EPA-453/R-95-0136
Municipal Waste Combustion:
Background Information Document for
Promulgated Standards and Guidelines
-- Public Comments and Responses
Emission Standards Division
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
October 1995
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TABLE OF CONTENTS
Page
1.0 OVERVIEW 1-1
2.0 PUBLIC COMMENTS 2-1
2.1 List of Commenters 2-1
2.2 Organization of Comment Summaries 2-17
2.3 List of Acronyms and Abbreviations for Units of
Measure 2-19
3.0 NEW SOURCE PERFORMANCE STANDARDS -
MUNICIPAL WASTE COMBUSTOR EMISSIONS 3-1
3.1 Selection of Source Category 3-1
3.2 Selection of Affected Facilities 3-22
3.3 Modification and Reconstruction 3-24
3.4 Selection of the Maximum Achievable Control
Technology Floor for Municipal Waste Combustor
Emissions 3-26
3.4.1 General Comments on MACT Floor Selection 3-26
3.4.2 Municipal Waste Combustor Organics . . . 3-33
3.5 Selection of Maximum Achievable Control
Technology for Municipal Waste Combustor
Emissions 3-33
3.5.1 General Comments on Emission Limits . . 3-33
3.5.2 Municipal Waste Combustor Organics . . . 3-35
3.5.3 Municipal Waste Combustor Metals (Other
Than Mercury) and Particulate Matter . . 3-38
3.5.4 Municipal Waste Combustor Metals
(Mercury) 3-41
3.5.5 Nitrogen Oxides 3-45
3.5.6 Good Combustion Practices 3-47
3.5.7 Size Categories for New Municipal Waste
Combustor Plants 3-67
3.6 Impacts of Municipal Waste Combustor Emissions
Standards 3-68
3.6.1 Environmental 3-68
3.6.2 Cost and Economic 3-70
3.7 Selection of Format of Proposed Standards for
Municipal Waste Combustor Emissions 3-80
iii
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3.8 Performance Test Methods and Monitoring
Requirements for Municipal Waste Combustor
Emissions 3-83
TABLE OF CONTENTS
(CONTINUED)
Page
3.8.1 Periodic Testing 3-83
3.8.2 Continuous Monitoring 3-86
3.8.3 Proposed Test Methods 3-91
3.9 Reporting and Recordkeeping Requirements for
Municipal Waste Combustor Emissions 3-93
3.10 Startup, Shutdown, and Malfunction Provisions . 3-95
3.11 Legal Considerations 3-98
4.0 MUNICIPAL WASTE COMBUSTOR NEW SOURCE PERFORMANCE
STANDARDS - SITING REQUIREMENTS 4-1
4.1 Siting Analysis 4-1
4.1.1 Selection of Siting Analysis
Requirements 4-1
4.1.2 Public Meeting Provisions for Siting
Analysis 4-5
4.1.3 Reporting and Recordkeeping Requirements
for Siting Analysis 4-6
4.1.4 Legal Authority to Issue Siting Analysis
Requirements 4-7
4.1.5 Applicability of the Siting Requirements 4-13
4.1.6 Miscellaneous 4-15
4.2 Materials Separation Plan 4-16
4.2.1 Selection of Materials Separation Plan
Requirements 4-16
4.2.2 Impacts of Materials Separation Plan
Requirements 4-27
4.2.3 Compliance Provisions for Materials
Separation Plan Requirements 4-29
4.2.4 Public Meeting Provisions for Materials
Separation Plan Requirements 4-30
4.2.5 Legal Authority to Issue Materials
Separation Plan Requirements 4-33
4.2.6 Overall Agency Strategy to Promote
Municipal Solid Waste Reduction and
Recycling 4-35
4.2.7 Miscellaneous 4-36
iv
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5.0 NEW SOURCE PERFORMANCE STANDARDS -
FUGITIVE ASH EMISSIONS 5-1
5.1 Selection of Fugitive Ash Emission Limits . . . 5-1
5.2 Format of Fugitive Ash Standards 5-2
5.3 Legal Authority to Promulgate Fugitive Ash
Standards 5-3
TABLE OF CONTENTS
(CONTINUED)
Page
5.4 Miscellaneous 5-10
6.0 MISCELLANEOUS COMMENTS ON MUNICIPAL WASTE COMBUSTOR
NEW SOURCE PERFORMANCE STANDARDS 6-1
6.1 Health Effects of Dioxins/Furans and Mercury . 6-1
6.2 Procedural 6-3
7.0 EMISSION GUIDELINES - MUNICIPAL WASTE COMBUSTOR
EMISSIONS 7-1
7.1 Selection of Source Category 7-1
7.2 Selection of Designated Facilities 7-4
7.3 Modification and Reconstruction 7-5
7.4 Selection of Maximum Achievable Control
Technology Floor for Municipal Waste Combustor
Emissions 7-7
7.4.1 General Comments on MACT Floor Selection 7-7
7.4.2 Municipal Waste Combustor Metals
(Mercury) 7-15
7.4.3 Nitrogen Oxides 7-16
7.5 Selection of Maximum Achievable Control
Technology for Municipal Waste Combustor
Emissions 7-18
7.5.1 General Comments on Emission Levels . . 7-18
7.5.2 Municipal Waste Combustor Organics . . . 7-20
7.5.3 Municipal Waste Combustor Metals
(other than Mercury) and Particulate
Matter 7-25
7.5.4 Municipal Waste Combustor Acid Gases . . 7-28
7.5.5 Nitrogen Oxides 7-30
7.5.6 Good Combustion Practices 7-36
7.5.7 Municipal Waste Combustor Metals
(Mercury) 7-45
v
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7 . 6
Impacts of Municipal Waste Combustor Emission
Guidelines 7-48
7.6.1 Energy 7-48
7.6.2 Cost and Economic 7-49
7.7 Performance Test Methods and Monitoring
Provisions for Municipal Waste Combustor
Emissions 7-61
TABLE OF CONTENTS
(CONTINUED)
Page
7.7.1 Continuous Monitoring 7-61
7.7.2 Comments on Proposed Test Methods . . . 7-63
7.8 Enforcement, Reporting, and Recordkeeping
Provisions for Municipal Waste Combustor
Emissions 7-65
7.8.1 Enforcement 7-65
7.8.2 Reporting and Recordkeeping 7-66
7.9 Legal Considerations 7-66
7.10 Compliance Times for Municipal Waste Combustor
Emissions 7-71
8.0 EMISSION GUIDELINES - MATERIALS SEPARATION PLAN . . 8-1
9.0 EMISSION GUIDELINES - FUGITIVE ASH EMISSIONS .... 9-1
10.0 MISCELLANEOUS COMMENTS ON MUNICIPAL WASTE COMBUSTOR
EMISSIONS GUIDELINES 10-1
10.1 Procedural 10-1
10.2 Miscellaneous 10-1
11.0 WITHDRAWAL OF THE 1991 MUNICIPAL WASTE COMBUSTOR
EMISSION GUIDELINES (SUBPART Ca) 11-1
12.0 UNFUNDED MANDATES REFORM ACT AND EXECUTIVE ORDER
12875 12-1
vi
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LIST OF TABLES
Page
1-1 SUMMARY OF STANDARDS FOR NEW MWC'S (SUBPART Eb) . . 1-2
1-2 SUMMARY OF GUIDELINES FOR EXISTING MWC's (SUBPART Cb) 1-8
2-1 LIST OF COMMENTERS ON PROPOSED NEW SOURCE PERFORMANCE
STANDARDS AND EMISSION GUIDELINES FOR MUNICIPAL WASTE
COMBUSTORS 2-2
2-2 LIST OF COMMENTERS ON PROPOSED WITHDRAWAL OF THE
1991 SUBPART Cb EMISSION GUIDELINES FOR MUNICIPAL
WASTE COMBUSTORS 2-15
3-1 MWC II/III EMISSION GUIDELINES: AVERAGE ANNUAL
ENTERPRISE COSTS FOR PUBLIC ENTITIES 3-72
3-2 LANDFILL TIPPING FEES AT SELECTED STATES IN THE
EASTERN U.S 3-7 6
3-3 AVERAGE COSTS OF WASTE-TO-ENERGY TECHNOLOGIES . . . 3-77
vii
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1.0 OVERVIEW
On September 20, 1994, the Environmental Protection
Agency proposed standards of performance for new municipal
waste combustors (MWC's) and emission guidelines for existing
MWC's under authority of section 129 of the Clean Air Act
(Act). Public comments were requested on the proposal in the
Federal Register. The EPA received a total of 153 letters
commenting on the proposed standards and guidelines, submitted
mainly by elected officials, State agencies, environmental
groups, MWC owners and operators, industry trade associations,
and MWC and air pollution control technology vendors.
Significant changes to the proposed MWC standards and
guidelines are summarized and responses to each are in this
document. This summary of comments and responses serves as
the basis for the revisions made to the standards and
guidelines between proposal and promulgation. Refer to the
preamble to the final standards and guidelines for an
abbreviated summary of the significant issues and changes to
the proposed standards and guidelines. Additionally, a
summary of the final standards is provided in table 1-1 of
this document, and a summary of the final guidelines is
provided in table 1-2 of this document. All significant
changes made since the September 20, 1994 proposal are marked
in tables 1-1 and 1-2 with the symbol.
1-1
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TABLE 1-1. SUMMARY OF STANDARDS FOR NEW MWC's (SUBPART Eb)a
(* indicates a significant change since proposal)
Applicability
The final standards apply to new MWC units located at
plants with capacities to combust greater than 35 Mg/day
of residential, commercial, and/or institutional discards.
Industrial manufacturing discards are not covered by the
standards. Any medical, industrial manufacturing,
municipal, or other type of waste combustor plant with
capacity to combust greater than 35 Mg/day of MSW and with
a federally enforceable permit to combust less than
10 Mg/day of MSW is not covered.*
Plant Size (MSW combustion
capacity)
< 35 Mg/day*
> 35 Mg/day but
< 225 Mg/day (referred to
as small MWC plants)
> 225 Mg/day (referred to
as large MWC plants)
Good Combustion Practices
o Applies to large and small MWC plants.
o A site-specific operator training manual is required
to be developed and made available for MWC personnel.
o The EPA or State MWC operator training course must be
completed by the MWC chief facility operator, shift
supervisors, and control room operators.
o The ASME (or State-equivalent) operator certification
must be obtained by the MWC chief facility operator
(mandatory), shift supervisors (mandatory), and
control room operators (optional).*
Requirement
Not covered by
standards
Subject to provisions
listed below
Subject to provisions
listed below
1-2
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TABLE 1-1. SUMMARY OF STANDARDS FOR NEW MWC's (SUBPART Eb)a
(CONTINUED)
o The MWC load level is required to be measured and not
to exceed 110 percent of the maximum load level
measured during the most recent dioxin/furan
performance test.
o The PM control device inlet flue gas temperature is
required to be measured and not to exceed the
temperature 17°C above the maximum temperature
measured during the most recent dioxin/furan
performance test.
o The CO level is required to be measured using CEMS,
and the concentration in the flue gas is required not
to exceed the following:
Averaging
MWC type CO level time
Modular starved- 50 ppmv 4-hour
air and excess-
air
Mass burn waterwall
and refractory
Mass burn rotary
refractory
Fluidized-bed
combustion
Pulverized coal/RDF
mixed fuel-fired
Spreader stoker
coal/RDF mixed
fuel-fired
RDF stoker
10 0 ppmv
10 0 ppmv
10 0 ppmv
150 ppmv*
150 ppmv*
150 ppmv
4-hour
4-hour
4-hour
4-hour
24-hour
24-hour
MWC Organic Emissions (measured as total mass
dioxins/furans)
1-3
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TABLE 1-1. SUMMARY OF STANDARDS FOR NEW MWC's (SUBPART Eb)a
(CONTINUED)
o Dioxins/furans (performance test by EPA Reference
Method 23)
Large and small MWC
plants
13 ng/dscm total mass
(mandatory) or
7 ng/dscm total mass
(optional to qualify
for less frequent
testing)*,b
o Basis for dioxin/furan
limit
GCP and SD/FF/carbon
inj ection
MWC Metal Emissions
PM (performance test by EPA Reference Method 5)
Large and small MWC
plants
24 mg/dscm
(0.010 gr/dscf)*
o Opacity (performance test by EPA Reference Method 9)
Large and small MWC
plants
10 percent (6-minute
average)
Cd (performance test by EPA Reference Method 29)
Large and small MWC
plants
0.020 mg/dscm
(8.7 gr/million dscf)*
o Pb (performance test by EPA Reference Method 29)
Large and small MWC
plants
0.2 0 mg/dscm
(87 gr/million dscf)*
Hg (performance test by EPA Reference Method 29)
Large and small MWC 0.080 mg/dscm
plants (35 gr/million dscf)
or 85-percent
reduction in Hg
emissions
1-4
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TABLE 1-1. SUMMARY OF STANDARDS FOR NEW MWC's (SUBPART Eb)a
(CONTINUED)
Basis for PM, opacity, Cd, Pb, and Hg limits
Large and small MWC
plants
See basis for
dioxin/furan limit
MWC Acid Gas Emissions
o SO2 (performance test by CEMS!
Large and small MWC
plants
30 ppmv or 80-percent
reduction in SO2
emissions
HC1 (performance test by EPA Reference Method 26)
Large and small MWC
plants
25 ppmv or 95-percent
reduction in HC1
emissions
o Basis for SO2 and HC1
limits
See basis for
dioxin/furan limit
Nitrogen Oxides Emissions
o NOx (performance test by CEMS!
Large MWC plants
Small MWC plants
o Basis for NOx limit
Large MWC plants
Small MWC plants
150 ppmv, except
180 ppmv is allowed
for the first year of
operation*
No NOx control
requirement
SNCR
No NOx control
requirement
1-5
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TABLE 1-1. SUMMARY OF STANDARDS FOR NEW MWC's (SUBPART Eb)a
(CONTINUED)
Fugitive Ash Emissions
o Fugitive emissions (performance test by EPA Reference
Method 22)
Large and small MWC
plants
Visible emissions less
than 5 percent of the
time from the ash
transfer system except
during maintenance and
repair activities*
o Basis for fugitive
emissions limit
Wet ash handling or
enclosed ash handling
Siting Requirements
o Large and small MWC
plants
(1) Siting analysis*,
(2) materials
separation plan, and
(3) public meetings
(including response to
comments)
Performance Testing and Monitoring Requirements
o Reporting frequency
Annual (semiannual if
violation)*
Load, flue gas
temperature
Continuous monitoring,
4-hour block
arithmetic average
CO
CEMS, 4-hour block or
24-hour daily
arithmetic average, as
applicable
o Dioxins/furans, PM, Cd, Pb, HC1, and Hg
1-6
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TABLE 1-1. SUMMARY OF STANDARDS FOR NEW MWC's (SUBPART Eh)
(CONTINUED)
Large MWC plants Annual stack test
(see reduced testing
option for low
emitters of
dioxins/furans)*
Small MWC plants
Annual or third year
stack test*
o Opacity
COMS (6-minute
average) and annual
stack test
o S02
CEMS, 24-hour daily
geometric mean
N0X (large MWC plants
only)
CEMS, 24-hour daily
arithmetic average
Fugitive ash emissions
Annual test
* = a significant change since proposal, and the change is
discussed in this preamble.
a All concentration levels in the table are corrected to
7 percent 02, dry basis.
b Although not part of the dioxin/furan limit, the limit of
13 ng/dscm total mass is equal to about 0.2 to 0.3 ng/dscm
TEQ. The optional reduced testing limit of 7 ng/dscm
total mass is equal to about 0.1 to 0.2 ng/dscm TEQ.
1-7
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a
(* indicates a significant change since proposal and
the change is discussed in this preamble)
Applicability
The final guidelines apply to existing MWC's located at
plants with capacities to combust greater than 35 Mg/day
of residential, commercial, and/or institutional discards.
Industrial manufacturing discards are not covered by the
guidelines. Any medical, industrial manufacturing,
municipal, or other type of waste combustor plant with
capacity to combust greater than 35 Mg/day of MSW and with
a federally enforceable permit to combust less than
10 Mg/day of MSW is not covered.*
Plant Size (MSW combustion
capacity) Requirement
< 35 Mg/day*
> 35 Mg/day but
< 225 Mg/day (referred to
as small MWC plants)
> 225 Mg/day (referred to
as large MWC plants)
Good Combustion Practices
Not covered by guidelines
Subject to provisions
listed below
Subject to provisions
listed below
Applies to large and small MWC plants.
A site-specific operator training manual is
required to be developed and made available for MWC
personnel.
The EPA or a State MWC operator training course
would be required to be completed by the MWC chief
facility operator, shift supervisors, and control
room operators.
1-8
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a (CONTINUED)
o The ASME (or State-equivalent) provisional and full
operator certification must be obtained by the MWC
chief facility operator (mandatory), shift
supervisors (mandatory), and control room operators
(optional).*
o The MWC load level is required to be measured and
not to exceed 110 percent of the maximum load level
measured during the most recent dioxin/furan
performance test.
o The maximum PM control device inlet flue gas
temperature is required to be measured and not to
exceed the temperature 17°C above the maximum
temperature measured during the most recent
dioxin/furan performance test.
o The CO level is required to be measured using a
CEMS, and the concentration in the flue gas is
required not to exceed the following:
Averaging
MWC Type CO level time
Modular starved- 50 ppmv 4-hour
air and
excess-air
Mass burn
waterwall and
refractory
Mass burn rotary
refractory
Fluidized-bed
combustion
10 0 ppmv
10 0 ppmv
10 0 ppmv
4-hour
24-hour
4-hour
Pulverized coal/ 150 ppmv* 4-hour
RDF mixed
fuel-fired
1-9
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a (CONTINUED)
Spreader stoker
coal/RDF mixed
fuel-fired
2 00 pprnv^
24-hour
RDF stoker
Mass burn rotary
waterwall
2 0 0 ppmv
2 50 ppmv
24-hour
24-hour
MWC Organic Emissions (measured as total mass
dioxins/furans)
o Dioxins/furans (performance test by EPA Reference
Method 23)
Large MWC plants
MWC units utilizing
an ESP-based air
pollution control
system
60 ng/dscm total mass
(mandatory) or 15 ng/dscm
total mass (optional to
qualify for less frequent
testing)*,c
MWC units utilizing
a nonESP-based
air pollution
control system
30 ng/dscm total mass
(mandatory) or 15 ng/dscm
total mass (optional to
qualify for less frequent
testing)*,c
Small MWC plants
125 ng/dscm total mass
(mandatory) or 30 ng/dscm
total mass (optional to
qualify for less frequent
testing)*,c
Basis for dioxin/furan limits
Large MWC plants
GCP and SD/ESP or GCP and
SD/FF, as specified above
Small MWC plants
GCP and DSI/ESP
MWC Metal Emissions
1-10
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a (CONTINUED)
o PM (performance test by EPA Reference Method 5)
Large MWC plants 27 mg/dscm
(0.012 gr/dscf)
Small MWC plants 7 0 mg/dscm
(0.030 gr/dscf)*
o Opacity (performance test by EPA Reference Method
9)
Large and small MWC 10 percent (6-minute
plants average)
o Cd (performance test by EPA Reference Method 29)
Large MWC plants 0.040 mg/dscm
(18 gr/million dscf)
Small MWC plants 0.10 mg/dscm
(44 gr/million dscf)
o Pb (performance test by EPA Reference Method 29)
Large MWC plants 0.49 mg/dscm
(200 gr/million dscf)*
Small MWC plants 1.6 mg/dscm
(700 gr/million dscf)
o Hg (performance test by EPA Reference Method 29)
Large and small 0.080 mg/dscm
MWC plants (35 gr/million dscf) or
85-percent reduction in
Hg emissions
o Basis for PM, opacity, Cd, Pb, and Hg limits
Large MWC plants GCP and SD/ESP/CI or GCP
and SD/FF/CI
Small MWC plants GCP and DSI/ESP/CI
1-11
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a (CONTINUED)
MWC Acid Gas Emissions
o SO2 (performance test by CEMS)
Large MWC plants 31 ppmv or 75-percent
reduction in SO2
emissions*
Small MWC plants 80 ppmv or 50-percent
reduction in SO2
emissions
1-12
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a (CONTINUED)
o HC1 (performance test
Large MWC plants
Small MWC plants
o Basis for SO2 and HC1
Large and small
MWC plants
Nitrogen Oxides Emissions
o N0X (performance test
Large MWC plants
Mass burn waterwall
Mass burn rotary
waterwall
Refuse-derived fuel
combustor
Fluidized bed combustor
Mass burn refractory
Other
Small MWC plants
o Basis for N0X limits
Large MWC plants
by EPA Reference Method 26)
31 ppmv or 95-percent
reduction in HC1
emissions*
250 ppmv or 50-percent
reduction in HC1
emissions
limits
See basis for MWC metals
by CEMS)
2 0 0 ppmvb
2 50 ppmvb
2 50 ppmvb
2 4 0 ppmvb
No NOx control^
requirement
2 0 0 ppmvb
No NOx control
requirement
SNCR
1-13
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a (CONTINUED)
Refractory MWC plants
No NOx control
requirement
Small MWC plants
No NOx control
requirement
Fugitive Ash Emissions
o Fugitive Emissions (performance test by EPA
Reference
Method 22)
Large and small plants
Visible emissions
5 percent of the time
from ash transfer systems
except for maintenance
and repair activities*
o Basis for fugitive
emission limit
Wet ash handling or
enclosed ash handling
Performance Testing and Monitoring Requirements
o Reporting frequency
o Load, flue gas
temperature
Annual (semiannual if
violation)*
Continuous monitoring,
4-hour block arithmetic
average
CO
CEMS, 4-hour block or
24-hour daily arithmetic
average, as applicable
Dioxins/furans, PM, Cd, Pb, HC1, and Hg
Large MWC plants
Annual stack test*
Small MWC plants
Annual or third year
stack test
Opacity
COMS (6-minute average)
and annual stack test
1-14
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a (CONTINUED)
o
S02
CEMS, 24-hour daily
geometric mean
o
NOx (large MWC
plants only)
CEMS, 24-hour daily
arithmetic average
o
Fugitive ash
emissions
Annual test*
Compliance Schedule
o
Large MWC plants
State plans are required to include one of the following
three retrofit schedules for compliance with regulatory
requirements: (1) Full compliance or closure within
1 year following EPA approval of the State plan;
(2) full compliance in 1 to 3 years following issuance
of a revised construction or operation permit if a
permit modification is required or 1 to 3 years
following EPA approval of the State plan if a permit
modification is not required, provided the State plan
includes measurable and enforceable incremental steps of
progress toward compliance; or (3) closure in 1 to
3 years following approval of the State plan, provided
the State plan includes a closure agreement. If a State
plan allows the second or third scheduling options
(i.e., more than 1 year), the State plan submitted to
EPA must contain post-1990 test data for dioxins/furans
for all MWC units at large plants under the extended
schedule. (See § 60.21(h) of subpart B of 40 CFR 60 for
additional information relating to measurable and
enforceable incremental steps of progress toward
compliance).
o Small MWC plants
State plans must require full compliance or closure with
regulatory requirements in 3 years or less following
issuance of a revised construction or operation permit
if a permit modification is required, or within 3 years
following EPA approval of the State plan if a permit
modification is not required.
1-15
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a (CONTINUED)
o State plans are required to specify that all MWC's
at large MWC plants for which construction was
commenced after June 26, 1987 comply with the
guidelines for Hg and dioxins/furans within 1 year
following issuance of a revised construction or
operation permit if a permit modification is
required, or within 1 year following EPA approval
of the State plan, whichever is later.
o State plans are required to specify that owners or
operators of MWC's comply with the operator
training and certification requirements by 6 months
after startup or 1 year after State plan approval
by the EPA, whichever is later, for large plants
and by 6 months after startup or 18 months after
State plan approval by the EPA, whichever is later,
for small plants.
* = significant change since proposal, and the change is
discussed in this preamble.
a All concentration levels in the table are converted to
7 percent O2, dry basis.
1-16
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TABLE 1-2. SUMMARY OF GUIDELINES FOR EXTSTTNG MWC's
(SUBPART Cb)a (CONTINUED)
State plans may allow NOx emissions averaging between
existing MWC units at a large MWC plant. The daily
weighted average NOx emissions concentration from the
MWC units included in the emissions averaging plan must
comply with the following 24-hour limits: 180 ppmv for
mass burn waterwall combustors; 220 ppmv for mass burn
rotary waterwall combustors; 230 ppmv for
refuse-derived fuel combustors; 220 ppmv for fluidized
bed combustors; and 180 ppmv for other combustor types
(excluding mass burn refractory combustors). Refer to
the regulatory text of the emission guidelines for
additional requirements. State plans may also
establish a program to allow emissions trading between
non-contiguous MWC plants. Such a program shall meet
the requirements of the Open Market Trading Rule of
Ozone Smog Precursors, proposed August 3, 1995
(60 FR 39668) as finally promulgated.
Although not part of the dioxin/furan limit, the
dioxin/furan total mass limits of 30 ng/dscm,
60 ng/dscm, and 125 ng/dscm are equal to about 0.4 to
0.7 ng/dscm TEQ, 0.8 to 1.3 ng/dscm TEQ, and 1.8 to
2.8 ng/dscm TEQ, respectively. The optional
reduced testing limits of 15 ng/dscm and 30 ng/dscm
total mass are equal to about 0.2 to 0.3 ng/dscm TEQ
and 0.4 to 0.7 ng/dscm TEQ, respectively.
1-17
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2.0 PUBLIC COMMENTS
2.1 LIST OF COMMENTERS
The public comment period was from September 20, 1994 to
November 21, 1994. A total of 153 letters commenting on the
proposed standards and guidelines were received: 95 were
received on or before November 21, 1994, and 58 were received
after November 21, 1994. Comments were submitted by elected
officials, State agencies, environmental groups, MWC owners
and operators, industry trade associations, and MWC and air
pollution control technology vendors. These comments have
been placed in the dockets for these rulemakings (docket
No. A-90-45, category IV-D and docket No. A-89-08, category
VI-B). Docket A-90-45 contains comments on the proposed New
Source Performance Standards (NSPS) and emission guidelines.
Docket A-89-08 contains comments on the proposal to withdraw
the 1991 emission guidelines (subpart Ca). Many of the
comment letters submitted to docket A-89-08 also address the
proposed NSPS and emission guidelines and are included in the
responses to comments on the proposed NSPS and emission
guidelines whether they were submitted to A-89-08 or A-90-45.
Tables 2-1 and 2-2, respectively, present a listing of all
persons submitting written comments to each docket, their
affiliation, and the recorded docket item number assigned to
each comment letter.
2-1
-------
TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45)
Item No.
Commenter and Affiliation
IV-D-01
T.A. Threet
The Dow Chemical Company
Midland, Michigan
IV-D-02
D. Anetha Lue
Montenay International Corp.
Miami, Florida
IV-D-03
W.H. Long
PEDCO Inc.
Cincinnati, Ohio
IV-D-04
F.P. Osman
Evergreen Environmental, Inc.
Harrisburg, Pennsylvania
IV-D-05
F.P. Osman
Evergreen Environmental, Inc.
Harrisburg, Pennsylvania
IV-D-06
Mayor L. Gray
City of Stewartville
Stewartville, Minnesota
IV-D-07
R. Magid
Private Citizen
Royal Oak, Michigan
IV-D-08
Mayor W. Bussell
City of Eyota
Eyota, Minnesota
IV-D-09
C. Scott Daniels
Dutchess County Resource Recovery
Agency
Poughkeepsie, New York
IV-D-10
H.B. Thomas, Berry, Moorman, King
&
Hudson
Submitting on behalf of the City <
of
Madison Heights
Madison Heights, Michigan
i—i
<
i
0
1
I—1
I—1
Mayor C. Hazama
City of Rochester
Rochester, Minnesota
IV-D-12
G.L. Moilanen
Sierra Environmental Engineering,
Inc.
Costa Mesa, California
2-2
-------
TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No. Commenter and Affiliation
IV-D-13 J.S. Austin
Refuse-Fired Steam Generating Facility
City of Hampton
Hampton, Virginia
IV-D-14 T. Gray, Perkin Elmer
Real-Time Systems Division
Norwalk, Connecticut
IV-D-15 W. Dean
Applied Automation/Hartmann & Braun
Bartlesville, Oklahoma
IV-D-16 M. Benoit
(Facsimile of Cement Kiln Recycling Coalition
IV-D-78)a Washington, D.C.
IV-D-17 H.S. Cole
Henry S. Cole & Associates, Inc.
Washington, D.C.
IV-D-18 A.M. Szurgot
American Ref-Fuel
Houston, Texas
IV-D-19 D.S. Dee, Carlton, Fields, Ward,
Emmanuel, Smith & Cutler, P.A.
Submitting on behalf of the Osceola
Power Limited Partnership
Tallahassee, Florida
IV-D-20 C.R. Doolittle, D.W. Gustafson and
T.L. Threet
The Dow Chemical Company
Midland, Michigan
IV-D-21 S.E. Ellis
Cadence Environmental Energy, Inc.
Michigan City, Indiana
IV-D-22 Deleted from Docket A-90-45, comment
intended for another docket
IV-D-23 Deleted from Docket A-90-45, comment
intended for another docket
IV-D-24 D. Driesen
Natural Resources Defense Council
Washington, D.C.
2-3
-------
TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No.
Commenter and Affiliation
IV-D-25
IV-D-26
IV-D-27
(Identical to IV-D-26)^
IV-D-28
IV-D-29
IV-D-30
IV-D-31
IV-D-32
IV-D-33
IV-D-34
IV-D-35
IV-D-36
(Facsimile of IV-D-78)a
C.J. Curran and D. Lucas
Department of Solid Waste Management,
Montgomery County
Dayton, Ohio
D.B. Shea
American Plastics Council
Washington, D.C.
D.B. Shea
American Plastics Council
Washington, D.C.
L. Naake, D. Borut, and H. Hickman
The Solid Waste Action Coalition
Silver Spring, Maryland
D.A. Wizda
American Society of Mechanical
Engineers International
New York, New York
The American Society of Mechanical
Engineers
Washington, D.C.
N.H. Nosenchuck
Association of State and Territorial
Solid Waste Management Officials
Washington, D.C.
J.C. Smith
Institute of Clean Air Companies
Washington, D.C.
R. Kaufman and A. Schaffer
American Forest & Paper Association
Washington, D.C.
J.F. Marcus
Department of Law, City of Chicago
Chicago, Illinois
J. Greenberg
Browning-Ferris Industries
Washington, D.C.
M. Benoit
Cement Kiln Recycling Coalition
Washington, D.C.
2-4
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No. Commenter and Affiliation
IV-D-37 R.S. Broom, Verner, Liipfert,
Bernhard, McPherson and Hand
Washington, D.C.
Submitting on behalf of Pinellas
County, Florida
IV-D-38 R.S. Broom, Verner Liipfert, Bernhard,
McPherson, and Hand
Washington, D.C.
Submitting on behalf of the City of
Tampa, Florida
IV-D-39 D.S. Dee, Carlton, Fields, Ward,
Emmanuel, Smith & Cutler, P.A.
Submitting on behalf of the Okeelanta
Power Limited Partnership
Tallahassee, Florida
IV-D-40 Mayor M. Krause
City of Oronoco
Oronoco, Minnesota
IV-D-41 J.T. Hestle, Jr.
Nashville Thermal Transfer Corporation
Nashville, Tennessee
IV-D-42 M.F. Sterna
Private Citizen
Madison Heights, Michigan
IV-D-43 M. A. Gagliardo
Northeast Maryland Waste Disposal
Authority
Baltimore, Maryland
IV-D-44 J.T. Cochran and T. Henderson
The United States Conference of Mayors
Washington, D.C.
IV-D-45 J.G. Brody
Tellus Institute for Resource and
Environmental Strategies
Boston, Massachusetts
IV-D-4 6 B. McHenry
Cemtech, L.P.
Westchester, Illinois
2-5
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No.
Commenter and Affiliation
IV-D-47
0. Brenning for Clark County Citizens
Against Incinerator Dangers
Springfield, Ohio
IV-D-48
D. Copeland
Occidental Chemical Corporation
Niagara Falls, New York
IV-D-49
E. Berman and A. Johnston
Molten Metal Technology
Waltham, Massachusetts
IV-D-50
C.R.M. Ehlhardt
Eli Lilly and Company
Indianapolis, Indiana
IV-D-51
R.H. Colby and D.F. Theiler
State and Territorial
Air Pollution Program Administrators
and the Association of Local Air
Pollution Control Officials
Washington, D.C.
IV-D-52
(Facsimile of IV-D-87)a
W.R. Darcy
Connecticut Resources Recovery
Authority
Hartford, Connecticut
IV-D-53
P.J. Yaroschak
Department of the Navy
Washington, D.C.
IV-D-54
T.J. Richter
Minnesota Resource Recovery
Association
St. Paul, Minnesota
IV-D-55
M. Brinker
Greater Detroit Resource Recovery
Authority
Detroit, Michigan
IV-D-56
R.F. Anderson
Wheelabrator Technologies, Inc.
Washington, D.C.
2-6
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No. Commenter and Affiliation
IV-D-57
E.H. Seeger, Vedder, Price, Kaufman,
Kammholz & Day
Submitting on behalf of the Lead
Industries Association, Inc.
New York, New York
IV-D-58
G. Postier
Olmsted County Association of
Townships
Oronoco, Minnesota
IV-D-59
Mayor S. James
Newark, New Jersey
IV-D-60
P. Ortner-Mukavetz
Clean Air, Please!
Madison Heights, Michigan
IV-D-61
G.R. Elliot
Lafarge Corporation
Southfield, Michigan
IV-D-62
Mayor D. Flury
City of Dover
Dover, Minnesota
IV-D-63
T.R. Rylander
Town of Madison
Madison, Connecticut
IV-D-64
A. Ellison and F. Sullivan
Baron County Waste-To-Energy Facility
Almena, Wisconsin
IV-D-65
John van der Harst
Recycling Advocates of Middle
Tennessee
Nashville, Tennessee
IV-D-66
A.A. Mendonsa
Office of the City Manager, City of
Savannah
Savannah, Georgia
IV-D-67
J.S. Bilmes
Bristol Resource Recovery Facility
Operating Committee
Bristol, Connecticut
2-7
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No.
Commenter and Affiliation
IV-D-68
L.J. Liszewski
Eastman Kodak Company
Rochester, New York
IV-D-69
N. Stafki
Northern States Power Company
Minneapolis, Minnesota
IV-D-70
J.J. Gallagher
Pasco County
New Port Richey, Florida
IV-D-71
J.J. Poulton
Waste Energy Partners Limited
Partnership
Joppa, Maryland
IV-D-72
M.B. Gamble
Tacoma Public Utilities
Tacoma, Washington
IV-D-7 3
R. Methier
Georgia Department of Natural
Resources
Atlanta, Georgia
IV-D-7 4
J.S. Grumet
Northeast States for Coordinated Air
Use Management
Boston, Massachusetts
IV-D-7 5
F.R. Caponi
County Sanitation Districts of
Los Angeles County
Whittier, California
IV-D-76
G.W. Lancour
McDonnell Douglas Corporation
Saint Louis, Missouri
IV-D-77
(Facsimile of IV-D-61)a
G.R. Elliot
Lafarge Corporation
Southfield, Michigan
IV-D-78
M. Benoit
Cement Kiln Recycling Coalition
New York, New York
2-8
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No. Commenter and Affiliation
IV-D-79 S.E. Ellis
Cadence Environmental Inc.
Michigan City, Indiana
IV-D-8 0 C. Kamper
County of Olmsted
Rochester, Minnesota
IV-D-81 K.W. Rieke
(Replaced by IV-D-98)C Ogden Projects, Inc.
Fairfield, New Jersey
IV-D-82 D.L. Lockhart
Solid Waste Authority
West Palm Beach, Florida
IV-D-83^ R. Hodanbosi
State of Ohio Environmental Protection
Agency
Columbus, Ohio
IV-D-84 Pellet Fuels Institute
Edina, Minnesota
IV-D-85 Integrated Waste Service Association
Washington, D.C.
IV-D-8 6 H. Magwood
Bureau of Sanitation, City of Savannah
Savannah, Georgia
IV-D-87 W.R. Darcy
Connecticut Resources Recovery
Authority
Hartford, Connecticut
IV-D-88 J.F. Eggen
United Power Association
Elk River, Minnesota
IV-D-89 S.P. Blakeslee
Intercounty Solid Waste Coordinating
Committee
Queesnbury, New York
IV-D-90 M.L. Mullins
Chemical Manufacturers Association
Washington, D.C.
2-9
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No. Commenter and Affiliation
IV-D-91 K.S. Goekjian
Town of Candia
Candia, New Hampshire
IV-D-92 Representative N. DeMarinis
House of Representatives, State of
Connecticut
Hartford, Connecticut
IV-D-93 C.D. Kellett
Safety-Kleen
Elgin, Illinois
IV-D-94 Integrated Waste Service Association
(Identical to IV-D-85)^ Washington, D.C.
IV-D-95 W. Wilson
Polk County Solid Waste Facilities
Fosston, Minnesota
IV-D-96 Mayor K.L. Schmoke
City of Baltimore
Baltimore, Maryland
IV-D-97 C. Campbell
Cement Kiln Recycling Coalition
Washington, D.C.
IV-D-98 M.H. Levin, Nixon, Hargrave,
Devans & Doyle
Washington, D.C.
Submitting corrected copies of comment
on behalf of Ogden Projects, Inc.,
Fairfield, New Jersey
IV-D-99 L.A. Johnson
Lee County Board of County
Commissioners
Fort Myers, Florida
IV-D-100 T. A. Sheridan
Town of Waterford
Waterford, Connecticut
IV-D-101 L.L. Bunn
South Carolina Department of Health
and Environmental Control
Columbia, South Carolina
2-10
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No. Commenter and Affiliation
IV-D-102
T.J. Maslany
U.S. EPA, Region III
Philadelphia, Pennsylvania
IV-D-103
T.M. Allen
New York State Department of
Environmental Conservation
Albany, New York
IV-D-104
L.W. Bitter
Davis County Solid Waste Management
and Energy Recovery Special Service
District
Layton, Utah
IV-D-105e
M.M. Round
Northeast States For Coordinated Air
Use Management
Boston, Massachusetts
IV-D-106
Representative M.K. McGratten
State of Connecticut House of
Representatives
Hartford, Connecticut
IV-D-107
J.S. McCann
The Lamphere Schools, Administration
Center
Madison Heights, Michigan
IV-D-108
W. O'Sullivan & K. Hart
Department of Environmental
Protection, State of New Jersey
Trenton, New Jersey
IV-D-109
D.R. Schregardus
State of Ohio Environmental Protection
Agency
Columbus, Ohio
IV-D-110
P.M. Tranchik
U.S. Army
Fort Dix, New Jersey
IV-D-111
A. Szurgot
American Ref-Fuel
Houston, Texas
2-11
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No.
Commenter and Affiliation
IV-D-112f
IV-D-113
(Identical
IV-D-114
IV-D-115
IV-D-116
IV-D-117
to IV-D-62)b
G.K. Crane
Ogden Martin Systems, Inc.
Fairfield, New Jersey
Mayor D. Flury
City of Dover
Dover, Minnesota
W. Wilson
Polk County Solid Waste Facilities
Fosston, Minnesota
R. Kell and V. Kell
Private Citizens
Madison Heights, Michigan
Representative B.R. Kolar
State of Connecticut
Hartford, Connecticut
Representative S. Mikutel
State of Connecticut
Hartford, Connecticut
IV-D-118
IV-D-119
(Facsimile
IV-D-120
IV-D-121
IV-D-122
of IV-D-116)a
H.S. Cole & Associates, Inc.
Attachment to original comment,
IV-D-17
Washington, D.C.
Representative B. Kolar
Connecticut House of Representatives
Hartford, Connecticut
A.M. Jackson
Minnesota Pollution Control Agency
St. Paul, Minnesota
S.C. Brand
Thermogenics, Inc.
Albuquerque, New Mexico
Representative W.O. Lipinski
United States Congress submitting
with
M.W. Turlek
of Lyons Incinerator Opponent
Network Lyons, Illinois
2-12
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No.
Commenter and Affiliation
IV-D-123
(see IV-D-40)g
Mayor M. Krause
City of Oronoco
Oronoco, Minnesota
IV-D-124
(see IV-D-58)g
G. Postier
Olmsted County Association
Townships
Oronoco, Minnesota
of
IV-D-125
(see IV-D-80)g
C. Kamper
County of Olmsted
Rochester, Minnesota
IV-D-126
M.W. Turlek
Lyons Incinerator Opponent
Lyons, Illinois
Network
IV-D-127
Mayor M. Krause
City of Oronoco
Oronoco, Minnesota
IV-D-128
Mayor L. Gray
City of Stewartville
Stewartville, Minnesota
IV-D-129
Mayor D. Flury
City of Dover
Dover, Minnesota
IV-D-130
C. Kamper
County of Olmsted
Rochester, Minnesota
IV-D-131
Mayor W. Bussell
City of Eyota
Eyota, Minnesota
IV-D-132
Mayor C. Hazama
City of Rochester
Rochester, Minnesota
IV-D-133
D.L. Segel
SBA Associates
Elmhurst, Illinois
IV-D-134 M. A. Gagliardo
Northeast Maryland Waste Disposal
Authority
Baltimore, Maryland
2-13
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONTINUED)
Item No. Commenter and Affiliation
IV-D-135
G.S. Arslanian
International Recycling, Ltd.
Fairlawn, New Jersey
IV-D-136
G.K. Crane
Ogden Martin Systems, Inc.
Fairfield, New Jersey
IV-D-137
J.F. Eggen
United Power Association
Elk River, Minnesota
IV-D-138
Deleted from Docket A-90-45, comment
intended for another docket
IV-D-139
M.J. Wax
Institute of Clean Air Companies
Washington, DC
IV-D-140
J. Greenberg
Browning-Ferris Industries
Washington, DC
2-14
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TABLE 2-1. LIST OF COMMENTERS ON PROPOSED NEW SOURCE
PERFORMANCE STANDARDS AND EMISSION GUIDELINES
FOR MUNICIPAL WASTE COMBUSTORS (DOCKET A-90-45) (CONCLUDED)
Item No.
Commenter and Affiliation
IV-D-141
J. Eggen
United Power Association
Elkriver, MN
a Several commenters sent comments via facsimile and followed
up by mailing a copy. In those cases where the facsimile
and the mailed copy were assigned different docket item
numbers, all comment summaries and responses refer to the
docket item number of the mailed copy only.
b Two identical sets of comments were received from this
commenter and assigned different docket item numbers. All
comment summaries and responses refer only to the docket
item number of the first of the two comments.
c This commenter submitted a corrected version of their
original comments.
d This item was not summarized. It notified the Air Docket
that substantive comments were forthcoming, and those
comments were filed under IV-D-109.
e This item is an attachment to item IV-D-74 and is summarized
under that item number.
f This item is an earlier draft of data submitted as part of
item number IV-D-98.
9 This comment is identical in every respect to the one in
parentheses except that it is addressed to a different
person. All comment summaries and responses refer only to
the comment in parentheses.
2-15
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TABLE 2-2. LIST OF COMMENTERS ON PROPOSED WITHDRAWAL OF THE
1991 SUBPART Cb EMISSION GUIDELINES FOR MUNICIPAL WASTE
COMBUSTORS (DOCKET A-8 9-08)
Item No. Commenter and Affiliation
VI-B-01 J.S. Bilmes
(Identical to Bristol Resource Recovery Facility
A-90-45: IV-D-67)a Operating Committee
Bristol, Connecticut
VI-B-02 D.H.M. Holihan
City of St. Petersburg
St. Petersburg, Florida
VI-B-03 P.G. Sunderland
Department of Environmental Services,
Arlington County
Arlington, Virginia
VI-B-04 Mayor M.S. Savage and C. James
City of Tulsa
Tulsa, Oklahoma
VI-B-05 J.S. Hadfield
Southeastern Public Service Authority
of Virginia
Chesapeake, Virginia
VI-B-06 C. Lake
City of Dunedin
Dunedin, Florida
VI-B-07 D.R. Schregardus
State of Ohio Environmental Protection
Agency
Columbus, Ohio
VI-B-08 H. Lanier Hickman
The Solid Waste Association of North
America
Silver Spring, Maryland
VI-B-09 J. Thomas Cochran
The United States Conference of Mayors
Washington, D.C.
VI-B-10 M.A. Gagliardo
Northeast Maryland Waste Disposal
Authority
Baltimore, Maryland
2-16
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TABLE 2-2. LIST OF COMMENTERS ON PROPOSED WITHDRAWAL OF THE
1991 SUBPART Cb EMISSION GUIDELINES FOR MUNICIPAL WASTE
COMBUSTORS (DOCKET A-89-08) (CONCLUDED)
Item No.
Commenter and Affiliation
<
i—i
i
ts
i
i—1
i—1
L.W. Bitter
Davis County Solid Waste Management
and Energy Recovery Special Service
District
Layton, Utah
VI-B-12
M. Zannes
Integrated Waste Services Association
Washington, D.C.
VI-B-13
H. Stuart Broom, Verner, Liipfert,
Bernhard, McPherson, and Hand,
Washington, D.C.
Submitting on behalf of Pinellas
County, FL
VI-B-14
D.A. Len
Montenay International Corporation
Miami, FL
VI-B-15
G.A. Green
Oregon Dept. of Environmental Quality
Portland, OR
a Two identical sets of comments were received from this
commenter and were assigned to different dockets with
different docket item numbers. All comment summaries and
responses refer only to the docket item number in
docket A-90-45.
2-17
-------
In several cases, commenters supported their comments by
referencing comments submitted by other commenters. Rather
than list the supporter's docket item number each time the
supported docket item number is listed, those commenters that
are supported by others are as follows: One commenter
(IV-D-20) supported and incorporated by reference the comments
submitted by the Cement Kiln Recycling Coalition (IV-D-78).
Two commenters (IV-D-48, IV-D-50) supported the comments
submitted by the Chemical Manufacturers Association (IV-D-90).
One commenter (IV-D-56) supported the comments submitted by
the Integrated Waste Services Association (IWSA) (IV-D-85).
Four commenters (IV-D-64, IV-D-70, IV-D-87, IV-D-95) supported
the comments submitted by the U.S. Conference of Mayors and/or
its affiliate, the Municipal Waste Management Association
(MWMA) (IV-D-44). Two commenters (IV-D-64, IV-D-88) supported
the comments submitted by the Minnesota Resource Recovery
Association (IV-D-54). One commenter (VI-B-04) submitted
comments in support of comments submitted by the Solid Waste
Association of North America (VI-B-08), the IWSA (IV-D-85),
and the MWMA (IV-D-4 4).
2.2 ORGANIZATION OF COMMENT SUMMARIES
Chapters 3.0 through 12.0 present a summary of
significant comments and EPA responses. The comments are
grouped by subject areas, and the organization of topics is
similar to the organization of the proposal preamble for the
NSPS and emission guidelines.
Chapter 3.0 contains comments on the applicability of the
proposed NSPS and emission guidelines and comments on the
proposed emission limits for MWC organics, acid gases, metals,
particulate matter, and nitrogen oxides. These include
comments on selection of the maximum achievable control
technology (MACT) floor and MACT requirements for control of
MWC emissions, the selected size categories for MWC's, the
proposed emission limits, good combustion practice
2-18
-------
requirements, and the testing, monitoring, and reporting
provisions. Comments on the environmental, economic, and
other impacts of the standards are also included.
Chapter 4.0 summarizes comments on the proposed NSPS
siting analysis and materials separation plan requirements and
the associated compliance demonstration and reporting
provisions. The environmental, economic, and other impacts of
materials separation are also discussed. In addition,
chapter 4.0 contains more general comments on national
strategies to promote municipal solid waste recycling.
Chapter 5.0 summarizes comments on the proposed NSPS
standards for fugitive ash emissions including comments on
selection of the standards and test methods for visible
emissions. Chapter 6.0 includes other comments on
miscellaneous issues related to the NSPS.
Chapters 7.0 through 10.0 summarize comments on the
proposed emission guidelines for existing MWC plants. In many
instances, comments apply equally to new and existing MWC
plants regulated under the NSPS and emission guidelines. In
such cases, the comment is fully summarized and is responded
to under chapters 3.0 through 6.0 regarding the NSPS and only
briefly mentioned under chapters 7.0 through 10.0 regarding
the guidelines, referring the reader back to the NSPS section
where the response to the comment appears. Only those
comments and responses that pertain specifically to the
emission guidelines are fully summarized and responded to in
chapters 7.0 through 10.0.
Chapter 7.0 contains comments related to the guidelines
for MWC emissions and compliance schedules for existing MWC
units. Chapter 8.0 focuses on the Environmental Protection
Agency's proposition to require materials separation
provisions for the emission guidelines. Chapter 9.0
summarizes comments on the proposed emission limit for
2-19
-------
fugitive ash emissions; and chapter 10.0 includes
miscellaneous comments on topics related to the guidelines.
Chapters 11.0 and 12.0 address comments on two issues
related to the proposed guidelines. Chapter 11.0 summarizes
comments on the withdrawal of the 1991 Municipal Waste
Combustion Emission Guidelines (subpart Ca). Chapter 12.0
contains comments on Executive Order 12875.
2.3 LIST OF ACRONYMS AND ABBREVIATIONS FOR UNITS OF MEASURE
ACRONYMS
Act Clean Air Act
Administrator EPA Administrator
Agency EPA
APC air pollution control
APCD air pollution control device
APCS air pollution control system
ASME American Society of Mechanical Engineers
BACT best available control technology
BDT best demonstrated technology
BID background information document
CAAA Clean Air Act Amendments
Cd cadmium
CEM continuous emissions monitor
CEMS continuous emissions monitoring system(s)
CETRED Combustion Emissions Technical Resource
Document
CFR Code of Federal Regulations
CKRC Cement Kiln Recycling Coalition
CMA Chemical Manufacturers Association
CO carbon monoxide
CO2 carbon dioxide
COM continuous opacity monitor
COMS continuous opacity monitoring system(s)
DAS data acquisition system
DEP Department of Environmental Protection
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dioxins polychlorinated dibenzo-p-dioxins
DOE U.S. Department of Energy
DSI duct sorbent injection
EPA U.S. Environmental Protection Agency
ERC emission reduction credit
ESP electrostatic precipitator
EU European Union
FBC fluidized-bed combustor
FF fabric filter (baghouse)
FR Federal Register
furans polychlorinated dibenzofurans
GCP good combustion practice
HAP hazardous air pollutant
HC1 hydrogen chloride
Hg mercury
HWI hazardous waste incinerator
ICP-MS inductively coupled plasma mass spectroscopy
ITEQ international toxic equivalents
IWSA Intergrated Waste Services Association
LAER lowest achievable emission rate
MACT maximum available control technology
MB mass burn
MB/WW mass burn/waterwall combustor
MOD/EA modular/excess air combustor
MSW municipal solid waste
MWC municipal waste combustor
MWI medical waste incinerator
MWMA Municipal Waste Management Association
NAAQS national ambient air quality standard
NESCAUM Northeast States for Coordinated Air Use
Management
NESHAP national emission standards for hazardous air
pollutants
NLC National League of Cities
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NEPA National Environmental Policy Act
N0X nitrogen oxides
NRDC Natural Resources Defense Council
NSPS new source performance standards
NSR new source review
O2 oxygen
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
OPI Ogden Projects, Inc.
OSHA Occupational Safety and Health Administration
Pb lead
PCB's polychlorinated biphenyls
PCDD/PCDF polychlorinated dibenzo-p-dioxins and
polychlorinated dibenzofurans
PIC products of incomplete combustion
PM particulate matter
PQL practical quantitation Limit
PSD prevention of significant deterioration
PTC power test code (see ASME)
PVC polyvinyl chloride
QA quality assurance
QRO Qualification of Resource Recovery Facility
Operators
RAC reference air concentration
RACT reasonably available control technology
RCRA Resource Conservation and Recovery Act
RDF refuse-derived fuel
REF refractory
RRF resource recovery facility
RSD risk specific dose
SARA Superfund Amendments and Reauthorization Act
SCA specific collection area (Re: ESP's)
SCR selective catalytic reduction
SD spray dryer
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SIP State implementation plan
SNCR selective noncatalytic reduction
SO2 sulfur dioxide
S0X sulfur oxides
STAPPA/ALAPCO State and Territorial Air Pollution Program
Administrators and the Association of Local
Air Pollution Control Officials
SWANA Solid Waste Association of North America
SWPD Solid Waste Processing Division (part of ASME)
TEF toxic equivalency factor
TEQ toxic equivalent (e.g., 2,3,7,8-
tetrachlorinated dibenzo-p-dioxin toxic
equivalent)
TSP total suspended particulates
USC United States Code
VOC volatile organic compounds
WTE waste-to-energy
ABBREVIATIONS FOR TTNTTS OF MEASURE
Btu = British thermal unit
°C = degrees Celsius
dscf = dry standard cubic foot (@ 14.7 psia, 68 °F)
dscm = dry standard cubic meter (@ 14 psia, 68 °F)
°F = degrees Fahrenheit
gr = grains
kg = kilogram (10+3 grams)
lb = pound
m^ = cubic meter
mg = milligrams (10~3 grams)
Mg = megagram (10+6 grams)
MMBtu = million Btu
ng = nanogram (lO-^ grams)
Nm^ = normal cubic meter (@ 14.7 psia, 32 °F)
ppm = parts per million
ppmv = parts per million by volume
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psia
tons/day
tons/yr
|lg
yr
= pounds per square
= tons per day
= tons per year
= microgram (10~6 grams
= year
inch, absolute
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3.0 NEW SOURCE PERFORMANCE STANDARDS -
MUNICIPAL WASTE COMBUSTOR EMISSIONS
3.1 SELECTION OF SOURCE CATEGORY
Comment: One commenter (IV-D-35) contended that the
proposed NSPS and guidelines should not apply to "any mixture"
of industrial waste and MSW, as stated in the preambles as
follows: "Any mixtures of industrial process/manufacturing
discards with nonprocess industrial waste or with household,
commercial, or institutional waste is considered to be MSW."
The commenter pointed out that under this requirement, an
industrial boiler firing 1 percent MSW would be subject to the
proposed NSPS and guidelines. The commenter argued that the
proposed "any mixture" requirement (hereafter referred to as
the "mixture rule") would subject almost all industrial waste
to the proposed NSPS and guidelines, and such an action is
unsubstantiated and runs counter to the goals of the Act. The
commenter expressed surprise at the "mixture rule," since the
preambles do not offer any substantive discussion as to why
the "mixture rule" is necessary and passes the requirement off
as a "minor editing" change in the definition of MSW (see
59 FR 48212) . The commenter pointed out the EPA's own words
in the 1991 promulgated NSPS (56 FR 5495) that industrial
waste and MSW should not be subject to the same standard:
"industrial process wastes are excluded from the definition of
MSW. These wastes are usually different in character than MSW
and were not intended to be covered under this standard." The
commenter also cited language from the Act that commands the
EPA to develop standards that are specifically applicable to
industrial and commercial waste.
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The commenter argued that the "mixture rule" runs counter
to the goals of RCRA and State recycling laws. The commenter
explained that the proposed "mixture rule" would discourage
the use of industry source-separated materials, such as paper,
plastics, and wood, that cannot be recycled back into
products, as clean fuels. The commenter urged the EPA to drop
the "mixture rule" and rely, instead, on the 30-percent
cofiring definition of MSW.
Response: In the proposed standards, it was not the
EPA's intent that industrial boilers, MWI's, and other
incinerators (or boilers) combusting small amounts of MSW be
subject to the proposal. It was also not the EPA's intent to
redefine industrial waste and other non-MSW streams as MSW.
The EPA had attempted to explain its intentions by example and
by definition. The comments indicate that the EPA was not
successful in its efforts.
At proposal, it was the EPA's intent that combustors
firing principally MSW and located at plants with greater than
35 Mg/day aggregate combustion capacity be covered by the
proposal. This would mean an MWC larger than 35 Mg/day
combustion capacity and firing 100 percent MSW would be
covered by the proposal and would not become exempt from the
MWC regulation by simply firing a small amount of industrial
waste or other non-MSW waste stream. For example, a combustor
firing 100 percent MSW at a rate of 400 Mg/day would be
covered by the MWC regulation. Coverage would not change if
the owners decided to fire an additional 4 Mg/day industrial
waste with the MSW stream.
The concept that the EPA was attempting to explain was
that an MWC does not become a non-MWC simply by firing a small
amount of non-MSW. The proposal was interpreted by some to
mean that an industrial incinerator (or boiler) principally
firing industrial waste (or other non-MSW) would become
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subject to the MWC regulation if it fired any amount of MSW.
