United States
Environmental Protection
Agency
Hazardous Waste Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-87/017 May 1987
v>EPA Project Summary
Characterization of Hazardous
Waste Incineration Residuals
Donald Van Buren, Gary Poe, and Carlo Castaldini
The Office of Solid Waste and Emer-
gency Response (OSWER-EPA) is con-
sidering establishment of a criterion for
land disposal of waste or residue. This
criterion is based on the achievement of
residue quality equivalent to that from
effective incineration. The purpose of
this study was to provide data on the
quantities and characteristics of solid
and liquid discharges from hazardous
waste incineration facilities. A total of
10 facilities were sampled comprising
major incineration designs and flue gas
treatment devices. All inlet and outlet
liquid and solid streams were sampled
and subjected to extensive analyses for
organic and inorganic pollutant concen-
trations. Laboratory analyses for solid
discharge streams also included
leachate evaluations using standard
EPA toxicrty tests for metals and a draft
Toxicity Characteristic Leaching Proce-
dure (TCLP) for volatile and
semivolatile organics and metals. Mon-
itored data on incinerator facility opera-
tion was then used to determine the
discharge rates of detected pollutants.
This Project Summary was devel-
oped by EPA's Hazardous Waste Engi-
neering Research Laboratory, Cincin-
nati, OH, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
Under the 1985 amendments to the
Resource Conservation and Recovery
Act (RCRA), the Environmental Protec-
tion Agency (EPA) is required to ban the
land disposal of many hazardous
wastes unless their safe disposal can be
demonstrated. The Office of Solid
Waste and Emergency Response
(OSWER) is considering the establish-
ment of a criterion to require residue
quality equivalent to that from effective
incineration before residue land dis-
posal of waste or residue. EPA's Office
of Research and Development (ORD)
characterized stack gas emissions from
incinerators under a field testing pro-
gram in.support of OSWER's regulation
development process. This testing, con-
ducted at eight full-scale operating in-
cinerators, assessed the incinerator's
achievement of a required destruction
and removal efficiency (ORE) of 99.99
percent(1). Previously, some analysis of
bottom ash, flyash, and scrubber dis-
charge liquid was conducted. The latter
effort, described herein, was under-
taken to achieve a more comprehensive
characterization of incinerator bottom
ash and flyash from a greater number of
hazardous waste incineration facilities.
In addition to meeting OSWER's quality
criterion for residues, the Office of
Water's (OW) pretreatment discharge
standards will apply to facilities that
treat, store, or dispose of hazardous
wastes (TSDs). There exists, therefore, a
need to characterize any wastewater
discharged from an incinerator burning
hazardous wastes.
Approach
Criteria for candidate test site selec-
tion were based on site availability, op-
erational status and types of wastes in-
cinerated. Preference was given to
those facilities incinerating solid
wastes, generating ash and employing
air pollution control devices and to
those previously tested for air emis-
sions and thermal destruction. Ten sites
were selected, representing a broad
range of design and operating practice.
Six employed rotary kilns; three, fixed
-------
hearths; and one, a fluidized bed. The
six rotary kilns burned liquid wastes
downstream of rotary combustors. Air
pollution control equipment (APCE)
ranged from uncontrolled to primarily
wet controls. Two sites had no control
equipment. All except those two had a
quench system and a scrubber. Two
sites had wet scrubbers and also em-
ployed wet electrostatic precipitators.
Table 1 summarizes the ten incineration
configurations.
During the site visits, the wastes fired
were typical of those normally inciner-
ated. In two cases, solid hazardous
wastes were selected to provide a more
uniform feed to promote production of
a more representative sample. The
wastes were not spiked as is usual in
source testing operations. Table 2 sum-
marizes the sampled input and output
streams and the analyses performed.
The typical test involved sampling non-
gaseous incinerator inlet and outlet
streams during a 2- to 4-hour period of
operation. At Sites 2, 7, and 8, not all
streams were sampled due to safety
and/or proprietary concerns. Wastes
not sampled included lab packs, hospi-
tal wastes, nitrites magnesium scrap,
and, at one site, all drummed wastes.
Concurrent with sampling, system op-
erating information was also obtained
to substantiate normal operation.
The samples were analyzed for
volatile and semivolatile organics and
priority pollutant metals in accordance
with EPA/OSWER procedures (2). Ash
samples were also analyzed for
leachate organics and metals. Two ex-
traction procedure (EP) toxicity test
methods were used, namely Method
1310 in SW-846, the EP Toxicity Test
Procedure, and a draft TCLP using the
EPA draft protocol (3). Extracts from the
former were analyzed for priority pollu-
tant metals. Extracts from the latter
were analyzed for priority pollutant
metals and semivolatile organics, and
for volatile organics, using a zero-head
extraction vessel (ZHEV).
