United States
Environmental Protection
Agency
Office of Research and
Development
Washington, DC 20460
Office of Solid Waste and
Emergency Response
Washington, DC 20460
&EPA
SITE FACTS
c Location: St. Louis Park, >
Minnesota x \'/
Laboratories/Agencies: U.S.
"• EPANationalRiskManagement
and Research Laboratory /
- (NRMRL), Superfundfanovalive
" Technology Evaluation (SITE) -
^ProgranvIIS. EPARegk«a5,
s Minnesota PolutionControl ,
s Agency ^ « ,
Media and Contaminants:
. Polycyclic aromatic
hydrocarbons (PAHs) in soil
-Treatment: Bioventing
V
Date of Initiative Selection:
October 1992 -,V ~~
Objective: To evaluate ttie >
effectiveness of bioventing
PAH-contaminated sojl
Bioremediation Field Initiative
Contacts: PaulMcCauleyTand '
Richard Brenrter, U.S. EPA
NEMRL, 26 West Martin _^
Luther B3ng Drive, Cincinnati,
OH 45268 - -
I "• * x "" 4 "
- Regional Contact: Daryl
Owens, LT S. EPAReg^on 5,
Waste Management Division,
77 West Jackson Boulevard,
Chicago, IL 60604
EPA/540/F-95/506H
September 1995
Bioremediation Field
Initiative Site Profile:
Reilly Tar and Chemical
Corporation Superfund Site
Background
This Bioremediation Field Initiative project is tinder way in St. Louis
Park, Minnesota, at the former site of Reilly Tar and Chemical Corpo-
ration's coal tar distillation and wood preserving plant. From 1917 to
1972, wastewater discharges and dumping from this plant contami-
nated about 80 acres of soil and the underlying ground water with
wood preserving wastes. In 1978, the Minnesota Department of
Health discovered significant concentrations of polycyclic aromatic
hydrocarbons (PAHs) in six municipal drinking water wells neigh-
boring the Reilly Tar plant. St. Louis Park currently is pumping and
treating the contaminated ground water plume, but without an effort
to control the source of PAHs, pumping and treating might be neces-
sary for several hundred years.
This Initiative project is evaluating bioventing of PAH-contaminated
soil through the U.S. EPA Superfund Innovative Technology Evalu-
ation (SITE) Program and the U.S. EPA National Risk Management
Research Laboratory's (NRMRL) Biosystems Program. Bioventing
has proven effective at remediating lightweight petroleum distillates
such as JP-4 jet-fuel; this is the first evaluation of bioventing's effec-
tiveness for remediation of larger molecular weight hydrocarbons.
Characterization
-sf •
The SITE program conducted a preliminary site characterization,
including soil sampling, soil gas monitoring, and in situ respiration
testing, in August 1992. Soil sampling revealed PAH contamination
in sandy vadose soil ranging from 3 to 10 ft below the surface. Soil
gas monitoring and respiration tests indicated that the soil's aerobic
microbial activity and air permeability are high enough for success-
ful bioventing.
Field Evaluation
In November, 1992, baseline soil sampling was conducted and a
full-scale bioventing system installed on a 50-ft by 50-ft plot (see
Figure 1). A control plot of equal size and contaminant levels also
was establishe^ to gauge the effectiveness of the bioventing system.
The system consists of one air injection well with screening 5 to 10
ft below ground level (see Figure 2), a 2.5-hp blower, a network of
Recycled/Recyclable
Printed on paper that contains at
least 20 percent recycled fiber
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Delineated Plot Boundary-
Pressure Gauge
- 50-00'
Gl - Gas Injection Vent
GS - Gas Sample Probes
T - Temperature Probes
WL-Water Level Well
PVC Pipe
2" OD, Schedule 40
Sand Pack
Screened
Section
Figure 1. Layout of bioventing installation on experimental plot. Figure 2. Schematic of air injection vent well.
54soilgassamplingprobes, and a system to moni-
tor soil temperature and ground-water elevation.
The blower and vent well deliver 100 ft3 of air per
hour to the contaminated soil.
Personnel from the City of St Louis Park inspect
the site for malfunctions every 2 weeks. In situ
respiration tests are being conducted four times per
year by NRMRL. At the completion of the project,
final soil samples will be collected from the experi-
mental and the control plots.
Status
Quarterly shut-down respiration tests over the first
2 years have ranged from below detection to 0.48
percent Oa/hr. The highest respiration rates were
found in the western half of the treatment area
where PAH contamination was also the heaviest.
Current average measured respiration rates are
consistent with a 14 percent reduction in PAH con-
tamination per year. After 2 years bioventing, 70
soil borings were taken from a 25-ft x 25-ft section
in title northwest corner of the test plot. PAH analysis
of these soil borings was statistically inconclusive.
The demonstration project is expected to last 3
years, at which point it is estimated that soil core
samples must show at least a 27 percent reduction
in PAH levels to be statistically significant. If
bioventing successfully biodegrades PAHs at this
rate, complete bioremediation of the site would
take 10 to 15 years if large-scale bioventing is un-
dertaken. The results of this study will help deter-
mine whether bioventing can be considered at
Superfund sites as a cost-effective treatment for
remediating PAH-contaminated soils.
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TJicBioremediationFieldlnitiattve was establishedin 1990 to expand the nation's field experience in bioremediation technologies/"
The Initiative's objectives are to more fully document the performance of full-scale applications of bioremediation; provide
technical assistance to regional and state site managers; and provide information on treatability studies, design) and operation of*
bioremediation projects.The Initiative currently is performing field evaluations of bioremediation at eight other hazardous waste
sites: Libby Ground Water Superfund site, