United States
Environmental Protection
Agency
EPA/540/F-94/502
April 1994
&EPA
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Emerging Technology Bulletin
Photolysis/Biodegradation of PCB and PCDD/PCDF Contaminated Soils
i
IT Corporation
Technology Description: This process is a two-stage pho-
tolytic and biological soil detoxification process that has applica-
tion to treatment of soils contaminated with polychlorinated
biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).
The process may be used in-situ for treatment of shallow soil
contamination or as an ex-situ, on-site treatment for excavated
soils.
The first step in the process is to degrade the organic contami-
nants by using ultraviolet (UV) radiation. The source of the UV
radiation may be either artificial UV light or natural sunlight.
Alternatively, advanced oxidation processes such as iron cata-
lyzed hydrogen peroxide (Fenton's Reagent) may be used to
provide primary contaminant degradation. Both photolysis and
chemical oxidation are expected to convert contaminants to more
biodegradable compounds. Biological degradation, the second
step, is then used to further degrade organic contaminants.
Biodegradation is enhanced by the addition of microorganisms
and nutrients to the UV treated soil. Residues from the process
are surfactants and the end metabolites of the biodegradation
process.
Waste Applicability: The IT Corporation photolysis/ biodegra-
dation process is designed to destroy organics, particularly 2,3,7,8-.
Table 1. Summary of UV Photolysis Results on PCB Contaminated Soil
tetrachlorodibenzo-p-dioxin (TCDD) and polychlorinated biphe-
nyls (PCBs), other polychlorinated organics and polynuclear aro-
matic hydrocarbons in soils.
j
Test Results: Bench-scale UV photolysis testing was performed
on ttiree soils; one containing 200-300 ppb 2,3,7,8,-TCDD and
two containing 200-10,000 ppm aroclor 1248 PCB contamination.
Tests were conducted independently using a medium pressure
mercury lamp, or a 10 Hertz (Hz) pulsed lamp and sunlight,
employing surfactants at 0 to 5% of the weight of the dry soil.
Resijlts of the PCB experiments are summarized in Table 1.
Tests; performed on TCDD contaminated soils showed no signifi-
cant Apparent destruction of dioxin.
Additional testing was conducted using Fenton's reagent chemis-
try as an alternate method of degrading PCBs to more easily
biodegraded compounds. Experiments on soil contaminated with
5000J-10,000 ppm PCBs (arochlor 1248) were performed. PCB
destruction ranged from <15 to 55%.
The ability of selected organisms to biotransform PCB congeners
in surfactant/UV treated and untreated soils was evaluated during
two bioslurry treatment experiments. The first bioslurry treatment
experiment evaluated the biological reduction of PCB congeners
Test
1
2
3
4
5
6
7
8
9
10
11
Condition
Surface soil, pulsed lamp, 0.25 inch soil depth, 2% surfactant, 25°C
Surface soil, medium pressure Hg lamp, 0.25 inch soil depth, 2% surfa
Surface soil, medium pressure Hg lamp, 0.25 inch soil depth, 2% surfa
Pit soil, medium pressure Hg lamp, 0.5 inch soil depth, 2% surfactant,
Pit soil, pulsed lamp, 0.5 inch soil depth, 2% surfactant, 28°C
Pit soil, pulsed lamp, 0.5 inch soil depth, 2% surfactant, 28°C
Pit soil, solar irradiation, 1.0 inch soil depth, 4.5% surfactant, 30-40"C
Pit soil, solar irradiation, 1.0 inch soil depth, 2% surfactant, 30-40"C
ctant, 28°C
ctant, 40°C
30"C
Pit soil, solar irradiation, 1.0 inch soil depth, 0% surfactant, 30-40°C I
Fine ground surface soil, med. Hg lamp, 0.25 inch soil depth, 2.5% surfactant
Fine ground surface soil, med: Hg lamp, 0.25 inch soil depth, 2.5% surfactant
Time
(Hours)
12
7
7
16
16
12
25 days
25 days
25 days
20
20
Initial PCB
Cone, (ppm)
7240
7430
8440
140
157
170
132
159
171
wooo -•
10000
Final PCB %
Reduction
<15
<15
33
30
13
23
<15
<15 '
<15 .
52"
32
'Increase in concentration noted for di-PCBs, decrease in concentration for tetra through hepta-PCBs.
Printed on Recycled Paper
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In surfactant/UV-treated and untreated soils. A subsequent en-
hanced bfoslurry treatment evaluated the impact of PCB-biodeg-
radation inducars on congener removal. Bioslurry experiments
Were conducted under aerobic conditions at 25"C. PCB reduc-
tions lessened with increasing level of chlorination with no signifi-
cant reduction of penta, hexa, and hepta-PCBs. Similar reductions
were obtained with inducer additfons to the soil.
. [
Although the percent of PCB degradation was low, meaningful
destruction may have been masked by the high concentration of
PCBs in the surface soil that was used in many of these tests.
Also, high amounts of surfactant were carried through the treat-
ment process and may have been inhibitory to bacterial activity as
evidenced by the high total organic carbon and tow pH of the soil.
For Further Information:
EPA Project Manager:
Randy Parker
U.S. EPA Risk Reduction Engineering Laboratory
26 West Martin Luther King Dr.
Cincinnati, OH 45268
513-569-7271
Fax:513-569-7620
Technology Developer Contact:
Ed Alperin
IT Corporation
312 Directors Drive
Knoxville, TN 37923
615-690-3211
Fax:615-694-9573 'U.S. Government Printing Office: 1994 — 550-067/80255
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
EPA/540/F-94/502
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
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