United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/SR-92/065 May 1992
EPA Project Summary
Pilot-Scale Evaluation of the
Thermal Stability POHC
Incinerability Ranking
J.W. Lee, W.E. Whitworth, and L.R. Waterland
A series of pilot-scale incineration
tests was performed at the Environ-
mental Protection Agency's (EPA's) In-
cineration Research Facility to evalu-
ate the thermal-stability-based princi-
pal organic hazardous constituent
(POHC) incinerability ranking. In the
tests, mixtures of 12 POHCs with pre-
dicted incinerabilities spanning the
range of most- to least-difficult-to-in-
cinerate classes were combined with a
clay-based sorbent and batch-fed to the
facility's pilot-scale rotary kiln incin-
erator via a fiberpack drum ram feeder.
Five tests were completed. Kiln operat-
ing conditions were varied to include a
baseline operating condition, 3 modes
of attempted incineration failure, and a
worst-case combination of the 3 failure
modes.
Kiln exit POHC destruction removal
efficiencies (DREs) were in the 99.99%
range for the volatile POHCs during
the baseline, mixing failure (increased
charge mass), and matrix failure (de-
creased feed H/CI) tests. Semivoiatile
POHCs were not detected in the kiln
exit for these tests; corresponding
DREs were generally greater than
99.999%. The thermal failure (low kiln
temperature) and worst-case (combina-
tion of thermal, mixing, and matrix fail-
ure) tests resulted in substantially de-
creased kiln exit POHC DREs. These
ranged from 99% or less for Freon 113
to greater than 99.999% for the less-
stable-ranked POHCs. General agree-
ment between relative kiln exit POHC
ORE and predicted incinerability class
was observed for those two tests.
This Project Summary was developed
by EPA's Risk Reduction Engineering
Laboratory, Cincinnati, Ohio, to an-
nounce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
One of the primary functions of the
EPA's Incineration Research Facility (IRF)
is to conduct research activities for the
EPA's Office of Solid Waste (OSW) in
support of regulation development and
implementation. One major regulatory is-
sue of high priority during 1990 concerned
the evaluation of an incinerability ranking
system for POHCs. The system was de-
veloped over the past several years by
the University of Dayton Research Insti-
tute (UDRI) under contract to EPA's Risk
Reduction Engineering Laboratory (RREL).
The 1981 hazardous waste incinerator
regulations require that an incinerator un-
dergo a trial burn performance test in or-
der to become permitted to operate. This
trial burn is required to show that the
incinerator is capable of achieving the
mandated 99.99% POHC ORE. In trial
burn planning, the incinerator operator is
required to select POHCs using two crite-
ria: concentration in the waste and diffi-
culty to thermally destroy, or "incinerability."
The incinerability ranking included in the
1981 regulations was based on compound
heat of combustion.
The heat of combustion ranking has
several acknowledged deficiencies, how-
ever. Thus, EPA initiated studies to define
Printed on Recyclecj Paper
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or develop alternate, more suitable
inolnsrability ranking approaches. One
such approach Is the thermal-stability-
based POHC ranking, developed by UDRI.
This ranking Is based on the temperature
required to achieve 99% destruction at 2
sec residence time under oxygen-starved
conditions as measured in laboratory ex-
periments. As of early 1990, the funda-
mental basis supporting the ranking ap-
proach had been documented and suffi-
cient information to rank the organic haz-
ardous constituents had been collected.
Since it is based only on laboratory-scale
data, evaluation of the thermal stability
POHC inclnerability ranking under actual
Incineration conditions became a high-pri-
ority research need for 1990.
The test program described in the full
report was designed to develop the data
to evaluate the POHC incinerability rank-
Ing at the pilot scale. The specific objec-
tive of the test program was to measure
the ORE of a number of POHCs under
each of several modes of incinerator op-
eration, and compare relative POHC DREs
as a function of incineration conditions
and feed characteristics. The comparison
would facilitate a determination of how
relative POHC DREs compared with ex-
pectations based on the thermal stability
ranking.
