PILOT-SCALE INCINERATION OF PC B-C O NT AM I NATE D SEDIMENTS FROM THE HOT SPOT OF THE
NEW BEDFORD HARBOR SUPERFUND SITE
L. R. Waterland and W, E, Whitworth
Acurex Environmental Corporation
Incineration Research Facility
Jefferson, Arkansas 72079
M.KL Richards
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268
ABSTRACT
A detailed test program was performed at the U.S. Environmental Protection Agency's (EPA's) Incin-
eration Research Facility (IRF) to define the incineration characteristics of contaminated marine sediments
from the Hot Spot in New Bedford Harbor, a Superfund site near New Bedford, MA. The sediments at this
site are contaminated with PCB concentrations of 4,000 to over 200,000 mg/kg, as well as with trace metals,
chiefly cadmium, chromium, copper, and lead, at concentrations 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 performed using native sediments spiked with pure PCB Askarel trans-
former fluid. The third test also included a period of operation with native (unspikcd) 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 destruction and removal
efficiency (DRE) 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). Average test temperatures achieved were 824"
and 984°C (1,516° and 1,803°F).
Test results show that greater than 99.9999% PCB DRE (100 * [1 - flue gas emission rate/feedrate]) was
achieved at both kiln temperatures with the afterburner 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 discharge 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
contained 100 mg/kg of PCBs, which accounted for 0.44% of the PCBs introduced 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-tctra-CDD (2,3,7,8-TCDD) toxicity 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
accounted for nominally 80% to 90% of the discharged amount of these metals. 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 decreased
to the nominal 10% to 20% range for cadmium and the 20% range for lead. Scrubber exit flue gas fractions
(cadmium and lead) and scrubber liquor fractions (cadmium) increased accordingly. Neither treated sedi-
ments 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 characteristic
leaching procedure (TCLP) leachate was near the TC regulatory level. This suggests that the scrubber liquor
discharge from a wet scrubber could be a TC hazardous waste in the incineration of higher-than-tested
lead-containing sediments, or under extended scrubber operation at minimum blowdown.
Test results suggest that incineration would be an effective treatment option for the site sediments.
However, sediment dewatering before incineration, and/or incinerating at longer kiln solids residence times
might be required to yield a treated sediment not contaminated by PCBs. If a wet scrubber were used for
particulate and acid gas control, the scrubber blowdown discharge might require further treatment to stabilize
leachable lead levels. In addition, lead levels in flue gas emissions from a wet scrubber air pollution control
system (APCS) might be of concern.
The information described in this paper has been funded wholly or in part by the United States
Environmental Protection Agency under Contract No. 68-C9-0038 to Acurex Environmental Corporation. It
has been subjected to Agency review, and approved for publication. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.

-------
346 Waterland NEW BEDFORD SUPERFUNP SITE
INTRODUCTION
EPA Region 1 is conducting the remedial design (RD)
for the remediation of a Superfund site located in New Bed-
ford Harbor near New Bedford, MA. According to the record
of decision (ROD) document of 1990, the EPA has identified
approximately 10,000 yd3 of contaminated sediment 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 requested that test burns be conducted at EPA's
IRF to support the RD for this Superfund site.
The primary objective of this test program was to obtain
data to support the RD plans and specifications. Therefore,
the test conditions were designed to evaluate the effectiveness
of varying incinerator operating conditions in the destruction
of PCBs and other pollutants. Specifically, the test program
attempted to answer these questions:
•	Can incineration effectively destroy PCBs to the re-
quired regulatory level DRE of 99.9999% in the flue
gas emission?
•	What is the distribution of the contaminant trace
metals in the discharge streams during incineration
of the sediment?
•	What are the effects of incineration excess air and
temperature on organic constituent destruction and
metals distributions, including the lcachability of the
metals from the kiln ash?
•	What is the effectiveness of the air pollution control
system (APCS), with design and operating character-
istics similar to those of the IRF vcnturi/packcd-col-
umn scrubber, in collecting 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 destruction 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 Fig. 1. The
IRF RKS consists of a primary combustion chamber, a tran-
sition section, and a fired afterburner chamber. After exiting
the afterburner, flue gas flows through a quench section fol-
lowed 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 sec-
ondary 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
characterization sample representing each drum was shipped
to the IRF for pretest analyses. These samples were subjected
to proximate, PCB, and hazardous constituent 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% DRE 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. Consequently, it
was decided to spike the test sediment to higher PCB concen-
trations to provide a margin in the ability to establish
99.9999% DRE. The material used to spike the sediments was
an Askarel transformer fluid comprised of roughly 75%
SINCIE-STAGE IONIZING
WET SCRUBBER
SCRUBBER
UQUOR
RECIRCULATION
QUENCH
AFTERBURNER
AIR
10 FAN
NATURAL
LIQUID
AFTERBURNER
SOLIDS
FEEDER
PACKED
COLUMN
TRANSFER
SCRUBBER
DUCT
BURNER
VENTURI
SCRUBBER
SCRUBBER
LIOUOR
RECIRCULATION
NATURAL
GAS.
LIQUID FEED
ROTARY
KILN
CARBONBEO HEPA
ADSORBER FILTER
ROTARY KILN
INCINERATOR
MODULAR PRIMARY AIR
POLLUTION CONTROL
SYSTEM DEVICES
REDUNDANT AIR
POLLUTION CONTROL
SYSTEM
Fig. 1. Schematic of the IRF rotary kiln incineration system.

