PROJECTED REVISED MACT LIMITS FOR
EXISTING HAZARDOUS WASTE INCINERATORS
Joseph W. Nixon and Gerald J. Drake
Compliance Strategies & Solutions, Inc.
Abstract Log ID: 1Nixon
ABSTRACT
The U.S. Court of Appeals in the District of Columbia vacated challenged portions of the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) rule on July 24, 2001. The Court ruled that EPA failed to follow the Clean Air Act (CAA) procedures for establishing MACT standards for emissions of hazardous air pollutants from hazardous waste burning cement kilns, lightweight aggregate kilns, and incinerators. As a result, the Court remanded the HWC MACT floors to EPA for further proceedings. Thus, EPA will have to adhere to the CAA procedures to establish revised MACT floors that reflect a reasonable estimate of the emissions achieved in practice by the best performing sources. This could very likely mean that the emission standards for HWC MACT regulated constituents will become more stringent (i.e., lower allowable emission rates).
This paper presents an evaluation of the emissions data for existing hazardous waste incinerators contained in the HWC Emissions Database utilizing the methodology Congress directed the EPA to follow when establishing the floor level emission limits for hazardous waste combustors. The projections presented in this paper provide an indication of a possible floor level for each of the emissions parameters for existing hazardous waste incinerators.
This paper presents a review of emissions data for the best performing 12 percent of the 109 existing hazardous waste incinerators included in EPA’s database of HWC trial burn and compliance test emissions measurements. The emission parameters to be addressed in this paper include the following:
· Dioxins/Furans;
· Particulate Matter;
· Mercury;
· Semivolatile Metals;
· Low Volatile Metals; and
· Hydrochloric Acid/Chlorine Gas.
Details regarding EPA’s HWC database are presented in the Final Technical Support Document for HWC MACT Standards; HWC Emissions Database Volume II.1 Although the database includes an abundance of information regarding each existing hazardous waste incinerator, this paper is limited to addressing the stack gas emissions and the associated air pollution control devices (APCD) used by these units. The stack gas emissions for particulate matter (PM), total chlorine (TCl), dioxin/furan toxic equivalents (D/F TEQ), mercury (Hg), semivolatile metals (SVM) including cadmium and lead, and low volatile metals (LVM) including arsenic, beryllium, and chromium have been evaluated to estimate the floor values for establishing the projected revised MACT emission standards for existing hazardous waste incinerators. Carbon monoxide (CO), hydrocarbons (HC), and destruction and removal efficiency (DRE) criteria are expected to remain unchanged, and are not included in this evaluation.
BACKGROUND
Section 112(d)(3) of the CAA, as amended by the Clean Air Act Amendments (CAAA) of 1990, directs the EPA to establish emissions standards for existing sources as follows:2
Emission standards promulgated under this subsection
for existing sources in a category or subcategory may be less stringent than
standards for new sources in the same category or subcategory but shall not be
less stringent, and may be more stringent than –
(A)
the average emission limitation achieved by the
best performing 12 percent of the existing sources (for which the Administrator
has emissions information), excluding those sources that have, within 18 months
before the emission standard is proposed or within 30 months before such
standard is promulgated, whichever is later, first achieved a level of emission
rate or emission reduction which complies, or would comply if the source is not
subject to such standard, with the lowest achievable emission rate (as defined
by section 7501 of this title) applicable to the source category and prevailing
at the time, in the category or subcategory for categories and subcategories
with 30 or more sources, or
(B) the average emission limitation achieved by the best performing 5 sources (for which the Administrator has or could reasonably obtain emissions information) in the category or subcategory for categories or subcategories with fewer than 30 sources.