In the tests, a mixture of 12 POHCs
with predicted incinerabilities spanning the
range from the most-difficult-to-incinerate
class to the least-difffcult-to-incinerate class
was tested. This "POHC soup" mixture
was combined with a clay-based sorbent
solid matrix and packaged into fiberpack
drums for incineration testing in the rotary
kiln Incineration system (RKS) at the IRF.
The drums containing the soup/clay mix-
ture were batch fed to the RKS via a
fiberpack drum ram feeder.
A series of five incineration tests was
performed during which incinerator oper-
ating conditions and test mixture composi-
tion were varied. Specific test program
variables were:
• Kiln temperature
• Feed batch charge mass
• Feed composition, specifically
H/CI ratio
One test Was performed under typical
operating conditions with a baseline mix-
ture composition. The other tests varied
the above in an attempt to simulate vari-
ous modes of incineration failure, where
Incineration failure is defined to exist when
POHC DREs are less than 99.99%. The
various modes of incineration failure at-
tempted were thermal failure, mixing fail-
ure, feed matrix effects, and a worst case
combination of these.
Test Program
Test Facility
The IRF's RKS was used for this test
program. A process schematic of the RKS
is shown in Figurel. The IRF RKS con-
sists of a primary combustion chamber, a
transition section, and a fired afterburner
chamber. After exiting the afterburner, flue
gas flows through a quench section fol-
lowed by a primary air pollution control
system (APCS). The primary APCS for
these tests consisted of a venturi scrub-
ber followed by a packed-column scrub-
ber. Downstream of the primary APCS, a
backup secondary APCS, comprised of a
demister, an activated-carbon adsorber,
and a high-efficiency particulate (HEPA)
filter, is in place.
Synthetic Waste Mixture
Twelve POHCs were selected for inclu-
sion in the synthetic waste mixture em-
ployed in the test program. The
incinerability ranking groups 333 POHCs
included into 7 stability classes from most
stable (class 1) to least stable (class 7).
UDRI recommended that 2 compounds
from each class be included in the test
mixture and provided a list of candidates
for selection. The selection of compounds
from this candidate list was guided by
sampling and analysis, compound com-
patibility, compound availability, and safety
considerations.
The compounds selected for the test
mixture are listed in Table 1. The table
also notes the composition of two test
mixtures containing the POHCs. Test mix-
ture 1 was the baseline test mixture. The
POHC concentrations in test mixture 2
represent adjustments to relative POHC
concentrations to yield a mixture with de-
creased H/CI ratio.
The mixtures incinerated in the test pro-
gram were prepared using commercially-
available pure chemicals and materials.
Test material formulation consisted of add-
ing weighed quantities (1.3 kg, 3 Ib total)
of the mixture of the 12 organic constitu-
ents to a weighed quantity (2.3 kg, 5 Ib) of
an absorbent clay. The clay/organic mix-
tures were packaged into 1.5-gal fiberpack
drums lined with polypropylene bags, the
mouths of which were closed with wire
ties.
Test Conditions
The variables for the test program were
the H/CI ratio in the synthetic waste feed,
kiln temperature, and synthetic waste feed
charge mass. Five tests, specified to be
conducted with various combinations of
these parameters, were selected to evalu-
ate the relative incinerability of the POHCs.
The target test matrix is shown in Table 2.
Test 1 represented a baseline, or normal,
set of incinerator operating conditions. Test
2 attempted thermal failure by decreasing
the kiln exit temperature to a target of
649°C (1200°F). To further promote ther-
mal failure, 0.9 kg (2 Ib) of water was
added to each waste feed charge for Test-
2. In Test 3, mixing failure was attempted
by doubling the drum charge mass from
3.6 to 7.3 kg (8 to 16 Ib). This doubled
charge mass was introduced at half the
baseline frequency, so as to maintain the
overall waste feedrate equal to that for
the other test conditions. Test 4 was de-
signed to investigate the effects of reduc-
ing the H/CI ratio (matrix failure) in the
waste feed. Test 5 combined the three
failure-promoting conditions to produce a
"worst-case" condition by operating with
the kiln exit temperature at a target of
649°C (1200°F), introducing the waste at
double the baseline charge mass, and by
using a low H/CI ratio waste mixture.
