Projected MACT
Limits for Hazardous Waste Burning Boilers and Industrial Furnaces
Melissa L.
Douglas
Gerald J.
Drake
Compliance Strategies & Solutions, Inc.
1301 Regents Park Drive, Suite 203
Houston, Texas 77058
ABSTRACT
The United States Environmental Protection Agency
(EPA) issued a notice of data availability (NODA) titled “NESHAPS: Standards
for Hazardous Air Pollutants for Hazardous Waste Boilers and Industrial
Furnaces” in the Federal Register on June 27, 2000 (hereafter database)1.
Comments on the accuracy and completeness of this database were due to
the EPA by August 28, 2000. The EPA
intends to use this database as the basis for developing the maximum achievable
control technology (MACT) emission limits for hazardous waste burning boilers
and industrial furnaces (the Phase II Boiler MACT) not covered under the
previously promulgated hazardous waste combustor (HWC) MACT. A total of 115 sources were listed in the
June 2000 database.
This paper presents an evaluation of the database
utilizing the methodology Congress directed the EPA to follow when establishing
the floor level emission limits for sources.
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.
The floor level emission limits are calculated by
averaging the emissions of the best performing 12 percent of sources for
categories with 30 or more sources, or the best performing 5 sources when there
are fewer than 30 sources. The
projections presented in this paper provide an indication of a possible floor
level for each of the above parameters for the database as a whole, as well as
individually for the combustion categories identified under this NODA. The projected floor levels will also be
compared to the HWC MACT standards actually promulgated in the Federal Register
on September 30, 1999. The pertinent air
pollution control devices (APCD) used for these units will be presented.
INTRODUCTION
This
paper presents a review of the data included in the EPA’s Phase II HWC MACT
Data Base Report, dated June 2000. The
115 units included in this database include 83 boilers, 11 heaters, 15 halogen
acid furnaces (HAFs), 5 sulfuric acid recovery furnaces (SARFs), and one unit
whose type was not identified. The
unidentified source was not included in this evaluation. This data was
collected from formal regulatory compliance testing programs including
certification of compliance (CoC), trial burn, and/or risk burn testing. Multiple test conditions for the same source
were frequently included in the database.
The EPA requested that interested parties provide comments on this database
by August 28, 2000. Accordingly, 57
facilities provided specific comments on their individual units and 17
corporate offices provided company-wide comments. Approximately 1/3 of the facilities (41) did
not provide any comments on the database.
It
is important to note that the information included herein is based on the June
2000 database. Prior to evaluating this
data, a request was made to obtain an updated database based on the EPA’s
request for comments. This request was
made to Mr. H. Scott Rauenzahn who was identified as the EPA contact for this
database2. Mr. Rauenzahn
indicated that the database had been updated to include the new information but
that it was not available for distribution.
He added that there were no immediate plans to include the updated
database on the Internet. He also
indicated that the data was available in the docket and estimated that it would
take an individual approximately one month to extract the data from the various
commenters. He went on to state that the
additional data did not significantly impact the results from the June 2000 database.
Although
the database includes a plethora of information regarding each individual unit,
this paper is limited to addressing the stack gas emissions and the associated
APCDs in use for 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 the low volatile metals (LVM) including arsenic,
beryllium, and chromium have been evaluated to estimate the floor values for
establishing the Phase II Boiler MACT emission standards. Carbon monoxide (CO), hydrocarbons (HC), and
destruction and removal efficiency (DRE) criteria are expected to remain
unchanged and are not included in this evaluation.
The
Clean Air Act (CAA), as amended by the CAA of 1990, directs the EPA to
establish minimum emission standards for existing sources as follows3:
“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 or 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.”
APPROACH
Using
the CAA methodology, the projected MACT floor levels were derived using two
separate approaches. The first approach
used the entire database as a source category.
The second approach separated the sources into subcategories (i.e.,
boilers, HAFs, SARFs, and heaters). The
projected results from these approaches are then compared to the results
promulgated for incinerators, cement kilns, and light-weight aggregate kilns.
RESULTS
The
first approach reviewed the database as a whole, hence the 115 sources as a
single category. The 14 best performers
(top 12 percent) were evaluated for each parameter. Table 1 presents the
projected floor levels (average values) using the first approach by identifying
the top 14 performers for each parameter without regard for
sub-categorization. Table 1 also
includes the maximum, minimum, and standard deviation values for the top 14
performers. Each unit was included only once in the top 14 performers, even if
multiple test conditions for that unit would be identified as a top 14
performer. The best performing test
condition was included with the remaining conditions being ignored.
