United States
Environmental Protection
Agency
EPA/540/F-95/510
August 1995
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Emerging Technology Bulletin
Two-Zone PCE Bioremediation System
ABB Environmental Services, Inc.
U.S. Environmental Protection Agency
Technological Description: ABB Environmental Services, Inc.'s
(ABB-ES), research has demonstrated that sequential anaerobic/
aerobic biodegradation of tetrachloroethylene (PCE) is feasible if
the proper conditions can be established. The anaerobic process
can potentially completely dechlorinate PCE. However, conver-
sion of vinyl chloride (VC) to ethylene is the slowest step in this
process. Of the chlorinated ethenes, VC is the most amenable to
treatment by aerobic methanotrophic processes. Therefore, a
two-step process is thought to be the most efficient. The first
step is anaerobic, which rapidly dechlorinates PCE and trichloro-
ethylene (TCE) to breakdown products 1,2-dichloroethylene (DCE)
and VC. Since the anaerobic dechlorination of DCE and VC to
ethylene can be quite slow, a second aerobic step is imple-
mented that can more quickly complete the remediation process.
The schematic diagram below illustrates this technology.
The goal of this project is to field test the effectiveness of creating
and maintaining the proper insitu conditions for chlorinated ethene
degradation in an aquifer. To achieve this goal, ABB-ES will test
methods of carbon and mineral nutrient injection and delivery into
an aquifer contaminated with PCE or TCE. Groundwater chemi-
cal conditions will be monitored within and downgradient of the
anaerobic treatment zone to gauge the efficiency of the anaero-
bic process. If volatile organic compound analyses show thai: the
resulting downgradient breakdown products include TCE, DCE,
or VC, oxygen and methane will be added to the groundwater to
stimulate aerobic degradation by indigenous methanotrophic bac-
teria.
Waste Applicability: This technology removes PCE, TCE, DCE,
and VC from groundwater.
An Emerging Technology Summary on the bench-scale testing
results will be available from EPA in late 1995.
SAMPLING PORT
AEROBIC
'SOIL COLUMN
REDUCED
MEDIUM
SAMPLING PORT
PCE
DNAPL
Figure 1. Sequential anaerobic/aerobic treatment.
Printed on Recycled Paper
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For Further Information:
EPA Project Manager:
Ronald Lewis
U.S. EPA
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7856
Fax: 513-569-7620
United States
Environmental Protection Agency
National Risk Management Research Laboratory (G-72)
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/540/F-95/510
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