is achieved. Therefore, a
performance test is not necessary. If, however, the gas
klk-85\04 2-39
-------
stream is combusted in a boiler or process heater with a
design heat input capacity of less than 44 MW, a performance
test to demonstrate 98 percent NMOC reduction or 20 ppmv is
still required. The final NSPS has been amended to
incorporate these provisions.
2.4.2 Selection of the Tier Default Values
• %
Comment; Three commenters (IV-D-4, IV-D-7, IV-D-26 and
IV-F-6) contended that the NMOC default concentration of
8,000 ppmv is overly conservative and recommended alternative
concentrations as more representative. One of the commenters
(IV-D-7) referred to tests conducted in humid climates
yielding NMOC concentrations of 200 to 500 ppmv.
Another commenter (IV-D-39) asserted that the default
NMOC concentration value of 8,000 ppmv as hexane is not
justified in the proposal BID, and questioned how it was
derived. The commenter stated that this value should be re-
examined and that the analysis should address differences in
NMOC concentration based on the waste types received at the
landfills.
Another commenter (IV-D-28) alleged that there is no
established technical basis for the refuse decay rate value
(k) of 0.02/yr or the refuse methane generation potential (Lo)
of 230 m3/Mg and, therefore, these values should be excluded
from the regulation until adequate technical justification
exists. A second commenter (IV-F-6) stated that the k value
of 0.02 is too conservative and overstates gas production
rate. A third commenter (IV-D-17) listed the range of
variation for these two defaults and stated that the EPA
should fund contracts to study the variability of the LFG
generation constant, k, and the methane generation potential,
Lo, to see if the variations can be reduced. Another
commenter (IV-D-26) argued that the default k and Lo values
overpredict production of gas, thereby requiring collection
when "real" emissions levels may be very low. The commenter
asserted that the default Lo is the most critical value and
klk-85\0<. 2-40
-------
that the proposed regulation does not allow a calculated value
to be substituted in the estimation.
Response; The default values for use in the tier
calculations were not chosen to be average values. Owners or
operators wanting average values for use in system design or
inventory should use the values published in the latest
version of EPA's AP-42 document. Selection of the default
NMOC concentration provided in the tier calculation was not
based on test data alone. Rather, it was chosen in concert
with the defaults for the methane generation potential (Lo)
and the refuse decay rate constant (k). The objective of the
defaults selection process was to obtain a balance between
lost emission reduction potential and cost of performing the
field tests in Tiers 2 and 3 on a nationwide level as
described in the memorandum entitled "Rationale for Selecting
Tier 1 Default Values" (Docket No. A-88-09, Item No. II-B-33).
More specifically, the default values were selected such that
there is low potential that they will significantly
underestimate emissions for individual landfills (resulting in
less emission control); yet the defaults will not overestimate
emissions by such an extent that a large number of landfills
would be over 50 Mg/yr according to Tier 1 and would undergo
the expense of Tiers 2 and 3 and show that they are actually
below 50 Mg/yr.
It should be noted that the default NMOC concentration
reflects some existing landfills that may have a history of
codisposal of hazardous waste. Data received from codisposal
landfills indicates that the NMOC concentrations from
codisposal sites are typically higher than NMOC concentrations
from nonhazardous MSW landfills. However, because of RCRA
regulations preventing disposal of hazardous waste in MSW
landfills, only NMOC concentrations from landfills that never
accepted hazardous waste were used to characterize landfills
opening after 1987. The NMOC concentrations from landfills
that accepted hazardous waste as well as landfills that never
accepted hazardous waste were both used to characterize
kli-B5\04 2-41
-------
landfills opening through 1987. The memorandum "Methodology
used to Revise the Model Inputs in the Municipal Solid Waste
Landfills Input Data Bases (Revised)" (Docket No. A-88-09,
Item No. IV-M-4) discusses the rationale used to calculate and
select values for k, Lo/ and C^MOC* As discussed in later
comments in this section, the default values have been revised
' %
since proposal.
For data to be used to obtain default k values, the
following had to be available: test year, year landfill
•
opened, year landfill closed (if closed), amount of
refuse-in-place in the test year, refuse acceptance rate, and
the actual methane flow rate. For data to be used to obtain
default NMOC concentrations, the following had to be
available: the total NMOC concentration and associated units
(e.g., ppmv as hexane, ppmv as methane), the methane
concentration and the CO2 concentration (to correct for air
infiltration since landfill gas is primarily methane and CX>2) ,
and the test method used. Also, the test method used had to
be comparable to EPA Method 25C.
Comment; One commenter (IV-L-2) contended that the k,
Lo, and CNMOC values will vary based on more than just
geographic location, which the commenter stated was a
surrogate for precipitation. Other factors the commenter
(IV-L-2) mentioned that could influence the values included:
the categories and relative quantities of waste produced
according to the local economic conditions and emphasis, the
amount and types of materials diverted from the waste stream
by recycling, and other physical characteristics of the region
where the subject landfill is located and their influence on
the design of the landfill. The commenter (IV-L-2) noted that
all or most of the landfills added to the database are from
arid regions.
Response; The commenter is correct in noting that there
are many factors that influence k, Lo, and CNMQC values at
each landfill. The purpose of the MSW landfills data base is
to reasonably represent the variability among landfills in the
klk-85\0* 2-42
-------
U.S. While the EPA agrees that its approach cannot accurately
estimate emissions at a given landfill without additional
site-specific information, the EPA supports the methodology
for emissions estimates on a nationwide basis. All of the
randomly assigned factors were determined from data on
existing landfills, and available literature was ^reviewed to
establish reasonableness criteria for using this information
in the model.
While it would be infeasible to factor every variable
•
into the emissions estimation model, the model does account
for the percentage of landfills in arid versus moist regions.
This was a way to factor the influence of moisture into the
analysis. In order to factor other influences into the
analysis, a large amount of resources and time would need to
be spent and the outcome is questionable. The data on
precipitation and location, however, were readily available.
For further information on arid versus moist k and Lo values
used in the landfills data base, see section 6.0 of the
memorandum "Methodology Used to Revise the Model Inputs in the
Municipal Solid Waste Landfills Input Data Bases (Revised),"
April 28, 1993 (Docket No. A-88-09, Item No. IV-M-4).
Comment; One commenter (IV-L-4) alleged that there is no
established technical basis for the "revised" k value of
0.03 yr-1 or the Lo value of 140 m3/Mg. The commenter
(IV-L-4) cited as reasons: the enactment of Federal final
cover standards which should cause landfills to be "extra
arid," resulting in a decreased k, and the enactment of State
recycling programs, which remove paper and landscaping waste,
resulting in reduced Lo values. The commenter (IV-L-4)
recommended not using the revised k and Lo values in the rule,
but offered no alternative values or methodology.
Response: The k and Lo values are used as input
parameters in the model equation for estimating NMOC emissions
from each landfill in the input data bases. The revised k and
L0 values were derived from known landfill-specific data
obtained from SCAQMD test reports, section 114 letter
klk-B5\04 2-43
-------
responses, ORD studies, and landfill gas to energy data
updated by SWANA. A description of the methodology used to
calculate new k and Lo values can be found in the memorandum
entitled "Methodology Used to Revise the Model Inputs in the
Municipal Solid Waste Landfills Input Data Base (Revised),"
April 28, 1993, (Docket No. A-88-09, Item No. IV-M-4).
The k value of 0.02 yr"1 and Lo value of 230 m3/Mg were
the proposed default values for use in Tier 1 of the rule
where an owner or operator will estimate the annual NMOC
•
generation for a landfill. The k and Lo values of 0.03 yr'1
and 140 m3/Mg are the average k and Lo values in the input
data bases and do not correspond to the default values to be
applied in the rule. Default values were not chosen to be
average values. Owners or operators wanting average values
for use in system design or inventory should use the most
current values published in AP-42.
Default values for the tier calculations are determined
by an optimization analysis between estimated nationwide costs
of performing the tier analyses and total nationwide emissions
reduction of the rule. Defaults that result in greatly
overestimated emissions would result in more landfills
exceeding the 50 Mg/yr applicability level under Tier 1. An
increased number of landfills would then undergo the expense
of Tier 2 and 3 testing. If Tier 1 greatly overestimated
emissions, many of the landfills that did Tier 2 and 3 testing
would find they emit below 50 Mg/yr and are not required to
apply controls; thus, they would incur high test costs and no
emission reduction benefits. On the other hand, if the
defaults underestimate emissions, landfills that actually have
emissions over 50 Mg/yr would escape control. This would
result in less emission reduction than intended. The default
values selected were considered to achieve the best balance
between resulting in control of those landfills that emit over
50 Mg/yr without resulting in overly burdensome national costs
for tier analysis.
klk-85\04 2-44
-------
For the final rule, the default values were revised to
k = 0.05 yr"1; L0 = 170 m3/Mg; CNJJQC = 4,000 ppmv as hexane.
More information on this subject may be found in the
memorandum "Documentation of Small-Size Exemption Cutoff Level
and Tier 1 Default Values (Revised)," April 27, 1995 (Docket
No. A-88-09, Item No. IV-B-10).
The average k and Lo values of 0.03 yr"1 and 140 m3/Mg in
the input data bases were representative of currently existing
landfills.. As discussed in the methodology memorandum listed
above, (Docket No. A-88-09, Item No. IV-M-4), the gas
generation from arid versus moist landfills was considered in
the development of the k and Lo values for each landfill in
the input data bases. Also, the rule allows site-specific k
values to be determined for each landfill if the landfill
chooses to perform a Tier 3 analysis.
The primary criteria effecting Lo of a landfill is the
cellulose content of the refuse. State recycling programs
that remove paper and landscaping waste may effect Lo of
landfills; however, the extent to which these programs will
effect L0 cannot be accurately quantified and currently
available data must be used. However, under
§ 60.759(a)(3)(i) of the final rule, segregated areas of
asbestos or nondegradable materials may be excluded from
control if documentation is kept on the nature, date of
deposition, amount, and location of the waste.
Comment; One commenter (IV-L-7) supported the use of the
maximum Lo at each landfill, instead of the average in
calculating potential landfill emissions. Another commenter
(IV-L-2) objected to limiting the maximum Lo for an individual
landfill that could be greater than 7,000 ft3 methane/Mg of
refuse. The commenter (IV-L-2) also expressed concern because
the data used to determine the range of possible Lo values was
compiled from one source. The commenter (IV-L-7) who
supported the use of the maximum Lo stated that the net result
of the changes to the methodology for calculating generation
potential is a decrease in the total potential gas emissions
klJc-85\04 2-45
-------
nationwide and results in fewer landfills requiring controls.
The commenter (IV-L-7) contended that the same was true for
the results of the revised inputs to the concentration of
NMOC. The commenter (IV-L-7) stated that this was a departure
from the traditional EPA practice of assuming a worst case
scenario in protecting the environment.
• *
Response: The revisions to the methodology for
determining L0 values and CNJJOC values used in the input data
bases provide estimates of methane and NMOC emissions that are
lower than the proposal estimates. The revisions are based on
additional information that was obtained since proposal, and
the EPA believes that the revised estimates more accurately
represent nationwide landfill emissions.
The EPA used the Lo range of 2,000 to 7,000 ft3
methane/Mg refuse to define the minimum and maximum Lo values
that can be assigned to any landfill in the input data bases.
This Lo range, taken from "Methane Gas in Landfills:
Liability or Asset?" presented at the Fourth National Congress
of the Waste Management Technology and Resource and Energy
Recovery, was chosen because it falls within the total range
of L0 values reported in the numerous references reviewed by
the EPA. Therefore, the commenter is incorrect in suggesting
that the range of Lo values came from one source.
Based on a literature review and available data, the EPA
has determined that an L0 range of 2,000 to 7,000 ft3
methane/Mg refuse is appropriate. The literature review
revealed that 7,000 is the upper end of the range that is
typical, and values exceeding this would be unlikely due to
the amount of methane producing material that could be
realistically placed in a landfill and eventually converted to
methane.
Comment: One commenter (IV-L-3) contended that an Lo of
1,700 to 3,500 ft3 methane/Mg wet waste is more appropriate
than the higher L0 of 4,913 ft3 methane/Mg proposed by the
EPA. The commenter noted a 1991 paper by Augenstein and Pacey
that presents an Lo of 1 to 2 ft3 methane/dry pound of waste.
klk-85\04 2-46
-------
The commenter stated that assuming a waste moisture of 20 to
25 percent, translates to an Lo value of 1,700 to 3,500 ft3
methane/Mg wet waste.
The commenter (IV-L-3) mentioned work of Augenstein
(1976a,b), and Chynoweth and Legrand (1991) that have shown an
L0 value on the order of 3 ft3 methane/pound of dry volatile
solids under lab conditions. The commenter (IV-L-3) contended
that with waste at 20 to 25 percent moisture, 25 percent ash,
and the balance volatile organics, the upper limit of Lo can
be calculated based on these lab results to be about 3,500 ft3
methane/Mg.
The commenter (IV-L-3) stated that dry landfill methane
fermentation conditions are more typical and methane
conversion will consequently be less than the potential
maximum. The commenter (IV-L-3) stated that this is supported
by the findings of apparently unaltered material even after
many decades of burial, in several articles by Rathje. In
addition, the commenter (IV-L-3) asserted that shallower
landfills as well as those with more porous covers may be
partly aerobic, reducing methane yield.
The commenter (IV-L-3) acknowledged that there are
numerous projections and calculations by the EPA and their
contractors of methane yields much higher than 3,500 ft3
roethane/Mg. However, the commenter (IV-L-3) contended that
these higher yield projections are stoichiometric calculations
rather than laboratory results with representative solid
waste. The commenter (IV-L-3) stated that actual biological
methane production will be substantially lower than
stoichiometric estimates because much organic material is
undecomposable and much of the degradable fraction is shielded
by lignin. The commenter (IV-L-3) stated that similar points
have been made by Professor Morton Barlaz (Barlaz 1991).
Response: Numerous references were reviewed that
identified values for Lo. These items are summarized in the
memorandum "Methodology Used to Revise the Model Inputs in the
Municipal Solid Waste Landfills Input Data Bases (Revised),"
klk-85\04 2-47
-------
April 28, 1993, (Docket No. A-88-09, Item No. IV-M-4). It was
determined that L0 values are highly variable and difficult to
quantify on a landfill-specific basis.
The range of Lo values recommended by the commenter
(1,700 to 3,500 ft3 methane/Kg) falls mostly within the range
used by EPA (2,000 to 7,000). Also, applying the range of L0
• %
values to the actual emissions data from the 44 landfills
presented in the memorandum indicates that 25 percent of the
landfills would not have a solvable k value at an Lo of
•
3,500 ft3 methane/Mg, indicating that actual L0 values may be
greater that 3,500. This indicates that the larger range of
2,000 to 7,000 ft3 methane/Mg would be more appropriate.
Comment; One commenter (IV-L-2) requested clarification
on the methodology used to calculate k values using the Lo
values, and contended that this process appears to produce k
and Lo values that are proportional to each other.
Another commenter (IV-L-3) noted that the use of lower Lo
values implies higher k values. The commenter acknowledged
that k is back calculated from Lo. The commenter stated that
k and Lo are approximately reciprocal and that the effect of
higher k values and lower Lo values would shorten the
projected term of methane generation, as well as the
cumulative NMOC emission over the long term.
Response: The k and Lo values determined for each
landfill in the data base are based on measured landfill gas
emissions and waste acceptance rate data for existing
landfills. Based on this data, for a given Lo value, a k
value was calculated using the model equation. This gives a k
and L0 value that, when the model equation is used, yields a
gas generation rate equivalent to the measured flow rate.
While these values are related exponentially due to the model
equation, they are not directly proportional or linear to one
another. See "Methodology Used to Revise the Model Inputs in
the Municipal Solid Waste Landfills Input Data Bases
(Revised),11 April 28, 1993, (Docket No. A-88-09, Item
No. IV-M-4) for more information on this topic.
klk-85\04 2-48
-------
Comment; One commenter (IV-L-2) suggested that the upper
limit of the 80th percentile confidence interval on the mean,
and not the median, be chosen for the expected k and Lo
values.
Response: In the period between proposal and
promulgation, the EPA decided that determining a site-specific
potential Lo range for each of the 44 landfills and then using
the median Lo for each landfill would be more representative
of reasonable gas generation potential than using the 20th and
*
80th percentiles equally with the median value, as was done in
the proposal analysis. Using a median L0 value reduces the
potential error in estimating emissions from individual
landfills using the model equation. This eliminates the
possibility of assigning high Lo values to landfills that may
actually have low values, and vice versa. In order to
calculate the upper limit of the 80th percentile confidence
interval on the mean, a distribution of Lo values is
necessary. The Lo value will vary depending upon the
characteristics of the refuse disposed at individual
landfills.
The data available only provided a range of Lo values
that are most likely to exist at landfills. A distribution of
the range of L0 values at landfills in the U.S. was
unavailable and would require a great deal of additional
resources and time to obtain.
Comment; One commenter (IV-L-5) requested clarification
on the input parameters for estimating air emissions from
existing MSW landfills using the model "Landfill Air Emissions
Estimation Model, Version l.l" obtained from the EPA's CTC.
The commenter (IV-L-5) inquired whether the CTC's version 1.1
model is identical to the model used to develop the data in
the EXISCLOS data base.
Response; The CTC's Landfill Air Emissions Estimation
Model (version 2.0, which is the most recent version) uses the
same equation that is used to derive the landfill gas
generation rate for the final rule. Version 2.0 of the CTC
klk-85\04 2-49
-------
model has been revised to include the default values for k,
L0, and CNJJOC used in tne final rule. A copy of the air
emissions estimation model (version 2.0) is available from the
Control Technology Center.
2.4.3 Removal of Controls
Comment; One industry commenter (IV-D-27) disapproved of
the proposed 3-step removal criteria for control systems. The
commenter recommended the use of a single criteria for the
removal of controls: a calculated NMOC emission rate less
•
than the stringency level of 150 Mg/yr demonstrated two times
within a 2-year period, not closer together than 12-months.
Other commenters (IV-D-39, IV-D-48, IV-F-6) disapproved of the
15-year time limit for removal of collection and control
systems. One commenter (IV-F-6) recommended that removal of
controls be allowed as soon as the emission level falls below
the designated rate.
One commenter (IV-D-48) disapproved of the 15-year time
limit for operation of the gas collection and control system
at Superfund sites. The commenter asserted that MSW Superfund
sites have often been closed for 20 to 30 years before site
investigation begins and a need for emission controls is
discovered. The commenter contended that because of the
relatively old age of Superfund sites, 15 years of gas
collection would not give the marginal benefit to substantiate
the operational costs. The commenter also argued that the
operation and maintenance costs generally exceed capital
costs, especially at Superfund sites, because the Btu content
of the gas is often insufficient without the aid of costly
auxiliary fuels. The commenter recommended that the removal
of controls be determined on a site-by-site basis.
Another commenter (IV-D-39) asserted that data justifying
the 15-year minimum operation time of a collection and control
system is not provided and that the 15-year time period
appears to be based on a perceived useful life for the LFG
equipment. The commenter contended that their experience
indicates that the useful life of gas collection equipment
kli-85\0« 2-50
-------
should be based on site specific conditions and attainment of
the emission limitations. The commenter recommended that the
proposed regulation be modified so that adjustments can be
made to the gas collection system based on site-specific
conditions, including cycling the system's operation, or
closing the system down prior to 15 years of operation, as
long as the facility does not exceed the "performance
standard" (i.e., the regulatory cutoff).
Another commenter (IV-D-32), however, disagreed with the
proposed provisions for the removal of controls after as few
as 15 years of operation. The commenter supported a 30-year
period instead, because the 15-year period was inconsistent
with their State's post closure maintenance period for
landfills.
Response: The 3-step removal criteria were selected to
assure that all necessary requirements are met before
collection equipment is removed. First, the landfill must no
longer be accepting waste. This is necessary because landfill
emissions continue to rise until after closure when waste is
no longer being accepted. Second, testing in three successive
periods must demonstrate that NMOC emissions are below the
stringency level of 50 Mg per year. This will require testing
at different times of the year, giving a more realistic
representation of the NMOC emission rate. Moreover, testing
LFG samples taken directly from the collection system is
relatively inexpensive. Two testing periods would not as
clearly describe the NMOC emission rate. Third, the
collection and control system must have been in operation a
minimum of 15 years. The 15-year control period was selected
based on the expected equipment life of the major system
components. It was determined that once the capital costs
were paid and the emission rate fell below the regulatory
emission rate cutoff, the cost of reducing emissions would be
significantly lower relative to the cost for controlling
emissions including capital costs. The SWANA submitted a
survey of LFG collection systems (Docket No. A-88-09, Items
klk-85\04 2-51
-------
No. IV-G-Ol, IV-G-03), indicating that equipment replacement
varied from 5 to 30 years, with vertical well replacement
ranging from 10 to 20 years, and a 30-year life span for
overall recovery systems. Therefore, the EPA continues to
consider the 15-year control period reasonable, given the
additional emission reduction achieved for basic ^operating
costs only.
Superfund sites, however, are typically not actively
receiving, waste. To be subject to either the NSPS or the EG,
a Superfund site would have to have accepted MSW since
November 8, 1987 and emit above the emission rate cutoff. Any
landfill accepting waste since November 8, 1987, that
continues to generate NMOC at 50 Mg/yr or greater will require
a gas collection system under these regulations. In cases
where a gas collection system is required under these
regulations, emission rates are such that the marginal benefit
of gas collection for 15 years would be similar to younger,
closed landfills requiring gas collection. However, special
situations at any site, Superfund or not, can be given special
attention by the State in which the landfill is located.
Any State may require 30 years of gas collection instead
of 15 years, independent of these regulations. The
post-closure maintenance period mentioned by the commenter is
a RCRA provision and the basis for the control period was
determined under a separate program. It should be noted that
MSW landfills are subject to any applicable requirements
contained in rules developed under RCRA as well as the
landfills NSPS and EG developed under the CAA.
2.5 SELECTION OF THE POLLUTANT TO BE REGULATED
Comment; Two commenters (IV-D-3, IV-D-6) argued that
NMOC should not be classified as a surrogate for MSW landfill
emissions because of insufficient data in characterizing NMOC
(IV-D-6) and because NMOC should only be considered as a
substitute for MSW landfill emissions and not as a surrogate
(IV-D-3).
kilc-85\04 2-52
-------
Response; The pollutant to be regulated, MSW landfill
emissions, or LFG, is composed of methane, CO2, and NMOC. The
EPA selected NMOC as a surrogate for determination of control
because NMOC includes those LFG constituents, of most concern.
The nature of the individual compounds commonly found in LFG
and the health concerns they present are discussed in
chapter 2 of the proposal BIO. By controlling NMOC emissions,
the non-NMOC constituents in LFG would also be controlled. By
basing control on NMOC emission rates, the EPA is controlling
•
the subset of landfills having MSW landfill emissions of
greater concern. The EPA, therefore, considers the use of
NMOC as a surrogate for MSW landfill emissions to be effective
and appropriate.
Comment; Four commenters (IV-D-19, IV-D-27, IV-D-29,
IV-D-33) addressed the pros and cons of methane as the
designated pollutant. One commenter (IV-D-19) stated that
methane should be the surrogate for LFG because control of
methane would likely result in the control of NMOC as well.
In addition, methane is easier than NMOC to test and monitor.
Another commenter (IV-D-27) asserted that NMOC also
contributes to ozone nonattainment and the greenhouse effect.
The commenter suggested performing a complete evaluation of
ongoing methane studies, such as those being done by AEERL,
WCRP, and IGBP, prior to subjecting MSW landfills to any
additional requirements.
An environmental group (IV-D-33) recommended that a
separate standard be developed for methane. One commenter
(IV-D-27) noted that some of the arguments made in the
preamble for not regulating methane could also be used as
reasons not to regulate NMOC.
Two commenters (IV-D-25 and IV-F-4, IV-D-34) recommended
that TOC be used as a surrogate instead of NMOC, since it
would include NMOC as well as other MSW emissions, and would
address the global warming, explosion, and fire hazard aspects
of MSW emissions. Additionally, the commenters asserted that
TOC is less variable, and sampling and analysis is much less
kUt-85\0* 2-53
-------
costly. The commenters suggested that the EPA's sensitivity
analysis be repeated to select TOC limits. Another commenter
(IV-D-54) recommended that VOC be used as the surrogate for
MSW landfill emissions instead of NMOC. Other commenters
(IV-D-26, IV-D-27) also suggested adoption of an alternative
method for determining applicability of controls and
•»
well-spacing using TOC as a methane surrogate. The commenters
preferred this method because it will be easy to enforce.
Response; The EPA designated MSW landfill emissions as
the pollutant to be regulated because it contains the various
landfill air pollutants, including methane and NMOC, posing
concern due to adverse health and welfare effects. The NMOC
may contribute to ozone formation and odor problems. Some
NMOC are known or suspected carcinogens, while other NMOC are
known to cause noncancer health effects. Methane was also a
concern, due to the potential it poses for explosions and fire
and global climate change impacts.
The EPA decided not to determine control requirements
based on the methane fraction of MSW landfill emissions
because the NMOC surrogate is more effective than methane in
addressing the broad range of concerns posed by MSW landfill
emissions. The reduction of methane will, however, be a
benefit of these regulations. (Additional methane
considerations are discussed in section 2.18.1, Consideration
of Methane.)
A TOC surrogate may track methane, one of the larger
fractions of the MSW emission mixture more closely, but would
not respond to varying NMOC levels as well as the NMOC
surrogate, because of the dominance of methane. Therefore, a
TOC surrogate would not allow the EPA to tailor the
regulations to the overall environmental concerns of MSW
landfill emissions. There has been considerable concern
expressed about the toxicity of NMOC. Given the requirement
to select BDT considering costs and other impacts, the EPA has
chosen to base these regulations on an NMOC cutoff, to control
the subset of landfills presenting the greater health
kli-85\04 2-54
-------
concerns, rather than base these regulations on emissions of a
more generic surrogate, such as TOC. In this way, the EPA was
able to select BDT (based on a cost and impact analysis)
addressing the landfills that present the greatest overall
environmental concerns at this time.
Finally, the EPA does not agree that a TOC surrogate
would be easier to enforce, because enforcement would depend
on emission calculations, with opportunity for site-specific
testing, whether TOC or NMOC provided the basis for control.
Comment: One commenter (IV-D-54) contended that the EPA
changed the regulated pollutant from VOC to NMOC to force
State air divisions to formulate plans to regulate landfill
emissions using section lll(d) technology-oriented standards.
The commenter also contended that this will subject these
landfills to additional PSD review, which will consume
valuable State resources.
Response; If the EPA had not established a significance
level for MSW emissions for inclusion in 40 CFR 51 and 52, MSW
landfills would be subject to PSD review whenever any increase
in MSW landfill emissions occurred. The 45 Mg/yr (50 tons/yr)
significance level for NMOC in the final rule is comparable in
stringency to the 36 Mg/yr (40 tons/yr) significance level
established for VOC. The EPA estimates VOC to account for
approximately 70 percent of total NMOC from MSW landfills, but
this percentage varies among landfills. Landfills with
emission increases greater than 45 Mg/yr NMOC or greater than
36 Mg/yr VOC would be required to undergo PSD review. The PSD
significance level for landfill emissions was changed from
36 Mg/yr (40 tons/yr) at proposal to 45 Mg/yr (50 tons/yr) to
be more consistent with the previously established
significance level for VOC. The EPA considers the
significance value appropriate for the health and welfare
effects of the MSW landfill emissions.
2.6 SELECTION OF BEST DEMONSTRATED TECHNOLOGY
Comment; One commenter (IV-D-15) requested that the
stringency of the standards be increased, so that better
kli-85\04 2-55
-------
technology could be incorporated. The commenter also
maintained that BAT should be used in place of BDT to
encourage continuing research in emissions control.
Response; These standards and emission guidelines are
promulgated under section 111 of the CAA, which requires the
standards be set based on the application of the BDT
considering costs and any nonair quality health and
environmental impacts and energy requirements, at the time the
standard is promulgated. An NSPS establishes a nationwide
minimum level of control, but it is based on the application
of BDT. States do, however, have the freedom to set more
stringent standards, whether through establishing a lower
regulatory cutoff or requirements for a BACT-type analysis
whenever a new or modified landfill is permitted. These
regulations, however, must conform to the statutory framework
for NSPS. Refer to section 2.6.2 for further discussion on
the selection of the regulatory stringency level.
Comment; One commenter (IV-D-21) stated that the
proposed regulations would discourage owners or operators from
using alternative control devices, because all control devices
except open flares would have to demonstrate compliance by
testing. The commenter suggested that other control
technologies, including energy recovery technologies, should
be defined as BDT. The commenter requested that, at the very
least, additional language and guidelines be added to the
regulation to strongly endorse and encourage energy recovery.
Response: The regulation allows any control system
designed and operated within the parameters demonstrated in
the performance test to reduce NMOC by 98 weight-percent or
reduction to 20 parts per million by volume. The preamble to
the final rule defines combustion control achieving 98 percent
reduction or 20 ppmv as BDT. The rules are not intended to
encourage open flares instead of energy recovery devices. The
regulation does not require testing of open flares because
testing is infeasible. However, flares must be designed and
operated according to specified criteria and visible emission
klk-85\04 2-56
-------
determination is required by 40 CFR 60.18. Additional impacts
analyses of energy recovery technologies were performed after
proposal and the results have been incorporated in the
preamble of the regulation. The nationwide impacts of flare
and energy recovery options are detailed in the memorandum
"Revised Nationwide Impacts for Development of Regulatory
Alternatives" (Docket No. A-88-09, Item No. IV-M-7).
2.6.1 Selection of Best Demonstrated Technology—Passive
Systems
^"•-^"^"^•^™™— *
Comment; One commenter (IV-D-29) requested that the
regulation provide specific criteria and test methods that a
passive venting system must meet to satisfy BDT. The
commenter questioned why the EPA is allowing passive systems
when it has stated in the 1988 Preliminary Draft BID that "gas
captured in a passive system is not amenable to control or
recovery."
Another industry commenter (IV-D-27) argued that passive
systems can be designed to meet BDT, and provided a table
cross-referencing previous submittals providing useful
information on such systems.
One commenter (IV-D-17) stated that the EPA should
demonstrate the relationship between passive and active
collection systems. They further state that if a correlation
exists, passive systems such as landfill vents could be used
to predict the performance of, or need for, active collection
systems.
Response; The EPA investigated the use of passive
systems prior to proposal, and some design guidance was also
provided in chapter 9 of the proposal BID. The EPA assumes
that the 1988 preliminary draft BID commenter IV-D-29 referred
to was an early draft that differs from the BID published at
proposal in March 1991. Although the EPA found passive
systems generally to be less practical and more expensive than
active collection systems, such systems may achieve an
equivalent level of control, provided that the landfill
installs and carefully maintains a liner on all six sides of
ktt-85\04 2-57
-------
the landfill as required under subpart D, section 258.40 of
the final solid waste disposal facility criteria regulation
(56 FR 50978; October 9, 1991). The owner or operator would,
however, need to submit a design plan that demonstrates that
the system provides an equivalent amount of control to an
active system meeting the criteria in § 60.759 of the NSPS.
Section 63.752(b)(2)(ii)(B) includes criteria passive
collection systems must satisfy and a requirement for a design
plan. The relationship between passive and active systems
*
would depend on site-specific landfill characteristics and
system designs. Based on existing information, it is not
practical to establish a correlation. A site-specific design
approval approach is more appropriate.
2.6.2 Selection of the Emission Rate Cutoff
Comment; Several commenters requested a more stringent
emission rate cutoff, while others favored the 150 Mg/yr rate
proposed, and some favored a less stringent standard. Four
commenters (IV-D-18, IV-D-25, IV-D-34, IV-D-44) supported the
proposed regulatory emission rate cutoff of 150 Mg/yr. Some
of these and other commenters (IV-D-15, IV-D-18, IV-D-20,
IV-D-25, IV-D-27, IV-D-34) stated they would support a more
stringent level. One of these commenters (IV-D-20) asserted
that the data provided by the EPA supports a more stringent
level, that this level would not significantly increase the
control period, and that it would be cost-effective. Another
commenter (IV-D-21) stated than an economic analysis including
energy recovery would support a more stringent standard, and
the regulatory cutoff level should be lowered.
Two commenters (IV-D-11, IV-D-33) supported a stringency
level of 25 Mg/yr because of the methane reductions that would
result. One of the commenters (IV-D-11) stated that such an
emission level would reduce 90 percent of NMOC and 80 percent
of methane emissions from MSW landfills. The other commenter
(IV-D-33) presented an analysis to show that NMOC and methane
reduction from landfills emitting above 25 Mg/yr NMOC is
cost-effective, particularly if benefits from abatement of
klk-85\0* 2-58
-------
global warming and energy recovery are considered. One
commenter (IV-L-7) recommended an emission rate cutoff of
25 Mg because only 10 percent of methane generated by
landfills is being burned for energy recovery and the
commenter wanted the rule to encourage the development and
installation of energy recovery systems. Another^ commenter
(IV-D-29) suggested examining a level between 25 Mg/yr and
150 Mg/yr. In particular, the commenter claimed that health
risks posed by landfills between these two cutoff levels may
be significant.
Another commenter (IV-D-39) stated that the BID and RIA
for the proposal do not provide a clear rationale or cost
effectiveness for the selection of a 150 Mg/yr NMOC emission
limit. The commenter asserted that, because of the
uncertainty in the actual benefits (i.e., health and
environmental), an emission rate cutoff of 250 Mg/yr could
have been justified. This commenter stated that the data
necessary to adequately characterize the environmental
benefits of the proposed regulation should be collected prior
to setting an emission rate cutoff.
One industry commenter (IV-D-27 and IV-F-5) requested
that the EPA fully reevaluate the 150 Mg/yr cutoff after
correcting for a reported incorrect conversion factor and
recalculating the defaults.
Response: Prior to proposal, the EPA considered setting
a more stringent cutoff but concluded that the data available
at that time best supported the 150 Mg/yr level. As explained
in the proposal preamble, preliminary evaluations were
performed on several different emission rate cutoffs, ranging
from 25 to 500 Mg/yr. Three regulatory alternatives were then
chosen for more rigorous review: 25 Mg/yr (Alternative 1),
150 Mg/yr (Alternative 2), and 250 Mg/yr (Alternative 3) NMOC.
The alternatives provided the basis for the selection of BDT.
Based on consideration of the emission reduction
estimated at proposal and other factors specified in section
111 including health and environmental impacts, energy, and
klk-85\04 2-59
-------
cost, 150 Mg/yr of NMOC was proposed as the emission rate
cutoff in these regulations (56 FR 24468, May 30, 1991).
As a result of the changes in the data and methodology
for estimating emissions and costs for control of MSW landfill
emissions, and in the response to the public comments, the
regulatory alternatives and the estimates of the emission
• \
reductions and the control costs of alternative stringency
levels were revised after proposal. The changes in the data
and methodology for estimating emissions and costs are
described in the memoranda "Methodology Used to Revise the
Model Inputs in the Municipal Solid Waste Landfills Inputs
Databases" (Docket No. A-88-09, Item No. IV-M-4) and "Changes
to the Municipal Solid Waste Landfills Nationwide Impacts
Program Since Proposal" (Docket No. A-88-09, Item No. IV-M-3),
and were summarized in the supplemental notice of data
availability in the Federal Register (58 FR 33790,
June 21, 1993).
The proposal value of 150 Mg/yr is now estimated to
affect less than 2 percent of the landfills, obtaining only
45 percent NMOC and 24 percent methane emission reduction with
an average cost effectiveness of $800/Mg NMOC for new
landfills and $750/Mg NMOC for existing landfills. Therefore,
more stringent cutoffs were evaluated. At a cutoff of
50 Mg/yr, 5 percent of the landfills would install controls
with an NMOC reduction of 53 percent and a methane reduction
of 39 percent. The average cost effectiveness of this option
is $l,200/Mg NMOC for new and existing landfills. The
incremental cost effectiveness of going from a 150 Mg/yr
cutoff level to a 50 Mg/yr cutoff level is $2,900/Mg for new
landfills and $3,300 Mg for existing landfills. The
incremental cost effectiveness of cutoffs lower than 50 Mg, or
no cutoff would be unreasonable. Based on the revised impacts
analyses and the criteria for setting NSPS under section 111,
50 Mg/yr of NMOC was chosen as the emission rate cutoff.
kli-85\0* 2-60
-------
2.6.3 Requirements for Control Equipment
Comment; Two conunenters (IV-D-27, IV-D-41) requested
that testing requirements for enclosed flares be eliminated if
their design specifications report at least a 98-percent
destruction efficiency. One commenter (IV-D-41) stated that
both open and enclosed flares can achieve 98 percent
• %
efficiency, while the other commenter (IV-D-27) provided
additional emission information to demonstrate that enclosed
flares, when properly designed and operated, can meet
98-percent destruction efficiency. Two industry conunenters
(IV-D-27, IV-F-6) opposed the provisions for emission sampling
and testing for enclosed combustors (e.g., enclosed flares)
arguing that these flares are more efficient than open flares,
for which performance tests are not required. Another
commenter (IV-D-39) contended that the same testing be
required for all control devices, stating that it is not clear
why performance tests are not required for open flares. Two
commenters (IV-D-27 and IV-F-5, IV-D-39) also recommended that
a performance standard for enclosed flares be developed to
replace the testing requirements, while another commenter
(IV-D-41) requested that the design guidelines include
operating temperature, flow rate, and residence time for
enclosed flares.
Two conunenters (IV-D-19, IV-D-27) recommended that the
EPA identify both open and enclosed flares as BDT, and allow
owners and operators to choose between the two options.
Another commenter (IV-D-29) stated that their State requires
all new flares to be enclosed. The commenter suggested that
the regulations require that previously-installed open flares
be allowed to continue operation as long as they meet the
stated requirements. The commenter also suggested basing the
regulation on enclosed flares because they are more easily
tested, are quieter than open flares, and have no visible
light. Another commenter (IV-D-41) pointed out that open
flares present a visual nuisance.
kllc-85\0<. 2-61
-------
Response; The BDT for landfills is a collection system
and a combustion device. The combustion control device must
be capable of reducing NMOC emissions by 98 percent or to an
outlet concentration of 20 ppmv, dry basis, as hexane, at
3 percent oxygen. Both open flares and enclosed combustion
devices that achieve this performance level are BJDT and can be
used to meet the standards. Although performance testing is
the norm under section 111, it is impractical to require
testing of percent reduction from open flares, because outlet
concentration is infeasible to measure. The EPA developed
40 CFR 60.18 to address this problem. The provisions for open
flares in § 60.18 resulted from extensive testing by the EPA
demonstrating that properly operated open flares achieve
98 percent destruction efficiency. This testing would,
however, be too expensive for an individual owner or operator.