Results
Volatiles and Semivolatile
Organics
A total of 19 volatile organics and 24
semivolatile organics were detected in
the ash residual samples. Those present
in the highest concentrations were
toluene (120 ppm), 2-butanone (34
ppm), 4-methyl-2-pentanone (29 ppm),
and tetrachloroethane (16 ppm). Even
the low volatiles concentrations re-
ported in the ash would generally not be
expected. However, these levels might
be due to the ash adsorbing volatiles
from quench water (Sites 1, 2, 3, 7, 8,
and 9), flue gas, or air; products of in-
Table 1. Hazardous Waste Incinerator Configurations and Waste IDs
Site No. Incinerator type 1
Rotary kiln with
secondary com-
bustor in parallel
with a liquid
waste-fired boiler
2 34
Rotary kiln Rotary kiln Fluidized
with secondary with sec- bed incin-
combustor in ondary erator
parallel with a combustor
liquid injection
combustor
5 67
Fixed hearth Fixed Fixed
(2 separate hearth hearth
incineration with sec-
systems) ondary
8
Rotary kiln with
(secondary) liq-
uid injection
combustor.
combustor Drums also con-
veyed through
combustor
9 10
Rotary kiln Rotary kilr,
with sec- with sec-
ondary ondary
combustor combustoi
EPA Waste identification no.
Incinerator ash quench
D001
F001
F002
F003
F005
X
D001 0001 None
D008 F001
F002
F003
F005
X X
0007
F001
F002
F003
F005
D001 D001
F003 F001
F005 F002
F003
F005
X
D001
D002
D006
D007
D008
D009
F001
F002
F003
F005
U002
X
(rotary kiln only)
0007
F001
F002
F003
FOOS
X
0007
F001
F002
F003
FOOS
X
(But no
ash during
testing)
Secondary combustion
chamber with liquid
waste injection
Hot-gas cyclones
Quench
Scrubber + demister
Acid absorbers
X
X
X
X
X
X
Waste heat recovery boiler X
(liquid-waste fired)
Wet ESP's
No control device
(Constraints on fuel and
firing rates)
Selective material reburning
X
X
X
X
X
X
X
X
X
X
X
X X
X X
X
X
(drums and
residue)
-------
Table 2. Summary of Samples Collected and Analyses Performed for 10 Hazardous Waste Incineration Facilities
Analyses
Stream description
Site numbers
Volatiles Semivolatiles
Priority
pollutant
metals
EPII
procedure
Draft
TCLP
PCB
identity3
Input Streams
APCE aqueous supply 8 X
Aqueous or low-Btu waste 1 and 5 X
Coating waste solids 7 X
Chloroprene catalyst sludge 2 X
CS tear gas powder 4 X
DCS coke solids 2 X
Drum feed liquids 3 X
Drum feed solids 3 and 9 X
Lacquer chips 6 X
Lacquered cardboard waste 5 X
Latex coagulum solids 7 X
Liquid injected waste fuels 1, 3, 5 to 10 X
PCB-contaminated dirt 1 X
PCB liquid waste 1 X
Unused automotive paint 2 X
Vacuum filter solids 2 X
Output Streams
APCE aqueous effluent 1 to 4, 7 to 10 X
Boiler tube soot blowdown 3 X
Cyclone ash 1 and 4 X
Incinerator bottom ash 5 to 8 X
Wastewater treatment facility belt
filter cake residue 3 and 7 X
Rotary kiln ash 1 to 3,8,9 X
Stack condensate 4
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
"Site 1 only.
APCE = Air polution control equipment
CS = O-chlorobenzalmalonitrile
DCS = 1,4-Dichlorobutene-2
complete combustion (PICs) (especially
possible with Site 4) or early ash
quenching before completed ash
burnout (possible with Sites 3 and 8).
Except for Site 4, where the feed mate-
rial was a relatively pure chemical, o-
chlorobenzalmalononitrile (CS), the
volatile organics found also appear in
the waste feed. The cyclone ash from
Site 4 shows several compounds that
appear to be PICs. Because the cyclone
ash was periodically emptied, and al-
lowed to fall freely during the cyclone
draining procedures, it was likely that
the volatiles observed were adsorbed
while the ash was in the cyclone and/or
during the free fall upon draining.