-------
Waterland NEW BEDFORD SUPERFUND SITE 347
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 sediments
were repackaged into 1.5-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.
Test Conditions
The test series was designed to evaluate the effects of
incinerator operating conditions 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 tempera-
tures 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 I were to be held at the nominal
values noted in the tabic.
Table II summarizes the actual incinerator exit tempera-
tures and flue gas levels, including their ranges and averages
for each test during flue gas sampling. These are compared
TABLE I
Incinerator System Operating Conditions Held Constant
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 re-
sulted from higher than expected air inleakage into the kiln
chamber because of the inability to tightly secure a rotating
kiln seal. The minimum 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 environ-
ments. Consequently, it was not possible to test kiln excess air
as a variable.
Sampling and Analysis Procedures
The scope of the sampling effort undertaken during this
test program is illustrated in Fig. 2, in which the sampling
locations are identified. Specifically, the sampling effort dur-
ing 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 sediments 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 li-
quor.
•	Continuously measuring O2 levels in the kiln exit and
afterburner exit flue gases; O2, CO, CO2, NOx, and
total unburncd hydrocarbon (TUHC) levels at the
venturi/packed-column scrubber exit; and O2, CO,
and CO2 levels in the stack.
•	Sampling flue gas at the scrubber system exit for
PAHs and PCBs.
•	Sampling flue gas at the scrubber system exit for
PCDDs and PCDFs.
Operating condition
Value -
Kiln solids residence time
Total sediment fecdrate
Scrubber blowdown rale
Venturi liquor (lowratc
Vcnturi pressure drop
Packed tower liquor flowrate
Scrubber liquor temperature
0.5 hr
68.2 kg/hr (150 lb/hr)
0 L/min (0 gpm) or
minimum operable
76 L/min (20 gpm)
6.2 kPa (25 in WC)
115 L/min (30 gpm)
49°C (120°F)
O'JHNtR
QUENCH
SECTION
YENTUREPACKED
COLUMN
SCflU68£A

CAflBON

HEP*

BEO

FILTtR
Sampllof
poUt
Sediment
fe«d
(ctxnpoiite)
Kilo ash
(composite
Veoturl/
packed-coluuDQ
Krobbcr liquor
(composite)
Cootiououi
Que pi
mooltorlag
(CEMi)
Melbod 0010
(PCBiand
PAHs)
Method
0010
(PCDDt/
PCDFi)
Method
0030
(VoUUIe
orioles)
Particle ilu
distribution
(Cascade
Impactor)
Method S Method 5
(Particulate, (Particulate,
tract metals) HO)
X
X
X
X
X
X
Fig. 2. Sampling matrix

-------
348 Waterland NEW BEDFORD SUPERFUND SITE
TABLE II
Actual Versus Target Operating Conditions for the New Bedford Harbor Tests