On the other hand, the performance testing for enclosed flares
and other enclosed combustion devices, is feasible. Thus, the
EPA considers required testing to be warranted for enclosed
flares consistent with the requirement for testing percent
reduction for other enclosed combustion devices, such as
incinerators.
States may impose additional requirements or restrictions
on the types of control devices used to address local concerns
such as noise and aesthetics. The fact that enclosed flares
are quieter and less visible does not mean that they provide
improved emission control over open flares.
Comment; One commenter (IV-D-37) requested that the EPA
explore the possibility of including NOX and CO limits in the
standards in order to reduce ozone formation and improve air
quality.
Response; The EPA appreciates the commenter's concern
about NOX and CO emissions from MSW landfills. In the
development of these standards, however, there were
insufficient data available for proposal of additional
standards for control of NOX and CO. Moreover, NOX and CO
concerns are addressed through the State Implementation Plans
klk-85\04 2-62
-------
(SIPs). States having NOX or CO concerns may address these
pollutants both through their SIPs and through establishing
more stringent standards for new sources under individual
State regulations.
Comment; One commenter (IV-D-38) stated that enclosed
combustors reaching the required 20 ppmvd of NMOC as hexane
may, in some cases, only meet a destruction efficiency of
93 percent or less, instead of the 98-percent reduction of
NMOC required in the proposed NSPS.
Response: The 20 ppmv alternative requirement to the
98-percent reduction of NMOC was established for the cases
where the initial NMOC concentration in the collected gas at
the combustor inlet is so low that demonstration of a
98-percent reduction would be infeasible. Thus, there are
times when less than 98 percent reduction is achieved, but
these are in cases where the inlet concentration is low and a
higher percent reduction is difficult to achieve. The
alternative is appropriate under the NSPS because technical
feasibility, cost, and demonstrated level of performance are
considered in the selection of BDT. While 98 percent
reduction cannot be demonstrated for all gas streams, 20 ppmvd
can be achieved.
Comment; Five commenters (IV-D-2, IV-D-18, IV-D-19,
IV-D-27, IV-D-29) addressed some aspect of I.e. engines. One
commenter (IV-D-18) agreed that if lean-burn I.e. engines are
to be used in nonattainment areas, they should be capable of
achieving a 98-percent destruction efficiency. One of the
commenters (IV-D-29) reported that I.e. engines having permit
conditions of 98-percent destruction efficiency had been
installed at local landfills, but they had not yet received
the compliance tests for review.
One commenter (IV-L-1) stated that the EPA should exclude
I.e. engines from those control devices deemed to be BDT and
adopt technology specific performance standards. The
commenter (IV-L-1) noted studies on landfill gas control
devices in Germany and Montgomery County, Maryland that
klk-85\0* 2-63
-------
reported the multipathway cancer risk associated with dioxin
emissions for a 1,500 ton per day landfill using an I.e.
engine were as much as 5 x 10""6. The commenter (IV-L-1)
stated that the risk for a landfill using a flare is
0.6 x 10~6.
The commenter (IV-L-1) also stated that the.California
Air Resources Board (CARB) has calculated NOX and CO emissions
from a 1,500 ton per day landfill using an I.e. engine to be
379 and 452 tons per year, respectively. The commenter noted
that these levels of emissions qualify these sources as major
under both PSD and nonattainment area new source review
regulations and that CARB has adopted rules limiting NOX and
CO emissions to 0.006 and 0.02 Ib/MMBtu for any treatment
system requiring 98 percent NMOC destruction.
Another commenter (IV-D-2) also did not support the use
of I.e. engines as a control device, and stated that I.e.
engines are not as efficient as other control devices and may
add to the formation of carcinogens.
One industry commenter (IV-D-27) reported that leanburn
I.e. engines are appropriate and capable of meeting the
98-percent destruction efficiency criteria on an average
basis. The commenter noted that the reduced load periods
reported as a concern in the preamble are unavoidable but
infrequent, and would not threaten achieving 98 percent
destruction on average. The commenter argued that lowering
the 98-percent destruction efficiency requirement would only
reduce the incentive for vendors to produce these engines with
that level of efficiency.
Response; The EPA selected a 98-percent reduction as the
level representing BDT for control because this is the level
achievable by demonstrated technologies. The EPA has
determined that this level is reasonable considering costs,
energy, and other environmental impacts. Thus, the
regulations will require all control devices to demonstrate
98 percent reduction or an outlet concentration of 20 ppmvd of
NMOC, as hexane. Commenters have not provided data showing
kl*-85\04 2-64
-------
that a lower performance level is appropriate for I.e.
engines.
Office of Research and Development (ORD) experts believe
that conditions for dioxin formation are not favorable. There
is very limited data available on this, and for studies such
as the German and Maryland ones mentioned in the commenter,
• %
the data have low quality assurance. After a review of the
information available, the EPA has determined that benefits of
LFG reduction far outweigh the uncertain concerns of secondary
pollutants generated. However, States that have concerns
regarding the use of I.e. engines can specifically disallow
them.
In the development of these standards, there were
insufficient data available for proposal of additional
standards for control of NOX and CO. States having NOX or.CO
concerns may address these pollutants both through their SIP
and through establishing more stringent standards for new
sources under individual State regulations.
Comment; One commenter (IV-L-6) was concerned that the
EPA had not acknowledged the role that air pollution control
costs for NOX emissions, especially in ozone nonattainment
areas, may play in the selection among flares, I.e. engines,
and turbines as the least cost option for control. The
commenter (IV-L-6) included NOX emission information for
flares, I.e. engines, and turbines. The commenter (IV-L-6)
requested that the EPA make sure that control systems are not
inappropriately subject to LAER and offset requirements
pursuant to the CAA.
Response: There are numerous factors that affect a
facility's decision on an appropriate control device for a
given landfill: ability to sell energy from energy recovery
devices, ability to switch control device during a landfills
history, community attitudes, financial restrictions, age of
the landfill, length of time control is necessary, attainment
status, location, etc. The least cost analysis was performed
on a nationwide basis as an indication of how many landfills
kUc-85\04 2-65
-------
might be able to use energy recovery as a savings on control
costs. It was not meant to be a landfill specific analysis
where all factors affecting the landfill were included. The
facility will have to consider many factors when selecting the
means of control for a given landfill including the attainment
status of their area. If LAER and offset requirements are
triggered by the emissions from the control device chosen, it
is appropriate that these requirements be met. It should also
be noted that controls added to comply with the landfills rule
may, at the discretion of the State, qualify for the pollution
control exemption from NSR.
Commenter: One commenter (IV-L-1) contended that
additional impacts from the purification of landfill gas are
not addressed in the proposed NSPS. The commenter contended
that emissions associated with any treatment or regeneration
of molecular sieves or other equipment employed to achieve
purification; and the need to control water quality impacts
from (a) the discharge of the blowdown and wastewaters from
both the purification and regeneration steps and (b) the
condensate removed from the gas collection systems should be
considered.
Response; The rule does not specify the types of control
devices that must be used, only that equipment achieve
98-percent reduction of NMOC or 20 ppmvd.
The nationwide impacts estimate considered the cost of a
flare for each landfill, which did not require costs of
purification. In the nationwide impacts estimate under the
energy recovery scenario, costs were included for filtering
the gas prior to an I.C. engine. The cost for handling
condensate removed from the gas collection system was also
included in the analysis; however, the rule does not specify
handling methods or techniques.
For further information on comments received on the
handling of gas condensate and the EPA's response see
section 2.16.3 "Subtitle D Interface" of this chapter.
klk-85\0* 2-66
-------
2.7 FORMAT OF THE STANDARD
Comment; One conunenter (IV-D-37) stated that the format
of their State regulation (California Model Regulation) for
measuring emission rates and determining whether controls are
required is simpler than the proposed regulation. In the
State regulation, any site with greater than 500,000 tons of
•«
waste must install gas collection systems, unless the owner or
operator can demonstrate there are only small amounts of
surface emissions. The conunenter suggested that no landfills
*
having less than 500,000 tons of waste-in-place would ever be
required to install controls under the proposed regulation
anyway.
One commenter (IV-D-26) stated that it would be easier to
use a total "tonnage in place" as a trigger to install active
gas extraction systems as opposed to the tiered approach. The
commenter contended that because of the conservative default
values, the Tier 1 calculation becomes academic and the
"tonnage in place" trigger would be a suitable alternative.
Response; The purpose of this regulation is to reduce
MSW landfill emissions or LFG, the designated pollutant.
Landfill gas is comprised of methane, CO2, and NMOC, and
emission rates of these compounds vary from
landfill-to-landfill, even when refuse in place (RIP) is
virtually identical.
Early in the development of these regulations, the EPA
proposed to base applicability of controls for MSW landfills
on RIP, and a RIP of 1 million Mg was selected. This format
was presented at the NAPCTAC meeting in May 1988. Both
NAPCTAC members and industry representatives advised that,
size and/or RIP were not sufficient basis for determining that
control or exemption from control is appropriate because of
variability of emission levels from landfill to landfill.
(See Docket No. A-88-09, Item No. II-B-15.)
As discussed in the proposal preamble under "Format for
Applicability," the EPA found that the NMOC emission rate
format achieved a greater emission reduction for lower costs
klk-85\04 2-67
-------
than a RIP format. The proposed NSPS combined a design
capacity exemption level of 100,000 Mg with an NMOC emission
rate trigger for control. The design capacity exemption was
reevaluated in the interim between proposal and promulgation
after review of additional data regarding gas generation
rates, and has been revised to 2.5 million Mg or
2.5 million m3. The revised cutoff would exempt approximately
90 percent of landfills from the testing and recordkeeping
required under the NSPS and EG, while only 15 percent of the
•
potential NMOC emission reductions would be lost.
Comment; Eight commenters (IV-D-25, IV-D-26, IV-D-31,
IV-D-34, IV-D-37, IV-D-39, IV-D-55, IV-F-4) supported a
performance based standard. Some of these same commenters
(IV-D-25, IV-D-26, IV-D-31, IV-D-34, IV-D-55) noted that
generated MSW gas does not equal emitted gas and indicated the
standard be based on measurement of gas emitted. One
commenter (IV-D-31) suggested the use of flux box testing or
monitoring concentrations of methane (as a surrogate for
NMOC).
Four commenters (IV-D-25, IV-D-34, IV-F-4, IV-D-55)
supported a performance standard based on TOC levels. The
commenters further suggested that the performance standard be
tailored after SCAQMD field monitoring based performance
standards, which specify that the maximum concentration of
methane at any point on the surface of the landfill cannot
exceed 500 ppmv, and that the average concentration cannot
exceed 50 ppmv. One commenter (IV-D-26) stated that the
California approved surface testing methods should be allowed
as a means to determine if controls are needed. Another
commenter (IV-D-55) also contended that because there is no
performance standard for the collection system, there is no
requirement to confirm that the collection system is
performing adequately. One commenter (IV-D-26) contended that
the EPA monitoring method for subsurface measurement of NMOC
is very costly and fails to focus on the true problem of
surface emissions of LFG and NMOC.
klk-85\0* 2-68
-------
One commenter (IV-D-37) discussed their State's
performance-based regulation for reduction of NMOC. This
regulation was based on actual landfill testing, which
revealed that at least one of the 10 air contaminants present
in LFG was found at 70 percent of landfills. Underground
migration of methane was a problem at 20 percent of the sites.
• %
Their state regulation differs from the proposed standard in
that it contains different provisions concerning which
landfills should be controlled, collection efficiency, and its
•
requirements for control system design, reporting,
recordkeeping and compliance. The commenter noted that
although the proposed regulations provide design flexibility
and encourage States to allow flexibility, their State's
regulation was simpler than the proposed standards.
Two commenters (IV-D-25, IV-D-34) asserted that the EPA
had not met its statutory obligation to demonstrate that it is
infeasible to set a performance standard prior to setting a
design standard for control of landfill emissions. The
commenter asserted that the performance-based SCAQMD landfill
regulation achieves 90 percent TOC destruction efficiency and
demonstrates that a performance standard is feasible.
One commenter (IV-D-39) suggested that a performance
standard based on an emission limit be proposed for
controlling air emissions at MSW landfills and that the method
of achieving the emission limit should not be specifically
addressed by the regulation. The commenter argued that by
establishing very specific design, operational and work
practice standards, the system will not function optimally and
cannot incorporate innovation in design. The commenter said
that an emission limit of 150 Mg/yr of NMOC alone will provide
the same level of environmental protection as the combined
design, equipment, and work practice standards, and allow
designers of LFG systems the flexibility needed to optimize
the design to fit the specific landfill situation.
klk-85\04 2-69
-------
The commenter also stated that the courts have expressed
a clear preference for the development of emission standards
as opposed to design, operational and work practice standards.
Another commenter (IV-D-55) noted that little if any NMOC
passes through the soil and that most of the emission release
points are through holes and channels. The commenter stated
• %
that with the notable exception of vinyl chloride and a few
other trace compounds, the primary source of NMOC is the
evaporative emissions of leachate. The commenter recommended
•
that leachate exposure be prohibited anywhere on the surface
of the landfill.
Response; A performance standard is not appropriate for
gas collection system design because it is not feasible to
measure gas generated versus gas collected at a landfill and
determine what performance a collection system is achieving.
Monitoring surface concentration alone also does not
demonstrate what fraction of gas is being collected or whether
the system is designed and performing optimally. However,
monitoring surface concentrations will indicate when cover
maintenance and well adjustments should be made as well as
when additional wells should be added. Surface monitoring
will also provide a safeguard against uncertainties in area of
influence determinations. Surface emission monitoring is
discussed in section 2.12.1 of this chapter.
Because a performance standard is not feasible, a
design and operational standard has been set as BDT for gas
collection system design. The specifications for active
collection systems do not give prescriptive design
specifications; rather, they present criteria on which to base
a collection design plan. All owners or operators must submit
their collection system design plan to the Administrator for
approval. The purpose of collection and control equipment is
to capture and control gas generated within the landfill. The
collection system must be installed within 1-1/2 years of the
design plan submittal or notification of intent to install.
In addition to the criteria in S 60.759, the collection system
kUc-85\04 2-70
-------
must also meet the four criteria specified in
S 60.752(b)(2)(ii), which states that: (1) the collection
system design plan must be prepared by a professional
engineer, and designed to handle the maximum expected gas flow
rate over the intended equipment use period, (2) gas must be
collected from all active areas in the landfill in which
• %
refuse is more than 5 years old, and from all closed areas (or
areas at final grade) in which refuse is more than 2 years
old, (3) gas must be collected at a sufficient extraction
*
rate, and (4) the collection system must be designed to
minimize off-site migration of subsurface gas.
As discussed in the preamble to the proposal (see
56 FR 24484; May 31, 1991), to establish an emission limit or
performance standard for collection, the exact quantity of gas
being generated by each area of the landfill would need to.be
quantified, and then the reductions achieved would need to be
compared to it. This is technically infeasible. Estimates
vary regarding the actual percentage of produced gas that can
be collected, anywhere from 50 to 90 percent, but the EPA and
industry alike recognize that these are only estimates.
Therefore, design and operational standards were set for the
collection system.
A performance standard was, however, set for the control
device, because once the gas has been collected, the
destruction efficiency of the control device can be
established. Landfill owners or operators using the SCAQMD
approach can submit designs to the State as provided in
40 CFR 60.752(b)(2) or 40 CFR 60.33c(b). The regulations
allow the flexibility to use alternative gas collection and
control systems as long as they are demonstrated to be as
effective as a system designed to meet the criteria in
S 60.759. [See 40 CFR 60.752(b)(2)(i)].
In response to commenters who indicated that gas emitted
was not equal to gas generated, as explained in the proposal,
the NSPS and emission guidelines address all of the MSW
landfill emissions generated within the landfill, and not just
kli-85\04 2-71
-------
those emitted through the cover. The NMOC can be emitted in
several ways: through the landfill cover, through holes and
channels, through evaporation of leachate, or through
underground offsite migration through the soil. The EPA
considers the primary source of NMOC emissions to result from
transport and stripping by methane-laden gas as it migrates
• *
through the soil/refuse. Diffusion and displacement are also
transport mechanisms that impact the NMOC emission rate. No
matter how the NMOC migrates to the atmosphere, a
•
well-designed gas collection system will minimize the
potential for NMOC emissions with the most confidence.
The commenter (IV-D-55) did not provide documentation on
the evaporative emissions from leachate and its contribution
to NMOC emissions. Leachate on the landfill surface is
addressed under RCRA.
2.8 NATIONWIDE IMPACTS
Comment; One commenter (IV-D-17) suggested that the
proposed emission estimates may lack accuracy because of
variations in the types of waste that landfills accept and the
limited availability of records estimating the decomposable
amounts of waste. A second commenter (IV-D-55) was concerned
that the estimated potential reductions are overstated and are
in conflict with CARB estimates, the EPA's own emissions
inventory factors (Procedures for the Preparation of Emission
Inventories for Precursors of Ozone, EPA-450/4-88-021,
p. 4-31), and district field data. The commenter recommended
that the calculated NMOC emission reductions should be
confirmed and resolved with other conflicting emission
estimates. The commenter also suggested that this data be
published and submitted for public comment before the data is
used.
Response; The nationwide impacts were developed using
data from the OSW landfill survey, which provided information
from a large number of landfills; information about NMOC
concentration and methane generation from section 114
responses and industry submittals; and additional EPA studies.
klk-65\0* 2-72
-------
The information from the OSW survey consisted of landfill
location, annual waste acceptance rate, refuse in place in
1987, age, depth and design capacity for 931 landfills. The
information on NMOC concentration and methane generation used
at proposal was randomly assigned to the landfills from the
OSW survey because this information was not included in the
survey. This additional information was randomly assigned in
order to represent the variability reported by industry, and
referred to by the first commenter.
*
In the interim between proposal and promulgation of these
regulations, additional NMOC concentration and methane
generation data were obtained, and the methodology for
randomly assigning the data to the landfills from the OSW
survey was revised. These changes are described in the
memorandum "Methodology Used to Revise the Model Inputs in the
Municipal Solid Waste Landfills Input Data Bases (Revised)"
(Docket No. A-88-09, Item No. IV-M-4). The EPA considers the
large database of landfills and the assignment of Lo and CNMQC
values to reasonably represent the variability among landfills
in the U.S. This methodology best represents the variability
reported for landfills. If an emission factor method had been
used, variations in waste composition, age, landfill
geography, etc., would have no opportunity to impact the
results.
The NMOC emissions reductions were estimated by the EPA
using a modification of the Scholl Canyon model and a range of
NMOC values obtained from test data. Because of the change in
emissions over time and the varying emission levels from
landfill to landfill, nationwide emissions and emissions
reductions are best described in terms of NPV. This approach
accounts for the variations noted and presents the emissions
on a normalized basis for comparison between different
emission rate cutoffs. The emissions estimates calculated
using the commenter's data would result in annual emissions,
which cannot be compared to the net present value.
Furthermore, the EPA's approach accounts for the emissions
klk-85\04 2-73
-------
resulting from each subpart of mass at various ages, while the
emission inventory factor is constant and would overestimate
emissions when used with net present value calculations.
One commenter (IV-D-26) submitted test data on
NMOC concentrations ranging from 300 to 7,500 ppmv.
Response ; All values for which the EPA had adequate
documentation were used in estimating national impacts of the
NSPS and EG. Some of the NMOC concentrations submitted by
commenter IV-D-26 were sufficiently documented to be included
•
in the data bases. However, the NMOC concentrations for use
in the nationwide impacts were reevaluated and assigned to the
input data bases before the values provided by the commenter
were received. The values submitted by commenter IV-D-26 fit
within the revised range of NMOC concentrations used in
developing the final nationwide impacts. The EPA determined
that incorporating the NMOC concentrations provided by the
commenter would not significantly change the estimated impacts
of the regulations, and, therefore, additional resources were
not expended to incorporate the additional concentrations into
the data bases.
Comment ; One commenter (IV-D-22) suggested that the EPA
further investigate the effects of moisture on methane
generation. The commenter proposed evaluating the effect
capping with a geomembrane would have on the moisture content,
as well as the methane generation rate.
Response; The EPA considered such variability in
moisture content early in the development of these
regulations. However, moisture content varies based on
geography, topography, and even management practices, such as
cover types and maintenance procedures. Although it is
infeasible to incorporate all these site-specific factors in
the model, the impacts of these factors would be accounted for
if gas production testing were performed at the landfill, as
in Method 2E, or NMOC concentration was measured, as in
Method 25C. The EPA acknowledges that the use of a
geomembrane or other effective cover will reduce moisture
klk-85\04 2-74
-------
content to some degree. However, at this time the impact of
the use of a geomembrane is unknown, and therefore, was not
included in the model.
During the interim between proposal and promulgation of
these regulations, the EPA incorporated location within an
arid or nonarid region in the analysis. The site-specific
• %
methane generation data were categorized as arid or moist
based on the location of the landfill from which the data were
generated. The methane generation data were assigned to the
•
input data bases in proportions to represent the amount of
waste and the number of landfills located in arid and moist
regions of the United states. This methodology is described
in the memorandum "Methodology Used to Revise the Model Inputs
in the Municipal Solid Waste Landfills input Data Bases
(Revised)" (Docket No. A-88-09, Item No. IV-M-4).
Comment: One industry commenter (IV-D-27) contended that
the EPA overestimated the number of new MSW landfills opening
in the first 5 years of the regulations, and that this number
will be smaller because of the combined impact of the proposed
regulations, new subtitle D regulations, transport
restrictions, waste reduction and recycling programs, and the
NIMBY syndrome. The commenter criticized the Agency
assumption that existing landfills would be replaced with new
landfills having similar characteristics as they closed,
noting that the State of the art of landfill design, and
growing State and Federal restrictions would result in
"different" landfills.
Another commenter (IV-D-39 and IV-F-3) stated that more
landfills will actually be affected than the EPA had stated,
because there are now approximately 7,500 landfills instead of
the 6,000 that the EPA reported to exist in 1987.
Response; The EPA is not certain that fewer landfills
will be opened. It is precisely this inability to predict the
exact characteristics of future landfills that led to the
decision to model new landfills based on the current
characteristics of landfills. If fewer landfills will be
kUc-85\04 2-75
-------
opened, these landfills may be larger, resulting in a lower
costs per Mg of emission reduction.
To estimate the impacts of the regulation through 1997,
the EPA modeled landfills opening after 1987 based on the
population of landfills in 1987. The EPA estimates that
approximately 7,440 landfills existed in 1992, which
' *
corresponds to the estimate of 7,500 provided by the
commenter.
2.8.1 Cost Impacts
Comment; Several commenters (IV-D-39 and IV-F-3,
IV-D-46, IV-D-55, IV-F-4) stated that the EPA underestimated
costs for gas collection systems. One commenter (IV-F-4)
contended that the underestimation resulted from the analysis
being based on large landfills. The commenter asserted that
the uncertain service life of system components may contribute
to additional nationwide costs. Another commenter (IV-D-39
and IV-F-3) stated that the underestimation resulted from
incomplete data. Other commenters (IV-D-55, IV-F-4) argued
that the design specifications and proposed method for well
spacing would increase the program costs without added
benefit.
One commenter (IV-F-5) stated that the cost of many of
the monitoring provisions, such as temperature indicators,
flow indicators, heat sensing devices, pilot flame indicators,
and wellhead pressure gauges, may be too burdensome.
One commenter (IV-D-53) stated that small landfills are
experiencing financial hardships due to the increasing number
of new landfill regulations. The commenter was opposed to any
regulations that are extremely costly or technically unsound.
One commenter (IV-D-52) expressed concern for taxpayers
who are constantly being asked to pay for new regulations.
The commenter suggested that the proposed regulations should
focus on using control methods already in practice at larger
facilities.
Two commenters (IV-D-25, IV-D-34) reported that
preliminary information from the SWANA survey of selected
kLk-85\04 2-76
-------
collection system owners and operators indicated that the
EPA's cost projections were too low due to underestimating
system capital and operational and maintenance costs. The
commenters further argued that because the modeling
assumptions result in inflated emission rates, the cost
effectiveness of the standard is also skewed. One of the
'»
commenters (IV-D-25) noted that all of the data received in
response to the survey would be reviewed and submitted for
Agency review. (These surveys, along with a cost analysis,
•
were submitted to the EPA and reviewed. See Response for
details.)
Response; The cost impacts were determined using data
from the OSW data base, section 114 responses, industry
information voluntarily submitted over the course of
regulatory development, and standard engineering sources. .The
collection system design for the proposed regulations was
similar to systems in place at many landfill sites, and
information on component design included data gathered both
from collection system operators and vendors. The cost basis
for the proposed regulations were presented in chapter 7 of
the proposal BID. However, to provide flexibility and reduce
costs, the EPA removed the prescriptive design specifications
for gas collection systems and replaced them with design
criteria. This allows owners and operators to design the most
cost-effective gas collection system (meeting certain minimum
requirements) for their landfill.
As stated in the proposal BID, the OSW data base, which
made up the overall structure of the data base used for the
cost impacts, included 151 large landfills and 780 small
landfills. The EPA is satisfied that large landfills were not
over represented.
Nationwide control costs were developed by designing and
costing a control system for each landfill in the data base,
and these costs were determined to be reasonable for most
landfills which would require control at the proposed
regulatory emission rate cutoffs. Also, the design capacity
klk-85\04 2-77
-------
exemption was reevaluated in the interim between proposal and
promulgation, and has been revised to 2.5 million Mg.
Landfills with a design capacity less than 2.5 million Mg will
not be affected by the final regulations. Therefore, small
landfills will not be adversely impacted by the regulation.
Both collection and control system design and costing
• x
were developed with a high level of industry participation
(see Docket A-88-09, categories II-C and II-D). The service
lives of blowers, motors, turbines, and flares were considered
in the proposal and promulgation cost impacts analysis.
Consideration of I.e. engine and well service lives were added
to the promulgation cost impacts analysis. The final cost
analysis presents a reasonable estime on of cost impacts that
are to be representative of both large and small landfills.
The monitoring provisions in the final standards are
typical of monitoring provisions under the NSPS program for
similar control equipment, and are necessary to ensure proper
operation of the equipment, and to avoid fire or explosion
hazard. However, since proposal the EPA has provided for the
option of monitoring of bypass systems rather than monitoring
flow to a control device. The use of flow indicators in
bypass lines or the use of bypass systems with car-seals, lock
and keys, or other configurations that provide a record of
bypass system use may reduce the monitoring burden associated
with the monitoring of flow to the control equipment. The EPA
determined that the monitoring costs of the final regulations
were reasonable and necessary to ensure proper operation of
collection and control equipment.
The EPA received and reviewed the SWANA survey and
associated cost analysis. The EPA cost numbers, at first
review, appear lower than the survey results. However, the
costs analyses presented in the proposal BID were based on
equipment costs in 1987 dollars, several years before the
SWANA survey was conducted. Also, the EPA cost impacts
analysis at proposal was a rigorous two-stage time accounting
of dollars in 1992 NPV. The SWANA cost analysis is a
klk-85\0* 2-78
-------
summation of dollars expressed in varying years. If the SWANA
data were in a form which could be utilized in its nationwide
impacts model, the results would not differ significantly.
The EPA considers that the information provided by
respondents to the EPA's section 114 information requests was
accurate, and was generally provided in direct response to
• %
specific questions. The SWANA survey was not conducted under
such rigorous conditions or requirements, and consequently did
not provide as specific a system or cost breakdown.
•
Additionally, the SWANA costing survey compiled answers from
only 13 actual landfill collection systems, managed by five
individuals or organizations and, therefore, did not represent
a large increase in information. However, The EPA did utilize
the results of the SWANA survey wherever possible, such as in
developing time frames for system component replacement.
Comment; One commenter (IV-L-3) maintained that cost
information is readily available only from certain vendors and
major gas system developers. The commenter (IV-L-3) was
concerned that the cost information used in the development of
the regulations is not representative, particularly for
smaller developers. The commenter (IV-L-3) maintained that
small developers will not enjoy economies of scale and
recommended that the cost analysis account for varying
economies of scale for equipment purchases and operation and
maintenance services.
The commenter (IV-L-3) cited the EPA report, "Landfill
Gas Energy Uses: Technology Options and Case Studies." The
commenter (IV-L-3) stated that this report shows 1992 median
I.e. engine costs of about $1,300 per kilowatt. The commenter
(IV-L-3) also cited a George Jansen, of Laidlaw, report, "The
Economics of Landfill Gas Projects in the United States"
presented in Australia in February of 1992. The commenter
(IV-L-3) stated that this report estimated I.e. engine system
costs of $1,500 per kilowatt. The commenter (IV-L-3)
contended that when the economy improves, the costs of
installation for electrical projects may increase towards a
kli-85\04 2-79
-------
value of $1,200 to $1,500 per Kilowatt of installed capacity,
not the $1,000 we see today. The commenter (IV-L-3) stated
that the Jansen report has good cost insights which should be
more representative of an average economy.
The conmenter (IV-L-3) also listed other factors and
obstacles that make capital and operations costs higher,
• x
including distance from transmission lines, difficulty in
getting needed water, and difficulty with permitting. The
commenter (IV-L-3) recommended that the EPA reexamine the
various gas to energy implementation and operational costs.
Response; The cost figures were meant to be an average
cost that could be applied to various energy recovery projects
across the Nation, in order to develop nationwide cost
estimates. It is true that small developers may have to pay a
higher fee than larger developers, and some developers will
pay a lower fee because of their location. The EPA does not
contend that all developers will pay the same price, but does
consider the costs applied to be average costs suitable for
nationwide impacts estimates.
The costs that were used for I.e. engines were based on
information from two I.e. engine vendors and a vendor-referred
contractor. These vendors supply many of the I.e. engines
used for landfill gas combustion. The calls collecting the
data were made in early 1992. At this time, neither the EPA
report or the George Jansen report were available to the EPA.
The EPA used the best data available at the time. In
addition, the I.e. engine cost used in the nationwide impacts
analysis is still within the range of the I.e. engine costs
predicted by the EPA report. The EPA report cites I.e. engine
costs in the range of $1,000 to $2,500/kW with lower costs for
smaller I.e. engines and used equipment.
The commenter also showed their agreement for the
$l,000/kw figure by stating that the $l,000/kw is the price
seen today, and that the cost of I.e. engines will increase to
$1,200 to $l,500/kW when the economy improves. It is true
that the costs may change with the change in economic factors,
klk-85\04 2-80
-------
however, the purpose of this analysis was to acquire a
reasonable estimate of cost and then determine the nationwide
impacts. The effect of many factors on the operation and
capital costs of control equipment cannot be predicted
especially considering the schedule and resources available to
the EPA. These factors include distance from transmission
lines, availability of water resources, and permitting issues.
Two cominenters (IV-D-21, IV-D-33) suggested
that the cost analysis be revised to incorporate the role of
energy recovery.
Response; In response to these and other comments
indicating that the likely use of energy recovery should be
incorporated in the nationwide impacts and analysis, the
nationwide impacts were revised to include a more detailed
review of energy recovery prior to promulgation of the final
NSPS and EG. See section 2.8.3, Cost-Benefit Analysis, for a
detailed discussion of the revised analysis.
Comment ; One commenter (IV-L-7) objected to the EPA's
decision to delete the 138 most profitable landfills from the
nationwide impacts. The commenter (IV-L-7) contended that
there is no basis on which to exclude the data on the best
(most productive) landfills in a way that hurts the
cost/benefit analysis of such regulatory measures. The
commenter (IV-L-7) noted that information given in the
memoranda, "Changes to the Municipal Solid Waste Landfills
Nationwide Impacts Program Since Proposal, " April 28, 1993,
(Docket No. A-88-09, Item No. IV-M-3) and "Landfill Rule
Energy Recovery Cost Analysis," December 16, 1992, (Docket
No. A-88-09, Item No. IV-M-2) indicated that many sites will
not install energy recovery equipment in absence of these
rules; and that new landfill rules in California have caused
many sites to install energy recovery equipment in order to
comply with the new rule. The commenter (IV-L-7) stated that
these rules will force the development of new technologies and
landfill gas recovery vendor services that will transform the
klk-85\04 2-81
-------
market, which will decrease up front installation costs and
increase efficiency.
Response; The EPA agrees with the commenter that the
landfill gas market will be transformed by new rules forcing
the development of new technologies and landfill gas recovery
vendor services. This was a main reason the least cost
• x
analysis option was developed; in order for the standard to
"take credit11 for the positive changes to the landfill gas
market and the increased use of energy recovery technology
which the standard will generate. There are several
site-specific reasons that influence the choice of whether to
recover energy: financial limitations (there is a large
initial investment), ability to sell the energy, the risk
factor (it is difficult to predict the productivity of a
landfill), etc. The standard should influence these factors
and make it favorable for landfill owners or operators to
choose energy recovery. However, there are landfills that
have energy recovery systems and some future landfills that
will potentially have energy recovery systems in the absence
of this standard. The adjustment of deleting the 138
landfills was made so as not to "take credit" for those
landfills that would recover energy from landfill gas without
the influence of this standard. The 138 landfills estimated
to install control in the absence of the standard is based on
past numbers of landfills installing energy recovery and
projecting into the future. More information may be found in
the memorandum "Landfill Rule Energy Recovery Cost Analysis,"
December 16, 1992 (Docket No. A-88-09, Item No. IV-M-2).
As this commenter has stated, when the NSPS and EG go
into affect it is likely that more landfills will choose
energy recovery which will have an affect on the market and
the up front installation costs. However, the nationwide
impacts are correctly based on current information. The CAA
requires periodic reviews of NSPS. Advances in energy
recovery may be considered in the periodic reviews of this
NSPS.
klk-85\0* 2-82
-------
2.8.2 Secondary Air Impacts
Comment; One commenter (IV-D-20) suggested that the EPA
has not thoroughly assessed secondary air pollutant emissions
impacts from open flares. The commenter questioned whether
open flare control devices are BDT and stated that the
proposal BID contains little information on secondary air
• \
pollutant emissions from open flares. The commenter
recommended that enclosed flares be chosen as BDT if further
evaluation demonstrates that open flares have higher levels of
•
secondary air emissions than enclosed flares.
Another commenter (IV-D-17) recommended that the
occurrence of PICs from open flares be addressed (references
to combustion data were included). The commenter stated that
PCDD might be produced by combustion of NMOC, and suggested
that the occurrence or lack of occurrence of PCDD must be
addressed before combustion can be classified as BDT.
The commenter (IV-D-17) indicated that flare combustion
analysis should be required and should incorporate the percent
of chlorine in LFG, flare operating conditions (i.e.,
temperature, residence time, POHC, PIC (PCDD/PCDF, etc.), and
risk assessment. For risk assessment, the commenter indicated
that the normalized distribution for an emissions source of
1 gram/sec with a dilution factor of 1 to 10 km should be
supplied.
Response; Open flares have already been established as
an appropriate control technology under section 111. Open
flares are suitable for LFG if they meet the provisions under
40 CFR 60.18, as discussed under section 2.6.3. The EPA knows
of no data that indicates that open flares have higher
secondary emissions than other combustion devices.
The EPA has already determined under previous projects
that flares operated according to section 40 CFR 60.18 will
achieve greater than 98 percent organics destruction. The
available data considered by the EPA, while indicating the
presence of PCDD precursors in landfill gas, does not indicate
PCDD precursors after combustion in flares.
2-83
-------
Comment; One commenter (IV-D-50) said that the proposed
regulation appears to underestimate secondary emissions from
LFG combustion, and challenged the assumption that
LFG-generated electricity would likely replace coal-fired
generation. The commenter cautioned that previous EPA studies
showed that energy recovery systems can result in a more
* *
expensive and less efficient source of energy due to higher
secondary air emissions from energy recovery systems fueled
with LFG and reduced thermal efficiency compared to natural
*
gas-fired generation.
Response; The EPA assumes that market forces govern the
purchase of LFG-generated electricity. The proposal BID
discussion of secondary impacts assumed that a utility
purchasing LFG-generated electricity would replace the most
expensive electricity being purchased, which, at that time was
usually coal-fired, not natural gas-fired, generation. Since
coal-fired generation is more costly and has greater secondary
air impacts than LFG generation, LFG-generated electricity
would reduce secondary air impacts from electricity
generation. The EPA reviewed the references provided by the
commenter, but found no data included specific to LFG. It
must be noted that no quantitative adjustment to the secondary
air impact tables in chapter 6.0 of the proposal BID was made.
The EPA made only a qualitative judgment about secondary air
impacts of LFG-versus coal-generated electricity. Information
on LFG-generated electricity programs and the estimated
impacts of the LFG-versus coal-generated electricity is
presented in the memorandum "Analysis on Landfill Gas
Utilization of the Soon-to-be Promulgated Clean Air Act
Regulations for Municipal Solid Waste Landfills" (Docket
No. A-88-09, Item No. IV-B-5).
Comment; One commenter (IV-D-19) noted that turbines,
boilers, and I.e. engines tend to have much higher NOX
emissions than flares. In addition, I.e. engines have higher
CO emissions, while boilers and turbines have lower CO
emissions than flares.
klk-85\04 2-84
-------
Response; The goal of the regulation is to reduce the
amount of LFG emitted to the atmosphere. If a State has
specific concerns regarding NOX or CO, they may implement
additional or more stringent regulations to address these
concerns.
The EPA data does indicate greater NOX emissions from
turbines, boilers, and I.e. engines than flares. However,
this fact may be offset by the fact that these devices can
recover energy from LFG. Energy recovery will have benefits
of conserving the nation's supply of nonrenewable energy
resources and will decrease pollution from the energy
generation displaced by the use of these devices. These
benefits are discussed in chapter 6 of the proposal BID, as
well as in the proposal preamble (56 FR 24498; May 30, 1991).
2.8.3 Cost-Benefit Analysis
Comment; One commenter (IV-F-6) questioned whether the
costs of the regulation are equal to the health improvements.
The commenter claimed that there has been no analysis of
potential benefits of the regulation and that only the
threshold levels and control options have been considered in
the rulemaking. Another commenter (IV-D-39) asserted that
sufficient justification for the standards has not been
provided on the basis of cost effectiveness and environmental
benefits. A third commenter (IV-F-3) said that the data used
in the RIA concerning the cost effectiveness and environmental
benefits of the regulation were incomplete.
Response; Section lll(b) of the CAA addresses categories
of sources which cause, or contribute significantly to air
pollution, which may reasonably be anticipated to endanger
public health or welfare. The NSPS are technology-based,
rather than risk-based, standards. As stated in the preamble
under this NSPS, MSW landfill emissions must be controlled to
the level achievable by BDT, considering costs and any nonair
quality health and environmental impacts and energy
requirements. The NSPS are not primarily concerned with
quantifying health improvements, as are NESHAP.
klk-85\04 2-85
-------
As explained in the preamble, the BDT was selected based
on consideration of the costs and emissions reduction achieved
by the regulatory alternatives as provided in section lll(b)
of the CAA.