In general, most organic compounds
were detected at less than 10 ppm.
Since most sites quench ash with water,
especially if a rotary kiln discharges
solid waste feed too quickly, it is possi-
ble for some of the organics to not be
subjected to high enough temperatures
for complete destruction (thus, the ap-
pearance of the organics in the ash).
Also, the quench water is often recycled
plant wastewater which may experi-
ence a buildup of these organic com-
pounds and contaminate the ash (c.f.,
wet and dry ash from Site 8).
The total organic content in each ash
stream, calculated by adding the con-
centrations of all hazardous organic
compounds (RCRA, Appendix VIII) de-
tected, indicated that kiln and bottom
ash have similar semivolatile organic
content with average concentrations
measured approximately 100 mg/kg.
Average volatile organic content was
higher for the kiln ash. The bottom ash
average would be increased, however,
if values were deleted for Site 5's large
incinerator (since that incinerator
burned only liquid waste) and Site 8's
bottom ash (since that ash was predom-
inantly generated from liquid waste).
Average teachable volatiles and
semivolatile organics for each type of
ash were less than 1 mg/L or 1 ppm.
RCRA organics with the highest concen-
tration in the TCLP leachates were
toluene (1.7 ppm), phenol (1.8 ppm),
methylene chloride and dimethyl phtha-
late (each at about 0.6 ppm), and MEK
(0.3 ppm).
Volatile and semivolatile organics,
detected in various APCE effluents, indi-
cate that the highest concentrations of
volatile organics were in the APCE efflu-
ent at Site 5. Since the cyclone ash sam-
ple at this site also contained volatile
organics, these compounds may be at-
tributed to byproduct emissions from
the incinerator. Site 1 and 8 practice ex-
tensive water recirculation in compari-
son to the other sites which practice
only some APCE effluent recirculation
prior to discharge to an onsite waste-
water treatment facility. Because of this
higher recirculation, Site 1 and 8 APCE
effluents are expected to have higher
than average organic content in agree-
ment with results of this study.
Priority Pollutant Metals
Analytical results for metals concen-
trations in all ash residual samples are
-------
summarized in Table 3. Figures 1 and 2
show the ranges in total priority pollu-
tant metals experienced in ash and ash
leachate samples. The kiln ash indicates
an average priority pollutant metal con-
centration of about 1 percent (10,000
ppm). The same average is lower for the
bottom ash. Boiler ash from Site 3 has
the highest concentration of metals, as
indicated in Table 3. The small ash parti-
cle size at this site resulted in a high
surface-to-mass ratio which favors
metals condensation.
EP and TCLP metal analysis results il-
lustrated in Figure 1 indicate that
leachate concentrations are highest for
boiler ash. Kiln ash leachate would be
expected to have more metals than bot-
tom ash leachate, but one very low zinc
concentration apparently substantially
skewed the EP toxicity kiln ash data.
Table 4 shows the highest metals con-
centrations experienced in all leachate
test samples. EP leachate concentra-
tions are also compared with applicable
EP toxicity limits (standards set forth in
Table 4 of 40 CFR 261.24). The results
indicate that only 1 metals measure-
ment of the EP leachate, out of 84 meas-
urements performed for the whole
study, exceeded the maximum concen-
tration of contaminants for characteris-
tics of EP toxicity. Hence, only the boiler
ash at Site 3 (see Table 3), with a cad-
mium content of 8.6 mg/L versus an al-
lowable standard of 1 mg/L, would be
considered a hazardous waste for
metals not already listed in 40 CFR Sub-
part D. The TCLP leachate, if subjected
to the same standards, would have 3
measurements out of 84 exceeding an
allowable concentration. Site 3 boiler
ash would exceed the standards for cad-
mium at 6.7 mg/L, and selenium at 1.4
mg/L versus an allowable standard of
1 mg/L. Site 6 ash would exceed the
standard for lead at 12 mg/L versus an
allowable 5 mg/L. In general, the results
from the two different extraction proce-
dures were within a factor of three.