This was not the EPA's intent.
To clarify this point, the definition of MSW in the final
NSPS and guidelines has been revised and does not include any
reference to mixtures of industrial waste, medical waste, or
non-MSW. Additionally, a provision has been added that any
combustor, incinerator, or boiler firing less than 10 Mg/day
MSW is not covered by the regulations. This provision
supplements the 30 percent cofiring provision.
The 10 Mg/day criteria was selected after considering
that a cofired combustor of 35 Mg/day capacity (lower size
cutoff for the NSPS and guidelines) could fire up to
30 percent MSW (10 Mg/day) before being considered an MWC.
The owner or operator of a combustor, incinerator, or
boiler can elect to exercise either the 30 percent cofiring
exemption or the 10 Mg/day MSW de minimis cutoff exemption.
The 10 Mg/day cutoff exemption is more appropriate for units
firing small amounts of MSW.
Comment: Three commenters (IV-D-18, IV-D-35, IV-D-103)
argued that mixtures of medical waste and MSW should not be
regulated under the NSPS and guidelines, as stated in the NSPS
and guidelines preambles: "any mixtures of medical waste with
nonmedical hospital waste or with household, commercial, or
institutional waste is considered to be MSW." One commenter
(IV-D-35) argued that there is no scientific or public policy
basis for this decision. Another commenter (IV-D-18) stated
that according to the proposed NSPS and guidelines, medical
wastes are not considered to be MSW. One commenter (IV-D-74)
expressed support for the EPA's decision to exclude MSW and
MWI's from the guidelines by choosing the 35 Mg/day lower size
cutoff for applicability. This commenter noted that MWI's
would be regulated by a separate rulemaking.
Three commenters (IV-D-18, IV-D-35, IV-D-103) indicated
that the upcoming MWI rule should be considered in regulating
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medical waste mixtures. One commenter (IV-D-35) argued that
until regulations for MWI's are finalized, there is no basis
for regulating mixtures of MSW and medical waste, since
medical waste is substantially different from MSW and may
require different approaches in regulating emissions. One
commenter (IV-D-18) supported an approach that would require
that mixtures of medical waste and municipal waste be handled
with the same care and concern with which a segregated medical
waste stream would be handled and suggested regulating
mixtures under the MWI rule. Two commenters (IV-D-35,
IV-D-103) suggested that the EPA take a different approach in
regulating mixtures of medical waste and MSW by requiring that
sources combusting a combination of medical waste and MSW meet
the more stringent of the standards that will be promulgated
under section 111 of the Act. One commenter (IV-D-18)
expressed recognition of the fact that there may be
complications even in this suggested approach, such as a need
for unique handling problems presented by medical waste, that
may require a separate regulation. The commenter concluded,
however, that their suggested approach would be more logically
consistent with how the regulation of different source
categories is developed under section 111 of the Act.
One commenter (IV-D-35) further argued that by defining
medical waste mixed with MSW as MSW, the EPA is contradicting,
and therefore undermining, existing State regulations that
define medical waste mixed with MSW as medical waste, subject
to more stringent management standards. The commenter
explained that MWI's are currently regulated by various
conflicting State and Federal regulations and that in the
absence of coordinated Federal regulations, States have
adopted medical waste regulations that define medical waste
and set standards for medical waste treatment technologies.
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The commenter (IV-D-35) urged the EPA to clearly state in
the final rule the scope of the final rule as it relates to
MWI's and to the forthcoming MWI regulations.
Response: Separate NSPS and emission guidelines are
currently being developed under section 129 of the Act for
MWI's, and it was not the EPA's intent in the proposed MWC
NSPS and guidelines that MWI's be covered under the MWC rule
unless the combustion capacity is greater than 35 Mg/day and
more than 30 percent of the waste stream (on a unit basis) is
MSW. As indicated by the commenters, the proposed definition
of MSW was interpreted to mean that MWI's firing even very
small quantities of MSW would be subject to the MWC rule.
Because this was not the EPA's intent, the definition of MSW
in the final standards and guidelines was revised to exclude
reference to segregated medical waste streams. Refer to the
EPA's response to another comment in this section for further
discussion of this revision to the definition of MSW.
Additionally, a provision was added to the definition of MWC
to exclude from the definition any plant combusting a very
small quantity of MSW (i.e., a plant with a federally
enforceable permit limiting the plant to combusting less than
10 Mg/day of MSW).
As discussed elsewhere in this section, the 10 Mg/day
cutoff is based on the exemption for cofired combustors. Any
plant with total plant capacity greater than 35 Mg/day that
combusts less than 10 Mg/day of MSW as part of its waste
stream would have been considered under the proposed NSPS and
guidelines a cofired combustor and would only have been
subject to reporting and recordkeeping provisions for cofired
combustors. The 10 Mg/day exemption will simplify this
intended exemption for cofired combustors like MWI's that fire
only very small quantities of MSW and reduce the reporting and
recordkeeping burden. Under the final NSPS and guidelines,
such plants are not to be considered cofired combustors or
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MWC's and are not subject to any provisions of the final rules
except an initial report providing a copy of the permit
limiting the amount of MSW that may be combusted by the plant.
The EPA expects that only a few incinerators will be
covered under both the final MWC regulations and the future
MWI regulations. Few MWI's are larger than 35 Mg/day plant
capacity, which is the lower size cutoff for applicability to
the MWC standards. This lower size threshold was selected by
the EPA after reviewing the population distributions of MWI's
and MWC's. The MWI population includes more than
3,000 combustors with a single combustion unit per facility
and an average size of less than 3 Mg/day combustion capacity.
Since the EPA has added the provision to the final MWC NSPS
and guidelines that excludes from the definition of MWC any
plants combusting less than 10 Mg/day of MSW, most MWI's that
fire segregated medical waste in combination with general
hospital waste (MSW) will not be covered by the MWC rule.
Those few large incinerators (greater than 35 Mg/day capacity)
that cofire medical waste and MSW and where MSW is more than
30 percent of the input (and more than 10 Mg/day) will be
covered by the final MWC regulations. Since both regulations
are being drafted under section 129 authority and both address
the same pollutants, the dual coverage simply results in the
incinerator complying with the most restrictive regulation.
Comment: Four commenters (IV-D-18, IV-D-35, IV-D-85,
IV-D-98) contended that the proposed definition of "MSW" for
the NSPS and guidelines should be revised and clarified
because they believe the definition of MSW is either unclear
relative to segregated wastes or inconsistent with the
proposed preamble language and with section 129 of the Act.
The commenters indicated that the regulations, as drafted,
will unnecessarily restrict MWC's from burning certain types
of wastes from industrial manufacturing plants.
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One commenter (IV-D-85) argued that nonsegregated
industrial process waste should be included in the definition
of MSW. Two commenters (IV-D-85, IV-D-98) indicated that the
proposed definition of MSW, by excluding nonsegregated
industrial process waste and nonhazardous industrial discards,
will preclude these wastes from being combusted by MWC's. One
of the commenters (IV-D-98) stated that some States have used
the EPA's MSW definition to limit the scope of materials an
MWC can combust under its operating permit. The commenter
argued that Congress had intended that the definition of MSW
apply solely for the purposes of sections 129 and 306 of the
Act, such that the EPA must specifically state in the final
rule that the definition applies solely for the purposes of
sections 129 and 306 of the Act.
Three commenters (IV-D-18, IV-D-35, IV-D-85) pointed out
an inconsistency between the preamble and regulatory text of
the NSPS regarding the definition of MSW. The commenters
cited the preamble to the NSPS, which states that "segregated"
industrial process/manufacturing discards are not MSW, but
"any mixture or industrial process/manufacturing discards with
nonprocess industrial waste or with household, commercial, or
institutional waste is considered MSW." One commenter
(IV-D-35) indicated that the rule itself does not mention
industrial waste in its definition of MSW, but does mention
medical waste. Commenter IV-D-85 requested that the EPA
specify in § 60.51b that a mixture of industrial process waste
and MSW is MSW.
Response: The definition of MSW is intended to specify
which types of waste trigger a combustion facility to be
covered under the MWC rule. The definition of MSW does not
define, as the commenters claim, limits to the types of waste
than an MWC can combust. Nowhere is it stated in the rule
that there is any limit on the type of waste an MWC can
combust. In fact, the definition of "cofired combustor"
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specifically states that a unit combusting more than
30 percent MSW is an MWC. An MWC is not prohibited under this
rule from combusting non-MSW items such as railroad ties,
telephone poles, or industrial manufacturing wastes.
The definitions of MWC and MSW under subparts Eb and Cb
are defined only for the purpose of these subparts. It is not
necessary to specify this intention in the subparts because it
is always the case that a term is defined within a subpart for
the limited purposes of the specific subpart. If a State
wishes to borrow the definition of MWC or MSW for the purpose
of their authorized RCRA program, the State has that
prerogative; however, a State is not required to utilize the
definition of MWC and MSW under subparts Eb and Cb for the
purpose of their authorized RCRA program.
Industrial/commercial manufacturing waste and medical
waste were not included in the definition of MSW because the
EPA is developing separate regulations covering the combustion
of these materials under section 129 of the Act. Therefore,
the definition of MSW in the final NSPS and guidelines will
not refer to segregated medical waste or segregated industrial
waste. However, the definition of MSW has been revised to
clarify that MSW includes nonmedical waste discarded from
hospitals (office paper, cafeteria waste, etc.). The proposed
and promulgated definitions of MSW both specify that
nonprocess wastes discarded by industrial facilities are
included in the definition of MSW.
Comment: One commenter (IV-D-26) argued that the MWC
rule should not apply to the pyrolysis of recycled plastics.
The commenter explained that recovering plastics from MSW for
use in the production of synthetic materials for clothing,
monomers for plastics, lubricating oils, etc., is materials
recovery since it involves recovering a liquid hydrocarbon
product from solid waste rather than producing it from
petroleum or other higher-value petrochemicals. The commenter
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argued that excluding plastics recycling from coverage under
the MWC rule would be consistent with: (1) The current
exemption in the MWC rule for metals recovery facilities, and
(2) the RCRA, which defines "recovered material" as waste
materials that have been recovered from solid waste. The
commenter provided data indicating that 70 to 80 percent of
the material recovered from MSW would be converted into
plastic components and sold as liquid product (feedstock) to
companies that use it to manufacture new petroleum-based
products. The commenter indicated that 5 to 10 percent of the
recycled plastic input into the plastic recycling process is
sold as carbon for use in the production of miscellaneous
products (e.g., activated carbon and rubber goods). The
information provided by the commenter thus indicated that
10 to 25 percent of the plastic recovered from MSW for input
into the process is noncondensible vapor that is used
(combusted) within the recycling process to generate process
heat.
Response: The commenter is correct that the EPA's
current solid waste disposal policy encourages materials
recovery. As stated in the EPA report "The Solid Waste
Dilemma: An Agenda for Action" (EPA/530-SW-88-052), on a
national basis, the preferred hierarchy of waste management is
(1) Source reduction, (2) recycling of materials, and
(3) incineration and landfilling. In consideration of this
policy and the comment, the EPA concluded that, under certain
conditions, a plant that recycles plastics and rubber should
not be covered under the MWC NSPS or emission guidelines. A
plastics/rubber recycling unit has been defined in the final
rule as an integrated processing unit where plastics, rubber,
and/or rubber tires are the only feed materials (incidental
contaminants may be included in the feed materials) and they
are processed into a chemical plant feedstock or petroleum
refinery feedstock, where the feedstock is marketed to and
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used by a chemical plant or petroleum refinery as input
feedstock. The combined weight of the chemical plant
feedstock and petroleum refinery feedstock produced by the
plastics/rubber recycling unit on a calendar quarter basis
shall be more than 70 percent of the combined weight of the
plastics, rubber, and/or rubber tires processed by the
plastics/rubber processing unit on a calendar quarter basis.
The plastics, rubber, or rubber tire fed to the plastics/
rubber recycling unit may originate from the separation or
diversion of plastics, rubber, or rubber tires from MSW or
industrial solid waste, and may include manufacturing scraps,
trimmings, and off-specification plastics, rubber, and rubber
tire discards. The plastics, rubber, or rubber tires fed to
the plastics/rubber recycling unit may contain incidental
contaminants (e.g., paper labels on plastic bottles, metal
ring on plastic bottle caps, etc.). Pyrolysis/combustion
units that are an integrated part of a plastics/rubber
recycling unit (as defined above) are not subject to the MWC
NSPS or emission guidelines if the owner or operator of the
plastics/rubber recycling unit keeps records of (1) the weight
of plastics, rubber, and/or rubber tires processed on a
calendar quarter basis, (2) the weight of chemical plant
feedstocks and petroleum refinery feedstocks produced and
marketed on a calendar quarter basis, and (3) the name and
address of the purchaser of the feedstocks. The combustion of
gasoline, diesel fuel, jet fuel, fuel oils, residual oil,
refinery gas, petroleum coke, liquified petroleum gas,
propane, or butane produced by chemical plants or petroleum
refineries that use feedstocks produced by plastics/rubber
recycling units are not subject to the MWC NSPS and
guidelines.
Comment: One commenter (IV-D-35) urged the EPA to modify
the definition of "MSW" and "RDF" in order to exclude fuel
products derived from certain source-separated portions of the
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MSW stream from being subject to the proposed NSPS and
guidelines. The commenter argued that materials separated are
"inherently cleaner materials and do not suffer from the
quality control constraints that mixed MSW does." The
commenter indicated that including these separated materials
in the definition of MSW would discourage the use by
industrial boilers or furnaces of source-separated materials,
such as paper, plastics, and wood that cannot be recycled back
into goods as clean fuels. The commenter argued that this
result would run counter to the goals of RCRA and State
recycling laws. The commenter pointed out that two-thirds of
the States have recycling laws that require them to reach a
50-percent recycling rate or 50-percent landfill diversion
rate within the next several years. The commenter stated that
energy recovery will be a key management technique for
achieving these aggressive rates and will be an important
source of swing demand when materials recycling markets are
incapable of generating demand.
Another commenter (IV-D-33) urged the EPA to expand the
category of fuels, including waste oil and tires, that are not
subject to the proposed NSPS and guidelines by including solid
waste-derived materials that provide energy value and that
have been shown to have a net environmental benefit when
compared to fossil fuel combustion alone. The commenter
specifically discussed the qualities of pelletized paper fuel
that would make this fuel a candidate for consideration. The
commenter explained that pelletized paper fuel is made from
paper that has been recycled but which cannot be used to make
new paper and paperboard products by the pulp and paper
industry. The commenter continued that this fuel can provide
a high heating-value material (7,500 to 8,000 Btu), which,
when cofired with coal, results in lower emissions of SO2,
HC1, and chlorine than combustion of coal alone. The
commenter argued that there is no compelling policy or
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scientific reason not to grant single-component, MSW-derived
materials used as fuels, such as pelletized paper, the same
status as tires and waste oil. The commenter warned that
failure to provide such an exemption could stifle an
environmentally beneficial and energy-saving industry practice
that is just now emerging.
Response: Industrial manufacturing waste is not MSW. A
separate rulemaking is under development to address industrial
waste. If the separated wastepaper and plastics mentioned by
commenter IV-D-35 are discards from residential,
commercial/retail, or institutional facilities as specified in
the definition of MSW, then they are considered to be MSW. A
combustor firing these separated materials would be covered by
the NSPS and guidelines unless it (1) Qualifies as a cofired
combustor (less than 30 percent of the waste stream is MSW),
(2) fires less than 10 Mg/day of MSW, or (3) is a plastics/
rubber recycling unit (refer to discussion earlier in this
section). Mixed wastepaper and RDF are considered to be MSW.
If the pelletized paper fuel identified by commenter
IV-D-33 is produced from wastepaper discarded from
residential, commercial/retail, or institutional facilities as
specified in the definition of MSW, then the pelletized paper
fuel is a form of RDF and is considered to be MSW.
Section 129 specifically includes RDF in the definition of
MSW. A combustor firing RDF made from MSW would be covered by
the NSPS and guidelines unless it (1) Qualifies as a cofired
combustor (less than 30 percent of the waste stream is RDF),
or (2) fires less than 10 Mg/day of RDF.
Comment: One commenter (IV-D-53) contended that nonpower
production plants (e.g., steam generation plants) that combust
a single-item waste stream of used oil should not be subject
to the proposed NSPS and guidelines. The commenter pointed
out that the proposed rules specify that electric power
generation facilities that combust a single-item waste stream
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of used oil are not subject to the proposed standards. The
commenter contended that MWC plants that burn used oil for
non-electric power production purposes (steam or process heat)
should not fall within the scope of the proposed rules for the
following reasons: (1) Such nonpower production plants are
not "solid waste incineration units" as defined in
paragraph (g)(1)(B) of section 129 of the Act, (2) combustion
of oil is already covered by RCRA, section 6901, and
(3) oil-fired boilers are very different from MWC's and were
not considered in the determination of MWC MACT. The
commenter discussed these three reasons in detail.
Response: Used oil is a liquid waste and not a solid
waste, so used oil is not considered to be MSW. The
definition of MSW has been revised under the NSPS and
guidelines to specify that used oil does not fall under the
definition of MSW. Combustion units that burn only used oil
are not covered by the MWC NSPS and guidelines. Furthermore,
any combustion unit firing a waste stream of used oil with
MSW, in which MSW is less than 30 percent of the waste stream,
would be considered a "cofired combustor" under the final NSPS
and guidelines. Also, any combustion unit firing a waste
stream of used oil with MSW, in which MSW makes up less than
10 Mg/day of the waste stream is exempt from the NSPS and
guidelines. Cofired combustors and combustors firing less
than 10 Mg/day of MSW are not subject to the NSPS and
guidelines, as long as they submit a notification of their
exemption and keep records of the daily amounts of MSW fired.
Comment: One commenter (IV-D-20) suggested that the EPA
should revise the definition of "municipal-type solid waste"
for the NSPS and guidelines to exclude renovation wastes since
construction and demolition wastes are already excluded and,
although renovation is a slightly different process, personnel
involved in renovation activities would be doing the same
things as construction or demolition workers.
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Response: The proposed definition of MSW did not
specifically mention renovation wastes because it was assumed
by the EPA that renovation wastes are a subset of
construction/demolition wastes, which are already excluded
from the definition of MSW. However, to clarify this point,
the term "renovation waste" was added to the list of wastes
specifically excluded from the definition of MSW for the
purpose of the NSPS and guidelines. Examples of construction/
demolition/renovation wastes are wastes from demolished
buildings, railroad ties, and telephone poles.
Comment: One commenter (IV-D-03) contended that the
definition of "MSW" creates inconsistencies in the application
of the NSPS and guidelines to industrial boilers burning waste
materials. The commenter provided the following two examples:
(1) Boilers burning tires that are manufacturing rejects or
scrap paper recovered from the manufacturing process would not
be subject to the regulation, whereas identical plants burning
discarded tires or paper discards segregated for recycling
from commercial, residential, and institutional establishments
would be subject to the regulation, and (2) industrial boilers
that burn tires that are manufacturing rejects and process
scraps are likely to burn these same materials as commercial,
residential, and institutional discards.
Response: The definition of MSW does not result in
inconsistencies in the application of the NSPS and guidelines
to industrial boilers burning waste materials. Under the
final NSPS and guidelines, industrial boilers and other
combustors that fire more than 30 percent MSW will be subject
to the MWC NSPS. The MWC NSPS and guidelines are intended to
regulate the combustion of MSW, not industrial process wastes.
If the materials fired by the boiler are similar in content to
MSW (e.g., paper) but are not MSW (e.g., scrap paper recovered
from the manufacturing process), then the boiler will not be
covered under the final MWC NSPS unless those materials are
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part of a waste stream including more than 30 percent MSW.
However, the EPA is currently developing a regulation for
industrial waste combustors under section 129 of the Act.
Therefore, combustion of materials that are MSW (e.g., paper)
and similar materials that are industrial process wastes
(e.g., paper and scrap paper recovered from the manufacturing
process) will ultimately both be considered for regulation
under section 129 of the Act.
Comment: One commenter (IV-D-03) contended that
industrial boilers producing process steam or electricity and
fueled by a segregated single-item waste stream or from
segregated waste streams comprised of materials with known
chemical composition should not be subject to the MWC NSPS and
guidelines that were designed to apply to incinerators burning
mixed MSW. The commenter argued that if wastes are segregated
to eliminate the inclusion of metals, then the facility should
not be required to conduct annual metals testing. Another
commenter (IV-D-101) suggested that tree trimmings, yard
wastes, and clean unfinished lumber be added to the list of
single-item waste streams for these power production plants.
Response: Section 129 of the Act specifies the exemption
from the MWC rule for waste-fuel power generating facilities.
The exemption as specified under paragraph (g)(1) of
section 129 reads as follows:
...The term "solid waste incineration unit" does not
include ...qualifying small power production
facilities, as defined in section 3(17)(C) of the
Federal Power Act (16 U.S.C. 769(17)(C)), or
qualifying cogeneration facilities, as defined in
section 3(18)(B) of the Federal Power Act
(16 U.S.C. 796(18) (B), which burn homogenous waste
(such as units which burn tires or used oil, but not
including refuse-derived fuel) for the production of
electric energy or in the case of qualifying
cogeneration facilities which burn homogeneous waste
for the production of electric energy and steam or
forms of useful energy (such as heat) which are used
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for industrial, commercial, heating or cooling
purposes . . .
This section 129 wording has been incorporated into the final
MWC NSPS and guidelines under § 60.50b of subpart Eb to
specify the exemption for waste-fuel power generating
facilities required by section 129, replacing § 60.50b(d) and
the definition of "waste-fuel power generating facility" under
§ 60.51b. These changes will assure consistency with
section 129 of the Act.
Additionally, in the final MWC NSPS and guidelines "clean
wood" is not included in the definition of MSW. This
exemption was added to the final MWC rules for two reasons.
First, studies of dioxin/furan emissions from wood-fired
boilers show that the combustion of clean wood results in low
dioxin and mercury emissions. Based on studies by the
National Council of the Paper Industry for Air and Stream
Improvement, Inc. (NCASI) (January 1995), dioxin/furan
emissions for wood-fired boilers firing clean wood waste (i.e,
wood, wood chips, bark, and wood residue) were reported to
range on average from 7 to 19 ng/dscm (total mass). Based on
studies presented at the C.P. Tappi Environmental Conference
(1991) and by the New York State Energy Research and
Development Authority (NYSERDA) (November 1992), data for
wood-fired boilers show mercury emissions that range on
average from 0.0004 to 0.01 mg/dscm. Additionally, the EPA
expects that combustion of clean wood results in low emissions
of other pollutants such as lead and cadmium. Secondly, the
EPA is currently considering regulating air emissions from
wood-fired boilers under a separate rulemaking. Clean wood is
defined in the final NSPS and guidelines as wood or wood
products including clean untreated lumber (which is defined in
the proposed and final rule), tree stumps (whole and chipped),
and tree limbs (whole and chipped). Clean wood does not
include yard waste, which is considered to be MSW under the
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final rule. Yard waste is defined in the final NSPS and
guidelines as including grass, grass clippings, bushes, and
shrubs. Yard wastes are primarily generated by residential
areas and are typically considered part of the MSW stream. By
covering yard waste in the MWC rules, the EPA is encouraging
composting rather than the incineration of yard wastes.
Comment: One commenter (IV-D-135) contended that
nonpower production plants (e.g., steam generation plants)
that combust a single-item waste stream of tires should not be
subject to the proposed MWC NSPS and guidelines. The
commenter pointed out that the proposed rules specify that
only power generation plants that combust a single-item waste
stream of tires are not subject to the NSPS and guidelines.
The commenter contended that plants that burn tires for
nonpower production purposes should not fall within the scope
of the proposed rules for the following reasons: (1) The
emissions from a small-scale dedicated tire-fueled plant will
be identical whether the steam production is used to produce
electricity or process steam, (2) tire-fueled plants producing
process steam result in a reduction in the consumption and
importation of fossil fuel, (3) tire-fueled plants provide a
benefit to the environment by serving as a long-term solution
to the growing waste tire problem. Additionally, the
commenter indicated that whereas large dedicated tire-fueled
plants are best suited to produce electricity with their steam
production, the steam produced by smaller systems may be used
in a wider variety of applications, such as for process steam,
heat, air conditioning, drying grain, and actually using the
steam for a retreading operation.
The commenter described a new technology called the
"Recoverator" that combusts a single-item waste stream of used
tires, produces steam for various uses, and recovers
marketable byproducts from the tires, including unmelted
recoverable steel and zinc-rich dust. The commenter requested
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that the EPA consider this technology to be an "alternative
energy fueled boiler." The commenter provided an emissions
test report based on tests conducted in Italy that provide
data for PM, Pb, Cd, Hg, HC1, SO2, and "clororganics"
emissions from a Recoverator.
Response: The proposed MWC NSPS and guidelines have been
revised to include the wording from section 129 of the Act
that provides an exemption for certain plants that fire a
single-item waste stream of tires and produce energy. In
addition, the final NSPS and guidelines specifically exempt
combustion of single-item waste streams of tires. There are
no requirements for the production of electricity for this
exemption. This exemption is consistent with the 1991 MWC
NSPS and guidelines.
Comment: One commenter (IV-D-101) recommended allowing
the waste fuels covered under the exemption for waste-fuel
power generating plants in the NSPS and guidelines to be
combusted both singularly or in combination. The commenter
explained that they are aware of plants that have proposed to
their municipalities to burn tires and yard wastes in
combination, but did not pursue their proposals due to the MWC
regulations. The commenter argued that these proposals would
have benefitted both human health and the environment by
keeping the yard wastes from landfills.
Response: Section 129 of the Act provides an exemption
from the MWC rule for certain waste-fuel electric power
generating facilities and cogeneration facilities that combust
"homogeneous waste." Section 129 does not provide this
exemption for mixed waste streams; therefore, a single-item
waste stream of tires would be exempt from the final MWC NSPS
and guidelines, but a mixed waste stream of tires and yard
waste would be subject to the MWC NSPS and guidelines, because
both tires and yard waste are considered MSW under the final
rules. As mentioned above in this section, the EPA wants to
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encourage the composting of yard waste rather than the
incineration of yard waste.
Comment: Four commenters (IV-D-20, IV-D-50, IV-D-68,
IV-D-90) urged the EPA to clarify that combustion units
required to have a permit under RCRA are not subject to the
proposed NSPS and guidelines. Two of the commenters (IV-D-20,
IV-D-68) requested clarification that HWI's are not included
in the definition of "MWC" and not subject to the proposed
rules. Two of the commenters (IV-D-68, IV-D-90) also
requested clarification that metals recovery facilities are
not included in the definition of "MWC" and not subject to the
proposed NSPS and guidelines. Three of the commenters
(IV-D-20, IV-D-50, IV-D-90) indicated that section 129(g)(1)
of the Act supports this contention when it specifies that
solid waste incineration units "do[] not include incinerators
or other units required to have a permit under section 3005 of
the Solid Waste Disposal Act [or] materials recovery
facilities (including primary or secondary smelters) which
combust waste for the primary purpose of recovering metals . .
. ." Id § 7429(g)(1).
Response: Section 129 of the Act specifically exempts
from the MWC NSPS and guidelines incinerators required to have
a permit under section 3005 of the Solid Waste Disposal Act
and materials recovery facilities that combust waste for the
primary purpose of recovering metals. To be consistent with
section 129, the final guidelines and NSPS specifically exempt
these two categories of sources.
Comment: One commenter (IV-D-90) urged the EPA to
eliminate the requirement included in the definition of
"cofired combustor" that cofired units have federally
enforceable permits limiting their fuel feed stream. The
commenter pointed out that the statute [42 U.S.C.
§ 7429(g)(5)(B)] says nothing about permits, limits, or
enforceability. The commenter opposed requiring units to
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obtain permits for the sole purpose of confirming their
ineligibility for some requirement and asserted that it would
be sufficient to require only that it be enforceable, which
under current EPA practice does not require a permit. The
commenter recommended that the EPA's goal of ensuring some
sort of accountability could be adequately served by requiring
cofired combustors to notify the EPA of their status, and
potentially requiring them to report if they burn over
25 percent MSW in any reporting period.
Response: The commenter is incorrect that the EPA does
not require a permit to ensure enforceability. In most cases,
the only mechanism for ensuring enforceability of an operating
condition (e.g., of percent MSW in the fuel feed stream) is a
permit. Under the title V program, all MWC's are required to
have a permit. Therefore, the EPA is not introducing any new
requirements by requiring that a unit must have a permit that
includes a limit on the amount of MSW to be included in the
waste stream in order to qualify as a cofired combustor.
Comment: Three commenters (IV-D-20, IV-D-50, IV-D-90)
requested that the EPA change the averaging time basis for
determining whether or not a unit meets the definition of
"cofired combustor" from a 24-hour period to an annual period.
One of these commenters (IV-D-90) requested that, at a
minimum, the EPA adopt a monthly averaging period. Two of the
commenters (IV-D-20, IV-D-90) pointed out that section 129 of
the Act does not specify an averaging period for determining
the percentage of a unit's fuel that consists of MSW. These
commenters (IV-D-20, IV-D-90) argued that the EPA's proposed
averaging period of 24 hours is inappropriate for the
following reasons. One commenter (IV-D-20) argued that the
24-hour averaging period would result in units "sliding in and
out" of the rule's applicability on a daily basis. Both
commenters (IV-D-20, IV-D-90) argued that many units burn
different fuels "campaign-style," finishing an entire batch of
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one fuel before they start another. The commenters (IV-D-20,
IV-D-90) argued that the 24-hour averaging period would add a
substantial regulatory burden that serves no purpose, since
ultimately the same amount of MSW would be burned.
Response: After further investigation of the problems
associated with the daily averaging time included in the
proposed definition of a cofired combustor, the EPA decided to
lengthen the averaging time to a calendar quarter. Some
facilities that burn biomass materials that include yard waste
will have difficulty making a determination of cofired status
on a daily basis. Biomass material including yard waste
(which is MSW) and clean wood (which is not MSW) are often
collected together, intermixed, and stored onsite or offsite
for a period of time before being combusted. In such cases,
once the mixed material is combusted, it is difficult to
determine what percentage of the waste combusted daily was
yard waste. This change is consistent with current refuse
storage and recordkeeping procedures. This change will also
address the concerns raised above by the commenters regarding
plants "sliding in and out" of applicability to the MWC
standards or guidelines on a daily basis.
Comment: Four commenters (IV-D-21, IV-D-61, IV-D-78,
IV-D-97) contended that cement kilns should be excluded from
applicability under the proposed MWC NSPS and guidelines. The
commenters pointed out that the proposed NSPS and guidelines
broadly define "MWC" such that cement kilns recycling MSW as
fuel could be subject to the standards. Three of the
commenters (IV-D-78, IV-D-21, IV-D-97) contended that cement
kilns burning MSW cannot legally be covered under section 129
of the Act. The commenters discussed a variety of technical
and environmental policy reasons that the cement kiln industry
should not be covered under section 129.
One of the commenters (IV-D-97) contended that the EPA
should not plan to exclude cement kilns from the proposed NSPS
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and guidelines by assuming that the definition of cofired
combustor, with the 30-percent cutoff, will exclude cement
kilns. The commenter stated that although they are not aware
of any existing cement kilns that are including more than
30 percent MSW as part of their fuel, the percentage of MSW
combusted in cement kilns may be increased in the future.
Response: As the commenters pointed out, no existing
cement kilns combust more than 30 percent MSW as part of their
fuel. Thus, no existing cement kilns would be subject to the
final MWC guidelines. However, if any cement kilns combust
more than 30 percent MSW and more than 10 Mg/day of MSW, thus
qualifying as MWC's under the final NSPS in the future, they
would be considered MWC's under the final MWC NSPS and subject
to the MWC NSPS.
Comment: Two commenters (IV-D-26, IV-D-33) argued that
"pyrolysis" should not be covered under the proposed NSPS and
guidelines and should not be included in the definition of
"MWC." One commenter (IV-D-26) pointed out that in the
proposed regulatory text, the definition of "MWC" does not
refer to "pyrolysis," but that the preamble to the NSPS
proposes to include pyrolysis in this definition. The
commenter contended that section 129 of the Act did not give
the EPA the authority to regulate the pyrolysis of solid
waste. The commenter cited section 129 language defining
"solid waste incineration unit" as a unit that "combusts"
solid waste. The commenter stated that "pyrolysis" is an
improper characterization from both scientific and engineering
perspectives. Both commenters (IV-D-26, IV-D-33) explained
that pyrolysis, unlike "incineration" and "combustion," occurs
in the absence, rather than in the presence, of 02-
Response: At proposal, as indicated in the proposal
preamble, it was the EPA's intention to include pyrolysis
units in the definition of MWC. In the final NSPS, a
definition has been added to clarify that, for the purpose of
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this rulemaking, a "pyrolysis/combustion unit" is a unit that
first produces gases, liquids, or solids through the heating
of municipal solid waste; then, combusts the gases, liquids,
or solids produced; and, finally, vents the combustion
emissions to the atmosphere. Pyrolysis/combustion units that
are an integrated part of a plastics/rubber recycling unit are
not subject to the MWC NSPS and emission guidelines if the
owner or operator keeps certain records as specified in
§ 60.50b of the final NSPS. Refer to the discussion of
plastics/rubber recycling units elsewhere in this section.
3.2 SELECTION OF AFFECTED FACILITIES
Comment: Six commenters (IV-D-24, IV-D-51, IV-D-65,
IV-D-74, IV-D-91, IV-D-103) discussed the applicability of the
proposed NSPS and emission guidelines to small plants. Five
commenters (IV-D-24, IV-D-51, IV-D-65, IV-D-74, IV-D-103)
contended that the NSPS should apply to plants smaller than
35 Mg/day, and three of these commenters (IV-D-24, IV-D-51,
IV-D-65) contended that the emission guidelines should apply
to plants smaller than 35 Mg/day. Another commenter (IV-D-74)
suggested that only new plants smaller than 35 Mg/day, and not
existing plants smaller than 35 Mg/day, should be regulated,
as long as the majority of existing plants below 35 Mg/day are
MWI's that will be regulated in a separate rulemaking. Four
commenters (IV-D-24, IV-D-51, IV-D-65, IV-D-103) argued that
excusing plants smaller than 35 Mg/day from standards
encourages the construction and use of more poorly controlled
smaller plants and suggested that the development of these
smaller units should not be encouraged.
One commenter (IV-D-103) argued that all new MWC plants,
regardless of size, should be subject to the requirements
proposed for large MWC plants. The commenter continued that
without this restriction, new smaller uncontrolled
incinerators may replace larger existing MWC's, resulting in
an adverse impact on public health and the environment.
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Another commenter (IV-D-65) argued that smaller units:
(1) Result in larger costs per ton for the public to bear,
(2) are typically located in places where there is greater
flexibility in disposal options, and (3) are often located
nearer to food-crop producing activities. The commenter
claimed that humans typically ingest far more emitted
contaminants through food than through the air they breathe.
One commenter (IV-D-24) added that it has been shown that
smaller plants can be responsible for the worst ambient
impacts because - the commenter used New York City as an
example - apartment house incinerators are antiquated,
uncontrolled, badly operated, and emit at roof level. (For
further discussion on health effects, refer to section 6.1.)
The commenter advised that applying standards to these smaller
plants would encourage their wastes to be treated at larger
regional facilities that are controlled. The commenter cited
two examples of regulations that are causing smaller plants to
upgrade or close down: New Jersey's new Hg standard, which
does not exempt small plants; and New York City's law designed
to phase out 2,200 apartment incinerators and "small"
commercial and institutional incinerators. The commenter
recommended applying the NSPS to the smallest plants "right
away."
One commenter (IV-D-91) supported the fact that the
proposed NSPS and emission guidelines do not apply to MSW
combustors of less than 25 Mg/day capacity. The commenter
(IV-D-91) continued that the further tightening of controls on
combustors less than 25 Mg/day would force their shutdown due
to the controls being either technically impossible or
cost-prohibitive. The commenter added that the result of such
closures would be an increased usage of landfilling, which is
a less desirable alternative.
Response: Very small waste incinerators (i.e., with plant
capacity less than or equal to 35 Mg/day) are not being
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overlooked. They are currently being considered for rule
making under section 129 of the Act as part of a category of
combustors referred to as "other solid waste incinerators" (or
"OSWI"). The OSWI rule is scheduled for promulgation by the
year 2000. As noted in the preamble to the NSPS, those MWC*s
with capacity less than or equal to 35 Mg/day (i.e., those MWC
plants that will be considered under the OSWI rule rather than
the MWC rule) are estimated to comprise less than 1 percent of
the total nationwide combustion capacity of MWC's.
Additionally, as evidenced by the commenter's examples of NY
and NJ, State and local governments are free to establish
additional standards to address specific local air quality
concerns related to very small incinerators.
Regarding the comment that standards for small and large
MWC plants should be equivalent, the final standards for new
plants are equivalent for all pollutants except NOx•
In order to be consistent and to prevent overlaps in
future reporting requirements for MWC plants with capacity
less than or equal to 35 Mg/day, the initial reporting
requirement specified in § 60.50b(c) of the proposed NSPS for
MWC plants with combustion capacity greater than 25 Mg/day but
less than or equal to 35 Mg/day has been dropped in the final
rule.
3.3 MODIFICATION AND RECONSTRUCTION
Comment: One commenter (IV-D-18) said it is unclear in
the NSPS and emission guidelines what a "unit" is with regard
to modification or reconstruction. The commenter stated that
the EPA should clarify that a unit is the equipment used only
for combustion and pollution control since operation of only
that equipment can affect air emissions.
The commenter wanted to know how equipment common to more
than one unit would be evaluated with regard to modification
or reconstruction. The commenter provided an example of a
three-unit facility with two redundant lime slaking systems
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that feed all three units. The commenter asked whether
modifications to the lime slaking equipment would need to be
apportioned to each of the three units, or whether this
equipment is outside the definition of a "unit."
Response: With regard to modification or reconstruction,
the definition of MWC was expanded to define the components of
an MWC. An MWC unit subject to the standards includes, but is
not limited to, the fuel feed system, grate system, flue gas
system, bottom ash system, and the combustor water system.
Generally speaking then, the MWC unit starts at the MSW pit or
hopper and extends through (1) the combustor flue gas system,
which ends immediately following the heat recovery equipment,
or if there is no heat recovery equipment immediately
following the combustion chamber; (2) the combustor bottom ash
system, which ends at the truck loading station or similar ash
handling equipment that transfers ash to final disposal,
including all ash handling systems that are connected to the
bottom ash handling system; and (3) the combustor water
system, which starts at the feed water pump and ends at the
piping exiting the steam drum. The MWC unit does not include
air pollution control equipment, the stack, water treatment
equipment, or the turbine-generator set. Accordingly,
modification to equipment that falls outside the definition of
a combustion unit would not need to be apportioned to the
units when considering modification/reconstruction.
Comment: Two commenters (IV-D-18, IV-D-85) requested
that the proposed definition of "modified solid waste
incineration unit" be clarified. One commenter (IV-D-18)
argued that a unit should be considered to be a modified solid
waste incineration unit if a physical or operational change
increased pollutant emissions above the unit's permitted
emission limits, rather than above actual test results. The
commenter pointed out that the intent of the definition should
be revised to clarify this distinction. Otherwise, the
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commenter argued, facilities which have performed well in the
past will be penalized. The other commenter (IV-D-85) favored
the definitions as they stand in §§ 60.14 and 60.15 and stated
they are much more useful and practical.
Response: According to section 129 of the Act, any
"...physical change in or change in the method of operation of
the unit which increases the amount of any air pollutant
emitted by the unit for which standards have been established
under [section 129] or section 111" qualifies that unit as a
"modified solid waste incineration unit." The term "modified
solid waste incineration unit" was specified in the proposal
preambles for the NSPS and guidelines because section 129 of
the Act defines this term. That definition of "modified solid
waste incineration unit" specifies that a combustion unit is
considered to be "modified" under section 129 if one of the
following are true: (1) The cumulative costs of the
modifications of the MWC unit, over the life of the unit,
exceed 50 percent of the original cost of the construction and
installation of the unit (not including the cost of purchased
land), or (2) the modification is a physical change or change
in the method of operation of the MWC unit that increases
emissions from the unit of the regulated pollutants.
Emissions increases are determined at 100 percent physical
load and measured downstream of all APCD's. No consideration
is given for load restrictions based on permits or other
operational restrictions.
In the final rule, two new terms are defined to
incorporate the section 129 definition of "modified solid
waste incineration unit." The terms "reconstruction" and
"modification" (or "modified municipal waste combustor") are
defined to incorporate the section 129 definition of "modified
solid waste incineration." The definitions are almost
equivalent to the definitions of these two terms in § 60.14
and 60.15 of 40 CFR 60 subpart A.
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3.4 SELECTION OF THE MAXIMUM ACHIEVABLE CONTROL TECHNOLOGY
FLOOR FOR MUNICIPAL WASTE COMBUSTOR EMISSIONS
3.4.1 General Comments on MACT Floor Selection
Comment: Several commenters (IV-D-18, IV-D-20, IV-D-30,
IV-D-44, IV-D-75, IV-D-68, IV-D-85, IV-D-90, IV-D-98,
IV-D-104, VI-B-11) criticized EPA's approach of choosing the
best performing unit for new sources separately for each
pollutant when determining the MACT floor (this approach is
referred to by the commenters as "cherry picking"). The
commenters asserted that no single plant can achieve the best
control level for all regulated pollutants as determined by
the EPA. Three commenters (IV-D-18, IV-V-85, IV-D-98) said
that "cherry picking" inevitably results in a set of standards
unachievable by any unit. One commenter (IV-D-20) urged the
EPA to re-evaluate the data to assure that compliance is
achievable simultaneously for all pollutants.
Several commenters (IV-D-30, IV-D-68, IV-D-85, IV-D-90,
IV-D-98) pointed out that many pollutants are interrelated,
including the following: CO and N0X; PM, Cd, and Pb; SO2 and
HC1; PM and dioxins/furans; and CO and dioxins/furans. One
commenter (IV-D-30) said that an example is that higher
combustion temperatures reduce CO and dioxin/furan emissions
while increasing N0X emissions. Two commenters (IV-D-20,
IV-D-75) said that this approach does not account for site-
specific trade-offs in performance for multiple pollutants
from the same source. One commenter (IV-D-98) said an
analysis of data from large plants equipped with SD/FF
controls showed that performance of units at the same plant
(e.g., units 1 and 2 at the Warren MWC) vary widely, despite
the fact that they combust the same waste, use the same
control technologies, and are subject to the same operating
procedures. The commenter submitted a subset of their data
base, which is a revision to a PM and dioxin/furan data base
previously submitted by the commenter to the EPA.
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Response: The issue of interrelationship effects by
combined APCD systems was considered by the EPA. The MACT
floor emission levels for the NSPS at proposal required
SD/FF/SNCR. A substantial data base existed for SD/FF
technology, but a limited data base existed for combined
SD/FF/SNCR technologies. The proposed NSPS emission levels
(selection of MACT) would have required the additional use of
carbon injection technology (SD/FF/SNCR/carbon injection). At
the time of proposal no MWC existed that operated the combined
control system that would have been required to meet the
emission limits being proposed. Although no MWC units were
yet in operation with this new generation of control systems
(SD/FF/SNCR/carbon injection), the proposal was fully
consistent with section 111 and section 129 requirements.
Sections 111 and 129 require the EPA to develop and adopt
technology-forcing NSPS for new sources. The new MWC's
subject to the NSPS will be operated well into the next
century.
To address concerns about the effects of pollutant
interrelationships at proposal, the EPA was conservative in
its assessment of combined performance levels of the pollution
control systems. The proposed emission levels reflected this
conservative assessment.
Since proposal, 12 MWC units located at 5 MWC plants have
initiated operation of combined SD/FF/SNCR/carbon injection
control systems. Data were received from Falls/Bucks County,
PA; Onondaga, NY; Lee County, FL; Union County, NJ; and
Hennepin, NJ. All of the units at all of the plants are in
compliance with the proposed NSPS pollution emission levels.
These recent test results support the approach that the EPA
had taken at proposal in selecting the MACT floor and MACT
emission levels. For the final rule, these recent test
results support the selection of MACT floor emission levels
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and MACT emission limits that would require the use of carbon
inj ection.
Refer to section 3.11 of this BID for the EPA's response
to the legal issues raised by the commenters.
Comment: Several commenters (IV-D-18, IV-D-43, IV-D-44,
IV-D-49, IV-D-75, IV-D-85, IV-D-96) responded to the EPA's
request for comment on the basis of the MACT floor for new
sources. Two commenters (IV-D-43, IV-D-96) supported the
approach the EPA has taken in establishing MACT floors. Two
commenters (IV-D-44, IV-D-49) argued that the EPA's discretion
is limited by sections 112 and 129 of the Act to using only
actual performance data. Three commenters (IV-D-18, IV-D-75,
IV-D-85) supported the idea of using a permit basis to
establish the MACT floor for new plants. Two commenters
(IV-D-18, IV-D-85) objected to the idea of using a technology
or actual emissions data basis rather than a permit limit
basis for the MACT floor. The commenters reasoned that not
all technologies perform equally well in all applications.
One commenter (IV-D-49) said the EPA must use data
representing results achieved by the best performing similar
unit from plants which are determined to be best because they
have superior control technology, superior performance
maximized by GCP, and, ideally, materials separation. See
section 3.11 for a more complete summary of the legal issues
raised by the commenter.
Two commenters (IV-D-18, IV-D-85) objected to the idea of
using actual emissions data rather than permit limits as the
basis for determining the MACT floor. One commenter (IV-D-18)
contended that the EPA's 1989 data base is out of date and
would have to be substantially revised to serve as the basis
for the MACT floor. One commenter (IV-D-85) said the highest
emission data point over a period of years should be used.
One commenter (VI-D-18) suggested that all performance data
points, not just the most recent, should be averaged with a
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statistical confidence interval to be used as an emission data
base; alternatively, the highest data point out of a set of
data should be used.
Response: The EPA believes that a technology basis
should be used in determining the MACT floor and MACT for the
MWC NSPS, and has taken that approach. Refer to section 3.11
for a discussion of the legal issue. By reviewing performance
data, the EPA determined the technology representing MACT
(SD/FF/SNCR/carbon injection) and then defined the performance
capability of that technology combination. The performance
data base used to determine the capability of the technology
representing MACT has been updated with data more recent than
the 1989 data base. Data from plants that started operation
in 1990 or more recently were used because recent plants will
better represent new units. As suggested by two of the
commenters, the MACT floor levels for new plants represent the
upper bound of performance (i.e., the highest emission level)
consistently achievable by a specific APCD determined to be
MACT.
Comment: Several commenters (IV-D-28, IV-D-41, IV-D-43,
IV-D-44, IV-D-56, IV-D-67, IV-D-85, IV-D-95, IV-D-96, VI-B-02,
VI-B-05, VI-B-06) supported the EPA's decision not to rely on
European data, and one commenter (IV-D-24) argued that the EPA
should utilize European data.
Three of the commenters (IV-D-44, IV-D-56, IV-D-85)
pointed out that the EPA cannot make meaningful comparisons
with the proposed U.S. standards without a careful explanation
of the dissimilarities between the European country and the
U.S. Three of the above and two additional commenters
(IV-D-28, IV-D-96, VI-B-02, VI-B-05, VI-B-06) said they
supported EPA's "policy determination to reject blind
adherence" to the EU's guidelines.
Two commenters (IV-D-28, IV-D-44) contended that many
results reported by European plants appear to understate the
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actual performance because they lack the documentation and
quality assurance procedures that are required in the U.S. to
prove compliance. Two commenters (IV-D-44, IV-D-85) said that
EU member countries do not agree on how to properly measure
stack emissions for most of the EU pollutant emissions listed
in the guidelines. The commenters (IV-D-44, IV-D-85) reported
that the lack of a uniform, validated stack test method for
pollutants such as dioxin has caused the EU to initiate a
major study to compare various stack test methods. The two
commenters said this effort is in progress.
Three commenters (IV-D-44, IV-D-75, IV-D-85) also agreed
that EPA's proposed emission guidelines and NSPS are more
stringent than EU guidelines in most respects, for large
plants in particular. Four commenters (IV-D-28, IV-D-44,
IV-D-56, IV-D-85) noted that the European guidelines do not
address startup and shutdown excursions, while the U.S. plants
will be limited to 3 hours. One commenter (IV-D-56) said
plants in the Netherlands start up by igniting the MSW on the
grate without auxiliary fuel burners and are allowed to exceed
combustion-related standards, such as CO, for up to 10 to 12
hours during a cold startup.
Five commenters (IV-D-28, IV-D-43, IV-D-44, IV-D-56,
IV-D-85) mentioned differences between EU and U.S. policy with
respect to MWC's, in support of EPA's decision to not rely on
European data. Four of the commenters (IV-D-28, IV-D-43,
IV-D-44, IV-D-85) pointed out that the EU guidelines do not
have the force of law as in the U.S. Several commenters
(IV-D-43, IV-D-44, IV-D-56, IV-D-85) stated that there are
differences in national policy related to solid waste
management, differences in enforcement and testing to
determine noncompliance, and differences in the governmental
level which accepts financial responsibility. One commenter
(IV-D-56) provided several examples of the differences in the
reporting requirements and the German regulators' approach
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towards compliance. Two of the commenters (IV-D-44, IV-D-85)
noted that the Western European countries combust 30 to
60 percent of their waste because of national policies related
to the use of renewable fuels for energy and limiting the
disposal of organic wastes in landfills. The two commenters
stated that this policy guarantees a steady flow of household
waste to MWC's, whereas the solid waste market in the U.S. is
still highly competitive. These two commenters argued that
EPA's statement that "existing plants in the EU with
capacities greater than 144 Mg/day must meet the guidelines by
December 1, 1996" is misleading because the EU guideline
allows member countries to extend the effective compliance
date and that, in fact, the current compliance 1996 date is
actually an extension of the original 1993 compliance date.
One commenter (IV-D-85) said the changes in the latest draft
of the EU directive generally made the emission limit
proposals two to five times less stringent. The commenters
(IV-D-44, IV-D-85) asserted that the EU standards, which are
merely guidelines, are becoming less stringent because plants
have not demonstrated the ability to achieve the required
performance. The commenters also pointed out that, in Europe,
the cost of retrofits is borne almost entirely by the federal
government in contrast to the U.S. where the cost is borne
almost entirely by local governments.
One commenter (IV-D-24) stated that data from foreign
MWC's should be used in calculating MACT floors and the
standards for both new and existing sources. For new sources,
the commenter cited current EPA guidance under section 112 (j)
which "allows States to use foreign sources in calculating a
new source floor". The commenter presented data for new and
existing sources from both EPA's performance data base and
other sources, including European data. The commenter
presented revised MACT floors based on this data, using both
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foreign and domestic data for new sources and domestic data
only for existing sources.
Response: The EPA agrees that it is difficult to compare
European performance data to U.S. performance data due to
differences in test methods, QA standards, and reporting
methods. As noted in the proposal preamble and by the many
commenters above, there are differences between the EPA and EU
guidelines with regard to regulatory flexibility, compliance,
and test methods used to measure emissions. These factors
must be considered when comparing the respective emission
requirements. Also, as some of the commenters noted, there
are differences in national policy towards combustion of MSW
and funding of projects.
Although not precluded from using foreign data, the EPA
has chosen to rely on the reasonably large pool of performance
and permit data from domestic plants. For this reason, the
data from European plants submitted by commenter IV-D-24 were
not used in selecting the MACT floor emission levels, NSPS
emission limits, or emission guidelines emission limits. The
domestic pollutant emission data submitted by the commenter
were reviewed by the EPA; however, the additional data would
not change the MACT floor emission levels, NSPS emission
limits, or guideline emission limits. The commenter's
suggested standards and guidelines are based on the lowest
emission level achieved by all units, whereas the EPA
considers it more appropriate to allow for variability in
performance of similarly well-designed and well-operated
APCD's that represent the best type of control technology.
The standards and guidelines are based on the upper bound of
performance for units equipped with the technologies that
would be required to achieve the emission levels selected as
MACT, assuring that plants equipped can achieve these levels
of control.
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3.4.2 Municipal Waste Combustor Qrcranics
Comment: One commenter (IV-D-98) said the MACT floor for
the NSPS is based on SD/FF and this technology can not
continuously achieve 20 ng/dscm. The commenter urged the EPA
to select a dioxin/furan emission level of 60 ng/dscm as the
NSPS MACT floor. The commenter said an analysis of the data
submitted with their comment letter for 14 SD/FF-equipped
plants show that eleven plants can achieve 20 to 30 ng/dscm
consistently and that three plants exceed 30 ng/dscm. The
commenter said long-term data from the units at the Fairfax
MWC average 11 to 70 ng/dscm, with a plant average of
32 ng/dscm, which demonstrates the variability that can occur
even between identical units at the same site. The commenter
said the data used in the 1991 NSPS show that Stanislaus could
achieve 10 ng/dscm and Babylon could achieve 30 ng/dscm, yet a
review of the 5-year data from these plants would show the
opposite results. The commenter concluded that these data
prove the floor is not continuously achievable over the long
term.
Response: At proposal, MACT (SD/FF/SNCR/carbon
injection) rather than the MACT floor (SD/FF) was the basis
for the proposed standards. Data from 12 units received since
proposal indicate that new units equipped with SD/FF/SNCR/
carbon injection can comply with the proposed MACT-based
standards. The final dioxin/furan emission limits remain the
same as proposed.
3.5 SELECTION OF MAXIMUM ACHIEVABLE CONTROL TECHNOLOGY FOR
MUNICIPAL WASTE COMBUSTOR EMISSIONS
3.5.1 General Comments on Emission Limits
Comment: One commenter (IV-D-32) recommended that the
NSPS Hg emission limits be phased in with the NSPS
dioxin/furan emission limits, since they are both dependent on
carbon injection and optimization will be necessary to
accommodate site-specific Hg inlet levels. One commenter
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(IV-D-98) recommended that the EPA promulgate an
"optimization" process, particularly for organics, PM, and Hg.
The commenter suggested that a 3- to 5-year optimization
process would include an interim final limit, a consensus
standard optimization protocol with procedures for parametric
sensitivity tests, and a final limit that would include
related fixed operating conditions. In support of this
concept, the commenter pointed to the long-established
practice of using similar test-burn protocols, which set final
enforcement limits for plants that incinerate RCRA hazardous
wastes. The commenter also mentioned the fact that several
States such as New York are already using similar optimization
approaches for MWC's. The commenter attached a copy of the
N0X control optimization protocol for the Huntington, New York
MWC plant.
Response: The EPA is required by the Act to promulgate
standards for these pollutants, not site-specific optimization
programs. The EPA has proposed a three-year optimization
schedule for dioxins/furans to allow those plants that
commence construction after September 20, 1994, but on or
before September 22, 1997, to meet an interim dioxin/furan
emission limit of 30 ng/dscm total mass for the first 3 years
following the date of initial startup. Thereafter, the plants
will be expected to meet the final emission limit of
13 ng/dscm total mass. To encourage further dioxin/furan
emissions reductions at each site, an option for reduced
testing is being included in the final rule that allows a site
to test only one unit per year as long as dioxin/furan
emissions remain below a level of 7 ng/dscm. Refer to the
periodic testing section (section 3.8.1) for a more detailed
description.
A 3-year "phase in" for Hg is unnecessary. The
performance levels required for dioxins/furans control are
more stringent than for Hg. The final NSPS Hg emission limit
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is stringent but achievable. Although the final standards
include the proposed 3-year phase in for dioxins/furans, not
all plants are expected to require the phase-in period.
Twelve MWC units at 5 MWC plants have initiated operation of
SD/FF/SNCR/carbon injection control systems since proposal,
and all 12 units are achieving the 13 ng/dscm dioxin/furan
emission limits (in addition to achieving all of the other
pollutant emission limits -- PM, Cd, Pb, Hg, N0X, SC>2, and
HC1) .
Comment: One commenter (IV-D-98) recommended that
long-term averaging of emission measurements be an alternative
means of compliance, either on a cumulative or multi-year
rolling average basis. The commenter stated that this method
would minimize short-term perturbations, and would be
especially appropriate for PM, Cd, Hg, and dioxins/furans.
Response: Long-term averaging of emissions is
unnecessary. Monitoring and control of parameters such as
load and PM APCD inlet flue gas temperature will reduce short-
term perturbations of dioxin/furan emissions. The percent
reduction option for Hg should be adequate to accommodate
occasional spikes due to variability in the Hg content of the
incoming waste stream. Recent tests from 12 units at 5 plants
equipped with the APCD's that will be required to achieve the
MACT emission limits (SD/FF/SNCR/carbon injection) indicate
that new units are capable of complying with the standards.