Table 1. Top 14 Performers (all
categories combined)4.
|
|
PM (gr/dscf) |
TCl (ppmv) |
Hg (µg/dscm) |
SVM (µg/dscm) |
LVM (µg/dscm) |
D/F TEQ (ng /dscm) |
|
Average |
0.00067 |
0.05 |
0.09 |
1.08 |
3.19 |
0.0025 |
|
Maximum |
0.00120 |
0.11 |
0.32 |
2.19 |
7.16 |
0.0043 |
|
Minimum |
0.00010 |
0.00 |
0.00 |
0.08 |
0.14 |
0.0000 |
|
Std. Dev. |
0.00036 |
0.038 |
0.084 |
0.771 |
2.252 |
0.00114 |
The
data in this table is corrected to 7% oxygen.
The
subcategories of the top 14 performers for each parameter are identified as
follows:
·
PM – 8 Boilers, 2 HAFs, 2 SARFs, and 2 Heaters
·
TCl – 12 Boilers, 1 HAF, and 1 SARF
·
Hg – 5 Boilers and 9 HAFs
·
SVM – 5 Boilers, 8 HAFs, and 1 SARF
·
LVM – 5 Boilers, 8 HAFs, and 1 SARF
·
D/F TEQ – 14 Boilers
Table
2 presents projected floor levels (average values) using the second approach by
identifying the top performers for each subcategory. Table 2 also includes the maximum, minimum,
and standard deviation values for the units evaluated. Because there were 83 boilers (more than 30)
in this subcategory, the top 12 percent of performers were evaluated (i.e., the
best 10 boilers). None of the other subcategories
had more than 30 sources. Therefore, the
top 5 sources in each of the remaining subcategories were evaluated.
Table 2. Top Performers
(subcategories)4.
|
Boilers |
||||||
|
|
PM (gr/dscf) |
TCl (ppmv) |
Hg (µg/dscm) |
SVM (µg/dscm) |
LVM (µg/dscm) |
D/F TEQ (ng/dscm) |
|
Average |
0.00080 |
0.03 |
0.63 |
4.07 |
6.52 |
0.0020 |
|
Maximum |
0.00133 |
0.07 |
1.57 |
10.61 |
10.06 |
0.0032 |
|
Minimum |
0.00010 |
0.01 |
0.00 |
0.42 |
2.91 |
0.0000 |
|
Std. Dev. |
0.00043 |
0.020 |
0.599 |
3.811 |
2.505 |
0.00091 |
|
HAFs |
||||||
|
|
PM (gr/dscf) |
TCl (ppmv) |
Hg µg/dscm) |
SVM (µg/dscm) |
LVM (µg/dscm) |
D/F TEQ (ng/dscm) |
|
Average |
0.00147 |
0.79 |
0.04 |
0.39 |
0.78 |
0.1572 |
|
Maximum |
0.00280 |
1.61 |
0.07 |
0.98 |
1.52 |
0.5090 |
|
Minimum |
0.00044 |
0.00 |
0.00 |
0.08 |
0.14 |
0.0205 |
|
Std. Dev. |
0.00096 |
0.637 |
0.024 |
0.373 |
0.500 |
0.20219 |
|
SARFs |
||||||
|
|
PM (gr/dscf) |
TCl (ppmv) |
Hg (µg/dscm) |
SVM (µg/dscm) |
LVM (µg/dscm) |
D/F TEQ (ng/dscm) |
|
Average |
0.00105 |
2.13 |
1.44 |
7.20 |
9.31 |
0.0336 |
|
Maximum |
0.00185 |
5.73 |
1.98 |
12.40 |
11.48 |
0.0462 |
|
Minimum |
0.00027 |
0.08 |
0.91 |
2.00 |
7.14 |
0.0209 |
|
Std. Dev |
0.00066 |
2.50 |
0.76 |
7.356 |
3.069 |
0.01788 |
|
Heaters |
||||||
|
|
PM (gr/dscf) |
TCl (ppmv) |
Hg (µg/dscm) |
SVM (µg/dscm) |
LVM (µg/dscm) |
D/F TEQ (ng/dscm) |
|
Average |
0.00248 |
35.92 |
N/A |
36.10 |
N/A |
N/A |
|
Maximum |
0.00490 |
N/A |
N/A |
N/A |
N/A |
N/A |
|
Minimum |
0.00097 |
N/A |
N/A |
N/A |
N/A |
N/A |
|
Std. Dev. |
0.00169 |
N/A |
N/A |
N/A |
N/A |
N/A |
N/A
– Not Available
The
data in this table is corrected to 7% oxygen.