Comment; One commenter (IV-D-36) stressed that the high
costs incurred from addressing the small percentage of methane
emissions derived from MSW landfills were not justified.
Another commenter (IV-D-11) indicated that public utilities
should excuse methane generated fuel cell power from
least-cost regulations because of the social benefits gained
from this clean fuel source.
Response: The selection of the NSPS and EG was not
determined by the cost of methane reduction. Methane
reduction was considered as an ancillary benefit. Nationwide
annualized costs were estimated for new and existing MSW
landfills to be approximately $4 and $90 million,
respectively. The average cost effectiveness of the NSPS and
EG are $1,200 per Mg of NMOC emission reduction. The
incremental cost effectiveness of going from a 150 Mg/yr
emission rate cutoff to a 50 Mg/yr cutoff is $2,900/Mg for new
landfills and $3,300/Mg for existing landfills. The standards
address MSW landfill emissions in a cost effective manner.
The EPA is investigating fuel cells; however, the
investigation is not complete to incorporate at this time.
Additionally, the decision to require public utilities to deal
with fuel-cell generated methane in a prescribed manner is
beyond section 111 Authority.
Comment; One commenter (IV-D-50) noted that the proposal
BID lacks correct information regarding costs of energy
recovery systems because it does not include discussion of a
backup flare system and system availability and reliability.
Response; The cost impacts of these regulations were
calculated based on the use of flares and on the use of least
cost devices (including energy recovery). Although the EPA is
aware that many operators do maintain backup flares on site,
they are not required in the NSPS and EG. Operators may
klk-85\04 2-86
-------
determine on a site-specific basis whether to install a back-
up device. In many cases control devices may be reliable
enough that a back-up is not needed, especially considering
that the NSPS emission standards do not apply during periods
of malfunction. Additionally, when a backup flare is
installed, it would likely last indefinitely and contribute
relatively little to the overall cost of compliance with the
standard.
In regard to system availability and reliability, the
proposal BID did not attempt to provide exhaustive information
regarding energy recovery systems, specifically because of the
site-specific nature of factors influencing energy recovery
selection decisions. The proposal BID and subsequent analyses
reasonably represent energy recovery system costs, however
these costs are greatly affected by site-specific factors,
which are best addressed by the MSW landfill owner or operator
when the use of energy recovery is considered.
2.9 MONITORING AND TESTING
2.9.1 Monitoring
Comment; One commenter (IV-L-1) recommended that the
NSPS require the measurement of landfill gas emissions from
collection systems and/or control devices on a real time basis
using continuous emissions monitoring instrumentation rather
than annually performing manual measurements such as
Method 25C.
Response: In selecting measurement methods for measuring
LFG emissions, the EPA selected methods that were simple, yet
would provide information adequate for establishing
compliance. Other methods may be used if they have been
approved by the Administrator.
The final rule also requires surface emission monitoring
of landfills on a quarterly basis to confirm correct system
operation. Surface emission monitoring will ensure that
landfill gas control systems are operating adequately and that
no significant emissions are escaping from the landfill
surface. For control devices, continuous monitoring of
kLk-85\04 2-87
-------
operating parameters is required. The EPA will not require
continuous emissions monitoring instrumentation when other
less expensive methods are available that are appropriate for
establishing compliance.
Comment; Two commenters (IV-D-27, IV-D-39) asserted that
the requirement to monitor residence time during.the initial
performance test cannot be met, because residence times for
control devices can only be calculated and cannot be
monitored.
Response; The compliance provisions of the final NSPS
(§ 60.755) are based on typical section 111 provisions for
open flares and enclosed combustion devices. The intent of
this section of the regulation is to require that residence
time be determined during the initial performance test for
enclosed combustion devices. The final regulation was changed
to reflect that residence time should be determined in
conjunction with gas flow measurements and temperature rather
than "monitored." After the initial performance test, the
NSPS only requires that temperature be recorded with equipment
calibrated, maintained, and operated according to the
manufacturer's specifications. Flow to the control device
must be monitored, or else bypass line flow can be monitored
or bypass lines can be sealed to prevent bypass.
Comment; Two industry commenters (IV-D-27, IV-D-39)
recommended that monitoring temperature not be limited to
Celsius units of measure, since most devices are provided with
Fahrenheit units.
Response; Current policy is to use metric units in
reporting; however, this does not preclude measuring in
English units. The following equation can be used for
converting degrees Fahrenheit to degrees Celsius:
°C - (°F - 32)/1.8.
Comment: One industry commenter (IV-D-27) suggested that
the provisions for monitoring temperature at enclosed flares
be changed to require monitoring "at least every 15 minutes"
kUc-85\OA 2-88
-------
rather than "every 15 minutes" to increase flexibility in how
this requirement is met.
One commenter (IV-D-39) asserted that requiring a flow
indicator that provides a record of gas flow at intervals of
every 15 minutes is an unnecessary and expensive method to
collect the required data. The commenter recommended that
• %
this requirement be replaced with the requirement that the
owner or operator simply record flow at 15 minute intervals,
which would allow for other methods of obtaining the data
without requiring a specific type of equipment.
Response; The provisions for monitoring temperature of
an enclosed combustion device have been revised. The final
provisions require a temperature monitoring device equipped
with a continuous recorder and having an accuracy of
± 1 percent of the temperature being measured expressed in.
degrees Celsius or + 0.5°C whichever is greater. Records must
be made at least every 15 minutes. Also, the requirement of
using a flow indicator that provides a record of gas flow at
intervals of every 15 minutes has been changed to requiring a
gas flow measuring device that provides a measurement of gas
flow to, or bypass of, the control device. If gas flow is
monitored, the gas flow rate must be recorded at least every
15 minutes. Alternatively, a bypass system that has either a
car-seal, lock and key, or other device that reveals if the
bypass system has been used can be installed instead of
monitoring flow.
Comment: Two commenters (IV-D-26 and IV-F-6, IV-D-27)
recommended that the flare flame rather than the pilot flame
be monitored to verify that the flare is operating at all
times. One of the commenters (IV-F-6) stated that MSW
landfills that have flares typically use intermittent pilots
to conserve propane. The commenter stated that continuous
pilots are costly, inefficient, and unsafe. One of the
commenters (IV-D-27) opposed the stringent provisions for
monitoring flow to the flare or other control device,
reporting that such equipment could cost from $4,000 to
kli-85\0* 2-89
-------
$12,000. The commenter proposed that a monthly measure of
flow at the flare using various devices (e.g., pitot tube,
orifice plate, etc.), along with continuous flame temperature
monitoring, would be sufficient to catch any major changes in
flow.
Response; The monitoring provisions of S 60*756 were
revised to allow for continuous monitoring of flow to the
flare pilot flame or the flare flame itself. An intermittent
pilot would not meet this requirement because it could not be
continuously monitored. If direct monitoring of the flare
flame is not feasible because the temperature of the flare
flame is too high and will cause the thermocouple of the
monitoring device to burn out more quickly than if the pilot
is monitored, the source may chose to monitor the pilot flame.
The requirement to monitor flow to the flare or other control
device at least every 15 minutes was intended to ensure that
the collected landfill gas is being conveyed to a flare, or
other suitable control device, rather than being discharged to
the atmosphere. The regulation has been changed since
proposal to allow the alternatives of monitoring flow in each
bypass line, or sealing bypass lines with car-seals or lock
and key configurations that prevent bypass and reveal whether
bypass has occurred. This will allow flexibility and reduce
costs. Other comments and responses pertaining to open flames
are contained in 2.8.2 of this chapter.
2.9.2 Nitrogen Monitoring
Comment: Many commenters (IV-D-7, IV-D-26 and IV-F-6,
IV-D-27, IV-D-35, IV-D-39, IV-D-55, IV-F-4, IV-L-5) contended
that the 1 percent N2 limit in the proposed standard is
unrealistic, and that levels of 11 (IV-D-35), 12 (IV-D-27),
20 to 25 (IV-D-26 and IV-F-6) and no less than 6 percent
(IV-D-39) are more appropriate. One commenter (IV-D-39) also
reported that successful operation has been shown at levels as
high as 20 percent. Three of the commenters (IV-D-7, IV-D-25
and IV-F-4, IV-D-34) recommended dropping the N2 limit
altogether. Two commenters (IV-D-25 and IV-F-4, IV-D-34)
kli-85\04 2-90
-------
stated that the requirement restricts operators in maximizing
vacuum levels. One commenter (IV-D-7) stated that setting the
limit based on combustibility had no engineering basis.
Another commenter (IV-D-39) also asserted that the 2 percent
N2 limit in the collection header is too stringent.
Several commenters (IV-D-26, IV-D-35, IV-D-39, IV-D-55)
•»
discussed the N2 content of landfills. The commenters stated
that N2 levels of 7 to 8 percent (IV-D-35), 5 percent
(IV-D-39, IV-D-55) and between 1 and 4 percent (IV-D-26) are
•
common. One commenter (IV-D-55) stated that Figure 3-3 of the
proposal BID indicates that the N2 content of landfills levels
out at 5 percent. Another commenter (IV-D-39) referenced a
document by EMCON Associates, "Methane Generation and Recovery
from Landfills", as the source for the 5 percent N2 level.
The commenter also reported that the EMCON Associates document
states that N2 is expected to peak just after placement of
refuse, and will then fall dramatically as the refuse begins
to decay to the 5-percent steady state level. The commenters
stated that the N2 content was due to trapped air buried at
the time of filling the landfill (IV-D-26) and/or is released
from the refuse (IV-D-39). Another commenter (IV-D-3)
suggested that it would be difficult to determine if the N2
came from buried nitrogen or improper sampling.
One commenter (IV-D-39) suggested the EPA develop a
method to calculate NMOC corrected to a standard value of N2
if the EPA is concerned that excessive air intrusion will
cause a false measurement of NMOC in the LFG. The commenter
(IV-D-39) asserted that this N2 is released from the refuse
and is not a result of air intrusion.
Another commenter (IV-F-6) suggested that well
temperature and percent methane, should be used as the
infiltration indicator, instead of difficult and expensive N2
measurement techniques.
One of the commenters (IV-D-27) approved of the 1 percent
N2 limit in Method 2E while performing gas generation rate
testing, but said that 12 percent is more appropriate for
kLk-85\04 2-91
-------
operating gas collection systems. The commenter noted that it
is only above 12 percent that methanogenic bacteria become
dormant. Another commenter (IV-D-39) asserted that a small
amount of air intrusion (less than 3 percent) does not
significantly reduce methane quality, nor does it cause
subsurface fires.
One commenter (IV-D-29) suggested that the regulation
allow landfill operators a choice between portable 02 monitors
or Method 3C in order to detect infiltration in the header
system. "The commenter reported experience using portable 02
monitors and noted that they give instantaneous readings,
whereas Method 3C often requires laboratory testing. In
addition, the commenter requested that either 02 or N2 be
allowed for use in the detection of header system leaks. The
commenter suggested that the requirement be revised to a
maximum of 3.5 percent 02 content in the header system, based
on experience with LFG containing an 02 content between 0.5
and 3.5 percent without any adverse problems.
Two commenters (IV-D-30, IV-D-39) stated that there are
simpler methods for leak detection. Another commenter
(IV-D-27) suggested that the EPA establish alternative methods
for monitoring air intrusion because N2 testing is so
expensive. The commenter reported costs of $150 per well per
month. The commenter recommended a number of options for
determining air infiltration, including: (1) deviations
around a stabilized air N2 level, (2) deviations (10° C)
around a stabilized temperature at the wellhead, and
(3) surface-integrated measurement.
Response; In Method 2E as well as daily operation, the
N2 concentration in the extracted LFG is important because it
indicates whether the maximum vacuum achievable without air
infiltration is being obtained from the landfill. The N2
limit is provided as a safety measure to avoid fires and
explosions that may result from pulling too much air into the
landfill, and to avoid altering the anaerobic state of the
landfill. For compliance purposes, the main concern is that
klk-85\04 2-92
-------
the system is pulling at maximum capacity up to the point of
infiltration. The 1 percent value was based on previous
comments received from industry, which were misunderstood in
establishing 1 percent as a limit, when in reality, the
sources were using the 1 percent as a target. The reason N£
concentration was being restricted at proposal instead of (>2
•»
is that the portable ©2 meters were unable to measure ©2 to
the low levels necessary, and that 02 may be consumed and not
detected.
The monitoring provisions of the final NSPS have been
revised after consideration of the comments. The N2 limit
during operation of the collection system at the wellhead has
been increased to a level less than or equal to 20 percent as
determined by Method 3C. Because the N2 concentration limit
was raised, it is now also feasible for sources to monitor 02
to indicate the maximum vacuum achievable without air
infiltration. Therefore, a provision allowing for an 02 limit
of 5 percent as indicated by an oxygen meter calibrated
according to Method 3A of Appendix A of 40 CFR 60 has been
added to the final rules. In addition, a provision has been
added to require the operation of the collection system with a
landfill gas temperature of less than 55 °C (or the maximum
established value) demonstrated under § 60.753(c). The final
provisions require monthly monitoring of these parameters.
The N2 limit in Method 2E has also been increased to
20 percent. If a sample is found to contain more than
20 percent N2 in Method 25C, then that sample should be
removed from the collection. The equation for calculating the
concentration of NMOC in Method 25C has also been revised to
correct the NMOC concentration in the LFG sample to zero
percent N2•
As mentioned above, a provision has been added to the
final rule requiring the temperature to be maintained at less
than 55° (or higher site-specific established value) at each
well. If the LFG temperature at the wellhead increases above
the temperature threshold, the new provisions require an
kli-85\04 2-93
-------
adjustment of the vacuum to reduce the temperature. The value
of 55° C was cited by industry experts as an alert temperature
that may indicate a problem. Since temperature variability
exists between landfills and between wells within a landfill,
the provisions to establish higher operating temperatures at
individual wells has been added. A higher temperature limit
will be allowed if the owner or operator can demonstrate with
supporting data that the higher temperatures do not cause
fires or adversely affect the anaerobic decomposition of the
waste.
Comment: One commenter (IV-D-26) contended that
maintaining an 02 level in a flowing LFG stream below
1 percent is unreasonable, unnecessary and also not cost
effective. The commenter asserted that more sensitive and
accurate well adjustments are made from temperature, percent
methane, amount of vacuum, and flow volume. The commenter
stated that intruded 02 would be stripped off by the landfill,
and that temperature and percent methane would be immediately
affected by both intruded air and direct leaks into the
system.
The commenter further recommended that no 02 limitations
for individual wells be set, and that an O2 level of 8 percent
in the main header would be appropriate.
Response; The EPA is assuming that this commenter was
referring to N2 instead of ©2 (see above response) or that the
commenter was commenting from a previous version that
discussed air intrusion testing, which differs from the
proposed regulation. The commenter did not provide details
concerning how temperature, percent methane, amount of vacuum,
and flow volume could be used to determine appropriate
adjustments. The proposed regulations required monitoring of
N2 to control air intrusion. Changes to the final regulation
addressing air intrusion were discussed in the response to the
previous comment.
klk-85\04 2-94
-------
2.10 MODELING
C7TM?ntl; Two commenters (IV-D-30, IV-D-39) stated that
the use of the first-order gas rate generation model in
Method 2E was not backed up by evidence which shows it to be
more accurate than other available models. The commenters
asserted that this discourages the development of more
accurate models, and cited the modeling discussed" in the
December 1989 ASCE Environmental Engineering Journal as
examples of models under development.
Three commenters (IV-D-46, IV-D-49, IV-F-4) argued that
the EPA LFG emission models overestimate the effects and
amount of LFG produced, resulting in the installation of
control systems that are larger than necessary. The
commenters suggested using methods and technology currently in
practice at landfills.
One commenter (IV-D-55) argued that the EPA has no data
to support the use of their model equation. The commenter
asserted that the model equation is based on the premise that
the LFG generation rate is solely a function of age and the
amount of refuse. The commenter stated that LFG generation
rates are highly dependent upon fluctuating moisture content
of the refuse, and, therefore, there is no such thing as a
"gas generation rate constant" that only needs to be
calculated once. The commenter further argued that the NMOC
emissions mechanism is not described by the Scholl Canyon
model, and encouraged the elimination of the use of
mathematical formulas for applicability of controls.
Another commenter (IV-D-45) stated that because of the
health effects of NMOC, testing should be performed to
determine NMOC emission rates rather than relying on estimates
of NMOC emissions.
Another commenter (IV-D-17) stated that the final results
of the model, although based on sophisticated formulae, may be
inaccurate because of the quality of background data.
Response; Although the EPA acknowledges that other
models may be in use or under development, the Scholl Canyon
klk-85\04 2-95
-------
based model used within these regulations was chosen because
it is both simplistic and adequate for purposes of estimating
LFG emissions. The model was submitted to industry for review
at frequent intervals throughout its development (see
Docket A-88-09 subcategory II-C for Agency submittals and
subcategory II-O for industry and vendor responses). The EPA
considers it adequate and effective for purposes of these
standards. Actual landfill gas emissions data were collected
and compared to emissions estimates using the model. The
actual emissions and the modeled estimates correlated
satisfactorily (see Docket A-88-09, Item No. IV-A-l).
In the interim between proposal and promulgation of the
regulation the EPA obtained site-specific gas generation data
characterizing landfill emissions from both arid and moist
regions of the United States. The data were applied to the
input data bases proportionally, to account for the effect of
moisture on gas generation. This data and the methodology
used to assign it to the input data bases is described in the
memorandum "Methodology Used to Revise the Model Inputs in the
Municipal Solid Waste Landfills Input Data Bases" (Docket No
A-88-09, Item No. IV-M-4).
While the model is used to select the regulatory cutoff,
the NSPS allows site-specific data to be used to improve the
resulting NMOC emission rate upon which the applicability of
controls depends. As commenter IV-D-55 noted, the Scholl
Canyon model does not describe NMOC emission mechanisms;
rather it describes methane generation. In the tier system,
if the Tier 1 NMOC emissions estimates are above the
regulatory cutoff, the owner or operator may elect to sample
for a site-specific NMOC concentration to improve the NMOC
emission rate estimation. If the resulting NMOC emission rate
is still above the regulatory cutoff, the owner or operator
may also perform gas flow testing to obtain a site-specific k,
for use in the emission rate calculation.
These options improve the applicability of the model to
the individual landfill. The gas flow testing, if performed,
klk-85\04 2-96
-------
can also be used to determine a site-specific area of
influence for use in determining system design. (See
section 2.12, "Design Specifications," for discussion of
system design.)
The EPA understands that the tier default values have
been misused (e.g., emission inventories, control system
•»
design, etc.). The default values should only be used for
applicability of the regulations. They were selected to be
used as a screening tool to determine applicability of the
*
control requirements of the regulations. They should not be
used to estimate emissions for inventories or control
equipment design.
Comment: One commenter (IV-D-32) discussed various
aspects of the equations used in calculating the NMOC emission
rate using default information in S 60.753 of the proposed
regulation. The commenter stated that the proposal BID and
regulation did not clearly describe how the values M and R
were derived, and recommended either the BID be made
consistent with the regulation or the definition for R and M
exclude discussion of nondegradable waste. In addition, the
commenter requested that the variable C^QC/ which is defined
differently in two equations, be used in a clear and
consistent manner. The commenter noted that the equation in
§ 60.753(a)(1)(ii) of the proposed regulation differs from the
equation on page 9-6 of the proposal BID in that the time
since closure (c) does not always equal zero and e~ck does not
always equal one.
The commenter reported that the regulation does not
clearly state what value should be used for the NMOC
concentration, and that S 60.753(a)(2) refers to the
calculated emission rate of NMOC, not to the NMOC
concentration. The commenter also suggested that it is
unclear whether the annual emissions rate is determined using
the 8,000 ppmv default value for NMOC concentration or using
the site-specific value calculated via S 60.753(a)(3) along
with the site-specific k value. Lastly, the commenter
klk-85\04 2-97
-------
requested clarification of how frequently the NMOC
concentration should be revised.
Response: The definition of CNMOC is the same in all
equations. "As hexane" was inadvertently left off one of the
definitions, and has been corrected in the final regulation.
The equation in § 60.753(a)(1)(ii) of the proposed NSPS is for
new landfills opening after May 31, 1991. It was assumed that
new landfills will not be closed by promulgation of this
regulation, in which case e"*0 is equal to one. However, this
section is referred to by the EG in S 60.34c, which may
require calculation of an NMOC emission rate after landfill
closure. Therefore, the equations in S 60.754(a)(1) of the
renumbered final NSPS have been changed to include the closure
term e~*c. The use of default or site-specific values, when
calculating the NMOC emission rate, depends on what tier the
owner or operator is in at the time. The Tier system should
be viewed as a step system with Tier 1 being the first step.
A diagram of the entire tier system was provided in figure 1,
Overall Three-Tiered Approach for Determination of Control
Requirements, in the proposal preamble. Section 60.754(a)(1)
of the final renumbered NSPS specifies that 4,000 ppmv as
hexane be used for calculating the mass emission rate of NMOC
(MNMOC)• Paragraph (a)(2) correctly refers to the calculated
MNMOC when comparing it to the 50 Mg/yr standard. This
process is referred to as Tier 1, where default values are
used to calculate MNMOC and then compared to 50 Mg/yr. Tier 2
incorporates a site specific NMOC concentration and is
described in S 60.754(a)(3). Tier 2 would only be used if the
MNMQC as calculated in Tier 1 is greater than 50 Mg/yr. If
the MNMOC calculated in Tier 2 is greater than 50 Mg/yr, the
owner or operator can elect to install controls or use Tier 3,
which is described in S 60.754(a)(4). Section 60.754(a)(4)
has been revised to specify that both the site-specific NMOC
concentration and site-specific methane generation constant
(k) be used in Tier 3.
kLk-85\04 2~98
-------
Tier 2 requires that a site-specific NMOC concentration
be determined from a number of surface locations at a
landfill. Many commenters stated that the statistical
approach to calculate the number of samples and sampling
frequency is not supportable. In an effort to address the
comments, the required number and location of the sampling
• %
probes were revised. A landfill performing Tier 2 is required
to take two samples per hectare of surface area, up to
50 samples. Because the confidence level calculation was
*
removed, the site-specific NMOC concentration is required to
be recalculated every five years. The ten year recalculation
period option has also been removed.
Because of the lower NMOC emission rate stringency level
of 50 Mg/yr and the fewer number of landfills affected by the
regulations due to the 2.5 million Mg maximum capacity
exemption level, a single tier 2 recalculation period of every
5 years is considered justified and not overly burdensome.
The lower stringency level makes it more likely that a
landfill's NMOC emission rate could increase such that it
significantly exceeds the 50 Mg/yr stringency level during a
10 year period.
Additional guidance has been incorporated into the final
regulation in § 60.754(a) for determining values for M^ (mass
of refuse in the itn section, Mg) and R (average annual refuse
acceptance rate, Mg/yr). As specified in chapter 9 of the
proposal BID, the mass of the nondegradable refuse should be
subtracted from the total mass of refuse in a particular
section of the landfill or from the refuse acceptance rate to
avoid overestimating the LFG emission rate.
Comment; One conunenter (IV-D-25) suggested using
site-specific kinetic coefficients in Tier 3, instead of site
specific emission rates. The commenter gave information on
how the kinetic coefficients would be estimated.
Response: The purpose of Tier 3 is to determine a site-
specific methane generation rate constant (k). The k value is
determined from a site-specific emission determined by
kli-85\04 2-99
-------
extracting LFG from a portion of the landfill (i.e.,
installing gas extraction wells) .
one industry commenter (IV-D-27 and IV-F-5)
noted that a conversion factor used in the calculation of the
default concentration of NMOC fails to account for the final
product needing to be given "as hexane." The conunenters
concluded that this resulted in a default value nearly five
times greater than the values upon which it was based, and
requested that the default value be recalculated. The
•
conunenters also contended that the mass emission rate of NMOC
would be affected by the "as hexane" error. The commenter
found the different conversion factors provided in the
proposed regulation and BID to be overly confusing, and
recommended an alternative conversion factor, providing the
calculations upon which it was based.
Response: The problem with the conversion factor noted
by the commenter is actually a problem within the section of
the regulation where the NMOC concentration from Method 25C is
used to calculate the NMOC emission rate. This error occurred
as an oversight in the typing of the proposed regulation,
which should have included additional text in the proposed
NSPS.
The appropriate text has been added to S 60. 754 (a) (3) to
^indicate that the NMOC concentration from Method 25C must be
divided by 6 to convert from NMOC concentration as carbon to a
concentration in terms of hexane. The conversion of NMOC
concentration from as carbon to as hexane was performed
correctly in the analysis upon which the selection of the
regulatory emission rate cutoff was based.
2.11 TEST METHODS
Comment t One commenter (IV-D-10) expressed concern that
the proposed test Methods 25C, 3C and 2E contain procedures
that can be both laborious and costly. The commenter
suggested that the regulations include provisions that do not
limit owners or operators to only these three methods if other
equivalent methods exist or may be developed. The commenter
klk-85\04 2-100
-------
stated that this will reduce costs and allow a field sampling
technique they are developing to test methane and NMOC
emission rates that will be less expensive and more accurate
than current methods.
Response; Owners and operators may propose alternative
methods, provided they are approved by the appropriate
reviewing agency.
CoftHnept; One commenter (IV-D-54) suggested that the
nomenclature be changed from NMOC to TGNMO in proposed test
Method 25C because the technique for analyzing NMOC is
substantially similar to the technique for TGNMO. The
commenter stated that it would be less confusing for the
nomenclature to remain TGNMO for the technique.
Response; The EPA has defined CNJJOC and NMOC within the
methods according to the purposes for which the methods were
developed. Since the surrogate for the designated pollutant
in these regulations is NMOC, Method 25C, which was developed
to support these regulations, references NMOC.
2.11.1 Nonmethane Organic Compound Sampling and Analysis
Comment; One commenter (IV-D-19) requested that
alternatives other than Method 25C (for example, meters, SUMMA
canisters as in the EPA method TO-14, and total hydrocarbons,
and total nonmethane hydrocarbon analyzers) be allowed in the
regulations for the sampling and measurement of LFG. Another
commenter (IV-D-3) suggested that EPA Method 18 and
Method 8240 be used in place of Method 25, because Method 25
is more expensive. The commenter also stated that Method 25
does not allow for chemical-specific data, would not indicate
any contaminants at significant toxic levels, and does not
meet the criteria set forth in RCRA guidelines SW-846. The
commenter further indicated that the sampling depth in
Method 25 is too shallow and, therefore, yields no
representative NMOC concentrations.
One commenter (IV-D-32) recommended that test Method 25C,
used for collecting and analyzing NMOC concentrations from
probes and referenced to in § 60.753(a)(3), be incorporated
klk-85\04 2-101
-------
into the regulation by reference. The commenter was, however,
concerned about the use of a sampling requirement that may
create up to 50 holes through the cover of the landfill every
5 to 10 years. The commenter suggested that language be
included in the regulation or test method to decommission the
sampling wells to maintain the integrity of final^cover.
Also, another commenter (IV-D-55) stated that penetrations of
the landfill cover to install additional wells or for sampling
provide avenues of escape for the toxic compounds. The
commenter recommended that the approval of mitigation measures
be required pri r to cover penetration.
One commenter (IV-D-39) asserted that the use of
Method 25C for determining NMOC concentrations is questionable
because: (1) probe samples and gas extraction well samples do
not typically agree with each other, (2) probes only give a
static measurement of NMOC under the cap, and (3) probe
samples are not representative of the heterogeneous nature of
landfill wastes. The commenter recommended that a number of
methods should be allowed, including Method 25C, as well the
collection of bag samples from a larger area of the landfill
at the surface, and sampling wells sunk completely through the
trash that could later be used in the collection process.
One commenter (IV-D-26) stated that operators of multiple
landfill sites should be allowed to statistically determine
average NMOC concentrations throughout the landfill system,
rather than on a landfill-by-landfill basis. The commenter
argued that for a gas analysis to be truly representative of
what is in the landfill, gas needed to be collected within the
trash and not beneath the cap.
Another commenter (IV-D-55) asserted that due to the
uneven distribution of pools of leachate (the source of most
NMOC emissions), the use of concentration samples from only
five probes can lead to extremely misleading conclusions.
One industry commenter (IV-D-27) supported the
requirements for determining NMOC concentration with an
80-percent confidence, but requested that composite sampling
klk-85\04 2-102
-------
be allowed on the additional sampling (maximum 50), arguing
that the average concentration is all that is finally used.
The commenter noted that this would greatly reduce the cost of
such sampling and analysis. This commenter also suggested
that an alternative be allowed to installing probes.
One commenter (IV-F-6) claimed that the 80 percent
confidence interval in Method 25C is being compared to the
variation between the samples. The commenter asserted that
since the. focus is on the difference between the 5 sample
averages and the 8,000 ppmv, there is no reason to take more
samples when the difference between them is large.
Two commenters (IV-D-30, IV-F-3) stated that the
80 percent confidence level for NMOC sampling is not based on
sound logic since there is no proof that the distribution of
LFG is normally distributed as is the t-statistic on which the
confidence level is based.
One commenter (IV-D-39) asserted that no data are
presented to show that the student t-test is a valid procedure
for analyzing data collected from LFG sampling. The commenter
argued that other environmental monitoring programs such as
groundwater monitoring data have shown that the student t-test
is not a valid test in most cases and that the EPA has
previously allowed more appropriate alternative statistical
analyses. The commenter suggested that a specific statistical
test not be required, but rather that an appropriate
statistical method be used.
Response; When specifying a method for demonstrating
compliance, the EPA seeks to select a method that is as simple
as possible but provides information adequate for establishing
compliance. Method 25C was developed for this rule because it
measures total nonmethane organics, which is the surrogate
specified within these regulations for the designated
pollutant. Methods that do not separate methane from the
other organic compounds, such as Method 21, are not readily
amenable for measuring NMOC in LFG. Methods TO-14 and 8240
are not appropriate alternatives to Method 25C, for the
kLk-85\04 2-103
-------
following reasons. Method TO-14 is more expensive than
Method 25C and analyzes specific compounds rather than simply
NMOC. Method 8240 is a GC/MS analytical procedure for a
predetermined list of compounds and could not be used
effectively for measuring NMOC concentration.
Based on the comments received, the EPA decided to
specifically allow the use of Method 18 or Method 25 for
determination of reduction efficiency. If Method 18 is used
it must be speciated at a minimum for the compounds listed in
the most recent version of AP-42. While the EPA believes
Method 18 may be more costly to implement than Method 25, it
does not doubt the adequacy of either method for determining
reduction efficiency. However, other test methods may be used
for any of the specified methods if they are approved by the
appropriate reviewing agency. Although other methods may be
used, if properly validated, usually only one or two
established EPA methods are specified because they have been
demonstrated to provide valid results and because the
comparative results from several sources reporting to one
agency are more meaningful when the same analytical method has
been used.
A requirement has been added to the regulation to refill
the probe holes with cover material once sampling has taken
place. The owner or operator may choose to leave the probe in
place and simply plug the sampling probe or remove the probe
and refill the hole with cover material.
The NMOC sampling requirements of tier 2 in the final
regulation have been revised. Many commenters stated that the
statistical approach to calculate the number of samples and
sampling frequency is not supportable. In an effort to
address many of the comments, the required number and location
of the samples were revised. A landfill performing the tier 2
sampling to obtain a site-specific NMOC concentration is
required to take two samples per hectare of surface area up to
50 samples. A landfill owner or operator may take more than
klk-85\04 2-104
-------
50 samples, but all the samples must be included in the
calculation to obtain the average NMOC concentration.
Due to the large variation in NMOC concentration from
landfill to landfill, using average NMOC concentrations from
multiple landfill systems would not provide a reasonable basis
for installing collection and control systems at individual
• *
landfills. The EPA considers that when the regulatory cutoff
is exceeded and NMOC sampling is performed, the site-specific
NMOC concentration should be the basis for applicability, not
•
an average concentration based on multiple landfills.
Additionally, a multiple landfill average might result in
control applied to fewer landfills. Instead of landfills
emitting greater than 50 Mg NMOC/yr being controlled while
others emitting less than 50 Mg NMOC/yr are not, the use of a
multiple-landfill average NMOC concentration might exempt all
of the landfills in the system. The NMOC sampling is meant to
improve the accuracy of the estimate for landfills near the
regulatory cutoff, to determine if the specific landfill
warrants control.
The sample probe depth requirement has been changed to
read sunk "at least" 3 feet below the cover material or cap to
give some flexibility in sampling.
Composite sampling can be allowed only if each individual
sample is of equal volume. This is to insure that the
resulting NMOC concentration is equal to the value that would
be obtained if an average value from concentrations of
multiple samples were used.
2.11.2 Method 2E
Comment; Many commenters (IV-D-25, IV-D-30, IV-D-31,
IV-D-34, IV-D-39, IV-D-47, IV-F-4) questioned the accuracy and
validity of Method 2E. One commenter (IV-D-30) argued that
Method 2E is based on questionable engineering assumptions,
and limited testing of a volume of the landfill that is
unknown at a single point in time, since the true region
influenced by the extraction well is unknown. The commenter
maintained that the EPA did not provide documentation to
kli-85\04 2-105
-------
confirm the accuracy of the proposed test method. Two
commenters (IV-D-25, IV-D-34) stated that Method 2E either
overestimates or underestimates well-spacing requirements,
depending on landfill characteristics. While another
commenter (IV-D-46) stated that the treatment systems will be
overdesigned and inappropriate for small and medium size
• *
landfills. One commenter (IV-F-4) stated that Method 2E may
overestimate well spacing by two to three times.
Another commenter (IV-D-31) stated that active extraction
*
testing using Method 2E lacks accuracy, is too involved, and
is too costly to be the basis for design or the decision to
install collection systems. The commenter claimed that the
extraction well depth should not extend to 75 percent of the
landfill depth, except in small landfills, due to the expense
of wells deeper than 30.5 to 36.5 meters. The commenter
recommended that perimeter wells could catch gas escaping from
deep wells.
Several commenters (IV-D-25, IV-D-27, IV-D-30, IV-D-31,
IV-D-34) were concerned about the cost of Method 2E. Two
commenters (IV-D-25, IV-D-31) noted that in the case of small
landfills, the cost of performing Method 2E could exceed the
cost of an adequate control system. Two commenters (IV-D-25,
IV-D-34) argued that using Method 2E to determine well spacing
would increase costs because wells would be spaced too close
together, due to fluctuations in barometric pressure.
Response: The EPA developed Method 2E with input from
industry representatives. Industry provided experience on
techniques that the EPA then developed into Method 2E. Since
•
these techniques are used by industry representatives, the EPA
is confident that Method 2E can be used effectively to
estimate the area of influence. The final regulations,
however, no longer require a specific determination of the
area of influence, so sources that are not comfortable with
Method 2E are not required to use it.
Method 2E was also developed to be used to determine a
site-specific methane generation rate constant (k), for use in
klk-85\04 2-106
-------
Tier 3 of the applicability determination. Method 2E, as a
method of determination of k, is based on the Scholl Canyon
model and the area affected by a given well (ROI), as
determined by testing. Since the site-specific k value would
replace the default k value, the EPA is confident that a
site-specific k value determined by Method 2E would better
represent an individual landfill than the default k value. It
should be noted here that use of the Tier system is also
optional, and sources not comfortable with the use of
Method 2E could document the sufficiency of another method, or
install controls.
Since the EPA removed the prescriptive requirements for
collection system from the final regulations, and replaced
them with design criteria, the concerns expressed by
commenters over these issues should be alleviated.
The cost of performing Method 2E was taken into account
when the tier default values were selected. Default values
were selected in an attempt to minimize the number of
landfills that would perform Tier 3 and then not be required
to install controls. In other words, the default values were
selected in an effort such that landfills that were estimated
to emit more than 50 Mg/yr by Tiers 1 and 2 and therefore
elected to perform Tier 3 would still likely need to install
controls, thereby making use of the wells already installed
for Tier 3. This is also a factor landfill owners and
operators will need to take into account when deciding whether
to advance to Tier 3 or to install controls after Tier 1 or
Tier 2. The EPA acknowledges that landfill owners and
operators will base how far to advance in the tier system on
site-specific factors, including cost.
The EPA also increased the maximum capacity exception
level to 2.5 million Mg. This exemption will exempt
approximately 90 percent of all landfills from the
requirements of the regulations.
Comment; Several commenters (IV-D-25, IV-D-30, IV-D-31,
IV-D-34, IV-D-51) were concerned about the impact of
kLk-85\04 2~107
-------
barometric fluctuations on the accuracy of Method 2E. One
commenter (IV-D-31) reported that, in his experience, pressure
differences are very slight and these differences can be
overwhelmed by barometric fluctuations. The commenter
suggested placing pressure probes closer to the well, at 3,
7.6, and 15.2 m, and plotting the pressure differentials
• *
versus the natural logarithm of distance to extrapolate to get
the distance at zero pressure difference. The commenter
contended that the correction for barometric pressure does not
take into account time lags for the landfill pressure to
equilibrate to barometric swings. The commenter maintained
that extracting two void volumes does not assure that "new
gas" is being collected or that gas is being extracted at the
same rate it is being generated. The commenter recommended
that steady state pressure distributions should be achieved
first, meaning that pressures are rising or declining at a
steady gas extraction rate.
Another commenter (IV-D-51) suggested that better methods
for determining the area of influence for a given well (other
than Method 2E) included continuous recordings of probe and
atmospheric pressure or spreading out the time frame for spot
monitoring performed at the same time each day.
Response: In Method 2E, pressure readings are taken,
and, as in the case of all pressure readings, these pressure
readings are measured as a pressure differential. In this
case, it is the difference in pressure between the atmosphere
(barometric pressure) and the landfill. In Method 2E, the
pressure differential is corrected for barometric pressure to
determine the landfill pressure. It is irrelevant that the
correction of barometric pressure does not take into account
the time lag between barometric pressure changes and landfill
pressure changes, because in Method 2E the concern is with the
relative difference in landfill pressure from probe to probe
at a given moment in time.
The barometric fluctuations may affect the landfill gas
generation rate; however, the landfill gas generation rate is
klk-85\04 2-108
-------
being determined over a period of time where varying
barometric pressures impact the gas generation rate and these
effects are being averaged together. Since the extraction
wells must function during all barometric conditions, any
conditions in which Method 2E is performed are conditions that
are more or less likely to occur and are applicable to the
landfill.
After review and consideration of comments, the EPA has
revised Method 2E to allow the use of a semi-logarithmic plot
of pressure differentials versus distance from the wellhead
for determining ROI.
Method 2E is being kept in the regulation as an
alternative means for establishing applicability, as a part of
the tier system. In Tier 3, an owner or operator has the
option to perform Method 2E to develop a site specific gas
generation rate constant for use in estimating the NMOC
emission rate. There may be other methods that would estimate
the site specific gas generation rate constant more
accurately, but these would entail more cost and more testing
time. The EPA is confident that Method 2E sufficiently
estimates the site specific gas generation rate constant.