To establish the emission standards required by the CAA, EPA assembled a database of sources and their emission levels recorded primarily during RCRA compliance tests representing worst case operating conditions. For existing sources, EPA used the database to identify the best performing 12 percent of sources, creating what is called the “MACT Pool.” EPA then identified the primary emission control technology (i.e., MACT control) used by sources in the MACT Pool with emission levels equivalent to, or lower than, the pool’s median. EPA next expanded the MACT Pool to include all sources using the MACT control (provided the control was well-designed and properly operated), and set the MACT floor at the highest emission level achieved by any source in the expanded pool.
On July 24, 2001, the U.S. Court of Appeals in the District of Columbia vacated challenged portions of the HWC MACT standards, and ruled that EPA failed to follow the CAA procedures in establishing the HWC MACT standards because the MACT floors were not set at the average emission levels achieved by the best performing 12 percent of sources.3 Rather, EPA set the MACT floors at the highest level achieved by sources using MACT controls. As a result of this ruling, EPA will have to adhere to the CAA procedures to establish revised MACT floors that reflect a reasonable estimate of the emissions achieved in practice by the best performing 12 percent of sources.
This paper provides a projection of the revised MACT standards for existing hazardous waste incinerators. These projections are based on the database in place at the time of the EPA’s original evaluation. EPA is now gathering additional information to add to the database for establishing the final standards.
The procedures used in the following sections to project the revised MACT limits for existing hazardous waste incinerators follow the CAA mandate to establish MACT limits by averaging the emissions from the best performing 12 percent of sources for categories with 30 or more sources. For the purposes of this paper, the universe of existing hazardous waste incinerators is assumed to be the source category from which the emissions of the best performing 12 percent of sources were averaged. Subcategorization of the universe of existing incinerators was not performed.
The best performing 12 percent of sources were selected based on EPA’s ranking of sources. For D/F and PM, where emissions are not strongly related to the feedrate of specific hazardous air pollutants (HAPs) in the hazardous waste, the EPA’s ranking of sources is based on the lowest test condition average stack gas emission concentrations. For the Hg, SVM, LVM, and TCl standards, where emissions are directly related to the feedrate of HAPs contained in the hazardous waste, EPA used an “Aggregate Feedrate” approach to rank the sources.4 According to EPA, the Aggregate Feedrate approach was used to rank each source based on the feedrate maximum theoretical emissions concentration (MTEC) for the chlorine and metal HAPs. The feedrate MTEC is determined as the theoretical emission concentration if all of the species fed to the device are assumed to partition directly to the stack.
For the chlorine and metal HAPs, the EPA used the feedrate MTEC values to rank each source. Once ranked according to the feedrate MTEC, the corresponding stack gas emission concentrations were used to establish the MACT floors. Therefore, the projected revised MACT floors were determined as the average stack gas emission concentration of the best performing 12 percent of sources that were ranked by the feedrate MTEC. The projected revised MACT floors for D/F and PM were determined by averaging the stack gas emission concentrations for the 12 percent of best performing sources.
In identifying the best performing 12 percent of sources, only conditions from different sources were selected to define the projected revised MACT standards. Any source that had more than one test condition in the best performing 12 percent of test conditions was used only once, and the next-in-line sources were selected to obtain the required number of different sources.
RESULTS
Using the universe of existing hazardous waste incinerators as a single
source category, the best performing 12 percent of sources (i.e., 13 out of 109
incinerators) were evaluated to project the revised MACT floors for each
parameter. The results of this
evaluation are presented in Table I. Tables II through VII summarize the
detailed evaluation of the best performing sources for each parameter. Table VIII provides a comparison of the
interim MACT standards to the projected revised MACT floors.5
Table I. Projected Revised MACT Floors for Existing Hazardous Waste
Incinerators
|
|
PM (gr/dscf) |
TCl (ppmv) |
Hg (µg/dscm) |
SVM (µg/dscm) |
LVM (µg/dscm) |
D/F TEQ (ng/dscm) |
|
Average |
0.0008 |
6.3 |
25.2 |
24.3 |
72.5 |
0.0076 |
|
Maximum |
0.0010 |
39.0 |
173.0 |
91.0 |
803.0 |
0.016 |
|
Minimum |
0.0002 |
0.0 |
1.0 |
2.0 |
1.0 |
0.001 |
|
Std. Dev. |
0.00035 |
10.5 |
46.5 |
26.5 |
219.8 |
0.0051 |
The data in this table is corrected to 7% oxygen.
