United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati OH 45268
&EPA
Research and Development
EPA/600/SR-92/068 Sept. 1992
Project Summary
Pilot-Scale Incineration of
PCB-Contaminated
Sediments from the New Bedford
Harbor Hot Spot Superfund Site
W. E. Whitworth and L. R. Waterland
A detailed test program was per-
formed at the U.S. Environmental Pro-
tection Agency's (EPA's) Incineration
Research Facility (IRF) to define the
incineration characteristics of contami-
nated marine sediments from the Hot
Spot in New Bedford Harbor, a
Superfund site near New Bedford, MA.
The sediments at this site are contami-
nated with PCB concentrations of 4,000
to over 200,000 mg/kg, as well as with
trace metals, chiefly cadmium, chro-
mium, copper, and lead, at concentra-
tions up to several hundred mg/kg. The
test program was designed to evaluate
the effects of incineration operating
conditions on the composition of the
discharge streams.
Three incineration tests were per-
formed using native sediments spiked
with pure PCB Askarel transformer
fluid. The third test also included a
period of operation with native
(unspiked) sediment alone. Spiking was
performed to increase the sediment
PCB content from nominally 6,000 to
nominally 46,000 mg/kg, a level that
allowed an unambiguous determination
of whether a regulatory level PCB de-
struction and removal efficiency (ORE)
of 99.9999% could be achieved For the
three spiked sediment tests, plans were
to vary kiln exit gas temperature from
816 to 982 °C (1,500 to 1,800 °F). Aver-
age test temperatures achieved were
824°C and 984 °C (1,516°C and 1,803
°F).
Test results show that greater than
99.9999% PCB ORE (100 • [1- flue gas
emission rate/feedrate]) was achieved
at both kiln temperatures with the af-
terburner operated at 1,208°C (2,206°F).
However, with a kiln solids residence
time of 0.5 hr, the treated sediments
(kiln ash) were still PCB-contaminated.
In tests with the PCB-spiked sediment
feed, incinerated without dewatering,
kiln ash contained 128 to 245 mg/kg of
PCBs. The PCBs in the kiln ash dis-
charge accounted for between 0.08%
and 0.14% of the PCBs fed, regardless
of kiln temperature. For a native
(unspiked) sediment feed incinerated
without dewatering, the kiln ash con-
tained 100 mg/kg of PCBs, which ac-
counted for 0.44% of the PCBs intro-
duced in the sediment feed. The wet
scrubber system discharge flue gas
contained low levels of polychlorinated
dibenzo-p-dioxins (PCDDs) and higher
levels of dibenzofurans (PCDFs), chiefly
total tetra-CDF (TCDF), penta-CDF
(PeCDF), and hexa-CDF (HxCDF). The
2,3,7,8-tetra-CDD (2,3,7,8-TCDD) toxic-
ity equivalent emissions were in the
nominal 0.05 to 0.10 ng/dscm range.
Of the contaminant trace metals,
chromium and copper were relatively
nonvolatile. The kiln ash discharge ac-
counted for nominally 80% to 90% of
the discharged amount of these met-
als. These fractions were not affected
by kiln temperature in the range tested.
Cadmium and lead exhibited relatively
volatile behavior, and increasingly so
at the higher kiln temperature. At low
kiln temperature the kiln ash discharge
accounted for 53% of the lead and 61%
of the cadmium discharged. At higher
kiln temperature these fractions de-
creased to the nominal 10% to 20%
range for cadmium and the 20% range
for lead. Scrubber exit flue gas frac-
tions (cadmium and lead) and scrubber
liquor fractions (cadmium) increased
accordingly. Neither treated sediments
nor the scrubber liquor were toxicity
characteristic (TC) hazardous wastes
based on their cadmium, chromium, or
lead concentrations. However, the lead
content of scrubber liquor toxicity char-
acteristic leaching procedure (TCLP)
leachate was near the TC regulatory
level. This suggests that the scrubber
Printed on Recycled Paper
-------
liquor discharge from a wet scrubber
could be a TC hazardous waste In the
Incineration of hlgher-than-tested lead-
containing sediments, or under ex-
tended scrubber operation at minimum
blowdown.
Test results suggest that Incinera-
tion would be an effective treatment
option for the she sediments. However,
sediment dewaterlng before Incinera-
tion, and/or incinerating at longer kiln
solids residence times might be re-
quired to yield a treated sediment not
contaminated by PCBs. If a wet scrub-
bar were used for particulate and acid
gas control, the scrubber blowdown
discharge might require further treat-
ment to stabilize teachable lead levels.