However, this method does not have to be used. An owner or
operator can install controls after Tier 2 and not perform
Tier 3 (Method 2E), or the owner or operator can propose
another method for estimating the gas generation rate
constant.
When Method 2E is used as a means for estimating the area
of influence, the EPA does not believe that either continuous
recording or prolonged monitoring will improve the accuracy of
the area of influence estimate significantly. Method 2E
already requires that barometric pressure measurements be
taken at the same time as the probe pressure readings. Also,
Method 2E requires that the pressure measurements be taken
every 8 hours over several days or more, which would mean that
pressure measurements are taken at the same time each day.
ktt-85\OA 2-109
-------
Comment: One conunenter (IV-D-31) stated that single
wells are preferred over the cluster wells regardless of
whether the history of the site is known, because at sites
where the history is known generation rates varied by factors
of 1.5 to 3.
Response: A landfill owner or operator has the option to
choose between using three cluster wells or five wells spaced
evenly over the landfill. The regulation does not require the
use of cluster wells for Method 2E testing. In fact, cluster
«
wells should not be used if the composition of the refuse, age
of the refuse, and the landfill depth of the test area cannot
be determined. Where these factors can, however, be
determined, cluster wells are appropriate. Therefore,
landfill operators have two options for siting wells in
Method 2E testing, when the required data is available.
Comment: Three commenters (IV-D-27, IV-D-31, IV-D-39)
were concerned with the depth of perforation of the well due
to the possibility of air infiltration. One conunenter
(IV-D-27) suggested that a perforation depth should start no
closer to the surface than 6.1 m, while the second conunenter
(IV-D-31) suggested that only the bottom one-third of the well
be perforated. The second commenter (IV-D-31) pointed out
that less perforations would result in a smaller radii of
influence. The third commenter (IV-D-39) asserted that a
2/3 perforated section was appropriate for wells deeper than
13.7 m, but for shallower wells a solid section should be no
less than 4.6 m, unless a synthetic liner is being used. The
commenter asserted that the specific design standards in the
proposal be replaced with a performance standard that can be
met by qualified professional designers, who can design an
optimal gas recovery system.
Response: These commenters have raised a valid concern
regarding well perforations too close to the surface.
Accordingly, the provisions in S 60.759 have been revised to
provide only criteria for designing collection systems, rather
than prescriptive specifications.
kli-85\04 2-110
-------
Comment; One commenter (IV-D-27) opposed the use of
Method 2E to calculate maximum expected gas generation rate in
S 60.757(b)(1)(i) of the proposed regulation. The commenter
argued that using Method 2E here is in conflict with the
calculation equation provided in S 60.754 of the proposed
regulation which allows, but does not require, aerate to be
determined through Method 2E.
Response: Sections l through 4 of Method 2E do not apply
to a controlled landfill. In addition, the final regulations
have been revised at S 60.758(b)(l) to allow the owner or
operator to calculate the maximum expected gas generation flow
rate according to S 60.755(a)(1) or any other method to
determine maximum flow rate, as long as the method is approved
by the Administrator.
Comment; One commenter (IV-D-39) discussed the
requirement of using a blower with a flow rate of 8.5 m3/min.
The commenter stated that a larger or smaller blower may be
needed, depending on site conditions.
Response; The blower capacity requirement of 8.5 m3/min
is the estimated minimum capacity requirement for performing
Method 2E. As the commenter pointed out, depending on the
flow rate conditions at each particular site, a larger blower
capacity may be required. Therefore, the language in
Method 2E has been revised to indicate a blower capacity
requirement of at least 8.5 m3/min.
2.11.3 Method 3C
Comment; One commenter (IV-D-27) suggested that only one
calibration standard is necessary for calibrating the thermal
conductivity detector because of its linear scale.
Response; The requirement for three calibrations is
included in Method 3C because it was previously determined to
be appropriate during the development of Method 3. Requiring
three calibrations enhances the statistical validity of the
calibration test, and the EPA does not consider the three
tests overly burdensome.
kli-85\04 2-111
-------
2.12 DESIGN SPECIFICATIONS
Cprnm^nt ? one commentef (IV-D-46) alleged that the
proposed regulations may encourage untrained "landfill gas
engineer consultants" to offer their services to city
administrators. Two commenters (IV-D-25, IV-D-34) were
concerned that Method 2E is very complex and will be used by
• %
inexperienced gas system designers which will affect the
integrity of the results.
Response: In determining whether to hire a consultant,
•
landfill owners and operators should obtain information on the
previous experience and qualifications of the consultant and
on their professional memberships and certifications. The
landfill industry, professional organizations, and State air
pollution control agencies may be able to provide city
administrators with information about reputable landfill gas
engineering consultants. In response to commenters' concerns,
the final regulations indicate that the gas collection system
design plans must be prepared by a professional engineer.
Also, it should be noted that use of Method 2E is optional and
might not be used at many landfills, so there should not be a
shortage of experienced contractors.
Comment; Two commenters (IV-D-30, IV-D-36) contended
that the collection and control design criteria used by the
EPA is based on scientifically unproven and, therefore,
invalid models and tests. One commenter (IV-D-30) mentioned
that various California regulatory agencies had based their
standards on actual emission measurements and not on models.
Two commenters (IV-D-46, IV-D-49) said that the recommended
gas treatment systems are overdesigned for smaller landfills
and that the models used overestimate the amount of LFG
produced.
Response; The gas generation model and the technical
basis for gas collection system design were reviewed by
industry frequently during their development and all comments
submitted by industry were considered (see Docket No. A-88-09,
Items II-c-ll, II-C-22 and ll-c-24; and Item Nos. II-D-38 to
kli-85\04 2-112
-------
II-D-43, II-D-47 to II-D-50 and II-D-52 to II-D-54). The EPA
considers the model reasonable for these regulations and is
currently using the model in a number of other studies as
well.
As stated in an earlier response, the Tier default values
should only be used for determining applicability of the
regulations. They were selected to be used as a screening
tool to determine applicability of the control requirements of
the regulations and should not be used to estimate emissions
for inventories or control equipment design.
Comment: One industry commenter (IV-D-27) argued that
the equation for determining gas mover sizing incorrectly
sizes for the peak flow rate over the life of the landfill and
not the maximum LFG flow rate expected over the life of the
gas moving equipment. This commenter pointed out that gas
movers can be upgraded or downgraded as the LFG moving needs
change.
Two commenters (IV-D-39, IV-F-6) questioned the
relationship between maximum expected flow rate and gas
collection equipment life. The commenters stated that
equipment life should not have an effect on gas flow rates and
should not be factored into the value of t.
One commenter (IV-D-39) requested clarification on
whether a gas collection system needs to be designed to handle
the maximum expected gas flow rate from the onset or if the
system can be designed in phases as the landfill is developed.
The commenter recommended that phased design and installation
be allowed.
Response; The EPA agrees that upgrading and downgrading
equipment should be allowed, and the definition of the
parameter t has been changed to reflect the time frame the
owner or operator intends to use the equipment, instead of the
equipment life. The new definition states that t is equal to
the active life of the landfill or the age of the landfill
plus the time the owner or operator intends to use the
equipment, whichever is less. Equipment can now be sized for
klk-85\04 2-113
-------
the maximum LFG flow rate expected over the use of the
equipment and not over the life of the equipment.
The equation containing the parameter t in $ 60.755
calculates the maximum LFG flow rate for the period of time
the equipment is being used. The parameter t is defined as
the oldest active age of the landfill while a given piece of
equipment is being used. For a landfill that will close
before the completion of the intended equipment use period, t
is the total active life of the landfill. For a collection
*
system that the intended equipment use period will be up
before landfill closure, t is the age of the landfill when the
equipment will be taken out of service or the age of the
landfill plus the intended time of equipment use. For
equipment that will be used after closure only, t is the age
of the landfill when the equipment is installed.
2.12.1 Collection System Design
Comment; Many commenters (IV-D-7, IV-D-9, IV-D-27 and
IV-F-5, IV-D-36, IV-D-38, IV-D-49, IV-D-52, IV-D-56, IV-F-4)
wanted more flexibility to be incorporated into the design
standards. The commenters asserted that these designs should
be more site-specific and determined by the designers and
owners. Many of these commenters requested that the
regulation allow landfills operated and designed based on the
SCAQMD regulation to be considered equivalent to a landfill
designed and operated under these regulations. One industry
commenter (IV-D-27) urged the EPA to provide less restrictive
specifications for well construction and system components,
adding that many effective systems have been used that would
not meet these specifications.
Another commenter (IV-D-37) conceded that the regulation
includes a mechanism for flexibility through alternative
design plan submittal to the Administrator or the designated
reviewing agency, but requested that the EPA further encourage
States to allow such flexibility. Two commenters (IV-D-52,
IV-F-4) stated that the proposed regulation does not take into
klk-85\04 2-114
-------
consideration alternative methods of LFG control in use at
existing MSW landfills.
Two conunenters (IV-D-25, IV-D-34) noted that although the
proposed NSPS allows for the submittal of an alternative
design, the NSPS and EG require that the collection and
control system be designed in conformance with chapter 9 of
the BIO, where the design specifications are far too rigid.
Because of this rigidity, the commenter stated that systems
meeting the SCAQMD standard would not meet the alternative
«
design criteria in the proposed standard.
Another industry commenter (IV-D-27) argued that the
collection system design specifications in the NSPS should be
moved to the proposal BID and used solely as guidance, rather
than as a design specification. The commenter noted that
industry experts would submit site-specific designs to the
State agencies for approval, and that this would foster
creativity and the development of innovative systems.
Response; After consideration of the comments, the EPA
agrees that the specific design criteria in the proposed rule
may be overly restrictive and not the most appropriate design
for all landfills. The design specifications in the proposed
rule may be useful in designing active vertical collection
systems. However, because of the many site-specific factors
involved with landfill gas collection system design,
alternative systems may be necessary. Therefore, the
prescriptive specifications have been removed and S 60.759 has
been revised to present more general design criteria for
active collection systems. This will allow flexibility and
allow, or even encourage, alternative designs. The final
standards require all owners or operators to submit design
plans to the State agency for review. The design plans must
demonstrate that the criteria in S 60.759 are met or that the
design is a sufficient alternative, and must be signed by a
registered professional engineer. These provisions allow for
use of a wide variety of system designs. Designs could
include vertical wells, combination horizontal and vertical
klk-85\04 2-115
-------
collection systems, or horizontal trenches only, leachate
collection components, and passive systems. Any design can be
used as long as an adequate design plan is submitted and
approved.
Additionally, landfill owners or operators can use
section lll(h)(3) of the CAA to request approval of gas
• %
collection systems that provide equivalent control, but do not
comply with either the specifications in the regulation, or
with the plan development and review requirements.
*
The final EG for collection systems references the
NSPS. For EG based on sources of health-related pollutants,
States are required to submit plans for EPA approval that
provide emission limitations at least as stringent as the
NSPS. An owner or operator of a system designed for the
SCAQMD standard would need to demonstrate that it effectively
addresses the design criteria in §S 60.752(b)(2) and 60.759.
The final EG has been revised as follows to clarify that
State plans must require installation of collection and
control systems that are equivalent to those required in the
NSPS:
11... meeting the conditions provided in
S 60.752(b)(2)(ii) of this part."
Comment; Two commenters (IV-D-25, IV-D-34) recommended
that the regulations incorporate an alternative collection
system design provision, which would establish a performance
standard based on the SCAQMD rule. The SCAQMD rule uses
integrated surface sampling of TOC to determine the need for
additional gas control. This would allow more flexibility for
the gas collection designs. One commenter (IV-D-37) noted
that their State regulation requires that gas collection
systems be designed so that surface concentrations of TOC
measured as methane do not occur at levels above 1,000 ppmv or
along the gas transfer path. The commenter asserted that the
surface test encourages system maintenance. A fourth
commenter (IV-D-55) also recommended that a surface emission
standard be established which landfill operators must
kli-85\04 2-116
-------
maintain, thereby allowing maximum design flexibility and
encouraging more cost effective innovations.
Another commenter (IV-F-6) maintained that production
tests should not be required for gas collection system design
because they are inaccurate, and that they should be replaced
with the use of operating criteria. The commenter advised
that all mandatory design features should be removed from the
provisions and that all designs should be produced by
certified professional engineers instead.
*
Response: The final NSPS allows for collection system
design based on either the criteria provided in § 60.759 of
the NSPS or an alternative design, provided that the
alternative meets the requirements in § 60.752(b)(2)(ii) and
is submitted for review. The final NSPS differs from the
proposed regulation in that it no longer provides prescriptive
design specifications.
One commenter was concerned about the integrity of the
landfill cover and that cracks in the cover could allow
emissions to the atmosphere even when an effective collection
system has been installed. As mentioned in the proposal
preamble and by commenter IV-D-26, surface emission monitoring
as used in the SCAQMD seems appropriate for determining that
closer well spacing is in fact needed. As mentioned in the
proposal preamble, the EPA was already considering what role
the California test might reasonably fill in these regulations
(see 56 FR 24492-24493).
The EPA considers surface emission monitoring to be an
appropriate tool for monitoring both cover integrity and the
effectiveness of well spacing. Therefore, some aspects of the
surface emission monitoring test have been incorporated in the
new § 60.753, where all of the operational provisions for the
collection system have been brought together.
After initial installation of the collection system,
owners and operators will be required to operate the
collection system with a methane concentration less than
500 ppm at all points around the perimeter of the collection
klk-fl5KM 2-117
-------
area and across the surface of the collection area following a
serpentine pattern spaced 30 meters apart.
Compliance with this operational standard is to be
demonstrated by monitoring surface concentrations on a
quarterly basis using an organic vapor analyzer, flame
ionization detector, or other portable hydrocarbon monitor.
• %
For closed landfills, if three successive quarterly monitoring
periods fail to indicate any methane concentrations of 500 ppm
or greater, then the owner or operator may skip to an annual
*
monitoring frequency.
If an instrument reading of 500 ppm or greater is
produced, the location of the exceedance must be recorded, and
cover maintenance or adjustment to the vacuum at adjacent
wellheads must be made within 10 days. The 10-day schedule
was selected to allow the personnel to continue monitoring
without stopping to make adjustments, but to assure that
conditions at the locale of the exceedance are attended to
quickly.
The location of the exceedance must be remonitored within
10 days. If a second exceedance is recorded at the same
location, additional adjustments shall be attempted and
remonitoring performed within 10 days. Any location that
exceeds the 500 ppm reading 3 times within a quarterly period
must install a well or other collection device within 120 days
of the first exceedance.
The methane concentration level of 500 ppm was chosen
based on data received from numerous sources, including:
(1) information provided by the SCAQMD stating that this was
an appropriate level and the level used at landfills in that
district; (2) information indicating that some leak detection
programs for other industries currently use 500 ppm and
analyzers are capable of detecting this level;
(3) instrumentation specifications citing this as an
appropriate number and that familiarity with this level is
broad; and (4) site visits conducted by the EPA indicating
that 500 ppm is an acceptable detection level.
klk-85\04 2-118
-------
Comment; One commenter (IV-D-20) stated that S 60.758(b)
in the proposed regulation should be stated more clearly,
suggesting it follow the description given in the summary.
Another commenter (IV-D-29) stated that the preamble
explains that the pressure at the wellhead should be negative
pressure to collect the gas adequately, but that the
regulation does not give this detail. The commenter suggested
that this be added to the regulation.
Response; The final NSPS does not present design
specifications for a specific gas collection system, but
includes design criteria that the EPA believes provides a
level of detail and clarity necessary to allow owners and
operators to design collection wells meeting BDT.
The final NSPS requires that pressure in the gas
collection header be monitored on a monthly basis in
S 60.756(a). Section 60.755(a)(3) requires that negative
pressure be maintained, or an additional well be added to the
system, except in certain specified situations.
Comment; One commenter (IV-F-6) noted that the system
designs and diagrams in the preamble failed to provide for
either expansion joints or pipe sloping for drainage.
Three commenters (IV-D-20, IV-D-22, IV-D-55) contended
that settlement of the refuse mass after extraction well and
header line installation is not taken into consideration in
§ 60.758(b)(2) of the proposed regulation. One commenter
(IV-D-55) recommended that the regulation require that swing
joints, slip lines, or other acceptable devices that will
allow the collection system to move with the landfill without
the collection system breaking be installed. One commenter
(IV-D-20) suggested that the majority of header piping be
buried underground in severe winter areas, and suggested that
provisions be added for routine investigations of buried
lateral lines that may become fractured. Another commenter
(IV-D-22) questioned the effects of settlement of extraction
wells which are 30 m on-center through impermeable caps.
kli-85\0* 2-119
-------
One commenter (IV-D-20) warned that gas extraction wells
should usually be located as close to the base of the landfill
as can be achieved to prevent problems associated with low
vertical refuse permeability. The commenter further
recommended that, in the case of landfills with leachate
collection systems, the extraction well should terminate at
approximately 3 m above the leachate collection system.
Response; The EPA agrees with the commenters concerns
regarding settlement. The figures and diagrams provided in
the preamble to the proposed regulations were intended to
illustrate basic system components, and were not intended to
be exhaustive. Because the final regulations require all
design plans to be submitted to the Administrator for
approval, but do not provide specific designs for gas
collection systems, the use of slip lines, swing joints or
other devices, and the location and specific length of header
pipes, is neither required nor precluded by the final NSPS and
EG. The use of these devices can be determined during the
site-specific design.
The EPA considers this level of flexibility appropriate
for the regulation and believes that operators or owners will
choose the appropriate placement for their site specific
situation and include that in their design plans. Also, if a
State or a landfill owner/operator has a particular concern
about pipe freezing or the well depth, they can address that
in their specific design plan.
Comment; One commenter (IV-D-32) suggested that
provisions be added to the regulation requiring that the LFG
collection system design be capable of controlling the
off-site migration of subsurface LFG.
Response; The EPA considers collection and control
systems designed to meet the criteria in § 60.759 of the final
NSPS to be sufficient for the control of off-site migration.
The pulling effect of the perimeter wells, which are sited to
cover all areas of the boundary, should prevent LFG from
migrating off-site. However, the commenter is correct;
kli-85\04 2-120
-------
collection and control systems need to address off-site
migration. A provision has been added to $ 60.752 requiring
collection and control systems be designed to minimize
off-site migration of subsurface LFG.
In addition to requiring that migration be addressed in
each collection system design plan that is submitted, the
final regulation includes a new S 60.753 on collection system
operation. This section compiles various operational
provisions that had previously been located at different
points throughout the proposed regulation into one section. A
requirement to operate the collection system with a surface
methane concentration of less than 500 ppm, which is fulfilled
through the use of a surface monitoring device, has also been
included.
The provisions for the surface monitoring include a
requirement to monitor surface methane concentrations around
the perimeter of the collection area. This will further
ensure that offsite migration is controlled. These provisions
are applicable to all systems designed according to the
provisions of §§ 60.752 and 60.759 and systems which include
any alternatives to the provisions of SS 60.753 through 60.758
that have been submitted for review.
Comment: One commenter (IV-D-27) suggested that the
bentonite seal around the collection wells and the probes
should be placed at the cover/refuse boundary rather than 4 ft
above the gravel pack. The commenter argued that this would
reduce the chance of air intrusion.
Another commenter (IV-D-39) also asserted that the
proposed gas well design lacks a 1-ft thick bentonite seal
immediately above the crushed stone and that the crushed stone
has been found to be very important in preventing air
intrusion into the well. The commenter also stated that the
diameter of the well boring should be 0.61 to 0.91 m, which
allows for the use of larger diameter boring rigs, which are
used to install a leachate extraction well in the same bore
hole as the gas well.
kli-85\04 2-121
-------
Response: As a result of concerns such as those
expressed by these commenters, the prescriptive design
specifications for gas collection systems have been removed
and replaced with criteria for the design of such systems.
The design plans must meet the criteria in S 60.759 or
demonstrate equivalence, be prepared by a professional
• *
engineer, and approved by the Administrator (i.e. the State or
local agency that has been delegated authority).
The proposed design specifications were established to
*
provide an owner or operator a clear design to follow in lieu
of submittal of an independently-designed system. However,
since the regulation has been revised in S 60.759 to provide
criteria for sufficient collection systems which allow sources
to design collection systems in any manner they chose (as long
as the design plans are prepared by a professional engineer,
and are approved by the Administrator), wells of any diameter
may be bored, as long as the system is approved.
Comment; One commenter (IV-L-1) recommended that the EPA
require either a comparable collection efficiency for affected
landfills of all sizes or, for landfills located in
environments that prevent achieving the required numerical
efficiency value, minimum equipment specifications for the
collection system. The commenter (IV-L-1) suggested achieving
this by: restricting the lengths, type of materials and
techniques used to assemble the well points, seals, pumps,
compressors, dryers and collection systems; requiring minimum
commitments of resources, expertise and levels of effort to be
devoted to system maintenance; and further limiting the time,
provided in the proposed NSPS, after initiation of active
landfilling operations before which construction and operation
of landfill gas collection and treatment systems must take
place.
Response; These standards and emission guidelines are
promulgated under section 111 of the CAA, which requires the
standards be set based on the application of BDT considering
costs and any nonair quality health and environmental impacts
klk-85\04 2-122
-------
and energy requirements, at the time the standard is
promulgated. An NSPS establishes a nationwide minimum level
of control, but it is based on the application of BDT.
The commenter's concern regarding the collection
efficiency for affected landfills is a valid concern and has
been addressed by the EPA. The EPA considers surface emission
monitoring to be an appropriate tool for monitoring both cover
integrity and the effectiveness of well spacing and vacuum in
order to ensure adequate collection efficiency. Therefore,
*
surface emission monitoring has been incorporated in § 60.753,
where all of the operational provisions for the collection
system have been grouped together.
2.12.2 Determination of Well-Spacing
Comment; One commenter (IV-D-26 and IV-F-6) argued that
less restrictive design and operating parameters for LFG
control systems can be specified and yet still achieve the
desired emissions reductions. The commenter's particular
concern is the design criteria for wellhead spacing. The
commenter contended that under normal conditions, well head
spacing for central wells of 90 to 120 m is sufficient to
control surface emissions and lateral migration of LFG. The
commenter stated that at these distances a zone of negative
pressure builds beneath the landfill cap and will keep LFG
from escaping through the landfill cap. The commenter
contended that on occasion this spacing is inadequate due to
subsurface factors that restrict the movement of LFG and the
vacuum created by the wells. The commenter asserted that in
these areas, surface methane readings above 50 ppm can be
detected using surface measurements for methane. The
commenter agreed that closer well spacing is necessary where
this is clearly demonstrated.
Another commenter (IV-D-39) stated that the proposed
design specifications for well spacing assume that the
landfilled waste is homogeneous. The commenter noted that in
reality this is not true because the waste composition varies.
Because of the variable nature of the fill, the commenter
klk-85\OA 2-123
-------
supported a performance standard rather than a design
standard, and recommended that alterative designs be allowed
and encouraged.
One commenter (IV-D-30) questioned the use of ROI as
determined by the Method 2E pumping test. The commenter
asserted that Method 2E is comprised of unnecessary "leak
testing" which is more expensive and takes longer than other
methods.
One commenter (IV-D-26) contended that short term pumping
tests (for k calculation) do not yield accurate data and
provide no basis for sizing LFG collection systems. The
commenter stated that uncontrolled landfills have built up
landfill pressure and that initially, the test wells will show
higher flow rates than at true steady state. The commenter
asserted that with a full well field in place, 6 to 12 months
is required to reach steady state. The commenter contended
that no basic pump test, including the EPA's proposal, is
reliable and will invariably overestimate the quantity of gas
generated.
The commenter (IV-D-26) stated that they have solved the
pump test problem by designing gas extraction systems so that
the blower compressor has the ability to produce a minimum of
13 to 25 cm of water column vacuum at the most remote point in
the header/lateral system. Friction loss is controlled by
allowing only a 2.5 cm water column pressure drop per 30.5 m
before pipe diameter is increased. The commenter (IV-D-26)
stated that this allows the gas extraction system's ability to
collect gas to be the controlling factor, not a "guess" at the
landfill's ability to produce gas.
One commenter (IV-D-26) contended that Method 2E assumes
a uniform, isotropic, fully developed, concentric vacuum
pattern around the well, however, this does not occur in
actual practice. The commenter stated that it is entirely
predictable that a 50-acre landfill with an HDPE cap and 0.9 m
final cover can be covered by a single vertical gas well.
klk-85\04 2-124
-------
Another industry commenter (IV-D-27 and IV-F-5) urged
that greater flexibility be allowed in establishing the area
of influence used for well-spacing. The commenter (IV-D-27)
suggested that engineering equations are just as effective for
calculating the area of influence and are much less expensive.
The commenter requested that engineering equations be allowed
in lieu of Method 2E testing for establishing the* area of
Influence. Two commenters (IV-D-25, IV-D-34) agreed that
Method 2E is only one of several methods that can be used as a
guide for* gas collection design.
One commenter (IV-D-27) faulted the three methods
provided in the proposal/ noting that two of them are based on
expensive field testing procedures, and that the third is
based on theoretical modeling utilizing only two site-specific
values. The commenter suggested that experts in the field
could better determine an effective area of influence.
One commenter (IV-F-4) faulted area-of-influence methods
of determining the well spacing because these methods have
been demonstrated primarily at large landfills and may be
misleading or inappropriate for all sizes of landfills. The
commenters (IV-D-25, IV-D-34) also stated that Method 2E would
result in an overly large area of influence in deep landfills,
causing the system to miss as much as 85 percent of the LFG.
One commenter (IV-D-26) recommended that all references
to radius of influence and Method 2E be deleted and be
replaced with the general recommendation that the LFG
extraction system be designed by a competent and qualified
registered professional engineer and that such plans be
submitted and approved by the local regulatory agency.
Another commenter (IV-F-6) stated that Method 2E is not
necessary to determine the area of influence; it is only
necessary to determine if there is no gas in the perimeter
monitoring probes and that there is less than 50 ppm methane
in the surface emissions.
Response; In response to the many comments requesting a
simpler approach for determining the area of influence for
klk-85\0* 2-125
-------
purposes of collection system spacing, the EPA has removed the
specific methods for determining ROI or any other area of
influence determination from the requirements of the
regulations. Instead, as mentioned earlier, the final
regulations require a professional engineer to prepare
collection system design plans with gas collection systems of
• %
sufficient density to achieve uniform control of surface gas
emissions and address gas migration.
Method 2E is no longer required, but can still be
•
performed to determine the appropriate area of influence for a
given landfill. Method 2E has been used before and generates
useful data (see Docket No. A-88-09, Categories II-C and II-D
and the response in section 2.11.2 for further discussion of
the development of Method 2E). The EPA developed Method 2E
with input from industry representatives. Industry provided
experience on techniques that the EPA then developed into
Method 2E. The EPA believes that Method 2E can be used
effectively to estimate the area of influence.
As mentioned in previous responses, quarterly monitoring
of the surface methane concentration has also been added to
the rule to help ensure cover integrity and effectiveness of
well spacing.
Comment; Three commenters (IV-D-30, IV-D-39 and IV-F-3,
IV-F-4) stated that the curves prescribed in the regulation
for use in well spacing, which are based on landfill depth and
blower vacuum, are not field-tested curves and will result in
wells spaced too closely. In addition, the commenter
(IV-D-39) remarked that the graph entitled "Estimated radius
of influence as a function of blower vacuum" needs to account
for pressure drops associated with header losses in the
piping.
One commenter (IV-D-26 and IV-F-6) stated that "radius of
influence" is a relative term with little actual meaning,
because the calculations are theoretical and have not been
reliable for predicting actual flow conditions in the real
world. Another commenter (IV-D-55) contended that a simple
klk-85\OA 2-126
-------
mathematical formula that can be used on all landfills for the
placement of collection wells does not exist.
Another commenter (IV-D-7) suggested that the proposed
method of calculation for the spacing of gas wells and vacuum
contradict the commenters experience and should be revised.
The commenter claimed that wells have been spaced at much
• *
greater distances within landfills with no air infiltration
and that well spacings of 46 to 76 m can be operated
successfully. The commenter recommended that landfills be
•
allowed to use greater well spacing if they can demonstrate
collection of 80 percent of the calculated or Method 2E
measured gas production.
Response: The EPA determined that the curves given in
the proposal regulation did not adequately address field
situations. The curves were developed using theoretical
methods and did not have all of the many factors influencing
radius of influence factored into them. The curves were
removed from the regulation. The regulation no longer
specifies the method that must be used to determine the area
of influence for well spacing.
The EPA determined that a performance based standard for
collection systems was not feasible to prescribe and enforce,
and that a collection system meeting the criteria in S 60.759
(or equivalent) represents BDT (See section 2.7). Eighty
percent collection of the Method 2E measured gas production
would not be equivalent in all cases and is not a feasible
format for the standard. The BDT for controlling LFG was
determined to be a well-designed collection system routed to a
control system achieving 98 percent reduction of NMOC. A
landfill owner or operator can use any method they choose for
determining the sufficient density of their collection system,
as long as the system meets the criteria provided in S 60.759
and is submitted to the Administrator for review. In
addition, surface emission monitoring provisions have been
incorporated into the final regulation to ensure adequate
collection of LFG.
2-127
-------
2.13 OPERATIONAL STANDARDS
Comment: Three commenters (IV-D-27, IV-D-39, IV-F-6)
contended that the regulation was overly specific in requiring
the use of an orifice meter to measure gas flow rate at the
collection header, and argued that other devices, such as
pitot tubes and texture flow tubes would be just as effective.
Response: The orifice meter referred to in the proposed
regulation is just one device used to measure gas flow. Other
types of flow measurement devices may be used in its place.
*
Regardless of the type of meter used, the meter must be
calibrated using the procedures outlined in section 4 of
Method 2, appendix A to 40 CFR part 60.
Comment; One commenter (IV-D-7) suggested that the
process to be used for correcting for excess air intrusion
around the well-head should be left to the discretion of the
owner or operator. The commenter further stated that the
current language of the proposed regulations seems to
discourage methods of adjustment (increasing blower speed,
repairing leaks, etc.) other than those in the proposal.
A second commenter (IV-D-29) warned that issues such as
LFG leaks in equipment, air emission aspects of storage, and
treatment of leachate and/or condensate were not addressed
under the proposed regulation. This commenter provided
information on how their State addressed these issues.
Another commenter (IV-D-55) also pointed out that various
additional operational criteria are needed, such as
flame-outs, pipe leaks, landfill movement, air injection,
sampling ports, etc.
One commenter (IV-D-55) recommended that the design
standards require the installation of backup fuel supplies to
maintain minimum combustion temperatures and ensure proper
combustion of the NMOC and toxic air contaminants.
Response; The final regulation has been revised to
incorporate the suggested flexibility for correcting excess
air intrusion. Any method can be used to correct for excess
air intrusion as long as it does not adversely affect the
kUt-85\04 2-128
-------
integrity of the gas collection system, or the ability or
effectiveness of the gas collection system to collect landfill
gas.
The treatment of leachate and condensate is addressed
under RCRA (subtitle D). Landfill gas leaks in equipment and
air emissions from storage were not part of the f^ocus of this
NSPS. It is assumed, however, that operable and well
maintained equipment will be used which will reduce air
emissions, through leaks in equipment.
Requirements for downtime caused by equipment
malfunction, flame outs, pipe leaks, etc., have been added to
the regulation (see section 2.14.2, System Shutdown). All
combustion devices are required to pass a performance test
and/or monitor parameters to ensure proper operation. Some
devices may need auxiliary fuel to meet these requirements and
other devices may not. The EPA considers these requirements
to be adequate without mandating backup fuel.
Comment; One commenter (IV-D-27) requested that the
regulation should clearly discuss the subject of pressure at
the wellhead during start-up, since some systems do have
positive pressure at the wellhead during the start-up phase.
Another commenter (IV-D-55) recommended the requirement
to have negative wellhead pressure requirement be eliminated
and a performance standard for all points on the surface of
the landfill be established. The commenter stated that LFG
generation typically surges about 2 weeks after a rainfall
which causes the pressures in the collection wells to be
positive. The commenter also stated that the negative
pressure requirement limits the operations ability to shutdown
part of the collector's system (see section 2.14.2, "System
Shutdown," for more detail on this comment).
Another commenter (IV-D-39) asserted that the requirement
to have negative pressure at the gas collection wellhead
cannot always be met because a well may be overstressed or may
be experiencing condensate problems, and, therefore, may need
to be cut back. Also, the commenter stated that immediate
kl*-65\04 2-129
-------
installation of an additional well is not always permissible
under State law. The conunenter recommended that a minimum
90-day time period over which a well can be brought back into
compliance be incorporated in order to satisfy the negative
pressure requirement. The commenter also recommended that,
instead of requiring installation of a new well, that the
regulations allow an owner or operator to restore a well's
function, require the owner or operator to submit a plan to
the State for correcting the function if not restorable, and
to require the operator to comply with such a plan once it is
approved by the State.
One commenter (IV-D-7) stated that the requirement to
install an additional well if negative pressure cannot be
achieved through valve adjustment at the wellhead is vague. A
second commenter (IV-D-27) suggested that a time schedule
needed to be added to the provisions for installing additional
wells when a negative pressure at all wells cannot be
achieved. The commenter said that in some States, a lengthy
permit process is required before installing additional wells,
and further noted that sometimes specific wells actually need
to be removed from a system, although no reasons for such
removal were provided.
Response; In the interim between proposal and
promulgation, the EPA sought to improve the provisions of
these regulations regarding both maintenance of negative
pressure at the wellhead, and the addition or replacement of
wells. As mentioned in the previous response, any operational
adjustments the operator can make to restore the well to
proper function are not precluded by these regulations.
After initial installation of the collection system,
owners and operators will be expanding the collection system
over time to provide adequate coverage for all areas in which
waste has been deposited for 2 years if the area will be
closed or at final grade, or 5 years if the area is still
active. In the case of system expansion, the EPA assumes that
landfill owners and operators will include these wells in
klk-85\04 2-130
-------
their overall management scheme, including interaction with
State authorities, as necessary, to allow timely installation.
Given that these wells are added by design, the NSPS requires
that they be installed within 60 days of the waste reaching
the specified age (2 years for closed areas, 5 years for
active areas). The 60 days were included, even though the
•»
installation is likely planned and materials ought to be
on-site, to allow for potential delays due to weather or
availability of drilling rigs, which are often hired under
•
contract.
The final regulations now provide three exceptions to the
requirement for negative pressure at each wellhead. The first
is the occurrence of fire or a significant increase in well
temperature. In this case, the owner or operator must report
the positive pressure occurrence in the annual report. The
second exception is if the source uses a geomembrane or
synthetic cover. If a geomembrane or synthetic cover is used,
the owner or operator must develop and include acceptable
pressure limits in the design plan. The final exception is
when a well is decommissioned to accommodate for declining gas
flows. In this case the well may experience static positive
pressure after shutdown, as long as the changes made to the
system are incorporated into the design plan and approved.
There are two cases in which wells must be added that
were not included in the design plan: when negative pressure
cannot be restored at a given wellhead within 15 days
(exceptions noted above), and when surface methane levels of
500 ppm or more have been recorded at a location 3 times
within a quarterly monitoring period. In the first case,
15 calendar days are allowed to restore negative pressure at
the wellhead and thereby avoid installation of an additional
well. The principal reason positive pressure is likely to
occur is that the collection system capacity in the locale of
the well is less than the production in the locale. Either
capacity can be increased through adjustments to the vacuum,
or system expansion is warranted. If adjustments are
klk-85\04 2-131
-------
adequate, the pressure recorded at the next required
monitoring (15 days) should be negative. The 15 days allows
time for a surge in generation after significant rainfall to
subside, as mentioned by commenter IV-D-55. This also allows
time to resolve the problems mentioned by commenter IV-D-39.
If negative pressure cannot be restored within this 15-day
• %
period, and the area is producing more gas than the system in
that area is able to handle, then the installation of an
additional collection device within 120 days is warranted.
Also, if rainfall results in increased generation on a regular
basis, additional capacity is also warranted.
In the case when methane concentrations are monitored at
500 ppm or more, two 10-day monitoring periods are allowed to
reduce methane concentrations below 500 ppm. There are two
reasons likely to contribute to excessive methane levels:
cover failure, or ineffective area of influence at the
adjacent wells. When excessive methane concentrations are
recorded, 10 days are allowed for personnel to evaluate the
problem. If the cover has been disturbed, maintenance will
likely reduce surface levels of methane. On the other hand,
if the area of influence is ineffective for the gas production
level in the vicinity, adjustment of the vacuum may extend the
effective area of influence, and cause methane concentrations
to decrease. An increase in vacuum cannot always be used,
however, because there is a trade-off between increasing the
vacuum and avoiding excessive air infiltration.
If a second exceedance occurs, the location must be
remonitored within 10 days. If the methane concentration
meets or exceeds 500 ppm three times within a quarterly
monitoring period, the source must install an additional
collection component within 120 days of the original
exceedence. Therefore, if the vacuum is increased as much as
possible without excessive infiltration, and the third
monitoring of surface methane concentration still reaches or
exceeds 500 ppm, installation of an additional well is
warranted.
kli-85\04 2-132
-------
Because disturbance of the cover can coincide with an
ineffective area of influence, the EPA has allowed an
additional 10 days after the occurrence of the second
exceedance. The EPA believes it would be possible for
landfill personnel to locate and repair cracks or other flaws
in the landfill cover that were detected after an exceedance
• %
was recorded. Such exceedances may have resulted, at least in
part, from an ineffective area of influence. If this occurs,
excessive methane concentrations may be monitored in the
subsequent monitoring period in spite of the repairs to the
cover. In this case, an adjustment to the vacuum at adjacent
wells may still restore surface methane concentrations to
acceptable levels. Therefore, 30 days are allowed to attempt
to reduce surface methane concentration to below 500 ppm
before the installation of an additional well would be
required.
In both cases of unscheduled system expansion (i.e., when
negative pressure cannot be maintained or when methane
concentrations exceed 500 ppm), 120 days are allowed for the
installation of the required well or other collection device.
More time is allowed than for scheduled expansions because the
availability of materials, drilling rigs or contract personnel
on short notice is less certain.
Comment; One commenter (IV-D-19) warned that a variety
of operational considerations may affect the installation and
operation of collection and control systems. The
considerations the commenter mentioned were: equipment
traffic, settlement of landfill cover surfaces, effects of
bailed waste, changing topography, weather, barometric
pressure, on-site structures, gas generation rate, maintenance
and repair, and existing passive venting systems.
Response; The EPA agrees that these considerations will
have an affect on the installation and operation of collection
and control systems, as they do with many systems in various
industries. All of these considerations, however, vary from
site to site, and are best addressed by the local operator.
