United States
Environmental Protection
Agency
EPA/600/M-90/014
September 1990
incineration
research facility
I R F Bulletin
Rotary Kiln Incineration of
Metal/Pesticide Soil from Baird
and McGuire Site in Region I
Can incineration be employed as a
remediation technology for a
Superfund site if the soil contains
both organics and metals? This was
the question recently asked by EPA
Region I and ORD's Risk Reduction
Engineering Laboratory (RREL). To
answer, a pilot scale incineration test
that simulated full-scale, onsite
thermal treatment was conducted.
The capabilities of ORD's Incineration
Research Facility (IRF) in Jefferson,
Arkansas, were used to conduct the
test, analyze the samples, evaluate
the data, and prepare a report of
findings.
The site in question was the Baird and
McGuire pesticide batching and mixing
operation in Holbrook, Massachusetts
The site has a significant number of
pesticides in the soil that range in
concentrations up to 1500 ppm. In
addition to the pesticides, lead and
arsenic were found throughout the site at
concentrations generally below 100 ppm,
but with hot spots for arsenic as high as
3800 ppm. It has been well documented
in the literature that pesticides can be
effectively treated by incineration.
Therefore, the main focus of the test was
to evaluate the fate of the metal
contaminants and to confirm that
pesticides are adequately destroyed by
thermal treatment in this particular soil
matrix. RREL's past research on metals
partitioning during incineration indicated
that arsenic was not as volatile as thought
and under some combustion conditions a
significant fraction would remain in the
ash. If this held true for the Baird and
McGuire soil matrix, incineration might be
employed as the remediation technology
with minimal air pollution effects.
Pilot scale experiments, using the
RREL hardware shown in Figure I, were
planned around an operating envelope of
temperature and excess air The
partitioning of the metals in the Baird and
McGuire soil would be studied at the
nominal conditions of 1500°/1800°F kiln
temperature and 6%/10% kiln exit
oxygen concentration. A test series of 5
experiments was conducted in the early
fall of 1989 with 1529°F/11.3% 02,
1552°F/6.8% 02, 1822°F/10.4% 02, and
1822°F/7.5% 02 being the actual
conditions and 1541°F/11.2% 02 being a
duplicate of the 1st test condition. The
results are summarized in Table 1 and
illustrated in Figures 2 and 3 for arsenic
and lead, respectively The incineration
of the Baird and McGuire soil indicated
that
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Figure 1. Schematic of the Rotary Kiln System.
Table 1. Metal Discharge Distribution for the Ba/rd and McGuire Incineration Tests (Weight
Percent)
15234
Test
Kiln exit temperature, °F
Kiln exit O2, %
Arsenic
Kiln ash
Scrubber liquor
Scrubber exit flue gas
Total
Lead
Kiln ash
Scrubber liquor
Scrubber exit flue gas
Total
(9-26-89)
1529
11.3
59
19
4
82
100
5
8
113
(10-5-89)
1541
11.2
49
21
4
74
90
3
5
98
(9-29-89)
1552
6.8
77
22
2
101
138
4
6
148
(9-27-89)
1822
10.4
22
34
6
62
25
5
7
37
(9-28-89)
1822
7.5
43
30
5
78
35
7
9
51
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Kiln Oxygen 7%
% of Metal Fed
80-i
60-
Kiln Ash
SE flue gas
Liquor
% of Metal Fed
80 -i
Kiln Ash
Kiln Oxygen 11%
SE flue gas
Liquor
Figure 2. Arsenic distribution: temperature effects.
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% of Metal Fed
Kiln Oxygen 7%
Kiln ash
SE flue gas
Liquor
% of Metal Fed
Kiln Oxygen 11%
Kiln ash
SE flue gas
Liquor
Figure 3. Lead distribution: temperature effects.
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- As the kiln temperature increased
from 1500T to 1800°F, the amount
of arsenic and lead partitioning
(remaining) in the ash decreased and
the amount found in the flue gas and
scrubber water increased (whether
this was metal volatilization or
increased particulate carry out isn't
known for sure, but ash carry over is
suspected).
- As the oxygen concentration
increased from the nominal values of
6% to 10%, the arsenic and lead
partitioning (remaining) in the ash
decreased.