In addition, lead levels In flue gas emis-
sions from a wet scrubber air pollution
control system (ARCS) might be of con-
cern.
This Project Summary was devel-
oped by EPA's Risk Reduction Engi-
neering Laboratory, Cincinnati, OH, to
announce key findings of the research
project that Is fully documented In a
separata report of the same title (see
Project Report ordering Information at
back),
Introduction
EPA Region 1 Is conducting the reme-
dial design (RD) for the remediation of a
Superfund site located in New Bedford
Harbor near New Bedford, MA. According
to the record of decision (ROD) document
of 1990, the EPA has Identified approxi-
mately 10,000 yd3 of contaminated sedi-
ment in a 5-acre area of the harbor. This
area has been Identified as the Hot Spot
Operable Unit, and incineration of the
dredged sediment has been selected as
the treatment option. EPA Region 1 re-
quested that test burns be conducted at
EPA's IRF to support the RD for this
Superfund site.
The primary objective of this test pro-
gram was to obtain data to support the RD
plans and specifications. Therefore, the
test conditions were designed to evaluate
the effectiveness of varying incinerator op-
erating conditions in the destruction of
PCBs and other pollutants. Specifically,
thetest prog ram attempted to answerthese
questions:
• Can incineration effectively destroy
PCBs to the required regulatory level
ORE of 99.9999% In the flue gas
emission?
• What is the distribution of the con-
taminant trace metals in the discharge
streams during incineration of the sedi-
ment?
• What are the effects of incineration
excess air and temperature on or-
ganic constituent destruction and met-
als distributions, including the leach-
ability of the metals from the kiln ash?
• What is the effectiveness of the air
pollution control system (APCS), with
design and operating characterization
similar to those of the IRF venturi/
packed-column scrubber, in collect-
ing particulate and trace metals?
• Can the treated sediment (i.e., kiln
ash) from the incinerator be disposed
of as nonhazardous solid waste?
The test program consisted of a set of
three incineration tests in the rotary kiln
incineration system (RKS) at the IRF. These
tests were aimed at evaluating PCB de-
struction and the fate of contaminant trace
metals in the sediment as functions of kiln
temperature and kiln excess air level.
Test Program
Test Facility
A process schematic of the RKS is
shown in Figure 1. The IRF RKS consists
of a primary combustion chamber, a transi-
tion section, and a fired afterburner cham-
ber. After exiting the afterburner, flue gas
flows through a quench section followed
by a primary APCS. The primary APCS for
these tests consisted of a venturi scrubber
followed by a packed-column scrubber.
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.
Test Waste Description
Eight 30-gal drums of sediments were
dredged from the Hot Spot area of New
Bedford Harbor for these tests. A charac-
terization sample representing each drum
was shipped to the IRF for pretest analy-
ses. These samples were subjected to
proximate, PCB, and hazardous constitu-
ent trace metals analyses. The results of
these analyses showed that the average
total PCB concentration of the eight drums
was 5,300 mg/kg as received. The level
required in an RKS feed to be able to just
establish 99.9999% ORE at a typical RKS
feedrate of 68 kg/hr (150 Ib/hr) is 5,100
mg/kg, just below the average dredged
drum characterization sample level. Con-
sequently, it was decided to spike the test
sediment to higher PCB concentrations to
provide a margin in the ability to establish
99.9999% ORE. The material used to spike
the sediments was an Askarel transformer
fluid comprised of roughly 75% Aroclor
1242 and 25% Aroclor 1254. Resulting
spiked feed levels were 3.48% Aroclor 1242
and 1.11% Aroclor 1254.
For the test program, all eight drums of
sediment were shipped to the IRF, where
they were combined to form one test feed
material. Before testing, the combined sedi-
ments were repackaged into l.5-gal
fiberpack containers for feeding to the RKS
via the ram feeder system. The PCB spike
was added to the sediments during this
packaging. In addition to spiked sediments,
a number of fiberpack drums were pre-
pared without the PCB spike for testing
using only the native sediment.
Single-stage Ionizing
Wet Scrubber
Transfer
Duct
Ash-
Bin
Scrubber Liquor
Recirculation
Afterburner
Air
Natural
Gas,
Liquid
Feed
Atmosphere
Stack
-------
Test Conditions
The test series was designed to evalu-
ate the effects of incinerator operating con-
ditions on PCB destruction and trace metal
distributions in the incinerator discharge
streams. The operating parameters to be
varied were kiln exit gas temperature and
kiln excess air (exit flue gas O2) Three
tests were to cover the range of target kiln
exit flue gas temperatures of 816 and 982
°C (1,500 and 1,800 °F) and target kiln exit
O2 levels of 6% to 10%. For all tests, the
operating conditions noted in Table 1 were
to be held at the nominal values noted in
the table.