In fact, the data from these plants indicate that dioxin/furan
emission levels lower than the final standards are achievable.
An option for reduced dioxin/furan testing for plants
achieving dioxin/furan emission levels lower than 7 ng/dscm is
being promulgated. Refer to the periodic testing section
(section 3.8.1) for a more detailed description of this option
for reduced testing.
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3.5.2 Municipal Waste Combustor Qrcranics
Comment: Several commenters (IV-D-02, IV-D-18, IV-D-28,
IV-D-37, IV-D-38, IV-D-41, IV-D-43, IV-D-44, IV-D-55, IV-D-56,
IV-D-67, IV-D-68, IV-D-82, IV-D-85, IV-D-96, IV-D-104,
VI-B-02, VI-B-04, VI-B-05, VI-B-06) protested the MACT
standard for dioxins/furans being more stringent than the MACT
floor. Several commenters (IV-D-43, IV-D-44, IV-D-56,
IV-D-68, IV-D-82, IV-D-85, IV-D-104, VI-B-04) maintained that
the results of limited pilot or experimental testing for
dioxins/furans control are not sufficient justification for
establishing more stringent standards. The commenters said
the dioxin/furan emission limit is not based on emission
levels at a specific plant and, therefore, has not been
demonstrated to be achievable in practice as required by the
Act. Four commenters (IV-D-28, IV-D-43, IV-D-44, VI-D-67)
cited the 3-year optimization schedule as proof of the
uncertainty of what dioxin/furan level can be achieved.
One commenter (IV-D-56) said the EPA's conclusion that
carbon injection can achieve a 50-percent reduction in
dioxin/furan emissions is only a theory, and using a theory to
set a standard borders on arbitrary and capricious. Four
other commenters (IV-D-28, IV-D-37, IV-D-38, IV-D-44) also
disagreed with the EPA's assumption of 50-percent reduction
for carbon injection. Another point of contention raised by
two commenters (IV-D-18, IV-D-85) was that the Camden MWC
testing program may have achieved its performance due to some
factor other than carbon injection (e.g., higher PM
concentrations for baseline runs than for the test runs).
Several commenters (IV-D-18, IV-D-28, IV-D-85, VI-B-02,
VI-B-05, VI-B-06) suggested that the EPA should collect more
operating data from systems now coming on line with carbon
injection before establishing limits.
Two commenters (IV-D-32, IV-D-75) said the proposed
dioxin/furan standards are achievable using current technology
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with or without carbon injection. One commenter interpreted
the proposal to mean that even though the standards were based
on carbon injection, it is not required as long as the
standard is met.
Response: The carbon injection data upon which the NSPS
dioxin/furan emission limit is based were from full-scale
tests at commercial MWC's, not experimental or pilot tests.
The Camden MWC test was the primary test used to assess carbon
injection performance prior to proposal. Data from several
MWI's, an HWI, and several European MWC's were also available.
This information is available in docket A-90-45, item number
II-B-39. These tests, including data received since proposal,
show that an additional 50-percent or greater reduction of
dioxin/furan emissions can be achieved with carbon injection.
In addition, the phase-in period for new plants that
commence construction after September 20, 1994, but on or
before September 22, 1997, allows for fine-tuning of the
carbon injection rates to determine the carbon injection rate
needed for consistently achievable emission reductions,
although new data indicate this phase-in period may not be
necessary for MWC plants.
Since proposal, data have been received from 12 units at
the following 5 new plants that are equipped with
SD/FF/SNCR/CI controls: Lee County, Florida; Falls/Bucks
County, Pennsylvania; Hennepin County, Minnesota; Union
County, New Jersey; and Onondaga, New York. The dioxin/furan
levels reported ranged from less than 1 ng/dscm to
11.6 ng/dscm total mass. Eleven out of 12 units at these
plants are achieving dioxin/furan emission levels less than
7 ng/dscm total mass.
The data summarized above supports the EPA's conclusion
that the MACT floor emission level for dioxins/furans is based
on the use of carbon injection. The existing data support the
use of carbon injection as a control technology for
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dioxins/furans and the achievability of the standards and
guidelines. The dioxin/furan emission limit for new plants
will be promulgated as proposed (13 ng/dscm). This
dioxin/furan limit is consistent with the need to act now to
ensure that dioxin/furan emissions from MWC's are minimized to
the extent possible, in light of the concerns associated with
dioxins/furans.
Additionally, the commenter (IV-D-75) is correct that if
an MWC can meet the dioxin/furan limit and the limits for
other regulated pollutants without the use of carbon
injection, then carbon injection is not required by the NSPS
or emission guidelines. A plant is free to use any technology
as long as the emission limits are met.
Comment: One commenter (IV-D-104) discussed a Method 23
validation study, and indicated that some of the dioxin data
used by the EPA for the proposed dioxin/furan NSPS is below
the practical quantitation limit of the method and cannot be
distinguished from background noise. The commenter determined
the practical quantitation limit to be less than 10 ng/dscm
total mass using propagation of error techniques.
Response: The EPA has reviewed available dioxin/furan
data to determine the achievable performance levels of SD/FF.
The target detection limit for this method is considered to be
adequately low, such that the NSPS emission limit of
13 ng/dscm is not considered below detectable limits. The
commenter's determination of a practical quantitation limit
may be biased high because of the use of propagation of error
techniques to make the determination.
3.5.3 Municipal Waste Combustor Metals (Other Than Mercury)
and Particulate Matter
Comment: Five commenters (IV-D-18, IV-D-28, IV-D-85,
IV-D-98, IV-D-137) stated that the NSPS emission limits for PM
are very tight and will push FF's to the limits of their
control capabilities. Two commenters (IV-D-18, IV-D-85)
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indicated that even well-run units may at times have
excursions above the standard. The commenters (IV-D-18,
IV-D-85, IV-D-98) maintained that, compounding the difficulty
in meeting the tight limit, there is a possibility of
interference by activated carbon with particulate control,
particularly on ESP performance. Two commenters (IV-D-18,
IV-D-98) indicated that tighter acid gas control and carbon
injection will result in increased grain loading.
The commenters warned that it is inappropriate to
establish a MACT standard for PM for new units when data are
not available to prove they can be achieved on a continuous
basis when activated carbon is being injected. One commenter
(IV-D-98) said that although the tests at Camden did not
indicate direct interference from carbon injection, literature
reports that a significant reduction occurred in ESP PM
efficiency following a carbon injection test at an
SD/ESP-equipped plant. The commenter said the EPA should
investigate this issue at the three plants that the EPA said
were going into commercial operation in 1994. Two commenters
(IV-D-18, IV-D-85) recommended that a limit of 0.01 gr/dscf
(21 mg/dscm) can be reliably met, and noted that this would
still be less than two-thirds of the 1991 NSPS limit.
Response: The EPA agrees that the proposed PM limits
were very stringent. Based on data submitted by commenters,
the EPA has revised the continuously achievable performance
level for new plants from 15 mg/dscm (proposed) to 24 mg/dscm.
Data received by the EPA from 12 units at 5 plants equipped
with SD/FF's and carbon injection (Lee County, Onondaga
County, Union County, Falls/Bucks County, and Hennepin County
MWC's) indicate that all are achieving this PM emission level
as well as the final emission limits for the other regulated
pollutants.
Comment: One commenter (IV-D-18) disagreed with the
EPA's approach of using actual test data for Cd and Pb
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independent of the actual PM emissions data. The commenter
stated that Cd and Pb emissions should be considered to be a
percentage of total particulate, and should be directly linked
to the PM standard. The commenter claimed that from a
technical point of view the Cd and Pb standards effectively
negate the PM standard, and the commenter indicated that to
achieve the Cd and Pb standards, a PM emissions level of
0.002 gr/dscf may be required (which is below the proposed PM
standard of 0.007 gr/dscf). The commenter stated that if the
EPA insists on establishing emission limits for Cd and Pb,
they should be ratioed upward to 0.015 and 0.153 mg/dscm
corrected to 7 percent O2, respectively.
In support, the commenter pointed out that the EPA has
indicated that control of Cd and Pb are generally related to
control of PM emissions, that the potential for absorption of
these metals is greatest on fine PM due to the increased
surface area, and that the control efficiency of these metals
may be lower than that for PM. The commenter said that the
EPA reported the reduction from baseline levels to be 80, 94,
and 98 percent for PM, Cd and Pb, respectively. The commenter
indicated that for EPA's logic to be sound, the reductions for
Cd and Pb should be lower than that for PM.
One commenter (IV-D-32) stated that the proposed PM, Pb,
and Cd standards all are readily achievable. The commenter
cited PM data from the Commerce, Marion County, Spokane,
Warren County, Indianapolis, and Huntington MWC plants along
with data from the docket as evidence that the proposed PM
limits are achievable.
Response: The NSPS for Cd and Pb were based on emissions
data from SD/FF-equipped units. The EPA agrees that control
of these metals may be related to PM control.
The proposed emission limits for PM, Cd, and Pb represent
over 99 percent control of uncontrolled levels of these
pollutants from large and small plants (not 80, 94, and
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98 percent, respectively, as cited by the commenter). As
discussed elsewhere in this section, the final PM emission
limit is 24 mg/dscm, which is an increase from the 15 mg/dscm
level proposed; however, the final PM limit still represents
over 99 percent control. Upon review of the EPA's data and in
consideration of the revised PM standard, the Cd and Pb
standards were also revised. The final Cd and Pb emission
limits are 0.02 mg/dscm and 0.20 mg/dscm, respectively
(proposed values were 0.01 mg/dscm and 0.1 mg/dscm,
respectively). In addition to the emissions data in the
proposal docket, data from five plants that have recently
begun operation (Union County, Lee County, Onondaga,
Falls/Bucks County, and Hennepin County MWC's) demonstrate
that the emission limits for PM, Cd, and Pb are simultaneously
achievable.
3.5.4 Municipal Waste Combustor Metals (Mercury)
Comment: Several commenters (IV-D-18, IV-D-37, IV-D-43,
IV-D-44, IV-D-55, IV-D-56, IV-D-68, IV-D-85, IV-D-96, IV-D-98,
VI-B-04) asserted that the Hg emission limit should be revised
due to lack of demonstrated data.
Three commenters (IV-D-18, IV-D-85, IV-D-98) stated that
the proposed Hg standard is based on a small number of
short-term tests using temporary control equipment at only two
facilities, and expressed concern as to whether EPA's carbon
injection data are indicative of performance at long-term
permanent installations. One commenter (IV-D-18) maintained
that commercial application of technology often isolates
problems not observed during short-term test runs.
One commenter (IV-D-98) said the two tests used by the
EPA as the basis of the Hg standard lacked sufficient
repetitions of both control and test runs to provide good
statistical reliability to the numerical conclusions. The
commenter referred to a paper which the commenter said
demonstrates that the proposed limits are not achievable. The
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commenter said the paper analyzed the Stanislaus data and
concluded that 95 percent of individual tests conducted to
comply with the standard will achieve Hg reduction of at least
80 percent and an outlet concentration of 112 ng/dscm or less.
The commenter warned that the EPA may not set a not-to-exceed
limit in which at least 5 percent of the performance tests are
expected to fail, and pointed out that the failure rate would
be higher at the 85-percent Hg reduction level specified by
the standard. The commenter said the EPA must set a limit
lower than 80-percent removal.
One commenter (IV-D-85) said the reports from pilot test
run by the EPA at an MWC with SD/FF/CI in 1991 specifically
stated that achievable Hg outlet concentrations are
100 ]jg/dscm or 80-percent removal by weight. The commenter
said the EPA failed to discuss the technical reasons why they
chose to propose a MACT standard of 85-percent removal, which
was not supported by the pilot tests.
Two commenters (IV-D-32, IV-D-108) agreed that the
proposed Hg standards are achievable using current technology,
including carbon injection. One commenter (IV-D-32) cited one
report showing 99-percent Hg control efficiency by an SD/FF
alone, and another showing greater than 98-percent reduction
to a level below 0.050 mg/dscm using carbon injection with an
SD/FF. The commenter also cited another paper which presented
results of 0.070 mg/dscm using Sorbalit technology as an
alternative to carbon injection. One commenter (IV-D-108)
noted that the 85-percent reduction standard based on the
Stanislaus and Camden County tests is reasonable since more
recent data show actual efficiencies to be well above
95 percent.
Response: Activated carbon injection has been used
commercially on MWC's in Europe and Canada, where the
performance capabilities of this control technology have been
demonstrated; however, it is not possible to compare data
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gathered in Europe and Canada to U.S. data due to differences
in test methods and other procedures. For these reasons, the
EPA conducted testing at two U.S. MWC's (Stanislaus County and
Camden County) to assess the capabilities of this control
technology.
The EPA's initial analysis of data from the Stanislaus
County MWC showed that 80-percent reduction was achievable.
However, subsequent analyses based on the combined knowledge
gained from the Stanislaus County, Camden County, and other
tests concluded that higher Hg reductions could be
continuously achieved by increasing the carbon feed rate.
This analysis concluded that at a carbon injection rate of
approximately 100 mg/dscm (0.8 lb carbon/ton MSW) the proposed
limit of 80 mg/dscm or 85 percent reduction would be achieved.
This analysis also examined the impact of further increasing
carbon feed rates to achieve even lower Hg emissions and the
impact of variability in the Hg content of MSW. The EPA did
an economic analysis (refer to docket No. A-90-45; item
number II-A-13) and determined that the costs of carbon
injection are reasonable.
In addition to the EPA tests, five U.S. MWC's that began
using activated carbon injection technology since 1994 (Union
County, Lee County, Onondaga County, Falls/Bucks County, and
Hennepin County MWC's) are meeting the proposed limits.
Comment: Two commenters (IV-D-55, IV-D-85) said the EPA
failed to take into account the impact of switching from
Method 101A to Method 29. The commenters were concerned that
using Method 29 for performance testing will result in higher
measured emission levels than the NSPS and emission guidelines
if data used to set the NSPS and guidelines were collected
using Method 101A.
Response: The difference between the methods, which was
estimated based on a statistical analysis of Method 101A and
Method 29 at Stanislaus (a report prepared for EMB
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statistically compared Methods 29 and 101A), does not impact
the resulting NSPS and guidelines. What it is most important
is that the activated carbon data from both the Stanislaus and
Camden test programs were collected using Method 29. In
September 1994, Method 29 was proposed for determining
emissions from MWC's, MWI's, and power plants. The method is
identical to EPA's Office of Solid Waste's multimetals method,
except that a filtration and analysis step was added for
Method 29 (see proposal for Method 29 59 FR 48259). The
additional step protects against the loss of Hg in the
manganese oxide precipitate that can form in the acidified
potassium permanganate (KMn04/H202) impingers and results in
similar sample preparation and analysis requirements for EPA
Methods 29 and 101A. Thus, any Hg in the precipitate should
have been included in the analytical sample. As such, the EPA
is confident in the results achieved with Method 29.
Comment: Two commenters (IV-D-24, IV-D-108) recommended
that the EPA require plants to conduct tests to determine
optimal reagent injection rates. One commenter (IV-D-24) said
operators should be required to adhere to these carbon and
alkaline reagent injection rates at all times and provide
authorities with records verifying regular purchase of each
reagent consistent with the optimal usage rates. The
commenter cited several references to support the importance
of carbon and reagent feed rates in attaining desired control
levels. The commenter also claimed that Hg regulations for
MWC's promulgated by New Jersey in September 1994 have such a
requirement. A second commenter (IV-D-108) also cited the New
Jersey regulations and said that the State requires
optimization of the Hg APCD's with reasonable reagent use and
then requires monitoring of the minimum reagent injection
ratio to ensure that the control efficiency is maintained.
The commenter attached a copy of the New Jersey adoption
document for the State rule (NJAC 7:27-27) adopted
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September 23, 1994. The document includes comment summaries
and responses on the proposed rule.
Response: For alkaline reagent for acid gas control, the
EPA is not requiring a particular injection rate because SO2
is required to be continuously monitored. The EPA proposed a
requirement that plants using carbon injection for Hg control
measure and record the amount of carbon injected for each
8-hour period of operation. This has been revised to a 1-week
period. Refer to section 3.5.2 for a description of carbon
feed rate monitoring for dioxins/furans and Hg.
Comment: Three commenters (IV-D-17, IV-D-65, IV-D-120)
stated that the numerical emission limitation contained in the
proposed NSPS and guidelines should be reduced from
0.08 mg/dscm to at least 0.065 mg/dscm. One commenter
(IV-D-17) said this level should be considered an interim
level with further reduction made incrementally over time to
account for the "projected decline in mercury content" of
waste products.
One commenter (IV-D-65) said this level is better because
it forces more recovery of Hg. The commenter asked the EPA to
adopt standards matching those currently proposed by
New Jersey, as follows: 0.065 mg/dscm until January 1, 2000
and 0.028 mg/dscm thereafter.
One commenter (IV-D-120) recommended the use of a two-
tier limit as was adopted in Minnesota. The commenter claimed
that the EPA has effectively proposed a short-term limit of
80 ]ig/dscm, which takes into account the upper level of Hg
emissions achieved by a well-operated MWC during a single
testing event with a high degree of confidence. The commenter
added that the EPA should establish a long-term emission limit
of 60 ]jg/dscm, which will ensure that the atmospheric loading
from MWC's is minimized and most accurately represents overall
emissions to the environment. The commenter included a
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technical work paper which discusses how this long term value
was established.
Response: The EPA has established limits that
effectively control the emissions of Hg from MWC's based on
the available domestic data. These limits include an emission
limit of 0.080 mg/dscm and an alternative 85-percent reduction
requirement that is more stringent than the 80-percent
alternative reduction required by New Jersey. If, when the
NSPS and emission guidelines are periodically reviewed, it
becomes apparent that more stringent Hg limits are
continuously achievable and cost effective, the EPA will
revise the limits at that time.
Comment: One commenter (IV-D-32) informed the EPA that
Hg trapped in spray drying and carbon injection processes is
not released by sorbents via volatilization nor leaching. The
commenter cited two reports in support.
Response: The EPA acknowledges this commenter's support.
3.5.5 Nitrogen Oxides
Comment: One commenter (IV-D-32) claimed a NOx limit of
150 ppm with an alternative of 50-percent reduction in
emissions could be achieved for a small incremental cost. The
commenter presented data on 17 foreign and domestic plants
equipped with SNCR. The commenter indicated that the
guaranteed NOx reductions ranged from 41 to 75 percent, with
ammonia slip ranging from 6 to 25 ppm. The commenter noted
that with independent injection level controls, reductions of
60 to 70 percent and 100 ppm are achievable with normalized
stoichiometric ratios of 1.5 or greater and ammonia slip at or
below 20 ppm. The commenter pointed out that without
independent level control, a reduction of 50 percent and an
emission level of 150 ppm are achievable. The commenter
maintained that these levels can be guaranteed by vendors and
the 150 ppm level provides flexibility to units with high
uncontrolled levels. The commenter (IV-D-32) noted that
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MB/rotary, fluidized bed, and MOD/EA combustors typically have
uncontrolled levels below 150 ppm. In further support of a
150 ppm limit, the commenter noted that 75 percent of the
MWC's in the U.S. are in ozone non-attainment areas or the
northeast ozone transportation region, and the ozone Transport
Commission's limit of 0.2 lb/MMBtu for NOx from large boilers
would correspond to about 100 ppm for a MB/rotary unit burning
waste with a 5,000 Btu/lb heating value.
Response: The EPA has gathered and analyzed additional
data since proposal. The additional data collected are from
the Stanislaus MWC (collected January through March 1994 and
June through August 1994). The data indicate that a NOx level
of 150 ppmv is achievable on a continuous basis. This
corresponds to an average NOx reduction from the Stanislaus
MWC of 45 to 55 percent. The NSPS for large plants being
promulgated is, therefore, 150 ppmv, which is lower than the
180 ppmv level proposed.
Comment: One commenter (IV-D-74) suggested that other
control technologies such as flue gas recirculation be
evaluated for control of NOx emissions from small sources
since the current proposal allows small plants to remain
uncontrolled.
Response: Other control technologies have been examined
(refer to EPA-600/R-94-208 and EPA-450/3-89-27d); however, the
percent reductions attainable using many of these technologies
are low and data are limited. Flue gas recirculation, for
example, involves mixing cooled flue gas with combustion air
to both lower O2 in the combustion air supply and suppress
flame temperatures by increasing inerts (N2 and CO2) in the
combustion air system. Data indicate, however, that there is
also an increase in CO emissions. Additionally, there are
only limited quantitative data on the levels of NOx reduction
achieved by this technique (expected to be on the order of 10
to 30 percent). Although it was not the basis of the
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performance standards, an individual owner or operator of an
MWC is free to select this or any other approach or technology
to achieve the NSPS.
Comment: Several commenters (IV-D-28, IV-D-54, IV-D-55,
IV-D-67, IV-D-85, IV-D-87, IV-D-99, VI-B-02, VI-B-05, VI-B-06)
described concerns regarding ammonia slip from the use of SNCR
for N0X control. The commenters were concerned that ammonia
slip at the 180 ppmv NOx control level is not addressed in the
proposed regulation.
Four commenters (IV-D-28, VI-B-02, VI-B-05, VI-B-06) said
that New Jersey and New York are beginning to consider ammonia
slip in their SIP's. One commenter (IV-D-99) noted that
several States have ammonia slip emission limits as well as
NOx limits, and recommended that the EPA establish levels for
both NOx and ammonia that are consistent and practical based
on existing technology.
Response: The NOx levels being promulgated for new and
existing MWC units at large MWC plants represent a 35- to
55-percent reduction from uncontrolled levels. Data show that
this level of control is not associated with high levels of
ammonia slip, which are expected to be less than 10 ppmv.
While the EPA is not required to set a limit for ammonia under
section 129, States are free to impose additional limitations
as they deem appropriate.
3.5.6 Good Combustion Practices
Comment: Two commenters (IV-D-85, IV-D-98) said that the
EPA has not defined the term "MWC unit load" in the proposal,
such that the relationships between steam flow measurements,
the definition of "maximum MWC unit capacity," and throughput
limitations are not clearly established.
Response: The term "MWC unit load" is being defined in
the final NSPS and guidelines as the steam flow of the boiler,
which can be measured as steam flow or feedwater flow as
described in proposed § 60.58b(i). The definition of "maximum
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MWC unit capacity" (proposed § 60.51b) and the throughput
limitation description (proposed § 60.53b(b)) are clarified to
reflect this change in the definition of MWC unit load.
Comment: Several commenters (IV-D-18, IV-D-28, IV-D-30,
IV-D-44, IV-D-75, IV-D-80, IV-D-82, IV-D-85, IV-D-98,
IV-D-120) advised against removal of the flow orifice or flow
nozzle, because welded-in devices are not designed for this
type of repeated maintenance and would require shutdown of the
unit for extensive periods. They also said that removal and
bench calibration of entire steam flow measurement systems is
expensive and unnecessary. One commenter (IV-D-75) said the
factory-calibrated orifice plate should be adequate as long as
it is used consistently. One commenter (IV-D-44) pointed out
that because the water used is of such a high purity, there is
little potential for the flow element to degrade. The
commenter (IV-D-44) also noted that the accuracy of the flow
element far exceeds the level required for the proposed 4-hour
averaging period.
One commenter (IV-D-98) informed the EPA that flow
elements recently removed at two MWC's that had been operating
for 5 to 7 years were measured, and both flow elements were
within the tolerances of their original manufacturing
specification of 0.0005 inches. Four commenters (IV-D-44,
IV-D-54, IV-D-80, IV-D-95) recommended that the steam flow
measurement elements (orifice plate, vortex shredder bar,
annubar, etc.) be visually inspected every 3 years.
Several commenters (IV-D-18, IV-D-28, IV-D-30, IV-D-85)
recommended that instead of requiring removal of the flow
orifice or flow nozzle, the EPA should require that the
differential pressure transmitters be properly calibrated
according to the manufacturer's recommendations prior to the
annual dioxin/furan test. Two commenters (IV-D-54, IV-D-80)
suggested that the signal conversion elements, which are
subject to drift, be calibrated annually.
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Response: Based on the commenters' input, the EPA is not
promulgating any requirements for periodic inspection and
calibration of orifice plates or other flow measurement
devices. Absolute accuracy is not the key issue. What is
important is the relative accuracy between measurements and
relative accuracy will be maintained because the same plate
used during the annual dioxin/furan test will continue to be
used for load measurements until the next retesting. However,
the promulgated rules do require annual calibration of the
transducers and signal converters in accordance with the
manufacturers' instructions and before each performance test.
Records must be kept documenting calibration of instruments.
Comment: Several commenters (IV-D-18, IV-D-28, IV-D-30,
IV-D-44, IV-D-54, IV-D-80, IV-D-85, IV-D-120) strongly
recommended that alternative technologies other than the
proposed measurement of steam flow be allowed for monitoring
MWC unit load. One commenter (IV-D-75) suggested that a menu
of options should be available for load measurement to afford
operators flexibility, and should include alternatives such as
gross power output and refuse charging rate. One commenter
(IV-D-120) noted that not all plants use orifice plates, which
makes the application of ASME PTC 4.1 inappropriate.
One commenter (IV-D-03) suggested that the measurement of
load could alternatively be based on fuel feed rate (in Btu
per hour) instead of on steam flow. Several commenters
(IV-D-18, IV-D-28, IV-D-30, IV-D-44, IV-D-54, IV-D-85,
IV-D-120) suggested operators should have the option to
measure plant capacity using boiler feedwater flow, which has
been properly corrected to account for sootblowing,
desuperheating, blowdown, and miscellaneous flows. Two
commenters (IV-D-74, IV-D-103) did not support the use of
boiler feedwater flow as an alternative to steam flow
measurement.
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Two commenters (IV-D-54, IV-D-80) strongly recommended
that alternative technologies other than the proposed ASME PTC
procedures (orifice plate and differential pressure
transmitter) be allowed for steam flow measurement if they
exhibit equivalent accuracy. One commenter (IV-D-80)
suggested that flexibility must be provided for MWC's that use
other methods such as annubar, vortex shredder, or pitot.
Five commenters (IV-D-44, IV-D-74, IV-D-75, IV-D-98,
IV-D-103) contended that, for a number of reasons, measuring
flue gas volumetric flow rate is inadequate. One commenter
(IV-D-44) cited several load measurement uncertainties
regarding the use of flue gas volumetric flow rate.
One commenter (IV-D-44) informed the EPA that the ASME
PTC 34 committee is evaluating use of a heat balance around
the economizer (the "ECHB" method) to determine flue gas flow
rate. The commenter said this method is felt to have a lower
uncertainty, but it has not yet been quantified. One
commenter (IV-D-103) recommended direct flue gas measurement
as consistent with the requirement under 40 CFR 264.345(b)(4)
under RCRA and under part 75. The commenter listed several
measurement methods and said a detailed method description can
be found in EPA 40 CFR 264, Part 75, and in the "Engineering
Handbook for Hazardous Waste Incineration - Draft 2 of May 31,
1990".
Response: The EPA agrees that there are several possible
alternative methods for monitoring MWC unit load, and that the
best method may depend on site-specific conditions. With this
consideration, the EPA is promulgating steam flow measurement
and a water flow measurement alternative for the monitoring of
MWC unit load and, as specified in the General Provisions,
plants may petition the regulating authority for approval of
an alternative method.
Comment: One commenter (IV-D-102) requested that the EPA
clarify the CO averaging time for MWC's that are designed as
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coal/RDF mixed fuel-fired units but operate as RDF-stoker
units. The commenter noted that the EPA has three options (in
preferred order): (1) Require the compliance averaging time
based on the design of the unit (4-hour for coal/RDF mixed
fuel); (2) allow the averaging time to be based on the
operation of the unit (24-hour for RDF-stoker) through a
federally-enforceable permit amendment, but only after the
owner/operator permanently removes from the MWC unit and plant
property all components or equipment that were solely
constructed/installed for the burning of coal; or (3) allow
the permitting authority to define the operating mode in a
federally-enforceable construction or operating permit and
thus define the averaging time. The commenter asserted that
the first option is preferred because it simplifies
enforcement and is consistent with EPA's logic with respect to
determining plant capacity.
Response: The coal/RDF mixed fuel CO standard originally
promulgated in 1991 and in September 1994 was intended to be
applicable to pulverized coal-fired boilers that cofire fluff
RDF. The CO standards promulgated after consideration of
these comments are to be 150 ppmv with a 4-hour averaging time
for existing and new units. It should be noted that all
coal/RDF mixed fuel units that fire less than 30 percent by
weight of RDF are exempt from complying with the MWC emission
standards by provisions of section 129 of the Act. These
units will be required to meet the applicable emission limits
for coal-fired units.
Coal/RDF mixed fuel units that employ spreader stoker
combustors are required to comply with the CO emission limits
for RDF spreader stokers, which contain a 24-hour averaging
time. When switching from RDF to coal-firing, mixed fuel
units must comply with the CO, load, and PM control device
temperature requirements until all RDF has been cleared from
the combustor grate. When RDF has been cleared from the
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combustor grate, the unit will be exempt from compliance with
the MWC CO, load, and temperature requirements.
Comment: One commenter (IV-D-24) criticized the EPA for
not gathering new data for CO and instead relying on the BID
prepared for the 1991 standards and guidelines. The commenter
claimed that this means the EPA has not complied with the
requirements of section 129 of the Act.
Response: Section 129 of the Act does not require the
EPA to collect new data for establishing CO levels.
Section 129 requires that the control levels are established
based on MACT. Currently there are few options available
regarding CO control other than GCP. The CO levels determined
to represent GCP in the 1991 NSPS and emission guidelines are
still valid for each combustor type. The only changes that
will be promulgated are clarifications for mass burn rotary
refractory units, pulverized coal/RDF mixed fuel-fired
combustors, and spreader stoker coal/RDF mixed fuel-fired
combustors.
Comment: Four commenters (IV-D-24, IV-D-51, IV-D-74,
IV-D-103) objected to a CO standard that varies by combustor
type. One commenter (IV-D-24) maintained that this allows
some plants to be lax in optimizing their combustion
operations. Three commenters (IV-D-51, IV-D-74, IV-D-103)
objected to any CO standard above 100 ppm. Two commenters
(IV-D-74, IV-D-103) said it should be 100 ppm with a 4-hour
average. One commenter (IV-D-51) alleged that the emphasis of
the standards appears to be to minimize the release of
dioxins/furans, rather than to control production of them.
This commenter warned that the proposed limits do not mandate
optimal burn conditions and, in effect, allow the production
of high levels of dioxin. Two commenters (IV-D-74, IV-D-103)
said there is a direct relationship between elevated CO and
dioxin/furan formation. In support, these commenters cited an
attached paper on MWI emissions and said that a test done at
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the Pittsfield MWC showed that CO levels above 100 ppm were
associated with higher dioxin/furan emissions. These
commenters described CO as a surrogate parameter for
dioxin/furan information that is a lower cost alternative to
dioxin/furan testing. Another commenter (IV-D-24) who also
cited the ASME New York State Energy Research and Development
Authority ("NYS/ERDA") Pittsfield tests said the tests showed
that CO should be measured using a short-term (1-hour)
averaging time to minimize dioxin/furan formation.
Three commenters (IV-D-24, IV-D-74, IV-D-103) contended
that the proposed standards penalize more efficient combustors
with stricter limits and allow less efficient combustor types
to operate inefficiently. They contended that the less
efficient combustors are at times capable of meeting less than
50 ppm and cited tests from Stanislaus, Commerce, Marion,
Baltimore, and Clairmont which showed CO levels of 19 to
49 ppm. Pigeon Point was listed at 7 ppm and Oswego was
listed at less than 20 ppm. One commenter (IV-D-103) claimed
there is no evidence in the background document that a good
faith effort was made to investigate those operating practices
which optimize combustion. Two commenters (IV-D-24, IV-D-103)
said the Penobscot, Maine plant, which the EPA includes in its
data base and considers an example of good combustion by an
RDF plant, has no impetus to operate any more efficiently than
its lax permitted level of 400 ppmv, 4-hour average. One
commenter (IV-D-24) also criticized the use of data from the
mid-Connecticut MWC because of questionable operating
conditions.
One commenter (IV-D-103) indicated that a 4-hour
averaging period is appropriate because the majority of MB/WW
units have a waste retention time on the grate of up to one
hour which does not provide adequate time for an operator to
make a good faith effort to correct upsets and still achieve a
limit representative of GCP. The commenter cited an EPA MWC
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document for GCP (EPA-600/8-89-063) which indicates that the
MB/WW combustors in Millbury, Maine will exceed a CO CEM
emission level of 58.4 ppm once every year in a 4-hour block
period.
Two commenters (IV-D-74, IV-D-103) listed five factors
that contribute to high CO emissions in MWC's. Three
commenters (IV-D-24, IV-D-74, IV-D-103) said the EPA's 1987
GCP guidelines stipulated that 50 ppm CO (4-hour average) with
6 to 12 percent O2 is an indicator of good combustion.
Three commenters (IV-D-24, IV-D-74, IV-D-103) said Canada
has a GCP requirement of 50 ppm CO and the Netherlands has a
standard of 44 ppm (corrected from 50 mg/m^). Two commenters
(IV-D-74, IV-D-103) also cited the disparity between EPA's MWC
standard and the HWI standard, which has a single limit for
all new and existing incinerators. The commenters asserted
that, in some cases, the combustors, control equipment, and
pollutants are similar, and both MWC's and HWI's require
similarly high combustion efficiency to minimize emissions.
These two commenters recommended that the EPA review EPA's
National Hazardous Waste Combustion Strategy and propose a
similar approach which specifies high combustion efficiency.
Response: The CO concentration in the flue gas of each
MWC is related to the specific combustion conditions within
the unit. There are inherently different design and operating
conditions between different types of MWC's. These
differences and the fact that low CO emissions is a relatively
new requirement results in differences in the CO emission
limit that can be achieved by dissimilar MWC's.
For example, mass burn MWC's burn unprocessed waste in
deep beds and the residence time of the waste within these
combustors is approximately one hour. This large mass of
waste burns slowly, releasing combustion gases into a rather
large furnace volume. Careful metering of under and overfire
air into different furnace zones by computerized distributed
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control combustion systems results in stable, carefully
controlled combustion conditions and low levels of CO.
Spreader stoker/RDF combustors (also called RDF stokers)
burn processed waste by pneumatically injecting it through
feeders in the side of the furnace where it burns in a "semi-
suspension" fashion. Approximately 40 percent is burned in
suspension and the remainder is burned in a thin bed on a
traveling grate at the bottom of the furnace. The residence
time of the RDF on the traveling grater is approximately
20 minutes and the relative burn rate of waste is higher than
in mass burn combustors. In spreader stoker RDF systems, the
uniformity of combustion is highly dependent on RDF feed
conditions. Variations in the RDF feed rate or RDF properties
can result in fluctuations in combustion conditions that
result in higher CO flue gas concentrations. Minor combustion
upsets with associated CO excursions can also occur from RDF
feed chute or RDF feeder blockages. The frequency and
severity of feed upsets is both a function of the RDF
processing plant and the RDF feed system design.
Carbon monoxide emission limits for each type of
combustor are established using test or operating data to
determine the emission limit and averaging time which a
particular type of unit can achieve. State-of-the-art mass
burn waterwall MWC's have inherently stable combustion
characteristics and low CO levels. A 100 ppm CO emission
limit with a 4-hour averaging time has been established for
these types of units. In an EPA sponsored test at a mass burn
combustor in Marion County, Oregon in 1987, the combustor was
subjected to a number of different operating conditions
including changes to the under-to-overfire air ratio and the
overfire air distribution. CO concentrations at the inlet to
the unit's spray dryer never exceeded 37 ppm and emissions
under normal operating conditions were typically less than
20 ppm. While the unit was not attempting to control CO, the
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computerized distributed combustion control system maintained
high combustion efficiency and low concentrations of CO.
Evaluation of long term emission data from other state-
of-the-art mass burn waterwall facilities indicate that these
types of facilities can achieve a 100 ppm CO emission limit on
a 4-hour basis. In most cases these mass burn combustors will
operate at long term averages of less than 50 ppm to comply
with the 100 ppm (4 hour) emission limit. Experience
indicates that operation at CO concentrations between 50 and
100 ppm may be required due to problems associated with the
burning of wet waste.
Later in 1987, ABB Combustion Engineering began startup
testing at the Mid-Connecticut Resource Recovery Facility in
Hartford, Connecticut (Mid-Conn). The Mid-Conn facility
contains three RDF spreader stoker combustors, each designed
to fire approximately 660 tons/day of RDF. During startup,
the units typically operated with flue gas CO concentrations
of above 200 ppm. During a subsequent test program sponsored
by EPA and Environment Canada it was found that by steady-
state, CO emissions of less than 100 ppm could be achieved by
proper adjustment of the under and overfire air flow.
Improvements in the combustion control procedures were also
made at the ABB Combustion Engineering facility in Detroit
(the Greater Detroit Resource Recovery Authority Facility)
which finished construction shortly after the Mid-Conn
Facility. A statistical evaluation of CO emission data from
the Detroit facility indicated that although it could achieve
average long-term CO emissions of 70 to 80 ppm, it could only
achieve an emission limit of 150 ppm on a 24-hour basis due to
CO excursions associated with feed upsets.
The NSPS for RDF spreader stoker combustors promulgated
in 1991 incorporated a 150 ppm emission limit and a 24-hour
averaging time. However, the available data for RDF
combustors indicate that they will have to limit long-term
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average CO emissions to the range of 70 to 80 ppm to
compensate for feed upsets.
Carbon monoxide emissions from some types of commercially
operating MWC's are substantially higher than for modular and
mass burn units because until recently, attempts have not been
made to minimize CO emissions. In some cases, emission limits
of other types of combustors are higher than mass burn
combustors because of a lack of data showing they are capable
of achieving emission limits of less than 200 to 250 ppm.
The 4-hour CO emission averaging time is roughly the time
period required for a dioxin/furan emissions test. It is also
a reasonable minimum averaging period for combustors with
relatively stable operating conditions. A 24-hour averaging
period is needed for combustors that are prone to combustion
upsets.
The 4-hour averaging periods for steam load and PM
control device inlet temperature are consistent with the time
period necessary to conduct a dioxin test. Data from EPA
sponsored field tests have shown that compliance with a 4-hour
steam load limit and a 4-hour PM control device temperature
can be readily achieved in modern MWC's.
Comment: Three commenters (IV-D-24, IV-D-103, IV-D-108)
asserted that a 4-hour CO standard alone is insufficient to
ensure good combustion. One commenter (IV-D-24) suggested
that a 6 to 12 percent O2 standard be promulgated in addition
to the CO standard. One commenter (IV-D-108) stated that in
order to minimize products of incomplete combustion, shorter
term criteria for temperature and O2 should be specified. The
commenter noted that O2 and temperature are directly related
to combustion efficiency and are routinely monitored. This
commenter recommended that for MB/WW combustors, the EPA
should require that the exit flue gas meet a minimum 5-minute
O2 concentration of 3.5 percent on a wet basis and 3.0 percent
on a dry basis. The commenter noted that this recommendation
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was based on analysis of CEM data for three plants and with
the input of the plant operators.
Two commenters (IV-D-103, IV-D-108) also recommended that
minimum furnace temperature during waste combustion, after
overfire air, be specified. The commenters also suggested
requirements for controls such as automatic auxiliary burners
that will fire at preset temperatures to ensure that minimum
temperature is maintained at all times including startup and
when wet waste is being combusted. One commenter (IV-D-108)
contended that this minimizes emissions of combustible
pollutants, some of which are not continuously monitored, such
as dioxins/furans. The commenter (IV-D-108) recommended the
following limits for MB/WW combustors: a minimum 1-minute
average temperature of 1,500 °F for a 1 second residence time
after overfire air injection, with auxiliary burners
automatically fired at 1,550 to 1,600 °F. The commenter noted
that New Jersey has successfully implemented this requirement
for five operating MWC's. One commenter (IV-D-103)
recommended a residence time for combustion gas of at least 1
second at no less than 1,800 °F. This commenter (IV-D-103)
also recommended that control equipment for HC1 reduction must
be designed such that the flue gas temperature at the outlet
from the control device does not exceed 300 °F, unless a
demonstration is made that an equivalent collection of
condensible heavy metals and toxic organics can be achieved at
a higher outlet temperature or through the use of alternate
technologies.
Response: Good combustion practices were developed by
the EPA to minimize both formation and emission of
dioxins/furans and other trace organics. There are three
components to GCP: a CO emission limit, a load limit, and a
temperature at the inlet of the PM control device. All three
of these continuous compliance parameters have been shown to
correlate with either formation or emission of dioxins/furans.
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Low CO level is a surrogate parameter used to indicate
the operation at combustion conditions conducive to the
furnace destruction of trace organics. The load limit is used
to control excessive entrainment PM (PM carryover) which can
lead to formation of dioxins/furans downstream of the
combustor. The PM control device inlet temperature limit is
to limit formation of dioxins/furans on fly ash within the PM
control device by controlling formation rates. Peak formation
rates occur near 300 °C (570 °F) and decrease with decreasing
temperatures. Below about 225 to 250 °C (435-480 °F) the
formation rates are negligible. The temperature limit also
controls partitioning of dioxin/furan between the solid and
vapor phases. At lower temperatures, dioxins/furans remain
absorbed on PM and are disposed with the collected fly ash.
There is no evidence that dioxins/furans absorbed on fly ash
can be volatilized at ambient temperatures nor leached in
landfills.
The EPA spend a substantial amount of resources
investigating, developing, and documenting GCP. The EPA's
first effort resulted in a report on the combustion control of
organics (Municipal Waste Combustion Study: Combustion
Control of Organics, EPA/530-SW-87-021c, June 1987) . This
report on the control of organics contained tables summarizing
recommendations for good combustion practices to control
organic emissions from mass burn, RDF, and modular starved-air
MWC's. Recommendations were included for a combustion
temperature of 980 °C (1800 °F) at fully mixed conditions, a
50 ppm CO emission limit, a range of flue gas O2
concentrations for each combustor, the use of overfire air for
mixing, turndown restrictions, and the use of auxiliary fuel
to correct for low temperatures or high CO.
In reviewing these recommendations, it was decided that
only three parameters would be required to demonstrate
continuous compliance with GCP. These include a CO emission
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limit to insure operation at combustion conditions which are
indicative of the furnace destruction of organics, a load
limit which is to control the amounts of PM which are carried
out of the combustor with flue gases, and a temperature limit
at the inlet of each PM control device to control formation of
CDD/CDF within each control device.
Comment: Five commenters (IV-D-24, IV-D-28, IV-D-54,
IV-D-80, IV-D-95) supported the monitoring and control of APCD
inlet temperature. Three commenters (IV-D-28, IV-D-80,
IV-D-95) supported the proposed requirement of a maximum inlet
temperature, determined during the most recent dioxin/furan
test, which cannot be exceeded by more than 30 °F, but urged
the EPA to adopt a longer averaging period of 8 to 12 hours so
that reasonable variability does not result in an excursion.
One commenter (IV-D-24) maintained that a standard for
combustor flue gas temperature should be promulgated as part
of good combustion practices. The commenter (IV-D-24) pointed
out the importance of flue gas temperature based on the EPA's
1989 test program at the Montgomery Dayton South MWC. In a
detailed discussion, the commenter claimed that the study
showed that minor changes in design and operation had a
significant effect on emissions of dioxin and other
pollutants. The commenter (IV-D-24) acknowledged that some
vendors claim that lower temperatures cause corrosion and
operating problems, but argued that these problems can be
avoided by proper design and operation.
Response: The maximum PM control device inlet
temperature is selected by taking the highest average PM
control device inlet temperature measured during any one of
three successful performance test runs for dioxins/furans and
by adding 17 °C (30 °F). The averaging time for the PM
control device inlet temperature limit must be consistent with
the averaging time for a single dioxin/furan performance test
(approximately 4 hours). If an 8-hour averaging time was
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allowed for the inlet temperature, then a unit could
theoretically operate for 4 hours at temperatures above those
shown to be safe by the dioxin/furan performance tests.
The PM control device inlet temperature requirements help
ensure that conditions for high dioxin/furan formation rates
do not occur. The temperature at which low dioxin/furan
emissions is achieved may differ between MWC units, and the
requirements take that into account. Therefore, there is no
need for a specific flue gas temperature requirement.
Comment: One commenter (IV-D-24) supported EPA's efforts
to strengthen operator certification and training. The
commenter recommended the following six improvements to the
proposed requirements: (1) Limit the frequency and period of
time that control room operators can fill in for chief
facility operators and shift supervisors; (2) require that
recertification exams be passed every 5 years (on new
technologies and regulations); (3) to prevent the current
potential conflicts of interest, require that no employee of a
firm that has designed, operated, or constructed MWC's may
create or be permitted access to exam questions; (4) to
prevent future conflicts of interest, require that no employee
of a firm that has designed, operated, or constructed the
specific MWC at which an applicant is taking a site-specific
exam, be permitted to sit on the examining board; (5) require
applicants for operator certification to have either a
technical baccalaureate degree or 60 credits in physical
sciences and/or engineering at an accredited institution
instead of the current requirement of a high school diploma or
equivalent; and (6) require that the manual address in detail
the operating conditions, such as temperature, injection
rates, etc.
Response: The EPA appreciates the commenter's support
for operator training and certification. While the EPA
acknowledges the commenter's suggested revisions to the
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proposed requirements, they will not be incorporated into this
rulemaking at this time. The certification and training
requirements of the rule are adequate to assure that properly
trained personnel are operating the plants. Additional
prescriptive requirements would limit case-by-case flexibility
and are not necessary to ensure proper operation. States are
free to impose additional requirements if deemed necessary.
Additionally, the EPA can reevaluate these requirements in
subsequent reviews of the regulations.
Comment: Several commenters (IV-D-18, IV-D-28, IV-D-29,
IV-D-30, IV-D-43, IV-D-44, IV-D-51, IV-D-73, IV-D-74, IV-D-85,
IV-D-98, IV-D-103) agreed that operator certification and
training are appropriate requirements, but disagreed with the
timing, saying that the 6-month period is not adequate to
fully train and schedule testing and certification. Five
commenters (IV-D-51, IV-D-73, IV-D-74, IV-D-85, IV-D-103)
pointed out that certification could be required before the
end of 1995. The five commenters suggested that training and
testing sites in numerous locations in every State will be
required in order to offer all personnel sufficient
opportunity to obtain training and certification. Given the
number of operators that will now require training nationwide,
the commenters (IV-D-28, IV-D-29, IV-D-30, IV-D-43, IV-D-85)
urged the EPA to begin discussions with ASME to fully develop
the training program, and indicated that a phase-in period may
be needed. One commenter (IV-D-28) said the EPA should
consider whether other training organizations should also be
allowed to provide certification.
One commenter (IV-D-29) informed the EPA that applicants
are required to document 6 months of satisfactory employment
in the capacity of chief facility operator or shift supervisor
as a prerequisite for full operator ASME certification. This
commenter said the proposed rule is not clear whether an
operator would be permitted to work as a chief facility
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operator or shift supervisor during the period prior to
becoming eligible for full certification. This commenter also
pointed out that the site specific examination is conducted by
a three-member ASME board of examiners, including one
technical representative from the resource recovery industry
and one representative from the regulatory authority. The
commenter indicated that lead times of 6 months are often
necessary for the scheduling of exams.
Two commenters (IV-D-43, IV-D-44) suggested that a 2-year
period for certification is more reasonable given the current
state of the ASME certification program. One commenter
(IV-D-85) said that 3 years is more appropriate, and an
extension provision should be provided if delays result from
the hazards of developing a new certification process.
Response: The EPA has discussed the issue of
certification with ASME and agrees that the proposed schedule
is unrealistic given the limited ASME resources for testing
all those who require full certification. Because provisional
certification is required by ASME as the first step in
attaining full certification, the requirements are being
revised such that all chief facility operators and shift
supervisors have 1 year from promulgation or 6 months after
startup to become provisionally certified by ASME (or State-
approved equivalent). Also within the first year after
promulgation or 6 months after startup, all chief facility
operators and shift supervisors must complete or become
registered to take the ASME (or State-approved equivalent)
full certification exam. These changes will ensure that all
operators are, at a minimum, provisionally certified and are
scheduled to be fully certified as soon as can be accommodated
by ASME (or State-approved equivalent).
Comment: Five commenters (IV-D-51, IV-D-73, IV-D-74,
IV-D-98, IV-D-103) agreed that operator certification and
training are appropriate requirements, but requested that the
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sections be clarified. Four commenters (IV-D-51, IV-D-73,
IV-D-74, IV-D-103) requested guidance on what constitutes an
equivalent State certification program, how a State should
have its program reviewed for equivalency, and whether
equivalent certification is transferrable from State to State.
The current language is also not clear on whether the EPA is
assuming any training and certification responsibility other
than reviewing the equivalency of State programs. One
commenter (IV-D-98) said the EPA should clarify its assessment
of the ASME program so States that have already adopted it can
implement it without hesitation. This commenter said that
mandatory EPA training should not apply to individuals who
have already received ASME or State certification under
pre-existing State MWC rules by the time of NSPS promulgation.
Response: A State may develop and implement a program in
lieu of the ASME certification program. It is up to each
State to determine what constitutes an equivalent program.
ASME certification is transferrable from State to State in
accordance with ASME's guidelines. A State's certification is
only good within the State of issue.
If a chief facility operator, shift supervisor, or
control room operator has already received full ASME
certification by the time the NSPS and emission guidelines are
promulgated, the EPA operator training is not required.
Training based on the site-specific manual is still required.
Comment: Two commenters (IV-D-51, IV-D-74) said no
minimum criteria were provided for the mandated site-specific
manual, and if the EPA intends to use the criteria published
in the 1991 MWC standards, they should be incorporated into
this rule. These commenters also said it is not clear whether
State approval of the specific content of training manuals is
required, and warned that this would be burdensome to State
and local programs. The commenters asserted that the
preparation of a manual should be an enforceable part of the
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permit, but neither the States nor the EPA should specify what
the site-specific manual should contain, nor should the
contents be subject to State and public review and comment.
The commenters indicated that it would not be unreasonable to
require that plant operators certify that each affected
employee has been adequately trained using the manual. One
commenter (IV-D-73) said the manual and its updates should be
reviewed and approved by the State or local agency, but should
not be required as part of a permit application until after
the training and certification programs are in place.
Response: The contents of the site-specific manual will
not be subject to EPA review or approval; however, each plant
must develop a manual, make it readily available onsite, and
document that the appropriate personnel have been trained with
the manual. Twelve criteria for the manual were listed in the
proposed regulations under § 60.54b(d). States are free to
impose additional criteria or requirements for content review
as deemed necessary.
Comment: Five commenters (IV-D-30, IV-D-51, IV-D-73,
IV-D-74, IV-D-120) indicated that the training manual guidance
is not clear. One commenter (IV-D-30) questioned whether the
EPA has a training program or an official training manual.
The commenter said that a copy of the EPA manual was made
available to the ASME "SWPD" but was not generally available
for release. The commenter (IV-D-30) also expressed concern,
after reviewing the "Municipal Waste Combustor Operator
Training Program" (EPA-453/B-93-020), that EPA's program does
not meet the requirements of the ASME "QRO" certification
process and recommended several ways that it could be
modified.
Response: There are three separate training requirements
in this rule. The first is the ASME QRO-1 provisional and
full operator certification (or equivalent State
certification) for chief facility operators and shift
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supervisors. The second is the EPA municipal waste combustor
operator training program (or equivalent State training
course) for chief facility operators, shift supervisors, and
control room operators. The third is the training established
by each site to review the site-specific operating manual for
personnel including chief facility operators, shift
supervisors, control room operators, ash handlers, maintenance
personnel, and crane/load handlers.
The EPA operator training program was published in 1993
and has been distributed to ASME and the States as a model
program that States may adopt or use as a guide for their own
general training courses. Copies of the training program
manuals are available through National Technical Information
Services (NTIS). The EPA "Municipal Waste Combustor Operator
Training Program" (course manual EPA-453/B-93-020 and
instructor's guide EPA-453/B-93-021) is not intended to be
equivalent to ASME's QRO-1 certification. It is general
training in MWC operations for personnel responsible for
operating an MWC plant, and will help prepare personnel for
the ASME (or State-equivalent) certification.
Comment: One commenter (IV-D-85) said that operators of
incinerators without heat recovery would be at a severe
disadvantage and would have difficulty getting certified
because the current draft certification exam includes numerous
questions concerning safe operation of steam systems and
turbine generators. The commenter said ASME will need
additional time to develop questions specific to
incinerator-only plants.
Response: The ASME QRO-1 does not currently apply to
refractory type MWC's. Since the ASME does not currently have
a certification program for refractory type MWC's, the EPA did
not require operators of such MWC's to become certified. If
and when the ASME develops certification requirements for
refractory type MWC's, the EPA will consider them for
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incorporation into the MWC regulation. The EPA MWC operator
training program and training with the site-specific manual is
still required.
Comment: One commenter (IV-D-44) said it is not clear
why the EPA is requiring the establishment of O2/CO2
relationships at plants opting to correct emissions using CO2•
The commenter stated that the uses of these data, beyond
ensuring that an equitable O2/CO2 correlation standard exists,
could lead to future difficulties for MWC operators.
Response: Some plants may now be complying with State
emission regulations as referenced to 12 percent CO2• Most
likely, they will have a CO2 monitor and a computerized data
acquisition system which automatically report acid gas
emissions referenced to 12 percent CO2• Federal emission
limits are expressed in terms of 7 percent 02- To determine
compliance with the Federal emission limits, the plant must
determine the ratio of O2/CO2 to make corrections to plant
data that are expressed in terms of 12 percent CO2• During
performance testing for dioxins/furans and metals, the test
contractor should measure the flue gas concentration with a
continuous emission monitor (CEM) for 02- At proposal, the
plant was required to perform at least three runs at full load
and three runs at 50 percent load. This requirement has been
revised to a minimum of three runs at the typical operating
load of the unit. Comparisons between the plant CO2 CEM and
the test contractor's O2 monitor can then be made to establish
the ratio of CO2/O2 during the performance tests.
3.5.7 Size Categories for New Municipal Waste Combustor
Plants
Comment: Three commenters (IV-D-24, IV-D-65, IV-D-103)
disagreed with subcategorization based on size. One commenter
(IV-D-24) stated that the EPA has failed to explain why small
MWC plants have less strict standards than large MWC plants.
The commenter argued that there is no technological or legal
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basis for allowing small plants to have higher emissions than
large plants.
One commenter (IV-D-103) said standards based on size,
while reasonable for existing plants, do not seem appropriate
for proposed new plants. The commenter recommended that all
new plants regardless of size be subject to those requirements
currently proposed for large plants. Two commenters (IV-D-65,
IV-D-103) warned of the dangerous potential for proliferation
of small uncontrolled plants replacing existing plants,
resulting in an adverse impact on public health and the
environment. One commenter (IV-D-20) claimed that the EPA's
MWC data base has many small plants that do not perform well
because of low expectations by regulators and very lax
standards and permits which encourage plant design using
older, cheaper technology.
Response: The Act allows the EPA distinguish between
different groups of units by taking into consideration size
and costs. The final standards apply to MWC's at plants with
aggregate capacities greater than 35 Mg/day. The standards
subcategorize MWC's into small plants (35 to 250 Mg/day) and
large plants (greater than 250 Mg/day) based primarily on
combustion technology.
The EPA does not agree that a proliferation of
uncontrolled small plants will replace existing units. When
compared to existing plant guidelines, the new plant standards
that would apply to new small plants are more stringent for
all pollutants except Hg and NOx. All new plants with
aggregate capacities greater than 35 Mg/day will be required
to meet the NSPS.
MWC plants with capacities less than 35 Mg/day are not
being regulated under this rule; however, these plants are
currently being considered for regulation under section 129 of
the Act as part of the other solid waste incineration (OSWI)
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category (see 59 FR 66850). Refer to section 6.1 for further
discussion regarding the health impacts of dioxins/furans.
3.6 IMPACTS OF MUNICIPAL WASTE COMBUSTOR EMISSIONS STANDARDS
3.6.1 Environmental
Comment: Several commenters (IV-D-37, IV-D-38, IV-D-44,
IV-D-54, IV-D-64, IV-D-69, IV-D-80, IV-D-98, IV-D-127,
IV-D-128, IV-D-129, IV-D-130, IV-D-131, IV-D-132, VI-B-03,
VI-B-04) urged the EPA to consider the health and
environmental impact of replacing incineration of MSW with
other waste disposal options, such as landfilling, that they
claimed will result from implementation of the proposed NSPS
and guidelines.