For leachate analysis, approximately
20 units of acidic water are used for
each unit of ash. Thus, leachate concen-
trations (in mg/L) are expected to be
about 20 times less than reported ash
values (in mg/kg) for 100 percent solu-
ble metals. Although several metals in
ash concentrations are at less than de-
tectable limits and cannot be further
evaluated, solubility generally ranged
from 1 to 10 percent. Metal concentra-
tions greater than 1000 mg/kg of ash,
included chromium (Site 3), copper
Table 3. Concentration of Priority Pollutant Metals in Incinerator Residuals
Site number
Stream
description
1
Kiln ash
2
Kiln ash
3
Kiln ash
3
Boiler ash
4
Cyclone ash
5
Large incinerator
bottom ash
Concentration'
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Tnsllium
Zinc
Comments
Wet or Dry Ash
Site number
Stream
description
(mg/kg)/ (mg/L) /(mg/L)
2 / <0.05 / 0.04
4 / 0.23 /<0.01
<1 / <0.01 /<0.01
<2 / <0.01 / <0.01
120 / 0.10 / 0.22
6900 / 8.6 1 16
220 / 2.3 / 3.5
<0.05/<0.001/<0.001
190 / 0.49 / 0.45
<1 /<0.05 / 0.02
11 /<0.01 /<0.01
160 / 0.14 / 0.42
Wet
5
Small incinerator
bottom ash
(mg/kg) / (mg/L) / (mg/L)
6 K0.01 /<0.01
2 / <0,01 / <0.01
<2 / <0.01 / <0.01
<1 / <0.01 / <0.01
110 / 0.09 / 0.10
840 / 3.7 / 7.9
100 / <0.01 / <0.01
1.5/<0.001/<0.001
7300 / 6.9 / 6
6 / 0.02 / 0.05
8 / 0.05 /<0.01
640/1.8/2
Wet
6
Incinerator
bottom ash
(mg/kg)
18
3
<7
<7
660
400
610
<0.1
240
13
4
•J
21000
Wet
/ (mg/L) /
/ 0.06 /
/ <0.01 /
/<0.01 /
/<0.01 I
/ 0.03 /
I 0.02 /
/ 0.04 /
KO.OOM
I 0.79 /
/ 0.17 /
1 0.02 /
/ 27 1
7
Incinerator
bottom ash
(mg/L)
<0.01
<0.01
<0.01
<0.01
0.06
0.09
<0.01
<0.001
13
1.4
0.05
<0 02
300
(mg/kg)/
190 /
14 /
6 I
61 /
1800 /
780 /
5000 /
0.2 /
4700 /
13 /
190 /
9 /
32000 /
Wet
(mg/L) /
<0.01 /
<0.01 /
<0.01 /
8.6 /
0.03 /
31 /
4.4 /
<0.001 /
20 /
<1 /
0.09 1
0 7^ /
1400 /
a
Kiln ash
(mg/L)
<0.01
<0.01
0.08
6.7
0.36
21
4.5
<0.001
13
1.4
0.05
<0 02
1200
(mg/kg)/ (mg/L) / (mg/L)
<1 /<0.01 /<0.01
< 1 / <0.07 /
-------
1000,000
10,000
1,000
100
Average
Legend
Kiln
Ash
Bottom
Ash
Boiler
Ash
Cyclone
Ash
Figure 1. Total and a verage priority pollutant metals concentrations in ash.
1,000
100
Wi
0 £/>///
v///////
A
i i
LJ
7
\\x\x\\\x\\xx
~u
^ Average
Legend
<
V///////////.
X
\
X
/
/
/
',
-
f-f^
••*
Kiln Bottom Boiler Cyclone
Ash Ash Ash Ash
Figure 2. Total and average metals concentrations in ash leachate.
(Sites 1, 7, and 8) lead (Sites 3, 5, 6, and
8), nickel (Sites 2 and 3), and zinc (Sites
3 and 8). Most of the leachate measure-
ments for antimony, arsenic, beryllium,
cadmium, lead, selenium, silver, and
thallium yielded values less than the de-
tectable limits nominal of 0.01 to 0.05
mg/L of leachate. Mercury leachate
measurements were all less than 0.001
mg/L of leachate.
These high concentrations in the ash
did not always yield a good mass bal-
ance. Most notably, the calculated dis-
charge rate for chromium (Site 3), cop-
per (Site 1), and lead (Site 6), exceeded
the calculated feedrate to the incinera-
tor by a factor of 10. Copper (Site 7)
showed a discharge rate 100 times the
feedrate accountable by the waste feed
samples. There are several possible rea-
sons for these results. First, process
data were not available for Site 5, and
all streams were not sampled for Sites 7
and 8; thus these mass balances cannot
be accurately made for those sites. In
general, to improve representativeness
of the samples, and to better close a
metals mass balance, would have re-
quired more sampling (and analysis) of
input and output streams over a longer
test period.