Table II. Particulate
Matter Emissions
From Best Performing Existing Hazardous Waste
Incinerators
|
EPA Condition ID |
APCS Equipment |
PM Cond. Avg. (gr/dscf) |
|||
|
348C3 |
QC/AS/IWS |
0.0002 |
|||
|
337C1 |
WHB/DA/DI/FF |
0.0002 |
|||
|
325C8 |
SD/FF/WS/IWS |
0.0002 |
|||
|
354C1 |
QC/AS/VS/DM/IWS |
0.0010 |
|||
|
350C2 |
WHB/HE/FF |
0.0010 |
|||
|
209C2 |
WHB/FF/VQ/PT/DM |
0.0010 |
|||
|
327C3 |
SD/FF/WS/WESP |
0.0010 |
|||
|
603B1 |
QT/S/IWS |
0.0010 |
|||
|
612C1 |
SD/FF |
0.0010 |
|||
|
338C2 |
QC/FF/SS/C/HES/DM |
0.0010 |
|||
|
349C2 |
QC/FF/QC/PT |
0.0010 |
|||
|
222C5 |
WHB/SD/CI/ESP/Q/PBS |
0.0010 |
|||
|
341C2 |
DA/DI/FF/HEPA/CA |
0.0010 |
|||
|
|
|||||
|
Average |
Maximum |
Minimum |
Standard Deviation |
||
|
0.0008 |
0.0010 |
0.0002 |
0.00035 |
||
Table III. Total Chlorine Emissions
From Best Performing Existing Hazardous Waste
Incinerators
|
EPA Condition ID |
APCS Equipment |
TCl
Stack Emissions (ppmv) |
Cl MTEC (ug/dscm) |
|
613C2 |
WHB/Q/S/PBS |
0.3 |
1.0E+05 |
|
347C1 |
C/QT/VS/PBS/DM |
0.0 |
1.1E+05 |
|
711C2 |
C/WHB/VS/AS |
1.0 |
1.5E+05 |
|
504C1 |
VS/C |
5.0 |
1.5E+05 |
|
806C1 |
C/VS |
39.0 |
1.0E+06 |
|
701C2 |
VS/PT |
1.0 |
1.4E+06 |
|
480C3 |
QC/HS |
3.0 |
1.4E+06 |
|
700C2 |
SD/RJS/VS/WS |
4.0 |
1.7E+06 |
|
705C2 |
QT/VS/PT/WESP |
12.0 |
2.6E+06 |
|
805C1 |
QT/QS/VS/ES/PBS |
10.0 |
2.8E+06 |
|
609C1 |
SS/PT/VS/DM |
1.0 |
3.2E+06 |
|
495C2 |
WHB/ESP/Q/S |
1.0 |
3.3E+06 |
|
353C1 |
QC/VS/DM/WESP |
4.0 |
3.6E+06 |
|
|
|||
|
Average |
Maximum |
Minimum |
Standard Deviation |
|
6.3 |
39.0 |
0.0 |
10.5 |
Table IV. Mercury
Emissions
From Best Performing Existing Hazardous Waste
Incinerators
|
EPA Condition ID |
APCS Equipment |
Hg Stack Emissions (ug/dscm) |
Hg MTEC (ug/dscm) |
|
705C1 |
QT/VS/PT/WESP |
4.0 |
4.6E-02 |
|
603C8 |
QT/S/IWS |
5.0 |
7.2E-02 |
|
700C1 |
SD/RJS/VS/WS |
5.0 |
3.5E+00 |
|
824C1 |
QT/VS/PT/DM |
1.0 |
5.0E+00 |
|
341C1 |
DA/DI/FF/HEPA/CA |
1.0 |
5.3E+00 |
|
221C1 |
SS/PT/VS |
5.0 |
6.0E+00 |
|
488C1 |
SS/PT/VS/DM |
12.0 |
1.2E+01 |
|
490C1 |
SS/PBS |
28.0 |
1.8E+01 |