Two commenters (IV-D-37, IV-D-38) explained that in
Florida, landfilling presents several adverse health and
environmental risks which are significantly greater than
continuing to rely on waste-to-energy. The commenters
mentioned Florida's high groundwater table, stating that the
groundwater is susceptible to contamination from landfills,
but is the principal source of potable water. The commenters
also mentioned the air emissions that are released from
landfills.
One commenter (IV-D-54) argued that the impacts on
groundwater, the cost of future cleanups, and the cost to
society for siting new landfills (as the only financially
viable alternative) should be calculated and considered.
Another commenter (IV-D-80) associated with an MWC plant in
Olmstead County, Minnesota explained that the County is
located over Karst geology, which is a type of formation that
is very susceptible to groundwater contamination. Another
commenter (IV-D-98) stated that landfills have recently been
recognized by EPA as major uncontrolled sources of HAP's,
having different and potentially more adverse effects on
neighboring communities and the global environment than MWC's.
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One commenter (VI-B-04) stated that environmental impacts are
being transferred from air to water.
One commenter (IV-D-44) explained that a number of health
risk studies have been performed that indicate that combustion
poses a lower health risk than other solid waste disposal
alternatives. The commenter provided the following two
articles by Kay H. Jones to demonstrate this point: (1) "Risk
Assessment: Comparing Compost and Incineration Alternatives,"
MSW Management, May/June 1991, and (2) "Comparing Air
Emissions from Landfills and WTE Plants," Solid Waste
Technologies, March/April 1994.
Response: "Flow control" is a term used to describe the
ordinances used by municipalities to mandate where the MSW
generated in their jurisdictions is to be disposed. It is
also used to describe State control of the transportation of
waste across State lines. Most MWC plants are constructed in
conjunction with flow control ordinances that require that MSW
from the surrounding communities be disposed of at the MWC
plant. These ordinances are to ensure that the MWC receives
enough MSW to operate and to generate the income required to
cover operational expenses and fulfill bond obligations.
Recently, however, flow control ordinances have been weakened
by a Supreme Court decision.
The EPA did not analyze the potential environmental,
health, and economic costs associated with alternative waste
disposal options (e.g., landfilling) because at the time of
the study, flow control was not an issue, and the EPA did not
incorporate changes in quantity of waste combusted into their
analysis. The increases in tipping fees estimated were not
based on the market effects of changes in quantities of waste
combusted and corresponding changes in price. Due to these
modeling assumptions, a shift in the use of municipal waste
combustion versus landfilling or other waste disposal option
was not estimated.
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Given that at the present time flow control is no longer
a realistic assumption and landfilling is a viable alternative
to combustion, various environmental, health, and economic
costs of landfilling may become relevant. However, any shifts
of MSW away from MWC's will generally result in MSW being sent
to uncontrolled alternatives. The EPA has examined the
relationship between flow control and human health (documented
in EPA's "Report to Congress on Flow Control and Municipal
Solid Waste," March 1995). The EPA finds that extensive and
stringent regulations are in place for landfills for the
purpose of protecting human health and the environment. For
example, the environmental impacts for landfills are addressed
through Subtitle D (i.e., all new landfills must have double
liners). The EPA has also proposed NSPS (40 CFR 60,
subpart WWW) and emission guidelines (40 CFR 60, subpart Cc)
for landfills under section 111 (b) and (d) of the Act to
control emissions of total nonmethane organic compounds from
landfills. Additionally, a landfills NESHAP is scheduled to
be developed by the year 2000. Thus, if the recent flow
control decision by the Supreme Court or the MWC regulations
by the EPA encourage more landfilling of MSW there seems no
reason to posit an increased health or environmental risks.
3.6.2 Cost and Economic
Comment: Four commenters (IV-D-18, IV-D-55, IV-D-85,
IV-D-98) contended that the EPA's costing analysis for the
NSPS and guidelines is outdated (i.e. is based on data
gathered for the economic impact analysis prepared for the
1989 proposed MWC NSPS and guidelines) and should be updated
to ensure its validity.
One commenter (IV-D-98) recommended that the EPA update
its economic analysis to take into consideration changes since
1989 in the following assumptions regarding "enterprise
costs": (1) Use of the average long-term bond yield as of
January 1988 to benchmark the public capital cost, and (2) a
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finding that costs to publicly-owned MWC's would be
appreciably lower than for private firms, based on differences
in what the EPA referred to as "the tax obligations and the
discount rates faced by public versus private entities." Two
commenters (IV-D-55, IV-D-98) added that the EPA should update
EPA's 1989 derivation of what it termed an "appropriate"
4 percent rate to determine the annual capital costs of
control equipment at publicly-owned MWC's. One commenter
(IV-D-55) reported that the financing rate for the Greater
Detroit Resource Recovery Authority, a large existing plant,
was 9.25 percent. One commenter (IV-D-98) concluded that
these outdated assumptions have resulted in a significant
underestimate of the costs of financing emission controls at
both new and existing MWC plants.
Response: The EPA conducted a sensitivity analysis to
see how the selected interest rate of 4 percent versus higher
interest rates for publicly-owned plants would effect the
EPA's selection of Regulatory Alternatives II-A or II-B. The
selected interest rate is meant to represent the "real" (i.e.,
inflation-free) cost of funds. To test the sensitivity of the
average annual enterprise costs to the interest rate, the EPA
recalculated the enterprise costs for public entities at
discount rates of 5, 7, and 10 percent (alternative interest
rates used for privately-owned plants) and compared these
costs to the enterprise costs calculated (prior to proposal)
using the 4 percent discount rate. As shown in table
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TABLE 3-1. MWC II/III EMISSION
GUIDELINES:
AVERAGE ANNUAL ENTERPRISE COSTS
FOR PUBLIC ENTITIES
Small MWC
Large MWC
plants
plants
(35 to 225 Mg
(over 225 Mg
MSW/day)
MSW/day
Regulatory
($1990/Mg
($1990/Mg
alternative
MSW)
MSW)
Interest Rate =
4 percent
Reg. Alt. I-A
16.32
20.24
Reg. Alt. II-A
33.65
20.24
Reg. Alt. I-B
16.32
20.25
Reg. Alt. II-B
33.65
20.25
Reg. Alt. Ill
46.02
17.21
Interest Rate =
5 percent
Reg. Alt. I-A
16.89
20.97
Reg. Alt. II-A
34.45
20.97
Reg. Alt. I-B
16.89
21.11
Reg. Alt. II-B
34.45
21.11
Reg. Alt. Ill
47.53
17.94
Interest Rate =
7 percent
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3-1, varying the interest rate to levels higher than
4 percent for public entities does result in higher potential
enterprise costs; however, the increase in estimated costs is
not large enough to affect the selection of regulatory
alternatives for the proposed or final regulation (i.e.,
Regulatory Alternative II-A or II-B).
Comment: Two commenters (IV-D-85, IV-D-98) contended
that the EPA is required to update its impact analysis for the
reasons discussed elsewhere in this section and to make the
updated analysis available to the public, as the basis for any
standards more stringent than the MACT floor.
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Response: The final standards for new sources are set at
the MACT floor for all pollutants; therefore, the EPA the
comment that the impact analysis must be updated as the basis
for any standard that is more stringent than the MACT floor is
not relevant.
Comment: Several commenters (IV-D-06, IV-D-08, IV-D-09,
IV-D-11, IV-D-28, IV-D-37, IV-D-38, IV-D-40, IV-D-41, IV-D-55,
IV-D-58, IV-D-62, IV-D-80, IV-D-84, IV-D-98, VI-B-02, VI-B-03,
VI-B-04, VI-B-05, VI-B-06) noted that the recent Supreme Court
decision (C&A Carbone, Inc v. Town of Clarkstown, New York
No. 92-1402) concerning waste flow control could have a
significant economic impact on the MWC industry, and urged the
EPA to consider the impacts in it's economic analysis for the
NSPS and guidelines. The commenters noted that without waste
flow control, the cost of the proposed emission guidelines and
NSPS would be very significant. Several commenters (IV-D-28,
IV-D-41, VI-B-04, VI-B-05, VI-B-06) maintained that many
political decision-makers are re-evaluating the use of MWC's
as their primary method of solid waste management, and that
several major facilities have announced their intention to
permanently close because the community can no longer
guarantee the source of solid waste supply to the MWC. Three
commenters (IV-D-28, IV-D-98, VI-B-04) predicted that the
proposed emission guidelines and NSPS, together with the two
Supreme Court decisions, would encourage the shift from the
use of MWC's to landfills.
Two commenters (IV-D-80, IV-D-98) mentioned the adverse
impact that the above changes would have on tipping fees. One
commenter (IV-D-80) explained that the EPA's estimate of the
average cost impact on small MWC plants of $35/ton MSW will
cause a 44-percent increase in tipping fees. The commenter
continued that this type of increase without flow control will
cause an economic crisis, causing their commercial haulers to
haul their County's MSW to landfills located out of their
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State without separation and processing. The commenter noted
that this crisis would result in their County's defaulting on
construction bonds, which would impact the County's bond
rating and would adversely affect all of the County's solid
waste facilities, including waste abatement, household
hazardous waste management, and recycling programs.
Response: A number of commenters raised issues related
to the EPA's assumption that there would be no change in waste
volumes or flows if MWC's raised tipping fees to cover the
costs of emissions control. The EPA made this assumption
because flow control was feasible when this regulation was
evaluated. The commenters argued that without flow control
municipalities can no longer guarantee a given quantity of MSW
for MWC's and that the problems raised by this removal of flow
control would be exacerbated by the proposed regulations.
Traditionally, many local and State governments have
controlled the ultimate disposition of MSW collected by
private companies through their use of "flow control" as well
as other mechanisms. Using flow control, governments dictate
where private waste collection firms within their jurisdiction
must take their MSW for processing, treatment, or disposal.
Thus, government can guarantee private companies who finance
the construction and operation of waste-to-energy and
materials recovery facilities a certain flow of waste. These
facilities cost several hundreds of millions of dollars to
construct. Revenue from the sale of the energy or recovered
materials and, more importantly, from tipping fees has been
applied to facility costs, a component of which would be debt
service on the facilities. The energy and recovered materials
are sold in markets and thus their prices are subject to the
discipline of competition. However, flow control confers a
monopoly on the facilities, allowing the establishment of
tipping fees in excess of costs. The profits earned can be
applied to cover the cost of other non-revenue bearing
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programs such as source reduction, curbside recycling,
household hazardous waste collection, education and outreach,
and, in some limited instances, even Superfund cleanups, that
comprise communities' ISWM programs. Flow control resulted in
increases in MSWM costs of 100 to 600 percent in some cases
(See "Municipal Solid Waste Management," September/October
1994, p.14).
In May 1994, the United States Supreme Court (in C & A
Carbone, Inc. v. Town of Clarkstown) ruled that flow control
is an unconstitutional impediment to interstate commerce
thereby obviating the monopoly position of the designated
facilities. This ruling makes MSW a commodity, subject to
market forces. While there are several bills in Congress to
restore this authority, to date, none have been passed.
Flow controls have been an important mechanism used to
guarantee waste flows to MWC's. In 1992, 58 percent of MWC
throughput was guaranteed by flow controls. Flow controls are
especially important for the larger facilities (see EPA's
"Report to Congress on Flow Control and Municipal Solid
Waste'" March 1995). In the absence of flow control, the
economic environment in which MWC owners must secure financing
has changed. Table
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TABLE 3-2. LANDFILL TIPPING FEES AT
SELECTED STATES
IN THE EASTERN U.S.
State
Average landfill tipping
fees ($/ton)
Connecticut
65
Maryland
43
Massachusetts
65
Minnesota
50
New Jersey
74
New York
62
Virginia
25
Source: BioCycle's 1993 Survey, as reported in
the EPA's "Report to Congress on Flow
Control and Municipal Solid Waste,"
March, 1995.
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3-2 shows the landfill tipping fees for selected eastern
states (see EPA's report to Congress). Table
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TABLE 3-3. AVERAGE COSTS OF WASTE-
TO-ENERGY TECHNOLOGIES
Average cost ($/ton)
Variable
Technology Fixed costs
costs*
Total
Mass burn 30
8
38
Modular 26
17
43
RDF 28
17
45
*Net of energy sales.
Source: As reported in the EPA's "Report to
Congress on Flow Control and
Municipal Solid Waste," March 1995.
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3-3 shows the fixed unit cost (debt service) and variable
unit cost of the three major categories of MSW combustor
technologies (i.e., mass burn, modular, and RDF). In a
competitive market framework MWC facilities would have to
charge tipping fees equal to those of landfills, after
accounting for any transport cost differences. To continue
operating, MWC's would have to cover their opportunity costs
(i.e., their variable costs.) The fixed costs are sunk, and
thus while covering them may be of consequence to owners and
debt holders they do not impact the viability of existing
facilities. For new facilities capital costs are an
opportunity cost and investors would have to anticipate
revenues sufficient to cover them before undertaking the
investment.
Given the large difference between the variable costs of
the MWC technologies and landfill tipping fees, it appears
that the costs of operating MWC facilities could rise fairly
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significantly before operators would elect to close them.
However, it is certainly conceivable that the loss of flow
controls plus the cost of meeting the requirements of the
regulation could make it difficult to cover debt service for
some operators.
Current ISWM programs were developed by local governments
in response to Federal mandates, State legislation, and
pressure from local citizens to reduce, recycle, combust, and
landfill, in that order of preference. The ISWM programs also
address the concern that new Federal landfill construction and
operation regulations will raise the cost of landfilling.
States frequently have required local governments to complete
complex MSW planning efforts, establish programs for dealing
with certain components of the waste stream, and achieve
mandatory recycling rates without providing funds to cover the
costs of these requirements. The result of the ISWM programs
has been a substantial increase in the recovery of recyclables
from MSW and a concurrent reduction in the demand for landfill
space. In 1993, the U.S. recovered 19 percent of MSW through
recycling and 3 percent of MSW through composting. Sixteen
percent of MSW was combusted, and 62 percent of MSW was
landfilled (see EPA's "Reusable News," Winter, 1995).
The success of ISWM in reducing the need for disposal
space and the development of large, low-cost landfills owned
by MSWM providers drove a wedge between tipping fees at waste-
to-energy and materials recovery facilities and landfill costs
encouraging private MSWM service providers to utilize
landfills. The recent Supreme Court decision has given
private haulers the right to ship their waste to the lowest
cost site no matter what location. This has put pressure on
municipalities to lower tipping fees at waste-to-energy and
materials recovery facilities to compete with landfills,
including out-of-State landfills using low cost long-distance
rail haul. Solid Waste Price Digest (November, 1992)
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estimates that the average landfill tipping fee is $28 per ton
of MSW versus $56 per ton of MSW at MWC facilities. Tipping
fee reductions for MWC's of as much as 50 percent have been
reported in the literature (MSW Management July/August 1994,
p.14). One of the side-effects of the Supreme Court decision
may be the default of some of the municipal revenue bonds used
to finance waste-to-energy and materials recovery facilities.
In its economic impacts analysis for the proposed and
final MWC regulations, the EPA has assumed that the additional
costs of operating MWC facilities to comply with the
regulations would not induce shifts in the disposal of MSW if
MWC's raised their tipping fees to cover these choices. In
the post-Supreme Court decision world, that assumption is less
tenable. The EPA finds that MWC costs are competitive with
landfilling costs in high-cost sections of the nation (e.g.,
northeast) but that MWC tipping fees are generally higher than
landfill tipping fees (see EPA's "Report to Congress on Flow
Control and Municipal Solid Waste'" March 1995).
As documented in the EPA's report to Congress on flow
control, the EPA has identified several ways that State and
local governments may accomplish some of the same outcomes as
flow control can produce. These include:
• government provision of collection services;
• contractor provision of collection services under
government contract;
• franchising collection and hauling to designated
facilities;
• subsidizing facilities from the general revenues;
and
• supporting ISWM programs from the general revenue.
Thus, government can guarantee a continued source of MSW for
MWC's, and they can provide funds to support the operation of
these facilities from the general revenue. However, what flow
control provided was a mechanism for obtaining funding
directly from waste generators, especially commercial
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establishments. Without flow control, governments must raise
taxes or displace other programs to subsidize MWC's and ISWM
programs.
In summary, the EPA finds that if MWC's raise tipping
fees to cover the costs of the regulations, then the likely
result will be to encourage the shift of some wastes to other
disposal options. The specific impacts are likely to be very
place-specific, depending on the relative tipping fees of
MWC's and other disposal options, transportation costs and
institutional factors. If tipping fees are not raised, then
operators of MWC's will have to finance the costs of the
regulations out of current revenues.
Comment: Several commenters (IV-D-28, IV-D-41, IV-D-55,
IV-D-84, IV-D-98) noted that the recent Supreme Court decision
regarding ash management (the city of Chicago v. Environmental
Defense Fund No. 92-1639) concerning ash management could have
a significant economic impact on the MWC industry, and urged
the EPA to consider the impacts in its economic impacts
analysis for the NSPS and guidelines.
Response: The draft Federal policy on ash management
referred to by the commenters has changed. The final Federal
policy on ash management allows MWC's to combine bottom ash
and other ash for the purpose of preparing an ash sample to
test for toxicity. This final policy replaces the earlier
draft policy requiring that the sample be prepared with only
bottom ash, which is the most toxic ash produced by MWC's.
Due to this decision, the impacts of the final ash management
Supreme Court decision are not expected to be significant.
3.7 SELECTION OF FORMAT OF PROPOSED STANDARDS FOR MUNICIPAL
WASTE COMBUSTOR EMISSIONS
Comment: Several commenters (IV-D-18, IV-D-28, IV-D-34,
IV-D-43, IV-D-44, IV-D-54, IV-D-55, IV-D-56, IV-D-67, IV-D-80,
IV-D-85, IV-D-98, IV-D-99, IV-D-108, IV-D-120, VI-B-02,
VI-B-05, VI-B-06) supported an alternative percent reduction
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option for various pollutants and urged the EPA to retain the
efficiency provisions in the final rule. Several commenters
(IV-D-18, IV-D-28, IV-D-43, IV-D-44, IV-D-54, IV-D-56,
IV-D-67, IV-D-80, IV-D-85, IV-D-98, IV-D-108) supported
the percent reduction option for HC1 and SO2• Several
commenters (IV-D-18, IV-D-43, IV-D-44, IV-D-54, IV-D-85,
IV-D-98, IV-D-108, IV-D-120) supported a percent reduction
alternative for Hg. One commenter (IV-D-54) suggested that
the option be added to the N0X standard. Two commenters
(IV-D-34, IV-D-98) recommended that the option be added to the
Cd and Pb standards.
One commenter (IV-D-28) noted that the earlier proposed
emission guidelines and NSPS were proposed with only a
numerical limitation, but changed at promulgation to include a
percent reduction option. Comments and data were submitted
during that comment period to the EPA supporting the change
for acid gases because many units had already installed SD's
that were based on percent reduction.
One commenter (IV-D-24) criticized the 85-percent
reduction option for Hg and urged that this option be
eliminated. The commenter contended that the percent
reduction option would allow sources to emit pollutants at
levels above the numerical level that is the MACT floor. The
commenter contended that a percent reduction will discourage
operational optimization and waste separation.
Several commenters (IV-D-18, IV-D-43, IV-D-54, IV-D-55,
IV-D-56, IV-D-80, IV-D-85, IV-D-98, IV-D-99, IV-D-108) cited
the variable nature of the incoming waste stream as support
for a percent reduction option. The first commenter (IV-D-18)
cited the fact that the control devices are only capable of
achieving a certain maximum removal efficiency and that, other
than properly operating an MWC unit and its control equipment,
an operator can do nothing more to control certain emissions
such as Hg, SO2, and HC1 and is subject to the variability in
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the incoming MSW. This commenter argued, that to meet the
numerical limit during times of high inlet concentrations, the
control equipment would have to be operated at extremely high
removal efficiencies that may be beyond the capabilities of
the systems.
Response: As determined during the 1991 promulgation,
the EPA agrees that percent reduction options are necessary
for HC1 and SO2 due to the inherent variability in the waste
stream and the limitations of the control devices to a maximum
level of reduction. The EPA also agrees that the percent
reduction option is appropriate for Hg for the same reasons.
The percent reduction option ensures that a well-operated unit
with a well-operated control device is not penalized if a
numerical emission limit is beyond the control capability of
the control device during periods of unusually high inlet
concentrations. The EPA does not agree that this option will
discourage operational optimization. The EPA does not have
data indicating that percent reduction options are necessary
for N0X, Pb, or Cd.
Comment: Several commenters (IV-D-28, IV-D-41, IV-D-49,
IV-D-56, IV-D-7 3, IV-D-98, IV-D-104, IV-D-120, VI-B-02,
VI-B-05, VI-B-06) discussed the use of total mass versus TEQ
for dioxin furan emissions. Several commenters (IV-D-28,
IV-D-73, IV-D-120, VI-B-02, VI-B-05, VI-B-06) urged the EPA to
use a total mass emission rate instead of TEQ or a dual
standard for dioxin/furan emissions. Several commenters
(IV-D-28, IV-D-98, VI-B-02, VI-B-05, VI-B-06) informed the EPA
that based on the commenters' analysis of dioxin data, the
ratio of total mass to TEQ varies dramatically from plant to
plant, ranging from 20 to 1 up to 100 to 1. One commenter
(IV-D-73) said total mass is an appropriate and more
straightforward approach as discussed in the comment summary
BID for the 1991 rule. The commenter also pointed out that
the Act does not require the use of TEQ's.
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One commenter (IV-D-56) indicated that a standard based
on TEQ is flawed because the EPA has never offered a
technically convincing discussion of the relationship between
total mass and TEQ.
One commenter (IV-D-120) said that it is difficult to
compare dioxin/furan emissions between plants based on TEQ's.
This commenter noted that combustor design and operators are
only able to reduce the toxicity of a plant's emissions by
controlling total amount released, and cannot manipulate the
mixture of dioxins/furans. The commenter recommended that
plants still continue to report the breakdown of emissions so
that a TEQ can be determined. Two commenters (IV-D-73,
IV-D-120) pointed out that the further refinements in the
TEF's are expected.
Two commenters (IV-D-49, IV-D-104) urged the EPA to use a
TEQ basis rather than a total mass emission rate basis for
dioxin/furan emissions. The commenter stated that the TEQ
basis provides a more meaningful and appropriate assessment of
the emissions since it takes into account the toxicity of the
various congeners. The commenter said many States and
countries use a TEQ basis and this approach would simplify
comparisons and create uniformity.
Response: Based on the response of the commenters and a
review of the EPA's data, the EPA is promulgating the
dioxin/furan standards and guidelines in terms of total mass.
The EPA's emissions data base is in terms of total mass, and
support of a standard in terms of TEQ's would require a
recompilation of the data bases using TEQ data. In addition,
the dual format appeared confusing to commenters.
3.8 PERFORMANCE TEST METHODS AND MONITORING REQUIREMENTS FOR
MUNICIPAL WASTE COMBUSTOR EMISSIONS
3.8.1 Periodic Testing
Comment: Several commenters (IV-D-18, IV-D-28, IV-D-34,
IV-D-43, IV-D-44, IV-D-55, IV-D-65, IV-D-69, IV-D-75, IV-D-80,
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IV-D-85, IV-D-90, IV-D-98) suggested that performance testing
not be required of all identical units at a particular site
every year. One commenter (IV-D-99) supported the annual
stack test requirement for large MWC's. Four commenters
(IV-D-28, IV-D-80, IV-D-90, IV-D-98) supported periodic stack
testing for parameters not continuously monitored, but said
that annual testing is excessive.
Three commenters (IV-D-18, IV-D-75, IV-D-80) suggested
that annual performance testing on only one of the identical
MWC units at the same site should be allowed if the
performance tests from the previous year demonstrated that all
requirements were achieved by all the identical units. Two
commenters (IV-D-18, IV-D-75) said in the event that any
emission parameter was not adequately demonstrated, that
parameter should be tested on all units the next year.
Several commenters (IV-D-43, IV-D-44, IV-D-85, IV-D-98)
recommended that, once initial compliance is demonstrated,
annual stack testing be rotated among identical units at a
plant. Overall compliance would be demonstrated through
similarities in CEM data from the units not subject to the
full stack test. One commenter (IV-D-28) urged the EPA to
revisit the requirements in light of the financial
considerations involved for local governments and the
duplication of data. Six commenters (IV-D-44, IV-D-55,
IV-D-69, IV-D-85, IV-D-95, IV-D-104) said that annual testing
is unnecessary and will place an unreasonable burden on plant
owners and operators. One commenter (IV-D-85) said testing
rotation has been successfully applied by State agencies such
as in Massachusetts.
Response: The EPA has considered the commenters'
suggestions for reduced periodic testing requirements for
large combustors, and is promulgating an alternative schedule
for dioxin/furan testing, the most costly of the tests
required by this rule. The Administrator considers
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dioxin/furan emissions as important pollutants to reduce, and
is providing the incentive of less frequent testing in
exchange for lower dioxin/furan emissions. The incentive
emission levels are as follows: 7 ng/dscm for all new plants;
15 ng/dscm for large existing plants; and, 30 ng/dscm for
small existing plants. Any plant at which all MWC units
achieve levels below the incentive level for two consecutive
years may, thereafter, alternate testing between the units at
the site. The plant may test one unit per year so long as
each unit tested emits dioxins/furans below the incentive
level. If an annual test indicates that a unit's dioxin/furan
emissions are above the incentive level, then, beginning the
subsequent year, the plant must revert to testing all units at
that site annually until all annual performance tests over a
2-year period indicate that all units are achieving the
dioxin/furan emission incentive levels.
For dioxin/furan emissions, small plants may comply with
either the incentive limit schedule described above or the
proposed schedule which allows small plants to test every
third year once the MACT emission limits have been achieved
for three consecutive years.
Comment: Five commenters (IV-D-18, IV-D-44, IV-D-54,
IV-D-80, IV-D-98) recommended that the EPA delete the
requirement for the annual opacity test using a certified
observer. The commenters indicated that the requirement is
redundant and is a poor substitute for a calibrated COM. The
commenters said this will result in additional testing expense
without perceptible benefit.
One commenter (IV-D-98) said that 40 CFR § 60.11(e) (5)
expressly allows use of COM data in place of Method 9 under
any NSPS or guideline which contains a Method 9 testing
requirement.
One commenter (IV-D-18) said the required COM's are
reliable devices and should be accepted for demonstration of
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compliance just as CEM's are accepted by the EPA for SO2
emissions without the additional requirement of an annual
stack test. Secondly, this commenter contended that there is
not a direct correlation between what the opacity monitor
reads and what the visible emissions observer reads. The
commenter maintained that this is an apples and oranges
comparison.
Response: The proposed standards and guidelines were
based on stack tests using Method 9; therefore, the standards
and guidelines will be promulgated based on periodic Method 9
stack tests. The annual stack test can be waived under the
general provisions. The COMS is used as an indicator to
initiate corrective actions or a retest of the MWC.
3.8.2 Continuous Monitoring
Comment: Two commenters (IV-D-24, IV-D-32) indicated
that CEM's for HC1 have been used extensively, both here and
abroad. One commenter (IV-D-24) stated that Pennsylvania
requires HC1 CEM's for plants built after 1986, and that
Westinghouse installed nine CEM's at the York and Delaware
County MWC's. This commenter also contended that SO2 cannot
be used as a surrogate for HC1 because sulfur varies
independently of the chlorine content in the waste stream.
The commenter did not submit data to support this statement.
The other commenter (IV-D-32) said that Pennsylvania,
Maryland, and New Jersey require HC1 CEM's on new units.
Response: The EPA's current data indicate that HC1 is
preferentially removed and that high levels of SO2 removal
indicate high levels of HC1 removal. Therefore, the SO2 CEMS
being required will provide an indication of HC1 control.
Based on the comments received, HC1 CEMS will be available in
the future. When available, the EPA will publish appendix B
procedures for HC1 and require HC1 CEMS where appropriate.
The standards for HC1 are promulgated as proposed with
compliance based on annual HC1 stack tests.
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Comment: Two commenters (IV-D-14, IV-D-15) provided
information regarding their CEMS for HC1 emissions in response
to the EPA's request for availability, accuracy, precision,
and cost data. One commenter's (IV-D-14) device measures HC1
concentration through infrared spectroscopy. In addition to
HC1, this device can also measure SO2, N0X, CO, CO2, O2, NH3,
and H2O, simultaneously. This system is available and is
being used in the United States (at least six MWC plants are
listed by name). The system has been approved for HC1
monitoring by New Jersey and Pennsylvania. The commenter
claimed that the monitors are reliable and obtain valid data
for about 95 percent of plant operating time. Detailed
descriptions of the device's design and operation and
maintenance procedures are also included with the comment.
The commenter stated that the cost of a CEM system to monitor
N0X, SO2, and CO is about $75,000, and the cost to add HC1 and
H2O capabilities is about $37,000, for a total cost of
$112,000. These costs do not include an optional data
acquisition and reporting system.
In another commenter's (IV-D-15) device, the HC1
concentration is measured through a solid state sensor,
similar to the zircon dioxide sensor for O2, except a solid
silver ionic conductor is used. A more detailed description
of the device's design is included with the comment. This
system is expected to be available for sale in 1995. The
commenter expects the cost of this HC1 CEM system to be
$30,000 to $40,000.
Response: The EPA appreciates the information submitted
by the commenters regarding their HC1 CEMS. However, as
discussed above, the EPA has not published appendix B
procedures for HC1. Once the EPA publishes appendix B
procedures for HC1, the EPA will require HC1 CEMS where
appropriate. Refer to the previous comment for additional
discussion of HC1 CEMS.
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Comment: One commenter (IV-D-14) provided information
regarding their CEM for Hg emissions in response to EPA's
request for availability, accuracy, precision, and cost data.
The commenter's device measures Hg concentration through "Cold
Vapor Atomic Absorption Spectroscopy after conversion of ionic
Hg into the elemental Hg". A description of the device's
design is included with the comment. The device is expected
to be available for sale mid-1995. The cost is estimated to
be $70,000 for a stand-alone system, and $55,000 for a system
added on to an existing CEM system for NOx, SO2, CO, and HC1.
Response: The EPA appreciates the information submitted
by the commenter regarding the Hg CEMS. While CEMS do exist
for Hg, their performance history is not documented. Hg
monitors continue to be evaluated by the EPA. There is no
requirement for Hg CEMS in this rulemaking; however, States
are free to impose such requirements if they choose.
Comment: One commenter (IV-D-24) stated that the final
rule should require installation of CEM's for Hg or, if it
does not, should state that the EPA believes that variability
of Hg emissions is so slight that CEMS are unnecessary. The
commenter described two technologies that have been developed
and used. The first, called OPSIS Differential Optical
Absorption Spectroscopy, was tested on the Hogdalen plant in
Sweden in 1988, was found to be in agreement with the
permanganate analysis technique, and was approved for used by
the German government. The second, reported at EPA's 1991 MWC
conference, continuously measured elemental and chloride forms
of Hg by converting the chloride form to the elemental form by
exposing it to condensate of the reducing agents existing in
the flue gas.
Response: The Agency believes that there will be short
term variability of Hg emissions on occasion due to
variability in the incoming waste stream. However, the
performance history of Hg CEMS is not currently well-
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documented and there is no requirement for Hg CEMS in this
rulemaking. States are free to impose such requirements if
they choose. Monitoring of the carbon injection feed rates,
as applicable, will help to ensure that Hg reductions are
achieved on a continuous basis.
Comment: One commenter (IV-D-20) urged the EPA to
provide an alternative means of opacity compliance for units
employing wet scrubbing systems, which have water-saturated
plumes. The commenter claimed that at units with saturated
stack gases, the moisture will interfere with the opacity
measuring device.
The commenter informed the EPA that the unit described
currently uses surrogate measurements that are outlined in
both its air and RCRA permits to comply with opacity and PM
requirements. The commenter suggested the following
alternatives for units with ionizing wet scrubbers: ash feed
rate, scrubber flow rates, or operational status of ionizing
units. Pressure drop was the suggested alternative for units
with venturi scrubbers.
Response: The commenter may petition the Administrator
under the general provisions, § 60.13, for alternative means
of measuring opacity.
Comment: One commenter (IV-D-98) said the proposed
requirement for simultaneous availability of paired data for
monitored pollutants and diluent gas, over 75 percent of the
operating hours in 90 percent of the operating days per
quarter, is an unreasonably burdensome increase over the
requirements in subpart Ea, and is not necessary. The
commenter recommended that the EPA allow data to be available
for the specified minimum percentages of operating hours on an
independent basis.
Response: The intent of the 75-percent and 90-percent
data availability requirements is to ensure that an acceptable
minimum amount of data are collected and to prevent prolonged
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periods of operation without a working CEM. Available data
support these levels of availability. The EPA has revised the
regulatory language to clarify that each pollutant data point
is not required to be measured simultaneously with an oxygen
data point. The regulation requires, however, that each
pollutant hourly average be corrected by an hourly average
oxygen value (i.e., data are "paired" on an hourly basis).
Comment: Several commenters (IV-D-28, IV-D-44, IV-D-54,
IV-D-80) described concerns regarding the ability of CEMS to
meet the required level of performance. One commenter
(IV-D-44) noted that, while most instruments on the market are
capable of meeting the 75-percent/90-percent availability
requirement, plants frequently experience difficulties with
other system components including probes, filters, sample
lines, and conditioning systems which can and do impact system
availability. The commenter requested that the EPA
investigate the performance data used as the basis for this
requirement to ensure that the data used represent the
availability of the complete systems at a variety of locations
on an MWC unit. Two commenters (IV-D-28, IV-D-80) urged a 3
to 5 year phased approach to the 90-percent CEM availability
requirement.
Response: The EPA is confident that the 75-percent/
90-percent data availability requirement is reasonable and
achievable for the current level of CEMS technology. The data
used to determine the quarterly achievable level of
availability for CO, N0X, opacity, and SO2 CEMS were gathered
from numerous quarterly compliance reports for four MWC plants
during 1990 through 1993. The lowest minimum quarterly data
availability achieved was 90 percent. Since 75-percent
quarterly data availability has been required since the 1991
promulgation, and data show that 90 percent availability
currently being achieved, there is no need to phase in this
increased requirement.
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Comment: One commenter (IV-D-74) recommended that the
EPA incorporate into the final rule CEM requirements developed
by NESCAUM. At a minimum, the commenter requested that the
EPA require 90 percent data availability for gas monitors and
95 percent data availability for opacity monitors. The
commenter attached a copy of the 1990 document titled "NESCAUM
Recommendations on CEMS Performance and Quality Assurance
Requirements for MWC Facilities".
Response: The EPA is confident that the 75-percent/
90-percent data availability requirement is reasonable and
achievable for the current level of CEMS technology. The data
described in the previous response indicate that 90-percent
quarterly data availability for opacity is achievable.
Comment: One commenter (IV-D-80) requested clarification
of the terminology used in the proposal which refers to
"paired CEMS hourly averages". The commenter assumed it means
that pollutant concentrations must be corrected to standard O2
or CO2 concentrations.
Response: The commenter is correct. Calculation of the
24-hour geometric daily averages for SO2, 24-hour arithmetic
daily averages for NOx and CO (as applicable), and 4-hour
arithmetic daily averages for CO (as applicable) requires the
use of hourly CEM data that has been corrected for O2 (or
carbon dioxide). The regulatory language has been revised to
clearly specify that the data must be corrected for O2 (or
carbon dioxide) on an hourly basis. More frequent diluent
corrections are not required but are acceptable.
3.8.3 Proposed Test Methods
Comment: One commenter (IV-D-20) requested that
Method 6020 (ICP-MS) be included as an acceptable method to
use for metals analysis. The commenter was not certain if
Method 6020 is a final SW-846 method yet, but stated that this
method is suitable for metals.
Response: The commenter is correct, and analysis of
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Method 29 samples by ICP-MS is acceptable. Method 29 will be
amended accordingly.
Comment: One commenter (IV-D-120) requested that, while
the EPA has not proposed revising Method 23, it should
consider allowing the combination of the toluene rinsate of
the sampling apparatus (required by Method 23, section 4.2.4)
with the remaining combined sample, rather than analyzing this
rinsate separately (required in Method 23, section 5.1.6).
The commenter informed the EPA that plant operators in
Minnesota have combined the toluene with the remaining sample
for the cost savings, even when this potentially results in
higher overall dioxin/furan emissions in comparison to the
federal emission limits. The commenter also pointed out that,
most importantly, not including the results allows a plant
with high dioxin/furan concentrations in the toluene rinsate
to continue to emit an unregulated source of dioxin/furans,
contrary to the purpose of the standards.
Response: The EPA proposed a revision of EPA Reference
Method 23 on May 31, 1995 (60 FR 28378) . The proposed
revision includes the elimination of one rinsing and analysis
step. For a more complete response to the issues raised by
the commenter and additional information on this method, refer
to docket No. A-94-22 and the EPA Technology Transfer Network
(TTN) bulletin board.
Comment: Two commenters (IV-D-44, IV-D-98) questioned
whether the proposed test methods have been validated. One
commenter (IV-D-98) said that the EPA has not completed its
general validation of test methods referenced in both the 1989
and current rulemakings with respect to MWC flue gases, nor
has the EPA commenced any validation of these test method at
the levels of compliance required by these proposals. The
commenter said such validations are required by 40 CFR 60,
appendix A (Test Methods) and by section 129(c)(3) of the Act.
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One commenter (IV-D-44) asked whether Method 29, (for
measuring Cd, Pb, and Hg) has been validated on MWC's and, if
so, where can the documentation be found? The commenter
asserted that the proposed Reference Method has evolved from
methods intended for quantifying emissions from sources other
than MWC's, such as hazardous waste disposal processes. The
commenter's understanding is that the EPA standard procedures
require that methods be validated for use on targeted source
categories before they can be specified as the compliance
method.
Response: The EPA believes that all of the methods
specified for determining compliance with subpart Eb are valid
for use on municipal waste combustors (MWC's). The docket
contains several reports that deal with method validation
studies conducted on these methods on MWC's and similar
sources. Furthermore, each of these methods was used to
collect the data from MWC's that is used to support the
standard in subpart Eb. During the course of this data
collection, each of the methods performed in an acceptable
manner and met the respective quality assurance limits
required by each method. Multiple samples were collected from
each MWC using each method. Standard deviations calculated
for each method using these data meet expectations for
measurements of this type. The same can also be said of these
values, even if they are calculated to include the variability
associated with the source, as well as the variability of the
method. It is therefore EPA's judgement that these methods
are appropriate for performance test methods, and are
considered validated methods for MWC's.
3.9 REPORTING AND RECORDKEEPING REQUIREMENTS FOR MUNICIPAL
WASTE COMBUSTOR EMISSIONS
Comment: Five commenters (IV-D-18, IV-D-24, IV-D-55,
IV-D-85, IV-D-108, IV-D-120) requested that the monitoring and
recordkeeping requirements for carbon injection rates be
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further defined. Two commenters (IV-D-18, IV-D-85) said it is
unclear if carbon usage should be tied to waste feed rate,
boiler steam load, or some other parameter, and that the
averaging time is also unspecified. Two commenters (IV-D-24,
IV-D-108) recommended that the EPA require plants to conduct
tests to determine optimal reagent injection rates. Two
commenters (IV-D-18, IV-D-85) suggested that a plant-specific
minimum carbon injection rate be established based on the
steaming rate, which is already required to be measured and
controlled to no more than 10-percent greater flow than that
measured during the dioxin/furan performance testing. One
commenter (IV-D-18) reasoned that plants may try to vary the
carbon injection rate with the steam rate or the waste feed
rate due to the high cost of carbon. This commenter also said
a carbon usage rate based on pounds of carbon per 1,000 pounds
of steam for the plant has been adopted by the Florida DEP in
their MWC rulemaking for Hg emissions. Commenter (IV-D-18)
also suggested that a daily average carbon injection rate be
used for dioxin/furan control.
Two commenters (IV-D-18, IV-D-85) suggested monitoring
carbon usage on a weekly basis. One commenter (IV-D-18) said
that this was the basis used by the Florida DEP in their MWC
rulemaking for Hg emissions. Two commenters (IV-D-18,
IV-D-85) stated that the EPA has not demonstrated that
recordkeeping and reporting on an 8-hour basis is possible,
accurate, or necessary. The commenters indicated that
measurement of carbon usage from a silo or bulk bag would be
difficult except by tracking the quantity and frequency of
activated carbon deliveries, which may only occur weekly. One
commenter (IV-D-24) said operators should be required to
adhere to the optimized carbon and alkaline reagent injection
rates at all times and provide authorities with records
verifying regular purchase of each reagent consistent with the
optimal usage rates. A second commenter (IV-D-108) cited the
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New Jersey regulations and said that the State requires
optimization of the Hg APCD's with reasonable reagent use and
then requires monitoring of the minimum reagent injection
ratio to ensure that the control efficiency is maintained,
since Hg cannot be measured continuously. The commenter
attached a copy of the New Jersey adoption document for the
State rule (NJAC 7:27-27) adopted September 23, 1994. One
commenter (IV-D-102) argued that owners/operators of new and
existing sources should be required to keep records of
activated carbon use for each 1-hour period because the EPA
field test data on the effectiveness of activated carbon are
generally based on short term carbon injection rates.
Response: The EPA has clarified the monitoring and
recordkeeping requirements as follows. The carbon injection
rate requirement is not being directly tied to waste feed rate
or steam load. Plants are required to monitor the settings of
the carbon feed system during the performance tests for Hg and
dioxins/furans. An hourly carbon feed rate shall be estimated
from carbon feed system operating parameters such as screw
feeder speed, hopper fill frequency, hopper volume, or other
parameters or a combination of parameters, as appropriate to
the feed system.
Once dioxin/furan and Hg compliance has been established,
the carbon feed system must be operated such that the carbon
feed system parameter (or a combination of other parameters)
that is the primary indicator of the carbon feed rate must
equal or exceed the level determined during the most recent
performance test. For example, if screw feeder speed was
determined to be the primary indicator of carbon feed rate,
the screw feeder must be operated at a speed equal to or
greater than the speed measured during the performance test.
This is to ensure that an equal or greater carbon feed rate
than that determined during the performance test is maintained
at all times.
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Once a carbon injection rate for control of
dioxins/furans and Hg is determined during a performance test,
the unit must operate at the same or a greater rate of carbon
injection until the subsequent performance test. Any plant
wishing to use a lower feed rate must perform a performance
test demonstrating that the lower rate will achieve compliance
with both pollutant emission limits.
In addition to monitoring the carbon feed system
parameters, an hourly carbon feed rate must be estimated for
each hour of operation for each unit and used to estimate the
amount of carbon consumed during each calendar quarter by the
MWC plant. This estimate should be approximately equal to the
amount of carbon delivered to the plant each quarter.
3.10 STARTUP, SHUTDOWN, AND MALFUNCTION PROVISIONS
Comment: Three commenters (IV-D-24, IV-D-74, IV-D-103)
argued that the NSPS and emission guidelines should require
compliance with applicable emission limitations during
startup, shutdown, and "upsets". The commenters reasoned that
when auxiliary burners and APC equipment are operated
properly, there is no need to excuse compliance during startup
or shutdown. One commenter (IV-D-24) suggested that the final
rule should require reporting of data needed to determine
compliance at all times including startups and shutdowns. The
commenter stated that the auxiliary burner located in the
furnace should be used to bring the temperature in the furnace
up to 1,800 °C prior to charging wastes and should be used to
maintain the temperature across the furnace at 1,800 oc until
the last bit of waste has passed through the combustor. Two
commenters (IV-D-24, IV-D-74) also stated that upset
conditions reflect a failure to observe good operating
practice or maintenance. The two commenters suggested that if
upset conditions cause a failure to meet emission limitations,
they should result in a violation.
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Response: As there is always the chance for
uncontrollable instability during startup and shutdown, these
periods are not representative operating periods and are not
subject to the operational standards listed in this rule.
These periods are limited to 3 hours. After 3 hours, data are
used for compliance determinations.
Malfunctions are considered unavoidable and, therefore,
are not considered violations. Malfunctions are also not
subject to the operational standards listed in this rule.
However, failures that are avoidable are not malfunctions and
are subject to the operational standards. According to the
general provisions in subpart A of 40 CFR 60, "Malfunction
means any sudden, infrequent, and not reasonably preventable
failure ... Failures that are caused in part by poor
maintenance or careless operation are not malfunctions."
Thus, if a failure occurs that is reasonably preventable, it
could result in a violation if the operational standards are
not achieved during the failure. The final startup, shutdown,
and malfunction provisions have not been changed from those
that were proposed.
Comment: Two commenters (IV-D-74, IV-D-103) pointed out
that automatic waste cutoff measures should be included in the
incinerator design to shut off the waste feed whenever
critical operating parameters have been violated.
Response: While automatic waste cutoff measures are not
required by the NSPS, such equipment could be used and could
be considered by State agencies. The combination of emission
limits, performance tests, and continuous monitoring of
emissions and operating parameters that are specified in the
standards were judged adequate to ensure combustors and
control systems will be well designed, operated, and
maintained and continuous emission reductions will be
achieved. An equipment specification such as that described
by the commenters is not necessary to ensure control.
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Comment: One commenter (IV-D-103) stated that it is not
appropriate to apportion a generic 3-hour time period for
correction of malfunctions since different time periods may be
required to rectify different problems.
Response: The 3-hour time period is useful and
appropriate for correction of malfunctions. The General
Provisions, and most rules, do not provide any time limit for
malfunctions. To avoid a violation in these cases, the
owner/operator has to demonstrate that it is a malfunction and
that they have acted to minimize emissions and correct the
malfunction as soon as practicable. In this rule, up to
3 hours worth of data may be dismissed during a malfunction
period. If the malfunction is not corrected after 3 hours,
the owner/operator can either shutdown the unit or plan to
offset any emissions that are in non-compliance. As it is
useful to have a time period and no data have been provided to
support a longer or shorter time period, no change has been
made to the regulation as proposed.
Comment: One commenter (IV-D-72) suggested that the CO
standard in the NSPS and emission guidelines of 100 ppmv at a
4-hour interval should have a provision for startup, shutdown,
or upset conditions. The commenter agreed that the levels are
reasonable and achievable under steady-state conditions at the
commenter's FBC, but the commenter stressed these levels are
impossible to achieve under startup, shutdown, or upset
conditions.
Response: The standards have a provision for startup,
shutdown, or malfunction that applies to all the regulated
pollutants. According to proposed § 60.58b(a)(1), "... the
standards under this subpart apply at all times, except during
periods of startup, shutdown, or malfunction. Duration of
startup, shutdown, or malfunction periods are limited to 3
hours per occurrence." Note that the 3-hour clock does not
start until waste is on the grate. After 3 hours, data must
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be included for compliance determinations. No change has been
made to the final rule.
3.11 LEGAL CONSIDERATIONS
Comment: Two commenters (IV-D-24, IV-D-49) argued that
the EPA has no legal basis for establishing the MACT floor for
new plants based upon permit data, but rather should have
based the floor on actual emissions data. The commenters
argued that this improper use of permit limits resulted in
MACT floors that were not as stringent as they should be. One
of the commenters (IV-D-24) also argued that Congress intended
the phrase, "average emission limitation achieved" in
section 129(d)(3) to mean actual emission rates, and that
Congress could not have intended to refer to permitted
emission levels when actual emissions are lower than permitted
levels. The commenter noted that although section 302(k)
defines emission limitation, that section was adopted to
clarify that emission standards may include work practice
standards in response to a 1978 Supreme Court decision, and
the EPA has never interpreted the phrase to require it to use
permit data when actual emission data are available.
Moreover, the commenter argued that nothing in the 1990
Amendments indicates that Congress intended such a result.
The other commenter (IV-D-49) contended that only emissions
data that are based upon a facility utilizing a superior
control technology, using GCP's to maximize superior
performance, and materials separation represent the best
performing unit and the most stringent, maximum achievable
control specified by the Act.
Response: The EPA did not base MACT floors for new MWC
units upon permit data; thus, the commenters' arguments are
inapplicable to the NSPS. (They are, however, addressed in
the BID for the MWC emission guidelines that also are being
promulgated today because the MACT standards for existing
units were based upon regulatory and permit data.) As
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discussed in the proposal and promulgation preambles, the EPA
based the MACT standards for new units on the capabilities of
the technology that is used by the best controlled similar
source for each category.
Comment: Four commenters (IV-D-20, IV-D-68, IV-D-90,
IV-D-98) contended that the EPA lacks authority under the Act
to construct the MACT floor by choosing the best performing
unit separately for each pollutant. They argued that the
language of section 129 requires the EPA to consider a single
"best controlled unit" for all pollutants as the standard for
determining the new-source MACT floor. The commenters further
argued that the EPA's approach contravenes Congress' intent to
reflect both plant-specific constraints and the technical
limitations of pollution control technology. Two commenters
(IV-D-90, IV-D-98) also stated that if Congress had intended
for the EPA to use something other than the single best
performing unit when it determined the MACT floor, it would
have used different language.
Response: The EPA does not agree that the language of
the statute requires the MACT floors to be based upon one
overall unit. Rather, as set forth in greater detail below,
the EPA believes that the statute and case law support its
interpretation that it is legally permissible for the EPA to
set the MACT floor pollutant-by-pollutant, as long as the
various MACT floors do not result in standards that are not
achievable. In any case, as the data presented in section 3.5
indicate, 12 MWC units are now operating with the combined
technologies (SD/FF/SNCR and carbon injection) and all are in
compliance with the limits being promulgated.
Statutory Language
Section 129(a)(2) requires the EPA to establish
technology based emission standards that "reflect the maximum
degree of reduction in emission of air pollutants listed under
section (a)(4) that the Administrator, taking into
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consideration the cost of achieving such emission reduction
and any non-air quality health and environmental impacts and
energy requirements, determines is achievable . .
Congress further specified in section 129(a)(2) the minimum
reduction that could satisfy this requirement (i.e., the MACT
floor) for new sources as "the emission control that is
achieved in practice by the best controlled similar unit, as
determined by the Administrator." This language does not
expressly address whether the floor may be established
pollutant-by-pollutant. The "emission control achieved by the
best controlled similar unit" can be read either to mean
emission control as to a particular pollutant, or emission
control that is achieved by the unit as a whole.
Other statutory provisions are relevant, although they
also do not decisively address this issue. Section 129(a)(4)
requires MACT standards for, at minimum, PM, opacity, sulfur
dioxide, hydrogen chloride, oxides of nitrogen, carbon
monoxide, lead, cadmium, mercury, and dioxins and
dibenzofurans emitted by MWC's. This provision certainly
appears to direct maximum reduction of each specified
pollutant. Moreover, although the provisions do not state
whether there is to be a separate floor for each pollutant,
the fact that Congress singled out these hazardous air
pollutants ("HAP's") suggests that the floor level of control
need not be limited by the performance of devices that only
control some of these HAP's well.
Legislative History
One commenter (IV-D-98) cited the following exchange
between Senators Dole and Durenberger to support its argument
that Congress did not intend the EPA to establish the MACT
floor pollutant-by-pollutant:
Dole: It is entirely possible that different
technologies may reduce one pollutant
better than another. For example,
technology A may reduce heavy metals
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better than technology B while technology
B may reduce particulates better than
technology A; yet, one would not be
compatible with the other. I would assume
that the EPA would have adequate
discretion to balance environmental
benefits to determine which technology on
the whole represents a better MACT ....
Durenberger: The Senator is correct. Where differing
air pollution control technologies result
in one technology producing better control
of some pollutants and another producing
better control of different pollutants but
it is technically infeasible according to
the MACT definition to use both, the EPA
should judge MACT to be the technology
which best benefits human health and the
environment on the whole.
Leg. Hist, of 1990 Clean Air Act Amendments at 1129
(Oct. 26, 1990) (emphasis added) [hereinafter Leg. Hist.1.
Rather than supporting the commenter's argument that it is
improper for the EPA to determine the MACT floor pollutant-by
pollutant, the above exchange provides a strong indication
that Congress intended for the controls for each pollutant to
be optimized.
The quoted passage does not explain directly how the
floor is to be calculated for multiple HAP's; however, it doe
state that all HAP's are to be reduced to the maximum extent
possible and discusses how the EPA is to proceed i_f there are
two incompatible control technologies. Developing a separate
floor for each HAP obviously promotes the type of maximum per
pollutant reduction contemplated by the Report. See also
Chemical Manufacturers Ass'n v. EPA, 870 F.2d 177, 239 (5th
Cir. 1989) and 885 F.2d 253, 264 (5th Cir. 1989) (on
rehearing) construing the technology-based standards of the
Clean Water Act as allowing the EPA to "determine the 'best'
plant upon which to base [Best Available Technology]
limitations on a pollutant-by-pollutant basis." Since the ai
toxics provisions of the Clean Air Act are substantially
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modelled on those of the Clean Water Act (see, remarks of Sen.
Durenberger, 136 Cong. Rec. S516, Jan. 30, 1990), the fact
that a pollutant-by-pollutant approach is permissible under
the Clean Water Act further supports the EPA's interpretation
that it also is permissible under the CAA to set MACT
standards pollutant-by-pollutant, as long as the standards are
achievable. As discussed in section 3.5, the EPA has
collected data that demonstrate the achievability of the final
standards promulgated today.
In summary, Congress has not spoken to the precise
question at issue; however, the EPA's interpretation that a
MACT floor can be determined for each HAP surely achieves the
CAA's statutory goals and policies in a reasonable manner.
The central purpose of the amended air toxics provisions,
including section 129 and section 112, was to apply strict
technology-based emission controls on HAP's. See e.g., H.
Rep. no. 952, 101st Cong. 2d sess. 338. The floor's specific
purpose was to ensure that consideration of economic and
other impacts could not be used to "gut the standards." Lea.
Hist. at 2897 (statement of Rep. Collins). As Representative
Collins further noted, "[t]here needs to be a minimum degree
of control in relation to the control technologies [i.e., more
than one technology] that have already been attained by the
best existing sources." Id. (emphasis added). The EPA's
approach of developing floors pollutant-by-pollutant fulfills
this objective.
Conversely, an alternative interpretation would tend to
result in least common denominator floors where multiple HAP's
are emitted, whereby floors would no longer be reflecting
performance by the best performing sources. For example, if
the best performing 12 percent of facilities for HAP metals
did not control organics as well as a different 12 per cent of
facilities, the floor for organics and metals would not
reflect best performance. Having separate floors for metals
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and organics in this example certainly promotes the stated
purpose of the floor to provide a minimum level of control
reflecting what best performing sources have demonstrated
ability to do. Accordingly, for all of the above reasons, the
EPA based the final rule on MACT floors that were determined
pollutant-by-pollutant.
Consideration of Cost
One commenter (IV-D-49) stated that section 129(a)(2)
precludes the EPA from considering costs and other impacts
when setting the MACT floor. The EPA agrees with this
comment. Pursuant to section 129(a)(2), the EPA did not
consider costs when it determined the MACT floors.
Comment: Several commenters (IV-D-20, IV-D-85, IV-D-90,
IV-D-98) argued that the EPA's method for choosing the best
performing unit separately for each pollutant results in MACT
floors that are too stringent, and the available data indicate
that several of the standards, including some set at the MACT
floor, are not achievable continuously. The commenters
asserted that it is established beyond a doubt that to satisfy
the legal achievability criteria, the EPA must show that all
affected units will be able to meet continuously the
promulgated limits through proper use of the control
technology under foreseeable, worst-case operating conditions.
Response: The EPA agrees with the comments that
promulgated standards must be achievable, but disagrees with
the conclusions drawn by the commenters that the standards
promulgated today either cannot be achieved continuously, or
must be standards that are already being achieved in the
industry. (See section 3.4 for a response to the technical
issues raised by these comments.) First, as discussed in
section 3.4.1, the EPA obtained emissions data for 12 MWC
units for all pollutants that are regulated under the final
NSPS, and the data show that the final emission standards for
all pollutants are achievable by all 12 units. These 12 units
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are representative of MWC's that will be subject to the NSPS.
The EPA has placed data in the docket that establishes that
the MACT standards promulgated today are achievable.
Secondly, even in the absence of this data, the standards
would be permissible, because an achievable standard does not
have to be one that already is routinely achieved in industry;
the standard only must be "within the realm of the adequately
demonstrated system's efficiency . . Essex Chemical Corp.
v. Ruckelshaus, 480 F.2d 427, 433-34 (D.C.C. 1973). See also
Chemical Manufacturers Ass'n v. EPA, 885 F.2d 253, 264 (5th
Cir. 1989) (while upholding technology-based water standards
determined on a pollutant-by-pollutant basis, the court stated
that "the fact that no plant has been shown to be able to meet
all of the limitations does not demonstrate that all the
limitations are not achievable").