Table 2 summarizes the actual incin-
erator exit temperatures and flue gas lev-
els, including their ranges and averages
for each test during flue gas sampling.
These are compared with the respective
target conditions. During Test 3, unspiked
native sediment was fed to the kiln for a
period of time to collect kiln ash associated
with native sediment feed only. Test 3a
represents the period of native sediment
feed; Test 3b represents the period of
spiked sediment feed for the third test.
For all tests, the average kiln exit gas
temperature was within 8°C (16°F) of the
respective target temperature. The actual
O2 levels at the kiln exit were generally
higher than the target concentrations. The
higher O2 levels experienced resulted from
higher than expected air inleakage into the
kiln chamber because of the inability to
tightly secure a rotating kiln seal. The mini-
mum O2 achievable was 9% at the kiln exit.
The maximum O2 tested was 11.2%. As a
practical matter, these two levels present
comparable combustion environments.
Consequently, it was not possible to test
kiln excess air as a variable.
Table 1. Incinerator System Operating Conditions Held Constant
Operating Condition Value
Kiln solids residence time
Total sediment feedrate
Scrubber blowdown rate
Venturi liquor flowrate
Venturi pressure drop
Packed tower liquor flowrate
Scrubber liquor temperature
0.5 hr
68.2 kg/hr (150 Ib/hr)
0 Umin (0 gpm) or minimum operable
76 L/min (20 gpm)
6.2 kPa (25 in WC)
115 Umin (30 gpm)
43PC (12CPF)
Sampling and Analysis
Procedures
The scope of the sampling effort under-
taken during this test program is illustrated
in Figure 2, in which the sampling locations
are identified. Specifically, the sampling
effort during each test consisted of:
• Collecting samples of the sediment
feed from each drum received, as
well as a composite sample from the
mixing container in which all sedi-
ments received were blended before
the sediments were packaged into
feed fiberpacks.
• Collecting a composite sample of the
kiln ash.
• Collecting a composite sample of the
scrubber liquor.
• Continuously measuring O2 levels in
the kiln exit and afterburner exit flue
gases; O2, CO, CO2, NO and total
unburned hydrocarbon (TUHC) levels
at the venturi/packed-column scrub-
ber exit; and O2,
in the stack.
CO, and CO, levels
• Sampling flue gas at the scrubber
system exit for PAHs and PCBs.
• Sampling flue gas at the scrubber
system exit for PCDDs and PCDFs.
• Sampling flue gas at the scrubber
system exit for volatile organics.
• Sampling flue gas upstream of the
scrubber system for particle size dis-
tribution.
• Sampling flue gas upstream and
downstream of the scrubber system
for particulate and trace metals using
a variation of EPA Method 5 modified
for multiple metals capture.
• Sampling downstream of the scrub-
ber system and at the stack down-
stream of the secondary APCS for
particulate and HCI using Method 5
to comply with permit requirements.
An aliquot of the composited sediment
feed and each test's kiln ash was sub-
jected to the TCLP leaching procedure
and analyzed for cadmium, chromium, cop-
per, and lead. Waste feed samples, kiln
ash samples, and scrubber liquor samples
were analyzed separately for PCBs, PAHs,
Table 2. Actual Versus Target Operating Conditions for the New Bedford Harbor Tests
Temperature, °C fF)
Flue gas O2, %
Test
1
2
3a
3b
Date
3/15/91
3/19/91
3/21/91
3/21/91
Target
816(1,500)
982 (1,800)
982 (1,800)
982 (1,800)
Minimum
755(1,391)
945(1,733)
939(1,723)
968(1,775)
Maximum
Kiln exit
907(1,665)
1,022 (1,871)
1,010 (1,850)
999 (1,831)
Average
824 (1,516)
984 (1,803)
981 (1,797)
985 (1,805)
Target
6
6
10
10
Range
5.8 to 13.9
6.6 to 12.0
7.2 to 11.5
7.0 to 11.4
Average
11.2
9.0
9.3
10.0
1
2
3a
3b
3/15/91
3/19/91
3/21/91
3/21/91
1,204 (2,200)
1,204 (2,200)
1,204 (2,200)
1,204 (2,200)
1,195(2,183)
1,201 (2,194)
1,194(2,181)
1,198 (2,188)
Afterburner exit
1,221 (2,229)
1,213 (2,216)
1,226 (2,239)
1,214(2,217)
1,208 (2,206)
1,208 (2,206)
1,208 (2,206)
1,208 (2,206)
7
7
7
7
3.2 to 8.2
3.6 to 7.4
2.9 to 7.6
4.3 to 8.0
6.4
6.0
6.4
7.0
-------
T
Kiln
\
fc-
After-
burner
^
Quench
Section
w
Venturi/PacKea
Column
Scrubber
1
te~
Demister
^
Carbon
Bed
fr.