|
334C2 |
WS/WESP/PT |
4.0 |
3.0E+01 |
|
601C1 |
DS/FF/WS |
33.0 |
5.3E+01 |
|
337C1 |
WHB/DA/DI/FF |
173.0 |
6.1E+01 |
|
325C4 |
SD/FF/WS/IWS |
45.0 |
6.3E+01 |
|
340C2 |
WHB/ESP/WS |
12.0 |
1.1E+02 |
|
|
|||
|
Average |
Maximum |
Minimum |
Standard Deviation |
|
25.2 |
173.0 |
1.0 |
46.5 |
Table V. Semivolatile
Metal Emissions
From Best Performing Existing Hazardous Waste
Incinerators
|
EPA Condition ID |
APCS Equipment |
SVM Stack Emissions (ug/dscm) |
SVM MTEC (ug/dscm) |
|
348C4 |
QC/AS/IWS |
2.0 |
3.5E+01 |
|
341C1 |
DA/DI/FF/HEPA |
24.0 |
2.5E+02 |
|
603C8 |
QT/S/IWS |
3.0 |
3.5E+03 |
|
340C2 |
WHB/ESP |
13.0 |
3.7E+03 |
|
601C1 |
WHB/DS/FF/IWS |
36.0 |
4.1E+03 |
|
325C4 |
SD/FF/WS/IWS |
91.0 |
4.7E+03 |
|
354C1 |
QC/AS/VS/DM/IWS |
2.0 |
2.6E+04 |
|
337C1 |
WHB/DA/DI/FF |
62.0 |
4.2E+04 |
|
602C2 |
Q/S/C/DM/HEPA |
8.0 |
5.1E+04 |
|
209C1 |
WHB/FF/VQ/PT/DM |
11.0 |
1.3E+05 |
|
222B3 |
WHB/SD/CI/ESP/Q/PBS |
7.0 |
1.5E+05 |
|
327C2 |
SD/FF/WS/WESP |
22.0 |
2.1E+05 |
|
349C3 |
QC/FF/QC/PT |
35.0 |
5.3E+05 |
|
|
|||
|
Average |
Maximum |
Minimum |
Standard Deviation |
|
24.3 |
91.0 |
2.0 |
26.5 |
Table VI. Low Volatile
Metal Emissions
From Best Performing Existing Hazardous Waste
Incinerators
|
EPA Condition ID |
APCS Equipment |
LVM Stack Emissions (ug/dscm) |
LVM MTEC (ug/dscm) |
|
341C1 |
DA/DI/FF/HEPA/CA |
10.0 |
3.3E+02 |
|
348C4 |
QC/AS/IWS |
1.0 |
2.1E+03 |
|
325C5 |
SD/FF/WS/IWS |
46.0 |
2.4E+03 |
|
337C1 |
WHB/DA/DI/FF |
21.0 |
2.5E+03 |
|
601C2 |
WHB/DS/FF/WS |
14.0 |
7.2E+03 |
|
603C8 |
QT/S/IWS |
12.0 |
1.3E+04 |
|
354C1 |
QC/AS/VS/DM/IWS |
3.0 |
1.4E+04 |
|
340C2 |
WHB/ESP/IWS |
3.0 |
2.4E+04 |
|
222B3 |
WHB/SD/CI/ESP/Q/PBS |
2.0 |
3.0E+04 |
|
602C2 |
Q/S/C/DM/HEPA |
5.0 |
5.3E+04 |
|
209C1 |
WHB/FF/VQ/PT/DM |
12.0 |
8.3E+04 |
|
327C3 |
SD/FF/WS/WESP |
11.0 |
1.7E+05 |
|
331C3 |
Q/PT/IWS/DM |
803.0 |
1.4E+06 |
|
|
|||
|
Average |
Maximum |
Minimum |
Standard Deviation |
|
72.5 |
803.0 |
1.0 |
219.8 |
Note: The removal of the
803.0 ug/dscm value results in an average value of 11.7 ug/dscm.