APCE water effluents were also ana-
lyzed for priority pollutant metals. The
results are summarized in Table 5. Two
sites which most effectively limit dis-
charging a wastewater effluent
(through high recirculation), Sites 1 and
8, have the highest concentration of
metals, 2,475 and 51 mg/L, respectively.
The wastewater effluents for these sites
were also found to contain higher than
average organic levels. A comparison of
these metals concentrations with EP
toxicity limits reveals that the Site 1 ef-
fluents would be considered toxic for
cadmium (3.5 mg/L), chromium (11 mg/
L), and lead (860 mg/L), while the efflu-
ent from Site 8 would be considered
hazardous for cadmium (2.8 mg/L), lead
(31 mg/L), and selenium (2.1 mg/L).
Sites with an apparent low effluent re-
circulation rate, such as Site 9, appear to
have low metals concentration in the
APCE effluent (2.3 mg/L).
Recommendations
On the basis of the data presented
above, Acurex recommends that more
sampling and analysis of hazardous
waste incinerator residues be under-
taken. Specifically, we recommend:
• Retesting, intermittently over a pe-
riod of perhaps 4 to 6 months, two
or three of the sites already tested.
-------
This will allow EPA to evaluate the
variations in residue quality over
time at one site.
• Testing incinerator sites which
have dry APCE systems in place.
Two of the sites already tested will
have their wet systems removed,
and dry systems installed. The "dry
sites" could also be new incinerator
facilities.
• Testing sites which typically burn
more chlorinated wastes,
• Testing some younger (in age) in-
cinerators and those with more
state-of-the-art equipment and con-
trols
• Testing enough new incinerator
sites to increase the data base to at
least 20.
Table 4.
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Highest Metals Concentrations
Toxicity
limit
5
—
1
5
—
5
0.2
1
5
—
in Ash Leachate in mg/L
EP
Concentration
0.49
0.23
<0.01
8.6
0.98
31
4.4
<0.001
20
0.17
0.09
0.05
1400
TCLP
Concentratic
0.36
0.54
0.08
6.7
0.36
21
12
<0.001
13
1.4
0.05
0.18
1200
References
1. Trenholm, A., P. Gorman, and
G. Jungclaus. Performance Evalua-
tion of Full-Scale Hazardous Waste
Incinerators. Midwest Research Insti-
tute, Kansas City, Missouri.
2. "Test Methods for Evaluating Solid-
Waste-Physical/Chemical Methods,"
SW 846 Second Edition, U.S. EPA,
April 1984.
3. "Toxicity Characteristic Leaching
Procedure (TCLP)," U.S. EPA draft re-
vised, December 20, 1985.
Table 5. Concentrations of Priority Pollutant Metals in APCE Aqueous Effluents, in mg/l
Site number 1234 78" 9 10
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Total
0.1
0.2
<0.01
3.5
11
550
860
0.06
<0.02
0.09
<0.01
<0.01
950
2380
<0.01
<0.01
<0.01
<0.01
<0.05
<0.04
<0.01
0.013
23
<0.01
<0.02
1.3
0.02
24.3
0.61
<0.01
<0.01
0.04
0.1
0.26
2.6
0.013
0.17
<0.01
0.04
16
16
35.7
<0.01
<0.01
<0.01
<0.01
0.06
<0.04
<0.01
<0.001
0.05
<0.01
<0.02
0.02
0.27
0.4
1.7
0.06
<0.01
0.08
0.28
0.64
2.6
<0.005
0.75
0.6
0.05
0.16
6.7
13.6
4.1
0.4
0.01
2.8
3.8
2.2
31
<0.005
1.5
2.1
0.15
1.6
1.6
51.3
<0.03
<0.1
<0.01
<0.01
0.27
0.46
0.38
<0.005
0.07
<0.1
0.61
0.31
0.16
2.26
0.1,
<0.1
<0.0
<0.0
0.2
0.0
0.1
<0.0
0.4
0.2
<0.0
0.0
0.1
1.3
'Highest values used for aqueous effluent recirculated from two cooling ponds.
Donald VanBuren, GaryPoe. and Carlo Castaldini are withAcurex Corporation,
Mountain View, CA 94039.
Paul Warner is the EPA Project Officer (see below).
The complete report, entitled "Characterization of Hazardous Waste Incineration
Residuals,"(Order No. PB 87-168 159/AS; Cost: $18.95, 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:
Hazardous Waste Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
-------
-------
United States Center for Environmental Research
Environmental Protection Information
Agency Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-87/017
0000329 PS
60604
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