HEPA
Filter
5 6
Venturi/ Continuous Method Method Method
Sam- Sediment Kin Packed-Column Flue Gas 0010 0010 0030
pKng Feed Ash Scrubber Liquor Monitoring (PCBsand (PCDDs/ (Volatile
Point (Composite) (Composite (Composite) (CEMs) PAHs) OCDFs) Organics)
Particle Size
Distribution
(Cascade
Method Method
5 (Par- 5 (Par-
ticulate, ticulate,
Impactor) Trace Metals) HCI)
1
2
3
4
5
6
7
X
X
X
X
X
X
X
X
X
X
X
Figure 2. Sampling matrix.
and cadmium, chromium, copper, and lead.
The composite sediment feed sample was
ateo subjected to proximate (moisture, ash
content, and heat content) analysis and
ultimate (C, H, O, N, S, Cl) analysis.
Test Results
The results of the test program are
discussed in the subsections that follow.
Test results are grouped by analyte class.
Proximate and Ultimate
Analysis Results
The proximate and ultimate analysis
results for the composite sediment sample
analyzed are presented in Table 3. The
high moisture content of the test sedi-
ments Is consistent with their marine ori-
gin. Table 4 summarizes the cumulative
sediment weight fed for each test and the
total amount of kiln ash collected. As indi-
cated in the table, between 25% and 30%
of the sediment weight fed for a given test
was collected as kiln ash. This fraction
agrees quite well with the ash content of
the sediment obtained by proximate analy-
sis shown in Table 3.
PCB, Semivolatile and Volatile
Organic, and Dioxin/Furan
Analysis Results
Table 5 summarizes the PCB contents
of each incineration test sample. As noted
In the table, the spiked sediment feed con-
tained 3.48% Aroclor 1242 and 1.11%
Arocior 1254. The kiln ash resulting from
the incineration of the sediments (both
spiked and native), without dewatering, had
substantially reduced, though still signifi-
cant, PCB contents. The kiln ash for the
spiked wet sediment feeds contained be-
tween 96 and 177 mg/kg of Aroclor 1242,
and between 32 and 84 mg/kg of Aroclor
1254. Interestingly, within the range of the
variability of the data, the higher kiln tem-
perature tested for Tests 2 and 3 did not
result In significantly lower kiln ash PCB
concentrations than the lowertemperature
tested in Test 1. The kiln ash resulting from
native sediment feed incinerated without
watering also contained significant PCB
levels, 57 mg/kg Aroclor 1242 and 44 mg/
kg Aroclor 1254.
No scrubber liquor sample contained
detectable PCB at practical quantitation
Table 3. Proximate and Ultimate Analysis Re-
sults for the Composite Sediment
Feed Sample
Proximate Analyses
Moisture, % 63.9
Ash. % 28.5
Volatile matter, % 5.9
Fixed carbon, % 1.4
Higher heating value, kJ/kg 2,200
(Btu/lb (948)
Ultimate Analysis, %
C 11.1
H 1.2
N 0.4
S 0.6
Cl 0.9
limits (PQLs) of 1 ug/L for Aroclor 1242
and 0.3 ug/L for Aroclor 1254. The scrub-
ber exit flue gas contained low, though
measurable, levels of both PCB formula-
tions in Tests 1 and 2.
Table 6 summarizes the degree of PCB
decontamination achieved in each test, in
terms of the fraction of the amount of PCB
introduced in the incineratorfeed accounted
for by the resulting kiln ash. As shown in
the table, about 0.1% of the Aroclor 1242
and about 0.1% to 0.2% of the Aroclor
1254 fed in spiked sediments was ac-
counted for in the kiln ash produced. The
remaining 99.8% to 99.9% was removed
and largely destroyed, as discussed be-
low. Higher fractions of feed PCBs were
present in the kiln ash from the native
sediment test: 0.3% for Aroclor 1242 and
0.9% for Aroclor 1254.