For all tests, the average kiln exit tem-
peratures were within 14°C (26°F) of the
respective target temperatures. However,
actual O2 levels in the kiln exit flue gas
were generally higher than the target con-
centrations. The higher O2 levels were
generally the result of higher than ex-
pected air in-leakage into the kiln cham-
ber.
Sampling and Analysis
Procedures
The scope of the sampling effort under-
taken during this test program is illus-
trated in Figure 2, in which the sampling
locations and the corresponding sample
collection methods are identified. Specifi-
cally, the sampling effort during each test
consisted of:
• Obtaining a sample of the POHC/clay
feed mixture by compositing the con-
tents of 3 waste fiberpack drums ran-
domly selected during the test
• Obtaining a sample of the scrubber
blowdown liquor composited from grab
samples taken at hourly intervals over
the test period
• Obtaining a sample of the kiln ash by
compositing three samples from the
ash collection bin at the end of the
test
• Continuously measuring O2, CO, CO2,
and unheated total unburned hydro-
carbon (TUHC) concentrations in the
flue gas at the kiln exit; Oz concentra-
tions at the afterburner exit; O_, NO,
unheated TUHC, and heated TUHC
concentrations at the scrubber exit;
-------
WetScrubb
' Mrd D
Quench V Scrubber Liqi
^Vi t RecirculaSc
Afterburner Lri j_
Air r
Natural
Gas, *
L/qU/d J^Mft"*"™ 1 f O//* hH— ~
Feed TT- 1 Feeder ^^
Transfer || |JrCI^B|//ner [p^^
C' 4 h C- r IWf l(|" 1 Ajr Venturi ]
®r> Rotary Natuial Scrubber
Kiln Gas, Liquid Scrubb
Feed Recirci
Rotary Kiln Modular Prim
Incinerator Pollution Contrc
Figure 1. Schematic of the IRF rotary kiln incineration system.
Table 1. Synthetic Waste Mixture Composition
Concentration (Wt %)
Mixture 1 Mixture 2
3r
p N^l 1
" l/'NIl
jor \ Atmosphere
" T f
Up Demister r\Stack
f-^fig) (IvTIs o J
^=f/D MjX[r*~w f*^l Devices Pollution Control
System
Stability
Component HighH/CI LowH/CI T,,(2f fC) Rank? Class
Benzene 8 4 1,150
Chlorobenzene 8 4 990
Tetrachloroethene 8 33 890
1,2,2-Trichloro- 8 4 780
1, 1 ,2-Trifluoroethane
(Freon 113)
Benzenethiol 8 4 725
Nitrobenzene 8 4 655
Hexachlorocyclohexane 10 5 645
(Lindane)
Hexachloroethane 10 25 585
1,1,1-Trichloroethane 10 5 545
p-Dimethylaminoazobenzene 10 5 ~400
(methyl yellow)
Nicotine 10 5 <320
N-nitroso-di-n-butyl amine 2 2 <320
H/CI (molar) 3.6 1.2
3 1
22 1
43 2
92 3
122 3
150/151 4
159 4
213 5
233 5
268 6
286 to 289 7
316 to 331 7
* Temperature required to achieve 99 % destruction in 2 sec.
" Incinerability rank in list range from most refractory (No. I) to most labile (No. 333).
-------
Ttbla 2. Target Test Conditions
Test
1
2
3
4
S
KilnH/CI
(molar)
22.8
22,8
22.8
15.7
10.3
Kiln exit
temperature
"CfF)
871 (1600)
649 (1200)
871 (1600)
871 (1600)
649 (1200)
Kiln
exit Of
(%)
10.4
12.6
10.4
10.4
13.2
Afterburner exit
temperature
°C(>F)
982 (1800)
982 (1800)
982(1800)
982 (1800)
982 (1800)
Afterburner
exitO*
(%)
9.0
9.1
9.0
9.2
9.2
Organic/clay
perfiberpack
kg(lb)
3.6 (8)
4.5 (10)>
3.6(8)
3.6 (8)
3.6 (8)
Feed regimen
drums/charge
1
1
2
' 1
2
Charge
hr
12
12
6
12
6
0.9 kg (2 Ib) water added perfiberpack.