Comment: One commenter (IV-D-98) contended that the EPA
must apply section 129 according to its purposes and not those
of section 112. The commenter stated that regardless of
Congress' intent with respect to parallel provisions in
section 112, the EPA must interpret section 129 provisions
such that they reflect Congress' intent to regulate MWC's
separately from section 112 HAP's.
Response: As the responses to the individual legal
comments raised in this document indicate, the EPA based the
NSPS and the emission guidelines on the requirements of
sections 129 and 111 and the legislative history applicable to
these sections.
Comment: One commenter (IV-D-20) argued that in drafting
section 129(a)(4), Congress did not intend for the EPA to
establish a "no control" emission limitation if MACT for a
subcategory does not control for a particular pollutant. The
commenter thus disagreed with the EPA's conclusion that
section 129(a)(4) required it to promulgate a NOx emission
limitation at small MWC plants and existing large mass
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burn/refractory MWC's when the EPA had determined that MACT
for these units was "no control." The commenter further
stated that despite the EPA's statements in the proposed rule
that the proposed "no control" limitation of 500 ppm for these
units was neither intended to result in emission control, nor
to require any testing, reporting, or recordkeeping, some
States would feel obligated to impose such requirements in
order to determine the MWC's compliance status with respect to
this limitation.
Response: The EPA agrees with the interpretation given
by the commenter that Congress did not intend for
section 129(a)(4) to require an emission limitation where MACT
for a pollutant in a subcategory is "no control." To
eliminate any confusion on implementation of the standards,
the final rule does not include a numerical NOx emission
limitation for MWC's at small plants and existing large mass
burn/refractory MWC's. As stated in the preamble to the
proposed rule, the EPA did not expect that the "no control"
limit would be exceeded; thus, the final rule simply clarifies
that at this time, the EPA is not requiring NOx emission
controls on these units, nor any testing, reporting, or
recordkeeping with respect to NOx emissions from these units.
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4.0 MUNICIPAL WASTE COMBUSTOR NEW SOURCE PERFORMANCE
STANDARDS - SITING REQUIREMENTS
4.1 SITING ANALYSIS
4.1.1 Selection of Siting Analysis Requirements
Comment: Several commenters (IV-D-02, IV-D-18, IV-D-43,
IV-D-44, IV-D-75, IV-D-80, IV-D-84, IV-D-96, IV-D-98) objected
to the proposed siting requirements because they are
duplicative of impact analyses and siting analyses already
required in existing Federal, State, and local programs and
are, therefore, unnecessary. The commenters argued that the
EPA should rely on these existing analyses, rather than new
ones.
One commenter (IV-D-84) argued that the proposed siting
requirements are duplicative of NEPA requirements, with the
possible exception of the visibility issue. However,
visibility and visual impacts are aesthetic and local zoning
issues according to the commenter. The commenter stated that
the proposal will only give MWC opponents additional
opportunity to use "not-in-my-backyard" arguments against
proposed MWC's.
One commenter (IV-D-98) stated that the EPA, in
preparing the proposed siting requirements, has ignored the
fact that any new MWC facility will be required to conduct
full local and State land-use and zoning reviews before a
community can commit to a project. The commenter suggested
that the air quality and other environmental impact analyses
mandated by NSR and State NEPA-type requirements will already
provide the type of data contemplated by the proposal. The
commenter recommended that, at most, the siting analysis
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should include a provision that SIP's require a health risk
assessment as a component of pre-construction permit
applications for any proposed major source.
Five commenters (IV-D-18, IV-D-43, IV-D-44, IV-D-54,
IV-D-80) argued that the proposed requirements should be
removed because they are duplicative of and require nothing
more than the current NSR program. Two commenters (IV-D-54,
IV-D-80) added that the proposed siting requirements contain
none of the specificity of the NSR program, such that the
proposed program will be meaningless and impose unnecessary
costs.
Several commenters (IV-D-28, IV-D-43, IV-D-44, IV-D-67,
IV-D-98, IV-D-99, VI-B-02, VI-B-05, VI-B-06) stated that the
proposed siting requirements must be more explicit in what an
applicant would be required to perform. Three commenters
(IV-D-44, IV-D-67, IV-D-98) argued that the NSPS must contain
substantive requirements to guide the applicant and the EPA
when determining whether the siting analysis and response to
public comments are adequate. Four commenters (IV-D-28,
VI-B-02, VI-B-05, VI-B-06) stated that, without clear and
unequivocal guidance for the siting analysis, third parties
may legally challenge MWC applicants for failure to comply
with the intent of the rule.
One commenter (IV-D-98) added that the proposal contains
no criteria by which a particular site selection may be
endorsed or rejected and apparently requires no more than the
analyses needed for NSR. The commenter argued that without
clear criteria, the proposal could conflict with the Due
Process Clause of the Constitution [see, e.g., Parham v. J.R.,
442 U.S. 584 (1979)].
One commenter (IV-D-44) recommended that if the EPA does
not expect the applicant to do more under the NSPS than under
the NSR program, the proposed rule should say so explicitly.
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Response: The EPA is required by section 129(a)(3) of
the Act to adopt siting requirements for MWC's "that minimize,
on a site-specific basis, to the maximum extent practicable,
potential risks to public health or the environment." The
siting requirements under this rule were intentionally
structured to be similar to NSR in order to make use of
available information and general enough to avoid conflicts
between the programs. The siting analysis required under the
NSPS will allow plants to use the same information for
complying with both NSR and NSPS requirements as well as other
existing Federal, State, and local programs. This rule's
siting requirements will not cause added delay if they are
done concurrently with NSR impact analyses and other
requirements.
The siting requirements should not subject the MWC to
legal challenges on whether the intent of the rule has been
complied with. The NSPS siting requirements simply require a
procedure to be followed in siting an MWC as required under
section 129. As long as the procedure in the rule is followed
(i.e., the analysis is performed and public notice and comment
requirements are followed), the MWC has complied with the
section 129 requirements.
Comment: Five commenters (IV-D-28, IV-D-44, IV-D-67,
IV-D-98, IV-D-99) concluded that it would be unreasonable for
an applicant to provide background data for all nine
pollutants regulated by the proposed NSPS for other emission
sources in the area of the proposed MWC. The commenters
pointed out that many of these data would be unavailable and
that it would be expensive or impossible to obtain. The
commenters requested clarification on the requirements for an
air quality impact analysis.
Two commenters (IV-D-44, IV-D-99) recommended that if the
EPA requires a siting analysis, the NSPS should make it clear
that applicants need to use only the data that are publicly
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available from the EPA or the State agency. The commenters
argued that the applicant should not be required to collect
additional ambient air quality data, meteorological data, or
stack test data to conduct the siting analysis.
One commenter (IV-D-98) speculated that, even if
monitoring data on all pollutants regulated by the proposed
NSPS could be reasonably obtained for other sources in the
area, siting an MWC would be impossible because the EPA's own
Draft Reassessment of the Health Effects of Dioxins and Furans
states that "any more emissions of dioxin are unacceptable."
Response: The wording in the proposed siting
requirements in proposed § 60.576(b)(1) that specifically
required the owner or operator of a proposed MWC plant to
"[take] into account the impact of other major industrial
facilities near the affected facility" has been removed in the
final NSPS. Instead, the siting requirements specified in
section 129(a)(3) of the Act have been cited in the final NSPS
(under § 60.57b), as follows: "[the siting analyses shall]
minimize, ..., to the maximum extent practicable, potential
risks to public health or the environment." Interpretation of
this provision for the purpose of preparing a siting analysis
for a specific affected facility will be determined by the
regulating agency (usually the State).
Comment: Several commenters (IV-D-07, IV-D-42, IV-D-43,
IV-D-44, IV-D-67, IV-D-47, IV-D-60, IV-D-107, IV-D-115)
recommended that the proposed siting requirements include
specific siting restrictions. Two commenters (IV-D-43 and
IV-D-44) stated that although the proposed siting requirements
may quantify the potential impacts of a proposed MWC plant,
the siting requirements would not minimize the potential risks
unless they specifically restrict or prohibit the placement of
an MWC in certain areas, similar to the EPA's siting
requirements for landfills.
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Six commenters (IV-D-07, IV-D-42, IV-D-47, IV-D-60,
IV-D-107, IV-D-115) recommended that the siting requirements
include a set-back provision that would prohibit an MWC from
being built within a certain distance of residences, schools,
hospitals, or heavily populated areas. One commenter
(IV-D-47) supported the proposed siting analysis but
recommended that any new MWC be located no closer than
20 kilometers (12 miles) from any heavily populated area.
Response: There is insufficient basis for choosing a
single uniform set-back requirement to apply nationwide.
Exposure will depend on many factors such as MWC and control
design, topography, meteorology, and population activity
patterns in the area. The difficulty of setting a uniform
number is evidenced by the fact that different States
currently have different requirements for siting new plants.
A site-specific analysis with public input is the best way of
allowing consideration of local factors in local siting
decisions. The final rule includes no requirement for a
mandatory set-back. The final rule allows localities the
flexibility to determine on a site-specific basis whether a
set-back restriction is the best approach to minimize
potential risks to public health or the environment as
required under section 129. Refer to section 4.1.4 for
further discussion of the legal basis for the final siting
provisions.
4.1.2 Public Meeting Provisions for Siting Analysis
Comment: Several commenters (IV-D-28, IV-D-43, IV-D-44,
IV-D-67, IV-D-84, IV-D-85, IV-D-108, VI-B-02, VI-B-05)
objected to the proposed public meeting requirements because
they would be duplicative of the public review process already
provided for at the Federal, State and local level.
Three commenters (IV-D-28, VI-B-02, VI-B-05) stated that
the U.S. Treasury Department already requires public notice
and comments prior to the issuance of Industrial Development
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Bonds, a typical MWC financing mechanism. One commenter
(IV-D-84) also stated that public hearings are already
required under NEPA. Five commenters (IV-D-28, IV-D-44,
IV-D-67, IV-D-84, IV-D-85) noted that EPA's own PSD and NSR
programs already require public notices and the opportunity
for public hearings and comments.
Eight commenters (IV-D-28, IV-D-43, IV-D-44, IV-D-67,
IV-D-84, IV-D-108, VI-B-02, VI-B-05) stated that additional
requirements for public hearings are also unnecessary because
many State and local governments already require such hearings
as part of the air permitting process or as part of the zoning
and land use planning process. Therefore, these commenters
argued, the proposed requirements would be duplicative and
unnecessary and only increase costs without providing any
additional benefit or useful information.
One commenter (IV-D-84) added that public hearing
requirements should be left to the State and local elected
officials and not to Federal employees that are not located
near the project site. A second commenter (IV-D-85) stated
that local land use decisions are the province of local
government. Finally, one commenter (IV-D-108) opposed the
public hearing provisions because the commenter's State is
already conducting public hearings and the State has developed
solid waste advisory councils.
Response: Additional public meetings would not need to
be held in order to satisfy the siting requirements under this
rule. Because the siting analysis is based on the NSR
requirements, it is anticipated that if a public meeting is
scheduled to address the environmental impact analysis
required by the NSR program, the same public meeting could
also be used to discuss the siting analysis required by this
rule. The same meeting(s) could also be used to comply with
other requirements such as NEPA and State and local zoning
requirements.
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The public meeting provisions allow local authorities to
get involved. Most States, and some local agencies, are
delegated the authority to implement and enforce the NSPS.
4.1.3 Reporting and Recordkeeping Requirements for Siting
Analysis
Comment: One commenter (IV-D-111) recommended that the
siting requirements be clarified to indicate that NOx offset
commitments are not required as part of an initial application
to construct, but should "allow sources to secure the offset
at any time up until the source commences operation." This
would be consistent with the Nitrogen Oxide Supplement to the
General Preamble of the Act (Federal Register,
November 25, 1992). The commenter warned that offsets cannot
be identified early in the permitting process because permit
limits are often subject to revision and because offsets may
become unavailable from a potential source if the area
containing the source becomes or reverts to nonattainment
status for ozone.
Response: As indicated in an earlier comment response,
the NSPS siting requirements are based on the NSR
requirements. The NSPS siting requirements are intentionally
general in nature to prevent conflicts between this and other
program requirements and to allow other program requirements
that have already been established to provide guidance in
situations that the NSPS requirements do not address. The
issue of when NOx offsets are required to be identified and
committed to is not addressed in the NSPS but has already been
addressed in the Nitrogen Oxide Supplement mentioned by the
commenter. As the commenter correctly identified, the EPA*s
policy on NOx emission offsets is that emission reduction
credits that are federally enforceable and in effect by the
time the permitted source commences operation can be claimed
as offset credits. This policy will be codified in future
versions to the NSR regulations, which is the appropriate
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forum. The EPA* s policy on obtaining offset credits until
operation commences is already in place, eliminating
uncertainty regarding the number of offsets required to meet
emission limits and changes in attainment area status.
Therefore, the final rule has not been changed from that
proposed.
4.1.4 Legal Authority to Issue Siting Analysis Requirements
Comment: A number of commenters (IV-D-10, IV-D-28,
IV-D-43, IV-D-44) indicated that the EPA had failed in the
proposed rule to minimize potential risks from MWC's to public
health or the environment.
Response: The EPA's proposed siting requirements had two
components. The first component was based upon PSD
requirements, and required an analysis of the impact of the
affected facility on ambient air quality, visibility, soils,
and vegetation. The second component required the permitting
authority to take into account the impact of other major
industrial facilities near the affected facility. Several of
the commenters listed above stated that the proposed rule
failed to comply with the direction of Congress to develop for
new units "siting requirements that minimize, on a site
specific basis, to the maximum extent practicable, potential
risks to public health or the environment."
Section 129(a)(3). The commenters argued that the siting
requirements must include more than an NSR-type program in
order to protect public health and the environment, and that
the proposed rule only required risks to be quantified, but
did little or nothing to minimize potential risks as required
by the statute. As discussed in section 4.1.1, some
commenters (IV-D-28, IV-D-44, IV-D-67, IV-D-98, IV-D-99)
further argued that it will be difficult or impossible to
satisfy the second component of the proposed rule because the
applicant in many instances will not be able to determine the
emissions from other local facilities.
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The EPA agrees with these comments and has revised the
proposed rule. Under the final rule, owners and operators of
proposed new units must conduct an analysis of the impact of
the affected facility and select the site that minimizes, on a
site specific basis, to the maximum extent practicable,
potential risks to public health or the environment. The
final rule requires all new units to conduct a PSD type review
as part of its siting analysis. In addition, the final rule
gives local governments the discretion to determine, on a site
specific basis, and taking into account both the specific
facts that are peculiar to the location(s) being considered
and the public's input, whether the proposed location for the
new MWC minimizes potential risks to the public health and the
environment. Included in this analysis is the potential
impact to sensitive areas and/or individuals, such as schools,
health care facilities, children, and the elderly.
The final rule also requires owners and operators of new
MWC's to submit a materials separation plan as part of the
siting analysis. The materials separation plan is to be
tailored to the area that will be served by the MWC, thereby
providing for the consideration of the public and permitting
authority one method for removing pollutants before
combustion. The final rule, however, does not require that
materials separation be adopted; it only requires materials
separation to be considered as part of the siting analysis for
new MWC units.
Comment: Several commenters (IV-D-04, IV-D-99, VI-B-02,
VI-B-06) argued that the siting requirements for new MWC units
that are also being promulgated only should apply to entirely
new MWC's, and not modified or expanded units. Two commenters
(VI-B-02, VI-B-06) contended that the EPA only had authority
to issue siting requirements for new sources, but not for
existing sources. One commenter (IV-D-99) contended that the
siting requirements should not apply to the expansion of
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existing plants, where the expansion was considered in the
original siting analysis and approval. The commenter cited a
case where the siting, design, and permitting process for an
existing two-unit plant included provisions for adding a third
unit in the future. Another commenter (IV-D-51) recommended
that an existing unit that undergoes modifications that result
in a significant change in its potential emissions be required
to undergo a siting evaluation, including a risk assessment,
as part of the permit modification review process.
Response: As required by the express terms of the Act,
the final rule's siting requirements apply to both new units
and units that are modified, as that term is defined in
section 129(g)(3) of the Act. Section 129(a)(3) of the Act
expressly requires the EPA to develop siting requirements for
new units, and new units are defined in the Act to include
modified solid waste incinerator units:
The term "new solid waste incineration unit" means a
solid waste incineration unit the construction of
which is commenced after the Administrator proposes
requirements under this section establishing
emissions standards or other requirements which
would be applicable to such unit or a modified solid
waste incinerator unit.
42 U.S.C. § 7429(g)(2) (emphasis added). Modified solid waste
incinerator units are defined in section 129 as:
[A] solid waste incineration unit at which
modifications have occurred after the effective date
of a standard under subsection (a) of this section
if (A) the cumulative cost of the modifications,
over the life of the unit, exceed 50 per centum of
the original cost of construction and installation
of the unit (not including the cost of any land
purchased in connection with such construction or
installation) updated to current costs, or (B) the
modification is a physical change in or change in
the method of operation of the unit which increases
the amount of any air pollutant emitted by the unit
for which standards have been established under this
section or section 7411 of this title.
42 U.S.C. § 7609(g)(3).
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Accordingly, the express terms of the statute require
owners and operators to perform siting analyses for any
existing MWC that is modified within the meaning of
section 129(g)(3). Under the final rule, such analyses
require the owner or operator to propose the location that
minimizes, on a site specific basis, to the maximum extent
practicable, potential risks to public health or the
environment. Although it may not be feasible to relocate an
existing MWC, such an analysis nonetheless remains appropriate
when evaluating whether an existing MWC should be modified
and/or expanded. A review of the siting analyses may
establish that expanding an existing unit (as opposed, for
example, to building a new unit in a different location) will
not minimize the potential risks to human health and the
environment. Excluding existing units undergoing
modifications within the meaning of section 129(g)(3) from the
siting requirements is both contrary to the Act and would
defeat the goal of minimizing risks.
One commenter questioned whether existing units that are
modified in order to comply with the emissions guidelines
promulgated today under a separate final rulemaking notice
would be required to comply with the NSPS should the cost of
the modifications exceed the 50-percent threshold of
section 129(g)(3). Changes made to an existing MWC solely to
comply with an emission guideline are not considered a
modification or reconstruction and would not subject an
existing MWC to comply with the NSPS. In addition, the final
rules promulgated today require units to employ good
combustion practices, which constitute a relatively low
percentage of the overall cost of the unit. Thus, adoption of
GCP's will not trigger the 50 percent threshold.
Comment: Several commenters (IV-D-10, IV-D-28, IV-D-43,
IV-D-44) argued that in order to fulfill Congress' intent that
the siting requirements minimize potential risks to the public
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health and environment, the requirements specifically must
restrict or prohibit the placement of an MWC in certain areas,
similar to the EPA's siting requirements for landfills. One
commenter (IV-D-10) cited the September 24, 1992 Congressional
Record and a letter from Max Baucus, a member of the Senate
Committee on Environment and Public Works, to support this
contention.
Response: The EPA does not believe that the potential
risks to public health and the environment can only be
minimized through specific physical set-back requirements, but
it does agree that factors such as location (including
proximity to schools and health care facilities) and the
potential impact of emissions from a proposed MWC site on
sensitive individuals must be taken into account when
performing the siting analyses required by the final rule.
The final rule allows localities the flexibility to determine
which location minimizes the potential risk to human health
and the environment, based upon the various factors that are
unique to each site, without prescribing universal physical
setback standards. It also places the burden on owners and
operators of new MWC's (as that term is defined in
section 129(g)(2)) to justify their ultimate site choices in a
public forum, thereby allowing the permitting authority to
consider the public's input when it determines "on a site
specific basis" whether the proposed site minimizes the
potential risk to human health and the environment.
Comment: One commenter (IV-D-10) contended that limiting
the siting requirements to units that file initial
construction permit applications after the date of
promulgation is inconsistent with section 129(g)(2) of the
Act, which defines a new municipal waste combustor unit as one
that either commences construction after the rule is proposed
or is a modified MWC. The commenter noted that under the
proposed rules, an owner or operator can avoid the siting
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requirements merely be filing a construction permit
application before the NSPS are promulgated.
Response: The EPA agrees with these comments. The
proposed applicability date for the siting provisions is not
consistent with the section 129 requirements. In the final
rule, the EPA has included siting requirements for MWC's for
which construction is commenced after September 20, 1994;
however, the siting requirements are different for those
facilities for which construction is commenced between
proposal and promulgation. The final rule includes the
following requirements for the following two groups of
affected facilities: (1) Affected facilities for which the
initial application for a construction permit under 40 CFR
part 51, subpart I, or part 52, is submitted after the date of
promulgation, must prepare a siting analysis and materials
separation plan in accordance with the provisions specified in
the final rule (the siting provisions have been revised since
proposal; refer to other discussions in this section for a
summary of the changes); and (2) affected facilities for which
construction is commenced after September 20, 1994 and that
are not subject to requirement (1) above are required to
prepare a siting analysis in accordance with 40 CFR part 51,
subpart I, or part 52, as applicable.
4.1.5 Applicability of the Siting Requirements
Comment: Several commenters (IV-D-04, IV-D-99, VI-B-02,
VI-B-06) argued that the siting requirements for new MWC units
that are also promulgated today under separate notice only
should apply to entirely new MWC's, and not modified or
expanded units. Two commenters (VI-B-02, VI-B-06) contended
that the EPA only had authority to issue siting requirements
for new sources, but not for existing sources. One commenter
(IV-D-99) contended that the siting requirements should not
apply to the expansion of existing plants, where the expansion
was considered in the original siting analysis and approval.
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The commenter cited a case where the siting, design, and
permitting process for an existing two-unit plant included
provisions for adding a third unit in the future. Another
commenter (IV-D-51) recommended that an existing unit that
undergoes modifications that result in a significant change in
its potential emissions be required to undergo a siting
evaluation, including a risk assessment, as part of the permit
modification review process.
Response: As required by the express terms of the Act,
the final rule's siting requirements apply to both new units
and units that are modified, as that term is defined in
section 129(g)(3) of the Act. Section 129(a)(3) of the Act
expressly requires the EPA to develop siting requirements for
new units, and new units are defined in the Act to include
modified solid waste incinerator units:
The term "new solid waste incineration unit" means a
solid waste incineration unit the construction of
which is commenced after the Administrator proposes
requirements under this section establishing
emissions standards or other requirements which
would be applicable to such unit or a modified solid
waste incinerator unit.
42 U.S.C. § 7429(g)(2) (emphasis added). Modified solid waste
incinerator units are defined in section 129 as:
[A] solid waste incineration unit at which
modifications have occurred after the effective date
of a standard under subsection (a) of this section
if (A) the cumulative cost of the modifications,
over the life of the unit, exceed 50 per centum of
the original cost of construction and installation
of the unit (not including the cost of any land
purchased in connection with such construction or
installation) updated to current costs, or (B) the
modification is a physical change in or change in
the method of operation of the unit which increases
the amount of any air pollutant emitted by the unit
for which standards have been established under this
section or section 7411 of this title.
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42 U.S.C. § 7609(g)(3).
Accordingly, the express terms of the statute require
owners and operators to perform siting analyses for any
existing MWC that is modified within the meaning of
section 129(g)(3). Under the final rule, such analyses
require the owner or operator to propose the location that
minimizes, on a site specific basis, to the maximum extent
practicable, potential risks to public health or the
environment. Although it may not be feasible to relocate an
existing MWC, such an analysis nonetheless remains appropriate
when evaluating whether an existing MWC should be modified
and/or expanded. A review of the siting analyses may
establish that expanding an existing unit (as opposed, for
example, to building a new unit in a different location) will
not minimize the potential risks to human health and the
environment. Excluding existing units undergoing
modifications within the meaning of section 129(g)(3) from the
siting requirements is both contrary to the Act and would
defeat the goal of minimizing risks.
One commenter questioned whether existing units that are
modified in order to comply with the emissions guidelines
promulgated today under a separate final rulemaking notice
would be required to comply with the NSPS should the cost of
the modifications exceed the 50-percent threshold of
section 129(g)(3). Changes made to an existing MWC solely to
comply with an emission guideline are not considered a
modification or reconstruction and would not subject an
existing MWC to comply with the NSPS. In addition, the final
rules promulgated today require units to employ good
combustion practices, which constitute a relatively low
percentage of the overall cost of the unit. Thus, adoption of
GCP's will not trigger the 50 percent threshold.
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4.1.6 Miscellaneous
Comment: One commenter (IV-D-45) argued that it is the
responsibility of the EPA or the industry, rather than the
community that is at risk, to prove that the MWC is safe.
According to the commenter, the EPA has allowed the siting of
MWC's without adequate study by the EPA or the industry to
prove that they are not harmful to public health. The
commenter pointed out that, in contrast, the Food and Drug
Administration requires that new drugs be proven safe and
effective before they are marketed and the Federal Aviation
Administration requires that new aircraft be structurally safe
before they are marketed or used by airlines.
Response: The proposed NSPS and emission guidelines
limit MWC emissions to the maximum extent possible in order to
minimize risks to the public and the environment. The
proposed siting requirements also minimize risks by
identifying those sites, on a case-by-case basis, that may
present unreasonable risks. However, as with new drugs and
with aircraft, it is impossible to eliminate all risk without
also eliminating the benefits of the technology. The proposed
NSPS is a compromise that reduces risks in consideration of
local inputs.
Comment: One commenter (IV-D-108) stated that it is
inappropriate for the EPA to be involved in local siting
decisions because of EPA's lack of involvement in MSW
management and planning and facility siting, and EPA's lack of
knowledge of local siting concerns. The commenter argued that
siting decisions must remain at the local level. Adding a
redundant level of Federal regulation and oversight would
waste State and local resources, require an unprecedented
level of EPA involvement in local decisions, and slow the
entire process, according to the commenter.
Response: The NSPS siting requirements are structured so
that the process and all decisions will occur at the State and
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local level. The proposed siting requirements establish a
procedure to ensure a minimum level of review with local
public input for all new MWC's. Where current siting
practices are consistent with the proposed NSPS, those
practices will be accepted as compliance with the NSPS.
Almost all States and several local agencies have been
delegated the authority to implement NSPS. Therefore, no
change is required to the proposed language. The agency
delegated implementing authority, rather than EPA, will make
siting decisions.
4.2 MATERIALS SEPARATION PLAN
4.2.1 Selection of Materials Separation Plan Requirements
Comment: One commenter (IV-D-57) noted that if materials
separation is inappropriate for some subareas, it is possible
it may be inappropriate for an entire service area and a
mandatory plan may, therefore, be unnecessary. Requiring a
plan at every site would be inconsistent with EPA's goal of
adapting waste management to the needs of each community,
according to the commenter.
Response: There may be some cases where materials
separation may be inappropriate for an entire service area of
an MWC. However, as stated in the EPA report "The Solid Waste
Dilemma: An Agenda for Action" (EPA/530-SW-88-052),
integrated strategies are needed for waste disposal and, on a
national basis, the preferred hierarchy of waste management is
(1) source reduction, (2) recycling of materials, and
(3) incineration and landfilling. In order to make the
determination that materials separation is not appropriate for
a service area and that a materials separation plan is,
therefore, unnecessary, the applicant must follow the analysis
and public comment procedures in the NSPS and consider the
feasibility and benefits of recycling and materials
separation.
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The applicant must prepare a draft materials separation
plan and hold a public meeting to accept comments on the draft
plan. The applicant must then develop a document that
summarizes and responds to the public comments on the draft
plan. The applicant must then prepare a final materials
separation plan. Based on the initial analysis and public
comments, the draft and final materials separation plans may
conclude that materials separation is not appropriate in the
service area of the proposed MWC. However, the applicant must
still accept public comment on the initial determination,
respond to the comments, and provide a rationale for the final
determination. The final NSPS has been revised to account for
those situations in which a materials separation plan is not
appropriate for an entire service area.
Comment: Four commenters (IV-D-43, IV-D-44, IV-D-51,
IV-D-56) stated that the proposed materials separation plan
should only be required as a condition to obtain a permit, but
should not become a condition of an air permit.
One commenter (IV-D-51) agreed that recycling and waste
reduction should be encouraged and considered when sizing a
new MWC and recommended that a materials separation analysis
be required and made available for public review. However,
the commenter recommended that the inclusion of a plan in the
actual permit be optional because the public review may
indicate that no plan is needed for a specific MWC.
Response: The materials separation plan provisions are a
one-time procedural requirement and do not contain any
enforcement provisions. The materials separation plan
provisions are intended to ensure that new MWC's are sized
appropriately for the amount of MSW generated in a service
area after all appropriate source reduction and recycling
measures of public interest have been implemented. The
materials separation plan provisions only require the owner or
operator of a proposed MWC to consider the effect of current
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and projected material separation and recycling programs in
the service area of the MWC on the quantity and character of
MSW that will be brought to the MWC. The NSPS also requires
the owner or operator to solicit and consider public input on
the effect of these recycling and separation programs on the
projected size of the MWC. The NSPS does not require the
owner or operator to implement the activities specified in the
plan after the plan has been finalized.
Comment: Several commenters (IV-D-18, IV-D-73, IV-D-74,
IV-D-103, IV-D-120, VI-B-02, VI-B-05) recommended that the
NSPS should be more specific as to the requirements of the
material separation plan. One commenter (IV-D-18) stated that
the proposed NSPS provide no standard for ratifying or
evaluating the impacts of a proposed plan and, therefore,
leave the opportunity open for legal challenges to any project
on the basis of the materials separation plan. One commenter
(IV-D-103) questioned whether the proposal was intentionally
left vague to allow for flexibility in plan requirements. Two
commenters (VI-B-02, VI-B-05) urged the EPA to provide clear
procedural requirements to guide the applicant and the EPA in
determining when a materials separation plan and the
applicant's responses to public comments were adequate.
One commenter (IV-D-73) noted that without specific
guidance from the EPA, the requirements of the plan would be
largely determined by input from the people who attend the
public hearings.
One commenter (IV-D-120) did not support the materials
separation plan requirement because it did not specify
measures that would minimize air emissions or the impacts of
controlling air emissions (e.g., measures affecting ash
quality). The commenter stated that the proposed requirement
appeared to be an effort to encourage recycling, but such an
effort would be misplaced in this rule because only about
16 percent of MSW is incinerated.
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Response: An applicant for a new MWC would not be left
open to legal challenges on the basis of the materials
separation plan as long as the applicant fulfilled the
procedural requirements in the NSPS for public review and
comment on the materials separation plan. The public review
and comment process is intended to result in a materials
separation plan that reflects local public input, including
input from those attending public meetings, and is tailored to
the particular needs of the service area of the MWC. For
these reasons, the materials separation plan requirements do
not specify performance levels, separation system elements, or
the materials to be separated.
The materials separation plan provisions require the MWC
applicant to consider current and projected MSW generation
rates and the impact of source reduction and recycling on the
quantity and character of the MSW that serves as the MWC
feedstock. These are important factors in determining the
size of the MWC and, therefore, are appropriate siting
considerations within the scope of this rulemaking. The
materials separation plan provisions are not intended to
directly address or reduce MWC air emissions of specific
pollutants. However, the materials separation plan
requirements may indirectly encourage recycling in some cases.
Comment: One commenter (IV-D-74) supported the materials
separation plan requirement and recommended that the EPA
specify that certain items be separated or eliminated from the
MSW stream, including fluorescent light tubes, sources of
dioxins/furans (PCB's, plastics, and chlorinated aromatic
hydrocarbons), and appliances containing Hg. According to the
commenter, emissions are directly related to the incineration
of products in the waste stream, particularly those that
contribute to emissions of heavy metals and dioxins/furans.
One commenter (IV-D-24) recommended that the final rule
require plans for both new and existing MWC's to phase-out
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incineration of the following: batteries (including, but not
limited to, Hg, silver-oxide, and nickel-cadmium batteries),
fluorescent light tubes, Hg thermometers, switches and
thermostats, metal-containing inks, plastics with metal
pigments or stabilizers, chrome-tanned leather clothing,
leaded glass, gypsum, PVC bottles, PVC or "PVDC" wrap, and
bleached paper. The commenter also recommended a 25-percent
reduction in the incineration of the following materials:
bi-metal cans, aluminum cans, yard waste, and food waste. The
commenter (IV-D-24) recommended that the plan require
separation of any material that can be shown to result in
achievable emission reductions, defined to include, but not
limited to, any source reduction that is cost-effective or
provides a net profit to the operator or to the municipality
contracting for MSW services. The plans should spell out in
detail how these wastes would be separated, recycled, or
otherwise treated.
The commenter (IV-D-24) referred to several studies to
support the commenter's recommended materials separation
requirements to reduce HC1 and dioxin/furan emissions by
preventing sources of chlorine from entering the MWC. The
commenter noted that in Japan in the 1970's, half of the
municipalities chose a plastic separation program to comply
with a nationwide HC1 emission limit of 430 ppm (International
Cooperation Agency, Japan, Solid Waste Management and Night
Soil Treatment, Volume I).
One commenter (IV-D-17) recommended that the EPA require
collection and separation programs to prevent Hg-containing
materials from entering the waste stream and to remove Hg and
other metal-containing materials. The commenter stated that
these pollution prevention strategies represent a more
effective environmental strategy than focusing on add-on
controls. However, the commenter stated that the EPA should
not abandon support for advanced control measures.
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Response: The proposed materials separation plan
requirements do not specify the materials to be separated.
The materials separation plan requirements are intended to
ensure that MWC's are properly sized to account for current
and future MSW generation rates and the impact of current and
future source reduction and recycling on the character and
quantity of MSW that will be the MWC feedstock. However, the
materials separation plan requirements do not preclude a local
authority from separating any specific materials. In
addition, MWC owners and operators are free to use any control
technology they choose to comply with the numerical emission
limits (including separating specific materials), as long as
they demonstrate compliance.
The commenters provided no data to indicate that the
commenter's recommended separation requirements for specific
materials and items would be economically feasible or would
reduce emissions below the numerical emission limits
established in this rulemaking. Additionally, the commenter
provided no data on the actual HC1 emission reduction that
were achieved through the Japanese plastic separation program.
The Japanese HC1 emission limit of 430 ppm is many times
higher than the NSPS emission limit of 25 ppm.
Comment: One commenter (IV-D-24) noted that tests at an
MWI indicate that a high chlorine content in the feed from PVC
plastics and bleached paper can overcome GCP (indicated by a
50 ppm CO concentration) and result in dioxin/furan emissions
of over 1,000 ng/dscm (Jenkins, A.C., et al., "Evaluation Test
on a Hospital Refuse Incinerator at Saint Agnes Medical
Center, Fresno, California," California Air Resources Board,
January 1987). Based on these results, the commenter stated
that one potential method to reduce dioxin/furan emissions is
for the EPA to ban PVC items from MWC's and to require a
phase-out of the bleaching of paper products.
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Response: Medical waste incinerators are being regulated
by a separate set of emission standards under the Act because
of differences in feedstock, combustor type, and control
technology. The NSPS emission limit for dioxins/furans of
13 ng/dscm is far less than the 1,000 ng/dscm cited by the
commenter. The emission guideline limit for existing units at
large plants is 30 ng/dscm for units with non-ESP based APCD's
and 60 ng/dscm for units with ESP-based APCD's, and the limit
for existing units at small plants is 125 ng/dscm. These are
also far less than 1,000 ng/dscm.
Comment: One commenter (IV-D-24) cited a study at an
incinerator that measured the dioxin/furan emissions at three
different chlorine concentrations ("Results of the Combustion
and Emissions Research Project at the Vicon Incinerator
Facility in Pittsfield, Massachusetts -- Final Report,"
#87-16, prepared for New York State Energy Research and
Development Authority by Midwest Research Institute, June,
1987). Although the commenter states that the study's authors
concluded that the test results were not statistically
significant, the commenter says that the study supports the
need to reduce PVC in waste and the proposition that
dioxin/furan emissions are directly proportional to chlorine
content.
Response: The authors of the study cited by the
commenter concluded that the results are not statistically
significant and do not show any relation among the three
chlorine feed rates and dioxin/furan emissions. Therefore,
these results do not support the commenters argument that
dioxin/furan emissions are directly proportional to chlorine
content and that PVC in MSW must be reduced.
Comment: One commenter (IV-D-24) argued for the removal
of paper and plastic from MSW since European studies have
shown that these items may account for about 13 percent and
10 percent, respectively, of the Hg found in MSW ("Energy from
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Waste," Summary of a study by the National Energy
Administration and the National Swedish Environment Protection
Board, Stockholm, 1987). The commenter also cited two studies
indicating that metals in the flue gas may catalyze the
secondary formation of dioxins/furans (Stieglitz, L. "New
Aspects of PCDD/PCDF Formation in Incineration,"
International Workshop on Municipal Waste Incineration,
National Incinerator Testing and Evaluation Program,
Environment Canada, Montreal, Canada, October 1-2, 1987;
Environment Canada, "The National Incinerator Testing and
Evaluation Program: Environmental Characterization of Mass
Burning Incinerator Technology at Quebec City," Report
EPS 3/UP/5, June, 1988).
Response: The preferred MSW management hierarchy is:
(1) Source reduction, (2) recycling of materials, followed by
(3) incineration and landfilling. According to this
hierarchy, recyclable paper and plastic should be removed from
MSW. However, not all paper and plastic can be recycled, so
these materials must be either combusted for energy recovery
or landfilled. Also, it is not known whether the Hg content
of paper in Europe is comparable to that in the U.S. because
of differences in paper making processes and printing inks.
The use of Hg in printing inks was discontinued in the U.S. in
1991; therefore, any Hg found in paper is most likely due to
background levels in the raw materials.
Mercury is contained in many materials other than paper
and plastics, so removing the latter from MSW would not
necessarily decrease Hg concentrations in the MSW or in the
uncontrolled emissions. The commenter provided no data
demonstrating that removing all paper and plastic would reduce
Hg emissions below the Hg emission limits in the NSPS. In any
case, the final regulation will achieve greater than
85 percent control.
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Comment: One commenter (IV-D-24) stated that the State
of New Jersey Department of Environmental Protection has
concluded that its Battery Reduction Law and Toxics in
Packaging Law "will have a considerable effect on emissions"
by reducing Hg and other heavy metals in MSW. The New Jersey
Department of Environmental Protection estimated that fuel
cleaning would reduce Hg emissions by 70 to 95 percent,
according to the commenter. Finally, the commenter stated
that studies have shown that removing gypsum board and yard
waste from MSW would reduce emissions of SO2 and NOx,
respectively. The commenter concluded by stating that there
is no evidence suggesting that ambitious source reduction
would have a trivial impact on emissions and that the EPA
would have to provide evidence to conclude that the impact of
source reduction would be trivial.
Response: No data were provided to demonstrate that
New Jersey's Battery Reduction Law and Toxics in Packaging Law
have reduced Hg emissions below the numerical emission limits
in the NSPS or that the Hg reductions estimated by the
New Jersey DEP have been achieved. No data are available to
the EPA that would indicate that source reduction could reduce
SO2 and NOx emissions to levels below the numerical emission
limits in the NSPS or could achieve greater emission
reductions than the NSPS requirements. However, nothing in
the NSPS precludes an owner or operator from using source
reduction as a control technique to comply with the numerical
emission limits.
Comment: Several commenters (IV-D-18, IV-D-43, IV-D-44,
IV-D-54, IV-D-56, IV-D-57, IV-D-80, IV-D-85, IV-D-98,
IV-D-104) argued that there is no technical basis for
materials separation requirements in an air quality regulation
and that the EPA has failed to demonstrate that materials
separation would yield any air quality or nonair quality
benefits or reduce the risk to the public. One commenter
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(IV-D-44) pointed out that the EPA has consistently concluded
that a materials separation program should not be included in
the NSPS for MWC's. The commenter noted that the preamble for
the 1991 NSPS (subpart Ea) expressly rejected a proposal for a
materials separation program (56 FR 5496 - 5499) and that
there has been no change in the scientific or technical data
to justify a reversal of EPA's policy.
One commenter (IV-D-57) stated that the EPA has not
adequately justified the need for a materials separation plan
because the preamble does not show that materials separation
will be practicable or needed to minimize potential risks to
public health or the environment.
One commenter (IV-D-80) recommended that the materials
separation requirements be deleted because no correlation
between materials separation and emissions has been
established to date. If such a correlation exists, the
commenter agreed that materials separation could be pursued as
an alternative to other emission control options.
Five commenters (IV-D-43, IV-D-44, IV-D-67, IV-D-85,
IV-D-104) noted that previous BACT and PSD determinations by
the EPA have consistently concluded that materials separation
programs do not improve MWC emissions. One commenter
(IV-D-85) stated that PSD remand studies for the Brooklyn Navy
Yard Resource Recovery Project have shown that there is no N0X
reduction when yard waste is removed. The same commenter also
noted that the WASTE Project at the Burnaby/Vancouver, British
Columbia (Canada) MWC show that there are no emissions or ash
leaching benefits from the removal of certain heavy metals
from MSW.
One commenter (IV-D-104) cited two 1994 papers by Rigo,
Ferraro, and Wilson that concluded that fuel-bound nitrogen is
emitted more as N2 than as N0X in MB/WW MWC's and, therefore,
there are no changes in N0X emissions that are statistically
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related to the quantity of yard waste, wood, food, textiles,
or rubber in the MSW.
The same commenter (IV-D-104) also noted that published
data from the WASTE Project demonstrate that HC1 and metal
emissions are not related to the concentration of chlorides or
metals in the waste. The commenter stated that the WASTE
Project demonstrated that adding over seven times the normal
amount of Pb to an MWC in the form of lead-acid batteries
resulted in no increase in Pb emissions (Chandler, Rigo, and
Sawell, 1994; Rigo, Chandler, and Sawell, 1993). The
commenter noted that the two papers that he attached to his
comment letter conclude that recycling of lead-acid batteries
should be encouraged, but banning lead-acid batteries or
spending large sums of public money to police diversions
appears to be unwarranted because the environmental
significance of introducing limited numbers of batteries into
MWC's is limited.
The same commenter (IV-D-104) also noted that the WASTE
Project's Cd spiking experiments measured only a marginally
statistically significant increase in Cd emissions when Cd was
added in the form found in MSW. The authors of the WASTE
Project report concluded that commercially available PVC and
plastics using Cd colorants are probably not the source of Cd
emissions or occasionally high Cd leachate concentrations in
MWC ash (Chandler, Rigo, and Sawell, 1994) .
The same commenter (IV-D-104) also noted that the HC1 CEM
data from the WASTE Project indicate that HC1 emissions
downstream of a SD/FF are not correlated with the amount of
PVC waste entering the MWC. According to the commenter, this
result contradicts EPA's assertion in section 8.0 of the
"Economic Impact Analysis for Proposed Emission Standards and
Guidelines for Municipal Waste Combustors" (EPA-450/3-91-029)
that separating chlorine-containing materials from the waste
stream would reduce HC1 emissions.
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Finally, the same commenter (IV-D-104) noted that through
the waste characterization study at the Burnaby MWC, Rigo and
Chandler (1994) concluded that many environmentally
significant metals are constituents of natural waste
components and are not necessarily introduced during
manufacturing processes. The paper by Rigo and Chandler
concluded that there is a disparity between the popular
perception of the source of some metals in MSW and their
actual location. For example, batteries accounted for only
4 percent of the Hg in the Burnaby MSW; the majority is found
in low concentrations in the combustible fraction of MSW,
including paper, wood, and yardwaste. According to Rigo and
Chandler, the presumption that simply separating a metal will
reduce concentration in stack emissions and other residue
streams must be questioned because of a lack of correlations
between waste components and metal concentrations.
Response: The intended purpose of the materials
separation plan provisions is to be a planning process with
public input. It applies only to new MWC's. As part of the
siting requirements, the materials separation plan is intended
to ensure proper sizing of new MWC's to account for the impact
of current and projected MSW source reduction and recycling
programs within the context of ISWM. Ensuring the proper
sizing of MWC's and thorough consideration of MSW source
reduction, considering public input, will result in the use of
municipal waste incineration only to the extent that
incinerating is necessary, thereby minimizing air quality
impacts from MWC's. Therefore, the materials separation plan
provisions are consistent with previous EPA determinations and
other available data concerning the effect of materials
separation on MWC emissions.
4.2.2 Impacts of Materials Separation Plan Requirements
Comment: Two commenters (IV-D-28, IV-D-84) stated that
the proposed materials separation plan will put MWC's at a
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disadvantage and encourage landfilling. One commenter
(IV-D-84) stated that the plan will encourage hauling of MSW
across State lines to regional landfills. The commenter noted
that a curbside separation plan would add $100 to $200 per ton
to the cost of MSW disposal and a mixed waste processing plant
would add $40 to $80 per ton to the cost of MSW disposal. The
commenter also noted that the impacts of these costs would be
compounded by the absence of a policy that would allow States
to control waste flow within their boundaries.
Response: The materials separation plan provisions in
the NSPS are not prescriptive and do not require any specific
recycling or materials separation activities, only a public
discussion of these activities relative to the projected size
of the planned MWC. Therefore, the cost impacts of these
procedural requirements are expected to be minimal and will
have little, if any, effect on the cost of MSW disposal or on
a community's decision to select MSW combustion versus
landfilling. For similar reasons, the materials separation
plan provisions will not affect whether MSW is taken across
State lines to regional landfills.
The costs of recycling and materials separation will be
highly variable from one community to another and will be
affected by recent and future decisions on the issue of flow
control. However, the procedural requirements of the NSPS
will identify those activities that are appropriate for a
specific MWC and will, therefore, account for the economic
effect of decisions on the issue of flow control.
Comment: One commenter (IV-D-99) warned that
increasingly strict environmental requirements on local
governments, such as the proposed materials separation plan,
carry a cost that threatens the viability of recycling and
composting programs because budget cuts to balance these
environmental costs increasingly come from recycling and mulch
programs.
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Two commenters (IV-D-75, IV-D-96) added that the proposed
materials separation requirements represent a costly and
unnecessary duplication of the requirements already in place
in many municipalities.
Response: As discussed in the previous response, the
cost impacts of the procedural materials separation plan
requirements are expected to be minimal and will have little,
if any, effect on the cost of MSW disposal. The cost of
developing a materials separation plan is not a significant
component of the total cost of the NSPS. The cost impact of
the complete NSPS and the effects on local budgets are
discussed more fully in section 3.6.2 of this document.
The materials separation plan provisions are not a
duplication of the current recycling and material separation
efforts because current efforts can become the basis of the
materials separation plan. The only added burdens would be
the public meetings and documentation associated with
incorporating the existing program into the materials
separation plan. In many cases, the required meetings on the
separation plan could be combined with other meetings already
being held for PSD/NSR, zoning, or other State or local
requirements, and would not be an additional cost burden.
Therefore, the additional costs of the materials separation
plan should be minimal and should not affect the viability of
existing recycling and composting programs.
4.2.3 Compliance Provisions for Materials Separation Plan
Requirements
Comment: Four commenters (IV-D-02, IV-D-18, IV-D-31,
IV-D-99) recommended that owners and operators of MWC plants
in areas that already have plans meeting the goals of the
separation plan should not be subject to the requirement to
develop a materials separation plan.
Three commenters (IV-D-31, IV-D-85, IV-D-108) recommended
that the NSPS should contain a provision that would allow
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applicants to meet the materials separation plan requirements
by conforming with existing local, regional, or State MSW
reduction or management plans that are already achieving the
desired results, although not necessarily involving all of the
proposed procedures. One of the commenters (IV-D-108)
described the materials separation legislation and programs in
place in the commenter's State, which include State-wide
mandatory recycling of glass containers, aluminum cans,
newspaper and leaves. The commenter pointed out that, in
addition, nearly every county in the State also requires the
recycling of vehicle batteries, used motor oil, corrugated
cardboard, mixed paper, grass and brush, white goods, and wood
wastes.
One commenter (IV-D-31) recommended that the NSPS should
allow an applicant to waive the materials separation plan
requirements if the applicant can demonstrate that current
recycling programs in the service area have saturated the
markets for recyclable materials to the point where further
materials would negatively impact other recycling programs.
The owner or operator would be required to monitor markets and
develop a materials separation plan when market conditions
were favorable.
Response: The materials separation plan provisions in
the NSPS are procedural and are not prescriptive. The
provisions do not require the owner or operator to undertake
any specific material separation or recycling activities;
merely to consider the effect of current or future programs on
the quantity and character of MSW in selecting the size of the
MWC. The materials separation plan developed according to the
procedures in the NSPS could use existing programs as a
starting point. Furthermore, the information collected in the
public meeting and comment process required by the NSPS may
indicate that current activities are adequate and no
additional activities are required in the service area of the
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MWC. However, the procedural requirements of the NSPS must
still be followed to determine whether additional actions are
warranted or feasible in light of the proposed MWC.
If current recycling programs in an area have saturated
the markets for recyclable materials, then that fact will be
reflected in the materials separation plan developed during
the procedures required by the NSPS. In such a case, the
materials separation plan may require no additional separation
and recycling beyond that already performed. Nothing in the
NSPS would preclude an owner or operator from including a
provision in the materials separation plan to add or remove
certain materials separation or recycling activities at a
later time in response to market changes that make recycling
more or less favorable.
4.2.4 Public Meeting Provisions for Materials Separation Plan
Requirements
Comment: One commenter (IV-D-31) stated that public
input is appropriate but should not be used to stall project
development. The commenter recommended that the presentation
of the materials separation plan and the siting analysis
should be consolidated into one public meeting.
Response: The NSPS requires that the materials
separation plan be developed prior to conducting the siting
impact analysis because the size of the MWC will be affected
by the outcome of the materials separation plan development
process. Once the size of the proposed MWC is determined, the
siting impacts can be more accurately assessed. As a result,
the NSPS requires separate meetings to present the materials
separation plan and the results of the siting analysis. It is
expected that the two public meetings will occur one to
2 years apart.
Comment: Six commenters (IV-D-18, IV-D-31, IV-D-43,
IV-D-44, IV-D-85, IV-D-108) objected to the proposed public
hearing and review requirements because they are redundant of
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public review that already occurs. Two commenters (IV-D-43
and IV-D-44) argued that it is unnecessary to require a
hearing to discuss materials separation programs in the
context of an air permit. The commenters noted that hearings
are already conducted as part of the comprehensive planning
process and as part of the air permit process. The commenters
also argued that it is incorrect to assume that there would be
no public discussion or hearings in the absence of an EPA
mandate.
One commenter (IV-D-85) argued that the procedural
requirements of the proposed materials separation plan are
unnecessary and unrealistic because the initial decision to
build an MWC is part of a municipality's overall MSW
management plan. The commenter indicated that waste reduction
plans and regional MSW management planning are addressed in
State MSW management plans, including public participation
components, adopted since the 1984 amendments to RCRA.
According to the commenter, by the time that a facility is
applying for an air permit, all MSW management decisions will
have been made and there should be no need for additional
public hearings on the issue.
One commenter (IV-D-108) opposed the public participation
provisions because they are already conducting public hearings
and have developed solid waste advisory councils at the State
level. Therefore, the proposal would impose a redundant layer
of Federal requirements, according to the commenter.
One commenter (IV-D-18) objected to the proposed
materials separation requirements because they are redundant
to State solid waste management planning requirements,
including public participation, implemented since the 1984
amendments to RCRA.
Response: Hearings and meetings are already conducted as
part of the air permit process. In fact, the siting
requirements were developed to mimic the existing NSR
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requirements, such that the public meeting to cover the siting
analysis could be the same hearing required as part of the
State's permitting process. However, there is nothing in the
NSPS that would preclude an owner or operator of a proposed
MWC from combining the materials separation plan or siting
analysis public meetings with any other public meeting
required as part of another Federal, State, or local permit
review process, as long as two separate meetings are held, one
to focus on the materials separation plan and one to focus
primarily on the siting analysis. The owner or operator would
still be required to comply with the notification and comment-
response documentation requirements of the NSPS.
The siting requirements of the NSPS contain no provisions
affecting the relative timing of the air permitting process
and the completion of the materials separation plan. The NSPS
only requires that the final siting analysis and the materials
separation plan be submitted with or before the initial
application for construction permit. This provision will not
present a delay in the permitting process except for those
owners or operators that would have otherwise submitted a
construction permit application immediately after the
effective date of the NSPS.
If a municipality has already had public hearings to
decide on an overall MSW management approach, then this
approach may be considered at the public meetings, and
incorporated into the materials separation plan. The process
of making this decision and incorporating an existing plan
into the materials separation plan is not a significant
burden. In any event, the construction of a MWC would be a
significant new component in most areas' MSW management
programs. In such a case, existing material separation or
recycling programs should be reviewed and updated to
accommodate the development of the MWC as a new component in
an area's ISWM program.
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4.2.5 Legal Authority to Issue Materials Separation Plan
Requirements
Comment: The EPA received a number of comments (IV-D-28,
IV-D-37, IV-D-38, IV-D-41, IV-D-43, IV-D-44, IV-D-55, IV-D-56,
IV-D-67, IV-D-85, IV-D-87, IV-D-97, IV-D-98, VI-B-02, VI-B-04,
VI-B-05, VI-B-06) challenging the proposed materials
separation ("MS") plan as both being inconsistent with
Congressional intent and lacking statutory authority. Some of
these commenters argued that a MS program requirement is not a
siting requirement, nor has the EPA demonstrated that site
specific reductions will be achieved with MS. Some commenters
noted that the EPA has consistently concluded that MS programs
do not improve MWC emissions and there is no new data to
contradict this long-standing conclusion. Some commenters
argued that MS is a component of an integrated solid waste
management system, and such systems should be promulgated
under the Resource Conservation and Recovery Act ("RCRA") and
applied to all solid waste facilities, not promulgated under
the CAA and applied only to MWC's. Some of the comments
further stated that the legislative history of the Act clearly
indicates Congress' intent not to include MS and recycling in
the CAAA, because the Senate version of the 1990 Amendments
containing these provisions subsequently was removed by the
Conference Committee based upon the Committee's belief that it
would be better to regulate solid waste issues comprehensively
under RCRA. Some commenters stated that adding a MS program
violates Executive Order 12875, and further, MS is not an
emission control technique and section 129 only authorizes
performance standards and other requirements, such as
numerical emission limits or monitoring requirements.
Response: The EPA disagrees with the commenters who
argued that it lacks statutory authority to promulgate
materials separation as a procedural requirement that owners
and operators of new MWC's must meet as part of the siting
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analysis. Authority for this action is derived from
sections 129(a) (3), 129(a)(2), and 111 (a) (1) .
Section 129(a)(3) provides that MWC standards shall be based
upon methods and technologies "for removal or destruction of
pollutants before, during, or after combustion . . .." 42
U.S.C. § 7429(a) (3) (emphasis added) . Section 129(a) (2)
authorizes the Administrator to take into consideration a
number of factors, including "any non-air quality health and
environmental impacts and energy requirements . . .." 42
U.S.C. § 7429(a)(2) (emphasis added). Section 111(a)(1)
similarly requires promulgated standards to reflect "any
nonair quality health and environmental impact and energy
requirements . . .." 42 U.S.C. § 7411(a)(1).
The Administrator concludes that separating materials
before combustion will result in fewer materials containing
pollutants being combusted, which means there will a decrease
in pollutants emitted, since no emission control system has
demonstrated the capability of removing 100% of the HAP's
contained in materials that are burned in MWC's. Moreover,
recycling of materials conserves natural resources. For
example, the more aluminum cans that are recycled, the less
bauxite (a mineral from which aluminum is made) is needed,
thereby providing a positive environmental impact. Therefore,
the Administrator decided to retain the materials separation
requirement in essentially the same format proposed. As part
of the siting analysis for new units, owners and operators
must submit a materials separation plan for public review and
comment prior to obtaining a construction permit. The
materials separation requirement is procedural in nature only;
no specific performance levels, specification of separation
system design, or designation of materials to be separated are
required in the final rule. The final rule thus allows the
materials separation plan to be specifically tailored to the
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area to be serviced by the MWC as one method to be considered
for removing pollutants before combustion.
4.2.6 Overall Acrencv Strategy to Promote Municipal Solid
Waste Reduction and Recycling
Comment: Several commenters (IV-D-18, IV-D-28, IV-D-43,
IV-D-44, IV-D-56, IV-D-67, IV-D-120, VI-B-02, VI-B-05,
VI-B-06) concluded that a materials separation program is not
an appropriate requirement of an air quality regulation. The
commenters stated that materials separation would be more
effectively instituted if applied to all MSW management
activities in a comprehensive program under RCRA, rather than
in a piecemeal fashion. One commenter (IV-D-98) added that
the proper sizing of an MWC plant must be determined through
comprehensive MSW management planning addressed on a
State-wide basis under RCRA and that the NSPS would perpetuate
piecemeal MSW regulation, which is what Congress sought to
avoid.