Table VII. PCDD/PCDF Emissions
From Best Performing Existing Hazardous Waste Incinerators
|
EPA Condition ID |
APCS Equipment |
D/F TEQ (ng/dscm) |
||
|
1002C1 |
C/QT/VS/PBS/DM |
0.001 |
||
|
347C8 |
C/QT/VS/PBS/DM |
0.002 |
||
|
493C1 |
VS/PT |
0.002 |
||
|
609C1 |
WS |
0.004 |
||
|
477C5 |
QT/PT/VS/DM |
0.006 |
||
|
478C1 |
Q/VS/DM |
0.006 |
||
|
603C5 |
WQ/WS/IWS |
0.006 |
||
|
494C50 |
VS/PT |
0.007 |
||
|
354C2 |
QC/AS/VS/DM/IWS |
0.009 |
||
|
805C3 |
QT/QS/VS/ES/PBS |
0.010 |
||
|
480C1 |
QC/HS |
0.015 |
||
|
357C50 |
VS/IWS |
0.015 |
||
|
500C1 |
QC/VS/KOV/DM |
0.016 |
||
|
|
||||
|
Average |
Maximum |
Minimum |
Standard Deviation |
|
|
0.0076 |
0.016 |
0.001 |
0.0051 |
|
Table VIII. Comparison
of Interim MACT Standards for Existing Hazardous Waste Incinerators to
Projected Revised MACT Floors
|
|
PM |
TCl |
Hg |
SVM |
LVM |
D/F TEQ |
|
(gr/dscf) |
(ppmv) |
(ug/dscm) |
(ug/dscm) |
(ug/dscm) |
(ng/dscm) |
|
|
Interim MACT
Standards |
0.015 |
77 |
130 |
240 |
97 |
0.2 or 0.4 |
|
Projected MACT
Floor |
0.0008 |
6.3 |
25.2 |
24.3 |
72.5 |
0.0076 |
As noted in Table VI, the LVM emissions data for the best performing 12
percent of sources contains a value that is significantly higher than all the
other values (i.e., an order of magnitude higher). If that higher value were removed from the
data set, the LVM projected MACT floor in Table VIII would be 11.7 ug/dscm
instead of 72.5 ug/dscm.
AIR POLLUTION CONTROL SYSTEM (APCS) EQUIPMENT
The type of APCS equipment used by the evaluated sources varies
significantly with 44 different APCS configurations representing the best
performers. This section presents the
APCS equipment used by each of the best performing sources evaluated to project
the revised MACT floors for existing incinerators. Table IX provides a key to the abbreviations
for the various air pollution control equipment, and Table X presents the APCS
equipment used by the best performing existing hazardous waste incinerators and
classifies the types of APCS as either a dry, wet, or combined dry/wet system.