Attar- Quench VenturVP
rlftjn -,-te ?"ef ». uuencn column
rjHI I ^ burner m Section *" „ vr1
1 1 Scrubber
III 1
123 4 5
aCkBd » Dnrnf-fir » Carb°" » HEPA *( ID \ »
| " Domlstor *" Bed *• .Filter \^FanJ |
e 7
Sample Location
Feeds and residuals Continuous monitors Flue gas
Samplhg POHC/
point Clay Kiln Scrubber CO2
Mixture ash blowdown O2 CO2
1 X
2 X
3 XX
4 X
5 X
S X
7 XX
Method 0010 Method 0030 Methods
Unheated Heated (semivolatile (volatile (Particulate
NOX TUHC TUHC organics) organics and HCI)
XXX X
XXX X X
XX XX
FIgunS. Sampling matrix.
-------
and O2, CO, CO2, and heated TUHC
concentrations in the stack
• Sampling flue gas at the kiln exit,
scrubber exit, and stack for the
semivolatile and volatile POHCs us-
ing Method 0010 and Method 0030,
respectively
The laboratory analysis procedures used
to characterize the samples collected over
the test program included:
• Analyzing the composite feed, kiln
ash, and scrubber blowdown samples
from each test for volatile and
semivolatile organic constituents
• Analyzing Method 0010 train samples
from each test for semivolatile organic
hazardous constituents
• Analyzing Method 0030 train samples
from each test for volatile organic haz-
ardous constituents
Semivolatile organic analyses were per-
formed by Method 8270. Solid samples,
including waste feed and kiln ash, and
Method 0010 samples were Soxhlet-ex-
tracted by Method 3540 in preparation for
analysis. Liquid samples were liquid-liquid
extracted by Method 3510. Method 0030
(VOST) sample analysis was by thermal
desorption purge and trap GC/MS (Method
5040) analysis with an ion trap-detector.
Test Results
The POHC measurements at the kiln
exit are the most relevant with respect to
evaluating the incinerability ranking in that
the incineration failure conditions tested
involved varying kiln operation. Thus, in-
cineration failures achieved would be most
evident and best measured at the kiln
exit.
Figures 3 through 7 show kiln exit POHC
DREs measured in bar chart form. The
POHCs are ordered along the horizontal
axis by their thermal stability index rank-
ing from predicted most-stable (benzene)
to least-stable (N-nitroso-di-n-butyl amine).
The vertical axis is the quantity [-log (1-
DRE/100)] for each POHC, which repre-
sents the "number of 9's" of POHC de-
struction. A value of 1 signifies 90% ORE,
a value of 2 signifies 99% ORE, and so
on. Each bar represents the measured
ORE for the corresponding POHC. Where
flue gas analysis indicated that the par-
ticular POHC was below its detection limit,
a stacked bar format is used to convey
this information. The height of the bottom
bar of the stack represents the ORE cal-
culated using the practical quantitation limit
(PQL). The combined stacked bar is ex-
tended to the top of the chart, as a visual
reminder that the POHC was not detected
and that the measured ORE was greater
than that computed using the PQL.
The POHC DREs illustrated in Figures
3 through 7 were calculated using pre-
pared synthetic waste feed formulation
data. Feed samples were analyzed for
each test, as noted above. However, ana-
lyzed POHC concentrations in feed
samples were substantially lower than the
concentrations corresponding to the POHC
quantities used to form the POHC mix-
tures. On average, only between 12 and
29% of the volatile organic constituents
and between 27 and 82% of the
semivolatile organic constituents in the pre-
pared mixtures could be accounted for in
the feed analyses. Fiberpack weights mea-
sured during the tests rule out mass evapo-
rative loss as the explanation for differ-
ences between prepared and analyzed
concentrations. One possible explanation
is that the organic liquid constituents were
so tightly adsorbed to the porous clay that
the sample preparation procedures asso-
ciated with Methods 8240 and 8270 analy-
ses could not quantitatively free the or-
ganic constituents for detection in the
analyses. All test program data support
this hypothesis and it is believed that what
was prepared was indeed fed. For this
reason, prepared-composition-based
DREs alone are presented. Nevertheless,
all conclusions regarding relative DREs
are also supported using analyzed feed
composition data.