2-133
-------
The final standards have been revised to require owners and
operators to submit site-specific design plans, prepared by a
professional engineer, to the Administrator for approval.
2.14 COMPLIANCE
Comment; One commenter (IV-D-45) stated that all
landfills should be addressed under the proposed regulation
and requested provisions allowing coordinated emission control
between new and existing landfills within close proximity to
each other.
Response; The regulations require that the control
device used for either new or existing landfill emissions be
demonstrated to achieve 98 weight-percent efficiency.
Co-control among landfills is allowed as long as
98 weight-percent efficiency is achieved. However, the EPA
does not plan to promulgate specific provisions to address
co-control among landfills. Furthermore, not all landfills
require control. See section 2.4.1 for rationale for the
selected design capacity and emission rate cutoffs.
Comment; One commenter (IV-D-7) indicated that they had
designed a gas collection well equipped with a 48-in diameter
well from the bottom up beginning at the liner level, and the
commenter questioned whether this successful design would be
allowed under the proposed regu-ition. The commenter
indicated that the proposed regulations will be a burden on
landfills with active gas collection systems already
installed. The commenter suggested exempting these landfills
under the BDT definition or else exempting them if they are
below the EPA's proposed significance level of 40 tons/yr of
NMOC.
Response: Specific prescriptive designs have been
eliminated from both the NSPS and the EG, and a design plan
meeting the conditions of S 60.752(b)(2)(i) or S 60.33c(b)
must be submitted to the Administrator for approval. Thus, as
long as the system meets the criteria in the rule and the
design plan is approved, a well of any design may be included.
kli-85\04 2-134
-------
For an existing system, the owner or operator may
continue to use the existing system as long as the system is
effectively collecting LFG from all gas producing areas of the
landfill, and negative pressure can be maintained at each
wellhead without excess air infiltration. Quarterly
Monitoring must also show surface methane concentrations below
500 ppm. The adequacy of the system must be demonstrated to
the State regulatory agency.
Collection and control systems are required only if the
*
landfill design capacity exceeds 2.5 million Mg or
2.5 million m3 and the annual NMOC emissions exceed 50 Mg/yr,
calculated by procedures specified in the rule. Landfills
below these cutoffs do not need to submit a collection system
design plan or install a system.
Comment; One commenter (IV-D-2) stated that collection
systems have been estimated to be 60-percent efficient on
average, and that landfills near residential areas should be
required to have a 95 percent efficient collection system and
a 99.99 percent efficient treatment system.
One commenter (IV-D-19) stated that a 98 weight-percent
effective gas collection system efficiency is often not
achieved because of variability of gas generation,
decomposition rates, and gas distribution resulting in
efficiencies of 40 to 80 percent. Therefore, they suggested
that the regulations reflect that existing gas control systems
in place at established landfills should be allowed to
continue operation if they collect gas at a reasonable rate.
Response; The 98 weight-percent referred to in the
regulation is a 98-percent reduction of collected emissions
not a 98 percent emission collection efficiency. A percent
reduction standard is not specified for gas collection systems
because it is difficult and impractical to quantify the
performance of a gas collection system. Therefore, a design
and work practice standard has been set for gas collection.
Site-specific risk factors such as location are not addressed
by the NSPS program which is intended to provide uniform
klk-85\0<. 2-135
-------
national minimum standards based on BDT. State and local
programs can address site-specific problems.
2.14.1 Compliance—Schedule
Comment; Several commenters (IV-D-19, IV-D-20, IV-D-27,
IV-D-29, IV-D-56) contended that more time would be required
to come into the various phases of compliance. One commenter
(IV-D-56) requested that additional time be allowed in order
to spread out the costs of designing and installing the
control system. Another commenter (IV-D-19) said
administrative delays at municipally run landfills, such as
mandatory requirements to obtain competitive bids before
ordering equipment, may often warrant more flexibility in the
time schedule.
Another commenter (IV-D-27) anticipated that there would
be significant delay in adequate review and approval of
submitted designs, due mostly to lack of expertise with LFG
collection system design within the State offices. The
commenter recommended that owners and operators experiencing
such delays should be granted an extension on the time allowed
for installation of the system, rather than being required to
install the system prior to approval in order to meet the
1-1/2 year deadline within the proposed regulation.
Another commenter (IV-D-17) was concerned that the
technical expertise needed to meet the requirements of the
regulation are beyond most of the municipal landfill operators
capabilities.
One commenter (IV-D-32) questioned whether
S 60.752(b)(2)(ii) of the proposed rule, which requires the
installation of a collection and control system within
1-1/2 years of submittal of a design plan or notification of
intent, refers to the final or initial stages of installation.
Furthermore, the commenter stated that the time period of
1-1/2 years may be too lengthy. The commenter recommended
that the time period be reduced to 1 year if the design plan
submitted is modeled after the specifications and 6 months to
begin the installation of a collection and control system.
klk-85\04 2-136
-------
One commenter (IV-D-39) suggested that the requirement
that gas collection systems be installed at landfills not
meeting the proposed 150 Mg/yr emission rate cutoff within
30 months of the effective date of a State emission standard
be changed to allow for the phasing in of the program based on
calculated NMOC emissions at each landfills. The commenter
•»
provided an example in which landfills with emission rates
greater than 300 Mg/yr could be required to be in compliance
within 30 months, those with rates at or between 200 and
300 Mg/yr could have 48 months, and those with less than
200 Mg/yr could have 5 years. The commenter maintained that
this phased approach would allow the regulatory burden to be
spread out, since only a limited number of qualified
contractors exist to perform the work and would target the
efforts of the regulatory agency on those facilities with the
greatest impact on the environment.
One commenter (IV-D-45) requested that the proposed
period of 1 year to submit notification of intent to install
collection and control systems be reduced to 3 months.
Response; As was explained in the proposal preamble, the
EPA has established the compliance times for the submittal of
the notice of intent to install a collection system designed
in accordance with proposed S 60.758, now § 60.759, for review
on the assumption that all site-specific testing that could be
performed to exempt the landfill from control would be
performed. A 3-month period between exceeding the regulatory
cutoff and notification or plan submittal, as recommended by
one commenter, would not be sufficient for those owners and
operators electing to perform site-specific testing to verify
that the regulatory level has been exceeded or demonstrate
that emissions are below the regulatory cutoff. Although the
EPA does not believe that all owners and operators would
perform all the site-specific testing, it does not want to
penalize those owners and operators who commit to install a
system based on the earlier, more conservative, tier
calculations either.
kli-85\04 2-137
-------
As was also discussed in the proposal preamble, the EPA
expects that owners and operators would likely consult vendors
and suppliers at the time of system design, which occurs
within the first year after the regulatory cutoff is reached.
This leaves an additional year and 9 months for the resolution
of permitting difficulties. In the case of new MSW landfills,
• x
the EPA recommends that the initial permit include provisions
addressing the installation of a collection system, should it
become necessary.
In the case of existing MSW landfills, the first NMOC
emission rate report would be submitted 90 days after
promulgation of the State emission standard. The States will
be required to submit their plans for Agency review and
approval 9 months from promulgation of the final EG. The EPA
must approve or disapprove the State plan within 4 months of
submittal. Therefore, more than a year will likely pass
before an existing MSW landfill would submit an NMOC emission
rate report. Owners or operators of existing landfills might
elect to perform the Tier 1 calculation ahead of time, in
order to evaluate what future requirements might apply to the
existing landfill. Finally, if permitting or other
administrative hurdles cannot be overcome in a timely manner,
the State may provide a longer compliance schedule pursuant to
the provision of S 60.24(f)(3), based on "other factors
specific to the facility (or class of facilities) that make
application of a less stringent standard or final compliance
time significantly more reasonable" (emphasis added).
Comment; One commenter (IV-D-21) recommended that
5 years be given for control compliance for energy recovery,
instead of 3 years, because of the additional commercial and
regulatory considerations.
Response; As provided in the regulation, the EPA feels
that 3 years is adequate to install a collection and control
system. No special provisions will be provided to use an
energy recovery system. Using an energy recovery system is at
the discretion of the landfill owner/operator and is not
kLk-85\04 2~138
-------
required by the regulation. An energy recovery system can be
installed at a date after an initial control system is
installed, but it is at the discretion of the landfill
owner/operator and is not required by the regulation.
Comment: Two commenters (IV-D-18, IV-D-45) proposed that
landfills close to exceeding the regulatory emission rate
cutoff should not be allowed to accept additional waste until
the collection and control system has been approved (IV-D-18)
or installed (IV-D-45).
Response: The EPA views the regulatory emission rate
cutoff as a threshold initiating the process of system design
and installation, rather than a limit above which an
unacceptable risk exists. This is why a landfill is
considered to be "controlled" once a design plan has been
submitted. The EPA recognizes that the process of system
design and installation takes time, but does not agree that
prohibiting waste acceptance until system approval and
installation is warranted, as long as the owner or operator is
proceeding through the process.
2.14.2 Coropliance--System Shutdown
Comment; One industry commenter (IV-D-27) recommended
that integrated surface sampling be required during collection
system shutdown to demonstrate "safe" surface emission levels.
The commenter further recommended that owners and operators be
required to keep records on each of these events.
A second commenter (IV-D-55) recommended that all flare
systems be required to have automatic blower shutdown and
valves to instantly stop the flow of LFG to the flare when
there is a flame-out. The commenter also recommended that
flares be required as backup systems where energy recovery
systems are installed because downtime is more frequent with
turbines and I.e. engines.
The commenter also stated that the negative pressure
requirement limits the operator's ability to shutdown part or
all of the collection system on a temporary basis for
2-139
-------
maintenance, repairs, and changes in gas flow (see also
section 2.13, for more detail on changes in gas flow rate).
Response; In response to these commenters, the EPA has
provided specific provisions regarding system start-up,
shutdown, and malfunction in 5 60.755 of the final NSPS which
reads as follows:
• *
"(e) The provisions of this subpart apply at all
times, except during periods of start-up, shutdown,
or malfunction, provided that the duration of
start-up, shutdown, or malfunction shall not exceed
5 days for the collection systems, and shall not
exceed 1 hour for treatment or control devices."
The various provisions recommended by the commenters were
considered; however, the EPA wanted to avoid adding provisions
that are not directly linked to compliance. Compliance with
the standards for collection systems is the installation and
operation of a properly designed system. The surface emission
limit added as part of the surface emission monitoring was
included under the operational standards. The EPA is using it
to verify that the system is adequately operated and
maintained, and not to ensure an emission limit, surface or
otherwise, as normally required under section 111. For
example, surface sampling may demonstrate that emission levels
are increasing when the collection system is shut down, but a
shut-down system cannot possibly meet a standard requiring
that a collection system be actively collecting LFG.
Therefore, in this case, getting the system back on line is
the primary concern.
The 5-day period for collection systems was selected in
recognition that a major problem with a collection system will
likely take longer than an hour to locate and solve but also
that the landfill is not going to stop generating LFG.
Localized problems with crushed pipes, etc., may be resolved
through adjustments to the draw from other wells in the
vicinity until repair is effected. If the blowers need to be
repaired or replaced, the collection/control system may be
able to function temporarily as a passive system while repairs
klk-85\0
-------
are effected. However, the EPA has no data upon which to base
how long such an arrangement would be feasible. Therefore,
owners and operators should take care to plan for such
contingencies. A 5-day initial attempt at repair has been
required in other regulations requiring that VOC-laden gas be
routed to a control device. Absent any clear data to support
a different time-period, the EPA has adopted that repair
period for this NSPS.
Similarly, requiring a backup flare when an energy
recovery device is used for control is one method of ensuring
that LFG can be routed to a backup device while such systems
are down. It could be argued that backup flares should also
be required for those sites electing to use flares for
controls. In practice, however, most sites currently
collecting landfill gas have multiple control devices, whether
multiple flares, i.e. engines or turbines or combinations of
the above. Therefore, only a short period of time would be
necessary to relight a flare or reroute the collected gas to
an alternative device. For purposes of these regulations, the
issue is that the gas is routed to a control device, not what
specific provisions the owner or operator has made to ensure
that control is achieved. Whether the owner or operator has
arranged with vendors for quick turnaround on replacement
parts, has spared system components on site, or has multiple
devices on line so that the flow may be distributed among
them, compliance may be maintained without the EPA specifying
a particular strategy. Therefore, the EPA has elected to
specify a downtime that is acceptable under these regulations,
and leave the strategy on how to comply to the owners and
operators to negotiate with the appropriate regulatory agency.
After consideration of the comment regarding automatic
blower shutdown, the EPA has included provisions requiring
that the gas mover system be shutdown and all valves to the
collection and control system closed whenever the control
device is inoperable. The provisions also require that the
control device be operated at all times when LFG is routed to
kik-85\o« 2-141
-------
the device. Again, in an effort to avoid requiring that
landfill owners and operators comply with the NSPS in only one
of many alternative means of compliance, the EPA is not
requiring that this be accomplished through the use of
automatic devices. While these devices may be appropriate in
many cases, there may be very small systems that could be just
as easily shut down manually. If landfill emissions were
routed to the atmosphere through the collection and control
system for some portion of an hour, this would still be a
•
relatively small emission event.
2.14.3 Compliance—System Expansion
Comment; One commenter (IV-D-17) stressed that requiring
gas collection in areas that continue to accept waste is too
costly for operators because these collection systems will be
deserted within a short time after the area reaches capacity.
The commenter suggested that only those parts of a landfill
which have received the final cover should be required to
install emission controls. Another commenter (IV-D-29) stated
that the criteria for installing wells should be based on
emission potential in a given area rather than a 2-year
requirement.
A third commenter (IV-D-22) added that it often takes
more than 2 years for a given area to achieve final grade and
to be closed with the application of a final cover. The
commenter said that the appropriate time for installing wells
needed to be determined on a site-specific basis. The
commenter asked if "area" was defined.
Three commenters (IV-D-20, IV-D-29, IV-D-39 and IV-F-3)
advised that the 2-year time frame requirement for installing
extraction systems is not reasonable and/or does not appear to
coincide with common operational practices at MSW landfills.
One of the commenters (IV-D-20) recommended that all landfills
be required to achieve final grades in a given phase as soon
as possible and to close those portions thereof annually. The
commenter further recommended that the owner or operator be
required to incrementally extend the extraction well field to
klJt-85\04 2-142
-------
all recently closed areas every 2 years after filling begins
in a phase. Another of the commenters (IV-D-29) said control
in an active landfill should be determined by specific
criteria instead of a time limit.
One commenter (IV-D-27) requested that owners and
operators be allowed the flexibility to demonstrate that
additional wells are not necessary due to low gas production
levels in a given area, and not have to install additional
wells within 2 years of waste deposition, as required by the
proposed regulation. The commenter suggested that greater
clarity about when collection must commence in each new cell
is needed.
Response; As a result of further analysis in response to
commenters' concerns, the EPA has modified the final NSPS to
require installation of wells or other collection devices
within 60 days of the date in which the initial solid waste
has been in place for a period of 2 years or more for areas
closed or at final grade, or 5 years or more for active areas.
The 5 year period is believed to be more reasonable and
consistent with common landfill practices than the proposed
2-year period for active areas of the landfill. Landfill
areas are typically active for more than 2 years. If
collection system wells were required for all areas within
2 years, they would likely be covered over. The covering of
these wells would either decrease their operational life, or
require extension of the well upward, significantly increasing
costs. A period longer than 5 years is not allowed because
emissions from a given block of waste will decline over time,
so it is important to install collection and control systems
as soon as reasonably practical. For areas that are closed or
at final grade, collection systems must be installed within
2 years, as at proposal.
The final provisions allow the exclusion of
"nonproductive" areas in § 60.759(a)(3)(ii). This provision
may be used to exclude areas from control, so long as the
aggregate emission potential of all areas excluded under this
kUc-85\04 2-143
-------
provision is less than 1 percent of the landfill's overall
emission potential. (Segregated areas of asbestos or
nondegradable waste nay also be excluded and are not subject
to the 1 percent criteria.)
As discussed in chapter 3 and appendix D of the proposal
BID (EPA-450/3-90-011a), the gas generation rate model used in
• >
the development of these regulations assumes that after a
negligible lag time, the gas production rate is at its peak
for a discrete mass of waste, and decreases exponentially
•
thereafter as the organic fraction of the refuse decomposes.
Although the lag time is characterized as negligible,
according to the gas generation rate model used, it can vary
from several weeks to a few years. This peaking rate followed
by rapid decline is the basis for the 2-year collection
requirement at closed areas. The 5-year period for active
areas was added to be in keeping with current operational
practices at MSW landfills and to reduce costs and
inefficiencies that would be associated with installing wells
in active areas and then covering them over as more refuse is
deposited. The EPA considers this 2-year/5-year split a
common sense approach to ensure that all gas producing areas
are being appropriately controlled.
Since the calculation of the overall emission rate
involves summing the emission rate from each yearly submass of
refuse, and the rates will vary inversely with age, the
maximum production from an area for purposes of these
regulations will occur close to the time of its deposition,
and its contribution to overall emissions will decline
continuously thereafter. It is important, therefore, to
install collection wells into refuse as soon as possible.
The same calculation that establishes overall emissions
can be used to calculate emissions from discrete segments of
waste, provided that the age of the refuse is known. Since
the model takes into account the age of the refuse,
theoretically, the individual annual fills can be ranked by
klk-85\04 2-144
-------
productivity and the least productive excluded from control
(up to l percent of total emissions).
It is important to note that the exclusion of refuse from
collection does not extend to the determination of
applicability. All waste present in the entire landfill must
be included in the calculation of the overall NMOC emission
•»
rate for purposes of determining whether gas collection and
control is required, except for segregated, documented masses
of nondegradable refuse such as cement or nondegradable
*
demolition wastes.
2.15 RECORDKEEPING AND REPORTING
Comment; Several commenters (IV-D-17, IV-D-27 and
IV-F-5, IV-D-36) requested that the EPA provide additional
clarification about the reporting and recordkeeping
requirements. Three commenters (IV-D-20, IV-D-27, IV-D-36)
said that the reporting and recordkeeping requirements were
too administratively burdensome. One of the commenters
(IV-D-27) contended that the recordkeeping and reporting
provisions of the proposed regulations were too burdensome to
the State agencies responsible for reviewing them and that
annual instead of semiannual submissions should be required.
The commenter also suggested that greater clarity about the
various elements necessary in each report is needed. However,
three commenters (IV-D-36, IV-F-5, IV-F-6) proposed that if
the reporting and recordkeeping effort was in support of data
base development, even landfills below the proposed design
capacity exemption should participate.
Response: The recordkeeping and reporting requirements
of the NSPS include only those records and reports necessary
under the provisions of section 111 to verify applicability
under or exemption from the standards, that control equipment
is properly operated and monitored, and to verify compliance.
The design capacity report alerts the regulatory
authorities to the presence of a landfill subject to the
standard, whether or not that landfill is subject to control.
The NMOC emission rate reports track the increase in emissions
klk-85\04 2-145
-------
at subject landfills and indicate when control will be
necessary. The closure report is necessary to indicate that
either an uncontrolled source will never be subject to
control, or that removal of controls at a controlled source is
approaching. The equipment removal report allows the
authority to review the basis for equipment removal and to
• %
verify that all three criteria are met.
The purpose of the proposed semiannual report was to
verify that the collection and control system was operated in
•
compliance with the standards and to provide information on
the frequency and duration of noncompliance periods. The
regulations list the information to be included in each
report.
After considering the comments and the Agency's
initiative to reduce recordkeeping and reporting burdens, the
frequency of the semiannual report has been changed to annual.
By reducing the frequency, the cost burden of generating
reports will be reduced. Information on noncompliance periods
will still be reported within a year of their occurrence,
which is sufficient to allow timely enforcement of the rule.
An annual reporting period is consistent with other NSPS and
with the Title V permit program requirement for annual
compliance certification.
All of the records required under the NSPS are necessary
so that the design, installation, and performance of the
system can be shown to comply with the NSPS. The reports
submitted by landfills above the design capacity exemption
provide substantial amounts of data for review. Requiring
calculation of emission rates and reports by MSW landfills
below the design capacity exemption would be an unwarranted
burden and is not necessary to ensure that the regulations are
met.
Comment: Two industry commenters (IV-D-27, IV-D-32)
requested that the EPA clarify the information required for
the closure report referenced in S 60.756 of the proposed
NSPS. The commenters also said that the compliance report
klk-85\04 2-146
-------
required in § 60.756(e) of the proposed NSPS only addresses
vertical well systems, and needs to be expanded to cover any
approved design, such as is allowed in S 60.752.
Response: The closure report in § 60.757 of the final
NSPS must certify that waste deposition has ceased at the
landfill, and that additional waste deposition will not occur
without permit modification as described under S 60.7(a)(4).
Since the gas-generation model used results in a decreasing
NMOC emission rate for each unit of landfilled waste over
time, once waste deposition has ceased, the calculated NMOC
emission rate would continually decrease after closure.
In response to the commenters concern about compliance
reporting for alternative designs, the EPA reanalyzed the
requirements. The final rule no longer provides specific
design specifications. Instead, it provides criteria for
active gas collection systems (see § 60.759). Design plans
for systems meeting these criteria must be prepared by a
professional engineer and approved by the Administrator. In
addition, S 60.752(b)(2) of the final rule allows for design
plans for collection and control systems that do not meet the
criteria in § 60.759. These provisions will allow use of any
type of active or passive system as long as it meets the
general criteria in S 60.752(b)(2) and an adequate design plan
is submitted and approved. In addition to design information,
design plans must include any alternatives to the operational
standards, test methods, compliance procedures, monitoring,
recordkeeping or reporting provisions and a demonstration to
the Administrator's satisfaction of the equivalency of the
alternative provisions.
qppment; One commenter (IV-D-18) suggested that if it
appears that at any time in the future a landfill will meet
the proposed emission rate cutoff of 150 Mg/yr and a
collection and control system will need to be installed, then
a notification of intent to install a collection system should
be submitted immediately.
kli.-85\OA 2-147
-------
Response: The notification of intent to install a
collection or control system design plan must be submitted
within 1 year of the report of the determination that the
emission rate exceeds 50 Mg/yr. The timeframe for submittal
of the design plan was developed after careful consideration
of typical testing and reporting intervals, and w%ith a
sensitivity to the variability inherent in landfill
operations.
Land.fill emissions vary substantially over time.
Designing collection and control systems requires considerable
resources, and design plans should not be required unless it
is evident that control will actually be required. Waste
acceptance rates, landfill practices, and local regulations
change frequently enough that a design plan that seems
appropriate today for a need anticipated in the future may
actually be infeasible when the time comes to install. In
some cases, waste acceptance rates may even decrease resulting
in lower emissions than predicted. For example, rates might
decrease if a given community were to prohibit the acceptance
of yard waste. Some landfills may close down before the
anticipated emission rate is reached. The EPA is not prepared
to require landfill owners and operators to expend resources
developing a collection and control plan before it is
reasonably certain that the system will, in fact, be required.
Comment; Three commenters (IV-D-20, IV-D-51, IV-D-54)
argued that the proposed 100,000 Mg design capacity exemption
for reporting requirements is too low in relation to the
proposed 150 Mg/yr rate of NMOC emissions required to install
controls (IV-D-51 included model parameter information). Two
of the commenters (IV-D-20, IV-D-54) cautioned that this will
burden small landfills and State regulatory agencies. They
claim that proper cutoffs for periodic reporting for emission
rate cutoffs of 150 and 100 Mg/yr of NMOC are 550,000 Mg of
waste and 375,000 Mg of waste, respectively.
One commenter (IV-D-44) stated that due to difficulties
of estimating the lifetime and design capacity of landfills,
kli-85\04 2-148
-------
the cutoffs for reporting for levels of 150 Mg/yr of NMOC
apply only to landfills within an acceptance rate exceeding
35,000 Mg/yr.
Another of the commenters (IV-D-20) suggested that design
volume, and not waste mass as proposed by the EPA, be used in
deciding the reporting cutoff level. The commenter (IV-D-20)
presented data on waste compaction density and advised that
data on design volume is easier to compile and will be less of
a burden on States to regulate.
Response: The design capacity exemption was reevaluated
in the interim between proposal and promulgation, and has been
revised to 2.5 million Mg or 2.5 million m3. This level was
chosen because it significantly reduces the reporting and
recordkeeping burden on the landfills as well as the State and
local agencies, while only about 15 percent of the potential
NMOC emission reductions are lost. Setting a reporting
requirement based on annual acceptance rate does not take into
account that the landfill could have large amounts of refuse
in place emitting more than 50 Mg/yr. Section 2.4.1 of this
chapter, "Design Capacity Exemption," includes further
discussion on this topic.
Comment; One commenter (IV-D-32) stated that S 60.753(b)
of the proposed regulation, which discusses the calculation of
the NMOC emission rate after a gas collection system is
installed, is unclear about whether the calculated NMOC
emission rate should be reported, and if so, how often and to
whom. The commenter also questioned what should be done if
calculated emissions exceed 150 Mg/yr and whether this NMOC
calculation will be the basis for collection system
modifications.
The commenter (IV-D-32) recommended that S 60.756(a)(1)
of the proposed regulation specify the scale of the map which
the regulation requires to be submitted. The commenter also
suggested that S 60.756(d)(1)(iii) of the proposed regulation
include a reference to the correct method and equation to be
klk-85\04 2-149
-------
used in calculating NMOC emissions reports required by the
collection equipment removal report.
Response; Section 60.754(b) of the final NSPS provides
an equation to calculate the NMOC emission rate after a
collection system has been installed. This calculation is
necessary to determine the NMOC emission rate for a
• \
pre-existing system and for system removal. A landfill is
exempt from the requirement to calculate and report an annual
NMOC emission rate [see §S 60.752(b)(2) and 60.757(b)(3)]
while complying with the provisions for collection and
control. The NMOC emission rate must, however, be calculated
in order to meet the conditions for system removal in
S 60.752(b)(2)(v). Since better information for estimating
the NMOC emission rate would be available from the system, the
EPA is requiring the use of procedures including this
information as a condition for system removal. The final
regulation does not specify the scale of the landfill map, but
leaves this decision up to the discretion of the landfill
owner or operator. Different scales may be appropriate to
present different configurations.
Comment; One commenter (IV-D-32) stated that the
regulation does not distinguish between isolated units of a
landfill that may have been closed years ago and units that
are still accepting waste. The commenter pointed out that the
older portions would be used to calculate NMOC emissions and
this would not represent the NMOC emissions of the newer
portions. The commenter recommended that these issues be
resolved and that a registered civil engineer or certified
engineering geologist certify that the site is closed before
it is considered closed.
Response; The equation for estimating NMOC emissions in
S 60.754(a)(1)(i) of the final NSPS accounts for reduced
emissions from older portions of a landfill by utilizing the
actual year-to-year waste acceptance rate. If the
year-to-year waste acceptance rate is not known, the equation
kLk-85\04 2-150
-------
presented in S 60.754(a)(1)(ii) of the final NSPS must be
used.
Comment: One commenter (IV-D-18) requested that the EPA
revise the provisions for compliance reports to include
immediate documentation of equipment malfunctions. In
addition, the commenter argued that semiannual reports should
be made public. Another commenter (IV-F-6) stated that flare
flame outages should be reported if they exceed 1 hour.
Response: Since proposal, the semiannual reports have
been changed to annual reports in order to reduce the
reporting burden. As specified in the final rule, annual
reports must contain the following information:
(1) Value and length of time for exceedance of monitored
parameters.
(2) Description and duration of all periods when the gas
stream is diverted from the control device or has no
flow rate.
(3) Descriprion and duration of all periods when the
control device was not operating for a period
exceeding 1 hour and length of time the control
device was not operating.
(4) All periods when the collection system was not
operating in excess of 5 days.
(5) The location of each exceedance of the 500 parts per
million methane concentration and the concentration
recorded at each location for which an exceedance
was recorded in the previous month.
(6) The date of installation and the location of each
well or other collection device added to the
collection system pursuant to S 60.755.
As stated under (3) above, flare flame outages of less
than one hour are not required to be reported in the annual
report. However, all periods exceeding one hour must be
included in the report. The 1-hour time period assures that
significant emission events are reported, while allowing for
short-term problems that are rapidly corrected. There are
klk-85\04 2-151
-------
unavoidable circumstances that will cause short term problems
in the operation of flares and other control devices. The
1-hour time period is reasonable to allow operators time to
discover the problem and correct it or route emissions to a
back-up control device. The amount of emissions released in a
period shorter than 1 hour would be relatively small.
The public may obtain copies of annual reports by
contacting the government agency or landfill operator
responsible for the reports. The availability of information
•
to the public is discussed in 40 CFR 60.9.
Comment; Two commenters (IV-D-18, IV-D-45) requested
that landfills be required to submit annual reports and not be
allowed to submit the 5-year estimates allowed under the
proposed regulations because of the negative health affects of
NMOC.
Response; The report submitted with the 5-year estimates
is the same report as the annual report except emission
estimates are reported for 5 years instead of one. The only
factor affecting the accuracy of the 5-year report that does
not influence the 1 year report, is the difficulty in
predicting acceptance rates in the future.
Section 60.757(b)(1)(ii) of the final NSPS requires the owner
or operator to submit a revised 5-year report if the
acceptance rate exceeds the estimated waste acceptance rate in
any year reported in the 5-year estimate. The EPA considers
the 5-year report as effective as 5 annual reports in tracking
NMOC emission potential.
2.16 REGULATORY OVERLAP
Comment: One commenter (IV-D-19) voiced concern about
the regulatory overlap due to differing regulatory
requirements between local, State, and Federal agencies. The
commenter suggested creating provisions to increase
coordination among the various agencies to aid in permitting,
and other administrative duties. Another commenter (IV-D-39)
commented on the statement, "the State, county, or
Administrator may request other reasonable information as may
kli-85\0* 2-152
-------
be necessary to verify the maximum design capacity of the
landfill" and "reported NMOC emission rate." The commenter
stated that the inclusion of three separate governmental
bodies in the requirement is unworkable and will place undue
burdens on the landfill owners/operators in responding to
information requests. Also, the commenter was concerned with
the fact that the term "reasonable" is undefined and since no
authority has been granted to a regulatory agency to determine
"reasonableness," it would be possible that allowing this
provision could be used to delay operations at a landfill.
The commenter recommended that "State, county, or
Administrator" be deleted from the requirements and be
replaced with "Administrator." The term "Administrator is
defined in the General Provisions to 40 CFR 60 as the
Administrator of the EPA or his authorized representative. In
most cases, the States have been authorized to implement NSPS.
Response: The EPA shares the commenters concerns over
regulatory overlap and encourages States to increase
coordination among agencies responsible for issuing permits.
In order to reduce ambiguity, the term "reasonable" will not
be included in the final regulation as it is not referred to
in the General Provisions. As requested by the commenter,
references to State, county, or Administrator will be replaced
by the term "Administrator." The term "Administrator" is
defined in the General Provisions to 40 CFR 60 as the
Administrator of the EPA or his authorized representative. In
most cases, the States have been authorized to implement NSPS.
Comment; One commenter (IV-D-2) stated that the standard
was inconsistent with Federal RCRA regulations. The commenter
explained that MSW landfills normally contain an unregulated
amount of RCRA waste as household toxics, and, therefore, the
landfill should be subject to a greater level of control, such
as 99.99 percent instead of 98 percent.
Response; The EPA disagrees with the comment that the
regulations are inconsistent with RCRA and that the presence
of household wastes warrants greater control. This rule is
klk-85\04 2-153
-------
based on BDT. As explained in the proposal preamble and in
section 2.6.3, the best demonstrated level of control is
98 percent. There are no demonstrated technologies that are
applicable for all landfills that achieve 99 percent or
greater reduction at a reasonable cost. Household toxics may
be included in household waste, but air emissions resulting
• %
from them are not subject to greater control under RCRA than
under these regulations. A landfill subject to these
regulations is not exempt from any of its RCRA
•
responsibilities. Air emissions from the landfill may also be
subject to the BDT of the air criteria under 40 CFR 258.24 of
subpart c.
2.16.1 Superfund Interface
Comment; One industry commenter (IV-D-27) supports the
designation of BDT under these regulations as "applicable or
relevant and appropriate requirements" for Superfund sites,
noting that properly designed passive systems should also be
permitted for Superfund sites without synthetic liners, due to
the short-term nature of many of these projects.
One commenter (IV-D-48) stated that Superfund sites
already address most of the factors (ozone production,
carcinogenic risk, threat of fire and explosion) listed in the
proposed standards in support of gas collection and control
systems. The commenter explained that the majority of
Superfund landfills contain only about 10 percent industrial
wastes, yet the financial burdens of control will be absorbed
by industry as the regulation is currently written.
Response; A Superfund site that is also a former MSW
landfill that would otherwise be covered by these regulations
presents identical concerns to those presented by a
non-Superfund MSW landfill. The applicability of these
regulations is based on NMOC emission rate. If the Superfund
landfill emits NMOC above the emission rate level,
installation of a collection system is appropriate and
relevant, as well as applicable. The collection system must
meet the minimum design requirements in the EG which are
kl)c-85\04 2-154
-------
essentially equivalent to those of the NSPS. Generally,
passive systems with add-on control for the collected gases
may not be as practical or economical as active systems, but
the regulations allow the use of them as long as they have
liners and equivalency is demonstrated as discussed in
S 60.752(b)(2) of the final NSPS.
2.16.2 Prevention of Significant Deterioration Interface
Comment; One commenter (IV-D-23) requested clarification
of whether the BDT in the proposed regulations will satisfy
the BACT requirements under the PSD program and when further
control measures should be implemented as part of BACT
decisions.
Response: The BACT decision under the PSD program is
made on a site-specific basis when the landfill is permitted
in order to address a broader range of site-specific concerns
than under section ill. The BDT establishes a minimum control
level for new landfills, and BACT decisions cannot be less
stringent than BDT. The BDT may serve as BACT in many cases.
However, a PSD review is still required for individual new or
modified landfills that meet PSD applicability criteria, and
BACT will be determined during the review based on the
considerations required under the PSD program. The PSD
program is separate from the NSPS; the NSPS regulation will
not address BACT determinations.
Comment: One commenter (IV-D-17) suggested that
estimating ambient air contaminant levels using a screening
method (they mentioned Air Guide 1, NYSDEC) would help
determine the effects of NMOC on sensitive receptors within
the surrounding landfill area. The commenter requested that
air review parameters (i.e., location of sensitive parameters,
site wind rose, etc.) should be included under S 60.756 in the
proposed regulation.
Response: These regulations are being developed and
promulgated under section 111, which requires the application
of BDT, not modeling of ambient concentrations at "sensitive
receptors," as required under the PSD program.
kli-85\04 2-155
-------
Comment: One commenter (IV-D-54) stated that no changes
would need to be made to the PSD provisions in 40 CFR 51.166
and 40 CFR 52.21 if LFG is regulated as VOC. The commenter
explained that regulating MSW landfills under PSD would not be
useful since new landfills are now covered under the NSPS
which requires that BDT be used for the control of LFG. The
• %
commenter stated that since PSD increments or NAAQS have never
been proposed for MSW emissions or NMOC, ambient air quality
impact analysis for LFG or VOC would have no significance.
The commenter noted that they have not come across any unit
risk factor data for LFG. The commenter also stated that LFG
is generated as fugitive emissions and it is unlikely that a
new or modified landfill would need to undergo
pre-construction review since fugitive emissions would not be
counted for applicability purposes under the existing federal
PSD provisions.
Two commenters (IV-D-26, IV-D-39) recommended that PSD
review be based on existing PSD criteria and not on the new
"de minimis" level for NMOC. The commenters stated that there
is no need to impose stricter PSD review standards on
landfills for NMOC than those currently applicable to other
industries and other sources which emit the similar compound,
VOC, at equivalent or greater rates.
Response; The EPA is designating MSW landfill emissions
as a designated pollutant under sections lll(b) and (d) on the
basis of both health and welfare impacts. The MSW landfill
emissions consist of a composite of pollutants including
methane and NMOC. The constituent pollutants that make up the
MSW landfill emissions can vary significantly both within a
landfill and from landfill to landfill. Thus, to reduce the
burden of measuring all components of MSW landfill emissions,
the EPA is designating NMOC as a measurement surrogate for MSW
landfill emissions. The NMOC are designated because NMOC
include VOC as the commenter has recommended, as well as
photochemically nonreactive compounds, including both toxic
kUc-85\04 2-156
-------
and nontoxic compounds, that are of concern under this
rulemaking.
A consequence of this action is that the PSD regulations
would now apply to all MSW landfills defined as major sources
which would have "significant" increases in this pollutant
(MSW landfill emissions measured as NMOC). Absent any
significance levels in the PSD regulations to exempt
de minirois situations, PSD review would be triggered by any
increase .in MSW landfill emissions. Thus, to maintain a
manageable review process, MSW landfill emissions need to be
added to the part 51 and 52 list of PSD pollutants and a
significance level established. The EPA proposed to establish
40 tons/yr (measured as NMOC) as the significance level for
MSW landfill emissions. However, in consideration of public
comments, the final rule establishes a significance level of
45 Mg/yr (50 tons/yr) of NMOC. Given the typical composition
of landfill gas, a 50 tons/yr NMOC level is comparable to the
previously established PSD significance level of 40 tons/yr of
VOC. Under NSR regulations, a PSD review would be required
for increases in MSW landfill emissions at major sources at or
above this significance level.
While it is true that the PSD regulations state that
fugitive emissions are not counted toward the potential to
emit of a source category which is not specifically listed,
the PSD regulations define fugitive emissions as those
emissions which could not reasonably pass through a stack,
chimney, vent, or other functionally equivalent opening." It
is feasible for a landfill to install a gas collection system,
as is required for some sources under these regulations.
Therefore, MSW landfill emissions, which can be collected, are
not fugitive emissions for PSD purposes. Thus, the
commenters' assertion that the emissions would not be counted
to determine applicability is not valid. These regulations
also establish methods by which NMOC emissions from MSW
landfills can be calculated and compared to the lists in parts
51 and 52, for PSD applicability purposes.
kli-85\0* 2-157
-------
Comment; One commenter (IV-L-1) suggested that 40 tons
per year of NMOC emissions be added to the definition of
significance for nonattainment NSR at 40 CFR 51.165(a)(1)(x)
in addition to those changes proposed to the PSD regulations
at 40 CFR 51.166 and 52.21.
Response; Under the final rule, 40 CFR 51.166 and 52.21
• %
have been amended to include 50 tons per year of NMOC.
Nonattainment new source review at 40 CFR 51.165 covers only
those pollutants for which NAAQS have been established. Since
NAAQS for NMOC have not been established, NMOC cannot be added
to the definition of significance for nonattainment new source
review. However, because VOC are a significant portion of
NMOC and a significance level for VOC (related to the ozone
NAAQS) is included in 40 CFR 51.165(a)(1)(x), landfills are
sources that must be considered for nonattainment NSR.