- All of the pesticides in the flue gas
were reduced to nondetectable at 20
ng per sample train.
There are two aspects to the metals
release problem associated with
incineration. The first is the air pollution
concerns and they were addressed by
the information presented above. The
second phase of the metals problem
revolves around the teachability of the
metals from the ash. To address this
concern, TCLP samples were taken on all
the ash samples and analyzed for arsenic
and lead. The TCLP data for arsenic and
lead is summarized in Table 2 along with
the other emission data and shows that:
- As the temperature is increased from
1500°F to 1800°F at constant
nominal kiln exit oxygen concen-
tration, the TCLP for arsenic
remained relatively constant (i.e.,
values changed from 0.33 and 0 24
mg/L to 0.22 mg/L at a nominal 10%
oxygen and they changed from 1.17
mg/L to 1.24 mg/L at a nominal 6%
oxygen).
- As the oxygen in the kiln exit was
increased from nominal 6% to 10%
at constant nominal temperature, the
arsenic TCLP was significantly
reduced (i.e., values changed from
1.17 mg/L to 0.33 and 0.24 mg/L at a
nominal 1500°F temperature and
from 1.24 mg/L to 0.22 mg/L at a
nominal 1800°F).
- The lead TCLP was not significantly
affected by either of the variables as
it was below detection limits of .05
mg/L in all cases.
After all the tests were completed and
he samples analyzed, what can be said
ibout the incinerability characteristics of
he Baird and McGuire soil?
- Low temperature incineration
(1500°F) with elevated excess
oxygen in the kiln (10%) produced
an ash that retained high levels of
arsenic and lead.
- Kiln ash
leachable.
lead was not TCLP
- Kiln ash arsenic was leachable, its
mobility increased as the
temperature was increased, and as
the kiln excess oxygen decreased.
- Even though the arsenic was
leachable from the ash, none of the
samples exceeded the TCLP
regulatory level of 5 mg/L.
- All the pesticide emissions were
reduced to nondetectable.
- Incineration of this soil did not create
a particulate control problem as all
particulate emissions were 29
mg/dscm or lower
The general consensus of both ORD
and Region I was that the test generated
useful data on the Baird and McGuire soil
that will be used m the design phase of
the site cleanup Incineration conditions
of low temperature and high excess kiln
oxygen would be the best for retaining
arsenic in the soil. This treatability study
took six months to complete (project
design, analysis, and report preparation)
and was substantially funded by the
Region. Paula Fitzsimmons, USEPA,
Region I, is the RPM for Baird and
McGuire and coordinated this incineration
test with RREL. Additional technical
information on the test or use of the IRF
for other tests should be directed to:
Robert C. Thurnau
U.S. Environmental Protection
Agency
26 W. Martin Luther King Drive
Cincinnati, OH 45268
513/569-7692.
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Table 2. Arsenic and Lead Concentration in Test Samples
Test
(9-26-89)
2
(9-29-89)
3
(9-27-89)
4
(9-28-89)
5
(10-5-89)
Kiln exit temperature, °F
Kiln exit O2, %
1529
11.3
1552
6.8
1822
10.4
1822
7.5
1541
11.2
Arsenic concentrations
Soil feed (mg/kg) 32 83 93 81 84
Soil TCLP leachate (mg/L) rj.091 °-°" °-114 °-116 °-102
Kiln ash (mg/kg) 71 85 33 40 58
Kiln ash TCLP leachate (mg/L) 0.33 1-17 °-22 1-24 °-24
Scrubber blowdown (mg/L) 1.5 1.9 2.9 2.4 2.0
IWS exit flue gas (mg/dscm) 0.107 0.088 0.171 0.136 0.102
Lead concentrations
Soil feed (mg/kg) 21 16 27 17 20
Soil TCLP leachate (mg/L) <0.05 <0.05 <0.05 <0.05 <0.05
Kiln ash (mg/kg) 3-1 30 11 7 26
Kiln ash TCLP leachate (mg/L) <0.05 <0.05 <0.05 <0.05 <0.05
Scrubber blowdown (mg/L) g rjg 0.07 0.11 0.11 0.08
IWS exit flue gas (mg/dscm) 0.053 0.045 0.061 0.050 0.037
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