Table 1 noted that benzenethiol was
selected as one of the class 3 POHCs in
the POHC mixture. However, while per-
forming tests to verify that stable synthetic
waste organic feed mixtures could be pre-
pared, it was discovered that benzenethiol
quite rapidly and completely reacts, in the
presence of the other organics and the
clay matrix, to form diphenyl disulfide, a
class 6 compound. As a result, diphenyl
disulfide, not benzenethiol, was actually
fed to the incinerator. Thus, the ORE for
diphenyl disulfide is shown in Figures 3
through 7 bar charts, and its bar location
corresponds to its class 6 incinerability
order.
No DREs for nicotine are shown in
Figures 3 through 7. Nicotine recoveries
from matrix spike Method 0010 samples
were generally poor. These poor recover-
ies prevented making accurate assess-
ments of the DREs for this compound and
it has been omitted from the figures.
The following discusses relative POHC
DREs measured for each test in turn.
Test 1—Baseline Incineration
Conditions
The incinerator operating conditions for
Test 1 represented baseline incineration
operation, which, from past experience
would result in acceptable POHC destruc-
tion. As shown in Figure 3, kiln exit DREs
were 99.99% or greater for all POHCs.
Benzene, chlorobenzene, tetrachloro-
ethene, Freon 113, and 1,1,1-trichloro-
ethane were quantitatively measured at
the kiln exit and their corresponding DREs
are shown by the single bars. The remain-
ing POHCs were not detected at the kiln
exit and their respective DREs were rep-
resented by the two-segment stacked bars,
the significance of which was discussed
above.
The high POHC DREs confirmed that
this baseline incinerator operating condi-
tion was indeed capable of satisfactorily
destroying even the predicted most diffi-
cult to incinerate POHC, benzene. A weak
correlation might exist between ORE and
the POHC incinerability ranking, in that,
except for 1,1,1-trichloroethane which had
a ORE of about 99.99%, DREs for POHCs
ranked in class 4 and above were higher
than the class 3 and below POHCs. It
bears emphasis, however, that the mea-
sured POHC DREs only varied by small
degree (from 99.994% to 99.9997+%).
This, coupled with the lack of gross incin-
eration failure to broaden the incinerability
response, could explain the inability to
establish a clear correlation between ORE
and the incinerability ranking index from
the baseline test data.
It is interesting to note that 1,1,1-
trichloroethane, a POHC ranked in class
5 and believed to be relatively easy to
incinerate, had a measured DRE substan-
tially lower than similarly ranked POHCs.
One possible explanation is that 1,1,1-
trichloroethane is a common product of
incomplete combustion (PIC), and can be
formed during the incineration process,
potentially from hexachloroethane, another
component of the POHC mixture.
Test 2—Thermal Failure
(Quenching)
Test 2 was intended to simulate a ther-
mal failure condition through incineration
quench. This was accomplished by lower-
ing the kiln temperature from nominally
871 °C (1600°F) to 649°C (1200°F) via 2
means. A measured amount of water con-
tained in a polyethylene bag was added
to each waste feed fiberpack drum and
the kiln was fired at very high air/fuel ratio.
These two actions in combination would
be expected to create conditions condu-
cive to the formation of cold POHC-con-
taining pockets of gas which would es-
cape the kiln prior to being destroyed.
Figure 4 presents the kiln-exit POHC
DREs for this test. The data clearly indi-
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1 2 3 4 4 S
Stability Class
I Denotes POHC Not Detected
Flywo3. Kiln exit POHC DREs for Test 1.
1123445
Stability Class
I ~l Denotes POHC Not Detected
Figure 4. Kiln exit POHC DREs for Test 2,
1234455667
Stability Class
Denotes POHC Not Detected
FlguroS. Kiln extt POHC DREs for Test 3.
cate that this test condition resulted in
significantly different POHC DREs com-
pared to the baseline test. A wide range
of POHC DREs was observed, from less
than 99% for Freon 113 to greater than
about 99.999% for diphenyl disulfide,
methyl yellow, and N-nitroso-di-n-butyl
amine. The low DREs for several POHCs
confirmed that incineration failure did oc-
cur during this test.