The data shown in Tables 5 and 6
confirm that incineration under the condi-
tions tested was not sufficient to com-
pletely decontaminate the sediments. The
incineration temperatures tested, 820 to
980 °C (1,500 to 1,800 °F), were typical of
those that have resulted in successful de-
contamination, as was the kiln solids resi-
dence time (0.5 hr). The New Bedford
Harbor marine sediments, however, con-
tained substantial moisture; the composite
sediments tested were 64% moisture. Evi-
dently, with such high moisture content,
solids bed temperatures were not raised to
levels needed for more complete PCB de-
struction in the residence time available.
Longer solids residence times, 1 hr in the
IRF's experience, would have likely allowed
more complete PCB decontamination. Fur-
-------
Table 4. Sediment Feed and Ash Collected
Ash Collected
1
2
3a
3b
Test
(3/15/91)
(3/19/91)
(3/21/981)
(3/22/91)
Total Sediment Fed,
kg (Ib)
284 (625)
284 (625)
229 (504)
318 (700)
Weight,
kg (Ib)
85 (187)
76 (168)
62 (136)
80 (175)
Fraction of
Feed
%
30
27
27
25
ther testing would be required to verify this
supposition.
Table 7 combines the scrubber exit flue
gas PCB concentrations noted in Table 5
with sediment feedrate and flue gas flow-
rate data to give the PCB DREs achieved
for the tests. ORE is defined as:
100 • emission rate/feedrate)
As shown in the Table 7, greater than the
regulation-required 99.9999% PCB ORE
was achieved for all three tests.
No PAH compounds analyzed for were
detected in any sample at PQLs of 50 mg/
kg in sediment feed, 1.3 mg/kg in kiln ash,
20 ug/L in scrubber liquor, and 6 ug/dscm
in scrubber exit flue gas.
Results of the scrubber exit flue gas
PCDD/PCDF measurements showed that
total TCDD, PeCDD, HxCDD, and hepta-
CDD (HpCDD) levels were in the nominal
0.01 to 0.02 ng/dscm range for all three
tests, with octa-CDD (OCDD) levels in the
0.03 to 0.06 ng/dscm range. Flue gas PCDF
levels were significantly greater, ranging
up to about 2.8 ng/dscm for total TCDF.
The 2,3,7,8-TCDD toxicity equivalents cor-
responding to the isomer concentrations
measured from nominally 0.05 to 0.10 ng/
dscm over the three tests.
Trace Metal Discharge
Distributions
Two primary objectives of the test pro-
gram were (I) to evaluate the fate of the
contaminant trace metals cadmium, chro-
mium, copper, and lead in the incineration
treatment of the New Bedford Harbor sedi-
ments and (2) to investigate whether
changes in incineration conditions affected
the distribution of these metals in the incin-
erator discharges. Table 8 summarizes the
concentrations of the test metals in sedi-
ment samples and in each of the incinera-
tor discharge streams.
The concentrations of chromium and
copper in resulting kiln ashes were higher
than the composite sediment feed sample
for all tests and were higher for cadmium
and lead for the low-kiln-temperature test
(Test 1). This reflects the weight reduction
in converting sediment to kiln ash during
incineration. However, the cadmium and
lead concentrations in kiln ash were sig-
nificantly lower in the high-kiln-tempera-
ture tests (Tests 2 and 3) when compared
to the Test 1 kiln ash concentrations and
were also lower than the corresponding
sediment feed concentrations. Flue gas
cadmium and lead concentrations, both in
the afterburner exit flue gas and the scrub-
ber exit flue gas, were generally higher for
Tests 2 and 3 than for Test 1. Both trends
are the result of the volatile behavior of
these two metals. The extent of volatiliza-
tion of these metals was evidently higher
in Tests 2 and 3 than in Test 1, giving rise
to lower kiln ash, and generally higherflue
gas, concentrations of these metals for the
highertemperature tests.
Table 8 also notes the TCLP regulatory
limit for the three TCLP metals determined.
Comparing composite feed and kiln ash
Table 5. PCB Analysis Results
Sample
Spiked sediment feed, %
TCLP leachate and scrubber liquor metal
concentrations to the TCLP regulatory lev-
els shows that neither the composite sedi-
ment feed nor any test's kiln ash would be
a TC hazardous waste based on teachable
cadmium, chromium, or lead concentra-
tions.
The scrubber liquor cadmium and chro-
mium concentrations noted in Table 9 are
below the TCLP regulatory level for all
three tests. In contrast, the scrubber liquor
lead concentrations exceed the regulatory
level for all three tests. However, the scrub-
ber liquor metal concentrations noted in
the table are for the total scrubber liquor,
which contains suspended solids. A true
TCLP leachate was prepared from the
three-test composite scrubber liquor that
was held in a storage tank until all analy-
ses were completed. This leachate was
analyzed for lead and found to contain 4.2
mg/L, less than the TCLP regulatory level.