Table IX. Abbreviations for
APCS Equipment
|
Abbreviation |
Description |
|
Abbreviation |
Description |
|
AS |
Absorber |
|
KOV |
Knock Out Vessel |
|
C |
Cyclone |
|
PBS |
Packed Bed Scrubber |
|
CA |
Carbon Absorber |
|
PT |
Packed Tower |
|
CI |
Carbon Injection |
|
Q |
Quench |
|
DA |
Dilution Air |
|
QC |
Quench Column |
|
DI |
Dry Injection |
|
QS |
Quench Separator |
|
DM |
Demister |
|
QT |
Quench Tower |
|
DS |
Dry Scrubber |
|
RJS |
Reverse Jet Scrubber |
|
ES |
Entrainment Separator |
|
S |
Scrubber |
|
ESP |
Electrostatic Precipitator |
|
SD |
Spray Dryer |
|
FF |
Fabric Filter |
|
SS |
Spray Saturator |
|
HE |
Heat Exchanger |
|
VQ |
Venturi Quench |
|
HEPA |
High Efficiency Particulate Air |
|
VS |
Venturi Scrubber |
|
HES |
High Energy Scrubber |
|
WESP |
Wet Electrostatic Precipitator |
|
HS |
Hydrogen Chloride |
|
WHB |
Waste Heat Boiler |
|
|
Scrubber |
|
WQ |
Wet Quench |
|
IWS |
Ionizing Wet Scrubber |
|
WS |
Wet Scrubber |
Table X. APCS Equipment For The Best Performing
Existing Hazardous Waste
Incinerators
|
APCS Equipment |
PM |
TCl |
Hg |
SVM |
LVM |
D/F TEQ |
Type |
|
C/QT/VS/PBS/DM |
|
1 |
|
|
|
2 |
Wet |
|
C/VS |
|
1 |
|
|
|
|
Wet |
|
C/WHB/VS/AS |
|
1 |
|
|
|
|
Wet |
|
DA/DI/FF/HEPA |
|
|
|
1 |
|
|
Dry |
|
DA/DI/FF/HEPA/CA |
1 |
|
1 |
|
1 |
|
Dry |
|
DS/FF/WS |
|
|
1 |
|
|
|
Dry/Wet |
|
Q/PT/IWS/DM |
|
|
|
|
1 |
|
Wet |
|
Q/S/C/DM/HEPA |
|
|
|
1 |
1 |
|
Wet |
|
Q/VS/DM |
|
|
|
|
|
1 |
Wet |
|
QC/AS/IWS |
1 |
|
|
1 |
1 |
|
Wet |
|
QC/AS/VS/DM/IWS |
1 |
|
|
1 |
1 |
1 |
Wet |
|
QC/FF/QC/PT |
1 |
|
|
1 |
|
|
Dry/Wet |
|
QC/FF/SS/C/HES/DM |
1 |
|
|
|
|
|
Dry/Wet |
|
QC/HS |
|
1 |
|
|
|
1 |
Wet |
|
QC/VS/DM/WESP |
|
1 |
|
|
|
|
Wet |
|
QC/VS/KOV/DM |
|
|
|
|
|
1 |
Wet |
|
QT/PT/VS/DM |
|
|
|
|
|
1 |
Wet |
|
QT/QS/VS/ES/PBS |
|
1 |
|
|
|
1 |
Wet |
|
QT/S/IWS |
1 |
|
1 |
1 |
1 |
|
Wet |
|
QT/VS/PT/DM |
|
|
1 |
|
|
|
Wet |
|
QT/VS/PT/WESP |
|
1 |
1 |
|
|
|
Wet |
|
SD/FF |
1 |
|
|
|
|
|
Dry |
|
SD/FF/WS/IWS |
1 |
|
1 |
1 |
1 |
|
Dry/Wet |
|
SD/FF/WS/WESP |
1 |
|
|
1 |
1 |
|
Dry/Wet |
|
SD/RJS/VS/WS |
|
1 |
1 |
|
|
|
Dry/Wet |
|
SS/PBS |
|
|
1 |
|
|
|
Wet |
|
SS/PT/VS |
|
|
1 |
|
|
|
Wet |
|
SS/PT/VS/DM |
|
1 |
1 |
|
|
|
Wet |
|
VS/C |
|
1 |
|
|
|
|
Wet |
|
VS/IWS |
|
|
|
|
|
1 |
Wet |
|
VS/PT |
|
1 |
|
|
|
2 |
Wet |
|
WHB/DA/DI/FF |
1 |
|
1 |
1 |
1 |
|
Dry |
|
WHB/DS/FF/IWS |
|
|
|
1 |
1 |
|
Dry/Wet |
|
WHB/ESP |
|
|
|
1 |
|
|
Dry |
|
WHB/ESP/IWS |
|
|
|
|
1 |
|
Dry/Wet |
|
WHB/ESP/Q/S |
|
1 |
|
|
|
|
Dry/Wet |
|
WHB/ESP/WS |
|
|
1 |
|
|
|
Dry/Wet |
|
WHB/FF/VQ/PT/DM |
1 |
|
|
1 |
1 |
|
Dry/Wet |
|
WHB/HE/FF |
1 |
|
|
|
|
|
Dry |
|
WHB/Q/S/PBS |
|
1 |
|
|
|
|
Wet |
|
WHB/SD/CI/ESP/Q/PBS |
1 |
|
|
1 |
1 |
|
Dry/Wet |
|
WQ/WS/IWS |
|
|
|
|
|
1 |
Wet |
|
WS |
|
|
|
|
|
1 |
Wet |
|
WS/WESP/PT |