The
data presented in Table 2 was obtained from the database sources for each
subcategory as follows:
·
Boilers – Represented by the top 12% (10 units) for each parameter.
·
HAFs – Represented by the top 5 sources for each parameter.
·
SARFs – Represented by all 5 sources for PM, 4 sources for TCl, and 2
sources for Hg, SVM, LVM, and D/F TEQ.
·
Heaters – Represented by the top 5 sources for PM, 1 source for TCl and
SVM, and no sources for Hg, LVM, or D/F TEQ.
Table
3 presents the data from all 115 Phase II Boiler MACT sources including
multiple data from a single source. This
data is presented to provide a median range of where these units are operating
today as a whole. Table 3 also includes
the maximum, minimum, and standard deviation values for this data set.
Table 3. All Phase II Sources and
All Conditions4.
|
|
PM |
TCl |
Hg |
SVM |
LVM |
D/F TEQ |
|
Average |
0.01690 |
38.20 |
1.45 |
34.83 |
63.25 |
0.3141 |
|
Maximum |
0.09950 |
916.76 |
12.07 |
526.46 |
900.17 |
6.7736 |
|
Minimum |
0.00010 |
0.00 |
0.00 |
0.08 |
0.14 |
0.0000 |
|
Std. Dev. |
0.01827 |
115.88 |
2.519 |
88.872 |
135.22 |
0.98923 |
The
data in this table is corrected to 7% oxygen.
Table
4 summarizes the information provided in the first three tables as well as the
promulgated HWC MACT (i.e., incinerators, cement kilns, and light-weight
aggregate kilns) values for each of these parameters for comparison purposes.
Table 4. Comparison of Phase II
Boiler MACT Projected Results And HWC MACT Promulgated Results4,5.
|
|
PM (gr/dscf) |
TCl (ppmv) |
Hg (µg/dscm) |
SVM (µg/dscm) |
LVM (µg/dscm) |
D/F TEQ (ng/dscm) |
|
Top 14 Single Category |
0.00067 |
0.05 |
0.09 |
1.08 |
3.19 |
0.0025 |
|
Boiler Subcategory |
0.00080 |
0.03 |
0.63 |
4.07 |
6.52 |
0.0020 |
|
HAFs Subcategory |
0.00147 |
0.79 |
0.04 |
0.39 |
0.78 |
0.1572 |
|
SARFs Subcategory |
0.00105 |
2.13 |
1.44 |
7.20 |
9.31 |
0.0336 |
|
Heaters Subcategory |
0.00248 |
35.92 |
N/A |
36.10 |
N/A |
N/A |
|
Complete Data Set |
0.01690 |
38.20 |
1.45 |
34.83 |
63.25 |
0.3141 |
|
Incinerators |
0.015 |
77 |
130 |
240 |
97 |
0.2 or 0.4a |
|
Cement Kilns |
b |
130 |
120 |
240 |
56 |
0.2 or 0.4a |
|
Light-Weight Aggregate
Kilns |
0.025 |
230 |
47 |
250 |
110 |
0.2 or 0.4a |
a0.4 ng TEQ/dscm allowed if the inlet temperature to the
initial PM control device is less than or equal to 400oF.
b0.15 kg/Mg dry feed and 20% opacity. If there is an alkali by-pass stack
associated with the kiln or in-line kiln raw mill, the combined PM emissions
from the kiln or in-line kiln raw mill and the alkali by-pass must be less than
the PM emissions standard.
The
data in this table is corrected to 7% oxygen.
APCD
The
type of APCD used by the evaluated units varies significantly. In fact, many of the units were not equipped
with any type of APCD. This section
presents the APCD used, or lack thereof, for each of the various scenarios
presented above. A key to the abbreviations
for the APCD equipment is provided in Table 5.