Comment; Two commenters (IV-D-26, IV-D-39) said that
clear guidelines for PSD review should be established so that
timely, objective decisions can be made as to whether either
PSD permits will be required or determinations of
nonsignificant impact will be granted to the landfill.
Further, the commenter suggested that the EPA should decide
whether there is a need for PSD review of new or modified
landfills since open and/or enclosed flares are BACT, and no
other practical methods of reducing methane and NMOC emissions
exist. One of the commenters (IV-D-39) asserted that under
the NSPS, proper landfill capping, reducing leachate, and
other landfill operational factors have no bearing on the
calculation of the NMOC emission rate.
Response; The New Source Review Workshop Manual provides
guidance on the process by which new sources and major
modifications are evaluated for applicability to the PSD
regulations. This manual was published in draft form in
October of 1990. In addition, for MSW landfills, the
definition of a major source (in 40 CFR parts 51 and 52)
establishes the size at which emissions from a landfill are
considered in determining whether or not the landfill is
klk-85\0* 2-158
-------
major. Further, the definition of "significant" in those
regulations will include the threshold level at which an
emissions increase is significant.
The CAA, in section 165(a), reguires that all major
stationary sources and major modifications proposed for
attainment areas be subject to PSD review. A PSD permit
•»
review is a case-by-case evaluation of a proposed major new
source or major modification. A BACT determination is one of
the reguirements of a PSD permit review [see
section 1*65 (a) (4)], and BDT may or may not equate with BACT.
The EPA is currently selecting properly designed gas
collection and combustion devices achieving 98 percent NMOC
emission reduction as BDT for landfills emitting greater than
50 Mg/yr of NMOC under these rules. However, States may
decide to consider other, or more stringent, control systems
as BACT, or reguire controls on landfills emitting less than
50 Mg/yr of NMOC. Thus, PSD review would still be needed for
new or modified landfills.
Comment; Two commenters (IV-D-18, IV-D-45) wanted the
standards to include provisions stating that MSW air emissions
from landfills on National Park or Forest lands will not be
allowed to negatively affect the air quality of these National
Park or Forest lands. In addition, one of the commenters
(IV-D-18) suggested that lowest achievable emission reduction
(LAER) be used in place of BDT if any forms of waste are
accepted from outside of the National Park or Forest or if any
Federal park or forest land is exchanged for the purpose of
creating a landfill.
Response; The PSD program provides for the protection of
air quality in those National Parks and National Forests
designated as Class I areas. Major new sources and major
modifications in PSD areas are required to apply BACT and to
model air quality impacts, including whether the proposed
source would cause or contribute to exceedances of NAAQS or
increments. There are no -NAAQS or increments for "MSW
landfill emissions," but other provisions of the PSD
klk-85\04 2-159
-------
regulation specifically designed to protect Class I areas
still apply. Concerned Federal land managers may, for
example, use the air quality impact analyses to determine
whether there will be an adverse impact on AQRVs. If the
reviewing agency agrees with a Federal land manager's adverse
impact determination, the agency must deny the permit.
For National Parks and other federal lands not classified
as Class I, the PSD program still offers protection from MSW
landfill emissions through the additional impacts analysis,
which is an assessment each PSD permit applicant must make of
the impact the proposed source or modification will have on
soil, vegetation, and visibility. The Federal land manager
can argue that there will be unacceptable impacts based on
these studies.
Finally, there is no regulatory authority for requiring
LAER for MSW landfill emissions because LAER applies only to
major sources of a nonattainment area pollutant, and there are
no attainment areas for MSW landfill emissions. New or
modified landfills may, however, be subject to nonattainment
area major source review (or to PSD review) if the VOC
emissions from the landfill exceed the threshold levels for
major status. In attainment areas, the threshold for major
sources is 250 tons/yr. (For certain listed categories, the
threshold is 100 tons/yr, but landfills are not one of the
categories listed in the PSD rules, so the 250 tons/yr
threshold applies.) Fugitive emissions are not included in
determining whether the 250 tons/yr threshold is exceeded, but
collectable emissions must be included. Because this NSPS and
EG have found collection systems to be feasible, most landfill
emissions are considered collectable for PSD purposes. The
EPA estimates that approximately 70 percent of NMOC emitted by
MSW landfills is VOC as presented in the memorandum
"Estimating the percentage of non-VOC constituents in
\
Municipal Solid Waste Landfill Nonmethane Organic Compound
Emissions" (Docket No. A-88-09, Item No. II-B-39). If the VOC
emission rate exceeds 250 tons/yr in attainment areas or the
klk-85\04 2-160
-------
major source threshold in nonattainment areas (from 100 down
to 10 tons/yr, depending on the severity of the nonattainment
area), then the landfill constitutes a major source and is
subject to the PSD or nonattainment area provisions regardless
of its NMOC rate.
2.16.3 Subtitle D Interface
" %
Comment; Two commenters (IV-D-7, IV-D-26 and IV-F-6)
expressed concern for the cost, handling, and treatment of gas
condensate, sometimes classified as a hazardous material,
resulting from gas collection and energy recovery systems.
One commenter (IV-D-7) requested that the EPA keep in mind the
outcome of having all future subtitle D landfills regulated
partly as subtitle C (hazardous waste) landfills because the
required gas collection system will produce gas condensate.
Another commenter (IV-D-26) suggested that gas condensates be
either specifically excluded from or specifically included
under subtitle C.
Response; The liquid from gas condensate is only a
hazardous waste if it is tested and determined to be a
characteristic hazardous waste. A subtitle D landfill which
generates a hazardous waste would not become a subtitle C
landfill. However, the hazardous condensate would have to be
handled at an appropriate TSDF.
Comment; One commenter (IV-D-15) wanted the EPA to
discourage landfill siting in areas that already exhibit heavy
pollution or that would add to deforestation. The commenter
further said that the siting of a landfill requiring the
removal of trees should be given an emissions rating prior to
receiving any waste because it has already degraded air
quality by removing trees, whereas the siting of a landfill on
land already void of trees could be given a zero emissions
rating.
Response; These regulations apply to air emissions from
landfills. The siting of landfills is covered by RCRA
subpart D, part 258, finalized on October 9, 1991
(56 FR 50978).
klk-85\04 2-161
-------
2.17 STATE PROGRAM SUBMITTALS
Comment; One commenter (IV-D-17) indicated that the
requirement to submit a State program for implementing the EG
to the EPA by the ninth month after promulgation was not
reasonable because of the lack of revenues and resources
needed to develop and implement a regulatory program such as
this in such a short time period.
Response; The 9-month interval is mandated by
section lll(d) of the CAA, and has been previously
•
incorporated into the NSPS/EG program in 40 CFR 60.23.
Comment; One industry commenter (IV-D-27) recommended
that the EPA develop a standard form for Tier 1 calculations.
Two commenters (IV-D-27 and IV-F-5, IV-F-4) requested that the
EPA provide guidance and oversight to the States in
implementing the proposed regulations, especially in the areas
of the Tiers and system design. The commenters were concerned
that alternative designs would be difficult to get approved by
review personnel.
One commenter (IV-D-51) requested clarification of the
regulated pollutant for the collection of fees under the air
permit program required by the CAA. In particular, the
commenter requested specification of whether only NMOC, or all
landfill emissions, are required to pay the air emissions fee.
Response; The EPA has developed a computer program,
available on disk, to perform the Tier Calculations. The
computer program called the Landfill Air Emissions Estimation
Model (or LAEEM), can be obtained from NTIS, (703) 487-4650.
Government Agencies can also acquire the program from the CTC,
(919) 541-0800 within BSD of OAQPS. The program can also be
down-loaded from the OAQPS CTC bulletin board system, (919)
541-5742. The bulletin board system operator can be reached
at (919) 541-5384. The computer program was revised and will
be available when the regulations are promulgated.
The EPA will publish guidance materials to assist in the
implementation of and compliance with these NSPS and EG. An
enabling document focusing on assisting the agencies who will
kli-85\04 2-162
-------
be responsible for implementing the regulations will be
available soon after the regulations become final. These
materials would also be useful to landfill owners and
operators. Additional enabling materials may also be
available in the future to provide guidance to landfill owners
and operators complying with the NSPS and EG. The enabling
documents may include forms for completing the calculations
for Tiers 1, 2, and 3 to assist the landfill owner/operator
and the implementing agency.
Alternative collection and control system design plans
are allowed under § 60.752 and require a demonstration to the
Administrator's satisfaction of the equivalency of the
alternative provisions to the criteria in S 60.759. The rule
has been changed since proposal to remove the prescriptive
design specifications in S 60.759 and to require site-specific
design plans for active collection systems that meet the
criteria in S 63.759 as well as those that do not. Thus, any
design will require approval, and unique designs will not be
discouraged.
The recently promulgated Title V program includes
provisions for the collection of fees from all sources of CAA
pollutants. This fee assessment was mandated by the CAA
amendments of 1990 in order to provide relief to States in
complying with CAA-mandated activities.
2.18 POLICY ISSUES
2.18.1 Consideration of Methane
Comment: Four commenters requested that methane
emissions be considered to some degree in the development of
the NSPS and EG. One commenter (IV-D-24) contended that
methane reductions should have been considered directly in the
selection of BDT because of methane's global climate change
impacts, which the commenter considered a public welfare
effect warranting attention under section 111 of the CAA. The
commenter recommended using monetary values for CO2 and
methane established by several utility regulatory bodies in
the selection process, noting that not to do so would be to
kik-85\04 2-163
-------
arbitrarily assign methane's harmful effects a value of zero.
The commenter reported that Massachusetts has assigned methane
a value of $220/ton for similar kinds of analyses.
The commenter presented a brief history of the growing
expertise on global climate change and the current view of the
potential for climate change. Additionally, the commenter
presented a range of strategies from various national and
international bodies to address the issue. The commenter
included a quote from the Bush Administration's National
*
Energy Strategy which listed the proposed regulations as
recent U.S. activities aimed at reducing greenhouse gas
emissions. The commenter concluded that clear scientific
consensus exists about the severity of the impact of
greenhouse gases and global climate change. The commenter
disagreed with the EPA's decision that the uncertainty as to
the rate and magnitude of possible climate change was a reason
not to regulate methane. The commenter argued that the EPA
had inappropriately not considered recent NOAA experiments
indicating that the role of methane in global climate change
has been understated by approximately 25 percent. The
commenter cited a paper which proposed that "MSW landfill
methane reduction is one of the potentially most economical
ways to...reduce greenhouse gas problems..."
Another commenter (IV-F-6) recommended that the control
of landfill emissions should be based on methane, which would
allow for establishing tax credits for recovery equipment,
force utilities to pay a reasonable price for alternative
energy, and allow for a methane recovery tradeable credit
system to be developed.
One industry commenter (IV-D-27) supported the Agency's
decision not to consider methane reduction directly in the
selection of BDT, noting, however, that the methane reductions
occurring indirectly from the proposal are significant. The
commenter said that the EPA is currently investigating methane
reduction, and will be in a better position to determine if
kli-85\04 2-164
-------
additional control of MSW landfills is warranted after these
investigations are completed.
Another commenter (IV-D-29) wanted only the ancillary
benefits of methane to be considered since NMOC are the real
focus of the proposed regulation.
Two commenters (IV-D-26, IV-D-33) wanted a .separate
methane standard to be developed to more completely address
the health and environmental effects of methane. One of these
commenter.s (IV-D-26) stated that a methane standard would help
to control both the individual and aggregate effects of
methane from landfills and help to address concerns such as
global warming. Another commenter (IV-D-33) argued that NMOC
are not an adequate surrogate for methane emissions and that
methane merits its own standard according to section ill of
the CAA, which states that standards be established for
sources which may endanger public health or welfare. The
commenter cited several reasons methane poses a danger to
humans and to the environment, including methane's role in
global warming, ability to form ozone in the troposphere,
ability to explode and emit odors, ability to transport toxic
NMOC to the air and landfill surface, and negative effects on
soil and vegetation. The commenter suggested using the same
tier system approach for determining when controls need to be
applied that is used for NMOC under the proposed regulation.
The commenter advised the EPA to disregard the scientific
uncertainties associated with the effects of methane on global
warming and to formulate a separate methane standard to the
final regulation.
Response; In setting standards and EG which reflect BDT
under section 111 of the CAA, the EPA considered reductions of
NMOC directly and methane reductions as an ancillary benefit.
The NMOC was selected as a surrogate for MSW landfill
emissions because NMOC contains the landfill air pollutants
posing more concern, due to their adverse health and welfare
effects. In addition, reducing NMOC concentrations in LFG
will significantly reduce the amounts of methane contained in
klk-B5\04 2-165
-------
LFG. It is estimated that the NSPS will reduce methane
emissions by 3.9 million Mg on a NPV basis and the EG will
reduce methane emissions by 47 million Mg on a NPV basis. The
U.S. Climate Change Action Plan, released in October 1993,
contains a series of actions to reduce emissions of methane
from landfills and other sources. The Climate Change Action
Plan forms the cornerstone of the U.S. National Action Plan
required by the Framework Convention on Climate Change, which
the U.S. signed in 1992. The EPA actions to reduce emissions
of methane and other greenhouse gases will be guided by the
directives contained in the Action Plan. Therefore, the EPA
maintains that no separate BDT for methane is needed at this
time.
Methane reductions have been quantified and considered as
an ancillary benefit of NMOC reductions within these
regulations. Furthermore, the nationwide impacts analysis was
revised for the final regulations to incorporate the economic
effects of the use of combustion devices that achieve energy
recovery to comply with the standards. Since the feasibility
of energy recovery is dependent on methane, incorporating
energy recovery into the national impacts analysis does
increase the influence of methane on the selection of the
final NSPS and EG. The use of energy recovery did not change
the final decision, however, because on a national basis it
was not more cost effective than flares. See section 2.18.2
for a discussion of this decision. The details of the revised
analysis are presented under section 1.3.2, "Revisions to the
Modeling Methodology" in chapter 1 of this document. The EPA
has developed a Landfill Methane Outreach Program to lower
barriers to landfill gas energy recovery and to encourage more
widespread utilization of landfill gas as an energy source.
Information regarding the program can be obtained by calling
the Landfill Outreach Program Hotline at (202) 233-9042.
Comment; One commenter (IV-D-17) felt the regulation
should focus on reducing methane emissions from larger
landfills while encouraging reuse, recycling, and composting
kli-85\0* 2-166
-------
in order to reduce methane emissions from smaller MSW
landfills.
Response; These regulations focus on large emitters, and
although these are often larger landfills, some smaller MSW
landfills may warrant control based on NMOC emission rates.
These regulations, although based on NMOC emissions, will
achieve significant reductions in methane emissions. The EPA
is encouraging the use of source reduction methods such as
reuse, recycling and composting through various programs, and
such programs are being adopted at the State level as part of
an overall waste reduction strategy. Because of the
variability of economic impacts resulting from source
reduction activities, the EPA considers the state and local
level the appropriate place to make decisions on recycling and
composting at this time. See the report, "The Solid Waste
Dilemma: An Agenda for Action," (EPA/530-SW-89-019;
February 1988) for a more thorough discussion of the EPA's
overall solid waste policy. As discussed in the preamble to
the final RCRA regulation (56 FR 50978; October 9, 1991), the
EPA has begun a number of initiatives to expand recycling
efforts, including: market studies, federal recycling
procurement guidelines, the development of training materials
for State and local recycling coordinators, publications
(i.e., composting), and the establishment of a National
Recycling Institute. The institute is comprised of business
and industry representatives and will address recycling
issues.
2.18.2 Consideration of Energy Recoveryl3
Comment: One commenter (IV-L-3) contended that the cost
analysis did not consider that many areas of the country have
strict air regulations which would require air emission
control equipment to be installed on an energy recovery
system, rendering an energy recovery project uneconomical.
Response: The cost analysis estimated the cost of
installing flares at all landfills above the design capacity
and emission rate cutoff, as well as the cost of energy
klk-85\04 2-167
-------
recovery devices. There are many factors that play a role in
the use of energy recovery that were not considered in the
nationwide impacts analysis because of limited resources and
because the impact of many of these factors cannot be
accurately quantified. The selection of energy recovery is a
site-specific economic decision, and therefore, the EPA will
•«
not mandate energy recovery within these standards. An owner
or operator will have to consider whether applicable rules
will render an energy recovery project uneconomical for their
•
particular landfill.
Comment; One commenter (IV-D-24) asserted that the EPA
should attribute some value to energy recovery in the
selection of the emission rate cutoff. The commenter argued
that not to give energy recovery a value is to arbitrarily
assume it will have no cost impact. The commenter further
recommended that some specific provisions addressing energy
recovery (e.g., requirements to perform feasibility studies if
control is required) be included in the final regulations.
Two commenters (IV-D-21, IV-D-33) suggested that energy
recovery technologies also be defined as BDT, and at the very
least that additional language be added to the regulation and
guideline to strongly endorse and encourage energy recovery.
One commenter (IV-D-21) further suggested that the cost
analysis be revised to incorporate the role of energy
recovery.
Several commenters wanted energy recovery to be promoted
through this NSPS in some form. Three commenters (IV-D-18,
IV-D-20, IV-D-50) supported some form of the "Energy Recovery
Option 2" discussed in the proposal preamble. Two of these
commenters (IV-D-20, IV-D-50) suggested elimination of the
public meeting provisions requirement. One of these
commenters (IV-D-20) claimed Option 1 fails to explore energy
recovery or to encourage pollution prevention at MSW
landfills. The commenter supported a modified Option 2 which
would require landfill operators to examine pollution
prevention cost-effectiveness in hopes of compelling all MSW
kli-85\04 2-168
-------
landfills to consider energy recovery systems. The commenter
recommended including an energy recovery analysis with the
permit application as an alternative. The commenter stated
that publicly-owned landfills may overlook the benefits of
energy recovery in order to save money now instead of
investing in the future.
The second commenter (IV-D-50) also supported Option 2,
provided that the public hearing was eliminated, but cautioned
that any specific energy recovery requirement could result in
•
a relatively inefficient, higher cost energy conversion
technology replacing a more efficient, lower cost energy
technology (i.e., natural gas-fired generation).
Another commenter (IV-D-33) suggested that a combination
of energy recovery Options II and III be adopted. The
commenter recommended that landfill operators perform energy
recovery potential analyses as required in Option III and that
they be required to install an energy recovery system if the
analysis produces at least the potential for the owner to
break even. The commenter suggested that if the analysis is
found to be conflicting, the analysis should be discussed at a
public meeting to see whether installation of an energy
recovery system should be required. The commenter asserted
that energy recovery would offset control costs, decrease
fossil fuel use, and reduce global warming and acid rain
effects. The commenter noted that many landfills already have
gas collection infrastructures in place to aid in energy
recovery and they urged the EPA to consider these factors in
the cost evaluation of energy recovery.
One commenter (IV-D-26) expressed support for the EPA's
selection of Energy Recovery Option I. The commenter agreed
with the EPA that energy recovery can be a financial risk due
to the variability of markets for gas use, the difficulty of
predicting reliable gas production rates, and discrimination
against the use of LFG by utilities. The commenter urged the
EPA to pursue energy recovery by reviewing State and Federal
klt-85\04 2-169
-------
tax laws and regulations, and by expanding methane recovery
"credit systems."
One industry commenter (IV-D-27) supported the Agency's
decision to leave the evaluation of energy recovery up to the
owners and operators of each site, and not to consider the
cost impacts of energy recovery in selecting the level of the
standard.
One commenter (IV-D-50) asserted that important topics
such as system availability and reliability and backup flare
*
systems for use during outages had been excluded from the
proposal BID discussion of energy recovery. The commenter
disagreed with the EPA's turbine operation estimate and noted
that LFG is very highly corrosive with a high potential to
contaminate lubricants. The commenter did, however, support
the requirement of the analysis, noting that if energy
recovery is economic, it should proceed under local laws and
regulations.
Other commenters suggested energy recovery should be
encouraged through tax incentives (IV-D-11), ease of
permitting (IV-D-19), requiring utilities to purchase
recovered energy at retail prices (IV-D-11, IV-D-36) or
compliance extensions for MSW landfills with energy recovery
systems in place (IV-D-43). One of these commenters (IV-D-43)
said the proposed regulation (which requires a gas collection
system that reduces NMOC by 98 percent) acts to discourage gas
mining as an energy recovery option. The commenter suggested
that the regulation be amended to include a more flexible
guideline for those landfills with gas recovery systems. The
commenter also suggested that landfills that employ gas
control systems which recover the gas for use should be given
a less stringent air emissions reduction standard.
In response to the EPA's request for comments regarding
incorporating climate change considerations in the cost
analysis and proposals, one commenter (IV-D-21) recommended
that the EPA include methane and CO2 emissions reductions
obtained through energy recovery under the regulation and
kLk-85\04 2-170
-------
guideline. Another commenter (IV-D-19) indicated that some
form of incentive for energy recovery in the regulations would
be advantageous. Still another commenter (IV-D-17) supported
the evaluation of methane collection for energy recovery.
Another commenter (IV-D-29), stated that the EPA was
correct in leaving the decision to pursue energy recovery to
• %
the owner or operator and not to include energy recovery in
the BDT decision because of the difficulty in knowing how much
LFG will be generated and whether a market for it will be
•
available.
One commenter (IV-D-17) indicated that EPA-funded
contracts should be awarded to research methods for removing
CO2 from MSW landfills to have purer methane gas. Another
commenter (IV-D-19) suggested resource recovery facilities as
another viable form of energy recovery.
One commenter (IV-D-21) was concerned about the quality
of gas leaving the landfill site for sale. The commenter
stated that untreated LFG in a pipeline could pose a human
health risk and that pipeline systems would be subject to
rigorous permitting and operational requirements. The
commenter also stated that not all LFG will have the necessary
properties for efficient combustion. Because of these
concerns, the commenter recommended that the EPA provide
guidelines on the gas quality necessary for LFG to be
transported in pipeline systems. At the very least, the
commenter requested that the EPA require landfill owners and
operators to be subject to RCRA since they are hazardous waste
generators. The commenter asserted that this would safeguard
natural gas companies and end-users.
Response: The EPA continues to consider that the use of
energy recovery should be a site-specific decision. Such a
decision should be made after the landfill owner or operator
considers the potential savings given the uncertainty and risk
for that particular landfill. Many variables come into play
when considering energy recovery, such as gas market
fluctuations, gas production rates, and the quality of the
kli-85\0* 2-171
-------
gas. For this reason, the EPA will not mandate energy
recovery within these standards. The use of resource recovery
facilities is a solid waste issue, and the focus of this
regulation is on air emissions from landfills.
The EPA is not requiring an energy recovery feasibility
analysis because the EPA does not consider such an analysis
• %
appropriate as part of an NSPS. The EPA still considers the
selection of energy recovery to be a site-specific economic
decision, rather than a pollution control decision within the
•
purview of section ill of the CAA. The EPA can, however,
promote energy recovery by discussing it in the preamble and
showing its benefits by including the use of energy recovery
in the nationwide impacts analysis. The potential for cost
savings via energy recovery for those landfills subject to
this regulation is discussed in section 1.3 of chapter 1 of
this document, and outreach efforts are described in
section 1.2.1.4 of chapter 1.
The EPA decided to incorporate energy recovery in the
nationwide impacts analysis by adding an energy recovery
analysis to the original flare analysis upon which the
selection of BDT is based. For this second analysis, the
nationwide impacts analysis was modified to select the
least-cost of three control options for each model landfill:
flares, I.e. engines, or turbines.
It was determined that using energy recovery systems is
generally more cost effective at larger landfills; however, on
a nationwide basis energy recovery did not prove to be
significantly more cost effective than flares. The reason for
this is that it was estimated that most landfills using energy
recovery systems will do so in the absence of the regulation,
and such landfills were not included in the nationwide impacts
analysis. The revised nationwide impacts are detailed in the
memorandum "Revised Nationwide Impacts for Development of
Regulatory Alternatives," June 4, 1993, (Docket No. A-88-09,
Item No. IV-M-7).
klk-85\04 2-172
-------
Comment; One commenter (IV-D-11) provided data on fuel
cell operation and stated that the regulation should promote
energy recovery by requiring that the methane captured with
NMOC be used for electricity by using fuel cells (not
combustion). Because fuel cells emit only low levels of air
pollutants, the commenter suggested that the fuel cell be
listed as BACT. The commenter maintained that the proposed
standard should require energy recovery equipment to meet air
emissions standards comparable to those of SCAQMD
Regulation 1110.2 and SCAQMD proposed regulation 1135. The
commenter also suggested that the regulations should require
that methane be converted to electric power on government
lands.
One commenter (IV-G-2) supported all comments submitted
by Commenter IV-D-11. The commenter agreed that the EPA's
regulations should require that methane collected in
conjunction with the collection of NMOC not be combusted, but
be used for electric power production. The commenter
supported listing the fuel cell as BACT noting that this would
allow energy recovery at MSW landfills in the most efficient
and environmentally safe manner.
Response: The use of fuel cells is currently being
investigated by the AEERL of the EPA. While this technology
looks promising, the EPA's investigation will not be completed
in time to evaluate whether fuel cells could be listed as BDT
within these regulations. As more information becomes
available, however, an owner or operator could submit a
collection and control plan incorporating the use of fuel
cells. The EPA considers the selection of energy recovery to
be a site-specific economic decision and will not mandate
energy recovery within these standards. The EPA encourages
the use of energy recovery methods, including fuel cells,
where it is feasible and cost-effective.
Comment; One commenter (IV-L-2) recommended that energy
recovery be required under the NSPS and that the offsetting of
klk-85\04 2-173
-------
utility emissions by the generated energy be included in the
economic analysis of the NSPS.
The commenter (IV-L-2) included a figure showing that
greenhouse gas emissions are higher at a facility using energy
recovery compared to a waste-to-energy facility and are higher
when no energy recovery is used. The commenter (IV-L-2) also
said the figure disregards the offsetting of emissions from
utilities or other sources that would be reduced because of
energy recovery at landfills which can amount to a significant
abatement of utility emissions. The commenter also referred
to Titles I and IV as subjects of Congressional attention
regarding significant abatement of utility emissions.
Response; The EPA continues to consider the use of
energy recovery a site-specific decision, and will not mandate
it within these standards. For further information on
comments received on this subject in response to the proposed
rule and the EPA's response, see the memorandum "Analysis on
Landfill Gas utilization for the Soon-to-be Promulgated Clean
Air Act Regulations for Municipal Solid Waste Landfills,11
September 14, 1993 (Docket No. A-88-09, Item No. IV-B-5).
Comment; One commenter (IV-L-7) disagreed with the
regulation's failure to credit the value of avoided
environmental externalities (reducing global warming, local
air pollution problems, and dependance on foreign suppliers of
fuel) associated with energy recovery in the comparison
between energy recovery and flaring. The commenter (IV-D-7)
compared energy recovery and flaring, stating that energy
recovery avoids the need to use costly fossil fuel to produce
energy and does so without adding additional pollution to the
atmosphere. The commenter (IV-D-7) contended that these
benefits can not be ignored and an emission standard should be
judged by how well it prevents total pollution, not solely by
how cost effective it is to install a technology relative to
less effective alternatives. The commenter (IV-D-7) stated
that the EPA should require energy recovery so long as it is
cost effective when compared to avoided energy and capacity
klk-85\0* 2-174
-------
costs of the electric system along with the associated
environmental costs.
Response; There are many factors that play a role in the
use of energy recovery that were not considered in the
nationwide impacts analysis; some are site specific while
others, those mentioned by the commenter, are national
factors. A more rigorous review of these factors was not
performed because of limited resources and because the impact
of many of these factors cannot be accurately quantified.
However, the reduction in fuel usage at electric utilities was
reflected to varying degrees in the buy-back rates used in the
energy recovery modeling. Also, the purpose of the least cost
option in the nationwide impacts analysis was to estimate the
number of landfills that would potentially choose energy
recovery because of economics and then estimate nationwide
impacts based on the control devices predicted to be applied.
Requiring energy recovery as the control device is not
appropriate because it is a site-specific decision. There is
an element of risk that owners or operators take to use energy
recovery and it is not successful in all cases. Although
there are national benefits that may occur when a facility
uses energy recovery, it is not in the best interest of
landfill owners or operators, or the nation to require
facilities to use energy recovery and face the economic risk
of a nonproductive landfill. These decisions are better made
on a site-specific basis. The NSPS emission limits in the
standard are based on use of BOT as required by section 111 of
the CAA. The owner or operator should have the flexibility to
use any control technique that can meet the specified control
levels. Section 1.3 of this document estimates some of the
national benefits of using energy recovery, such as reducing
the fuel used by utilities.
Cgiflflient• One commenter (IV-L-3) maintained that the cost
of a flaring system should have been included in the energy
recovery system cost. The commenter . (IV-L-3) stated that an
energy system does not operate for the full gas generation
klk-85\04 2-175
-------
life span and flares are needed at the beginning and at the
end of landfill operation when gas generation is lower. The
commenter (IV-L-3) stated that flares are needed as excess
flow control systems. The commenter (IV-L-3) also stated that
flares are also needed at least 20 percent of the total
control time when gas production levels decrease and energy
• \
recovery systems are inefficient at partial loads.
Response: The EPA agrees that energy recovery will most
likely not be used throughout a landfill's gas generation
•
life; however, this assumption was made in order to simplify
the analysis for the least cost option. Therefore, the cost
estimated for a landfill using energy recovery is
overestimated since it was assumed that energy recovery
equipment (I.e. engine or turbine) would be used from the
beginning to the end of the control period at the landfill.
In reality, as the commenter pointed out, a less costly flare
would most likely be used at the beginning and the end of the
control period. The effect of this cost overestimate is that
fewer landfills are estimated to use energy recovery than the
actual number of landfills that could benefit from using
energy recovery if the control system was switched during the
control period of the landfill.
The flare system used at the beginning and the end of the
control period would also be used as a backup in times of low
gas flow and partial loads to the energy recovery system, and
in times when there is excess flow. The overestimated cost
due to assuming that the landfill would use energy recovery
for the full control period is assumed similar to the cost of
a back-up flare system throughout the control period with
energy recovery control devices.
Comment; One commenter (IV-L-3) supported the EPA's
attempt to eliminate the bias of landfills that would develop
gas to energy systems in the absence of the rule. However,
the commenter (IV-L-3) maintained that the data base still
contained anomalies other than those specifically identified
by the EPA. The commenter (IV-L-3) further stated that it is
klk-85\04 2-176
-------
impossible to eliminate all biases and that future gas to
energy projects may be influenced by factors similar to those
the EPA is attempting to remove. For these reasons, the
commenter (IV-L-3) recommended that the data base not be
modified and that it include all projects. The commenter
(IV-L-3) stated that the increase of the energy buyback rate
in New Jersey, New York, and Pennsylvania brings in a
potential bias.
The commenter (IV-L-3) stated that the EPA has deleted
California gas-to-energy projects in the data base to reduce
bias. The commenter (IV-L-3) stated that the bias is
attributed in part to ISO No. 4 contracts from California
utilities in 1984 and 1985, creating a favorable energy sales
base. The commenter (IV-L-3) contended that a number of
energy projects would have likely proceeded even without the
contracts and the fact that the contracts were withdrawn does
not necessarily indicate that the trend would not continue.
The commenter (IV-L-3) also stated that the EPA
attributes bias in California to the SCAQMD landfill emission
rule. The commenter (IV-L-3) asserted that the effect of the
landfill emission rule is unclear because it falls within the
same period that ISO No. 4 were in effect. The commenter
(IV-L-3) noted that 11 facilities implemented gas to energy
projects in a similar number of years prior to either rule.
The commenter (IV-L-3) concluded that deleting California
projects will reduce bias and that eliminating them may
introduce a new bias into the data base and make it less
representative of future trends.
Response: The commenter has confused the analysis to
predict how many energy recovery projects will be in place in
the future in absence of the rule (138 landfills; as described
in the memorandum entitled "Landfill Rule Energy Recovery Cost
Analysis, December 16, 1992, Docket No. A-88-09, Item
No. IV-M-2) with the deletion of the landfills estimated to
use energy recovery in absence of the rule from the landfill
data base. The attempt to eliminate bias discussed by the
klk-85\04 2-177
-------
commenter was actually done in two analyses; however, the
commenter confuses it as being one analysis. The intent was
to eliminate the bias of landfills that would develop energy
recovery systems in absence of the rule from the landfill data
base. See the memorandum "Changes to the Municipal Solid
Waste Landfills Nationwide Impacts Program Since Proposal,"
April 28, 1993, (Docket No. A-88-09, Item No. IV-M-3). In
order to obtain this goal, an analysis had to be performed to
determine, how many landfills would develop the energy recovery
systems in absence of the rule. In this analysis the National
trends in landfill energy recovery were reviewed. The EPA
determined that, in order to use the trends as a predictor of
the future, bias had to be eliminated for special projects in
California, such as ISO No. 4 and the SCAQMD rule. The energy
recovery projects associated with ISO No. 4 were deleted from
this analysis as a reasonable estimate for the bias from both
ISO No. 4 and the SCAQMD rule, because some of the ISO
projects would have been developed anyway. The increase in
energy buyback rates in New Jersey, New York, and
Pennsylvania, mentioned by the commenter, does not introduce a
bias because these rates will fluctuate over time as they did
in the timeframe used to predict the future energy recovery
projects. Also the increased buyback rates will continue to
affect future energy recovery projects. This analysis
concluded that a yearly average of 138 landfills would apply
energy recovery in the absence of an NSPS.
As a separate step, because 138 landfills would apply
energy recovery in the absence of the rule, the 138 most
profitable landfills in the data base were removed from the
analysis to estimate the national cost and emission reduction
impacts. As explained in a previous response, it would be
inaccurate to attribute costs and emission reductions for
these landfills to the rule.
Comment; In regards to the analysis to determine the
number of gas to energy sites in the future, one commenter
(IV-L-3) asserted that a few operators of many landfills
klk-85\04 2-178
-------
dominate gas to energy projects and could be viewed to bias
the data base. The commenter (IV-L-3) maintained that
60 percent of all landfill gas is recovered for energy
purposes by just three operators. The commenter (IV-L-3)
stated that the large operators achieve a large economy of
scale because of their size and expenditures with^ vendors and
service companies.
Response: The commenter implies that there is a bias due
to landfall owners or operators that have developed a large
economy of scale for energy recovery equipment and service,
and that this bias affects the analysis used to determine the
number of landfills that would use energy recovery in the
absence of the standard. If there is such a bias, the number
of landfills predicted to install energy recovery in absence
of the standard would be overestimated and the current
nationwide impacts would be underestimated. On the other
hand, if in reality fewer owners and operators would develop
energy recovery systems in the absence of the standard, then
more energy recovery systems would be developed because of the
standard and the cost-effectiveness of the standard would be
lower. In this scenario, the current nationwide impacts would
be overestimated.
Since the cost information for energy recovery operations
was obtained from several sources, the likelihood of either
scenario has been minimized. In other words, the cost
estimates were based on cost data associated with operators of
many landfills as well as operators of few landfills. Since
the operators that maintain the majority of energy recovery
systems also own a greater number of landfills, it can be
assumed that these operators will continue to develop more
energy recovery systems at their other landfills than smaller
landfill operators. Therefore, bias in the number of
landfills installing energy recovery and the nationwide
impacts should be minimized.
kli-85\0* 2-179
-------
2.18.3 Consideration of Materials Separation
g9lpmgr)i-? Two conunenters (IV-D-18, IV-D-33) supported the
inclusion of materials separation in the NSPS. One commenter
(IV-D-33) stated that reducing the amount of waste landfilled,
especially organic wastes, would decrease LFG emissions.
However, materials such as glass, metal, and plastics, which
contribute less to gas emissions, may be better regulated
under RCRA. Six commenters (IV-D-19, IV-D-22, IV-D-26,
IV-D-27, -IV-D-29, IV-D-39) agreed with the EPA's decision not
to include such provisions. Seven commenters (IV-D-25,
IV-D-26 and IV-F-6, IV-D-27, IV-D-29, IV-D-34, IV-D-39 and
IV-F-3, IV-D-50) noted that RCRA was the proper authority for
such requirements. One of these commenters (IV-D-27) included
the arguments it had prepared in opposition to proposed
materials separation provisions for MWC's.
One commenter (IV-D-26) suggested that the EPA wait for
the RCRA reauthorization before proposing any type of
municipal landfill materials separation requirement. The
commenter recommended that the EPA take into consideration the
widespread changes a national materials separation regulation
will cause to the economy and the industrial sector. In
addition, the commenter urged the EPA only to consider the
issue of materials separation as it relates to landfill air
emissions, and to explore ways to manage nonhazardous solid
waste in a more comprehensive way.
One commenter (IV-D-19) stated that some method of
segregating toxic substances (such as batteries) in the waste
stream needed to be implemented. A second commenter
(IV-D-12), representing a trade association, stated that
80 percent of lead produced in the U.S. is used in lead-acid
batteries and that 90 percent of these batteries are recycled.
A third commenter (IV-D-17) recommended the evaluation of
reuse and recycling programs. Another commenter (IV-D-39)
stated that there are no data that they are aware of that
quantify emission reductions afforded by a materials
separation and removal requirement.
klk-85\04 2-180
-------
Response: The EPA continues to consider RCRA the
appropriate regulatory framework for material separation. The
final RCRA preamble identified an array of initiatives
designed to expand recycling efforts (56 FR 50980;
October 9, 1991). These initiatives include market studies,
federal recycling procurement guidelines, the development of
training materials for State and local recycling coordinators,
publications, and the establishment of a National Recycling
Institute,.
2.19 MISCELLANEOUS
Comment: One commenter (IV-D-9) requested that the EPA
form a technical advisory group to assist in the writing of
"more realistic" regulations. The commenter reported that
such groups are being used successfully in Florida.
Response; In developing the proposed standards, the EPA
worked closely with organizations such as NSWMA, SWANA,
SCAQMD, WMA, BFI and other government and industry
representatives. Information regarding meetings and
correspondence with these participants is documented in the
docket (A-88-09). The proposed regulation is the result of
the knowledge, expertise and data provided to the EPA by those
organizations directly affected by the standards. Comments on
the proposed standards submitted by these groups and other
commenters have been carefully considered and the EPA has made
appropriate changes to the final regulations. Therefore, the
EPA believes the regulation is realistic and has not formed a
technical advisory group for use in writing these regulations.
Comment; One commenter (IV-D-9) was in agreement with
all the public hearing comments. The commenter stated that
there are major problems in all areas of the draft regulation:
cost/benefit, health risk, field management of migration and
surface emissions versus empirical modeling, design
specifications versus performance standards, operational
requirements, and other aspects.
Response; The EPA response to specific comments from the
public hearing are provided in section 2.2.1 on health
klk-85\0* 2-181
-------
concerns, section 2.8.3 for discussion of the cost-benefit
analysis, sections 2.10 and 2.11 for modeling issues, 2.12 for
design specifications, and 2.13 for operational standards.