With the exception of a few anomalies
(discussed below), a general correlation
between DRE and incinerability ranking
seems apparent for this test. The observed
DREs for the class 3 to 7 POHCs ap-
peared to follow the incinerability ranking
predicted behavior. Some POHC-to-POHC
variability existed within this sub-group of
POHCs. Lindane exhibited a higher DRE
than the neighboring ranked POHCs.
A considerably more significant devia-
tion from incinerability ranking expectation
involved the DREs of the 4 most-stable
ranked POHCs within classes 1, 2 and 3.
The relative DREs measured for these
four POHCs were in an order opposite to
the ranking predictions. The relative ex-
tent of incineration failure for these 4
POHCs was not in accordance with ex-
pectations from the thermal stability rank-
ing.
Test 3—Mixing Failure
One of the modes by which POHCs
can escape an incinerator undestroyed
results from the lack of adequate mixing
between POHC and oxidizer. For Test 3,
the weight of each waste charge to the
kiln was doubled, while the hourly waste
feedrate was maintained at a level consis-
tent with the other four tests. The doubled
waste charge was thought to increase the
likelihood of creating oxygen-deficient
pockets of POHCs in the kiln chamber.
The expectation was that if the oxygen-
deficient conditions persisted through the
kiln, undestroyed POHCs could escape
the kiln chamber.
However, as the data in Figure 5 show,
no clear failure was apparent during this
test. All POHC DREs were greater than
99.99% and exhibited trends similar to
those observed for the baseline condition
test (Test 1). DREs for nitrobenzene and
the group of POHCs ranked easier to in-
cinerate were high. Within this group, only
1,1,1-trichloroethane was detected in the
kiln exit flue gas sample at a level above
its POL The other less-stable ranked
POHCs were not detected in the kiln exit
flue gas.
The four most difficult to incinerate
POHCs, benzene, chlorobenzene,
tetrachloroethene, and Freon 113 were
present in the kiln exit flue gas sample at
-------
1234455
Stability Class
Denotes POHC Not Detected
6 6
Figure 6. Kiln exit POHC DREs for Test 4.
1 234455
Stability Class
Denotes POHC Not Detected
6 6
Figure 7. Kiln exit POHC DREs for Test 5.
levels corresponding to between 99.99 and
99.999% ORE.
No correlation between POHC DREs
and POHC incinerability ranking was ap-
parent for this test. DREs for the volatile
POHCs (detected in the flue gas) were
comparable to the DREs associated with
the PQLs for the semivolatile POHCs (not
detected in the flue gas).
Tesf 4—Matrix Failure
This test (Test 4) attempted to cause
incineration failure by decreasing the H/CI
ratio in the organic feed to the kiln. The H/
Cl ratio in the feed waste for Test 4 was
1.2, as compared to a H/CI ratio of 3.6 for
the baseline Test 1.
The kiln exit POHC DREs for this test
are shown in Figure 6. These were uni-
formly high: all exceeded 99.99%. As in
Test 3, no correlation between POHC DRE
and incinerability ranking was apparent
because the POHC DREs were uniformally
high.
One possible explanation for the inabil-
ity to achieve POHC DRE failure in this
test is that the actual H/CI ratio in the kiln
environment as a whole was quite differ-
ent from that in the waste feed itself. This
was so because the auxiliary fuel for the
burner, in this case natural gas, was a
significant additional source of hydrogen.
If this source of hydrogen is included, the
H/CI ratio in the total kiln environment for
this test would be 15.7, which may be
considerably higher than the H/CI ratio
required to cause DRE failure.
Test 5 —Worst Case
Combination
This last test was conducted to present
the most challenging combination of the
mechanisms tested in terms of POHC de-
struction failure. The kiln was operated at
the reduced temperature of 640°C
(1184°F) to induce thermal failure; the
waste feed charge size was doubled to
promote mixing failure; and the chlorine
content in the feed waste was elevated to
promote matrix failure. It should be noted
that, in a departure from Test 2 proce-
dures, no water was added to the feed
waste fiber drums, because doing so would
introduce a quantity of hydrogen that might
nullify any potential elevated chlorine (ma-
trix failure) effect.