Table 5. Abbreviations
for APCD Equipment4.
|
Abbreviation |
Description |
|
3STGHCLABS |
3
Stage HCl Absorbers |
|
ABS |
Absorber |
|
CC |
Contact
Cooler |
|
CLWS |
Chlorine
Wet Scrubber |
|
CONV |
Converter |
|
CWS |
Caustic
Wet Scrubber |
|
DM |
Demister |
|
DQ |
Dry
Quench |
|
DT |
Drying
Tower |
|
ESP |
Electrostatic
Precipitator |
|
FF |
Fabric
Filter |
|
GC |
Gas
Cooler |
|
HCLABS |
HCl
Absorber |
|
HEPA |
High
Efficiency Particulate Air |
|
ME |
Mist
Eliminator |
|
MGCLREC |
Magnesium
Chlorine Recovery |
|
PBS |
Packed
Bed Scrubber |
|
RH |
Reheater |
|
Q |
Quench |
|
QT |
Quench
Tower |
|
S |
Scrubber |
|
SDA |
Spray
Dryer Absorber |
|
SD |
Spray
Dryer |
|
SEP |
Separator |
|
SO3ABS |
S03
Absorber |
|
SO3CON |
S03
Converter |
|
VE |
Ejector
Venturi |
|
VS |
Venturi
Scrubber |
|
WESP |
Wet
Electrostatic Precipitator |
|
WHB |
Waste
Heat Boiler |
|
WQ |
Wet
Quench |
|
WS |
Wet
Scrubber |
|
WS-WS |
2
Stage Absorber Wet Scrubbers |
The
first approach used the 115 sources as a single source category. The APCD used for the 14 best performers (top
12%) for each emission parameter are identified as follows:
Table 6. APCD For The Top 14
Performers (Best 12% of all sources)4.
|
APCD |
PM |
TCl |
Hg |
SVM |
LVM |
DF TEQ |
|
None |
9 |
10 |
2 |
2 |
3 |
9 |
|
WHB/QT/GC/WESP/SO3CON/WS-WS |
1 |
|
|
1 |
2 |
|
|
Q/HCLABS/WS |
1 |
1 |
|
1 |
1 |
|
|
WHB/QT/CC/WESP/DT/CONV/SO3ABS/ME |
1 |
|
|
|
|
|
|
QT/ABS/WS |
1 |
|
|
|
|
|
|
Q/HCLABS/CWS |
1 |
|
|
|
|
|
|
Unknown |
|
1 |
|
|
|
3 |
|
HCLABS/CWS |
|
1 |
|
|
|
|
|
WHB/QT/DT/SO3CON/ABS/WS/DM |
|
1 |
|
|
|
|
|
DQ/HCLABS/CLWS |
|
|
1 |
|
|
|
|
VS/WS |
|
|
1 |
1 |
|
|
|
WHB/HCLABS/WS |
|
|
2 |
2 |
1 |
|
|
WHB/Q/HCLABS/VE/CLWS |
|
|
1 |
1 |
1 |
|
|
WHB/VS/Q/HCLABS/VS/CLWS |
|
|
1 |
1 |
1 |
|
|
WHB/HCLABS/CWS |
|
|
1 |
1 |
1 |
|
|
WHB/Q/HCLABS/VS/WS |
|
|
1 |
|
1 |
|
|
WQ/3STGHCLABS/S/CWS |
|
|
1 |
1 |
|
|
|
ESP |
|
|
1 |
2 |
|
1 |
|
MGCLREC/VS/SEP/DM |
|
|
1 |
1 |
1 |
|
|
FF |
|
|
1 |
|
1 |
1 |
|
SD/FF/PBS/RH/HEPA |
|
|
|
|
1 |
|
|
DQ/HCLABS/VS/CLWS |
|
|
|
|
1 |
|
Tables
7, 8, 9, and 10 present the APCD types for the top performers in each
subcategory using the second approach.
Table 7 presents the top 12% of boilers.
Table 8 presents the top 5 sources for HAFs. Table 9 presents the top 5 sources for
SARFs. Table 10 presents the top 5
sources for heaters.