Comment; Five commenters (IV-D-1, IV-D-13, IV-D-15,
IV-D-40, IV-D-57) requested that the comment period be
extended an additional 30 to 90 days to allow tim,e for
additional comments on the proposed regulation.
Response; The typical comment period for an EPA
rulemaking involving complex subjects under the CAA is
60 days. The Administrator determined that a longer comment
period was not necessary, but stated that the EPA would
consider all comments received in a timely manner.
ktt-85\0* 2-182
-------
3.0 ECONOMIC IMPACTS
•«
This chapter evaluates the economic impacts of the
Slll(d) Guidelines and §111(b) Standards under the Clean Air
Act (CAA) 'that EPA has proposed for closed/existing and new
landfills. We have reviewed and made changes in our analysis
since the original draft report, "Economic Impact Analysis of
Air Emissions Controls on Municipal Solid Waste Landfills"
submitted November 1989.
The following topics are addressed in this chapter:
• waste generation and disposal as it is now practiced;
• requirements of promulgation and recordkeeping;
• characteristics and control periods of affected
landfills under present assumptions and engineering
models;
• net present value (NPV) of enterprise costs and the
costs per megagram (Mg) and per household;
• costs to society (annualized and net present value);
• emissions reductions and cost effectiveness; and
• summary of analysis, comparison of final rule options
with proposed rule options, and conclusions.
In addressing these topics, we have revised some of the
underlying assumptions concerning quantities of waste to give
better estimates of the waste flow going to landfills.
Impacts computed for the proposed rule options analysis were
estimated based on data reported in the Office of Solid Waste
(OSW) Landfill Survey.1'2 The 1986 waste flow going to
landfills reported in the survey was a particularly important
variable in determining compliance costs and emission
reductions. However, using the OSW landfill data to analyze
klk-85\0* 3-1
-------
impacts under the proposed rule options posed two problems.
First, some landfills reported their waste acceptance rate in
cubic yards, thereby creating a conversion problem from cubic
yards to tons. We had to assume a density factor for cubic
yards of waste accepted by these landfills to standardize
these values to tons of waste landfilled. The second
difficulty involved differences between the reported
historical acceptance rates (pre-1986) and the 1986 acceptance
rate. The resolution of these problems for the analysis of
the proposed rule resulted in a total municipal solid waste
(MSW) acceptance rate that was a substantial overestimate of
the national MSW generation. For the analysis of the final
rule options, we computed impacts using a revised (lower)
estimate of the landfill acceptance rate.
In addition, several changes were made to the engineering
model to give better estimates of the costs of the proposed
regulation. We also incorporated these changes into the
economic impacts analysis of the final rule options. The
following sections discuss the results from the revised models
and cost calculations.
3.1 OVERVIEW OF MUNICIPAL SOLID WASTE MANAGEMENT
3.1.1 Waste Generation
MSW is generated as a by-product of consumption and
production. Generated waste is collected and transported to a
centralized location. After collection, MSW is either
directly landfilled, incinerated in a municipal waste
combustor, or sent to a centralized recycling facility. Most
recycling and combustion residues are also sent to landfills.
MSW management uses two types o.f landfills: hazardous
waste landfills that receive both hazardous and nonhazardous
wastes and sanitary landfills. Sanitary landfills receive
nonhazardous wastes from residential, commercial, and
industrial sources and small amounts of hazardous waste
generated by small quantity generators. In this report, we
are concerned with sanitary landfills.
kl*-85\04 3-2
-------
EPA's Office of Air Quality Planning and Standards is
developing air emissions for closed/existing landfills under
§111(d) and new municipal landfills under $111(b) of the CAA.3
The CAA regulations will limit air emissions of nonmethane
organic compounds (NMOC), air toxics, odors, carbon dioxide,
methane, and other explosive gases from landfills." The
regulation will require the active collection and disposal of
air emissions.
3.1.2 Waste Disposal
Haste is disposed in sanitary landfills through a
three-step process that includes
• spreading collected waste into thin layers in the
landfill,
• compacting the layers into the smallest practical
volume, and
• covering the compacted waste with soil on a daily
basis.
After waste is deposited in the landfill, it immediately
begins to decay, producing several gaseous by-products in the
process. Landfill waste digestive processes are aerobic
(i.e., they occur in the presence of free oxygen) until nearly
all the oxygen in the waste is consumed. Waste decomposition
then changes to an anaerobic process (i.e., a process that
occurs in the absence of free oxygen). Gases produced by
decomposition migrate through landfilled waste and disperse
into the atmosphere unless emission controls are implemented.
Methane gas generated by MSW is a greenhouse gas. It is
not addressed in this report because it is not a volatile
organic compound (VOC) precursor and is not considered
hazardous to human health in the same manner as a carcinogen.
Methane is counted in the benefit-cost analysis, but the
impetus for the proposed guidelines and standards was VOCs and
hazardous air pollutants (HAPs). Therefore, we will only
address nonmethane organic compound (NMOC) generation in this
report. These compounds are VOC precursors or HAPs.
kli-85\0* 3-3
-------
Throughout this report, we discuss both new and
closed/existing landfills. New landfills are assumed to be
exactly like comparable landfills that closed during the time
period of this study. For the purposes of this study, we
assumed that, for every landfill that closed during the time
period, one exactly like it opened. *
As Figure 3-1 illustrates, NMOC generation begins slowly
as soon as waste is deposited in landfills and increases over
several years. Gas generation continues for an extended
period of time after landfills are closed and then begins to
taper off. Emission controls are required when NMOC emissions
reach a specified cutoff level. Controls must remain
operational until gas emissions decline again to the cutoff
level as gas production tapers off.
The control option discussed in this report is flares
(combustion without energy recovery). We assumed all affected
landfills choose to control their emissions in this manner,
although we expect many, if not most, of them would choose
control options that have some sort of energy recovery feature
to offset the costs of controlling emissions. This assumption
overestimates the actual costs of the regulatory alternatives
because the flare option assumes there are no offsetting
revenues. The flare option is, therefore, the most
conservative assumption.
3.1.3 Requirements of Alternatives for Promulgation
The requirements of alternatives for promulgation of the
regulation consist of a size cutoff, an emissions cutoff, and
recordkeeping requirements. Landfills affected by the
regulation are those with 1 million or more megagrams of
permitted capacity. Landfills below that size cutoff are not
expected to be subject to emissions control requirements.
In this report, EPA has evaluated three potential
emissions cutoff levels: 50, 75, and 100 Mg per year of NMOCs.
"Affected landfills" are those meeting the emissions cutoff
levels either in pre- or post-closure periods. In the most
stringent alternative, EPA will require emissions controls on
kli-85\04 3-4
-------
Emissions Produced
MgNMOC/yr
Operation of
Emission Controls
Operation of
Emission Controls
May Cease
100
Landfill First
Accepts MSW
Years Since Initial
Refuse Placement
Figure 3-1. Affected model landfill: Length of control
period tinder three stringency levels.
klk/270:BID (05/25/95)
3-5
-------
all landfills emitting 50 Mg of NMOCs per year. Less
stringent alternatives require controls at 75 Mg and 100 Mg
per year levels, respectively. High emissions cutoff levels
mean that more landfill-generated gas can be released before
emission controls must be installed and maintained.
3.2 CHARACTERISTICS OF AFFECTED LANDFILLS
3.2.1 Design Capacity *
Design capacity refers to the amount of waste that
landfills are designed to accommodate per year. Landfills
affected by the regulations vary considerably by design
capacity. Significantly fewer landfills are projected to be
affected in the final rule option than were projected in the
proposed rule option (see conclusions). Since 1989, a
permitted design capacity cutoff limit of 1 million Mg per
year has been instituted, and certain engineering parameters
and assumptions have been revised, resulting in a much smaller
affected population (see Appendix A).
Of the 7,437 landfills subject to §111(d) Guidelines,
between 4 and 8 percent would be affected depending on the
stringency level. As mentioned above, the three possible
stringency levels examined are releases of 50, 75, and 100 Mg
NMOC per year. If the most stringent 50 Mg per year
alternative were selected, 572 existing and closed landfills
would be affected. If the 75 Mg per year cutoff were
selected, 415 landfills would be affected while only 305
existing and closed landfills would be affected if the 100 Mg
per year cutoff were selected (see Table 3-1).
The §111(b) Standards apply to landfills constructed and
opened after the regulation takes effect. In this study, we
assumed these new landfills replace other landfills that
closed. Specifically, we assumed that every landfill that
closes after 1992 is replaced by an identical landfill serving
the same area. Recycling and pollution prevention efforts may
cause reduced local requirements for landfill space while
increasing and shifting populations may increase needs. We
klk-85\OA 3-6
-------
3
M
h
g
8
^^
8
^4
8
g
p
Q
B
o
|
PC
g
§
M
I
£
M
>»
1
i
•
*4
1
m
M
M
0
§
+4
•
•
^
S*
*S
o| g
1*
2 0>
•S*
u
4)
n
o
in
in —
o *•
fo *••'
in —*
-H VO
« «—
N -~
r» oo
in —
to
A
m
H
H
TJ
"M ° « X
•oo ^^
•* 7? ^"U
• ° T w 2
^_, • •-•
•+"4 «M •—
M « iH IM
i 4J -i « H
Z 0«W • 4*
g 4J-0 *<-H
• C n U
•S*; « j
IM 0 <-t a 0<
•^g> 53
«" g§ S? cow
.Lin * (N r» CM 25 3 n 09 f-i
^ :^- _, ;^, W »H »H :J. **
S^H *o? tnn" J2§ So^ 2«
S* «*i •« 5S 2^. S^
»:* s« •* S§ S^ S-*
«•>* S^ «i «2 S^. S*-«
B
35
i^
«S
•s
*) •-*
i?
• ^
«M U
*4 0)
• m m
4) o *» tog •* 0
in *H p H « M H
VI in A H «UHU
4* 14
m 4)
>£
^ ^-*
•* ~
h
0,
•
O<
C
lri
•^
T>
e
o
4J
S
•o
l-l
fl
4J
0
4>
O
4>
TJ
TJ
0
4>
O
g
r
B
M
^H
0
4J
0)
Q
•
B
V
5"
4i
e
o
u
5
o.
0
u
0
B
O
B
«
*J
8
S,
e
^4
I.
M
C
«
H
JJ
0
Z
kli-85\04
3-7
-------
realize 'that our assumption concerning new landfills may not
hold true in every case.
Mew landfills would also be subject to the regulation.
Of the approximately 944 new landfills nationwide, 89 would be
affected by the flare option if the most stringent 50 Mg per
year alternative were selected. If the 75 Mg perxyear cutoff
were selected, 56 landfills would be affected while only 33
landfills would be affected if the 100 Ng per year cutoff were
•
selected (see Table 3-2).
Tables 3-1 and 3-2 also show affected landfills
distributed according to design capacity. In both
closed/existing and new categories, the greatest number of
affected landfills are those with the smallest design capacity
(accepting < 5 Mg per year of waste). At the 50 Mg per year
level, 66 percent of the affected closed/existing landfills
are in the smallest size category. At the 75 Mg per year
level, 61 percent are below this size; 53 percent are this
size at the 100 Mg per year level. Of new landfills, 82
percent are in the smallest size category (accepting £ 5 Mg
per year of waste) at the 50 level, 82 percent at the 75
level, and 76 percent at the 100 Mg per year level.
Under all stringency levels, closed and existing private
landfills constitute a slightly larger percentage of affected
landfills than was the case before the size cutoff was
instituted (27 to 34 percent versus 22 to 31 percent). Of the
total closed/existing landfills, 104 are private at the 100
level, 121 are private at the 75 level, and 154 are private at
the most stringent emission cutoff level, 50 Mg/yr. Privately
held affected new landfills are smaller percentages of the
total affected landfills at the 75 and 100 Mg per year levels
and about the same at the 50 Mg per year level. At the 50 Mg
level of stringency, 20 of the affected new landfills are
privately owned (Appendix A and Table 3-2), 10 at the 75
level, and 6 at the 100 Mg/yr level. As previously stated,
landfills expected to have the greatest difficulty paying for
NMOC controls are those that are privately owned and already
klk-85\04 3-8
-------
00
*
M
H
to
§
3
g
X
g
fj
H
to
9
1
§
H
g
5
0
as
H
x
1
CO
•
CM
1
TABLE 3
e
0
H
•
a
i-t
•
&£
H ^J
•>. U
5 o m
W *p* f^.
OK ^
A
M
4*
CO
e
in
m
«e
in
o»
«0
•
iH
•H
•H
^ »
%4
S&
« c
iH
aff«ct«d
of total
s)
*«
O Q) -H
. O _
*-« ^^ ^^
*N — C*!**-* »2 oo?
*£. ^ Ci "* S H"
^
f»CN — ^?— C"»2 OfM
1*00^ W2. "£. «H NN
•o
^. *
>i 4J
•P 0
•H *» o
0 fl 0
• & • 4J
iMrH
3 ^ ,? 4J 0 4» «H -H -H
X> IW *• «n H O ««4 5 5
• H -— 1
id
e
a
^
•H
id
4J
0)
Q
•
CO
0)
IT
id
• 1
•y
c
Q)
U
M
Q)
a
0)
LJ
H
id
CO
0)
CO
0)
1
Q)
j^
id
a •
e e
C C
numbers j
to round i
0 Q)
£5
H *w
••
V
4J
o
kli-85\0*
3-9
-------
closed. As shown in Table 3-1, at both the 50 and 75 Mg/yr
stringency levels, 4 percent of the affected landfills are in
this category while 5 percent of the affected landfills are
closed and privately owned at the 100 level.
3.2.2 Control Periods for Affected Landfills
Landfills will be required to operate emissions controls
as long as their emissions exceed the selected cutoff level.
Individual affected landfills will reach the selected
emissions 'cutoff level in different years, depending on waste
deposited. Similarly, the number of years that emissions will
exceed the cutoff level will vary from landfill to landfill;
therefore, the year that controls may be removed will also
vary. The longer emissions must be controlled, the greater
the compliance costs and the greater the economic impacts of
the regulation (see Figure 3-1).
Tables 3-3 and 3-4 present the length of control period
for closed/existing landfills and for new landfills,
respectively. Average lengths of control periods do not vary
significantly across stringency levels in either table.
However, the distributions of landfills by length of control
period do vary widely from less than 25 years to greater than
150 years. However, at all stringency levels, half to three-
quarters of the landfills have control periods of 50 years or
less.
The ease with which landfills will be able to recapture
costs of installing and operating controls will decrease after
each landfill closes. Until that time, the landfill may
increase its user fees to offset some of its increased costs.
After closure, landfill owners must find some other way of
raising revenues. Public landfill owners may raise taxes.
Private landfills can only raise revenues through increased
user fees while they are still operating and accepting MSW.
Thus, the shorter the length of time between the start of
controls and landfill closure, the greater the financial
burden of a given control on a landfill especially if it is
privately owned.
klk-85\0* 3-10
-------
j
H
PH
i
H
H
OB
H
M
H
§
o
O
H
H
g
•i
IN
ki
2
«
0
h
§
H
PL|
»4
D
H
8
PM
O
i
t4
•
1
1
n
M
h?
i
e
e
it
r-l
•
£ ^
5 >•
"^Nfc
•k. U
n 0 «
2 £ 1"
fl S
s
2 &>
fl £
•H *
to
4*
a
e
in
CO
•
H
in
Ok
•
e
in
Ok
•
N
m
m»
5
u
••4
^^
to
Cu
control
IH
O
ft
*
v«rag« !•
(years)
<
mtn" Jjoo" «n ? i* c7 — ^ 23
r* CM 2 **> f* H C. S S
^_^ " ^_~ -_- x-* ^^ ^
^
!2 in" 2oo * rT H r7 o rr "Jo
!5n 5rg o» CM mn H r*. 12 y
^i ^_^ rt ^^^ ^_- ^^ ^"^ ~ *^
•"aT w^7 «»S* r**^ a»*~* NO
sE aE s^ «c: *£ KS
>««
>1
4>
fl
o
1»
5°
• &
i em
A e e H
fl m H
O 0 O
•H.H 004* rt
4> H ^ 4* 4» 0 «
9 -H U> M H M 4*
a«4^N « H 0 H O
«(0 VI W M H A H
sss.
• H ^
•H
Q
U
iH
id
4J
o
4J
O
4J
•d
•o
id
4J
o
c
»w_
^1
-------
tt
3
H
g
5
3
i
g
tj
|M
§
1
Q
O
H
04
j
O1"1
LENGTH OF CON!
•
*<•
n
H
*3
*
o
e
•
•
H
*~
S*
H ^J
t» O
OS £
a e **
ij
•H £
M
1 1
4*
ea
o
m
w
•
«
n
«
•
r»
m
H
•
M
*
ontrol period
o
|
H ^.
(0
• £
0»rO
« Q)
M >i
• v-'
>
<
SS ••£ «S «S «s
^^^ ^^ ^^^ ^^
V— •
in in" » 5" o oo „ ^T «2
w^r nn HH Nc!.in°
*^ *^ •-» S"
ma> «P» r»o — ^T w X
no nn HCM 'ricBS
\^ ^M# ^^ ^^ ^»
*
•H
O
|5
•&
«H ^4
^1 S
• •
»l* 0
O >i o in
A 0 0 H
fl in H
o « o
•H H O O 4* i-t
+» H ~ 4* *» «
3-H am H +>
A i
• rt '-'
•H
O
10
_J
^^
(0
i t
^
4J
•v 0
+J
2
•o
10
^
c
>1
10
a
iH
i
•^
10
4J
0)
Q
•
01
Q)
en
10
•4-1
c
-------
3.2.3 Control Periods Prior to Closure
Tables 3-5 and 3-6 show the length of control periods
prior to closure for existing and new landfills respectively.
Existing landfills average 19.7 years of control prior to
closure at the 50 stringency level, 19.3 years at the 75
level, and 21 years at the 100 level. New landfills average
12.1 years at the 50 level, 11.5 years at the 75 level, and
12.7 years at the 100 level.
Landfills with the shortest periods of control before
closure (£5 years) are those with the greatest economic
impacts under the regulation because they have the shortest
time to recover control costs by raising user fees. Affected
existing landfills in this category represent 20, 28, and 15
percent of the total affected at the 50, 75, and 100 Mg per
year levels, respectively. Affected new landfills in the < 5
years category are 28, 34, and 29 percent at the three
respective control levels (see Table 3-6).
Table 3-7 shows that affected private existing landfills
average 23.9, 25.4, and 27.5 years of control period prior to
closing at the three stringency levels. Of this subset of
existing landfills that are presumed to be the most severely
affected by the regulation, 17 percent have a control period
prior to closure of <5 years at the 50 stringency level, 21
percent are in this category at the 75 level, and 11 percent
at the 100 level.
3.3 IMPACTS OF THE REGULATION
We analyzed the economic impacts of the regulation on
existing and new landfills. Measures of these impacts include
enterprise costs (the costs to each facility), social costs
(the costs to society), recordkeeping costs, and emissions
reductions and cost effectiveness.
klk-85\0« 3-13
-------
£S
g
h
S|
^^
OS
g
o
g
H
g a
O iJ
H i-3
PS H
Pi h
O S
o2
H rf
0
P* X
»a H
o w
K H
B M
§S H
8
g
g
o
E
•4
•
1
«•»
M
»3
1
e
e
H
H ^
O >i
a a -v.
• M U
o • o m
56S *
•_. _j
H «^(
4* tr»
ea s
o
in
O *1^ ~~i _-^ ^^^
• HtrtHinrM0im*>H
ft *** *-^ N— • ^«*
rt ^ •— » •-» ,— •-» <— »
• ocor^ozjcstno
*> SN«nH2nr»fM|5n»*iH
•^ ^^ ^^ ^^ ^^
A ~
ȣ
o a^
41 • OJ
M H^
0 >i
•H A •
S. M SJ
Oi « 9
— r! •
•g HO
0 -H H
•rt «M 0
M -d
• 00
a < *>
H
0 « S
8 55
M • -H
4> 4* M
§ 8°-
o «ma
»M 0
«W ^ «^H
O (0 M
„ M >, fl H 0 N «
fl ^- O O H
• *H M O O
H « 4* 5 0 4> 4»
ij fl a jj
• 3 S o « H H
D» • -n o vi i
id
6
•H
•H
id
4J
Q)
Q
• 10
(0 rH
Q) iH
D>-H
«3 *d
c c
a) id
O iH
V4
0) T3
a
WJ
0) O
fciH
id u
to to
0) 0)
10 TJ
0) 3
x: «H
-P O
C X
0) M
tl
id
a •
o>
c c
•H-H
•o
n c
ti 3
01 O
2 14
3 0
C -P
0) 0)
X 3
&4 Tt
™ t*
a)
4J
O
2
kli-85\0*
3-14
-------
a
A
3
H
At.
M
3
g
E
"
O
M
o
h
M
I
H
|
o
M
"
g
H
§
H
PM
.3
g
B
8
8
i
»4
•
«o
1
m
M
.3
M
2
o
e
H
B
iH
•
iH
^
. rj
53 R
•
§ *
5 s
•H r*.
M
44
CO
O
M
r-
•
N
IA
•
H
H
•
(M
H
s
^4
M
•
a
ontrol
(years)
n
mgth of <
closur*
• o
H*»
• M
O> o
tfri - -•
• *H
F
<
o ST _ N" r» n" ., ^ _•
^^
w^" n? oin" oP »2
Hn rtrvi HN HH in"
"^ ^^ S^ V— ^^^
^^ ^i^ **«s
moo* r»o" r*H^ OH" «2
WN NfO Wn HH C0°
iH
O
fj
H
4*
fl
O ^
O (0
« 9
?S£
».HS
0 >,H
„ A O oo
fl o N in
O • O H
•HH 4* O O H
4* i-l O 4* 4* «
5-rt *> 4> 4*
•P H H O
•H « -rl VI « H N H
t_l «4 t •
£8S
• na
Q
a
_J
^^
10
4J
0
4J
9
4J
•o
•0
10
oj
0
c
>1
<0
B
10
(-1
•H
(0
43
0)
0
w
01
CP
(fl
•w
jj
c
0)
o
M
0)
a
0)
M
10
(0
0)
(0
0)
^4
«c
£
0)
14
10
a •
D>
c c
•H -H
numbers
to round
01 0)
x: ?
tiTJ
• •
0)
4J
O
kli-85\04
3-15
-------
s
H
H
CO
H
o
o
in
•
r»
N
e H
H H
•£ SS •*
'
•P
O
o
j
in
N
CM
SS
o o
«
a
Deta
a
o>
s
N
o
H
1
*~ 8
H (0
O V4 « "M
M 10 • O ^
*» 0) *» •
fl >, 0,13 O
•S8o
H 4)
o o
O • M
B O _ „
• o -*JH a
H 4> 4» H *-»
9
e
in
o
*»
H
M
in
A
g
4*
O
H
* H a—
*^1
Q
4J -O
C C
4) (0
O rH
(0
0) O
M rH
W U
a n
Q) Q)
(0 t3
0) 3
£ rH
•P U
C X
0) H
M
(0
C C
•H -H
•O
a c
13 o
C4,
5S
0)
I
klk-85\0*
3-16
-------
3.3.1 Enterprise Costs
In this discussion of enterprise costs, we address the
following:
• NPV of enterprise costs,
• annualized enterprise costs,
• costs per Mg of waste and costs per household, and
• recordkeeping costs.
3.3.1.1 NPV of Enterprise Costs. One measure of the
cost of complying with the regulatory alternatives under
consideration is the NPV of enterprise costs. This measure is
computed by discounting the flow of capital and operating
costs to arrive at a measure of the current value of the costs
that will be incurred throughout the control periods of the
various landfills. Because most landfills will begin and end
controls at different times, using an NPV measure of costs is
an appropriate way to compare costs between landfills.
Closed/Existina Landfills. Table 3-8 presents NPV of
enterprise costs for closed/existing landfills. The interest
rates faced by public owners of landfills differ from those
faced by private owners, so we discounted the stream of
capital and operating costs using a different discounted rate
for each ownership group. We discounted the capital and
operating compliance costs incurred by public landfill owners
using a 4 percent rate, and we discounted costs incurred by
private landfill owners to their NPV using an 8 percent rate.
Table 3-8 presents these costs, along with a distribution of
the number of affected landfills in several enterprise cost
categories for each of the three stringency levels.
The maximum NPV of enterprise costs incurred by any
closed/existing landfill is $50.3 million under the 50 Mg
stringency level, $50.1 million under the 75 Mg stringency
level, and $49.8 million under the 100 Mg stringency level.
When summed across all landfills affected by controls under
each stringency level, the national total NPV of enterprise
costs ranges from $1.37 billion under the 100 Mg stringency
level to $2.10 billion under the 50 Mg stringency level.
kli-85\04 3-17
-------
klk-85\0*
3-18
-------
NPV of enterprise costs varies from less than $500,000 to
more than $10 million at all stringency levels. At the 50 Mg
NMOC/yr level, 63 percent have an NPV of $3 million or less
while 57 percent and 48 percent of the landfills at the 75
level and 100 level, respectively, fall in this category.
Haw Landfills. Table 3-9 presents NPV of enterprise
costs for affected new landfills. As shown in the table,
89 new landfills affected by the 50 Mg level of control have
total enterprise costs of $212 million, while the 56 new
landfills affected by the 75 Mg level of stringency have an
aggregate NPV of enterprise costs of $150 million, and the 33
new landfills affected by the 100 Mg stringency level have
aggregate NPV of enterprise costs of $114 million. While the
aggregate NPV of enterprise costs are highest at the 50 Mg
stringency level, the average NPV enterprise cost per facility
for this level, $2.39 million, is lower than for the other two
stringency levels because so many more landfills with lower
costs are affected by the 50 Mg stringency level. At the 75
Mg stringency level, the average NPV enterprise cost per new
facility is $2.68 million, while the average NPV enterprise
cost per facility is $3.44 million at the 100 Mg stringency
level.
The frequency distribution of affected new landfills by
NPV of enterprise costs in Table 3-9 indicates that a higher
proportion of affected landfills under the more stringent
control alternatives experience a relatively low NPV of
enterprise costs. For example, under the 50 Mg stringency
level, 31 percent of affected facilities have an NPV of
enterprise costs of $1 million or less. Under the 75 Mg
stringency level, 24 percent have a NPV of enterprise costs of
$1 million or less, and only 23 percent have a NPV of
enterprise costs of $1 million or less under the 100 Mg
stringency level.
3.3.1.2 Annual!zed Enterprise Costs. The annualized
enterprise control cost per Mg of MSW and the annualized cost
per household for affected existing landfills are based on
klk-85\0* 3-19
-------
CO
H
t6
§
H
D
CO
§
u
O
0
n
H M
3s2 *.
M
a
o
o ^
•"o
«w
fl
-~- O 3
I • H
*>
«
o
o
fl «M *» •
o« "§ o 8 8
M rH 3 •
4JH-H «^| Bl • •
M *»
*Se
O
^^ ^^ ^"* ^^ ID
M ^ ^^ 0^ tM ^^ |M \O '^ ^J
^^ S^ ^^ ^^ ^^
«^^ ^^ ^^
•41 ^i tj0 lft *""'* ^"* *O S
•"4 Oi ("I VO ^^ ^^ •! _j
^^
^-*
^^ ^^ *^ ^^ O
HN ^*m HH WCL«S
N«^ *-* '*^' ^^
0 0 O
• • •
H -H
u s-H«a
a o h c
0) 0 O.3
MO o
CU-H M M
•d o
4i i
A rH C *
4J 1C 1C E
C U
4) TJ W
M ffl C rH
(0 -H 1C -H
&4 (0
4> (0 -P
c a -H 4)
-H O rH Q
O-H
a
-------
each landfill's NPV of enterprise costs. These costs are
annualized using the following formula:
Annual!zed NPV of _ NPV (enterprise costs)
Enterprise Costs " (i - (i+r)"1) /r)
•»
where r is the interest rate and t is time.
The interest rate and the length of time over which costs
are annualized depend on the ownership of the landfill. As
explained previously, publicly owned landfills are annualized
using a 4 percent interest rate over the time period during
which controls will be in place. Privately owned landfills,
on the other hand, will not be able to recapture their
compliance costs after they stop accepting MSW. The
enterprise costs for privately owned landfills, therefore,.are
annualized over the period from 1993 until the landfill
closes, using an 8 percent interest rate.
3.3.1.3 Cost per Ma of MSW. To compute the annualized
enterprise cost per Mg of MSW for affected existing landfills,
the annualized cost was divided by the quantity of waste
accepted by the landfill in 1986.* One measure of the average
annualized cost per Mg of waste accepted is the national
annualized cost per Mg of MSW, which is computed for each
stringency level by summing the annualized enterprise costs
for all the affected landfills at that level, and then
dividing by the summed quantities of waste accepted by all the
affected landfills in 1986. The national annualized costs per
Mg of MSW presented in Table 3-10 range from $1.22 per Mg at
the 100 Mg stringency level to $1.27 per Mg at the 50 Mg
level. Although these numbers are greater than those reported
in the proposed rule option, they are not radically different
and do not vary significantly across stringency levels.
' Aa noted in Section 3.3, the historical annual average amount of MSW
accepted by the landfill is substituted for the quantity of MSW received
in 1986 for some landfills.
kli-85\0* 3-21
-------
8
S
h
O
o
H
I
e
e
H
6
o
in
m
N
M)
CM
+*
I
o
o
M
0 >,-
.
H
0 fl D»
— -a_r, Cn rH
*••
r» *"* r* "~* *^ « o"
^>f™' N* ***'*' r* o
"•C. «2. *s_* * ^
o
moo
• t • O
o H m H
M
r-l
«H >, T3
•H rH 4)
3
0 >*rH
O«w U
. M « X
>i a £ w
rH4J *>
o «
•H O O •
•H O -P D>
A C
3 fM-H
O< * o^ *O
*rt ^^ c
M O H 3
O-H O
UtJ LJ fl Lj
So
a a r4 o
4J *o
4) O 4) TJ
a NT)
*J-H id
4> CrH
U 4) Id 4J
id O 3 O
M C C
10 4) C
4) Oi (d >i
(0 id
fl) •* 4) fi
J3 M
•P 4J Id ID
C Id rH
4) M -H
U T> r-l «J
Id 4) r-l 4J
O.N-H 4)
-H«M Q
C «H TJ •
•H id c a
3 Id « r-l
0 C r-l 4) rH
0) flj 73 3 a TJ
1 fl) C 0 C
3 M 5 H id
2 Id O O rH
fl)
o
kli-85\0*
3-22
-------
Table 3-10 also contains a frequency distribution of
affected landfills by annualized cost per Mg of MSW accepted
in 1986. At the 50 Mg stringency level, about 40 percent of
landfills experience annualized costs of $1.25 per Ng or less.
The maximum annualized cost at this level of stringency,
however, is $8 per Mg. At the 75 Mg stringency level the
maximum annualized cost falls to $7 per Mg of MSW, and the
proportion of landfills that experience costs of $1.25 per Mg
or less increases to 45 percent. Finally, at the 100 Mg
stringency level, 44 percent of affected landfills experience
annualized costs per Mg of MSW of $1.25 or less, and the
maximum annualized cost experience is only $6 per Mg.
Privately Owned Closed/Existing Landfills. The
enterprise costs for privately owned landfills were annualized
over a period beginning in 1992 and ending when the landfill
closes. Privately owned landfills can only recapture their
costs through increased user fees while they are still
accepting MSW. The shorter the period of time between 1992
and the year the landfill closes, therefore, the greater the
potential burden of a particular amount of control costs on
the landfill's owners. Tables 3-11 and 3-12 give the same
information as Table 3-10, but for privately owned landfills
that have 5 or fewer years until closure to 10 years until
closure, respectively. Table 3-11 shows that the national
annualized enterprise cost per Mg of MSW accepted for private
landfills with 5 years or less until closure is more than
three times the national annualized costs for all affected
landfills at each stringency level. Specifically, at the 100
Mg stringency level, the national annualized enterprise cost
is at the 100 Mg stringency level, the national annualized
enterprise cost is $5.42 per Mg of MSW; it is $4.20 per Mg of
MSW at the 75 Mg level, and it is $4.79 per Mg at the 50 Mg
stringency level. At the 75 Mg stringency level, 83 percent
of the 12 affected landfills that are expected to close before
1998 experience annualized costs between $3.00 and $10.00 per
Mg of MSW.
klk-85\04 3-23
-------
g
Pi«
o
H
I
in
o o o o o o
tfl
O
CM
o o
00 00
o
o
« as -H
• H ^
4*«H !£
O H CO
^S8
p
H H
O O
4» *»
m o «
N O 4*
• • o
•-I m H
•
•o oj •
0) ^ (0
r4 *4 MJ
C 3 »^
5 CO «H
O O-H
•H u-o
•HMO)
M 0) B
CU>iO
iH
u « o
O J3
C?U C
(0 -l
CO (0 >i
M (0
5 to B
ft -*
••^ "H
fi «H tO
3 -H iH
C
-------
3B ta»
4
S'E
*3
Egg
s|°
giji
8§^
„ co 5?
"^
SH >
^^ ^J
glg
& 5
SB ••
aALIZED 1
EXISTING
AND 2002
S1- «0
0»
** E4 °*
tJ *^
-£
V*
o *rf
s£
H
e
e
H
•
«
iH
a
IS
H-C
II"
2 o>
•S*
M
**
GQ
m
M
w
•
H
m
ix
•
H
«
•^
• ^
•
H
s »
s s
• o
a
£ ?•
• 9 m ~
O *»^H *
o OHM
_ • « a
« *< 3
• »j « tr
M * B S
•H -, S ^.
H » IH v>
* w o >,^-
2 a A
fl 0 ^
a u> o • m
* s -H H i
->s ** H
H^ H
^ *-» o"
e o o o * o o
>^ »_ H^
e
m e e
(M O •
• • e
H *>
0
memo
• m N e
o • • •
vi o H m
o
o
o
o
0
0
-------
For private landfills closing between 1998 and 2002, unit
control costs are not nearly as high as the unit control costs
of private landfills closing before 1998 (see Table 3-12).
The national average measure is $1.79 per Mg of MSW at the 50
Mg stringency level, $1.75 per Mg of MSW at the 75 Mg
stringency level, and only $1.62 per Mg at the 100 Mg
stringency level. At the 100 Mg stringency level, only four
landfills affected are expected to close between 5 and 10
years after 1993, and these landfills incur costs less than
$1.62 per Mg of MSW. At the 75 Mg stringency level, only four
affected landfills are expected to close between 1998 and
2002, and these landfills experience annualized enterprise
costs between $1.25 per Mg and 3.00 per Mg. At the 50 Mg
level, four landfills are expected to close between 1998 and
2002, with annualized costs between $1.25 per Mg and $3.00 per
Mg.
New Landfills. The national annualized enterprise cost
per Mg of MSW for new landfills, presented in Table 3-13, is
$0.62 at the 50 level. At the 75 level, the enterprise
control cost per Mg is $0.58, and the cost per Mg at the 100
level is $0.59. Table 3-13 also provides a frequency
distribution of affected new landfills by the annualized
enterprise cost per Mg of MSW accepted. This distribution
reveals that the higher the stringency level, the higher the
proportion of affected landfills incurring annualized costs
greater than $1.00 per Mg of MSW accepted. At the least
stringent 100 Mg cutoff level, only 23 percent of the 33
affected landfills have costs of $1.00 per Mg or higher, and
no affected landfill experiences annualized costs exceeding
$1.39 per Mg. At the 75 Mg stringency level, however, over 40
percent of the 56 affected landfills have annualized costs
over $1.00 per Mg; at this stringency level, the maximum
annualized cost is $1.41 per Mg of MSW. Finally, at the most
stringent 50 Mg level, 36 percent of the 89 affected landfills
have annualized costs of $1.00 per Mg or higher, and the
maximum annualized cost is $1.44 per Mg.
ktt-85\o* 3-26
-------
m
H
I
P)
^^
3
M
**
n
o»
e
o
H
m
**
e
M
O — ' —• «-' C.
CO -^^ *"• "^ o"
10 «^«^>HCOftH<05
• ^C.H**"N*'I'»H
*~*
^^
? *S •£ 5S SS Si
o ^^ *-* ^^
o»
X **
•
2. 8
Oi
+» « •
«4fc MB
V H --*
O *P*H ^
O O H CO
A M ' S* frw
V ** B Ol
M « fl X o e e
•n ^ 3 ^- m e o
* W O >i^ 0 H «
0!Ba O • 5 4» 4* 4»
^. *» r-i w m e e •
•-« vy a ^i o» . N in e 4*
8s— * Xi IM 3d o • • • o
•H«VI 0 0 H H
^ * M a M
•P S " H OU
0 *• ^
X O
0
M Xi
O -P
,
*J-H 73
O
2
kli-85\0*
3-27
-------
3.3.1.4 Cost per Household. This calculation attempts
to assess the annualized cost that will be borne by households
served by affected landfills. To compute this measure, the
annualized enterprise costs are divided by an estimated number
of households served by the affected landfills. The national
annualized enterprise cost per household for each stringency
level is computed by summing the annualized enterprise costs
incurred by all affected landfills at that stringency level,
and then dividing by an estimate of the total number of
households served by those landfills in 1986.
BKJftifr? Landfills. Table 3-14 presents the annualized
enterprise cost per household for affected existing landfills.
The national annualized enterprise cost ranges from $4.84 per
household at the 100 Mg stringency level to $5.02 per
household at the 50 Mg stringency level. At the intermediate
75 Mg stringency level, the national annualized enterprise
cost is $4.95 per household.
The frequency distribution of affected landfills by
annualized enterprise cost per household, also shown in Table
3-14, indicates that 23 percent of affected landfills at the
50 Mg stringency level will incur annualized enterprise costs
of $3.50 per household or less. At the 75 Mg stringency level,
24 percent of the affected landfills will incur annualized
costs of $3.50 or less per household. At the 100 Mg
stringency level, 22 percent of the affected landfills
experience annualized costs of $3.50 or less per household.
Mew Landfills. Table 3-15 assesses the potential impact
of the regulatory alternatives on the households that will be
served by new landfills based on the annualized enterprise
cost per household. The national cost per household varies
from $2.32 at the 100 Mg stringency level to $2.30 at the 75
Mg stringency level to $2.45 at the 50 Mg stringency level.
3.3.1.5 Recordkeepina Costs. All regulations impose
administrative and recordkeeping costs on affected facilities.
All facilities, including those below the size cutoff, must
file reports concerning the amount of waste they accept. We
kii-85\o* 3-28
-------
s
o
B
CO
p
o
H
P**
f .