Response: The materials separation plan provisions of
the NSPS are a procedural requirement to evaluate the effect
of current and projected material separation and recycling
activities on the quantity and character of MSW in the service
area of the MWC. The information obtained in the development
of the materials separation plan will be used to ensure that
the MWC is of the proper size for the service area. Since the
size of the MWC will affect the magnitude of the air quality
impacts from the MWC, the materials separation plan is an
appropriate consideration under the siting requirements
required by the Act.
The NSPS does not prescribe what separation or recycling
activities should be performed in the service area of the MWC.
Therefore, the NSPS does not attempt to accomplish any
specific MSW management goals that should be addressed on a
State-wide basis under RCRA.
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Comment: Two commenters (IV-D-28, IV-D-44) urged the EPA
to review the regulatory agenda for other MSW management
approaches to enable a "level playing field" to be achieved
for all MSW management practices. According to one commenter
(IV-D-28), regulating MSW management in a piecemeal fashion by
requiring materials separation for MWC's may bias decisions
made at the local government level with no assurance for the
protection of public health and the environment. Refer to
section 3.6.1 for further discussion of the environmental
impact of landfills versus MWC's. The other commenter
(IV-D-44) noted that the EPA concluded in the preamble to the
1991 NSPS (subpart Ea) that it should not promulgate
requirements for material separation programs that
discriminate against MWC's and favor landfills (56 FR 5497).
Response: The NSPS does not require any specific
materials separation or recycling programs that would
discriminate against MWC's in favor of landfills. The NSPS
only requires that owners and operators of a proposed MWC
consider the effect of present and future material separation
or recycling programs on the quantity and character of MSW
and, in turn, the projected size of the MWC.
Section 3.6.1 discusses the potential impact of the
entire NSPS on the selection of landfills versus MWC's and the
potential environmental impacts of the decreased use of MWC's
in favor of landfills.
4.2.7 Miscellaneous
Comment: One commenter (IV-D-24) noted that the Court of
Appeals decision in New York v. Reilly, 969 F. 2d 1147, 1153
(D.C. Cir. 1992) stated that the EPA has concluded that
removal of lead-acid batteries reduces emissions. The
commenter urged the Agency to ban the combustion of lead-acid
batteries in the final rule. The commenter also noted that
because the EPA is under a court order to promulgate the MWC
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regulations, the EPA must decide the materials separation
issues within the deadlines set by the court order.
Response: The EPA's final decision on the issue of
separating lead-acid batteries from MSW destined for MWC's
will be addressed in a separate EPA action to be published at
the same time as the final NSPS and emission guidelines. That
action will reflect considerable information on the effect of
lead-acid batteries on MWC emissions the recycling of lead-
acid batteries that the EPA has collected since the Court of
Appeals decision.
Comment: One commenter (IV-D-99) stated that local
governments with MWC's already have some of the best recycling
programs in the country. The commenter argued that if the EPA
wants to require materials separation, materials separation
should be added to standards for landfills, instead of to the
requirements for MWC's.
Response: The materials separation plan provisions of
the NSPS will apply only to new MWC's and not to existing
MWC's. Furthermore, the NSPS does not require materials
separation, only an evaluation of the effect of materials
separation and recycling on the projected quantity and
character of MSW generated in the service area of the MWC.
Actual MSW recycling and material separation requirements
addressed under RCRA.
Existing recycling and materials separation programs in
the service area of a proposed MWC can serve as the starting
point for the materials separation plan. To comply with the
NSPS, the owners or operators of the proposed MWC only need to
reassess the existing program in light of the proposed MWC and
provide for a public meeting and the opportunity for public
comment on the materials separation plan.
Comment: Two commenters (IV-D-75, IV-D-96) argued that
materials separation plans are local concerns that are better
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addressed by local solid waste management plans and
regulations than by Federal air pollution control regulations.
Response: Procedural requirements for a materials
separation plan were proposed on the Federal level to ensure
that all States and municipalities consider materials
separation and recycling in the siting of new MWC's. A
majority of municipalities have addressed materials separation
and recycling at the local level. The NSPS includes materials
separation plan provisions so that materials separation and
recycling are considered in the siting of all new MWC's.
However, local factors affecting materials separation and
recycling are variable; therefore, no specific materials
separation ore recycling activities were included in the NSPS.
The actual details of each plan and the activities to be
undertaken will be left to the owners and operators, local
governments, and those participating in the public meetings.
Under the NSPS program, State and local agencies are delegated
the authority to implement and enforce the NSPS. Therefore,
State and local agencies, rather than the Federal EPA, will
typically be involved in the materials separation plan and
siting procedures.
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5.0 NEW SOURCE PERFORMANCE STANDARDS -
FUGITIVE ASH EMISSIONS
5.1 SELECTION OF FUGITIVE ASH EMISSION LIMITS
Comment: Several commenters (IV-D-02, IV-D-18, IV-D-28,
IV-D-30, IV-D-34, IV-D-37, IV-D-38, IV-D-41, IV-D-43, IV-D-44,
IV-D-67, IV-D-69, IV-D-82, IV-D-85, IV-D-98, IV-D-99, IV-B-02,
IV-B-06) contended that from a practical standpoint, zero
emissions is not achievable. Three commenters (IV-D-18,
IV-D-82, and IV-D-85) were concerned that any observed
emission, regardless of its nature, size, and duration would
need to be reported as a violation, and could be subject to
penalties and fines. Some commenters (IV-D-18, IV-D-28,
IV-D-85, IV-D-98) added that because Method 22 requires
records of visible emissions of 0.5 second durations, a zero
emission limit will be unachievable. Some commenters
(IV-D-18, IV-D-30, IV-D-37, IV-D-38, IV-D-44, IV-D-85)
concluded this standard would prevent an operator from ever
opening any enclosed ash system where ash could potentially
become fugitive, and would prevent necessary maintenance
activities. Three commenters (IV-D-18, IV-D-85, IV-D-98) gave
examples of fugitive emission generating activities that may
violate the zero emission standard or guideline, including
routine changing of FF's and other maintenance activities.
Three commenters (IV-D-37, IV-D-38, IV-D-44) were concerned
that a zero visible emission guideline allows no leeway for
emissions from accidental releases, spills, or equipment
failure or maintenance, and urged the EPA to provide an
exception for such situations.
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Several commenters (IV-D-18, IV-D-43, IV-D-44, IV-D-67,
IV-D-85) contended that EPA's observation of three MWC plants
and Method 22 testing of two MWC plants does not constitute a
representative sample and is not sufficient to conclude that a
zero emission standard or guideline can be met. One commenter
(IV-D-99) said they were not aware of any scientific or
technical justification for the zero emissions limit.
Thee commenters (IV-D-47, IV-D-49, IV-D-74) supported the
proposed fugitive ash emission limit.
Response: The proposed no visible emissions limit was
based on observations of ash handling practices at several
MWC's and visible emissions data from two MWC plants. Since
proposal, the EPA has reviewed Method 22 visible emissions
data from the metallic mineral and nonmetallic mineral
processing industries, which use similar transfer systems.
The data show visible emissions from conveyor transfer points
and transfer points from 0 to 2.5 percent of the time. Based
on consideration of the comments received and this additional
fugitive emissions data, the EPA revised the no visible
emission limit to be a visible emission limit of less than
5 percent of the time from ash conveying and transfer systems
and ash storage. This limit provides a reasonable margin to
ensure that the level is achievable.
Additionally, the final standards include an exemption
from the fugitive ash visible emission limit for maintenance
and repair activities, because these necessary activities may
require opening of an enclosure that could generate short-term
visible emissions.
5.2 FORMAT OF FUGITIVE ASH STANDARDS
Comment: Several commenters (IV-D-18, IV-D-28, IV-D-30,
IV-D-43, IV-D-44, IV-D-54, IV-D-56, IV-D-75, IV-D-80, IV-D-85,
IV-D-95, IV-D-103) suggested that work practice standards and
guidelines should be used to regulate MWC fugitive ash instead
of a zero emission limit standard.
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Response: Under section 111(h)(1), the EPA only may
promulgate a work practice standard if the Administrator
determines it is not feasible to prescribe or enforce a
standard of performance. The Administrator believes, however,
that the final rule's visible ash limitation is both
achievable and enforceable. Accordingly, work practice
standards are not authorized to control visible ash emissions.
5.3 LEGAL AUTHORITY TO PROMULGATE FUGITIVE ASH STANDARDS
Comment: Two commenters (IV-D-28, IV-D-69) contended
that the proposed fly ash/bottom ash rules are outside the
purview of the Act. These commenters and others (IV-D-41,
VI-B-02, VI-B-06) characterized the proposed fugitive ash
limit as arbitrary and outside the EPA's regulatory latitude.
One commenter (IV-D-18) contended that the EPA has no
authority to regulate indoor emissions, and is exceeding its
authority by proposing zero emissions "at the doorway" instead
of at the fenceline. Another commenter (IV-D-98) stated that
the EPA has no legal authority to regulate ash under
section 129; rather, section 129 is intended to control
pollutants from MWC combustion processes, not fugitive
emissions from post-combustion residues. The commenter
further contended that section 129 regulates "MWC units,"
which the Act defines as a distinct operating unit of any
facility which combusts solid waste, and ash collection and
storage facilities do not fall within the definition of MWC
units.
This commenter (IV-D-98) also argued that the legislative
history precludes the EPA from regulating fugitive ash
emissions under section 129. The commenter contended that the
Conference Committee deleted the provisions that would have
authorized regulation of ash fugitives under section 129,
believing that ash handling should be regulated under RCRA.
The same commenter further contended that unlike
section 112(d), section 129 does not expressly authorize the
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EPA to require enclosure of systems, collection, capture or
treatment of fugitive emissions, or design or work practice
standards. The commenter concluded from these omissions in
section 129 that the EPA is not authorized to regulate
fugitive ash emissions from MWC's.
Another commenter (IV-D-85) stated that section 111,
which is referenced in section 129, authorizes the EPA to
issue work practice standards in lieu of performance standards
where performance standards are not feasible. The commenter
suggested that the EPA promulgate such work practice standards
to regulate ash emissions. Two commenters (IV-D-37, IV-D-38)
further stated that the proposed ash zero-emissions standard
was impossible to achieve, and thus, was arbitrary and
capricious.
Response: The legal issues raised by these comments are
addressed below.
Scope of Coverage
As noted by some commenters, section 129(a)(1) authorizes
the EPA to establish standards for solid waste incinerator
units, which section 129(g) defines as a "distinct operating
unit of any facility which combusts any solid waste material
from commercial or industrial establishments . . .." 42
U.S.C. § 7429(g) (emphasis added). This definition of solid
waste incinerator unit, however, does not clearly define the
boundaries of a solid waste incinerator unit, particularly
since the word, "unit," is included in the definition. As a
result, the EPA has received requests for clarification
regarding the appropriate boundaries of a solid waste
incinerator unit. (These questions typically arise in the
context of a potential modification/reconstruction, because in
determining whether NSPS applies to an existing unit, one of
the key factors is the cost to modify or reconstruct the
combustor.) To avoid further confusion, the final rule
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clarifies the boundaries of a solid waste incinerator unit to
which these regulations apply.
Under the final rule, a solid waste incinerator unit is
defined as the MWC combustor, which includes, but is not
limited to, the fuel feed system, grate system, flue gas
system, bottom ash system, and the combustor water system.
Generally speaking then, the combustor starts at the MSW pit
or hopper and extends through (1) the combustor flue gas
system, which ends immediately following the heat recovery
equipment, or if there is no heat recovery equipment,
immediately following the combustion chamber; (2) the
combustor bottom ash system -- including all ash handling
systems that are interconnected to the bottom ash handling
system -- which ends at the truck loading station or similar
ash handling equipment that transfers ash to final disposal;
and (3) the combustor water system, which starts at the feed
water pump and ends at the piping exiting the steam drum. The
combustor does not include air pollution control equipment,
the stack, water treatment equipment, or the turbine-generator
set.
The final fugitive ash emissions rule is thus limited to
emissions from the combustor, as defined above. It does not
cover emissions from trucks and storage facilities since these
are outside the combustor unit.
Additionally, the EPA agrees with the commenters that
this rule should not regulate indoor emissions of fugitive
ash. It was the EPA's original intent that the fugitive ash
emission limit apply to external ash emissions. If ash
handling equipment subject to the rule is enclosed inside a
building or other enclosure, the fugitive ash emission limit
would apply to visible emissions discharged from the building,
not visible emissions inside the building. The final rule has
been revised to clarify this point.
Legal Authority to Regulate Ash Emissions
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The EPA disagrees with those commenters who stated that
the EPA does not have the discretion under section 129 to
regulate fugitive ash/bottom ash emissions. As stated in the
subsection above, the final rule regulates ash emissions from
the combustor bottom ash system, as well as any ash emissions
from all ash handling systems that are interconnected to the
bottom ash handling system prior to the truck loading station
or similar ash handling equipment that transfers ash to final
ash disposal. The legal authority for this standard is
provided in sections 129(a)(3) and 129(a)(4).
Section 129(a)(3) states:
(3) Control methods and technologies
Standards under section 7411 of this title and this
section applicable to solid waste incineration units
shall be based on methods and technologies for removal or
destruction of pollutants before, during, or after
combustion ....
42 U.S.C. § 7429(a) (3) (emphasis added) . Section 129(a) (4)
further requires the EPA to:
[S]pecify numerical emissions limitations for the
following substances or mixtures: particulate
matter (total and fine), opacity (as appropriate),
sulfur dioxide, hydrogen chloride, oxides of
nitrogen, carbon monoxide, lead, cadmium, mercury,
and dioxins and dibenzofurans. The Administrator
mav promulgate numerical emissions limitations or
provide for the monitoring of postcombustion
concentrations of surrogate substances, parameters
or periods of residence time in excess of stated
temperatures with respect to pollutants other than
those listed in this paragraph.
42 U.S.C. § 7429(a)(4) (emphasis added).
Fugitive bottom ash emissions are emissions of dust from
the combustor bottom ash system that are not contained within
a fully enclosed ash handling system. This bottom ash dust
consists of PM and various associated pollutants absorbed to
the PM, such as Cd, Pb, Hg, and organic compounds, including
dioxins and furans. Thus, the EPA properly can regulate
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fugitive bottom ash emissions because (1) they are emitted by
an MWC unit; (2) they consist of a mixture of the pollutants
expressly listed in section 129(a)(4) for which the EPA is
required to specify numerical emissions standards; and (3) the
standards are "based on methods and technologies for removal
. . . of [these] pollutants [from the air] . . . after
combustion . . 42 U.S.C. § 7609(a)(3).
Section 112 Enumerated List of Methods
One commenter (IV-D-98) noted that section 112(d)(2)
expressly states that in promulgating section 112 emissions
standards, the EPA may apply:
[M]easures, processes, methods, systems or techniques
including, but not limited to, measures which . . .
(A) reduce the volume of, or eliminate
emissions, of, such pollutants through process
changes, substitution of materials or other
modifications,
(B) enclose systems or processes to eliminate
emissions,
(C) collect, capture or treat such pollutants
when released from a process, stack, storage or
fugitive emissions point,
(D) are design, equipment, work practice, or
operational standards (including requirements for
operator training or certification) as provided in
subsection (h) of this section, or
(E) are a combination of the above.
42 U.S.C. § 7412(d)(2). The commenter stated that because
section 129(a)(2), which contains language that is similar to
the rest of section 112(d)(2), does not contain this
enumerated list, Congress did not intend to give the EPA the
discretion to consider these methods when developing MWC
standards.
The EPA disagrees with the conclusions reached by this
commenter. The fact that section 129 does not include a list
that is identical to sections 112(d)(2)(A)-(D) does not
mean, a fortiori, that the EPA is precluded from promulgating
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such measures, processes, methods, systems or techniques under
section 129. Unlike section 112 standards, MWC standards are
promulgated under both section 129 and section 111. See
section 129(a)(2) and 129(b)(1). Thus, Congress did not need
to include language in section 129 that already was
incorporated, either expressly or impliedly, in section 111.
For example, section 111(h)(1) states in pertinent part:
Design, equipment, work practice, or operational
standard; alternative emission limitation
(1) For purposes of this section, if in the
judgment of the Administrator, it is not feasible to
prescribe or enforce a standard of performance,
Lslhe mav instead promulgate a design, equipment,
work practice, or operational standard, or
combination thereof, which reflects the best
technological system of continuous emission
reduction which (taking into consideration the cost
of achieving such emission reduction, and any non-
air quality health and environmental impact and
energy requirements) the Administrator determines
has been adequately demonstrated.
42 U.S.C. § 7411(h)(1) (emphasis added). As this example
demonstrates, Congress did not need to include in section 129
a provision that is analogous to section 112(d)(2)(D) [work
practice standards] because this authority already exists in
section 111(h)(1).
Moreover, section 129(a)(3) expressly gives the EPA the
authority to promulgate standards based on "methods and
technologies for removal or destruction of pollutants before,
during, or after combustion . . .." 42 U.S.C. § 7429(a) (3)
(emphasis added). Thus, although Congress did not expressly
list examples of methods and technologies that the EPA may
consider in promulgating section 129 standards as it did in
section 112(d)(2) for section 112 standards, section 129(a)(3)
vests the EPA with the discretion to determine upon which
methods and technologies it should base MWC standards. It
should also be noted that section 112 does not have a
provision comparable to section 129(a)(3), but this does not
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mean that the EPA cannot consider methods and technologies for
removal or destruction of section 112 pollutants when it sets
section 112 standards. Rather, it appears that Congress gave
the EPA discretion in both section 129 and section 112 to
promulgate standards based upon methods and technologies for
removing pollutants: in section 129(a)(3), it gave this
discretion in broad terms; whereas in section 112(d)(2),
Congress provided some specific examples of the methods the
EPA could consider. Accordingly, the final ash emissions rule
promulgated today, which is based on methods and technologies
for removal, after combustion, of many of the pollutants that
the EPA is required to regulate under section 129, is a proper
exercise of the EPA's discretion.
Legislative History
The EPA also does not agree that the legislative history
precludes it from promulgating a numerical ash emissions
standard. The Senate Bill, as reported, contained recycling
and ash management requirements that ultimately were deleted
by the Conference Committee. Read in context, however, it
appears that Congress was concerned with deleting ash disposal
requirements from section 129; the history does not suggest
that Congress intended to prevent the EPA from exercising its
discretion to remove ash emissions from the air. This point
is demonstrated by the Senate Report's comments regarding the
proposed title Ill's ash provisions:
In addition to new authorities to control emissions
of hazardous air pollutants and to prevent
catastrophic chemical accidents, title III also
provides for the control of air emissions and
management of ash disposal from municipal waste
incineration units.
Incinerators have come to the forefront in the
solid waste disposal industry because the quantity
of the waste generated continues to increase while
landfill disposal capacity declines. . . . The fly
ash which is produced by the emission control
systems may or may not be mixed with the bottom ash.
But both are ultimately disposed in landfills.
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Lea. Hist, at 8484, 8486 (emphasis added).
Further, during the Senate debates on the 1990 CAAA
Conference Report, Senator Dole stated that the EPA should be
addressing in the new source performance standards for MWC's a
number of the critical issues that were eliminated from the
conference report:
Another area of concern to me is the treatment of
solid and medical waste incinerators under the bill.
. . . Although the bill has been improved, there are
still critical issues that were eliminated from the
conference agreement and will have to be worked out
in the new source performance standards. It is my
view that the EPA should look to clean,
environmentally sound incineration techniques,
recycling and ash management as kev components of
national waste management policy.
Leg. Hist, at 1974 (Oct. 27, 1990) (statement of Sen. Dole)
(emphasis added).
Thus, whatever Congress may have intended with respect to
the EPA's discretion to regulate disposal of ash from MWC's,
Congress did not eliminate the EPA's discretion to regulate
emissions of ash from MWC's to the air. Thus, the proposed
and final rules properly limit the amount of fugitive bottom
ash that owners and operators of MWC's may emit into the air;
it does not regulate how the collected ash is to be disposed
of.
Achievabilitv of Standard
The EPA has considered the comments of those who stated
the proposed standard is impossible to achieve, and thus, is
arbitrary and capricious. As discussed in section 5.1, the
final standards allows fugitive ash emissions up to 5-percent
of the time that the test is being conducted. The EPA's data
demonstrate that commercial MWC's are capable of meeting this
standard with an ample margin, thereby demonstrating the
achievability of the standard. The final rule also has been
revised to apply only during the operation of the combustor
unit in order to address the concerns raised that certain
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maintenance operations, such as changing the baghouse filters,
will generate visible ash emissions. The EPA thus believes
the final rule is both achievable and a well-reasoned way of
controlling emissions of the pollutants designated in
section 129(a)(4) after combustion.
5.4 MISCELLANEOUS
Comment: Some commenters (IV-D-18, IV-D-30, IV-D-56,
IV-D-80, IV-D-85, IV-D-87, IV-D-95) were concerned that
Method 22 is subjective and subject to error. Three
commenters (IV-D-18, IV-D-30, IV-D-85) said that Method 22
does not require the observer to be certified (as does
Method 9). Other commenters (IV-D-18, IV-D-30, IV-D-56,
IV-D-67, IV-D-80, IV-D-95) said that ambient conditions,
steam, or fugitive non-ash emissions may interfere with
observations and introduce error. One commenter (IV-D-75)
said that dust and other PM from surrounding properties can be
transported on site during high wind "Santa Anna" conditions
and could easily be mistaken for MWC fugitive ash.
Three commenters (IV-D-18, IV-D-28, IV-D-85) said the
standard, as written, assumes any dust emitted from an ash
area is ash, whereas some MWC plants store hydrated lime or
activated carbon in areas also used for conveying ash. The
commenters said that a fugitive emission of activated carbon
should not constitute a violation of the fugitive ash
standard.
Response: A Method 22 observer is required to complete
Method 9 training, but is not required to be certified for
Method 9. Method 9 is a more difficult method that involves
observing opacity and making a judgement about the percent
opacity of emissions, whereas Method 22 is an observation of
the amount of time any visible emissions are observed. It is
for this reason that Method 9 certification is not required.
Method 9 training is adequate for Method 22 observers because
it trains the observer about the principles of observing
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visible emissions. Method 9 training includes training for
the observer to distinguish between emissions and steam.
While the training does not specifically address the
interference of non-ash fugitive emissions, observers are
trained in considering their location with respect to the
source of emissions and it is expected that observers are
trained in considering their location with respect to the
source of emissions and it is expected that observers will use
common sense in distinguishing between the source of
emissions.
Comment: One commenter (IV-D-31) suggested that the EPA
clarify that their reference to "ash pile usage, mixing of fly
ash with bottom ash, and addition of stabilizers of binders"
(on p. 48222 of the proposal preamble) is not to be
interpreted as sanctioning by the EPA of any of these
activities when the ash qualifies as a hazardous waste. The
commenter noted that activities used to comply with the
fugitive ash provisions of the NSPS or emission guidelines
must be in compliance with RCRA regulations.
Response: The commenter is correct in stating that
activities used to comply with the fugitive ash provisions of
the NSPS or guidelines must also be in compliance with any
RCRA regulations that apply to the MWC.
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6.0 MISCELLANEOUS COMMENTS ON MUNICIPAL WASTE COMBUSTOR
NEW SOURCE PERFORMANCE STANDARDS
6.1 HEALTH EFFECTS OF DIOXINS/FURANS AND MERCURY
Comment: Five commenters (IV-D-17, IV-D-24, IV-D-65,
IV-D-122, IV-D-126) discussed the health effects of
dioxins/furans and/or mercury. Three commenters (IV-D-17,
IV-D-24, IV-D-65) discussed the health effects of metals and
their implication on the NSPS and emission guidelines. Two
commenters (IV-D-17, IV-D-65) pointed out that metals can be
passed through the food chain causing adverse health effects.
One commenter (IV-D-17) argued that the strictest possible
emission limits for Hg are warranted. The commenter pointed
out that Hg can be passed from mother to fetus and infant.
The commenter further stated that Hg also bioaccumulates in
the aquatic food chain such that fish can carry Hg
concentrations in their flesh up to a million times higher
than those found in the water, and that therefore families,
including Native Americans, and wildlife that feed on fish are
at risk. The commenter stated that deposition of airborne Hg
from anthropogenic sources is responsible for accumulation of
Hg in the aquatic food chain. The commenter cited an EPA
study that estimates that MWC's and MWI's account for more
than 128.5 tons/yr or more than 38 percent of the total
anthropogenic emissions. The commenter claimed that MWI's
represent about half of this total.
One commenter (IV-D-65) argued that EPA's proposed
standards fail to address food chain implications properly and
that ash which is utilized adjacent to soil should be
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regulated "by content, by dry weight, as compost is regulated,
and not by leaching characteristics."
The commenter (IV-D-65) stated that leaching is a
relatively minor pathway into the food chain for most metals.
The commenter suggested that the "WES-PHix process", patented
by Wheelabrator Environmental Systems, which places
metal-laden ash near soil, is "another case of the EPA
appearing to guided by a vendor."
One commenter (IV-D-24) provided an article regarding Hg
contamination in the United States in order to stress the
importance of applying the proposed emission guidelines to MWC
"units" smaller than the 35 Mg/day size cutoff specified in
the proposal. Refer to section 3.2 for further discussion of
the comment regarding the smaller size cutoff.
Three commenters (IV-D-65, IV-D-122, IV-D-126) asserted
that the dioxin/furan limit is not strict enough and that the
EPA should recommend a ban on dioxin-producing incinerators.
The commenters claimed that humans are presently exposed to
levels which tend to cause unacceptable damage and that there
is no threshold of safety. The commenters warned that dioxin
is an extremely poisonous, stable compound which can be passed
through to a fetus and newborn from the mother. The
commenters listed several reproductive, developmental, and
cancerous effects, as well as effects on the immune system, of
tetra-chlorinated dibenzodioxin.
Response: This rule is a section 129 technology-based
standard. Congress abandoned the risk-based approach because
it was found to be ineffective. In the 1970's and 1980's
numerous technology-based standards were implemented under
section 111 as compared to only a few risk-based standards
under section 112. It is recognized that there are health
concerns associated with dioxins/furans and Hg. The final
emission standards and guidelines will significantly reduce
dioxin/furan and Hg emissions. Within 5 years of
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implementation of these rules, the EPA will conduct a risk-
based analysis.
6.2 PROCEDURAL
Comment: Six commenters (IV-D-01, IV-D-78, IV-D-46,
IV-D-61, IV-D-79, IV-D-93) requested 30-day extensions to
develop adequate and meaningful comments to the NSPS and
emission guidelines. Reasons provided by the commenters
included the following: (1) The provisions dealing with
"applicability" of co-fired combustion units and cement kilns
were causing considerable confusion; (2) EPA's three-part
proposal is very complex and the proposal requested comment on
a variety of issues, including cost analysis; (3) the
inability to obtain a copy of the draft regulatory language in
a timely manner as it was not published in the Federal
Register; and (4) the applicability of the proposed rule is
broad enough to have a significant effect on RCRA policy,
other regulations, and future rule-makings on medical and
industrial waste combustors.
Response: The public comment period officially remained
open until November 21, 1994 as originally scheduled.
However, the public comment period was effectively longer than
60 days. The MWC regulations were published (proposed) in the
Federal Register on September 20, 1994, and the 60-day comment
period remained open until November 21, 1994. Prior to
proposal, various drafts of the regulations were circulated
widely including distribution to MWC owners, MWC operators,
State governments, and environmental groups. The last
circulated draft was in mid-August 1994 two weeks prior to
signature of the proposal. Additionally, the full text of the
final regulations (preamble, regulations, and Fact Sheets)
were entered into the EPA Technology Transfer Network (TTN)
electronic bulletin board on September 2, 1994, the day after
signature of the proposal, making the actual proposal
available to the public almost 3 weeks before publication in
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the Federal Register. Although the public comment period
ended November 21, 1994, comments continued through April
1995. As noted in chapter 2.0, 35 percent of the public
comment letters considered by EPA were received after the
November 21 deadline.
Comment: Five commenters (IV-D-35, IV-D-57, IV-D-61,
IV-D-93, IV-D-102) complained about the practice of not
publishing NSPS and emission guidelines rule language in the
Federal Register. One commenter (IV-D-35) stressed that this
practice is "disturbing" given the "importance" of the precise
rule language, and since the electronic copy cannot be
verified. One commenter (IV-D-61) reported that it took them
several weeks to obtain the necessary information from the
proper sources. This commenter continued that this practice
is "unfortunate" because it has increased the burden on the
regulated community to access the information necessary to
provide comprehensive comments. One commenter (IV-D-102)
complained they could not comment on § 60.51b because the
section was not in the Federal Register.
Response: The EPA apologizes for any inconvenience
caused by its policy to not publish in the Federal Register
regulatory text for proposed rules. The regulatory text is
being provided on the EPA TTN rather than being published in
the Federal Register in order to reduce the costs of proposal
printing. The promulgation regulatory text was printed in the
Federal Register.
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7.0 EMISSION GUIDELINES - MUNICIPAL WASTE COMBUSTOR EMISSIONS
This chapter includes comments made specifically about
the proposed emission guidelines. To avoid duplication, when
the same comment was made about both the NSPS and emission
guidelines and the EPA's response to the comment is the same
for both the NSPS and guidelines, the issue is summarized only
once for both the NSPS and guidelines in chapter 3.0. If a
comment was made specifically regarding the guidelines and not
the NSPS, or if the EPA's response to the same comment is
different for the NSPS and guidelines, then the comment is
summarized and responded to in this section for the
guidelines. However, in those cases where the comment summary
or parts of the EPA's response are the same, to avoid
duplication, the comment summary and response may refer to the
summary and response in chapter 3.0 for more detail. This
chapter covers the following provisions: source category,
designated pollutant, modification and reconstruction, the
MACT floor and MACT, impacts, format of the emission limits,
performance test methods and monitoring requirements,
enforcement provisions, reporting and recordkeeping
provisions, malfunction provisions, legal considerations, and
wording.
7.1 SELECTION OF SOURCE CATEGORY
Comment: Two commenters (IV-D-19, IV-D-39) contended
that waste-fuel power generation facilities burning only clean
biomass materials should not be subject to the proposed
emission guidelines.
One of the commenters (IV-D-19) defined "clean biomass"
as including "bagasse from sugar cane processing operations,
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tree trunks and limbs from land-clearing activities, limbs and
wood waste from yard maintenance activities, wood pallets,
untreated lumber that has been removed from construction and
demolition debris from agricultural, residential,
institutional, and other areas throughout South Florida." The
commenter clarified that the term "bagasse" refers to a
fibrous, carbonaceous waste product resulting from the milling
of sugar cane.
The commenters were specifically concerned with the
Osceola and Okeelanta facilities currently under construction
in Florida, which will burn 100 percent clean biomass fuels
from both agricultural and residential/ institutional sources,
and which, as they are being built, will not be capable of
meeting the proposed guidelines for MWC metals, SO2, and CO.
The commenters pointed out that the EPA has decided that
sources firing agricultural biomass wastes would not be
subject to the proposal but that sources firing
residential/institutional biomass wastes would be subject to
the proposal. The commenters argued that the combustion of
those fuels will not be affected by the fuel's place of
origin. The commenters also pointed out that the EPA is
proposing that air curtain incinerators burning clean dry wood
should not be subject to the proposed emission guidelines for
solid waste incineration units. The commenters believed that
waste-fuel power generation facilities burning only clean
biomass materials should similarly not be subject to the
emission guidelines.
The commenters pointed out that if Osceola, Okeelanta,
and other biomass-fueled facilities were excluded from being
subject to the proposed emission guidelines, these types of
facilities would not be unregulated, as follows: (1) large
wood burning facilities will have to comply with PSD and other
air quality regulations, (2) cogeneration facilities will be
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subject to the NSPS in Subpart Da, and (3) new steam
generating units will be subject to subparts Db and Dc.
Response: As discussed in section 3.1, "clean wood" is
not included in the definition of MSW in the final rule. This
exemption was added to the final MWC rule for two reasons.
First, the EPA is developing regulations for combustion of
wood-fired boilers and industrial waste under separate
rulemakings. Second, test data for wood-fired boilers show
that the combustion of clean wood results in low dioxin/furan
and mercury emissions. Additionally, the EPA expects that
combustion of clean wood results in low emissions of other
pollutants such as lead and cadmium. Refer to section 3.1 for
more discussion of this rationale.
Clean wood is defined in the final rule as wood or wood
products including clean untreated lumber (which is defined in
the final rule), tree stumps, and tree limbs. Clean wood does
not include yard waste, which is considered to be MSW under
the final rule. Yard waste is defined in the final rule as
including grass, grass clippings, leaves, bushes, and shrubs.
By covering yard waste in the MWC rule, the EPA is encouraging
composting rather than the incineration of yard wastes.
One commenter requested that "bagasse" be considered to
be "clean biomass" and be exempt from the final rule.
Bagasse, as defined by the commenter, is a waste product
resulting from the milling of sugar cane. Because bagasse is
an agricultural waste from an industrial process, bagasse is
not considered a municipal waste, and is not included in the
definition of MSW. The EPA is currently considering the
regulation of agricultural and industrial wastes under a
separate rulemaking (see 59 FR 66850).
As a result of the removal of "clean wood" from the
definition of MSW, plants burning clean biomass consisting
only of "clean wood", wood pallets, and construction/
demolition wastes, as well as industrial process wastes and
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agricultural wastes would not be subject to the final MWC
rule. If these same plants combust less than 10 Mg/day or
less than 30 percent yard waste or other MSW on a unit basis
(making them cofired combustors under the final rule), the
plants would also not be subject to the final MWC rule, as
long as they submit an initial notification of exemption and
keep daily records of the amount of MSW combusted.
Comment: One commenter (IV-D-15) argued that the
definition of MSW should not include yard waste or other woody
debris because covering these materials under the MWC rule
will have a negative impact on city programs that sell the
material as fuel. The commenter explained that city programs
collect yard debris and trees/branches, intermix and shred the
material, and stockpile the material for composting or for
sell as fuel. The commenter explained that if the fuel is
considered MSW, it will not be marketable.
Response: As explained above, clean wood is exempt in
the final rule, but yard waste is still covered. The EPA
encourages composting rather than incineration of yard waste.
However, the material referred to by the commenter may still
be marketable as MSW under the final rule. As explained in
section 3.1 of this document, the definition of cofired
combustor was revised to allow plants that fire smaller
amounts of MSW (i.e., less than 30 percent MSW) to calculate
on a quarterly basis their usage of MSW to determine their
status as a cofired combustor. At proposal, combustion plants
were required to calculate MSW usage on a daily basis. See
section 3.1 for more discussion on this revision. This
provision may encourage buyers of the yard waste/clean wood
fuel to continue purchasing the fuel, as long as they qualify
as cofired combustors and are, thus, not considered MWC's and
not subject to the MWC rule.
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7.2 SELECTION OF DESIGNATED FACILITIES
Comment: One commenter (IV-D-7 6) requested that the
definition of MWC plant capacity be modified so that where
federally-enforceable permit conditions exist which limit the
maximum existing combustor plant capacity to less than
35 Mg/day, the emission reduction requirements of "this
section" would not be applicable. The commenter cited an
example of a two-unit plant where each unit has a capacity
less than 35 Mg/day and it is normal practice not to operate
more than one unit at a time. In this case, the commenter
argued, the effective capacity is less than the 35 Mg/day
threshold as long as there are federally-enforceable
conditions. The commenter recommended the third paragraph of
40 CFR 60.31b be modified to read as follows: "Municipal waste
combustor plant capacity means the aggregate municipal waste
combustor unit capacity to emit of all municipal waste
combustor units, taking into account any federally-enforceable
limitations on operations of or emissions from unit or units
at a facility for which construction, modification,..."
Response: It is appropriate to base NSPS applicability
on design capacity. All standards have been done this way
under section 111 for years. However, a new applicability
criteria has been added to the final NSPS and guidelines such
that if a plant is permitted to combust less than 10 Mg/day of
MSW or RDF, it is exempt. Federally-enforceable permit
conditions limiting the amount of MSW combusted by the whole
plant to less than 10 Mg/day must exist to qualify for this
exemption. The level of 10 Mg/day is consistent with the
proposed exemption for cofired combustors in the proposed
rule. Refer to section 3.1 for further discussion of this new
10 Mg/day applicability provision. As a result of this added
exemption, some of the plants referred to by the commenter are
now exempt from the final MWC NSPS and guidelines.
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7.3 MODIFICATION AND RECONSTRUCTION
Comment: One commenter (IV-D-04) stated the proposed
NSPS contained some potentially contradictory language
relative to the applicability of subparts Cb and Eb to a
modified existing source where modification costs exceed
50 percent of the original cost of the plant in current
dollars. The commenter cited section II.A of the NSPS
preamble, which states that modification of an existing MWC
plant to comply with the emission guidelines would not bring
an existing MWC under the NSPS. The commenter also cited
section IV.C, which defines a modified solid waste
incineration unit as one in which the cost of modification
exceeds the 50 percent threshold. The commenter then
questioned which section would govern if an existing plant
were to incur costs above the 50 percent threshold while
attempting to comply with subpart Cb.
Three other commenters (IV-D-28, IV-D-37, IV-D-38) said
it is unfair that extremely costly retrofits necessary to meet
the guidelines for existing sources might ultimately transform
an existing source into a new source and trigger NSPS. These
commenters requested the EPA exclude these costs from the
definition of a modified solid waste incineration unit.
Response: The intent is as specified in § 60.32b(h) of
the proposed guidelines, "Physical or operational changes made
to an existing municipal waste combustor unit solely for the
purpose of complying with emission guidelines under this
subpart are not considered modification or reconstruction and
do not bring an existing municipal waste combustor unit under
the provisions of subpart Eb of this part". If a plant were
to incur costs above the 50 percent threshold while attempting
to comply with subpart Cb, the plant would remain an existing
source and would not trigger NSPS. The citation listed above
from the proposed guidelines has been retained in the final
guidelines, with one minor exception. In the final rule, the
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provision cited above (under § 60.32b(c) of the final
guidelines and § 60.50b(d) of the final NSPS) was revised,
replacing the term "solely" to "primarily", to avoid a
situation where an existing facility, which makes
physical/operational changes to comply with the guidelines,
becomes subject to the NSPS because during the retrofit a
change was made (e.g., improving efficiency) that was not
directly related to compliance with the guidelines, but had a
secondary or associated benefit.
In the final rule, two new terms are defined to
incorporate the section 129 definition of "modified solid
waste incineration unit." The terms "reconstruction" and
"modification" (or "modified municipal waste combustor unit")
are defined to incorporate the section 129 definition of
"modified solid waste incineration." The definitions are
almost equivalent to the definitions of these two terms in
§ 60.14 and 60.15 of 40 CFR 60 subpart A.
7.4 SELECTION OF MAXIMUM ACHIEVABLE CONTROL TECHNOLOGY FLOOR
FOR MUNICIPAL WASTE COMBUSTOR EMISSIONS
7.4.1 General Comments on MACT Floor Selection
Comment: Several commenters (IV-D-18, IV-D-20, IV-D-30,
IV-D-44, IV-D-75, IV-D-68, IV-D-85, IV-D-90, IV-D-98,
IV-D-104, VI-B-11) criticized the EPA's approach of choosing
the average of the top 12 percent for existing sources
separately for each pollutant when determining the MACT floor
(this approach is referred to by the commenters as "cherry
picking"). The commenters asserted that no single plant can
achieve the best control level for all regulated pollutants as
determined by the EPA. Three commenters (IV-D-18, IV-V-85,
IV-D-98) said that "cherry picking" inevitably results in a
set of standards unachievable by any unit. One commenter
(IV-D-20) urged the EPA to re-evaluate the data to assure that
compliance is achievable simultaneously for all pollutants.
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Several commenters (IV-D-30, IV-D-68, IV-D-85, IV-D-90,
IV-D-98) pointed out that many pollutants are interrelated,
including the following: CO and N0X; PM, Cd, and Pb; SO2 and
HC1; PM and dioxins/furans; and CO and dioxins/furans. One
commenter (IV-D-30) said that an example is that higher
combustion temperatures reduce CO and dioxin/furan emissions
while increasing N0X emissions. Two commenters (IV-D-20,
IV-D-75) said that this approach does not account for site-
specific trade-offs in performance for multiple pollutants
from the same source. One commenter (IV-D-98) said that
permit limits take these trade-offs into account, but "cherry
picking" excludes from the MACT floor any consideration of
these factors.
Four commenters (IV-D-20, IV-D-90, IV-D-85, IV-D-98) said
that the EPA's approach is unlawful and that the Act commands
the EPA to look at the same 'best' existing source, or the
same best 12 percent of existing sources, to derive the entire
set of emission limitations that constitute the MACT floor.
The commenters cited Congressional record text in support of
this interpretation. Refer to section 3.11 for a discussion
of legal issues.
Response: The EPA agrees that many pollutants are
interrelated. The EPA considered these relationships in
selecting the MACT floor emission levels and MACT emission
limits for the regulated pollutants. The EPA determined what
APC technologies would generally be required to achieve the
MACT floor pollutant emission levels (i.e., SD/FF/ SNCR or
SD/ESP/SNCR for large plants; DSI/ESP for small plants). The
EPA then defined the performance capabilities of these
technologies in selecting the MACT emission levels.
Individual units with the same APC technologies will achieve
different emission rates, which is indicative of variability
within APC technologies. The EPA recognized this variability
within APC technology performance in establishing the MACT
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emission limits. The MACT floor pollutant emission levels for
existing units represent the upper bound of performance (i.e.,
the highest emission level) consistently achievable by the
specific APCD's determined to represent the MACT floor.
While there are limited data on SD/FF and SD/ESP used in
conjunction with SNCR, and there is some question as to
whether SNCR or carbon injection would affect the pollutant
emission levels for certain pollutants, data received by the
EPA after proposal indicate that the promulgated levels are
achievable. Data were received from units that recently
initiated operation with SD/FF/SNCR/carbon injection control
systems, and the data indicate that SNCR and carbon injection
do not interfere with the levels of control achieved by SD/FF.
Refer to the section 3.11 of this BID for the EPA's response
to legal issues raised by the commenters.
Comment: Two commenters (IV-D-68, IV-D-98) said that,
instead of "cherry picking", a better way to determine
achievable levels is to choose the best sources by adding the
weighted average of the rankings of the permitted emission
level of each individual pollutant from each source and
selecting the sources with the highest overall ranking.
Response: With regard to the suggested ranking approach,
the EPA does not think it is appropriate to distinguish
between similarly designed and operated APCD's (e.g.,
SD/FF's). This would be required if the actual emission
estimates were ranked as suggested by the commenters. It
would also be impossible to determine the single best source,
or the best group of sources, without assuming priority for
certain pollutants (one plant may have lower N0X emissions but
higher dioxin/furans). The lack of permit limits for some
individual pollutants at any given MWC and the problems with
how to prioritize or weigh permit limits for different
pollutants would make an overall ranking of existing sources
based on permit data infeasible. Instead, emissions data were
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used to examine the technical achievability of the MACT floor
and MACT emission levels for existing MWC's after the floor
was determined from the permit limits.
Comment: One commenter (IV-D-104) said that the EPA has
previously argued that "achieved by" does not require that all
sources in the top 12 percent meet the floor limits
(59 FR 29199, June 6, 1994). The commenter contended that
even under this interpretation, it must mean that at least
some of the best-performing sources must be able to meet the
MACT floors. The commenter said a review of table 2 of docket
item number II-B-37 from docket No. A-90-45 suggests that no
unit included in the EPA's data base can simultaneously meet
the floor developed for existing units for the individual
pollutants. One example is the Kent County MWC, which is in
the top 12 percent for Cd (at proposal, 12 percent of the
large plants included 29 units), but ranks fortieth for Pb,
thirty-seventh for HC1, one hundred and second for N0X,
thirtieth for S0X, and has no dioxin/furan limit.
Response: The MACT floor pollutant emission levels for
existing units were determined by the average emission
limitation of the top 12 percent of permitted units. Although
the permits were used to determine the MACT floor, the EPA
analyzed performance data to assess achievability. While a
plant may currently have a permit limit for a particular
pollutant that is less restrictive than the MACT floor or
emission limit for that pollutant in the final guidelines,
this does not mean that the plant cannot achieve lower levels.
For example, the commenter cited permit data from the Kent
County MWC. Although this MWC is ranked fortieth in terms of
permitted Pb emissions, performance data from both units at
this MWC indicate actual Pb levels of 0.007 mg/dscm at
7 percent O2 (see docket item number II-B-34 from docket
No. A-90-45). Such performance indicates that this plant
would not have difficulty in achieving the proposed Pb MACT
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floor level of 0.53 mg/dscm or the final Pb emission limit of
0.49 mg/dscm. Another example is the MWC located in Long
Beach, CA, which has achieved the MACT floor levels for all
pollutants (except Cd, for which no data were available).
Comment: Several commenters (IV-D-24, IV-D-49, IV-D-51,
IV-D-7 3, IV-D-7 4, IV-D-103, IV-D-104, IV-D-120, VI-B-11)
criticized the use of permit limitations for determining the
MACT floor. Three commenters (IV-D-51, IV-D-74, IV-D-103)
contended that the wording "emissions limitation achieved" in
section 129 of the Act refers to measured performance data
rather than permitted emissions.
Several commenters (IV-D-24, IV-D-49, IV-D-51, IV-D-73,
IV-D-74, IV-D-103, IV-D-104) criticized the MACT floor as
insufficiently stringent because "EPA derived its limitations
from permitted emission limitations only" and ignored actual
emission levels achieved in practice by the best performers.
These commenters challenged the EPA's interpretation of the
language of the Act and Congress's intent. One commenter
(IV-D-74) questioned the use of both permits and section 114
information requests as the basis for the proposed guidelines.
The commenter said the floor and guidelines should be based on
optimum control technology performance data, not permit
limitations or data from uncontrolled units. The commenter
recommended that the EPA use the same approach as was used in
establishing MACT floors and standards for new combustors
because they all have similar emissions and impacts on health
and the environment.
Several commenters (IV-D-18, IV-D-28, IV-D-30, IV-D-37,
IV-D-38, IV-D-44, IV-D-54, IV-D-56, IV-D-69, IV-D-80, IV-D-85,
IV-D-95, IV-D-98, IV-D-99) strongly supported the EPA's use of
permit limitations in setting the MACT floors for existing
plants. Several commenters (IV-D-13, IV-D-41, IV-D-43,
IV-D-67, IV-D-82, IV-D-96, VI-B-02, VI-B-03, VI-B-05, VI-B-06)
made the general statement that they considered EPA's
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"approach" to setting MACT floors for each pollutant to be
reasonable. Various commenters (IV-D-18, IV-D-28, IV-D-37,
IV-D-38, IV-D-44, IV-D-54, IV-D-56, IV-D-69, IV-D-80, IV-D-85,
IV-D-95,) asserted that the phrase "average emissions
limitation" in the Act clearly requires the EPA to use permit
limitations, not technology or emissions data.
Response: The EPA believes that permit limitations data
is appropriate to use in determining the MACT floors for
existing sources. See section 7.9 for discussion of the legal
issues raised by the commenters on this subject.
The EPA assures the commenters that although the MACT
floor emission levels are based on permit data, actual
emissions test data are considered for all pollutants in
determining the MACT level of control. For existing MWC units
at large MWC plants, the EPA is promulgating MACT emission
levels more stringent than the MACT floor emission levels for
Cd, Hg, and dioxins/furans. For existing MWC units at small
MWC plants, the EPA selected MACT emission levels more
stringent than the MACT floor emission levels for all
pollutants except PM and N0X. As such, MWC performance was
considered in establishing the emission guideline emission
limits, as had been done under previous regulatory efforts.
Comment: Six commenters (IV-D-18, IV-D-54, IV-D-74,
IV-D-80, IV-D-85, IV-D-104, IV-D-120) raised issues regarding
the quality of the permit data used. Two commenters (IV-D-18,
IV-D-85) pointed out that if a unit fails to meet its permit
limits on even a single occasion while being well-operated,
the limits cannot be considered in determining the MACT floor
because such limits are not demonstrated in practice to be
continuously achievable. Another commenter (IV-D-120)
questioned whether each plant is in compliance with its permit
limit, and if so, how close the limit is to the plant's actual
performance. One commenter (IV-D-104) warned that relying on
permitted emission rates precludes any real assessment of the
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compliance probability and may not even reflect reality if the
permit limits are not being met. One commenter (IV-D-85) said
the EPA should clarify the analysis it conducted of
performance against the permit limit by each unit for
inclusion of that unit in the MACT floor calculation. One
commenter (IV-D-74) criticized the EPA's approach of using
uncontrolled emission levels to fill in some of the data gaps
when determining the average top 12 percent, arguing that
using emissions data from uncontrolled units to determine MACT
limits is contrary to the objectives of the Act, which
requires continuous reduction of emissions based on MACT.
Response: The EPA agrees that it is important to
consider whether the units included in the top 12 percent have
met their permit limits. When evaluating the permit
limitation data, the EPA considered only those permit limits
that had been achieved by the respective plants. This was
determined by reviewing available test data for each plant and
contacting the State agencies issuing the permits.
Since proposal, the MACT floors for large and small
existing plants have been recalculated. The revisions
incorporate permit information received since proposal and an
updated inventory of MWC plants. The revised MACT floors for
existing MWC units at small MWC plants are 98 ppm SO2, 560 ppm
HC1, 67 mg/dscm PM, 1.1 mg/dscm Cd, 16 mg/dscm Pb, 1.2 mg/dscm
Hg, 1,500 ng/dscm dioxins/furans, and uncontrolled for NOx.
The revised MACT floors for existing MWC units at large MWC
plants are 31 ppm SO2, 31 ppm HC1, 24 mg/dscm PM,
0.097 mg/dscm Cd, 0.49 mg/dscm Pb, 0.27 mg/dscm Hg, and
126 ng/dscm dioxins/furans. The MACT floors for NOx were
revised based on subcategorization by combustor type:
200 ppmv for mass burn waterwall combustors; 250 ppmv for
refuse-derived fuel combustors; 250 ppmv for mass burn rotary
waterwall combustors; 240 ppmv for fluidized bed combustors;
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uncontrolled for mass burn refractory combustors; and 200 ppmv
for other combustors not listed above.
When necessary, the EPA did use typical uncontrolled
emission levels for MWC's in calculating the MACT floor in
instances where there were not enough data from units with
permit limitations to comprise the top 12 percent. For large
plants, this only occurred for Cd; however, the emission limit
in the final guidelines for Cd was based on performance data
that represented lower Cd emission levels than the MACT floor,
so using the uncontrolled Cd value as part of the MACT floor
analysis did not significantly impact the final emission
limit. For small plants, it was necessary to use typical
uncontrolled emission values in selecting the MACT floor for
Cd, Pb, Hg, NOx, and dioxins/furans because there were not
enough units with permit limitations to comprise the top
12 percent for these pollutants. As with Cd for large plants,
the EPA is promulgating a MACT level of control more stringent
than the floor for each of these pollutants except NOx;
therefore, the MACT floor and the approach taken to establish
the MACT floor did not significantly impact the pollutant
emission limits in the final guidelines.
Comment: One commenter (IV-D-54) stated that consistency
in applying permit levels is essential. The commenter
reviewed the permit data for the MWC units included in the
data base used by the EPA to establish the floor. Based on
this review, the commenter reported that they identified
discrepancies. As an example, the commenter claimed that the
Barron County MWC unit that the EPA included in its floor data
base for SO2 does not have an SO2 limit in its permit.
Response: Regarding the Barron County MWC, a review of
this plant's section 114 response indicates that a limit of
5.21 lb/hr for SO2 was reported by this plant. This limit was
therefore included in the floor calculation. Since proposal,
the EPA has recalculated the MACT floors for all pollutants
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based on the updated inventory of existing MWC's and the
addition of several operating permits received since proposal
for units which began operation in 1990 or later. The
inventory identified 100 units at existing small MWC plants.
Of these 100 units, 68 were documented as having permits for
at least one pollutant. The number of units comprising the
top 12 percent of the population of small units is 12. The
revised MACT floors for small existing plants are 98 ppm SO2,
560 ppm HC1, 67 mg/dscm PM, 1.1 mg/dscm Cd, 16 mg/dscm Pb,
1.2 mg/dscm Hg, 1,500 ng/dscm dioxins/furans, and uncontrolled
for NOx.
Comment: One commenter (IV-D-90) stated that the EPA's
exclusion from its calculation of the MACT floor and the
guidelines of small MWC plants that did not have permit limits
was unsupportable under the Act. The commenter stated that
the only units that may be excluded from the floor calculation
are those that are demonstrated to achieve LAER within a
specified time period. By excluding the small MWC plants
noted, the commenter contended that the EPA is biased against
existing sources, setting standards that most existing sources
could not meet. The commenter also claimed that federal
enforceability has nothing to do with whether permit limits
may be used to set MACT standards. The commenter said that at
the standard-setting stage, the EPA's obligation is to
characterize the universe of permit limits for a category.
Response: As stated in the proposal preamble
section IV.F.4 (59 FR 48244), the EPA utilized emission
limitations included in Federal and State permits to determine
the MACT floors for units at small existing plants.
Section 129 of the Act states that standards for existing
units "shall not be less stringent than the average emissions
limitation achieved by the best performing 12 percent of units
in the category". Therefore, the EPA considered all units at
small plants known to have emissions limitations (that have
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been achieved) in the population of units for the purpose of
determining the number of units that comprise the top
12 percent. Since proposal, the EPA has reconsidered this
interpretation and has revised the MACT floors such that the
top 12 percent of the entire population of small units was
used.
Prior to proposal, the EPA identified 137 units at
existing small plants, and 88 of these units were determined
to have permit limitations. After proposal, the EPA updated
its MWC inventory of existing plants, identifying 100 units at
existing small MWC plants. The averages of the top 12 percent
of these 100 units (i.e., 12 units) were used to establish the
floor for small plants.
7.4.2 Municipal Waste Combustor Metals (Mercury)
Comment: One commenter (IV-D-98) said that it does not
make sense that the MACT floor emission level for Hg in the
guidelines is more stringent than the MACT floor emission
level for Hg in the NSPS, since the guideline floor is based
on SD/ESP technology and the NSPS floor is based on SD/FF
technology. The commenter said it makes no sense for the EPA
to set the MACT floor for existing plants at 0.36 mg/dscm, or
40-percent reduction, when the EPA admits that Hg removal will
vary from 0 to 50 percent for SD/FF's. The commenter
(IV-D-98) concluded that the Hg floor for the guidelines must
be set at the uncontrolled emission level of 0.65 mg/dscm
which was considered MACT floor for new units at proposal.
Response: The floors for the existing units and the new
units were calculated by different methods, so it is possible
for the floors for existing units to be more stringent than
for new units. As explained in previous responses, the
existing unit floors were based on permit limits, while the
NSPS floors were based on performance of SD/FF controls
without the benefit of carbon injection. Since proposal, the
floor for the NSPS Hg standards was revised to SD/FF/CI based
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on recent data from plants operating with carbon injection,
with a control level of 0.080 mg/dscm. The resulting emission
limitations for new and existing, large and small units remain
the same as proposed (0.080 mg/dscm).
Comment: One commenter (IV-D-55) asserted that the EPA
should subcategorize large plants by technology because the
existing data base confirms, for example, that RDF plants
equipped with SD/FF technology generally can meet the proposed
Hg limit without carbon injection.
Response: If a plant can meet the limits without a
specific technology, the plant is free to do so. As the
commenter stated, RDF plants can generally meet the proposed
Hg emission limit for existing large plants without the use of
carbon injection. The available data indicate that RDF plants
will also be able the meet the proposed dioxin/furan emission
limit without carbon injection. Just because RDF plants can
meet the same emission levels as other MWC's without carbon
injection does not mean there is a need to subcategorize
plants by combustor type.
7.4.3 Nitrogen Oxides
Comment: Five commenters (IV-D-44, IV-D-55, IV-D-56,
IV-D-66, IV-D-85) said the EPA should reconsider the proposed
floor for NOx for existing units at large plants. One
commenter (IV-D-56) said the proposed NOx floor does not
represent a level that can be considered "demonstrated." This
commenter suggested that a NOx level of 235 ppm is a more
appropriate MACT floor. Three commenters (IV-D-44, IV-D-55,
IV-D-85) said that EPA's approach to determining the NOx floor
is flawed because it leads the EPA to conclude that some level
of NOx control is necessary to achieve the floor. Two
commenters (IV-D-44, IV-D-55) claimed that the EPA has already
conceded that the floor for MB/WW combustors could be 230 ppm
and the floor for RDF combustors could be 275 ppm. Two
commenters (IV-D-55, IV-D-98) also asserted that the exemption
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of MB/REF MWC's from meeting the N0X guidelines justifies
further subcategorization of other combustor types.