Temperature, °C (°F)
Flue gas O2, %
Test
Date
Target
Minimum
Maximum
Average
Target
Range
Average
Kiln exit
1
3/15/91
816 (1,500)
755 (1,391)
907 (1,665)
824 (1,516)
6
5.8 to 13.9
11.2
2
3/19/91
982(1,800)
945 (1,733)
1,022 (1,871)
984 (1,803)
6
6.6 to 12.0
9.0
3a
3/21/91
982 (1,800)
939 (1,723)
1,010 (1,850)
981 (1,797)
10
7.2 to 11.5
9.3
3b
3/21/91
982 (1,800)
968 (1,775)
999 (1,831)
985 (1,805)
10
7.0 to 11.4
10.0
Afterburner exit
1
3/15/91
1,204 (2,200)
1,195 (2,183)
1,221 (2,229)
1,208 (2,206)
7
3.2 to 8.2
6.4
2
3/19/91
1,204 (2,200)
1,201 (2,194)
1,213 (2,216)
1,208 (2,206)
7
3.6 to 7.4
6.0
3a
3/21/91
1,204 (2,200)
1,194 (2,181)
1,226 (2,239)
1,208 (2,206)
7
2.9 to 7.6
6.4
3b
3/21791
1,204 (2,200)
1,198 (2,188)
1,214 (2,217)
1,208 (2,206)
7
4,3 to 8.0
7.0
•	Sampling flue gas at the scrubber system exit for
volatile organics.
•	Sampling flue gas upstream of the scrubber system
for particle size distribution.
•	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 scrubber system and at
the stack downstream of the secondary APCS for
particulate and HC1 using Method 5 to comply with
permit requirements.
An aliquot of the composited sediment feed and each
test's kiln ash was subjected to the TCLP leaching procedure
and analyzed for cadmium, chromium, copper, and lead.
Waste feed samples, kiln ash samples, and scrubber liquor
samples were analyzed separately for PCBs, PAHs, and cad-
mium, chromium, copper, and lead. The composite sediment
feed sample was also subjected to proximate (moisture, ash
content, and heat content) analysis and ultimate (C, H, O, N,
S, CI) analysis.
TEST RESULTS
The results of the test program are discussed in the
subsections that follow. Test results are grouped by analyte
class.
PCB, Semlvolatlle and Volatile Organic, and Dioxln/Furan
Analysis Results
Table III summarizes the PCB contents of each incinera-
tion test sample. As noted in the table, the spiked sediment
feed contained 3.48% Aroclor 1242 and 1.11% Aroclor 1254.
The kiln ash resulting from the incineration of the sediments
(both spiked and native), without dewatering, had substan-
tially reduced, though still significant, PCB contents. The kiln
ash for the spiked wet sediment feeds contained between
96 and 177 mg/kg of Aroclor 1242, and between 32 and
84 mg/kg of Aroclor 1254. Interestingly, within the range of
TABLE III
PCB Analysis Results

PCB Concentration

Aroclor
Aroclor
Sample
1242
1254
Spiked sediment feed, %
3.48
1.11
Test 1:


Kiln ash, mg/kg
133
84
Scrubber liquor,/ig/L
<1
<03
Scrubber exit flue gas,^g/dscm
0.76
0.22
Test 2:


Kiln ash, mg/kg
96
32
Scrubber liquor,/ig/L
<1
<03
Scrubber exit flue gas,^g/dscm
0.54
0.21
Test 3b:


Kiln ash, mg/kg
177
68
Scrubber liquor,
<1
<03
Scrubber exit flue gas, ^ug/dscm
<0.26
<0.09
Composite native feed, mg/kg
4,850
1300
Test 3a;


Kiln ash, mg/kg
57
44
Scrubber liquor,/ig/L
<1
<03
the variability of the data, the higher kiln temperature tested
for Tests 2 and 3 did not result in significantly lower kiln ash
PCB concentrations than the lower temperature tested in
Test 1. The kiln ash resulting from native sediment feed incin-
erated 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 limits (PQLs) of 1 ^g/L for
Aroclor 1242 and 03 pgfL for Aroclor 1254. The scrubber
exit flue gas contained low, though measurable, levels of both
PCB formulations in Tests 1 and 2.