CO CO
O t-3
H
|g
z 3
o
o g
Z
H H
CO E*
H CO
at H
cu x
t^ Q
5s H
H &4
a H
V PN
N b
H <
ANNUAL
FOR
.
t-(
A
TABLE
o
o
H
,
•
i-l
O
> •£
I-* ^j
Q
^ X K)
* i **
ta
.2 s
•H ~.
H
CO
O
m
^^
CO
j—
_
0
(V
o
IA
m
M O -5"
• OrH
a o
2?-g
g S-SS
0 OrH 0
V *! 3 -5.
• «M C V>
N « S ^
« 9* o NH
nS 3 9 3 o
SQo A IH A
* JC *H V
O • «^ M fl M
•H a v>- -P « •
41 s ^ « H a
00 •
•O tfi J3 10
ft) 4J 4^ ft)
C CO T3
^ | 0 0 3
O
>l NX
rH • O» W
O -O OH
•H 0 H
f*"4 *^H *
ja M 0 tr»
3 ft) O C
a a I<-H
*M *O
V4 r-4 C
O 0 -P 3
4J
•P MO
C -P-H 4J
ft) C H
O ft) (Q o
H O D 4J
ft) Vt C
Q» ft) C T3
Ou <0 "O
ft) 10
<0 M -P
*J «0 0
10 (0 C
o) a
tO T3 H >,
ft) ft) H
fc 3 «J -H
(X C -P 10
(0 7J ft) r-l
C ft) O r-l
•H ft) C -H
to 10 o • *d
^ ft) C
5 to >, ^ (0
43 «H PH 3 H
B iH ft) O)
3-H *J O TJ
C <*-( <0 rH ft)
•o > o to
« C-H O
H-H a o o
**
a)
4J
O
kli-85\04
3-29
-------
o
i
H
CO
&
s
gj
Pi
g4
j 3
g £
x 6
o 5
o g
m
CO R
H C
fi*
gB
M
w
Q ^1
H
Kg
i
c
2
^^
in
H
|
n
M
J
g
e
o
H
•
n
^H
• ^_^
{> t.
• >,
"CI
|ls
^ &
u^-"
4*
CO
e
w>
^ °§ °S H| ss s§
O -X —. C"
W M ^? M S" • ^ * *-* * 0
W^ N^ Hr, n^ ,„ 0
N *-< «^ C.
m ^^ *-»*"• '^ S
^* AiMJkiAjNi^cnookj-t
«MCM^ MOM „„ ^^ W0
CM «-» ^^ Jj.
M O*O
• O ^
Ot O
^^ Mtf
** *O ^5 v 0)
• i-i •MM
O O -P-H 3
Of OHO
« • «43
M .3 «i S .^ ««
** 3 "W B V> O
M o * fl ^ o o e
•H J3 H in O •
SV)- O friH H cn H
•— ' JQ O
§d ,2 o o o
<0 0 • • 4J ** -P
M H -H rH • M (-4
o ** H 3 r* in o e •
H /3 9-H O • »- IA 0 4J
S9 A
M ft
0 4>
«M
(1J
•O 10 O
§n a)
O
•HO 41
^H *^H
900).
£X ft > O>
5
O O -P T5
-i 10 *O
0) 0
O^ ^ *O CO
10 O 0 r-l
•P N 10
C 4J 'H 4J
0 CiH O
O 01 10 4J
U O 9
0 H C O
(X 0) C 4^
Q) *O
IM * 0 «O
«0 fc 10
4J 10
n 10 -P
0 to o
m -c i
4J -H i *
fi^^H
C
-------
assumed the minimal reports done by facilities below the size
cutoff does not contribute significantly to the total
recordkeeping costs, so their costs are not included here.
For facilities that must install controls, recordkeeping
costs include tracking quantities of waste received,
installing monitoring devices and tracking emissions levels,
and issuing the appropriate reports to the regulating agency.
This regulation would require many landfills to incur costs of
keeping track of the quantities of waste landfilled and the
quantities of emissions generated whether they eventually
needed to install controls or not.
EPA has established a progressive Tier System for
determining whether a particular facility is covered by the
regulation under review.5 In essence, any facilities not
exempted by the size cutoff have to ascertain by a series of
tests whether they must install controls. If testing
indicates a facility must install controls at Tier 1,
additional reporting, testing, and recordkeeping requirements
occur at Tier 2. If the facility must still control emissions
at Tier 2, additional requirements occur at Tier 3, and so on.
At each level, a facility may be exempted from controls and
further testing; however, it has already incurred the
recordkeeping costs at that level (see Table 3-16).
EPA also incurs recordkeeping costs in tracking and
monitoring facilities. Table 3-16 presents these record-
keeping costs as the agency cost. In the second half of this
table, the total cost per landfill excludes agency costs.
The table presents the recordkeeping costs for the 100
Mg/year stringency level only. The number of facilities that
must install controls is estimated to be 477 rather than 305
as stated in Table 3-1. The main reason for the difference is
that some landfills have already installed controls for a
variety of reasons. These landfills would incur no capital or
operating compliance costs as a result of the regulation, and,
therefore, would have only additional recordkeeping costs. We
also assumed in Table 3-16 that all controlled facilities
klk-85\04 3-31
-------
!
s
H
&
H
8
§
ve
H
I
m
S
H
ff
4»
g
^
a
&
i<
&
4>
«
9
•a
a
H
*^
E
*
n
ff»
0
rH
in
r>
vo
3
r>
a»
eg
in
In
o
9t
^
n
H
eg
*
CT>
eg
D>
C
•H
a
OJ
Q)
M
o
o
OJ
*t4
rH
rH
•H
•0
C
id
•H
1
1— (
rH
0
M (0
4J 4J
C (0
0 0
U 0
(^
o\
^
in
H
o
00
r>
n
O)
r>
00
rH
^
,_(
n
H
"8
4J
B
0)
X
0)
(0
rH
rH
•H
*W
•O
C
id
rH
^
O
10
(0 rH
0
O (H
0)
rH'H
id EH
4J
04J
H id
00
at
0
,4"
VO
OA
rH
^
eg
«*
r>
CM
^
^i
o
N
«»
in
H
Q)
4J
Oh
0
OJ
X
0)
U
rH
rH
•H
*4H
•o
C
id
rH
M
O
00
^
VO
in
(Q
4J
(Q
O
U
O^
c
•H
8*
OJ
3
>H
0
U
OJ
M
rH
id
4J
6-1
in
M
VO
id n
vo
o\
00
in
o
o
VO
O
o\
n
rg
r>
oo
«T>
s
r> rg «»
r> in o
* in eg
id
o oj
s
*O
oj
o> x
N OJ
(0 H
rH
^i **H
oj id
>>
O)
o
in
o
in
o
eg
n
eg
H eg
o o
o eg
*O
OJ
•O
OJ
•
§• t
X
0)
*o
C
id
S
0)
*o
C
•
«gl
a
-------
would incur all of the recordkeeping costs whereas, in
reality, that may not be necessary, some facilities,
correctly assuming that they must install controls, may skip
directly to Tier 3.
Recordkeeping costs are expected to be only about
3.5 percent of the total enterprise costs per landfill.
Therefore, they have been addressed separately and are not
included in the estimated impacts presented in other sections
of this report.
3.3.2 Social Costs
Social costs are those costs borne by society as a whole.
They include investment and consumption foregone in the
private sector by virtue of using private sector resources for
public purposes. This analysis presents an estimate of social
costs of the final rule for landfills. Note that these
estimates do not reflect the benefits to society resulting
from a change in air quality. We used social costs in our
estimates of cost effectiveness.
3.3.2.1 NPV of Social Costs. A measure of the potential
cost to society of complying with the regulatory alternatives
is the NPV of social costs. This measure is computed by first
annualizing capital costs and then discounting the flow of
capital and operating costs. The resulting figure is a
measure of the present value of the costs that will be
incurred throughout the control periods for the various
landfills. A net present value measure of costs is the
appropriate way to compare costs between landfills because
most landfills will begin and end controls at different times.
The NPV of social costs presented below are computed using a 7
percent discount rate.
Closed/Existing Landfills. When summed across all
affected landfills under each stringency level, the national
total NPV of social costs ranges from $1.085 billion under the
100 Mg stringency level to $1.662 billion under the 50 Mg
stringency level (see Table 3-17). Although more landfills
are affected under the more stringent 50 Mg level than under
klk-85\0* 3-33
-------
r««
H
AS
in
r-
o
m
9
H
?
2
dhA «k
W ^1
in n
m
m
m
** *•-» _
•H (4 « 4*
I D.»*»
I « O.O •
IUOH tr
5^ §
i
4jrt^
3f-l O
AIM o
•H"O •
4» ««M
• HO
M
vi
S253 2S 53 S^gl
«_*<_* oM>JgoTinH>»^wg
"^«|£,Hi'0^lH^'l«H
0
o o o •
« • . o
H m in H
o o o o
4* 4* 4* 4* H
m O O O O 4*
• •••HO
o H m m AH
O
•H4J
10
•H-0
CM O
0 C
0) >i
> a
f^
•P-H
C <0
OI-P
a a)
0)Q
4J flj
•4J
a c
fl) 3
* t*en
+J C C
C-H-H
0) WO
to 9 C
aT3 0
0) M
C4J
•H 3 O
a-P
m e
U O fl)
fl) O 3
^ T3
B a
g-H to
C iH
•P 10
fl) W-P
£00
EH O4J
4)
O
%
kli-85\0*
3-34
-------
the other two stringency levels, a larger proportion of
affected landfills incurs relatively lower NPV of social costs
($3 million or less) under the 50 Mg level than under the
75 Mg level or the 100 Mg level. The mean NPV of social
costs per affected landfill under the 100 Mg stringency, $3.56
million, exceeds the mean NPV of social costs for the other
two stringency levels. '*
Mew Landfills. Table 3-18 presents the NPV of social
costs for affected new landfills. Total social costs increase
as the level of stringency increases. At the most stringent
50 Mg cutoff level, the aggregate total NPV of social costs,
$1.34 billion, is about twice the aggregate total NPV of
social costs at the 100 Mg level, $72 million. The aggregate
total NPV of social costs at the 75 Mg level, $95 million,
lies between the cost of the other stringency levels. The
number of affected landfills increases substantially as the
stringency level increases, and the average NPV of social
costs per landfill decreases as the level of stringency
increases. The frequency distribution in Table 3-18 shows
that 96 percent of new landfills have an NPV of 3 million or
less at the 50 Mg/yr level, while 93 percent have social costs
of this size at the 75 level and 88 percent at the 100 level.
3.3.2.2 Annual!zed Social Costs.
Closed/Existing Landfills. Annualizing the NPV of social
costs provides another measure of the cost to society of the
regulatory alternatives under consideration. We annualized
the NPV of the social cost of each affected landfill over the
years from 1992 to the end of the landfill's control period
using a 7 percent discount rate; then we summed these
individual annualized values to get the total annualized
social cost. The resulting total annualized social cost for
affected closed and existing landfills for each stringency
level is the following:
• $128 million for the 50 Mg stringency level,
• $103 million for the 75 Mg stringency level, and
• $83 million for the 100 Mg stringency level.
klk-85\04 3-35
-------
s
H
3
2
fe
s
g
o
Su
5j*
3
*
a
«
Jjj
H
8
OB
g
_
2
g
*^
1
at
K
S
^ ^
g
CO
n
a
o
o
H
•
H
• ^
• *"•
H^!
B S **
•
||
4j
a
o
in
j
4
«
C
4
a
3S« ^
i
Ok
in n J| •
IN IA in •
H H
8,
o
v4 ^A ^"^
v> a"o
>- OH
Ovy
Q ^^
4> H
O -H!H
O C^ *fl4
S5
I-J -s
0 *4» 4>H
•H M « 4» •
H flu • 4> 4t
flO^H &•
O « IH
** •«
« >
S 2
^^
cr *~ > <> ^r* —• *^ <-»«»o
CO N VO 2 N VO OO N VO nO
^— • "•* \ ^,,
oPc.?«N'Mc-as>Mc:wi>
rtH T>1«*1 N W* ^^ OO N^1 |O
^^
*~* *~* •"» ^_^ ^^ ,_^ Q
HH WN 5S «^ °a ••« «s
*— * ^— ' **-» ^^^
41
9
^
$
4»
fl
5?°°
O M H
4» 4> H
4* H-H « 4
9-H O • 0 0 0 0 0 4»
A IH O ° • * • * •"* O
•H Q « VI O H (•) « A t«
H fl
4» 0 »<
• HO
^4
O
H O
«4>
O *O
a 10
B
a
C-H
0 «
0 0
WO
0.
4> 0
SCrt
l§
« o
4> tO
C-H
ttt)
o
At ^J
O< 0)
o
0 h
J^ 0
io a
a t-»
0
a (0
0
x>< ty^ o^
4J C C
C -H -H
0 WO
M 9 C
a-o o
0 >-i
•H 3 o
»t^
k 0 0
0 O 3
M *O
I a
3 -H Q
C rH
4J 10
A| ffl ^J
£ O O
H O4*
• •
0
4>
O
2
kli-85\0*
3-36
-------
Thus, the annualized social cost of the 75 Mg stringency
level is 24 percent higher than the annualized social cost of
the 100 Mg stringency level. The annualized social cost of
the 50 Mg stringency level is 24 percent higher than the
annualized social cost for the 75 Mg stringency level.
Mew Landfills. The total annualized social cost for
affected new landfills for each stringency level fs the
following:
• $10.mi11ion for the 50 Mg stringency level,
• $7 million for the 75 Mg stringency level, and
• $5 million for the 100 Mg stringency level.
As expected, the least stringent regulatory alternative
(the 100 Mg stringency level) has the lowest annualized social
cost, and the most stringent regulatory alternative (the 50 Mg
stringency level) has the highest annualized social cost.
3.3.3 Emissions Reduction and Cost Effectiveness
Although we are considering the costs of complying with
the §111(d) and lll(b) final rule options, we must also
consider the cost effectiveness of these alternatives. Cost
effectiveness is measured as the annualized compliance cost
per Mg of reduction in the emission of NMOCs. We express
cost-effectiveness ratios as national figures. The sum of all
compliance costs for all affected landfills is divided by the
sum of emissions reductions for all affected landfills. In
addition, we calculated the incremental cost effectiveness or
the change in cost effectiveness as the stringency level
increases.
3.3.3.1 gmi!ssjons Reduction of Closed/Existing
Landfills. Table 3-19 shows the emissions reductions
resulting from the three regulatory alternatives under the
flare option. Total undiscounted NMOC emissions reductions
range from 4.4 million Mg at the 100 Mg stringency level, to
4.8 million Mg at the 75 Mg stringency level, to 5.3 million
Mg at the 50 Mg stringency level. The emissions reductions
are spread over the period of time during which the affected
landfills are using the flare emission controls. In order to
kli-85\0* 3-37
-------
§
H
D CO
1
H
CO
COO
SE
OB
hH
CO iJ
g°
^g
5>
in
(
2
O
ss
m
N
CO
m
r»
N
r*
0
O >i« a
_.*- S^- 8 a* -«•«
« as o ^ a Mf-i
id a • a o • e
4IQ «O-^O«-»-H»-tfl^3 0
0 • 0
fl -H > -H
D a < a
*- -- ^ ~ mo
IH n co oi fi ^^ w ^^ M ^
-
* P o —' ^^ ««<•
0
o o o
o o o
00*.
«, K O
N 10 rt
o o o
4* 4* 4* 0
0 0 0 0 H
000 « «
00004*
«.«.«. H O
H CM Ut A 6*
C4J
O O
•H e
at
ID >i
•H 10
§ B
at
ID -H
ID ^ ^3
0) C
MT3 3
0) 0) O
5^M
CrH O
a> 3-P
M U
(0-H Q)
CU<0 3
o-o
c
•H ID in
•H rH
ID (0
h M4J
OJ C 0
5 04J
S-H
94* 0
C O4J
w *o *o
£0)13
§5 i* to
«
o
2
kli-85\04
3-38
-------
compare emissions reductions with the costs from
Section 3.3.2.1, we discounted the NMOC emissions reductions
using a 7 percent rate of discount. The discounted NMOC
emissions reductions range from 1.2 million Mg at the 100 Mg
stringency level to 1.3 million Mg at the 75 Mg stringency
level to 1.4 million Mg at the 50 Mg stringency level. The
average discounted NMOC emission reduction decreases as the
stringency level increases, because the number of affected
landfills increases faster than the NMOC emissions reductions.
Thus, the*average NMOC emission reduction per affected
landfill is 3,873 Mg at the 100 stringency level, 3,071 Mg at
the 75 Mg stringency level, and 2,381 Mg at the 50 Mg
stringency level.
Cost Effectiveness of Closed/Existing Landfills. He
combined measures of NMOC emissions reductions with the
discounted NPV of social costs presented in Table 3-17 to
estimate the cost effectiveness of the flare option for
closed/existing landfills. At the top of Table 3-20 is the
national cost effectiveness of each stringency level, computed
by dividing the aggregate NPV of total social cost by the
total discounted NMOC emissions reduction. The national cost
effectiveness of the flare option at the 100 Mg stringency
level is $918 per Mg of NMOC reduced. At the 75 Mg stringency
level, the national cost effectiveness is $1,051 per Mg of
NMOC reduced, and the national cost effectiveness is $1,220
per Mg of NMOC reduced at the most stringent 50 Mg level.
The frequency distribution of affected landfills by cost
effectiveness (Table 3-20) demonstrates that as the stringency
level decreases, an increasing proportion of landfills has a
cost effectiveness under $1,000 per Mg of NMOC reduced. At
the 50 Mg stringency level, only 17 percent of affected
landfills have cost-effectiveness measures that low, while 23
percent of affected landfills fall below $1,000 per Mg of NMOC
at the 75 Mg stringency level. Finally, 32 percent of the
affected landfills have a cost effectiveness less than $1,000
per Mg of NMOC at the 100 Mg stringency level. At the bottom
klk-85\04 3-39
-------
to
H
1
e
0
H
in
r»
e
in
•
9^ ^^ *n ^^ ^^ ^^
H ^ ^
°^ * ™ S^ 3n "!£•
H
e ^ ___ ^
N S»H *n *5 5^,
H s-» — ^
CO ^-»
• u
S * 1
1 3 *
•H vi n>
** • as e
O "H 4* Z*. e e e
• - e o e
«M M O <-- O O *
• «H • W in H
8" 8*8 5 S 5
o o o « • o
o ac -Hrt > o e o o
S 4>H AIM O H •> « ••
^X-H«CfVI H M M
O<^ M 8*4
4*^ can's
« -H
X Q
-B(^
^. « o
o o o o |
N«* ' %
~. in
*-. in o in
N H HO 1-
*— M
*-* in
*°^ MH *t
•«— «0
•
^J
o
IM
IM
0)
^J
i^
S ng
°. -3 5g
e 4* fl
H 0 • 0
A H j|
14 i •
SO^
4JH
> CO 1
•H O r>
«*» o-o
^ 0) 3 C
<0 CTJ 3
Q) O
CO (U V4 )><
tt) 4-> C O
« OP
jCJ O^"^
4J C ID 0)
C-H CO 3
0) •O-H *O
V4-H )8
« > Q> CO
•O O «J
••J *W%* O
^^ ?•> fr*
Q
LlTjTJ O
: The nunbe
calculate
discounte
not add t
0)
4J
o
2
klk-83\04
3-40
-------
of the table, incremental cost effectiveness measures the
change in national cost effectiveness experienced as the
stringency level increases first from 100 Mg to 75 Ng and then
from 75 Mg to 50 Mg. As the stringency level increases from
100 Mg to 75 Mg, the incremental cost effectiveness is $2,755
per Mg of NMOC reduced. Moving from 75 Mg to 50 Mg results in
an incremental cost effectiveness of $3,655 per Mg of NMOC
reduced.
B»jfff j.on Reduction of Mev Landfills. Table 3—21 shows
the emissions reductions for new landfills under the flare
control option. The first line shows the total undiscounted
NMOC emissions reductions at each stringency level. These
measures, showing the total emissions reductions achieved
throughout the control period for all affected new landfills,
range from 0.42 million Mg at the 100 Mg stringency level, to
0.49 million Mg at the 75 Mg stringency level, to 0.58 million
Mg at the 50 Mg stringency level.
The discounted NMOC emission reduction, when summed
across all affected landfills, ranges from 0.73 million Mg at
the 100 Mg stringency level to 0.82 million Mg at the 75 Mg
stringency level to 0.94 million Mg at the 50 Mg stringency
level.
The average discounted NMOC emission reduction per
affected landfill is much higher at the 100 Mg stringency
level than at the 50 Mg stringency level because the number of
affected landfills falls faster than discounted NMOC reduction
as the stringency level decreases. At the 100 Mg stringency
level, the average discounted NMOC emission reduction is 2,196
Mg of NMOC, more than two times the average discounted NMOC
emission reduction per landfill at the 50 Mg stringency level
(1,060 Mg of NMOC). At the 75 Mg stringency level, the
average discounted NMOC emission reduction, 1,455 Mg of NMOC
per affected landfill, falls between the average emission
reduction values of the other two stringency levels. The
frequency distribution of affected new landfills by discounted
NMOC emission reduction shows that the proportion of landfills
kli-85\OA 3-41
-------
I
H
I,
CO »4
S
IS
OB h
H*
I
H
H C
10
a >•
0
a
4-1 iH
O-H
(0
OI4J
+J 0)
C4J
a> id
a u
a)
*1
4> O
0) U
2 CO
0) C
o>a>
« o
4J Vl
IJL
« tr •
M C D>
*-H C
UJ-H
s3?
0
jj id
CrH
0 3
0) O
O
4J
e
e
e
«
o
*
4»
O
Idr-l 0
aid 3
o-o
•H a a
I W4J
c o
I O4J
•H
4J O
104,
:^?
i M id
0)
4J
O
kli-85\0*
3-42
-------
achieving relatively greater NMOC emissions reduction
increases as the stringency level decreases.
Cost Effectiveness of New Landfills. We can construct
cost-effectiveness measures for affected new landfills toy
combining information about emission reductions (presorted i
Table 3-21) for new landfills with information about the NPV
of social costs (Table 3-18). As presented in Table 3-22 this
value ranges from $997 per Mg of NMOC reduced at the 100 Mg
stringency level, to $1,160 per Mg of NMOC at the 75 Me level,
to $1,427" per Mg of NMOC at the 50 Mg stringency level. The
frequency distribution demonstrates that, as with close:'/
existing landfills, the proportion of affected new land.f ills
having cost-effectiveness measures less than $2,000 per Mg of
NMOC increases as the degree of stringency decreases. At the
50 Mg stringency level, only 28 percent of landfillr have a
cost effectiveness under $2,000 per Mg of NMOC, while at the
75 Mg stringency level, 38 percent have a cost effectiveness
of $2,000 per Mg or less. At the 100 Mg stringency level,
65 percent of affected landfills have a cost effectiveness
under $2,000 per Mg.
The last line of Table 3-22 shows incremental cost
effectiveness for new landfills (i.e., the change in cost
effectiveness experienced as one moves from the 100 Mg
stringency level to the 75 Mg level, and then from the 75 Mg
stringency level to the 50 Mg stringency level). As the
stringency level decreases from 100 Mg to 75 Mg, the
incremental cost effectiveness is 2,460 per Mg of NMOC
reduced. The incremental cost effectiveness of moving from
the 75 Mg stringency level to the 50 Mg stringency level is
3,184 per Mg of NMOC reduced.
Flexibility Analysis of 1980 requires Federal agencies to
determine if regulations will have a "significant economic
impact on a substantial number of small entities." EPA
guidelines on determining whether a regulatory flexibility
analysis is required defines a "substantial number1* as 20
klk-85\04 3-43
-------
n
•*
j
H
N
3
5
g
4
i
s
5
I
K
g
(0
00
a
S
&*
D
H
s
H
H
1
M
1
S
"
e
e
rl
.
•I
H
H ^J
58 M
r
M
00
e
M
s •£ s§
e ^ ^
2 — *•«*•
H CO H H ^
H *"* ""
N *-» iv nT
t "2. HH
H *""
41 O
fl ti as
• 9 Z
> 4»
^« t% ^^
"H O o\
** • X
O »M 4> <. 0
«4 MO-" O
• «M • N
*» — ° i?S o
• O fi fl +»
80 o • • o
r -HrH > o e
g 4»H ** S «H
P^ «H«
0 •*
* 0
a|-S -s sf i
^^
^S -K *"* °
nco MC'«!»'-( *S IS
p»«n W2, °PJ «2 *
"~ ^ »— «
as •£ *s s° 5
^"* ^"^ **1-' 1*1
«l
1
tH
4>
0
•
e «H
e o «M
o e •
e »
» 0 4*
in H •
0,
i
o o o
4» 4» 0
O fl
0 0 0 H «
00 » « 4*
0 0 0 4* fl
* «H 0 «
(M M A H 1
^
C
C
H
A
n
i-H
•H
(0 0 4-1
Q
a >i
0 A •
C <-
0 4J N
> a i
•H O r>
- 4J o
o *d
0 r-l C
"W-H
0 O CO
O -1
4J a i
n n
O *M
u o w
0
0
c c a>
0) 0) ^>
o to
U 0 C •
0 n o cr
QuCX-H C
4J'H
0 4J O-O
M 0 3 C
«J C TJ 3
0 O
W 0 M V^
0 43
01 4J C O
0 O 4J
43 O^*H
4J C 10 0
C -H to 3
0 >O -H -O
« > 0 (0
•O O (0
C O -P
•H >,ac o
43 S -P
0 0 0 4J
45 4J 4J
§ A) C *O
3 H 3 T3
C 3 O (0
0 0
0 i-t ID 4J
43 «-H O
H O -d C
,,
0
4J
O
*
kli-85\0*
3-44
-------
percent of all affected entities. Neither the proposed rule
options nor the final rule options will affect a substantial
number of small entities under these guidelines.
Nevertheless, an analysis of the impacts on households and
government jurisdictions was performed for the proposed rule
options. The cost per household and the cost per Mg computed
for the final rule options are not significantly different
from those presented for the proposed rule. Consequently, a
revised distributional analysis is not warranted.
3.4 COSTS OF REGULATIONS AFFECTING LANDFILLS
Landfills and their close substitutes municipal waste
combustors (MWCs) are both subject to regulations that are in
the final stages of development. In particular, the municipal
waste combustor regulation, which will regulate the
incineration of municipal solid wastes (MSW), increases the
costs of providing MWC services. The air pollution regulation
for landfills, analyzed in this report, is similarly expected
to increase the costs of providing landfill services.
Because the regulations are still under development, we
do not know their final form or the exact costs that will be
associated with them. However, we expect the MWC regulatory
costs to be higher than the landfill air emission costs.
Therefore, we expect the share of waste going to MWCs to
decline and the share of waste going to landfills to rise.
Based on the expected relative magnitudes of the
compliance costs of the two regulations, the expected market
adjustments resulting from the interaction of these
regulations are illustrated in Figures 3-2 and 3-3. In each
figure, DI and S2 show the demand and supply for the waste
disposal service in the absence of the regulation. D2 and S2
show the demand and supply with the regulations in effect.
Demand and supply for MWC services is presented in
Figure 3-2. The supply curve, Si, is expected to shift
upwards substantially to S2 due to increased MWC regulatory
costs.
klk-85\0* 3-45
-------
$/Mg
(P)
Q2 Q, Qa
Mg of MSW
(Q)
Figure 3-2. Expected impacts of coata of regulations on
municipal waate combustors.
$/Mg
(P)
Q2 Q3
Mg of MSW
(Q)
Figure 3-3. Expected impacts of costs of regulations
on sanitary landfills.
W2TO:BID (05/25/95)
3-46
-------
Th..s shift results in an increase in price (P2) and a decrease
in quantity cf MWC services (Q2) . Sanitary landfills (Figure
3-3) also are expected to experience a decrease in supply due
to the costs of air emission controls (S3 to Sj), but this
shift is expected to be smaller than that experienc^c by MKCs
because the compliance costs are thought to be lower. The
shift results in an increase in price (P2) and a corresponding
decrease in quantity of landfill services demanded (Q2).
Demand for a good or service depends, among other things,
on the prices for substitutes. KWC and sanitary landfill
services are considered to be close substitutes. Generators
of KSW n,ay choose to either landfill their solid waste or to
incinerate it. However, because of transportation costs,
legal restrictions on shipments of solid wastes, and the
geographical distribution of MWC and sanitary landfill
facilities, they are not perfect substitutes. Because they
are close substitutes, the increased prices desc_ioed above
rer it in changes in demand for the substitute services. The
increased price of landfill services is expected to increase
the demand for MWC services and vice versa. The increased
demand for MWC services (D2 in Figure 3-2) results in another
increase in price and a small relative increase in quantity
(P3 and Q3). The increased price of KWC services ;suits in
increased demand for landfill services. This increased demand
will result in both higher prices and higher quantities for
landfill services (Q3 and P3 in Figure 3-3).
Overall, both the MWC regulations and the landfill
regulations increase the cost of disposing of MSW. The
overall quantity of waste disposal is expected to decline,
other things being equal. Because the compliance costs
associated with the MWC regulation are expected to be larger
than the compliance costs associated with the landfill
regulations, the relative share of waste sent to MWCs is
expected to fall and the relative share of waste landfilled is
expected to increase. In the illustrations presented here,
the absolute quantity of landfill services with both
-B5\04 3-47
-------
regulations in effect is greater than it was at baseline.
Whether the absolute quantity will in fact be greater or less
is an empirical issue, but the share of waste being sent to
landfills should increase.
3.5 SUMMARY AND CONCLUSIONS
We focused our economic analysis on the flare option for
• \
controlling NMOC emissions from closed/existing and new
landfills. The flare option assumes that all affected
landfills will control NMOC emissions using flares, which
*
overestimates the actual cost of the regulatory alternatives
because some landfills will choose a cheaper energy recovery
option.
As discussed in Section 3.1, two features of the
engineering costing model are noteworthy for the economic
analysis. First, the model assumes that landfills that close
between 1987 and 1997 are replaced by an identical landfill
serving the same area, even though recent evidence indicates
that the number of U.S. landfills is actually declining. The
model also uses relatively high MSW acceptance rates, which
are important parameters in determining NMOC emissions rates
and the cost of emissions controls. These features lead to
overestimates of the number of affected landfills, compliance
costs, and emissions reductions.
In summary, the actual economic impacts of the Slll(d)
and lll(b) regulatory alternatives under consideration are
probably less than the economic impacts presented in this
chapter. Nevertheless, our analysis of these regulatory
alternatives leads to several specific conclusions:
• The regulatory alternatives will affect only a small
fraction of the closed/existing and new landfills
(generally less than 10 percent), and most of the
affected landfills are small (less than 5 million Mg
capacity).
• The number of affected closed private landfills, which
have no way of generating revenues to cover compliance
costs, is small under the flare option.
kli-85\0* 3-48
-------
• The national NPV of enterprise costs decreases
substantially as the stringency level decreases under
both control options for affected closed/existing and
new landfills, but the average enterprise cost rises as
the stringency level decreases.
• The national arnualized enterprise cort.ro! cost per Mg
of MSW is below $1.30 p?r Kg for all stringency levels
under the flare option tcr affected existing and new
landfills.
• The costs of the regulatory alternatives are very low
for most households — the majority of affected existing
landfills : i\'s compliance costs wide- $€.00 per
household per year and the majority c- affected new
landfills have compliance costs under $2.50 per
household per year .
• Although the national cost effectiveness of all the
stringency levels under the flare option is less than
$1,500 per Mg of NMOC emissions reduction, cost
effectiveness varies greatly among affected landfills-
much more than is typical for EPA
• The regulatory alternatives under consideration for
closed/existing and new landfills will not affect s
substantial number of small entities, so a Regulatory
Flexibility Analysis is not required for either the
§111 (d) or lll(b) rulemakings. Nevertheless, the
analysis of the proposed rule options included a
distributional analysis of the impacts on affected
households and government entities. The cost per
household and the cost per Mg computed for the final
rule options are not significantly different from those
presented for the proposed rule. Consequently, a
revised distributional analysis is not warranted.
• The social costs of the regulatory alternatives for
affected closed/existing and new landfills are very
sensitive to the discount rate because of the long
control periods under stringency levels for both the
flare and energy recovery control options.
In general, the economic impacts of the §111 (d) and
lll(b) regulatory alternatives on households and
municipalities are too small to significantly influence the
choice among these alternatives. Privately owned landfills
that are already closed and must install emissions controls
may be significantly affected by the regulatory alternatives
because they have no way of recovering their compliance costs.
3-49
-------
However, very few closed, privately owned landfills are
affected under any of the regulatory alternatives. The
control costs of the regulatory alternatives at affected
landfills will probably not lead to a significant shift in NSW
flows from landfills to municipal waste combustors. Finally,
all of the regulatory alternatives will stimulate the adoption
• \
of energy recovery technologies at affected landfills.
Table 3-23 compares the estimated impacts computed for
the proposed rule and those computed for the final rule. Note
that the emission cutoff levels evaluated under the.proposed
rule option (25, 100, and 250 Ng NMOC) differ from those under
the final rule option (50, 75, and 100 Hg NMOC). Since the
100 Mg stringency level is the only one analyzed for both the
proposed and final rule options, it is the level presented and
compared in Table 3-23. Consequently, comparisons of the
impacts under the proposed and final options should be made
with the understanding that the stringency levels evaluated
are different under the two analyses. Four of the measures
presented in Table 3-23 are particularly relevant for
comparison of impacts under the two analyses: number of
affected landfills, total compliance cost, total emission
reduction, and cost effectiveness.
The estimated number of potentially affected landfills is
lower under the final rule than the proposed rule. This
difference results from the revised waste flow estimates and
revised engineering assumptions used to compute impacts for
final rule (see discussion in Section 3.1). Furthermore, the
size cutoff for landfills with an acceptance rate below l
million Mg of MSW per year excludes some landfills from the
analysis of impacts under the final options that were affected
under the proposed rule. The difference in the number of
affected landfills results in differences in the estimated
compliance costs and the estimated emission reductions as
described below.
This analysis presents two measures of total compliance
costs: NPV of social costs and NPV of enterprise costs.
kli-8S\0* 3-50
-------
TABLE 3-23. SUKJ4ARY OF DX??E&EN€£S B1TWEBH THE PROPOSED RULB
AND FINAL RULE OPTIONS AT THB 100 MO PER YEAR
STRINQSMCY LEVEL
Category
Number of Affected Landfills:
closed/existing
new
Average Control Period
(years) :
closed/existing
new
Total NPV of Average
Enterprise Costs for Affected
Landfills ($/landf ill) :
closed/existing
new
Annualized Control Cost per
Household ($ per household) :
closed/ exist ing
new
National Emissions Reductions
(Mg NMOC per year) :
closed/ exist ing
new
National Cost Effectiveness
($/Mg NMOC) :
closed/ exist ing
new
National NPV of Total
Enterprise Cost ($) :
closed/ exist ing
new
National NPV of Total Social
Costs ($) :
closed/ exist ing
new
Proposed Rultt
option
853
104
66.3
59.6
$4,260,000
$3,920,000
$4.90
$2.78
28,600,000
2,330,000
$640
$1,081
$3,634,000,000
$407,000,000
$7,157,000,000
$896,000,000
Final Rul*
Option
305
33
51,8
38.6
$4,490,000
S3.44C.OOO
$4.84
$2.32
4,396,000
419,000
$918
$997
$1,370,000,000
$114,000,000
$1,085,000,000
$72 , 000, 000
kLk-85\04
3-51
-------
Under both cost measures the impacts estimated for the final
rule are lower than those estimated for the proposed rule.
Enterprise costs are lower because fewer landfills are
affected under the final rule.
Social costs are lower for two reasons. As is true for
the estimate of enterprise costs, social costs are lower
•«
because fewer landfills are affected under the final rule.
Second, the NPV of social costs under the final rule is
computed based on a 7 percent discount rate while the
corresponding measure for the proposed rule was computed using
a 3 percent discount rate. Using a higher discount rate
results in an NPV of social costs that is substantially lower,
even on a per-landfill basis. We used a different discount
rate for our analysis of social costs under the final rule to
reflect recently revised OMB guidance on the appropriate
social discount rate.
Emission reductions are lower under the final rule than
under the proposed rule. The difference in undiscounted
emission reductions is attributable to the difference in the
number of affected landfills. Discounted emission reductions
are lower under the final rule because fewer landfills are
affected and the discount rate used is higher.
Finally, cost effectiveness is computed as the NPV of
social costs divided by the discounted emission reduction.
Because both costs and emission reductions are proportionately
lower under the final options, cost effectiveness is not
significantly different.
klk-85\0* 3-52
-------
3.6 REFERENCES
1. U.S. Environmental Protection Agency. Background
Document for the Solid waste Dilemma: An Agenda for
Action. Draft Report of the Municipal Solid, Waste Task
Force, Office of Solid Waste, U.S. Environmental
Protection Agency. September 1988.
2. U.S. Environmental Protection Agency. National Survey of
Solid Waste (Municipal) Landfill Facilities. Prepared by
Westat, Inc. EPA 68-01-7359, September 1988. p. 7-3.
3. Federal Register. Standards of Performance Proposed
Rule. 56:104. May 30, 1991.
4. Morris, G. E., B. L. Jeliicorse, K. B. Heller, T. P.
Neely, and T.H. Bingham. Economic Impact of Air
Pollutant Emission Standards for New Municipal kaste
Combustors. Research Triangle Institute. Final report
prepared for Office of Air Quality Planning and
Standards, U.S. Envircnacntal Protection Agency, Research
Triangle Park, NC. August 198S. p. 3-1.
5. Reference 3.
6. Memorandum, from Pelt, R., Radian Corporation, to Curtis-
Powell, S., Research Triangle Institute. July 15, 1593.
Recordkeeping costs.
klk-85\0* 3-53
-------
TECHNICAL REPORT DATA
•'ts'.'.'ZV'^ns on tn« reverse &**ore completing)
'l No.
EPJ-.-4S3/R-94-021
3. RECIPIENTS ACCESSION SO.
4. TTOE AND SUBTTTIE
Air Emissions from Municipal Solid Waste
Landfills^-Background Information for
Final Standards and Guidelines
5. REPORT DATA
December 1995
6. PERFORMING ORCtf-N 2ATON CODE
7. AUTHOR(S)
6. PERFORMING ORGANIZATION
NO.
3. PERFORMING l^GANIZATION NAME AND ADC3"SS
Office of Air Quality Planning and
Standards
U.S. Environmental Protection Agency
Research Trrangle P&rk, N.C. 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRAN! NO
68-D1-C1.17
12. SPONSOWNQ AGENCY NAME AND ADDRESS
Director, Office of Air Quality Planning
and Standards
Office of Air and Radiation
U.S. Environmental Protection Agency
Research Triangle Fsrk, N.C. 27711
13. TYPE OF REPORT AND PSKOD COVERET
14. SPONSORING AGE:
------- |