|
|
1 |
|
|
|
Wet |
Table XI summarizes the types of APCS used on the best performers for
each of the emission categories. Of the
44 different APCS configurations, 26 (59%) were wet systems, 6 (14%) were dry
systems, and 12 (27%) were a combination of a dry system followed by a wet
system. This table shows that 13 of 13
APCSs for the best performing D/F TEQ control were wet systems. For PM, SVM, and LVM, 6 of 13 best performers
were the combined dry and wet systems.
For Hg, 7 of 13 best performers were wet systems.
Table XI. Best Performing APCS
Type for Each Emission Category
|
APCS Type |
PM |
TCl |
Hg |
SVM |
LVM |
D/F TEQ |
Total |
|
Wet |
3 |
11 |
7 |
4 |
5 |
13 |
26 |
|
Dry |
4 |
0 |
2 |
3 |
2 |
0 |
6 |
|
Dry/Wet |
6 |
2 |
4 |
6 |
6 |
0 |
12 |
The APCS configurations were reviewed to determine which best performed
on multiple emission categories. Table
XII presents the results of this comparison.
This table shows that 25 of 44 APCS configurations (57%) were best
performers for only one emission category with 16 wet, 4 dry, and 5 dry/wet
systems. A total of 9 out of 44 APCS
configurations (20%) were best performers for 3 or 4 emission categories. No APCS configurations were best performers
on 5 or 6 of the emission categories.
One-third of the dry and combined dry/wet systems were best performers
on 3 or more emission categories, while 3 of 26 (12%) of the wet systems were
best performers on 3 or more emission categories.
Table XII. Number of Emission
Categories
For Which an APCS Was Best Performing
|
Number of Emission Categories |
APCS Configurations |
Type of APCS |
|||
|
Number |
Percent |
Wet |
Dry |
Dry/Wet |
|
|
1 |
25 |
57 |
16 |
4 |
5 |
|
2 |
10 |
23 |
7 |
0 |
3 |
|
3 |
5 |
11 |
1 |
1 |
3 |
|
4 |
4 |
9 |
2 |
1 |
1 |
|
5 |
0 |
0 |
0 |
0 |
0 |
|
6 |
0 |
0 |
0 |
0 |
0 |
|
Total |
44 |
100 |
26 |
6 |
12 |
Table XIII compares the best performers in each emission category to the
occurrence of best performers in the other emission categories. For example, the 13 best performers for PM
were also best performers for SVM and LVM nine times, for Hg 4 times, for D/F
TEQ once, and were never a best performer for TCl. In addition, 3 of the 13 PM best performers
were only best performers for PM and not for any other emission category. This table shows a strong correlation between
PM, SVM, and LVM emission control with corresponding negligible impact on the
control of TCl and D/F TEQ. There
appears to be a moderate correlation between the TCl and D/F TEQ emission
controls with a corresponding negligible impact on the control of PM, SVM, and
LVM. Eight of 13 (62%), 6 of 13 (46%),
and 6 of 13 (46%) of the D/F TEQ, TCl, and Hg best performers, respectively,
were only best performers for their specific category.