One commenter (IV-D-55) asserted that because RDF units
emit high uncontrolled levels of N0X, the cost to retrofit
SNCR would not be insignificant, and RDF plants should not be
forced to retrofit with SNCR to meet an artificially low floor
and standard that does not take into account the combustor
type. The commenter provided a table of the N0X permit limits
for 43 RDF units, most of which were derived from EPA's MACT
floor data base, and said the most stringent permit limitation
for RDF units is currently 247 ppmv.
Response: After considering commenter input, the EPA
agrees that N0X emissions vary between combustor types. The
EPA determined that the difference in N0X emissions between
combustor types is significant enough to warrant
subcategorizing the large plant population of existing MWC
units by combustor type in calculating the MACT floor for N0X.
Under this approach, the subcategories and N0X MACT floors are
as follows: 200 ppmv for mass burn waterwall combustors;
250 ppmv for mass burn rotary waterwall combustors; 250 ppmv
for refuse-derived fuel combustors; 240 ppmv for fluidized bed
combustors; no limit (uncontrolled) for mass burn refractory
combustors; and 200 ppmv for other combustors not listed
above.
Comment: One commenter (IV-D-55) contended that,
according to the statute, the EPA must exclude units that
achieved LAER 18 months prior to September 20, 1994. The
commenter argued that the EPA must recalculate the MACT floor
for NOx because there is no evidence in the record (i.e., the
June 30, 1994 memorandum regarding the floor calculation) that
this exclusion was made. Two other commenters (IV-D-55,
IV-D-66) suggested that the MACT floor may be biased by permit
limitations from plants in ozone nonattainment areas that must
meet more stringent requirements.
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Response: At proposal, the MACT floor for N0X was
calculated using the average of the top 12 percent of permit
limitations for existing units located at large plants.
Permits were reviewed and checked against the BACT/LAER
Clearinghouse to determine if SNCR was installed as a result
of a LAER decision within 18 months of proposal or 30 months
of the projected date of promulgation. Any NOx limitations
found to be the result of LAER were not used to calculate the
MACT floor.
7.5 SELECTION OF MAXIMUM ACHIEVABLE CONTROL TECHNOLOGY FOR
MUNICIPAL WASTE COMBUSTOR EMISSIONS
7.5.1 General Comments on Emission Levels
Comment: Several commenters (IV-D-28, IV-D-34, IV-D-41,
IV-D-43, IV-D-44, IV-D-54, IV-D-56, IV-D-59, IV-D-63, IV-D-64,
IV-D-66, IV-D-70, IV-D-80, IV-D-85, IV-D-86, IV-D-92, IV-D-95,
IV-D-96, IV-D-99, IV-D-106, IV-D-114, VI-B-03) expressed
dissatisfaction with the proposed guidelines that are more
stringent than the MACT floor. Several commenters (IV-D-34,
IV-D-43, IV-D-44, IV-D-56, IV-D-66, IV-D-85, IV-D-86, IV-D-95,
IV-D-96, VI-B-03) indicated that in certain cases, the EPA
considers available technology in addition to existing permit
limitations in setting an emission limit more stringent than
the MACT floor, and that the EPA has not adequately presented
the basis and justification for this approach. Six commenters
(IV-D-59, IV-D-63, IV-D-66, IV-D-92, IV-D-96, IV-D-106)
further stated that the proposed standards impose an
unjustified economic burden on local governments and,
ultimately, the public. One commenter (IV-D-44) disagreed
with the EPA's contention that the costs for additional
control more stringent than the floor are minimal. Refer to
section 7.6.2 for further discussion of the economic issue.
Response: The Act directs the Administrator to
promulgate guidelines that reflect the maximum degree of
reduction in emissions of air pollutants, taking cost into
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consideration. Once the MACT floor (i.e., the minimum control
level for evaluation) has been determined, the EPA must
evaluate available technologies to determine MACT (i.e., the
maximum degree of reduction with consideration for cost). The
final guidelines are based on technologies determined to be
MACT.
Standards promulgated for several pollutants (PM, N0X,
and SO2 for small plants; PM, HC1, N0X, Pb, and SO2 for large
plants) are set at the floor levels because it was considered
to be too costly to require control more stringent than the
floor. For the remaining pollutants, standards more stringent
than the floor were determined to be achievable at a
reasonable cost.
Comment: Several commenters (IV-D-28, IV-D-34, IV-D-41,
IV-D-43, IV-D-54, IV-D-63, IV-D-80, IV-D-85, IV-D-92, IV-D-95,
IV-D-96, IV-D-98, IV-D-106, IV-B-03) raised the concern that
the proposed limits would not be achievable. Four commenters
(IV-D-28, IV-D-34, IV-D-41, IV-D-43) contended that the
proposed MACT emission limits are not commercially achievable,
and cannot be guaranteed by the vendor community. Three
commenters (IV-D-43, IV-D-80, IV-D-85) said that in certain
cases the addition of the technology basis is not sound
because it is based on extremely limited pilot test data or
temporary control installations. Five commenters (IV-D-59,
IV-D-63, IV-D-92, IV-D-96, IV-D-106) said the guidelines are
based on limited pilot tests and technology that has
questionable commercial application, and that this is not what
Congress intended. Two commenters (IV-D-54, IV-D-95) said the
proposed guidelines are only theoretically justified, not
demonstrated on actual units in operation.
Response: The technology basis for the final guidelines
is SD/ESP (or FF)/carbon injection/SNCR for large plants and
DSI/ESP/carbon injection for small plants. These technologies
have all been commercially demonstrated on MWC's to support
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the final guideline emission limits. The EPA disagrees with
the commenter's conclusion that the guidelines, as promulgated
are unachievable. Refer to section 7.5.2 for further
discussion of this revision.
Comment: One commenter (IV-D-65) said the EPA's
rationale for "avoiding" standards that would require wet
scrubbers is weak. The commenter maintained that in addition
to better capturing airborne metals, wet scrubbing allows acid
washing to be more easily incorporated into the system. The
commenter said all MWC's should be required to employ wet
scrubbers, FF's, and activated carbon beds, and some should
require SCR. The commenter provided no data.
Response: These are technology-based standards. The EPA
is required to set emission limits based on the performance of
the technology determined to be MACT. MACT was determined to
be SD or DSI with particulate control and carbon injection for
existing plants. As stated in the proposal preamble, wet
scrubbing technology was examined; however, there are little
data from domestic plants using this technology. Any
controls, including activated carbon beds, SCR, or wet
scrubbing, may be used to meet the standards promulgated.
7.5.2 Municipal Waste Combustor Qrcranics
Comment: Several commenters (IV-D-02, IV-D-18, IV-D-28,
IV-D-37, IV-D-38, IV-D-41, IV-D-43, IV-D-44, IV-D-55, IV-D-56,
IV-D-67, IV-D-68, IV-D-82, IV-D-85, IV-D-96, IV-D-98,
IV-D-104, VI-B-02, VI-B-04, VI-B-05, VI-B-06) protested the
MACT standard for dioxin/furans being more stringent than the
floor. Several commenters (IV-D-43, IV-D-44, IV-D-56,
IV-D-68, IV-D-82, IV-D-85, IV-D-104, VI-B-03, VI-B-04)
maintained that the results of limited pilot or experimental
testing for dioxins/furans are not sufficient justification
for establishing more stringent standards. The commenters
said the dioxin/furan standard is not based on emission levels
at a specific plant and, therefore, has not been demonstrated
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to be achievable in practice as required by the Act. Seven
commenters (IV-D-18, IV-D-28, IV-D-85, VI-B-02, VI-B-03,
VI-B-05, VI-B-06) stated that it is inappropriate for the EPA
to base standards on carbon injection results from one test
program instead of on a full-scale commercial operation whose
limits are guaranteed by an equipment supplier. The
commenters urged the EPA to provide further data to support
the assertion that the standard can be achieved in commercial
application.
Two commenters (IV-D-56, IV-D-82) claimed the EPA lacks
the information necessary to assume that the standard is
generally achievable on a continual basis. One commenter
(IV-D-56) said the 50 percent reduction due to carbon
injection is only a theory, not a fact, and using a theory to
set a standard borders on arbitrary and capricious. Four
other commenters (IV-D-28, IV-D-37, IV-D-38, IV-D-44) also
disagreed with the EPA's assumption of 50 percent reduction
for carbon injection. Three commenters (IV-D-18, IV-D-56,
IV-D-85) maintained that the EPA has not demonstrated that
50-percent additional control on a unit equipped with an
SD/FF, SD/ESP, or DSI/ESP will consistently result in
performance below the proposed standards.
Another point of contention raised by the two commenters
(IV-D-18, IV-D-85) was that the Camden MWC testing program may
have achieved its performance due to some factor other than
carbon injection (e.g., higher PM concentrations for baseline
runs than for the test runs). Several commenters (IV-D-18,
IV-D-28, IV-D-85, VI-B-02, VI-B-05, VI-B-06) suggested that
the EPA should collect more operating data from systems now
coming on line with carbon injection before establishing
limits for new and existing facilities.
Two commenters (IV-D-32, IV-D-75) stated that the
proposed dioxin/furan standards are achievable using current
technology with or without carbon injection. One commenter
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(IV-D-32) stated that in many cases the use of a dry scrubber
(spray dryer or dry sorbent injection system) without carbon
injection will be sufficient to meet the standards. This
commenter said one supplier has guaranteed emissions of
30 ng/dscm using a retrofit dry scrubber. One commenter
(IV-D-75) stated that multiple tests since 1987 at the
Commerce MWC (a MB/WW plant) show that the proposed
dioxin/furan guidelines can be met with SD/FF alone and do not
require carbon injection. The commenter interpreted the
proposal to mean that even though the standards were based on
carbon injection, it is not required as long as the standard
is met.
Response: The carbon injection data upon which the
proposed dioxin/furan emission limits were based are from
short-term full-scale MWC tests at commercial MWC's, not
experimental or pilot tests. The Camden MWC test was the
primary test used to assess carbon injection performance prior
to proposal. Data from several MWI's, an HWI, and several
European MWC's were also reviewed. This information is
available in docket No. A-90-45, item number II-B-39. These
multiple tests indicate that a 50-percent supplemental
reduction of dioxin/furan emissions can be achieved with
carbon injection.
After considering commenter input, the EPA agrees with
the commenters that commercial operational data from carbon
injection systems retrofitted to existing MWC's, especially
those equipped with ESP-based control systems, are limited.
Therefore, the EPA has concluded that the MACT level of
control for existing units at small and large plants should be
based on the use of GCP in combination with SD/ESP or SD/FF
for large plants and DSI/ESP for small plants without credit
for carbon injection. Based on available data for these
control systems [previously documented in the preambles to the
promulgated subpart Ca guidelines (56 FR 5514, February 11,
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1991) and proposed subpart Cb guidelines (59 FR 48228,
September 20, 1994)], the EPA concluded that for large plants,
units equipped with SD/ESP can achieve dioxin/furan total mass
emissions of 60 ng/dscm and units equipped with SD/FF systems
can achieve dioxin/furan total mass emissions of 30 ng/dscm.
Similarly for small plants, the EPA determined that units
equipped with DSI/ESP systems can achieve dioxin/furan total
mass emissions of 125 ng/dscm. Therefore, the MACT floor
emission levels of 126 ng/dscm for large plants and
1,500 ng/dscm for small plants can be achieved with SD/ESP or
SD/FF systems in the case of large plants and DSI/ESP systems
in the case of small plants.
When determining the final MACT standard (which may be
more stringent than the MACT floor), section 129(a)(2)
requires the Administrator to consider certain factors,
including the cost of achieving the emission reduction. In
the Administrator's judgement, it would be prohibitively
expensive and unreasonable to require existing MWC's at large
plants with ESP's that can meet a limit of 60 ng/dscm to
retrofit an SD/FF in order to achieve an additional 30 ng/dscm
reduction in emissions more stringent than the MACT floor (see
the proposal preamble, 50 FR 48228, September 20, 1994, for a
more detailed discussion). For the final rule, the
Administrator considered several regulatory options more
stringent than the MACT floor; however, because of this high
pollution control device retrofit cost, the Administrator
decided to get separate MACT limits for MWC's with ESP-based
control systems and MWC's with nonESP-based control systems.
For MWC's with ESP-based APCD systems, the EPA selected a MACT
level of 60 ng/dscm total mass, based on the performance of
SD/ESP systems. For MWC's using or retrofitting nonESP-based
APCD systems, the EPA selected a MACT level of 30 ng/dscm
total mass, based on the performance of SD/FF systems.
Additionally, for small MWC plants, a MACT level of
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125 ng/dscm total mass was selected, based on performance of
DSI/ESP systems.
As discussed in section 7.5.7, the final MACT limit for
Hg is based on the use of activated carbon injection.
Activated carbon injection technology used in combination with
DSI/ESP, SD/ESP, or SD/FF technology is expected to result in
supplemental dioxin/furan control, reducing dioxin/furan
emissions from these control systems by more than 50 percent.
Comment: One commenter (IV-D-55) said the EPA has failed
to take into account that a source is free to demonstrate
compliance with the Hg emission limitation without installing
activated carbon injection. The commenter claimed that such a
source would be at a tremendous disadvantage if it could not
also demonstrate compliance with the proposed dioxin/furan
emission limit. The commenter further asserted that the EPA
should subcategorize large plants by technology because the
existing data base confirms, for example, that RDF plants
equipped with SD/FF technology generally can meet the proposed
Hg limit without carbon injection. The commenter noted that
these plants have already implemented costly APC measures by
installing the more effective FF control and that they should
not be penalized by a dioxin/furan limitation that is overly
stringent because it is based on carbon injection and doesn't
take into account combustor characteristics. One commenter
(IV-D-41) said that another RDF plant, the Nashville MWC, will
not likely achieve the standard.
Response: The final dioxin/furan limits for large plants
have been revised, as discussed in section 7.5.2. The
selected MACT limits are based on APCD as follows: 30 ng/dscm
for units with nonESP-based APCD's and 60 ng/dscm for units
with ESP-based APCD's. These limits were developed based on
units equipped with SD/ESP and SD/FF systems, and not
utilizing carbon injection. Data from RDF plants (8 units)
show that large RDF plants equipped with SD/FF or SD/ESP
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technology can achieve the proposed dioxin/furan emission
limit of 30 ng/dscm without the use of carbon injection. The
RDF dioxin/furan emissions data ranged from 1 to 12 ng/dscm.
Based on these data and the revised dioxin/furan emission
limits, the EPA expects that most RDF units will not be
required to retrofit with carbon injection to meet the final
MWC guidelines.
Comment: Two commenters (IV-D-37, IV-D-38) argued that
the EPA's characterization of uncontrolled dioxin/furan
emissions as 1,000 ng/dscm is incorrect, at least for the
combustor types at the Pinellas and Tampa MWC's. One
commenter (IV-D-38) claimed the Tampa units' rotary design
limits its ability to regulate combustion air, and the limited
boiler surface restricts the plant's ability to reduce ESP
inlet temperatures. These commenters (IV-D-37, IV-D-38) cited
as evidence the recent tests performed at Pinellas and Tampa
in cooperation with the EPA which show much higher emission
levels on a consistent basis, without any clear correlation to
any parameter under control of the operator. Excerpts from
two Pinellas and one Tampa (McKay Bay) test reports are
included.
Response: There are data showing that some combustors
with ESP controls alone could have emissions higher than
1,000 ng/dscm. Data show that secondary formation of
dioxins/furans occurs more rapidly at ESP inlet temperatures
above 440 °F than at lower temperatures. The EPA determined
that 1,000 ng/dscm was a typical value (midpoint). Some
plants will be higher; some plants will be lower. The EPA
expects that large combustors with ESP controls alone will
need to retrofit SD equipment to meet the acid gas levels.
The addition of SD equipment is expected to reduce the ESP
inlet temperatures sufficiently to prevent dioxin/furan
formation in the ESP. With the addition of carbon injection,
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which the EPA expects will be needed for these plants for Hg
control, the dioxin/furan emissions will be further reduced.
7.5.3 Municipal Waste Combustor Metals (other than Mercury)
and Particulate Matter
Comment: Five commenters (IV-D-18, IV-D-28, IV-D-85,
IV-D-98, IV-D-137) stated that the NSPS and emission guideline
emission limits for PM are very tight and will push FF's to
the limits of their control capabilities. Two commenters
(IV-D-18, IV-D-85) indicated that even well-run units may at
times have excursions above the limit. The commenters
(IV-D-18, IV-D-85, IV-D-98) maintained that, compounding the
difficulty in meeting the tight limit, there is a possibility
of interference by activated carbon with particulate control,
particularly on ESP performance. Two commenters (IV-D-18,
IV-D-98) indicated that tighter acid gas control and carbon
injection will result in increased grain loading.
The commenters warned that it is inappropriate to
establish a MACT standard for PM for existing units when data
are not available to prove they can be achieved on a
continuous basis when activated carbon is being injected. One
commenter (IV-D-98) said that although the tests at Camden did
not indicate direct interference from carbon injection,
literature reports that a significant reduction occurred in
ESP PM efficiency following a carbon injection test at an
SD/ESP-equipped plant. The commenter said the EPA should
investigate this issue at the three plants that the EPA said
were going into commercial operation in 1994. Two commenters
(IV-D-18, IV-D-85) recommended that a limit of 0.01 gr/dscf
(21 mg/dscm) can be reliably met, and noted that this would
still be less than two-thirds of the 1991 NSPS limit.
Response: The EPA has considered the commenter's concern
and agrees that use of carbon injection could result in
increased grain loading, resulting in slightly elevated PM
emissions from ESP's. The EPA recognizes that carbon
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injection has not been retrofitted on many existing MWC's.
The EPA made adjustments to account for increased gain loading
from use of carbon injection in selecting the final MACT PM
limits for existing MWC's of 27 mg/dscm for large plants and
70 mg/dscm for small plants.
Comment: Several commenters (IV-D-18, IV-D-28, IV-D-44,
IV-D-56, IV-D-68, IV-D-85, IV-D-98) disagreed with the Cd and
Pb guidelines for large plants and recommended that they be
set at the MACT floor level of control. Four commenters
(IV-D-18, IV-D-28, IV-D-85, IV-D-98) stated that Cd and Pb
emissions should be considered as a percentage of total
particulate, and should be directly linked to the PM
guideline. Three commenters (IV-D-44, IV-D-68, IV-D-85) said
that the proposal of guidelines more stringent than the MACT
floor has not been justified. The commenters stated that the
EPA has argued in the preamble that removal would be
accomplished through the PM control device. The commenters
contended that, although the PM guideline for large plants is
0.012 gr/dscf, the operators will have to continuously achieve
0.002 to 0.005 gr/dscf to meet the Cd guideline. The
commenters (IV-D-18, IV-D-28, IV-D-85) pointed out that for
large plants the Cd guideline (0.04 mg/dscm) is orders of
magnitude below the floor (0.25 mg/dscm), yet the EPA has not
provided data in the docket to prove that MWC's can achieve
the lower guideline through controlling PM to a level of
0.012 gr/dscf. Two commenters (IV-D-18, IV-D-85) acknowledged
that the EPA has presented stack test data showing low Cd
emissions, but claimed this does not explain how such low
emissions can be achieved when the PM guideline is
0.012 gr/dscf. One commenter (IV-D-98) said that the EPA did
not explain how it concluded that 80-percent control of Cd and
98-percent control of Pb are achievable through 99-percent
control of total PM.
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One commenter (IV-D-32) agreed that the proposed PM
emission limits can be met with current ESP and FF technology
for a reasonable cost. The commenter cited data from the
Commerce, Marion County, Spokane, Warren County, Indianapolis,
and Huntington MWC's along with data from the docket as
evidence that the proposed limits are achievable. One
commenter (IV-D-56) agreed with the EPA's reasoning that
high-efficiency PM and metals control can be achieved with
either ESP or FF technology, and applauded the EPA's decision
not to require costly replacement of ESP's with FF's for
marginal pollutant removal gains. The commenter supported
EPA's technical and economic reasoning on this
issue.
Response: The emission limits being promulgated for
large plants are 0.49 mg/dscm for Pb and 0.040 mg/dscm for Cd.
To arrive at the emission limits for Cd and Pb, the EPA
reviewed available MWC emissions test data from MWC's equipped
with SD/ESP's, including data submitted by commenters. The
emission limits were established independently for each
pollutant (PM, Cd, and Pb) at the upper bound (i.e., least
stringent level) of the emissions data, representing a level
achievable by well-operated existing MWC's equipped with
SD/ESP's or SD/FF's. For both Cd and Pb, the permit limits
used at proposal to determine the MACT floor did not reflect
the performance achievable with SD/ESP's and SD/FF's. The
MACT floor for Cd would have required an 80-percent reduction
in the average uncontrolled value, while emissions data
indicated that over 98-percent reduction was achievable with
SD/ESP's and SD/FF's. The MACT floor for Pb would have
required a 98-percent reduction in the uncontrolled value,
while emissions data indicated that over 99-percent reduction
was achievable with SD/ESP's or SD/FF's. After proposal,
additional permits were received and the floors were revised
as described in section 7.4.1. The revised floor for Pb is
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0.49 mg/dscm and for Cd is 0.097 mg/dscm. Because the revised
floor for Pb is now lower than the proposed guideline of
0.50 mg/dscm, the guideline is being promulgated at the floor
level of 0.49 mg/dscm. Although the revised floor for Cd is
more stringent, it does not reflect the higher level of
control achievable by SD/ESP-equipped units as demonstrated by
available emissions data (see items II-B-34 and II-A-45 in
docket A-90-45). Therefore, the EPA is selecting MACT for Cd
at the proposed level of 0.040 mg/dscm.
7.5.4 Municipal Waste Combustor Acid Gases
Comment: One commenter (IV-D-32) agreed that the
proposed HC1 and SO2 guidelines can be met easily. The
commenter also claimed that the required removal percentages
for small plants could be increased to 70 percent for SO2 and
85 percent for HC1, without making scrubber costs exorbitant.
One commenter (IV-D-56) supported the SO2 and HC1 standards as
long as there remains a percent removal efficiency option as
proposed.
Response: The EPA acknowledges these commenters' support
for the proposed guidelines. However, the EPA does not
believe that DSI/ESP systems, the basis for the emission
guidelines for small MWC's, can continuously achieve reduction
efficiencies as high as suggested by the commenter. The EPA
determined that a 50-percent reduction was achievable. The
50-percent removal efficiency option will remain as proposed.
Comment: Four commenters (IV-D-54, IV-D-64, IV-D-80,
IV-D-120) contended that the SO2 emission limit for small MWC
plants is unreasonable. Three of these commenters (IV-D-54,
IV-D-64, IV-D-80) recommended that the SO2 limit be set at the
MACT floor level. The commenters indicated that the EPA
assumed that plants would require emission controls such as
DSI/FF's in order to reduce SO2 emissions from an uncontrolled
value of 160 ppm to the floor of 120 ppm. The commenters
pointed out that, based on this assumption, the EPA concluded
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that since small plants already required acid gas control to
meet the floor, they could just as easily meet a limit of
80 ppm without significant cost. The commenters said the
analysis is in error because it is based on an incorrect
uncontrolled value.
One commenter (IV-D-80) said CEM data at the Olmstead MWC
indicate that 120 ppm is a more accurate estimate of
uncontrolled data. The commenters (IV-D-54, IV-D-64) said
data from Minnesota and Wisconsin indicate that small plants
have an uncontrolled level of less that 120 ppm and would
require no control to meet the floor. The commenter said that
since many small MWC plants can meet the floor without
controls, the cost impact of achieving a more stringent
control level of 80 ppm would be significant and must be taken
into account.
Response: The EPA has considered the commenters'
concerns regarding whether small plants actually require acid
gas control to achieve the floor. Assuming the commenters'
assertions that 120 ppm is a more reasonable value for
uncontrolled emissions are correct, the EPA would not conclude
that acid gas is required to meet the proposed floor of
118 ppm. However, data submitted by the commenters to support
their assertion that 120 ppm is a more representative level of
uncontrolled SO2 emissions indicate that 120 ppm is not
continuously achieved on a 24-hour basis over a period of
several months. The data indicate that 120 ppm is frequently
achieved for shorter time periods. In addition, the MACT
floors were revised after proposal as described in
section 7.4.1, and the revised SO2 floor for small plants was
determined to be 98 ppmv. The EPA believes acid gas controls
will be needed by these plants to achieve the revised floor,
and there will be little additional cost to achieve a level
somewhat lower than the floor. As at proposal, the final SO2
emission limit selected as MACT is 80 ppmv on a 24-hour basis.
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The 50-percent removal efficiency option will also remain in
the final rule as proposed.
7.5.5 Nitrogen Oxides
Comment: One commenter (IV-D-05) requested clarification
of the definition of "mass burn/refractory" units which fall
under the exemption from additional N0X control. The
commenter stated that the facility in question has "a
multi-pass mass burn waterwall system with refractory in the
furnace and first pass of the boiler", and has uncontrolled
emissions of 203 ppm which are below the proposed MACT floor
and would be exempt if the definition does not exclude
waterwall systems that employ refractory.
Response: Mass burn/refractory MWC's are defined as
having no heat recovery (i.e., no waterwalls) in the furnace
(i.e., radiant heat transfer section). However, heat recovery
may occur in a convective pass waste heat boiler. Based on
the commenter's description, the commenter's MWC is a mass
burn/waterwall unit and would be subject to the NOx emission
limit promulgated for mass burn waterwall units at large
plants. Since proposal, the NOx emission limits were revised
based on subcategorization by combustor type and the mass burn
waterwall limit is 200 ppmv. See another comment in this
section for further discussion of the final NOx emission
limits.
Comment: One commenter (IV-D-24) declared that the EPA
ignored beneficial impacts of the following combustion
design/operating strategies and add-on controls and said these
should be given consideration for NOx control for both large
and small plants: grate/furnace design for staging
combustion; waterwall cooling of the grate area; automatic
combustion controls; bubbling and circulating fluidized bed
boilers; overall design to permit flue gas recirculation;
NOxOUT; KRC Two-Stage DeNOx Process; SCR; and wet scrubbing.
The commenter claimed that a combination of one or more of
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these can achieve 100 ppm and cited the following paper to
support this argument: "Technologies for Minimizing the
Emission of NOx from MSW Incineration", published in the
Proceedings of the International Conference on Municipal Waste
Combustion, April 11-14, 1989. A second commenter (IV-D-74)
suggested that the EPA analyze the use of the flue gas
recirculation in further reducing NOx emissions, particularly
for small plants since the proposal allows small plants to
remain uncontrolled.
Response: An individual owner or operator of an MWC is
free to select any approach or technology that can meet the
limits. Although the EPA recognizes the merit of the
technologies/techniques noted by the commenters, SNCR is the
best technology demonstrated in the United States as
applicable to designated MWC's. The EPA has some reservations
regarding the use of SNCR on modular units and mass
burn/refractory units, as discussed in the proposal preamble.
Other control technologies have been examined (refer to
document Nos. EPA-600/R-94-208 and EPA-450/3-89-27d); however,
the percent reductions attainable with many of these
technologies are low and data are limited. As stated above,
an individual owner or operator of an MWC is free to select
any approach or technology that can meet the promulgated
limits.
Comment: Several commenters (IV-D-28, IV-D-37, IV-D-38,
IV-D-41, IV-D-44, IV-D-54, IV-D-55, IV-D-56, IV-D-66, IV-D-67,
IV-D-69, IV-D-82, IV-D-85, IV-D-86, IV-D-87, IV-D-88, IV-D-98,
IV-D-136, VI-B-02, VI-B-03, VI-B-04, VI-B-05, VI-B-06) said
that the proposed emission guideline of 180 ppm for large
existing MWC's is too stringent and should be revised. The
commenters raised various points in support of the arguments,
as follows.
Some of the commenters (IV-D-28, IV-D-37, IV-D-38,
IV-D-41, IV-D-54, IV-D-55, IV-D-85, VI-B-02, VI-B-03, VI-B-04,
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VI-B-05, VI-B-06) said that while the 180 ppm level may
theoretically be achievable for newer units designed with
SNCR, such as Stanislaus, it is not achievable or commercially
demonstrated for existing MWC's whose boilers were typically
designed ten or more years ago. Several commenters (IV-D-28,
IV-D-41, IV-D-54, IV-D-82, IV-D-85, IV-D-87, VI-B-02, VI-B-05,
VI-B-06) contended that the EPA, relying solely on data
generated at one MWC (Stanislaus), has not exhibited in the
docket a sufficient data base with long-term CEM data showing
that 180 ppm can be achieved by retrofitted MWC's. Several
commenters (IV-D-37, IV-D-38, IV-D-44, IV-D-66, IV-D-85,
IV-D-86) claimed no MWC's have been retrofitted for NOx
controls and, therefore, SNCR is not demonstrated in this
application. These commenters questioned whether the
injectors can be properly located and whether existing plants
are capable of maintaining the required temperature window in
a predictable location. One commenter (IV-D-44) said that
test results from one plant, Stanislaus, are not
representative of the best performing 12 percent of units and
cannot be expected to apply to all retrofit situations.
Several commenters (IV-D-28, IV-D-41, VI-B-02, VI-B-03,
VI-B-05, VI-B-06) indicated that the vendors will not
guarantee 180 ppm. Two commenters (IV-D-28, IV-D-85) stated
that the standard should be revised to 235 ppmv (dry) at
7 percent O2 based on a 24-hour average. One commenter
(IV-D-85) said 235 ppm would represent a 33-percent reduction
for some of the old units, which the EPA's data have shown can
emit NOx to levels as high as 350 ppm.
Four commenters (IV-D-37, IV-D-38, IV-D-85, IV-D-98)
recommended that the NOx limit be set at the floor, after
recalculating the floor with additional subcategorization by
combustor type. Two commenters (IV-D-55, IV-D-136) contended
that there are no data to suggest that an RDF plant
retrofitted with SNCR could attain 180 ppmv. One commenter
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(IV-D-139) said that SNCR can be retrofitted successfully on
RDF units and there is at least one RDF facility with a
retrofit with 132 ppm guaranteed.
One commenter (IV-D-87) noted that the Mid-Connecticut
MWC, which was studied by the EPA in 1989, would be able to
meet the MACT floor of 215 ppm with no additional controls.
Response: Fourteen MWC's in the U.S., including five
plants that have recently come online, have applied SNCR.
Additionally, this technology has been applied to MWC's
overseas. The EPA believes this technology can be
successfully retrofitted on existing MWC's. According to
vendors of this technology, existing plants, including RDF
units, have an advantage over new plants in that the
temperature profiles are already known, which will allow
optimization of the system to be completed in a short amount
of time. As discussed in the proposal preamble, the EPA has
reservations regarding retrofit of SNCR to existing mass
burn/refractory units (described in 40 CFR 60 IV.F.2.c) and,
therefore, NOx control is not required for this type of MWC.
The EPA also discussed reservations regarding retrofit to
modular units, and is not promulgating a NOx limit for small
MWC's.
After considering the commenters' concerns about the
difference in performance between combustor types, the EPA
revised the MACT floors for NOx by subcategorizing the
existing large MWC plant population by combustor type. The
EPA has determined MACT to be at the MACT floor levels for
each combustor type because it would not be cost effective to
require control beyond the MACT floor. Refer to section 7.4.1
for more description of the MACT floor revisions. The MACT
limits being promulgated for NOx at large plants are as
follows: 200 ppmv for mass burn waterwall combustors;
250 ppmv for mass burn rotary waterwall combustors; 250 ppmv
for refuse-derived fuel combustors; 240 ppmv for fluidized bed
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combustors; no limit for mass burn refractory combustors; and
200 ppmv for other combustors not listed above.
Comment: Two commenters (IV-D-28, IV-D-87) requested
that the EPA allow MWC's the flexibility to use ERC's to meet
the NOx emissions standards in States where ERC's are part of
the State regulations and SIP's. The commenters pointed out
that the EPA already allows plants to use ERC's to meet SO2
limits, and that the trading program appears to be working
well. One commenter (ID-D-87) warned that compliance without
ERC's will create a "regulatory nightmare" with a nearly
impossible compliance schedule for plants in non-attainment
States such as Connecticut. The commenter (IV-D-87) said that
by May 31, 1995, these States will have to meet Phase I NOx
emission limits; next, these States will have to meet the
proposed MWC emission guidelines; then, by May 31, 1999, these
States will have to meet Phase II NOx emission limits; and
finally, if attainment is not achieved in Phase II, there will
be a Phase III default plan. The commenter (IV-D-87) said
these schedules mean that plants will either have to change
their control systems three times to meet the changing
emission limits, or "will have to buy the third system first
(if such systems are now available) in order to achieve
compliance at the later dates." The commenter (IV-D-87)
stated that without the availability of an ERC program for NOx
credits, the plants are doomed to waste massive amounts of
money or risk non-compliance.
Both commenters (IV-D-28, IV-D-87) strongly asserted that
it would be discriminatory and scientifically insupportable
for the EPA to deny a specific type of plant, such as MWC's,
the right to use ERC's, while allowing other sources to
utilize the "credit market."
One commenter (VI-B-03) expressed serious reservations
about the ultimate level of NOx control that plants such as
the Alexandria/Arlington MWC may face. The commenter
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explained that this MWC is in an ozone nonattainment area, and
that, according to EPA's Oxidant Modeling project, the entire
Northeast corridor may require a 70-percent reduction in N0X
to achieve compliance with the NAAQS for ozone.
Response: The EPA acknowledges the commenters' concerns
and has added a provision to the emission guidelines under
which States may choose to allow emissions averaging of N0X
emissions between units at an MWC plant and emissions trading
of N0X emissions between plants as part of their State plans,
if they so desire.
Emissions averaging allows plants flexibility in the
level of control applied to each individual MWC unit, as long
as greater plant-wide N0X reduction is achieved than if every
individual unit had met the limit. This may allow some plants
to control only some of their units and achieve the required
emission reduction at less cost. The combination of units
included in an emissions averaging plan at an MWC plant must
meet emission limits approximately 10 percent more stringent
than the single unit emission requirements. The emission
limits under the emissions averaging plan are: 180 ppmv for
mass burn waterwall combustors; 220 ppmv for mass burn rotary
waterwall combustors; 230 ppmv for refuse-derived fuel
combustors; 220 ppmv for fluidized bed combustors; no limit
for mass burn refractory combustors; and 180 ppmv for other
combustors not listed above. The average emissions must be
determined on a 24-hour daily basis.
If a unit included in the emissions averaging plan is
offline on a particular day, resulting in difficulty for the
plant in meeting its daily emissions averaging limit, the
owner or operator of the plant may opt to determine compliance
for that day by an alternative method. The owner or operator
must demonstrate that each of the units included in the
emissions averaging plan and online that day is operating at
or below the maximum daily 24-hour average emission level
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measured for that unit from all days during which the
emissions averaging plan was achieved with all units online
during the last calendar quarter. If this alternative method
of compliance is chosen, the owner or operator must also
demonstrate that the average kilograms per day of N0X emitted
over the days using the alternate method is less than the
average kilograms per day emitted over the days the emissions
averaging plan was achieved with all units online. These
average kilograms per day values are to be determined on a
calendar year basis. The annual provisions ensure that on an
annual basis the emissions average (considering shutdowns)
achieves as much reduction as if the emissions average had
been met on a daily basis throughout the year.
For plants that participate in N0X trading programs,
these programs must be consistent with the Open Market Trading
Rules for Ozone Smog Precursors (proposed on August 3, 1995 at
60 FR 39668) as finally promulgated. Until the Open Market
trading rule is finalized, it is not possible to reference the
rule in the guidelines text. In the interim, the guidelines
text indicates NOx emissions trading must be approved by the
Administrator prior to implementation. After the Open Market
Trading Rule is finalized, it is preapproved for use under the
guidelines. These options are designed to allow owners or
operators flexibility while at the same time ensuring that the
amount of NOx emitted into the air is controlled.
7.5.6 Good Combustion Practices
Comment: Two commenters (IV-D-71, IV-D-72) were
concerned that there are no startup, shutdown, or upset
provisions in the CO guideline. One commenter (IV-D-71)
recommended a revision of the CO limit for modular starved-air
units to 250 ppmv, 24-hour average, during startup and
shutdown. The commenter agrees that the 50 ppm, 4-hour
average, guideline is achievable during normal operations;
however, the normal stoichiometric balance is upset during
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periods of startup, shutdown, or emergencies, resulting in CO
spikes that auxiliary burners have limited ability to correct.
One commenter (IV-D-72) said that while the proposed 100 ppm,
4-hour average, guideline for FBC's is reasonable under
steady-state conditions, it is impossible to meet under
startup, shutdown, or upset conditions. Neither commenter
provided specific data in support.
Response: The regulations specify that a 3-hour period
is allowed for startup, shutdown, and malfunctions during
which the standards do not apply. If a longer period is
needed, however, compliance with CO emission limits during
startup and shutdown can be achieved by the use of an
auxiliary fuel. The startup of a unit begins when operators
begin feeding waste to the unit. Shutdown ends when all waste
and ash has been cleared from a combustor's grates/furnace.
By appropriate use of an auxiliary fuel such as natural gas, a
unit can use the following or a similar sequence of operation
to avoid a violation of the CO emission limit during startup:
1. Begin heating up the unit with auxiliary fuel (it is
the responsibility of the operator to establish the
time and temperature to which the unit is to be
heated before waste is introduced to the unit).
2. Begin feeding of waste to the unit and continue to
fire auxiliary fuel.
3. Continue to fire auxiliary fuel as the unit is
brought up to full operating load. Reduce the
amount of auxiliary fuel firing as needed to comply
with the load limitation by firing at a sufficient
rate to maintain adequate furnace temperatures and
low CO emission concentrations.
4. When waste combustion conditions reach steady-state
conditions where adequate furnace temperatures and
steam flow rates can be maintained by waste
combustion alone, the firing of auxiliary fuel may
be terminated.
A similar sequence could be used during shutdown:
1. Begin firing auxiliary fuel when feeding of waste to
the unit is terminated.
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2. Continue to burn auxiliary fuel in the unit until
all waste has been cleared from the grates/furnace.
The rate at which auxiliary fuel is fired must be
sufficient to maintain high furnace temperatures
which promote complete furnace destruction of
organics and maintain low CO emission
concentrations. The burning of auxiliary fuel may
be terminated when all waste has been cleared from
the grates/furnace. The requirement for complying
with the Federal CO emission limit for MWC's ends
when the firing of MSW ends.
Comment: Two commenters (IV-D-25, IV-D-38) strongly
requested that the CO limit for rotary refractory combustors
be specified as 250 ppm corrected to 7 percent O2 based on a
24-hour average. The current proposal is 100 ppm based on a
24-hour average.
The first commenter (IV-D-25) pointed out that, while the
1991 guidelines specifically exclude rotary combustors without
waterwalls from both the mass burn rotary waterwall class and
the mass burn refractory class, the current proposal does not
address unit classification and a clarification is needed.
One commenter (IV-D-25) submitted an attachment
describing data and rationale previously submitted in support
of such a limit. The commenter stated that these issues were
reviewed in a March 22, 1994, EPA memorandum from
James Kilgroe to Walt Stevenson, and that Mr. Kilgroe did not
agree that rotary waterwall combustors and rotary refractory
combustors should be subject to the same limit. The other
commenter (IV-D-38) also referred to the previous
correspondence. Both commenters questioned the basis of the
decision. One commenter (IV-D-38) claimed that without this
reclassification, Tampa will be forced to close or to install
an entirely new combustor in addition to the expected APCD
retrofits.
One commenter (IV-D-25) stated that the primary data
appeared to be from tests at the Dayton South MWC and the
McKay Bay MWC. This commenter indicated that although some of
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the Dayton South data were below 100 ppm without lime
injection, other data were 150 to 400 ppm when lime injection
was being used. This commenter questioned whether the McKay
Bay data were corrected for O2, and criticized the use of some
of the data that were obtained through an Orsat analysis
(Method 3) instead of a performance test.
This commenter (IV-D-25) also asserted that CEM data
instead of stack tests should be considered in setting the CO
limit, as was done for other types of combustors such as
rotary waterwall and RDF units. This commenter provided CEM
data from Units 1 and 2 at Dayton North, which both use
limestone injection for SO2 control by permit condition.
Both commenters (IV-D-25, IV-D-38) asserted that the
technology of the rotary refractory combustors is sufficiently
similar to the rotary waterwall combustors to justify similar
treatment under the emission guidelines.
One commenter (IV-D-25) cited "Good Combustion Practices
of MWC Facilities: CO Emission Limit Requirement," prepared
by Agrawal and von Alten, Energy and Environmental Research
Corporation, for the EPA, November 1990, and provided a
discussion of the similarities in the combustors. This
commenter contended that EPA's proposed modifications, which
are already starting to be implemented at the Montgomery
plants, address the major differences between the
technologies. This commenter cited the August 1989 BID as
saying that the proposed modifications would reduce CO levels
to 150 ppmv for Volund units, and stated that with normal
fluctuations and without the proposed modifications, an
emission limit of 250 ppm is justified.
One commenter (IV-D-38) provided a detailed discussion
supporting the change, and included as a attachment a letter
with arguments specifically responding to Mr. Kilgroe's
March 22, 1994 letter.
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Response: The Montgomery County Solid Waste Management
Department submitted comments to the EPA on the proposed
regulations for existing MWC's. They indicated that EPA had
failed to set separate emission limits for rotary refractory
combustors. They claimed that the rotary refractory units are
similar to rotary waterwall combustors and requested that the
CO emission limits for rotary refractory mass burn combustors
be set at 250 ppm at 7 percent O2 on a 24-hour average.
Similar comments were submitted on behalf of the rotary
refractory combustor facility in Tampa, Florida (McKay Bay).
The CO emission limits for mass burn refractory
combustors which were proposed in 1989 and promulgated in 1991
were intended to cover all types of mass burn refractory
combustors including rotary refractory combustors. The CO
emission limits for both new and existing mass burn refractory
units were 100 ppm at 7 percent O2 on a 4-hour average. The
results of EPA tests on Unit 3 at the Montgomery South Plant
were considered when establishing the CO initial emission
limits for mass burn combustors.
In early 1994, the owners of the McKay Bay and Montgomery
County MWC's petitioned the EPA to set separate CO emission
limits for mass burn rotary refractory combustors. They cited
the separate emission limits for waterwall refractory units
and contended that similar separate emission limits should be
established for mass burn rotary refractory units. The EPA
responded by establishing CO emission limits of 100 ppm on a
24-hour averaging time for existing mass burn rotary
refractory combustors. These same emission limits were
proposed in the September 20, 1994 rules for MWC's.
Rotary refractory combustors of the Volund type are
considered by EPA to be a different type of combustor than the
Westinghouse O'Connor rotary waterwall combustor. The Volund
is basically a refractory combustor while the Westinghouse
combustor is a waterwall combustor. Primary and secondary air
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is added through the rotating waterwalls of the Westinghouse
combustor. Tertiary combustion air is also added into a
secondary waterwall combustion chamber above the rotary kiln
exit.
The Volund style combustors contain a primary refractory
combustion chamber called an ignition chamber, followed by a
rotary refractory kiln, an ash pit, and a mixing chamber.
Combustion gases from the ignition chamber enter a refractory-
lined bypass duct at the top of the ignition chamber where
they flow over the top of the kiln and into the mixing chamber
over the ash pit. Combustion air is provided to the Volund
type units as under and overfire air in the ignition chamber.
The Volund style unit at the Montgomery County North and
South Facilities are of an earlier generation of designs than
the Tampa Facility. The Tampa units contained zoned underfire
air and the Montgomery County units do not. Neither the
Montgomery County nor the Tampa Facilities contain modern
computer operated distributed combustion control systems.
The refractory kiln Volund style units and waterwall kiln
Westinghouse style units are sufficiently different in design
and operation to warrant separate CO emission limits.
The Montgomery County Department of Solid Waste
Management provided CO emission data from the Montgomery
County North and South Plants to support their request for a
higher emission limit for mass burn rotary refractory MWC's.
Data were provided on a hourly and 24-hour basis. Most of the
data were from Unit 1 and Unit 2 of the North Plant. As
expected, the averages and variability of the 24-hour data
were much lower than for the hourly averages. Data on 24-hour
averages on Unit 1 and Unit 2 of the North Plant were
presented for January 12, 1992 through January 31, 1993.
No information on operating conditions [temperatures, O2
concentrations, waste feed rates, or waste conditions (dry,
normal, or wet)] was provided with the CO emission data.
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Also, no data were available for significant periods of time,
especially for Unit 2. For 4 months, when similar amounts of
data were available for both units (January 1992 though April
1992), average CO emissions from Unit 2 were approximately 2
to 3 times higher than CO emissions from Unit 1. No
information was provided on design or operating conditions
which may have caused this difference.
Although not noted by Montgomery County, there appeared
to be a seasonal effect on CO emissions. The lowest average
CO emissions were recorded for Unit 1 during March and early
April when 16 of the 30 days of available data exhibited
average CO emissions of less than 100 ppm. The highest CO
emissions occurred during the months of July, August, and
September. During one 4 day period in July, average daily CO
emissions from Unit 1 ranged from 952 to 1,357 ppm. It is
possible that seasonal and monthly periods of high CO
emissions corresponded to periods when large amounts of yard
wastes or wet wastes (rain or snow) were being burned.
It is probable that the high CO emissions at the
Montgomery County Plants were the result of the design and
operating features of the combustors. The major design
deficiencies include poor provisions for the distribution of
combustion air and the lack of modern computer operated
combustion control systems. Operating conditions which
probably contributed to high CO emissions were a lack of
operating training, lack of a requirement for low CO
emissions, and the injection of limestone into the ignition
chamber for SO2 control.
During EPA testing at Montgomery County and other
facilities it has been found the CO emissions are highly
dependent on the skills of the operator, and the attention
paid to maintaining good combustion conditions. This is
especially true of MWC's which do not have distributed
combustion control systems, but have manually operated
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controls such as those used at the Montgomery County North and
South plants.
During the EPA sponsored tests on Unit 3 of the
Montgomery County South plant, the plant operators were
instructed to maintain good combustion conditions by
maintaining adequate O2 concentrations in the combustor, and
temperatures of approximately 980 °C (1,800 °F) and 925 °C
(1,700 °F), respectively in the ignition and mixing chambers.
During six tests with good combustion conditions, CO
concentrations in the stack ranged from 16.5 to 51.6 ppm.
During three tests with poor combustion conditions with the
ignition chamber operated at a temperature of 1,040 °C
(1,900 °F) and the mixing chamber at 800 °C (1,475 °F),
average stack concentrations of CO ranged from 118 to 412 ppm.
When limestone was injected into the ignition chamber at
500 lb/hr through the overfire air port in the side of the
ignition chamber, average CO emissions increased to 108 to
303 ppm even though the combustion temperature was maintained
at the good combustion levels. When limestone (CaC03) is
injected into the high temperature region in the injection
chamber it decomposes via an endothermic reaction to form lime
(CaO) and CO2• The higher levels of CO during the injection
of limestone probably result from the quenching of combustion
reactions by the endothermic limestone decomposition
reactions, or by the dissociation of CO2 into CO and O2•
When wet wastes are combusted it is often necessary to
modify operation of the combustor to control CO emissions.
Corrective actions include the use of preheated air, a
reduction in waste firing rates, and changes in the combustion
air distribution. These changes in operation are used in
state-of-the-art MWC's that employ GCP.
It is EPA's understanding that the Montgomery County
Facilities continue to inject limestone into the furnace, a
factor which contributes to elevated CO emissions. The
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Montgomery County Department of Solid Waste Management
Department has not provided documentation that they have taken
corrective actions to control CO emissions and it is assumed
that the emission data submitted to the EPA do not represent
good operating practices.
To comply with the proposed emission guidelines (and an
Ohio Consent Decree) the Montgomery County MWC's must install
spray dryers, employ GCP, and implement operator training
procedures intended to insure good operating practices. Based
on available evidence from the EPA's field test program at
Montgomery County and a knowledge of combustion practices in
MWC's, it is concluded that existing mass burn rotary kiln
combustors can achieve CO emission limits of 100 ppm on a
24-hour average.
Comment: Several commenters (IV-D-18, IV-D-28, IV-D-29,
IV-D-30, IV-D-43, IV-D-44, IV-D-51, IV-D-73, IV-D-74, IV-D-85,
IV-D-98, IV-D-103) agreed that operator certification and
training are appropriate requirements, but disagreed with the
timing, saying that the 6-month period is not adequate to
fully train and schedule testing and certification. Five
commenters (IV-D-51, IV-D-73, IV-D-74, IV-D-85, IV-D-103)
pointed out that certification could be required before the
end of 1995. The five commenters suggested that training and
testing sites in numerous locations in every State will be
required in order to offer all personnel sufficient
opportunity to obtain training and certification. Given the
number of operators that will now require training nationwide,
the commenters (IV-D-28, IV-D-29, IV-D-30, IV-D-43, IV-D-85)
urged the EPA to begin discussions with ASME to fully develop
the training program, and indicated that a phase-in period may
be needed. One commenter (IV-D-28) said the EPA should
consider whether other training organizations should also be
allowed to provide training for operation.
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One commenter (IV-D-29) informed the EPA that applicants
are required to document 6 months of satisfactory employment
in the capacity of chief facility operator or shift supervisor
as a prerequisite for full ASME operator certification. This
commenter said the proposed rule is not clear whether an
operator would be permitted to work as a chief facility
operator or shift supervisor during the period prior to
becoming eligible for full certification. This commenter also
pointed out that the site specific examination is conducted by
a three-member ASME board of examiners, including one
technical representative from the resource recovery industry
and one representative from the regulatory authority. The
commenter indicated that lead times of 6 months are often
necessary for the scheduling of exams.
Two commenters (IV-D-43, IV-D-44) suggested that a 2-year
period for certification is more reasonable given the current
state of the ASME certification program. One commenter
(IV-D-85) said that 3 years is more appropriate, and an
extension provision should be provided if delays result from
the hazards of developing a new certification process.
Response: The EPA has discussed the issue of
certification with ASME and agrees that the proposed schedule
is unrealistic given the limited resources for testing all
those who require full certification. Because provisional
certification is required by ASME as the first step in
attaining full certification, time is being allowed for both
the provisional and full certification requirements to be met.
Most of the large plants have already been provisionally
certified in accordance with the 1991 MWC rule. The proposed
regulations are revised such that all chief facility operators
and shift supervisors at large plants have 1 year from
promulgation or 6 months from startup to become provisionally
certified by ASME (or State-approved equivalent). In
addition, within 1 year after promulgation or 6 months after
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startup, all chief facility operators and shift supervisors at
large plants must complete or become registered for the ASME
(or State-approved equivalent) full certification exam. For
small plants, the proposed regulations are revised such that
all chief facility operators and shift supervisors have
18 months from promulgation or 6 months from startup to become
provisionally certified by ASME (or State-approved
equivalent). In addition, within the first 18 months after
promulgation or 6 months after startup, all chief facility
operators and shift supervisors at small plants must complete
or become registered for the ASME (or State-approved
equivalent) full certification exam. These changes will
ensure that all operators are, at a minimum, provisionally
certified and are scheduled to be fully certified as soon as
can be accommodated by ASME (or State-approved equivalent).
7.5.7 Municipal Waste Combustor Metals (Mercury)
Comment: Several commenters (IV-D-37, IV-D-44, IV-D-55,
IV-D-56, VI-B-03, VI-B-04) asserted that the Hg emission limit
should be revised due to lack of demonstrated data. One
commenter (IV-D-18) maintained that commercial application of
technology often isolates problems not observed during
short-term test runs. One commenter (IV-D-56) urged the EPA
to revise the guideline to 0.10 mg/dscm or 80-percent removal,
whichever is less stringent. While it was acknowledged that
carbon injection is efficacious and can be used to meet a
standard more stringent than the floor, the commenter said the
proposed guideline is not technically justified. The
commenter provided no data or other discussion in support of
the suggested change.
One commenter (IV-D-55) suggested a limitation of
0.15 mg/dscm with and alternate percent reduction of
75 percent for existing plants because MWC plants on a
nationwide basis have not demonstrated an ability to meet the
proposed Hg emission limitation continuously. The commenter
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conceded that fourteen data points taken at the Stanislaus MWC
show the limit is capable of being achieved; however, those
data were collected during a high carbon feet rate of 0.72 lb
carbon/ton MSW and the commenter claimed that the EPA has
ignored data indicating that the proposed limit may not be
easily achieved at a slightly lower carbon feed rate. In
support, the commenter provided a table of Hg removal rates
versus carbon injection rates during multiple tests at four
plants (Burnaby; Zurich, Switzerland; Stanislaus; and Camden).
Referring to these data, the commenter pointed out that the
Burnaby plant, at an injection rate of 0.55 lb carbon/ton MSW,
achieved only 53-percent reduction. The commenter stated that
the average outlet Hg concentration and average removal rate
for the 0.36 lb carbon/ton MSW correspond to the proposed
emission guidelines but allow no margin between the emission
limitation and the achieved emission level.
Three commenters (IV-D-37, IV-D-44, VI-B-04) stated that
pilot or demonstration projects are not an appropriate basis
on which to set the emission guidelines, and performance based
on these projects cannot be broadly expected to apply to all
retrofit situations. Two commenters (IV-D-37, IV-D-44) said
"the results are not representative of the permit limitations
of the best performing 12 percent of all units". These
commenters recommended that the limit be set at the floor
level.
Two commenters (IV-D-32, IV-D-108) agreed that the
proposed Hg limits are achievable using current technology,
including carbon injection. One commenter (IV-D-32) cited one
report showing 99-percent Hg control efficiency by an SD/FF
alone, and another showing greater than 98-percent reduction
to a level below 0.050 mg/dscm using carbon injection with an
SD/FF. The commenter cited yet another paper which presented
results of 0.070 mg/dscm using Sorbalit technology as an
alternative to carbon injection. One commenter (IV-D-108)
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noted that the 85-percent reduction standard based on the
Stanislaus and Camden County tests is reasonable since more
recent data show actual efficiencies to be well above
95 percent.
Response: Activated carbon injection has been used
commercially on MWC's in Europe and Canada, where the
performance capabilities of this control technology have been
demonstrated. It is not possible to directly translate data
gathered in Europe and Canada due to differences in test
methods and other procedures. For these reasons, the EPA
conducted testing at two U.S. MWC's (Stanislaus County and
Camden County) to assess the capabilities of this control
technology. Also, 5 U.S. MWC's that began using activated
carbon injection technology since 1994 (Union County, Lee
County, Onondaga County, Falls/Bucks County, and Hennepin
County MWC's) are meeting the proposed limits. In addition,
the Alexandria/Arlington MWC, equipped with flue sorbent
injection and ESP's, was retrofitted in 1993 with carbon
injection for mercury control, and data indicate that the
proposed limits are being achieved.
Regarding the commenter's discussion of the Stanislaus
data, the EPA's initial analysis of the data showed that
80-percent reduction was achievable. However, subsequent
analyses based on the combined knowledge gained from the
Stanislaus County, Camden County, and other tests concluded
that higher Hg reductions could be continuously achieved by
increasing the carbon feed rate. This analysis concluded that
at a carbon injection rate of approximately 100 mg/dscm
(0.8 lb carbon/ton MSW) the proposed limit of 80 mg/dscm or
85 percent reduction would be achieved. This analysis also
examined the impact of further increasing carbon feed rates to
achieve even lower Hg emissions and the impact of variability
in the Hg content of MSW. The EPA did an economic analysis
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(refer to docket No. A-90-45, item number II-A-13) and
determined the costs of carbon injection to be reasonable.
Based on the testing done by the EPA, activated carbon
injection can be retrofitted to existing plants. The MACT
floors for existing plants represent Hg emission levels higher
than levels that can be achieved using carbon injection. The
EPA has selected MACT for Hg at an emission level more
stringent than the floor since the technology can control
better than the emission level currently represented by the
permits, and the cost of the technology is reasonable. Refer
to section 7.6.2 for discussion of the cost of requiring
carbon injection.