-------
Waterland NEW BEDFORD SUPERFUND SITE 349
Table IV summarizes the degree of PCB decontamina-
tion achieved in each test, in terms of the fraction of the
amount of PCB introduced in the incinerator feed 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 accounted for in the kiln ash
produced. The remaining 99.8 to 99.9% was removed and
largely destroyed, as discussed below. 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.
TABLE IV
PCB Decontamination Effectiveness
Parameter
Aroclor 1242
Aroclor 1254
Test 1:


Sediment feed


Concentration, %
3.48
1.11
Amount fed, kg
9.87
3.15
Kiln ash


Concentration, mg/kg
133
84
Amount discharged, g
11.3
7.1
Fraction of amount fed, %
0.11
0.22
Test 2:


Sediment feed


Concentration, %
3.48
1.11
Amount fed, kg
9.87
3.15
Kiln ash


Concentration, mg/kg
96
32
Amount discharged, g
73
2.5
Fraction of amount fed, %
0.07
0.08
Test 3a:


Sediment feed


Concentration, %
0.485
0.130
Amount fed, kg
1.11
030
Kiln ash


Concentration, mg/kg
57
44
Amount discharged, g
3.5
2.7
Fraction of amount fed, %
032
0.91
Test 3b:


Scdiment'feed


Concentration, %
3.48
1.11
Amount fed, kg
11.05
3-52
Kiln ash


Concentration, mg/kg
177
68
Amount discharged, g
14.1
5.3
Fraction of amount fed, %
0.13
0.15
The data shown in Tables III and IV confirm that incin-
eration under the conditions 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 decontam-
ination, as was the kiln solids residence time (0 J hr). The New
Bedford Harbor marine sediments, however, contained sub-
stantial moisture; the composite sediments tested were 64%
moisture. Evidently, with such high moisture content, solids
bed temperatures were not raised to levels needed for more
complete PCB destruction in the residence time available.
Longer solids residence times, 1 hr in the IRFs experience,
would have likely allowed more complete PCB decontamina-
tion. Further testing would be required to verify this supposi-
tion.
Table V takes the scrubber exit flue gas PCB concentra-
tions noted in Table V and combines them with sediment
feedrate and flue gas flowrate data to give the PCB DREs
achieved for the tests. DRE is defmed as:
100 • (1-emission rate/feedrate)
As shown in the Table III, greater than the regulation-re-
quired 99.9999% PCB DRE 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, 13 mg/kg in
kiln ash, 2Q/*g/L in scrubber liquor, and 6^g/dscm in scrubber
exit flue gas.
Results of the scrubber exit flue gas PCDD/PCDF mea-
surements showed that total tetra-CDD (TCDD), penta-
CDD (PeCDD), hexa-CDD (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 signif-
icantly greater, ranging up to about 2.8 ng/dscm for total
TCDF. The 2,3,7,8-TCDD toxicity equivalents corresponding
to the isomer concentrations measured ranged from nomi-
nally 0.05 to 0.10 ng/dscm over the three tests.
Trace Metal Discharge Distributions
Two primary objectives of the test program were (1) to
evaluate the fate of the contaminant trace metals cadmium,
chromium, copper, and lead in the incineration treatment of
the New Bedford Harbor sediments (2) and to investigate
whether changes in incineration conditions affected the dis-
tribution of these metals in the incinerator discharges.
Table VI summarizes the concentrations of the test metals in
sediment samples and in each of the incinerator discharge
streams.
The concentrations of chromium and copper in resulting
kiln ashes were higher than the composite sedimeat 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 going from sediment to kiln ash during
incineration. However, the cadmium and lead concentrations
in kiln ash were significantly 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 correspond-
ing sediment feed concentrations. Flue gas cadmium and lead
concentrations, both in the afterburner exit flue gas and the
scrubber exit flue gas were generally higher for Tests 2 and 3
than for Test 1 as well. Both these 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 higher
flue gas, concentrations of these metals for the higher temper-
ature tests.
Table VI also notes the TCLP regulatory limit for the
three TCLP metals determined. Comparing composite feed
and kiln ash TCLP leachate and scrubber liquor metal con-
centrations to the TCLP regulatory levels shows that neither
the composite sediment feed nor any test's kiln ash would be
a TC hazardous waste based on leachable cadmium, chro-
mium, or lead concentrations.