Figure 7 shows the POHC DREs for
this test condition. In this test, 8 of the
11 POHCs were detected in the kiln exit
flue gas. This was in contrast to only five
POHCs being found at concentrations
above their PQLs during baseline Test 1.
The 3 most easily predicted incinerated
POHCs, namely, diphenyl disulfide, methyl
yellow, and N-nitroso-di-n-butyl amine were
not found above their PQLs. Assuming
that these POHCs were present at their
respective PQLs would lead to computed
POHC DREs > 99.998% for these 3
POHCs. These DREs, being higher than
those measured for the remaining POHCs,
were consistent with their incinerability
ranking indices.
The DREs for the 8 quantifiable POHCs
ranged from over 99 to almost 99.999%,
calculated based on feed formulation data.
Lindane had the highest DRE at
99.9989%. Freon 113 and 1,1,1-
trichloroethane exhibited the lowest DRE
at about 99.8%. While no monotonic cor-
relation between POHC DREs and
incinerability ranking order existed for this
test, a weak relationship may have ex-
isted for the class 3 through class 7
POHCs. As observed in Test 1, 1,1,1-
trichloroethane exhibited a DRE signifi-
cantly below that of its neighboring ranked
POHCs.
It is interesting to note how well the
relative POHC DREs of this "worst-case"
test compared to those observed for Test-
2. Recall that Test 2 simulated only quench
failure. The relative DREs for these two
tests exhibited similar patterns although 2
differences could be noted. One differ-
ence is the absolute DRE levels, which
for this test were generally higher than
those observed for Test 2. The other dif-
ference relates to the DREs for benzene
•U.S. Government Printing Office: 1992— 648-080/60020
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and 1,1,1-triohloroethane. The DREs for
benzene and 1,1,1-lrichloroethane were
nearly 2 "nines" higher for Test 2 than for
Test 5.
Conclusions
Conclusions from the tests include the
following:
• The baseline operation condition re-
sulted in effective POHC destruction.
Kiln exit POHC DREs were in the
99.99% range for the volatile POHCs
In the test mixture. Semivolatile
POHCs were not detected in the kiln
exit flue gas; corresponding lower
bound DREs were generally greater
than 99.999%.
Neither the mixing failure nor matrix
failure attempts resulted in incinera-
tion failure. Kiln exit POHC DREs were
comparable to those measured in the
baseline test for all POHCs.
The thermal failure and worst-case
tests resulted in kiln POHC destruc-
tion failure. For both tests, kiln exit
POHC ORE ranged from 99% or less
for Freon 113 to greater than 99.999%
J. W. Lee, W.E. Whltworth, and L.R. Water/and are with Acurex Corporation,
Jefferson, AK 72079.
R.C. Thurnau Is the EPA Project Officer (see below).
The complete report, entitled "Pilot-Scale Evaluation of the Thermal Stability POHC
Inclnarability Ranking," (Order No. PB92-166 966/AS; Cost: $35.00, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
for the highest-ranked (least-stable)
POHCs.
• For the incineration failure tests, there
was general agreement between ob-
served relative kiln exit POHC ORE
and thermal stability incinerability rank-
ing expectations. However, two de-
viations occurred for both tests.
- The class 1 compounds (benzene
and chlorobenzene) and the class
2 compound (tetrachloroethene)
were less stable (had greater kiln
exit ORE) than the class 3 com-
pound Freon 113.
- 1,1,1-trichloroethane was appar-
ently more stable in the baseline
and worst-case tests than its class-
5 ranking would suggest, when
compared to the other class 5 and
the class 4 compounds; production
of 1,1,1-trichloroethane as a PIC
could account for this observation.
The full report was submitted in
fulfillment of Contract 68-C9-0038 by
Acurex Corporation under the sponsor-
ship of the U.S. Environmental Protection
Agency.
United States
Environmental Protection
Agency
Center for Environmental
Research Information
Cincinnati, OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT NO. G-35
Official Business
Penalty for Private Use $300
EPA/600/SR-92/065
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