Table 7. APCD For Boilers (top 12%)4.
|
APCD |
PM |
TCl |
Hg |
SVM |
LVM |
DF TEQ |
|
None |
8 |
9 |
5 |
4 |
6 |
6 |
|
Q/HCLABS/CWS |
1 |
|
|
|
|
|
|
HCLABS/CWS |
1 |
1 |
|
|
|
|
|
VS/WS |
|
|
1 |
1 |
|
|
|
ESP |
|
|
1 |
3 |
1 |
1 |
|
FF |
|
|
1 |
1 |
2 |
|
|
SDA/ESP |
|
|
1 |
|
|
|
|
Q/WS |
|
|
1 |
|
|
|
|
SD/FF/PBS/RH/HEPA |
|
|
|
1 |
1 |
|
|
Unknown |
|
|
|
|
|
3 |
Table 8. APCD For HAFs (top 5
sources)4.
|
APCD |
PM |
TCl |
Hg |
SVM |
LVM |
DF TEQ |
|
Q/HCLABS/WS |
1 |
1 |
|
1 |
|
1 |
|
QT/ABS/WS |
1 |
|
|
|
|
1 |
|
WHB/Q/HCLABS/VS/WS |
1 |
|
|
|
1 |
1 |
|
WHB/QT/WS |
1 |
|
|
|
|
|
|
WHB/HCLABS/CWS |
1 |
|
1 |
1 |
1 |
|
|
WHB/Q/HCLABS/VE/CLWS |
|
1 |
1 |
|
1 |
|
|
WHB/VS/Q/HCLABS/VS/CLWS |
|
1 |
1 |
1 |
1 |
|
|
Q/HCLABS/CWS |
|
1 |
|
|
|
|
|
DQ/HCLABS/VS/CLWS |
|
1 |
1 |
|
|
|
|
WHB/HCLABS/WS |
|
|
1 |
1 |
1 |
|
|
MGCLREC/VS/SEP/DM |
|
|
|
1 |
|
1 |
|
WQ/3STGHCLABS/S/CWS |
|
|
|
|
|
1 |
Table 9. APCD For SARFs (top 5
sources)4.
|
APCD |
PM |
TCl |
Hg |
SVM |
LVM |
DF TEQ |
|
WESP |
2 |
1 |
|
|
|
|
|
WHB/QT/GC/WESP/SO3CON/WS-WS |
1 |
1 |
1 |
1 |
1 |
1 |
|
WHB/QT/CC/WESP/DT/CONV/SO3ABS/ME |
1 |
1 |
|
|
|
1 |
|
WHB/DT/QT/SO3CON/ABS/WS/DM |
1 |
1 |
1 |
1 |
1 |
|
Table 10. APCD For Heaters (top 5
sources)4.
|
APCD |
PM |
TCl |
Hg |
SVM |
LVM |
DF TEQ |
|
None |
5 |
1 |
|
1 |
|
|
CONCLUSIONS
The
results of the top performers from either a single category approach or a
subcategory approach indicate projected floor levels that are approximately 0.5
to 3 orders of magnitude less than the limits promulgated for incinerators, cement
kilns, and light-weight aggregate kilns.
One reason for this disparity could be that some of the test conditions
included in the database were not designed to
demonstrate worst-case operating conditions.
For example, during risk burn testing chlorine and metals are generally
not spiked. Using emissions data from
these conditions to establish the MACT limits will result in emission limits
much more stringent than evaluating conditions designed to set the metals and
chlorine emission limits for a unit.
Another possible reason could be the burning of clean fuels in units
that do not have APCDs. In this case,
the facilities burning low ash and chlorine streams could cause the projected
results to be lower.
More
than half of the affected facilities provided comments on the June 2000
database. However, Mr. Rauenzahn
indicated that the new data had little impact on the overall database
results. Hence, it is likely that the additional
information provided by the commentors did not eliminate the top performing
test conditions used in these projections.
It
is interesting to note that the data set that most closely approximates the
emission limits established for the HWC MACT are those that include all the
data from all sources and all test conditions as presented in Table 3. In this case, except for mercury and SVM, the
floor values would be essentially equivalent to the HWC MACT standards.
REFERENCES
1. Federal Register; June 27, 2000; pp 39581 – 39584.
2. Personal conversation with
Mr. H. Scott Rauenzahn, Work Assignment Manager for the June 2000 Phase II HWC MACT Data Base Report, US
Environmental Protection Agency, in January 2001.
3. 42 United States Code 7412(d)(3) as amended by the Clean Air Act of 1990.
4. EPA’s HWC MACT Page. http://www.epa.gov/hwcmact (accessed
January 2001).
5. Federal Register; September 30, 1999; pp 52860, 52875, and 52891.