United States
Environmental Protection
Agency
EPA/540/F-94/504
May 1994
&EPA
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Emerging Technology Bulletin
Institute of Gas Technology
(Chemical and Biological Treatment)
Technology Description: The institute of Gas Technology's
(IGT) Chemical and Biological Treatment (CBT) process
remediates sludges and soils contaminated with organic pollut-
ants, such as polyaromatic hydrocarbons (PAHs) and polychlori-
nated biphenyls (PCBs). The treatment system combines two
remedial techniques: (1) chemical oxidation as pretreatment, and
(2) biological treatment using aerobic and anaerobic biosystems
either in sequence or alone, depending on the waste. The CBT
process uses mild chemical treatment to produce intermediates
that are biologically degraded, reducing both the cost and risk
associated with more severe treatment process, such as incin-
eration.
The figure below shows some of the options available for applica-
tion. The contaminated material is treated with a chemical re-
agent that degrades the organopollutants to carbon dioxide, water,
and more biodegradable partially-oxidized intermediates. In the
second stage of the CBT process, biological systems are used to
degrade the hazardous residual materials and the partially-oxi-
dized material from the first stage. Chemically-treated wastes
are subject to cycles of aerobic and anaerobic degradation if
aerobic or anaerobic treatment alone is not sufficient. Also, sev-
eral cycles of chemical and biological treatment are used for
extremely recalcitrant contaminates.
Waste Applicability: The CBT process can be applied to soils
and sludges containing high waste concentrations that would
For TCE, PAHs
\
CO, CH4 C02
t T
Aerobic
^
Anaerobic
Clean
— — 1,,
product
Contaminated
soil/sludge
Chemical
oxidation
,
AriMroijic
!
w
Aerobic
r I
CH4 CO2 C02
Cleat
product
Figure l Chemical and biological treatment (CBT Process).
typically inhibit bioremediation and low waste concentrations when
bioremediation alone is too slow. The process is not adversely
affected by radionuclides or heavy metals. Depending on the
types of heavy metals present, these metals will either
bioaccumulate in the biomass, complex with organic or inorganic
material in the soil slurries, or solubilize in the recycled water.
The CBT process can be applied to a wide range of organic
pollutants, including alkenes, chlorinated alkenes, aromatics, sub-
stituted aromatics, and complex aromatics. Applicable matrices
include soil, sludge, groundwater, and surface water.
Test Results: IGT has completed two yr of evaluation of the
CBT process within the SITE Emerging Technology Program.
This evaluation has included bench-scale studies of important
operational parameters for applying the CBT technology to soils
and sludges contaminated with PCBs. Table 1 shows the PCS
degradation for a single-cycle of the chemical/biological treat-
ment process. Results indicate that this technology can treat
various PCB-contaminated matrices with modifications to the
original treatment protocol that increases the availability of the
PCBs.
During the evaluation of the CBT process, a nonstandard GC/
ECD method for PCS analyses was developed at IGT for quanti-
fication of individual PCS congeners. Although there are several
EPA methods for analyses of PCBs, no method is currently
approved for quantitative analyses of PCBs which have been
chemically altered by chemical, biological, or thermal reaction.
Protocol development and verification was necessary before be-
ginning experiments with PCS contaminated soils.
Initial studies indicated that 30-40% of 2,2',4,4' tetrachlorinated-
14C—biphenyl could be mineralized to 14CO2 by chemical oxida-
tion. Equally as important, 30-35% of 2,2',4,4'
tetrachlorinated-biphenyl is modified to a water soluble, more
easily degradable product. As expected the higher the chlorina-
tion of the biphenyl, the lower the amount of mineralization.
Chlorine groups in the 3-position inhibited mineralization by 50%
when compared with the 2-position. Chlorines in the 4-position
appear to be sightly more susceptible (=8%) to chemical degra-
dation than chlorines in the 2-position. This difference is statisti-
cally significant as measured by ± the standard deviation. This
study indicated that the majority of the chemical mineralization of
PCBs occurs in the first 45-60 min of the reaction.
The standard reagent concentration of 2.5% H2O2 and ferrous
sulfate, 10mM, resulted in the greatest degradation in both the
Printed on Recycled Paper
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Table 1. PCS Degradation by IGTs Chemical and Biological Treatment
Process
Single-Cycle
Treatment*
Biological
(Aerobic)
Water
30%
Sludge
<5%
Soil
0%
Chemical
Chemical/
Biological
(Aerobic)
90%
100%
65%
65%
50%
30%
. Chemical Treatment = 5% H2O2 for 1 hr.
Biological (Aerobic) Treatment = 10% inoculum of a mixed
consortium for approximately 15 Days
lower and higher chlorinated compounds. When compared to the
control, 40% of total PCBs were removed by chemical degrada-
tion and as much as 90% of some PCB congeners were removed.
As the reagent concentration increases the degradation of PCBs
increases; however, the PCBs with less than 5 chlorine groups
are more susceptible than PCBs with greater than 5 chlorine
groups. This pattern complements the anaerobic and aerobic
biodegradation of PCBs in that it aggressively attacks the interme-
diate biphenyl compounds with 3-5 chlorine groups, anaerobic
biodegradation effectively reduces the concentration of higher
chlorinated biphenyls (4-8 chlorine groups) by 44-70% and aero-
bic biodegradation efficiently removes mono- and di-chlorinated
biphenyls. Experiments conducted using actual contaminated soil
demonstrated greater than 50% of all congeners were removed
with a single cycle of the integrated chemical/biological degrada-
tion.
IGT's CBT technology continues to be successfully applied to
PAH-contaminated soils. The CBT process consistently outper-
forms conventional bioremediation, especially with multi-ring
(4-6) PAH compounds. The CBT process increases both the
rate and extent of removal of contamination from various types of
soils. Two successful field tests, one solid-phase land treatment
and one in the soil slurry mode, have been conducted under
other gas industry supported programs. The field experiment
showed that the integrated treatment system resulted in about
50% greater removal of total PAHs and 90% greater removal of
carcinogenic PAHs than those of conventional biotreatment. The
integrated system's results exceed the treatment goals which
had been established and were reached in 42 days. This field
study verified the effectiveness of the integrated biological-chemi-
cal treatment process on a large- scale demonstration. Also, the
field data show that the integrated process results in higher
cleanup levels and at faster rates as compared with biological
treatment alone.
The CBT technology has been admitted into the SITE Demon-
stration Program and IGT is evaluating possible sites for a full-
scale demonstration.
For Further Information:
EPA Project Manager . -L__._li_J,___1_j
Naomi Berkley
U.S. EPA
Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7854
Technology Developer Contact:
Robert Kelley
Institute of Gas Technology
3424 South State Street
Chicago, IL 60616-3896
312-949-3809
Fax: 312-949-3700
'U.S. Government Priming Office: 1994 -550-067/80250
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
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EPA
PERMIT No. G-35
EPA/540/F-94/504
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