Thus, the scrubber liquor for these tests
was also not a TC hazardous waste.
The metal concentrations shown in
Table 8 can be combined with feed soil
and discharge stream mass flowrate infor-
mation to better show how the metals dis-
tribute among the discharge streams as a
function of incineration condition. These
distributions are summarized in Table 9.
The distribution fractions in Table 9 have
been normalized to the total amount of
each metal measured in all the discharge
streams analyzed. Thus, these normalized
values represent fractions that would have
resulted had mass balance closure in each
PCB Concentration
Aroclor 1242
Aroclor 1254
Test 1
Kiln ash, mg/kg
Scrubber liquor, ug/L
Scrubber exit flue gas, ug/dscm
Test 2
Kiln ash, mg/kg
Scrubber liquor, ug/L
Scrubber exit flue gas, ug/dscm
3.48
133
0.76
96
0.54
84
<0.3
0.22
32
<0.3
0.21
Test 3b
Kiln as/7, mg/kg
Scrubber liquor, ug/L
Scrubber exit flue gas, ug/dscm
Composite native feed, mg/kg
Test 3a
Kiln ash, mg/kg
Scrubber liquor, ug/L
177
<1
<0.26
4,850
57
<1
68
<0.3
<0.09
1,300
44
<0.3
-------
Tabt* ft PCS Decontamination Effectiveness
Parameter
Aroclor 1242
Aroclor 1254
Sediment feed
Concentration, %
Amount fed, kg
KUnAsh
Concentration, mg/kg
Amount discharged, g
Fraction of amount fed, %
Tost 2
Sediment feed
Concentration, %
Amount fed, kg
Kin Ash
Concentration, mg/kg
Amount discharged, g
Fraction of amount fed, %
Toatto
Sediment teed
Concentration, %
Amount fed, kg
Kiln Ash
Concentration, mg/kg
Amount discharged, g
Fraction of amount fed, %
Teat 3b
Sediment feed
Concentration, %
Amount fed, kg
Kiln Ash
Concentration, mg/kg
Amount discharged, g
Fraction of amount fed, %
3.48
9.87
133
11.3
0.11
3.48
9.87
96
7.3
0.07
0.485
1.11
57
3.5
0.32
3.48
11.05
177
14.1
0.13
1.11
3.15
84
7.1
0.22
1.11
3.15
32
2.5
0.08
0.130
0.30
44
2.7
0.91
1.11
3.52
68
5.3
0.15
T*W«7. PCBDREs
Parameter
Test 1
(3/15/91)
Test 2
(3/19/91)
Test 3b
(3/21/91)
Sediment feed
Sediment feedrate, kg/hr 69.5 69.5 69.3
Aroclor 1242 foodrate, g/hr 2,420 2,420 2,410
Aroclor 1254 feedrate, g/hr 773 773 771
Scrubber exit flue gas
FhiB gas flowrate, dscm/mln 33.9 32.9 30.6
Aroclor 1242 concentration ug/dscm 0.76 0.54 <0.26
emission rate, ug/hr 1.6 1.1 <0.5
ORE, % 99.999936 99.999956 >99.999980
Aroclor 1254 concentration ug/dscm 0.22 0.21 <0.09
emission rate, ug/hr 0.5 0.5 <0.2
ORE, % 99.99994 99.99994 >99.99998
case been 100%. Use of distribution frac-
tions normalized in this manner allows
clearer data interpretation, because they
remove variable mass balance closure as
a source of test-to-test data variability.
Actual mass balance closures achieved
around the conventional incineration sys-
tem portion of the RKS ranged from 52%
to 103% for cadmium, 72% to 79% for
chromium, 71% to 86% for copper, and
38% to 66% for lead. These levels are
considered good compared with past ex-
perience on achieving trace metal mass
balance closures from a variety of com-
bustion sources, including incinerators.
Typical mass balance closure results from
this past experience have been, at best, in
the 30% to 200% range.
Several interesting observations
emerge from the data in Table 9. Chro-
mium and copper exhibited relatively
nonvolatile behavior. The kiln ash dis-
charge represented the predominant
fraction of the discharged amount for
these two metals: kiln ash accounted
for 88% to 92% of the chromium and
82% to 89% of the copper. These dis-
tributions were not affected by kiln
temperature in the range tested (i.e.,
824 to 985 °C [1,516 to 1,805 °F]).