Table XIII. Comparison of the
Best Performers
Versus the Other Emission Categories
|
Best Performance Category |
Emission Categories |
|||||
|
PM |
TCl |
Hg |
SVM |
LVM |
D/F TEQ |
|
|
PM |
3 |
0 |
4 |
9 |
9 |
1 |
|
TCl |
0 |
6 |
3 |
0 |
0 |
4 |
|
Hg |
4 |
3 |
6 |
3 |
4 |
0 |
|
SVM |
9 |
0 |
3 |
2 |
10 |
1 |
|
LVM |
9 |
0 |
4 |
10 |
2 |
1 |
|
D/F TEQ |
1 |
4 |
0 |
1 |
1 |
8 |
CONCLUSIONS
For each parameter evaluated, the projected revised MACT floors for
existing hazardous waste incinerators are lower than the MACT standards
established by EPA in the interim standards HWC MACT rule. With the exception of low volatile metals,
the projected revised MACT floors are one to two orders of magnitude lower than
the interim MACT standards. For the LVM,
the removal of the highest value results in the projected revised MACT floor
for the best 12 performers to approach one order of magnitude lower than the
interim MACT standard. Consequently, if
EPA adheres to the ranking scheme previously used to satisfy the CAA
requirements, owners and operators of existing hazardous waste incinerators
should expect significantly lower MACT floors when the final replacement
standards are promulgated by June 2005.
Forty-four different APCS configurations represent the best performers,
where 26 (59%) were wet systems, 6 (14%) were dry systems, and 12 (27%) were
combined dry and wet systems. All of the
D/F TEQ, and most (11 of 13) of the TCl best performers, were wet systems. The combined dry and wet systems represented
the best performers (6 of 13) for PM, SVM, and LVM. For Hg, the wet systems represented the best
performers (7 of 13). For controlling
emissions from multiple categories, only 9 of 44 APCS configurations (20%) were
best performers for 3 or more emission categories. No APCS configuration was a best performer
for 5 or more categories. One-third of
the dry and combine dry/wet APCS configurations were best performers for 3 or
more categories verses 12% for the wet systems.
The various APCS configurations can be divided into 3 categories: those
that control PM, SVM, and LVM; those that control TCl; and those that control
D/F TEQ. Hg was controlled similarly by
the PM, SVM, LVM, and TCl systems. This
categorization is not surprising as the existing air pollution control systems
on incinerators were designed to control one or more specific parameters, and
most were not designed to address the current 6 MACT emission categories. Owing to the fact that none of the 44 best
performers were best performers in more than 4 of the emission categories, it
may not be technically or economically feasible for hazardous waste
incinerators to comply with the projected revised MACT floors.
This evaluation and its subsequent results are based on the data set
contained within the database that was used by EPA during the original
development of the standards. The EPA is
currently gathering additional information and data for the development of the
final MACT standards. In addition, the
results of this evaluation are based on all of the incinerators being grouped
into one category. Subcategorization of
the existing incinerators was not performed.
Due to the high degree of variability in air pollution controls among
existing incinerators, the apparent categorical performance of different APCS
configurations, and the significantly lower projected revised MACT floors, it
will be critical for industry to proactively support EPA’s efforts to develop
permanent replacement standards that are both technically and economically
feasible.
REFERENCES
1. Final Technical Support Document for HWC MACT Standard; HWC Emissions Database, Volume II, Main Report, July 1999.
2. 42 United States Code 7412(d)(3) as amended by the Clean Air Act Amendments of 1990.
3. Cement Kiln Recycling Coalition v. EPA, 255 F.3d 855, 872 (D.C. Cir. 2001).
4. Final Technical Support Document for HWC MACT Standards; Selection of MACT Standards and Technologies, Volume III, July 1999.
5. Federal Register; September 30, 1999; pp 52860, 52875, and 52891.