-------
350 Waterland NEW BEDFORD SUPERFUND SITE
TABLE V
PCB DREs
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
693
Aroclor 1242 feedrate, g/hr
2,420
2,420
2,410
Aroclor 1254 feedrate, g/hr
773
773
771
Scrubber exit flue gas:



Flue gas flowrate, dscm/min
33.9
32.9
30.6
Aroclor 1242 concentration, /ig/dscm
0.76
0.54
<0.26
emission rate,/ig/hr
1.6
1.1
<0.5
DRE, %
99.999936
99.999956
>99.999980
Aroclor 1254 concentration, /99.99998
TABLE VI
Trace Metals Analysis Results
Sample
Cd
Cr
Cu
Pb
Sediment Teed:




Composite, mg/kg
7.4
161
308
236
Composite TCLP leachate, mg/L
0.11
0.041
0.066
1.2
Test 1 (3/15/91):




Kiln ash, mg/kg
9.5
376
608
277
Kiln ash TCLP leachate, mg/L
0.26
0.048
63
0.71
Afterburner exit flue gas, ^g/dscm
423
219
571
1,030
Scrubber exit flue gas,/ig/dscm
34.9
158
421
903
Scrubber liquor, mg/L
0.14
1.9
• 4.5
8.8
Test 2 (3/19/91):




Kiln ash, mg/kg
2.7
434
828
75.6
Kiln ash TCLP leachate, mg/L
0.046
0.030
3.01
0.17
Afterburner exit flue gast(«g/dscm
77.6
136
768
1,814
Scrubber exit flue gas,^g/dscm
553
73.2
436
1,273
Scrubber liquor, mg/L
0.27
1.4
2.6
5.4
Test 3a (3/21/91):




Kiln ash, mg/kg
2.3
367
785
96
Test 3b (3/21/91):




Kiln ash, mg/kg
2.0
357
721
62
Kiln ash TCLP leachate, mg/L
0.043
0.03
3.0
0.41
Afterburner exit flue gas,/ig/dscm
51.6
126
519
984
Scrubber exit flue gas,/ig/dscm
79.0
83.9
750
2,020
Scrubber liquor, mg/L
0.73
13
3.4
5.6
TCLP regulatory level, mg/L
1.0
5.0
a
5.0
a — = Not a TCLP metal.
The scrubber liquor cadmium and chromium concentra-
tions noted in Table VT are below the TCLP regulatory level
for all three tests. In contrast, the scrubber liquor lead con-
centrations exceed the regulatory level for all three tests.
However, the scrubber 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 analyses 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.

-------
Waterland NEW BEDFORD SUPERFUND SITE 351
The metal concentrations shown in Table VI can be com-
bined with feed soil and discharge stream mass flowrate infor-
mation to better show how the metals distribute among the
discharge streams as a function of incineration condition.
These distributions are summarized in Table VII. The distri-
bution fractions in Table VII 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 case been 100%. Use of distribution fractions normal-
ized in this manner allows clearer data interpretation, because
they remove variable mass balance closure as a source of
tcst-to-test data variability.
Actual mass balance closures achieved around the con-
ventional incineration system 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 experience on achieving
trace metal mass balance closures from a variety of combus-
tion 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 VII. Chromium and copper exhibited relatively nonvol-
atile behavior. The kiln ash discharge represented the pre-
dominant fraction of the discharged amount for these two
metals; kiln ash accounted for 88% to 92% of the chromium
measured in the discharges and 82% to 89% of the copper.
These distributions 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 exhibited relatively volatile
behavior. At the low-kiln-temperature test (Test 1) condi-
tions, the kiln ash accounted for 53% (lead) to 61% (cad-
mium) 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 afterburner and downstream to augment the amount
entrained in flyash carried out of the kiln.
Evident vaporization was enhanced at the high-tempera-
ture-test (Tests 2 and 3) condition. For these tests, the kiln ash
accounted for significantly decreased fractions of cadmium
and lead measured in the discharges, 8% to 19% for cadmium
and 19% to 23% for lead. Of the metals measured and ac-
counted for, scrubber exit flue gas and scrubber liquor frac-
tions were higher than the kiln ash fractions at this
high-temperature condition. Indeed, 36% to 42% of the cad-
mium discharged and 42% to 55% of the lead measured in the
discharges escaped the incineration system and the ven-
turi/packed-column scrubber.
Table VIII summarizes the apparent scrubber collection
efficiencies calculated for each metal measured in the test
program. In calculating apparent collection efficiency, it is
assumed that the flowrate of metals at the scrubber inlet can
be obtained by summing the flows in the two scrubber dis-
charge streams: the scrubber exit flue gas and the scrubber
liquor. Apparent scrubber collection efficiency is defined as
scrubber liquor fraction divided by the sum of scrubber liquor
fraction and scrubber exit flue gas fraction. The data in
Table VIII show that, at the low-kiln-temperature test condi-
tion, apparent collection efficiencies for chromium, copper,
Test
1
2
3b