7.6 IMPACTS OF MUNICIPAL WASTE COMBUSTOR EMISSION GUIDELINES
7.6.1 Energy
Commenter: Several commenters (IV-D-37, IV-D-38,
IV-D-44, IV-D-54, IV-D-64, IV-D-69, IV-D-80) urged the EPA to
consider the energy impact that will result from
implementation of the proposed rule. One commenter (IV-D-44)
argued that the EPA has not adequately considered the energy
impacts of proposing guidelines more stringent than the MACT
floor. The commenters explained that where plants close
either temporarily or permanently because of the high cost of
the retrofit, localities will need to find alternative energy
options. One commenter (IV-D-44) claimed that EPA's energy
impacts analysis is very general and should address this
specific type of energy impact. One commenter (IV-D-80)
pointed out that the National Energy Strategy states the need
to "...encourage the conversion of MSW to energy...".
Response: The EPA's modeling of the economic impacts of
the proposed regulation on existing plants does take into
account the potential losses of energy revenue due to downtime
during retrofit (temporary closings), although these costs are
not explicitly broken out from the total capital costs
reported in the EIA. The national capital costs estimates
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include the cost of equipment as well as downtime costs
attributable to lost energy revenue and to increased waste
disposal costs, which were calculated for each model plant.
Furthermore, the electricity impacts estimated on a TJ/year
basis for the guidelines represent a very small portion of the
electricity generated at MWC's (i.e., less than 10 percent),
and the natural gas impacts are negligible.
The EPA does not expect any permanent plant closings
resulting from implementation of the emission guidelines to
cause significant energy impact. The MWC plants most likely
to close are older MWC plants that do not generate
electricity. Additionally, MWC plants are not major power
producers. Large MWC plants produce only around 7 0 MW of
electricity. If a county does close an MWC plant due
implementation of the guidelines, the county may choose to
purchase electricity from the national electricity grid
system.
7.6.2 Cost and Economic
Comment: Several commenters (IV-D-28, IV-D-37, IV-D-38,
IV-D-43, IV-D-44, IV-D-54, IV-D-80) contended that the EPA has
underestimated the cost of the proposed guidelines. Several
commenters (IV-D-28, IV-D-37, IV-D-38, IV-D-43, IV-D-54,
VI-B-04) provided examples of the cost of the proposal for
specific MWC plants. The commenters indicated that the
proposed emission guidelines would cost from $4 million to
$136 million for specific existing MWC plants that would be
subject to the guidelines.
Response: The cost estimates developed prior to proposal
are representative for typical plants. The cost estimates for
17 model plants chosen to represent different sizes, types,
and ages of existing facilities are contained in the document
entitled "Economic Impact Analysis for Proposed Emission
Standards and Guidelines for Municipal Waste Combustors"
(EPA-450/3-91-029, March 1994). Capital costs of controls
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were developed from information provided by vendors for
control equipment designed to be applicable to MWC's.
Installation costs were included. Retrofit factors were used
to account for increased costs due to site access constraints
and congestion. For most model plants, a factor of 1.25 was
used, representing a "medium" difficulty case. For some
models, a factor of 1.42 was used to represent a very limited
space and access. "Scope adder" costs for modifying ducts and
stacks, demolition, and replacement were also included where
appropriate.
The capital costs cited by some of the commenters are
consistent with EPA's estimated capital costs to comply with
the guidelines. The EPA's estimate of capital costs for
retrofitting acid gas/PM control for achieving the guideline
emission levels for acid gases and PM for three large model
MWC plants (i.e., each of the model plants is mass burn and
has three units, from 300 to 750 tons/day unit capacity) range
from $14 million to $31 million, depending on the difficulty
of the retrofit. The $14 million capital cost value
represents the cost for a plant that already has an ESP
achieving the guideline PM level, but requiring an SD. The
EPA estimates $21 million for a plant with an existing ESP not
achieving the guidelines level for PM to upgrade its system to
meet the PM level, and retrofit with an SD. The $31 million
value is the EPA's estimate of the cost to add an SD and
replace an existing ESP with an FF. These costs are provided
in the memorandum "Analysis of Acid Gas Control System Cost-
Effectiveness for Existing MWC's," August 24, 1990. The EPA
expects these estimated capital costs to be mid-range and
accurate within a factor of 3. The EPA expects the cost to
comply with the proposal to vary depending on site-specific
factors at individual facilities. The EPA contacted commenter
IV-D-28 to see if a cost breakdown was available for some of
the higher retrofit cost examples provided, in order to
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compare the commenter's cost estimates (which were provided
only as a total retrofit cost value) to the EPA's cost
estimates. The commenter indicated that a cost breakdown was
not likely available and did not provide any breakdown of
total retrofit costs. In any case, the EPA expects that its
capital cost estimates are mid-range, and that the retrofit
cost for some individual facilities will vary.
Comment: Several commenters (IV-D-28, IV-D-34, IV-D-37,
IV-D-43, IV-D-44, IV-D-54, IV-D-55, IV-D-67, IV-D-88, IV-D-87,
IV-D-98) argued that the EPA had underestimated the cost of
N0X control for existing MWC plants. One commenter (IV-D-87)
reported estimates of capital expenditures for retrofits that
range from $1 million to $1.5 million per boiler, with
associated operating expenses of approximately $200,000/year.
One commenter (IV-D-37) indicated that Pinellas County has
estimated the capital costs of a NOx control system to be $4
million. The commenter added that the modifications to
boilers will add about $1 million to the capital costs and
that annual operating costs are estimated at $2.2 to
$3.1 million. One commenter (IV-D-88) stated that it would
cost in excess of $1 million to control NOx to the MACT floor
level of 215 ppmv or to the selected MACT level of 180 ppmv.
One commenter (IV-D-87) indicated that vendor quotes for the
capital and operating costs for NOx control vary from $2,521
to $7,000 per ton of NOx removed. Another commenter (IV-D-55)
indicated that vendors provided cost estimates indicating an
average cost increase of an SNCR retrofit of $3.40/Mg of MSW
combusted. Four commenters (IV-D-34, IV-D-43, IV-D-44,
IV-D-67) argued that EPA's costing data for applying NOx
controls to existing facilities are based on data for
application of a system to a facility that incorporated this
system into its original design. The commenters urged the EPA
to perform further tests and research to determine whether
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there are major economic impediments to applying the N0X
guideline to existing plants.
Two commenters (IV-D-28, IV-D-87) pointed out that the
EPA considered the cost to purchase and install SNCR equipment
but that the EPA did not consider the cost to properly store
and manage the storage of a chemical such as ammonia, the
"potential environmental costs" of the control equipment, and
the increased operating costs associated with the proper
operation of the SNCR system. One commenter (IV-D-98) stated
that the EPA did not consider the added costs of mitigating
ammonia slip hazards, or of complying with other regulations
[e.g., SARA title III; section 112(r)] triggered by the
presence of substantial amounts of ammonia stored and used
onsite.
One commenter (IV-D-98) criticized the EPA's costing
analysis for N0X control because it has not been significantly
updated since the 1989 subpart Ea proposal notice, and because
the only memorandum providing updated information is not
well-founded. The commenter criticized the September 24, 1991
memorandum "N0X Control on Existing MWC's" because it
concludes, without any analysis, the following: "To account
for additional costs associated with [SNCR] retrofit
difficulty, equipment costs were multiplied by a retrofit
factor of 1.25." The commenter points out that the only
source for this conclusion is a November 30, 1990 telephone
conversation with one major SNCR vendor.
Response: For the most part, the costs for NOx control
provided by the commenters are not different from the EPA's
NOx control cost estimates for the proposal. Refer to the
memorandum entitled "NOx Control on Existing MWC's," dated
August 23, 1991, for the EPA's costing analysis for NOx
control. As shown in table 5 of that memorandum, the EPA's
capital cost estimates for NOx control using SNCR using the
Thermal DeNOx™ process with aqueous ammonia range from
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$1.8 million for a 450 Mg/day plant with 2 units to $4.8
million for a 2,050 Mg/day plant with 3 units. The annualized
costs for these two plants are estimated to be about $470,000
and $1.4 million, respectively. The estimates for the
Pinellas MWC provided by one commenter are not significantly
higher than would be estimated by the EPA for a plant such as
Pinellas with capacity of 2,700 Mg/day and 3 units.
Additionally, the EPA's estimate of the cost per ton of MSW
ranged from $1.82/ton of MSW to $3.40/ton of MSW for plants
all of the model plants identified by the EPA with capacities
greater than 380 Mg/day. The $/ton of NOx removed and $/ton
MSW values provided by the commenters are within the range of
values estimated by the EPA prior to proposal.
In estimating the cost of SNCR for application to
existing plants, the EPA did investigate the possibility of
there being difficulty in retrofitting an SNCR system to an
existing plant. The EPA found that, in general, facilities
should face no difficulty in retrofitting SNCR systems. Prior
to proposal, the EPA included in its cost estimates for NOx a
retrofit factor of 1.25 to account for the additional cost to
add SNCR to an existing facility (e.g., the cost of installing
ports and tube bending). After proposal, the EPA contacted an
additional vendor of SNCR systems to further investigate the
use of this retrofit factor, and found that the vendor
indicated that there is very little difference in the
difficulty of installing an SNCR system into an existing plant
versus a new plant. The vendor indicated that the cost of
installing ports and tube bending would average $120,000
(refer to memorandum entitled Telephone Conference Between
Denise Bevington and David White, Radian Corporation and Rich
Pickens, Nalco Fuel Tech, April 27, 1995.) This estimate is
less than the EPA's cost estimate at proposal, using a
retrofit factor of 1.25 applied to the equipment costs to
calculate capital cost for existing plants. In fact, because
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the EPA's retrofit cost estimate may be high, it may reflect
retrofit conditions that are more difficult and costly than
are average.
The EPA's analysis of N0X control costs are based on use
of the Thermal DeNOx process with aqueous ammonia injection.
Both aqueous ammonia and urea (used with the NOxOUT™ process)
may be stored and used safely, and do not have the safety
hazards and costs associated with the use of anhydrous ammonia
(i.e., the regulatory costs associated with SARA title III and
section 112(r) of the Act.) Additionally, at the level of N0X
control required by the final guidelines, ammonia
concentration in the ash and ammonia slip have not been
demonstrated to be a problem.
The EPA prepared its pre-proposal costing analysis for
N0X in August of 1991 and considers the analysis to be
representative of N0X control costs at proposal. Since the
EPA prepared that memorandum, the Office of Research and
Development of the U.S. EPA and the U.S. Department of Energy
funded a study in 1994 of N0X control technologies, entitled
"N0X Control Technologies Applicable to Municipal Waste
Combustors," EPA-600/R-94-August 1994. The study assessed the
cost of a conventional SNCR system based on injection of
aqueous ammonia as a liquid. The study indicated that the
costs of a urea-based system are similar. The study estimates
capital costs of $800,000 for a 400 tons/day unit. Using a
retrofit factor of 1.25, and applying it to the total process
capital cost included within the $800,000 capital cost, the
total capital cost for retrofiring this system on an existing
plant would be estimated to be $900,000. For a facility with
two units, the cost would be $1.8 million. In EPA's 1991
study of NOx control costs, the estimated capital cost for a
600 tons/day plant with two units is $2.3 million, which is
$0.5 million higher than the more recent estimate of the cost
for a larger plant. Therefore, the EPA considers its cost
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estimates for N0X to be representative of the cost at
proposal.
Comment: One commenter (IV-D-87) said the entire cost
analysis is faulty because it assumes that SNCR will be needed
to meet the floor, which is not accurate. The commenter noted
that the Mid-Connecticut MWC, which was studied by the EPA in
1989, would be able to meet the MACT floor of 215 ppm with no
additional controls. The commenter argued that it would be
necessary for MWC's to add SNCR to meet a guideline of
180 ppm. The commenter argued that this requirement would
represent a large cost that the EPA must include in the
incremental cost analysis.
Response: The EPA agrees with the commenter that some
MWC facilities may be able to achieve the proposed floor level
of NOx control without utilizing SNCR. As further discussed
in section 7.5.5 of this document, the NOx limit for large
facilities was revised based on subcategorization by combustor
type. The revised MACT limits being promulgated for NOx at
large plants are as follows: 200 ppmv for mass burn waterwall
combustors; 250 ppmv for mass burn rotary waterwall
combustors; 250 ppmv for refuse-derived fuel combustors;
240 ppmv for fluidized bed combustors; uncontrolled for mass
burn refractory combustors; and 200 ppmv for other combustors
not listed above. These limits are equivalent to the MACT
floor for each combustor type and require no additional
control technology other than that needed to achieve the MACT
floor. As a result of this change in the NOx guidelines, the
cost of the NOx guidelines is considered to be reasonable.
Comment: Three commenters (IV-D-44, IV-D-54, IV-D-80)
argued that the EPA must consider certain specific costs of
the proposal that are not included in the EPA's economic
impact analysis. One commenter (IV-D-44) contended that the
EPA's discussion of cost impacts must address increased
operating costs, such as the cost of additional reagents and
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costs for risks assumed by the vendors to meet higher
performance levels, and hidden costs, such as changing
technologies for which debt service continues to be owed. Two
commenters (IV-D-54, IV-D-80) contended that the EPA must
consider additional operational expenses related to labor,
repairs, and reduced equipment life. The commenter asserted
that these operational expenses are significant concerns due
to the low gas temperatures and accelerated corrosion rates
that would accompany the proposed pollution control
technology.
Response: Regarding reagent costs, the EPA's costing
analysis included the cost of reagents required to meet the
guidelines (i.e., carbon, lime, and aqueous ammonia.) There
will be no cost for vendors taking "risks" to support the
guidelines because vendors have reviewed the guideline
pollutant emission levels and have indicated that their
technologies can achieve those levels. Regarding debt owed on
equipment replaced to meet the guidelines, the EPA considered
this problem in establishing the guidelines emission levels;
however, the cost of paying the debt on equipment replaced as
a result of the guidelines is not a cost that the EPA includes
in its analysis of capital and incremental costs. The final
guidelines are based on use of ESP's or FF's, such that many
existing ESP's will not need to be replaced in order to comply
with the MWC guidelines. It has not been demonstrated that
the guideline emission levels will result in accelerated
corrosion rates due to the low gas temperatures required to
achieve the guidelines, especially in light of the reduced
acid gas emission levels that will accompany the low gas
temperatures to achieve the guidelines emission levels for
acid gases.
Comment: Several commenters (IV-D-18, IV-D-37, IV-D-38,
IV-D-44, IV-D-54, VI-B-03, VI-B-04) argued that the EPA must
consider the direct and indirect costs of the guidelines on
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communities due to closing MWC plants either temporarily for
retrofits or permanently. One commenter (IV-D-18) stated that
some plants will not have the space necessary to avoid
significant downtime. One commenter (VI-B-04) indicated that
their facility would be down for 6 months to perform the
required retrofit. The commenter (VI-B-04) estimated that the
cost to landfill approximately 175,000 tons of waste during an
estimated 6-month downtime would cost $2,625 million.
Three commenters (IV-D-44, VI-B-03, VI-B-04) argued that
municipalities in which the MWC closes as a result of the
emission guidelines would face the costs of alternative waste
disposal and lost investment in the closed MWC plant. One
commenter (VI-B-03) explained that, in their case, landfill
space is limited and their community does not have access to
municipal transfer station facilities, such that they would
need to contract for disposal services, which would represent
a significant added cost for long distance transportation of
MSW.
Several commenters (IV-D-37, IV-D-38, IV-D-54, VI-B-03,
VI-B-04) mentioned the lost energy revenues for WTE plants as
an added cost. Three commenters (IV-D-37, IV-D-38, VI-B-04)
provided an example of the cost impact for specific MWC
plants. One commenter (IV-D-37) stated that the county that
owns the Pinellas, Florida MWC plant will lose $18.1 million
annually from energy sales ($8.5 million) and "capacity sales"
($9.6 million) to Florida Power Corporation. Another
commenter (IV-D-38) stated that the county that owns the
Tampa, Florida MWC plant will lose $4.2 million annually from
energy sales. One commenter (VI-B-04) indicated that the
Tulsa, Oklahoma plant would lose $3.2 million in steam and
recovered materials sales during an estimated 6-month
downtime. One commenter (IV-D-54) stated that many MWC plants
in Minnesota have long-term electric and steam contracts, the
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requirements for which would have to be met in another more
costly way.
Response: Regulatory costs due to downtime (temporary
closure) of existing plants for retrofit will have cost
impacts, and EPA addressed these cost impacts as part of the
total capital costs of the regulation. The national capital
cost estimates include the cost of equipment as well as
downtime costs attributable to both lost energy revenue and
increased waste disposal costs (offsite disposal), which were
calculated for each model plant. Downtime costs were
estimated based on downtime estimates which ranged from 0 to
6 months depending on the model plant and control option. The
actual downtimes or costs associated with them may vary;
however, this is only one of many costs which were factored
into the impact analysis. The cost used for the diversion of
waste to other disposal alternatives (i.e., $60/Mg) may now be
considered high, and actual costs for the diversion of MSW may
be closer to $50/Mg, given changes in tipping fees. This
would reduce the retrofit cost assumed by the EPA in its
impacts analysis.
The EPA did not consider the cost of the proposal due to
permanent closings of MWC's. The EPA expects that most of the
MWC's that will close are older plants that do not produce
electricity, such that there would be no significant loss in
revenues for energy production. Refer to section 3.6.2 for
further discussion on this issue.
Comment: Two commenters (IV-D-13, IV-D-44) contended
that EPA's cost-benefit analysis for requiring carbon
injection on MWC units at small MWC plants significantly
underestimates the cost to these plants. One of the
commenters (IV-D-13) explained that during the 1980's, the
Hampton/NASA MWC plant spent $1 million to reduce its
dioxin/furan emissions by 99 percent (using good operating
practices), to a level of 2.19 ng/dscm TEQ. Both commenters
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contended that capital costs and annual operating costs to
implement dry sorbent injection and carbon injection to
achieve the dioxin guideline would be unreasonably high. One
of the commenters (IV-D-44) stated that the high cost for
dioxin control contradicts the EPA's contention that costs fo
additional control beyond the floor are minimal.
Response: The high cost referred to by the commenters i
due primarily to the cost of retrofitting a DSI for acid gas
scrubbing. Acid gas scrubbing using a DSI system is required
to meet the floor level of control for SO2; therefore, the
cost to retrofit an acid gas scrubbing system is mandated by
section 129 of the Act. Additionally, since proposal, the
dioxin/furan limit for small MWC plants has been revised to
125 ng/dscm total mass, so the facility referred to by the
commenter may be able to meet the final guideline without
carbon injection. Refer to section 7.5.2 for further
discussion of the revised dioxin/furan limit.
Comment: Several commenters (IV-D-06, IV-D-08, IV-D-11,
IV-D-37, IV-D-38, IV-D-40, IV-D-43, IV-D-44, IV-D-58, IV-D-62
IV-D-62, IV-D-68, IV-D-95, IV-D-99, IV-D-104, IV-D-114,
IV-D-127, IV-D-128, IV-D-129, IV-D-130, IV-D-131, IV-D-132)
expressed concern that the EPA has not taken into account the
cost of achieving the proposed emission reductions where the
guidelines have been set at a level more stringent than the
MACT floor. Three commenters (IV-D-43, IV-D-44, IV-D-104)
argued that the EPA did not provide cost justification for
selecting guideline levels more stringent than the MACT floor
Response: For both small and large MWC plants, acid
gas/PM control using DSI/ESP for small plants and SD/ESP or
SD/FF for large plants will be required to achieve the floor
and MACT levels of control for SO2 and PM. Refer to
sections 7.4 and 7.5 of this document for further discussion
of the final MACT floor levels and final MACT levels for each
pollutant. Therefore, the cost for acid gas/PM control to
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achieve the final guideline emission limits for SO2, HC1, PM,
Cd, Pb, and dioxins/furans is required by the MACT floor,
which is the least stringent emission level mandated by
section 129 of the Act. At proposal, the EPA determined that
the incremental cost to add activated carbon to the acid
gas/PM control device to reduce Hg to the proposed and final
guideline emission levels of 0.080 mg/dscm would be less than
$1.00 per Mg of MSW combusted for large plants and $1.40 per
Mg of MSW combusted for small plants. The EPA concluded that
this cost is reasonable given the concerns over the toxicity
and bioaccumulation of Hg in the environment.
Comment: Several commenters (IV-D-06, IV-D-08, IV-D-11,
IV-D-40, IV-D-58, IV-D-59, IV-D-62, IV-D-63, IV-D-86, IV-D-92,
IV-D-95, IV-F-99, IV-D-100, IV-D-106, IV-D-110, IV-D-114,
IV-D-116, IV-D-117, IV-D-127, IV-D-128, IV-D-129, IV-D-130,
IV-D-131, IV-D-132) expressed concern about the cost impact
that the proposed guidelines will have on city/county budgets.
In contrast, one commenter (IV-D-32) indicated that the
guidelines will not be unduly burdensome or costly for MWC
plants because they are well within the capabilities of
existing control technologies. Some of the commenters
questioned whether the EPA understands the price that will be
paid by local governments. The commenters explained that the
proposed guidelines will cause money to be removed from other
essential city-funded services and would dismantle States'
integrated solid waste management approaches. Several
commenters emphasized this point with regards to the economic
impact on small combustors serving small communities and
stated that the proposal is "pro-big business" The commenters
questioned whether the benefit of implementing the guidelines
would outweigh the resulting cost to cities, through cutbacks
in other city programs, such as health and safety. Two
commenters pointed out that the WTE industry is already one of
the cleanest power producing groups in the country, such that
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the proposal will provide only a marginal benefit in emissions
reduction.
Response: The EPA recognizes that the emissions
guidelines will impact city/count budgets; however,
section 129 of the Act requires that MACT standards be
established for small plants, with the minimum level of
control to be established at the MACT floor. For all
pollutants except Hg and dioxins/furans, the final guidelines
are set at the minimum level required by section 129 (i.e., at
the MACT floor level.) As discussed above in this section,
the final emission guidelines for small plants would require
acid gas/PM control to achieve the MACT floor for SO2 and PM.
The only pollutant emission level established at a level more
stringent than the floor that will result in additional cost
to small plants is Hg. As discussed above in this section,
the incremental cost of $1.40 per Mg of MSW combusted is
considered to be reasonable in light of the emission reduction
benefit.
In preparing the guidelines for small plants, the EPA was
particularly concerned about the impacts on small entities.
To address these concerns, several measures designed to
mitigate the impacts on small entities were considered. The
emission guidelines consist of emission limits, as opposed to
design, equipment, work practice, or operational standards,
giving the MWC owners and operators the freedom to select the
most successful economic means of reducing emissions. The
emission guidelines will apply only to MWC plants with
capacity of greater than 35 Mg/day. This cutoff eliminates
from the purview of the guidelines the overwhelming majority
of existing very small MWC plants. The guidelines are
"tiered" so that the stringency (and therefore potential
economic burden) of the emission guidelines
increases as the size of the MWC plant increases. Small
plants would be required to perform performance testing, but
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the guidelines and performance testing requirements would not
be as stringent as those for large plants (e.g., performance
testing is required less frequently.) Additionally, small
plants are not required to control N0X.
Overall, the emission guidelines will not apply directly
to any MWC's, but will be used as a guide by individual State
air pollution control agencies in developing site-specific
regulations for MWC's. States are allowed some flexibility in
implementing the guidelines.
7.7 PERFORMANCE TEST METHODS AND MONITORING PROVISIONS FOR
MUNICIPAL WASTE COMBUSTOR EMISSIONS
7.7.1 Continuous Monitoring
Comment: One commenter (IV-D-69) said the requirement
for 75 percent availability each day should be eliminated.
The commenter said 90 percent availability per quarter is
achievable, but 75 percent per day is not because of periodic
problems with probes, filters, sample lines, and conditioning
systems that cannot be prevented. The commenter said
sometimes parts not on the manufacturer's recommended spare
parts list must be sent to a plant via overnight mail.
Response: The EPA's data indicate that for 90 percent of
the days in a quarter, 75 percent availability per day is
achievable. In other words, up to a total of 10 percent of
the days per quarter (approximately 9 days) may be used if
necessary to order, ship, and install parts to repair a CEMS.
This should be adequate time.
Comment: One commenter (IV-D-109) recommended that a
95 percent data availability is reasonable and necessary to
ensure compliance on a continuous basis. The commenter
informed the EPA that the Ohio EPA has a CEMS program that
includes approval, certification, computer tracking of data,
and independent audits of systems on a statewide basis. The
Ohio EPA has tracked data availability for over ten years and
currently has over 125 plants monitoring continuously across
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the State. The commenter said plants must maintain 95 percent
or better data availability, and approved routine maintenance
(e.g., daily calibration checks, quarterly linearity checks,
cylinder gas audits, relative accuracy tests, etc.) do not
count as monitor downtime. The commenter asserted that the
data indicate that opacity monitoring systems can actually
achieve 98 percent or better availability. The commenter
noted that if a site experiences a lightening strike, the
major reason for CEMS downtime in Ohio, it may take a week to
get the parts delivered, installed, and operating again.
Response: The EPA agrees that greater than 90 percent
data availability may be achievable per quarter; however, the
EPA's data indicate that 90 percent data availability per
quarter is a more consistently achievable and reasonable
requirement which ensures a properly operating CEMS. States
are free to impose more stringent requirements if they so
choose.
Comment: Two commenters (IV-D-18, IV-D-85) did not want
to have to replace currently certified CEM systems for the
purpose of changing span values. One commenter (IV-D-18) said
the span values should not be arbitrarily set at two times the
emission limit. One commenter (IV-D-85) said that some plants
have been constructed under State regulations more stringent
than the existing or proposed federal standards, and it would
be a waste of time and money to require these plants to change
out the CEMS for the sole purpose of changing the span value.
The commenter suggested that the following wording be added to
the NSPS rule for NOx analyzers which is referenced by the
guidelines: "The span value of the CEM system shall be two
times the level of the emission limit provided in this
section, unless a CEM system has been previously installed,
certified, and operated in accordance with 40 CFR 60,
appendix B." The commenter suggested that similar changes be
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made to the SO2 and the CO requirements in the NSPS which are
referenced by the emission guidelines.
Response: At proposal, the span values for N0X and CO
CEMS were set at twice the level of the applicable emission
limits, and the span values for SO2 CEMS were set at
125 percent of the expected maximum uncontrolled concentration
at the inlet to the control device and 50 percent of the
expected maximum uncontrolled concentration at the outlet of
the control device. In order to ensure that CEMS have span
values appropriate to each individual MWC unit, the NOx and CO
CEMS span values have been revised to 125 percent of the
maximum expected concentration at the point of measurement.
The EPA believes this change assures that the source will be
able to demonstrate compliance with the emission limits, while
providing flexibility to the operator in monitor selection.
There is no change to the SO2 CEMS span values. If previously
installed CEMS meet these requirements, there should be no
need for replacement.
7.7.2 Comments on Proposed Test Methods
Comment: One commenter (IV-D-109) asserted that the
unavailability of audit samples for Method 29 needs to be
addressed by the EPA. The commenter has found that audit
samples are only available a few months out of the year and,
without an audit sample, cannot ensure that the metals
analyses were done properly and that the data generated is
representative.
In addition, the commenter said, the EPA has failed to
establish pass/fail criteria that can be used by the Ohio EPA
to accept or reject the results of metals testing. A detailed
letter describing the problems this has caused is attached to
the comment (attachment G). The commenter was told that with
certain control technologies the amount of PM collected does
not meet the PQL and, therefore, cannot be held to a pass/fail
criteria. The commenter stated that clarification regarding
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PQL's for both the Method 29 collection and the analyses of
samples would be appreciated. The commenter asked the
following question: If a company fails one or more of the
multiple metals being tested, but not all of them, does the
EPA recommend redoing only those metals that did not pass the
audit, or redoing all of them?
Response: Proposed Method 29 has many required internal
Quality Assurance and Quality Control (QA/QC) procedures which
may be used to establish the quality of the data.
Additionally, the specific analytical procedures described by
proposed Method 29 have internal QA/QC of their own.
Therefore, sufficient quality of the data can normally be
established without the requirement of the use of audit
samples. The use of an audit sample, if commercially
available, would be an optional procedure.
In response to the second general comment, proposed
Method 29 describes in detail in section 2.3 a mechanism for
determining in-stack detection limits based on total volume of
gas sampled and analytical procedures, and should be applied
for test planning and evaluation purposes.
Comment: One commenter (IV-D-55) questioned the EPA's
conclusions regarding the superiority of Method 29. The
commenter said that the EPA concluded in a 1991 comparison
study by OAQPS that Method 101A might miss measuring small
amounts (3 percent) of mercury based on the fact that some
Method 29 results reported higher values. The commenter
asserted, however, that the 1991 comparison study failed to
account for the data points where Method 101A reported higher
average concentrations of mercury than Method 29.
Response: The selection of Method 29 over Method 101A
was based on recognized statistical evaluation techniques, as
reported in the subject document, which can be found in the
docket. Correction factors reported in that study for the
Method 101A comparative data ranged from 1.14 to 1.49,
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depending on source operation. Method imprecision in methods
that are statistically shown to be different can cause an
overlay of the data sets.
Comment: One commenter (IV-D-09) questioned whether
current performance testing technology is sufficient to
measure dioxin/furan emissions at the low levels proposed.
Response: Both the proposed dioxin/furan limits
(30 ng/dscm for large plants and 60 ng/dscm for small plants)
and the final dioxin/furan limits (30 ng/dscm for non-ESP
equipped units at large plants, 60 ng/dscm for ESP-equipped
units at large plants, and 125 ng/dscm for small plants) are
at levels that are well within the measurement capabilities of
Method 23.
7.8 ENFORCEMENT, REPORTING, AND RECORDKEEPING PROVISIONS FOR
MUNICIPAL WASTE COMBUSTOR EMISSIONS
7.8.1 Enforcement-
Comment : One commenter (IV-D-120), noting that States
have differing responses to documented noncompliance, offered
three suggestions for the EPA to consider to help clarify the
purpose of the requirement that facilities with compliance
schedules longer than 1 year from the date of approval of the
State plan must submit dioxin test results. The commenter
recommended any one of the following suggestions: (1) Delete
this requirement; (2) give specific instructions to States
about what to do with this information; or (3) start the
routine dioxin performance testing sooner than the currently
proposed schedule in 40 CFR 60.58b(g) (3)-(4) .
Response: The purpose of the emission guidelines to
require the facilities with compliance schedules longer than
one year from the date of approval of the State plan to submit
dioxin test results is to help States manage and prioritize
retrofits. Additionally, the schedule and emission reports
will allow States to balance emission levels with the economic
impacts of requiring retrofitting.
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7.8.2 Reporting and Recordkeeping
Comment: One commenter (IV-D-103) recommended that the
requirements pertaining to compliance recordkeeping contained
in § 60.39b(c)(1)(i) through (ix) should be made consistent
with the requirements listed in 40 CFR 60.21(h). Another
commenter (IV-D-120) preferred to see this list of
"suggestions" removed from the proposed emission guidelines
because the general public often misinterprets suggestions as
"musts." The commenter added that if they are kept, the EPA
should stress that they are only suggestions.
Response: The intent of the increments of progress
listed under subpart B - Adoption and Submittal of State Plans
for Designated Facilities (proposed § 60.21(h)), which are
required steps that owners or operators must take to achieve
compliance, and the intent of the measurable and enforceable
activities specified in proposed § 60.39b(c)(1)(i) through
(ix), which are suggested steps to achieve compliance that
owners or operators may take, are the same. Both lists are
consistent with each other. The latter is a list of
suggestions, as clearly stated in the final rule. No
significant change has been made to the final rule with regard
to this comment.
7.9 LEGAL CONSIDERATIONS
Comment: Two commenters (IV-D-85, IV-D-98) argued that
EPA's approach of choosing the average of the top 12 percent
of the units separately for each pollutant when determining
the MACT Floor has resulted in MACT guidelines that are too
stringent. The commenter claimed that available data indicate
that several of the guidelines calculated using this method,
including some set at the MACT Floor level, are not
continuously achievable. Refer to sections 3.5.1 and 7.5.1
for further discussion of the technical issues related to the
comment. Both commenters argued that it is established beyond
question that to satisfy the legal "achievability" criteria of
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sections 111 and 129, the EPA must show that all affected
units will be able to continuously meet the promulgated limits
through proper use of reference control technology under
foreseeable worst-case operating conditions. Refer to
section 3.11 for further discussion of the legal issues
associated with this comment.
Response: This same issues was raised for the NSPS.
Refer to section 3.11 for EPA's response to this comment.
Comment: Two commenters (IV-D-24, IV-D-49) argued that
the EPA has no legal basis for establishing the MACT floor for
existing units based upon permit data, but instead, the
commenters believed that section 129(a)(2) clearly requires
the EPA to derive floors from lower actual emissions data,
when the data are available. One commenter (IV-D-24) further
argued that Congress intended the phrase, "average emission
limitation achieved" in section 129(d)(3) to mean actual
emission rates, and that Congress could not have intended to
refer to permitted emission levels when actual emissions are
lower than permitted levels. The commenter further stated
that the EPA's improper use of regulatory and permit
limitations resulted in MACT floors that were not as stringent
as they should be. The same commenter noted that although
section 302(k) defines emission limitation, that section was
adopted to clarify that emission standards may include work
practice standards in response to a 1978 Supreme Court
decision, and the EPA has never interpreted the phrase to
require it to use permit data when actual emission data are
available. Moreover, the commenter argued that nothing in the
1990 Amendments indicates that Congress intended such a
result.
One commenter (IV-D-44) conversely argued that the EPA
legally is required to establish the MACT floor and MACT for
existing plants based upon permit limits. The commenter
contended that the phrase "emission limitation" in section 129
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is defined in section 302(k) of the Act, and specifically
refers to a regulatory limitation on the quantity, rate, or
concentration of emissions of air pollutants, such as a permit
limitation. Thus, the commenter stated that contrary to EPA's
comments in the preamble to the proposed rule, the EPA does
not have the discretion to set MACT floors based upon permit
data, but is required to do so.
Response: The starting point for analyzing whether the
EPA must apply the section 302(k) definition of emission
limitation in determining MACT floors or actual emissions data
is the "test" set forth in Chevron v. NRDC, 467 U.S. 837
(1984). Under the Chevron test, the reviewing court will
first ask whether Congress has "directly spoken to the precise
question at issue." Chevron, 467 U.S. at 842. If Congress
has not "directly spoken to the precise question at issue,"
the court will proceed to the second prong of the Chevron
analysis, in which it must uphold the Agency's interpretation
if it is a "permissible construction" of the statute. Id. at
843 .
The EPA concludes from its analysis of the statutory
language that Congress has not clearly indicated which
interpretation it intended. The EPA therefore does not agree
with either position taken by the commenters -- i.e., the EPA
does not agree that the language of section 129 clearly
requires it to use regulatory and permit data to set the MACT
floor, or clearly requires it to use actual data.
For example, although the EPA could interpret the statute
as requiring it to apply the definition of emission limitation
in section 302(k) to section 129(a)(2) as suggested by some
commenters, that application would result in a conflict with
the language of section 111(h). Section 302(k) provides:
The terms "emission limitation" and "emission
standard" mean a requirement established by the
State or the Administrator which limits the
quantity, rate, or concentration of emissions of air
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pollutants on a continuous basis, including any
requirement relating to the operation or maintenance
of a source to assure continuous emission reduction,
and any design, equipment, work practice or
operational standard promulgated under this chapter.
42 U.S.C. § 7602(k) (emphasis added). Section 111(h),
however, provides:
For purposes of this section, if it is not feasible
. . . to prescribe or enforce a standard of
performance, . . . [the Administrator] may instead
promulgate a design, equipment, work practice, or
operational standard, or combination thereof, which
reflects the best technological system of continuous
emission reduction which (taking into consideration
the cost of achieving such emission reduction, and
any non-air quality health and environmental impact
and energy requirements) the Administrator
determines has been adequately demonstrated.
42 U.S.C. § 7411(h)(1) (emphasis added). Since 1970,
section 111(a)(1) has incorporated the following language in
its definition of "standard of performance":
[A] standard for emissions of air pollutants which
reflects the degree of emission limitation
achievable through the application of the best
system of emission reduction which (taking into
account the cost of achieving such reduction and any
non-air quality health and environmental impact and
energy requirements) the Administrator determines
has been adequately demonstrated.
See 42 U.S.C. § 7411(a)(1) (emphasis added). The 1977
Amendments of the Act amended the definition of standard of
performance to include a requirement that the Administrator
also must take into account "any nonair quality health and
environmental impact and energy requirements . . .." 42
U.S.C. § 7411(a)(1). Thus, since section 111(h) authorizes
the EPA to promulgate "a design, equipment, work practice, or
operational standard" instead of a performance standard, and
section 111(a)(1) defines a performance standard in terms of
emission limitation achievable, one cannot unequivocally
conclude that Congress intended for the definition of emission
limitation provided in section 302(k) to apply to section 111.
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And since MWC standards are promulgated under both
sections 129 and 111, one cannot unequivocally conclude that
Congress intended for section 302(k) to apply to section 129.
Moreover, such an interpretation is contrary to the
interpretation that the EPA consistently has given to a phrase
in section 111(a)(1) that uses similar terminology. That
section states, "The term 'standard of performance' means a
standard for emissions of air pollutants which reflects the
degree of emission limitation achievable through the
application of the best system of emission reduction . . .."
42 U.S.C. § 7411(a)(1) (emphasis added). Accordingly, the EPA
does not agree with those commenters who stated that the EPA
is required to apply section 302(k) to section 129(a)(2).
The EPA also does not agree with the commenters who
stated that Congress intended for the EPA always to use actual
emissions data to set the MACT floors when the data are
available. For some emission standards, using actual data to
set the MACT floors may be inappropriate based on the facts
applicable to the standard being set. For example, in the MWC
rulemaking, use of actual data resulted in MACT floors that no
MWC unit, nor any technology, could continuously meet.
Section 129(a)(2) requires MACT standards to be at least as
stringent as the MACT floor. 42 U.S.C. § 7429(a)(2). Not
only does the definition of "MACT" emphasize achievable --
i.e., maximum achievable control technology -- but case law
also requires standards promulgated under section 111 to be
achievable "under the range of relevant conditions which may
affect the emissions to be regulated . . .." National Lime
Ass'n v. EPA, 627 F.2d 416, 433 (D.C.C. 1980). An achievable
standard does not have to be one that is already routinely
achieved in industry, but it must be one that is capable of
being met under most adverse conditions which reasonably can
be expected to recur and which are not or cannot be taken into
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account in determining the 'costs' of compliance." Id. at 431
n. 4 6 .
When OAQPS ranked the emissions test data from the large
MWC's in order from lowest emissions to highest emissions, and
then averaged the results from the best performing 12-percent
of units in the category (i.e., the top 29 entries on the
list), the resulting MACT floor is unachievable continuously
by any unit or any technology. This is because a ranking and
averaging of the test data does not account for the
variability in emissions data exhibited by the same unit --
i.e., if five performance tests are conducted on a particular
MWC in 5 years, it is not unusual for one or more of the
annual tests to produce emissions that fall within the best
12-percent of the data, while the remaining annual test data
fall outside this range, even though operating and maintenance
conditions remain the same. Thus, the EPA concludes that
Congress did not intend for the EPA to always use actual
emissions data to set MACT standards, because Congress would
not have intended for the EPA to promulgate standards that are
at least as stringent as the MACT floor, when the MACT floor
itself is not achievable continuously.
As the above discussion establishes, Congress has not
"directly spoken to the precise question at issue" [Chevron,
467 U.S. 837 (1984)] -- namely, whether it intended for the
EPA to apply the definition of section 302(k) to section 129
when setting the MACT floors as one commenter has asserted, or
actual emissions data when the data are available as other
commenters have asserted. In the MWC rulemaking, however,
only one of the two interpretations resulted in MACT floors
that are achievable continuously under the range of relevant
conditions that may affect the emissions the rule regulates.
The EPA thus determined MACT floors for MWC's using regulatory
and permit limitations that actually have been achieved in
practice.
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7.10 COMPLIANCE TIMES FOR MUNICIPAL WASTE COMBUSTOR EMISSIONS
NOTE: The issue of compliance schedules for completing
retrofits (or closure) to comply with the guidelines is
discussed in the promulgation preamble.
Comment: Five commenters (IV-D-43, IV-D-44, IV-D-66,
IV-D-67, IV-D-86) disagreed with an accelerated compliance
schedule for Hg and dioxins/furans, while two commenters
(IV-D-74, IV-D-103) argued that all large MWC plants which
already have SD/ESP or SD/FF control systems should be
required to comply with the accelerated compliance schedule
regardless of commencement of construction dates. For MWC
plants constructed after June 26, 1987, two of the commenters
(IV-D-43, IV-D-44) suggested an 18-month timeframe, and one
other commenter (IV-D-67) suggested a 24-month timeframe,
would be more reasonable to meet the emission guidelines for
Hg and dioxins/furans than the proposed 1 year timeframe. Two
commenters (IV-D-66, IV-D-86) recommended compliance within
3 years following approval of the SIP. These commenters
disagreed with an accelerated compliance schedule for Hg and
dioxins/furans by arguing that: (1) An accelerated schedule
does not allow for consideration of integrated systems or new
technologies which may offer cost savings to municipalities,
(2) compliance schedules should not be based on public
perception (the commenter cited recent public concern with
potential emissions of dioxins/furans from MWC's - refer to
section 6.1 for more discussion on this issue) but rather on a
realistic appraisal of the implementation time required, and
(3) the different compliance schedules proposed create
"regulatory uncertainty."
Response: An accelerated compliance schedule will be
retained in the final rule for MWC units for which
construction, modification, or reconstruction commenced after
June 26, 1987 and that are located at existing large MWC
plants. However, the proposed 1-year accelerated compliance
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schedule has been extended to 18 months in the final rule.
The rationale for an accelerated compliance schedule is as
discussed in section IV.I of the proposal preamble to the
emissions guidelines. Since all MWC units at large MWC plant
permitted since June 26, 1987 have been subject to NSR and
are, therefore, already equipped with the appropriate acid
gas/PM control devices for dioxin/furan and Hg control (i.e.,
SD/ESP or SD/FF), it was concluded that it would be reasonabl
to require that the Hg and dioxin/furan limits be complied
with according to an accelerated schedule (i.e., many plants
will need to retrofit carbon injection) in order to achieve
additional dioxin/furan and Hg emission reductions as soon as
possible. In response to public comment, the proposed 1-year
accelerated compliance schedule has been extended to 18
months. Additionally, to allow more flexibility, the
scheduling provisions were revised to allow for compliance
with Hg and dioxin/furan limits by 18 months after either
approval of the State plan or issuance of a revised
construction operating permit (if a permit modification is
required), whichever is later. The wording of the final rule
has been revised to reflect these changes.
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8.0 EMISSION GUIDELINES - MATERIALS SEPARATION PLAN
Comment: Of the 25 comments received discussing the
EPA's proposal to include a materials separation plan in the
emission guidelines, 7 commenters (IV-D-24, IV-D-49, IV-D-65,
IV-D-73, IV-D-74, IV-D-103, IV-D-109) supported the proposal
and 18 commenters (IV-D-28, IV-D-37, IV-D-38, IV-D-41,
IV-D-44, IV-D-55, IV-D-56, IV-D-66, IV-D-67, IV-D-71, IV-D-85,
IV-D-86, IV-D-87, IV-D-96, VI-B-02, VI-B-04, VI-B-05, VI-B-06)
were not in favor of the proposal. Reasons commenters
supported the proposal included the following: (1) it may
result in emission reductions at little cost; (2) materials
separation is necessary for proper operation of MWC's; (3) the
proposed plan would be the only way to reduce MSW;
and (4) materials separation could save society money.
Reasons commenters objected to the proposal included the
following: (1) It was not specific enough in its
requirements; (2) materials separation plans could disrupt the
flow of MSW to MWC's; (3) it would be economically
prohibitive; (4) there is no technical basis to demonstrate
that materials separation would reduce MWC emissions or the
risk to the public; (5) the EPA does not have statutory
authority under the Act to establish materials separation plan
requirements for existing MWC's; (6) materials separation
would be more effectively institute if applied to all MSW
management activities in an integrated program under RCRA; and
(7) material separation requirements are better addressed by
local solid waste management plans.
Response: Material separation requirements will not be
part of the final emission guidelines. The EPA requested
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comments on the possibility of including material separation
requirements in the final guidelines. Based on public comment
and further consideration of requiring material separation for
existing plants, the EPA concluded that this type of
requirement would be overly burdensome for existing plants.
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9.0 EMISSION GUIDELINES - FUGITIVE ASH EMISSIONS
Refer to chapter 5.0 for a discussion of all significant
legal and technical issues raised by commenters on the subject
of fugitive ash emissions.
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10.0 MISCELLANEOUS COMMENTS ON MUNICIPAL WASTE COMBUSTOR
EMISSIONS GUIDELINES
This chapter includes miscellaneous comments made
specifically about the proposed emission guidelines. Comments
that were made about both the NSPS and emission guidelines
regarding the health effect of dioxins/furans and Hg,
procedural issues, and other miscellaneous issues are not
duplicated in this chapter. The reader is referred to chapter
6.0 for additional comments on these issues.
10.1 PROCEDURAL
Comment: One commenter (IV-D-101) claimed that the
July 1, 1993 40 CFR 60 already contained a subpart Cb
(Emission Guidelines and Compliance Times for Sulfuric Acid
Production Units) and questioned the Cb designation for this
proposed rule.
Response: The emission guidelines and compliance times
for Sulfuric Acid Production Units have been moved to
subpart Cd of 40 CFR 60 to allow placement of this rule under
subpart Cb. This redesignation of subpart Cb to Cd is
specified in the same Federal Register notice in which the
final NSPS and emission guidelines are published.
10.2 MISCELLANEOUS
Comment: One commenter (IV-D-80) recommended that
product formulation controls be considered as a potential
method of pollution control in lieu of the more costly means
proposed. The commenter argued that it would be most prudent
to control certain metals such as Pb, Cd, and Hg at the
source, where control is efficient and cost effective. The
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commenter claimed there has been no national effort to control
toxic materials in consumer products.
Response: Other efforts are underway to minimize the use
of these metals; however, these guidelines are complying with
section 129 which addresses MWC's and not product and material
manufacturers.
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11.0 WITHDRAWAL OF THE 1991 MUNICIPAL WASTE COMBUSTOR
EMISSION GUIDELINES (SUBPART Ca)
Comment: Several commenters (IV-D-28, IV-D-37, IV-D-38,
IV-D-41, IV-D-56, IV-D-99, VI-B-02, VI-B-05, VI-B-06, VI-B-07,
VI-B-08, VI-B-09, VI-B-10, VI-B-12, VI-B-13) expressed support
for the proposed withdrawal of the 1991 emission guidelines
under subpart Ca. Several commenters (VI-B-08, VI-B-09,
VI-B-10, VI-B-12, VI-B-13) stated that this withdrawal will be
consistent with section 129 of the Act, which requires that
certain pollutants be added to the guidelines and that the
guidelines be based on MACT rather than BDT. One commenter
(VI-B-13) stated that it was Congress' intent in writing
section 129 that the proposed guidelines would supersede the
1991 guidelines. One commenter (VI-B-13) stated that the EPA
is making a necessary "policy decision" in making a tradeoff
between timing and stringency. Two commenters (IV-D-28,
VI-B-13) explained that this withdrawal will avoid a situation
where there are two separate retrofit schedules for
subparts Ca and Cb. Several commenters (IV-D-99, VI-B-08,
VI-B-09, VI-B-10, VI-B-12, VI-B-13) supported the withdrawal
to avoid a situation where local governments must
"double-retrofit" facilities to comply with two different
requirements, which would be prohibitively costly. One
commenter (IV-D-56) indicated that since most States have not
adopted SIP's to implement the 1991 rule, the compliance
schedule would not have been met by most operating facilities
anyway. The commenter supported the withdrawal of the 1991
guidelines to circumvent noncompliance issues associated with
the 1991 schedule. One commenter (VI-B-07) requested that the
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EPA promptly proceed with the final withdrawal, since States
are in an awkward position of defending why their State rules
were not completed.
Response: The EPA agrees with the commenters that the
1991 subpart Ca emission guidelines should be withdrawn at the
same time that these final subpart Cb guidelines are
implemented. The withdrawal of subpart Ca is accomplished in
the same Federal Register notice as the promulgated subpart Cb
guidelines.
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12.0 UNFUNDED MANDATES REFORM ACT AND EXECUTIVE ORDER 12875
Comment: Several commenters (IV-D-06, IV-D-08, IV-D-09,
IV-D-10, IV-D-11, IV-D-13, IV-D-2 8, IV-D-34, IV-D-37, IV-D-38,
IV-D-4 0, IV-D-41, IV-D-43, IV-D-44, IV-D-54, IV-D-55, IV-D-58,
IV-D-62, IV-D-67, IV-D-80, IV-D-82, IV-D-87, IV-D-88, IV-D-95,
IV-D-96, IV-D-99, IV-D-104, IV-D-117, VI-B-02, VI-B-03,
VI-B-04, VI-B-05, VI-B-06) pointed out that the proposed
emission guidelines is an unfunded mandate and that the EPA
violated this mandate with its proposal. One commenter
(IV-D-87) contended that the EPA violated the executive order
by proposing limits more stringent than the MACT floor.
Several commenters (IV-D-67, IV-D-87, IV-D-88, IV-D-96)
explained that the purpose of the executive order is to reduce
the imposition of unfunded mandates upon State, local, and
tribal governments. Several of the commenters (IV-D-06,
IV-D-08, IV-D-11, IV-D-4 0, IV-D-58, IV-D-62, IV-D-80)
contended that the EPA should address the "checks and balances
detailed in Executive Order 12875" before setting standards
more stringent than the MACT floor.
Several commenters (IV-D-28, IV-D-34, IV-D-43, IV-D-44,
IV-D-67, IV-D-95, VI-B-03) cited or referred to the contents
of Section 1 of Executive Order 12875 as the following: "no
Agency shall promulgate any regulation that is not required by
statute and that creates a mandate on local government unless:
(1) the funds necessary to implement the mandate are provided
by the Federal government; or (2) the Agency consults with the
effected governments, addresses their concerns and documents
the Agency's position supporting the need to issue the
regulation containing the mandate." Several commenters
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criticized the EPA for not complying with the latter
requirement, as discussed below.
Two commenters (IV-D-28, VI-B-04) pointed out that
various associations (e.g., SWANA and NLC) have been consulted
by the EPA in drafting the proposal, and that throughout these
consultations, these associations have urged the EPA to
promulgate final regulations that are both (1) protective of
human health and the environment and (2) cost effective, given
the level of proven commercially available control technology.
Three commenters (IV-D-28, IV-D-41, IV-D-69) implied that the
EPA did not address the effected government's concerns. Three
commenters (IV-D-28, IV-D-41, IV-D-69) contended that the
proposed emission guidelines are based on costs that are
clearly excessive and that have not been justified by the EPA,
and two commenters (IV-D-28, IV-D-69) contended that the
proposed emission guidelines do not protect human health and
the environment.
Several commenters (IV-D-09, IV-D-28, IV-D-34, IV-D-37,
IV-D-38, IV-D-41, IV-D-43, IV-D-44, IV-D-54, IV-D-55, IV-D-67,
IV-D-80, IV-D-95, IV-D-99, VI-B-02, VI-B-03, VI-B-04, VI-B-05,
VI-B-06) urged the EPA to justify the additional cost of
selecting control levels more stringent than the MACT floor
(IV-D-28, IV-D-54, IV-D-67, IV-D-80, VI-B-02, VI-B-03,
VI-B-04, VI-B-05, VI-B-06 only) or provide the required
funding to local governments. Two commenters (IV-D-96,
VI-B-02) stated that EPA's failure to make this justification
would represent a violation of the executive order. One
commenter (IV-D-99) contended that the EPA must establish MACT
at the MACT floor or provide the necessary funding to local
governments. Three commenters (IV-D-43, IV-D-67, IV-D-95)
recommended that the EPA adhere to the MACT floor to comply
with the administrative procedures required by Executive
Order 12875.
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Response: Executive Order 12875, "Enhancing the
Intergovernmental Partnership," which President Clinton signed
on October 28, 1993, is directed at reducing the imposition of
unfunded mandates upon State, local, and tribal governments.
The Order precludes the EPA to the extent feasible and
permitted by law from promulgating any regulation that is not
required by statute and that creates a mandate upon a State,
local, or tribal government, unless:
(1) Funds necessary to pay the direct costs
incurred by the State, local, or tribal government
in complying with the mandate are provided by the
Federal Government; or
(2) The Agency, prior to the formal promulgation of
regulations containing the proposed mandate,
provides to the Director of the Office of Management
and Budget a description of the extent of the
Agency's prior consultation with representatives of
affected State, local, and tribal governments, the
nature of their concerns, any written communications
submitted to the Agency by such units of government,
and the Agency's position supporting the need to
issue the regulation containing the mandate.
E.O. 12875, § 1(a) (Oct. 25, 1993). The EPA has reviewed the
requirements of Executive Order 12875, and disagrees with the
commenters who stated that the emission guidelines violate its
terms.
The emission guidelines promulgated today are the most
cost-effective and least burdensome alternative for regulating
existing MWC's that satisfy the statutory requirements of
sections 111 and 129 of the Act. Section 129(a)(2) of the
Clean Air Act requires that the guidelines for existing MWC's
reflect the maximum degree of reduction in emissions of the
air pollutants designated in section 129(a)(4), taking into
consideration the cost of achieving such emission reduction,
and any non-air-quality health and environmental impacts and
energy requirements that the Administrator determines are
achievable for a particular category of sources (this standard
is commonly referred to as "maximum achievable control
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technology, or "MACT"). Section 129 also provides that the
emission limitations in the guidelines for existing MWC's may
not be less stringent than the average emission limitations
achieved by the best performing 12 percent of units in the
category. This is referred to as the "MACT floor" for
existing MWC units. Emission control options less stringent
than the MACT floor can not be considered in developing
section 129 guidelines.
The guidelines for existing sources have been set at the
MACT level of control. For some pollutants, control levels
more stringent than the floor have been required and are
achieved at minimal costs. For large plants, the MACT
standards are at the floor for all pollutants except three:
dioxins/furans, Cd, and Hg. There is no unfunded mandate
associated with the MACT standards that are set at the
respective MACT floors because these levels are required by
statute.
There also is no unfunded mandate associated with the
final emission limits for dioxins/furans and Cd, even though
the guidelines for these pollutants are more stringent than
their respective MACT floors. This is because levels more
stringent than the floors can be achieved by requiring optimal
performance of the same acid gas/PM control systems that MWC
owners and operators need to meet the MACT floor levels (and
final emission guidelines) for SO2 and PM. Therefore, setting
the dioxin/furan and Cd emission limits at a lower emission
rate (more stringent) than the MACT floors does not result in
any additional control costs.
To achieve the Hg guidelines, additional control (i.e.,
carbon injection) may be required. Because of the toxicity
and bioaccumulation potential of Hg, the small incremental
cost of adding Hg control ($1.00 to $1.40/Mg of MSW combusted)
is reasonable. Further, a consideration of the factors
specified in section 129(a)(2) -- cost, emissions reductions,
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and non-air quality health and environmental factors) led the
Administrator to conclude that MACT for Hg control includes
carbon injection. The final Hg emission limit is a level that
is achievable by acid gas/PM control systems combined with
carbon injection.
The EPA notes that Federal funds are not available to pay
the nominal direct costs that State or local governments that
own MWC's may incur in order to comply with the mercury
emission guidelines promulgated today. (Since no tribal
governments own MWC's, no tribal governments are affected by
the emission guidelines.) However, prior to the formal
promulgation of these emission guidelines, the EPA satisfied
the requirements of section 1(a)(2) of Executive Order 12875.
The analysis for the guidelines promulgated today for
small MWC's is analogous. The final emission guidelines are
more stringent than the floor for six designated pollutants.
However, of the six emission limits that are more stringent
than their respective MACT floor emission levels, five are
limits that represent optimal performance of the acid gas/PM
control system and which can be achieved with no additional
control costs. The only limit that may require additional
control is the limit for Hg, which may require the addition of
carbon injection to achieve. After considering the same
factors as were considered above for existing MWC's at large
MWC plants, the Administrator concluded that MACT for Hg
control includes carbon injection. Thus, the final Hg MACT
emission limit for existing MWC's at small MWC plants are the
levels that are achievable by acid gas/PM control systems
combined with carbon injection.
Accordingly, the EPA has met the requirements of
Executive Order 12875 by (1) Promulgating standards that are
either statutorily required or, where more stringent than the
floor, are standards that can be achieved at a cost that is
reasonable in light of the environmental hazards posed; and
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(2) consulting with affected State and local officials to hear
any concerns they may have with the proposed emission
guidelines.
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