In contrast, cadmium and lead exhib-
ited relatively volatile behavior. At the low-
kiln temperature test (Test I) conditions,
the kiln ash accounted for 53% (lead) to
61% (cadmium) of the metals measured in
the discharges. Even at this relatively low
incineration temperature, a significant
amount of each metal evidently vaporized
in the kiln and was carried into the after-
burner and downstream to augment the
amount entrained in flyash carried out of
the kiln.
Evident vaporization was enhanced at
the high-temperature-test (Tests 2 and 3)
condition. For these tests, the kiln ash
accounted for significantly decreased frac-
tions of cadmium and lead measured in
the discharges, 8% to 19% for cadmium
and 19% to 23% for lead. Of the metals
measured and accounted for, scrubber exit
flue gas and scrubber liquor fractions were
higher than the kiln ash fractions at this
high-temperature condition. Indeed, 36%
to 42% of the cadmium discharged and
42% to 55% of the lead measured in the
discharges escaped the incineration sys-
tem and the venturi/packed-column scrub-
ber.
Table 10 summarizes the apparent
scrubber collection efficiencies calculated
for each metal measured in the test pro-
gram. In calculating apparent collection
efficiency, it is assumed that the flowrate
of metals at the scrubber inlet can be
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Table 8. Trace Metals Analysis Results
Sample Cd
Sediment feed
Composite, mg/kg 7.4
Composite TCLP leachate, mg/L 0.11
Test 1 (3/15/91)
Kiln ash, mg/kg 9.5
Kiln ash TCLP leachate, mg/L 0.26
Afterburner exit flue gas, ug/dscm 42.3
Scrubber exit flue gas, ug/dscm 34.9
Scrubber liquor, mg/L 0. 14
Test 2 (3/19/91)
Kiln ash, mg/kg 2.7
Kiln ash TCLP leachate, mg/L 0.046
Afterburner exit flue gas, ug/dscm 77.6
Scrubber exit flue gas, ug/dscm 55.3
Scrubber liquor, mg/L 0.27
Test 3a (3/21/91)
Kiln ash, mg/kg 2.3
Test3b (3/21/91)
Kiln ash, mg/kg 2.0
Kiln ash TCLP leachate, mg/L 0.043
Afterburner exit flue gas, ug/dscm 51.6
Scrubber exit flue gas, ug/dscm 79.0
Scrubber liquor, mg/L 0.73
TCLP regulatory level, mg/L 1.0
• = Not a TCLP metal.
Table 9. Normalized Trace Metal Distributions
Test 1 2
(3/15/91) (3/19/91)
Kiln exit temperature, °C 824 984
(°F) (1,516) (1,802)
Kiln exitOs, % 11.2 9.0
Cr
161
0.041
376
0.048
219
158
1.9
434
0.030
136
73.2
1.4
367
357
0.03
126
83.9
1.3
5.0
3b
(3/21/91)
985
(1,805)
10.0
Cu Pb
-
308 236
0.066 1.2
608 277
6.3 0.71
571 1,030
421 903
4.5 8.8
828 75.6
3.01 0.17
768 1,814
436 1,273
2.6 5.4
785 96
721 62
3.0 0.41
519 984
750 2,020
3.4 5.6
—' 5.0
Apparent distribution, % of metal measured
Cadmium
Kiln ash 61 19
Scrubber exit flue gas, 23 42
Scrubber liquor 16 39
Total 100 100
Chromium
Kiln ash 88 92
Scrubber exit flue gas, 4 2
Scrubber liquor 8 6
Total 100 100
Copper
Kiln ash 83 89
Scrubber exit flue gas, 6 5
Scrubber liquor 11 6
Total 100 100
Lead
Kiln ash 53 23
Scrubber exit flue gas, 17 42
Scrubber liquor 30 35
Total 100 100
8
36
56
100
92
2
6
100
82
10
8
100
19
55
26
100
obtained by summing the flows in the two
scrubber discharge streams: the scrubber
exit flue gas and the scrubber liquor. Ap-
parent scrubber collection efficiency is de-
fined as the scrubber liquorfraction divided
by the sum of the scrubber liquor fraction
and the scrubber exit flue gas fraction. The
data in Table 1 0 show that, at the low-kiln-
temperature test condition, apparent col-
lection efficiencies for chromium, copper,
and lead were comparable, and in the
nominal 65% to 70% range. Collection effi-
ciency for cadmium was lower at 41%. At
the high-kiln-temperature test conditions,
cadmium and chromium efficiencies were
relatively unchanged. Copper and lead col-
lection efficiencies decreased.