(3/15/91)
(3/19/91)
(3/21/91)
Kiln exit temperature, °C
824
984
985
(°F)
(1,516)
(1,803)
(1,805)
Kiln exit Oz, %
11.2
9.0
10.0

Apparent distribution, % of metal measured
Cadmium
61
19
8
Kiln ash
23
42
36
Scrubber exit flue gas
16
39
56
Scrubber liquor
100
100
100
Total



Chromium



Kiln ash
88
92 ¦'
92
Scrubber exit flue gas
4
2
2
Scrubber liquor
8
6
6
Total
100
100
100
Copper



Kiln ash
83
89
82
Scrubber exit flue gas
6
5
10
Scrubber liquor
11
6
8
Total
100
100
100
Lead



Kiln ash
53
23
19
Scrubber exit flue gas
17
42
55
Scrubber liquor
30
35
26
Total
100
100
100
TABLE VII
Normalized Trace Metal Distributions

-------
352 Waterland NEW BEDFORD SUPERFUND SITE
TABLE VIII
Apparent Scrubber Collection Efficiencies
Test
1
2
3b

(3/15/91)
(3/19/91)
(3/21/91)
Kiln exit temperature, "C
824
984
985
CF)
(1,516)
(1,803)
(1,805)
Kiln exit O2. %
11.2
9.0
10.0

Apparent scrubber collection efficiency, %
Cadmium
41
48
50
Chromium
69
79
62
Copper
66
53
33
Lead
64
45
23
and lead were comparable, and in the nominal 65% to 70%
range. Collection efficiency for cadmium was lower at 41%.
At the high-kiln-temperature test conditions, cadmium and
chromium efficiencies were relatively unchanged. Copper and
lead collection efficiencies decreased.
Particulate and HC1 Emissions Data
For the three tests, flue gas particulate levels at the scrub-
ber exit ranged from 70 to 101 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, hazard-
ous waste incinerator performance standard.
The sediments incinerated during this test program con-
tained 0.85% chlorine. Measured HC1 concentrations at the
scrubber 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 perfor-
mance standard floor of 2 kg/hr. The scrubber system HC1
collection efficiencies ranged from 98.8% to 99.9% of the
chlorine fed.
CONCLUSIONS
Test conclusions are as follows:
•	Greater than 99.9999% DRE of the PCBs in the site
sediments can be achieved in the scrubber exit flue
gas, as calculated by the regulatory definition, at
incineration temperatures of both 824°C (1,516°F)
and 984°C (1,803°F) in a rotary kiln with an after-
burner operated at 1,208°C (2,206°F). However,
when sediments that had not been dewatercd were
incinerated at a kiln solids residence time of 0.5 hr,
the treated sediments (kiln ash) were still PCB-con-
taxninated. In tests with a PCB-spiked sediment feed,
the kiln ash discharge accounted for between 0.08%
to 0.14% of the PCB fed regardless of kiln tempera-
ture. For a native (unspiked) sediment feed, the kiln
ash accounted for 0,44% of the PCBs feed.
•	Of the contaminant trace metals, chromium and cop-
per were relatively nonvolatile. The kiln ash dis-
charge accounted 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, cadmium and lead
exhibited relatively volatile behavior, and increas-
ingly so at the high kiln exit gas temperature (984°C
[1,803^]). The kiln ash discharge 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 concentrations, apparent scrubber col-
lection efficiencies were in the nominal 65% to 70%
range for chromium, copper, and lead at the low kiln
temperature, and lower, at 41%, for cadmium. Cad-
mium and chromium collection efficiencies were ap-
parently unaffected by increased kiln temperature,
although copper and lead collection efficiency de-
creased 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 exhibit the TC based on their cad-
mium, chromium, or lead concentrations.
The test results suggest that incineration would be an
effective treatment option for the site sediments. However,
sediment dewatering before incineration, or incinerating at
higher kiln solids residence times (perhaps up to 1 hr), might
be required to yield a treated sediment not contaminated by
PCBs.

-------