Paniculate and HCI Emissions
Data
For the three tests, flue gas particulate
levels at the scrubber exit ranged from 70
to 1 01 mg/dscm (0.03 to 0.04 grains/dscf),
corrected to 7% O2. These levels were
below the 180 mg/dscm at (0.08 grains/
dscf), 7% O2, hazardous waste incinerator
performance standard.
The sediments incinerated during this
test program contained 0.85% chlorine. "
Measured HCI concentrations at the scrub-
ber exit ranged from 0.2 to 2.4 ppm, with
corresponding emission rates ranging from
0.7 to 7.2 g/hr. These emission rates were
less than the hazardous waste incinerator
performance standard floor of 2 kg/hr. The
scrubber system HCI collection efficien-
cies ranged from 98.8% to 99.9% of the
chlorine fed.
Conclusions
Test conclusions are as follows:
• Greater than 99.9999% ORE of the
PCBs in the site sediments can be
achieved in the scrubber exit flue gas,
as calculated by the regulatory defini-
tion, at incineration temperatures of
both 824°C (1,516°F) and 984°C
(1 ,803°F) in a rotary kiln with an af-
terburner operated at 1,208°C
(2,206°F). However, when sediments
that had not been dewatered were
Table 10. Apparent Scrubber Collection Efficiencies
Test
7 2 3b
(3/15/91) (3/19/91) (3/21/91)
Kiln exit temperature, "C 824 984 985
Kiln exitOz, %
Cadmium
Chromium
Copper
Lead
(°F) (1,516) (1,803) (1,805)
1 1.2 9.0 10.0
Apparent Scrubber Collection Efficiency, %
41 48 50
69 79 62
66 53 33
64 45 23
•U.S. Government Printing Office: 1992— 648-080/60068
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incinerated at a kiln solids residence
time of 0.5 hr, the treated sediments
(kiln ash) were still PCB-contaminated.
In tests with a PCB-spiked sediment
feed, the kiln ash discharge accounted
for between 0.08% to 0.14% of the
FOB fed regardless of kiln tempera-
ture. For a native (unspiked) sedi-
ment feed, the kiln ash accounted for
0.44% of the PCBs feed.
Of the contaminant trace metals, chro-
mium and copper were relatively non-
volatile. The kiln ash discharge ac-
counted for nominally 80% to 90% of
the measured discharged amounts of
these metals. These fractions were
not affected by the range of kiln tem-
peratures tested.
Of the contaminant trace metals, cad-
mium and lead exhibited relatively
volatile behavior, and increasingly so
at the high kiln exit gas temperature
(984°C [1,803°F]). The kiln ash dis-
charge contained 53% of the lead
and 61% of the cadmium accounted
for in the discharges at the low kiln
temperature (824°C [1,516°F]). These
fractions decreased to the nominal
10% to 20% range for cadmium and
the 20% range for lead at the high
kiln temperature. Scrubber exit flue
gas fractions (cadmium and lead) and
scrubber liquor fractions (cadmium)
increased accordingly. Mass balance
closures achieved were 52% to 62%
for cadmium in two of the three tests
performed, and ranged from 38% to
66% for lead over the three tests.
Based on recovered scrubber liquor
-and scrubber exit flue gas concentra-
tions, apparent scrubber collection ef-
ficiencies were in the nominal 65% to
70% range for chromium, copper, and
lead at the low kiln temperature, and
lower, at 41%, for cadmium. Cadmium
and chromium collection efficiencies
were apparently unaffected by in-
creased kiln temperature, although
copper and lead collection efficiency
decreased to the 33% to 53% range
for copper and the 23% to 45% range
for lead.
• Neither treated sediments nor the
scrubber liquor discharges would ex-
hibit the TC based on their cadmium,
chromium, or lead concentrations.
The test results suggest that incinera-
tion would be an effective treatment option
for the site sediments. However, sediment
dewatering before incineration, or inciner-
ating at higher kiln solids residence times
(perhaps up to 1 hr), might be required to
yield a treated sediment not contaminated
by PCBs.
The full report was submitted in fulfill-
ment of Contract No. 68-C9-0038 by Acurex
Corporation under the sponsorship of the
U.S. Environmental Protection Agency.
W. E. Whttworth and L R. Waterland are with Acurex Corporation, Jefferson, AR
72079.
R.C. Thurnau is the EPA Project Officer (see below).
The complete report, entitled "Pilot-Scale Incineration of PCB-Contaminated Sedi-
ments from the New Bedford Harbor Hot Spot Superfund Site," (Order No. PB92-
178953/AS; Cost: $26.00; 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, Ohio 45258
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/SR-92/068
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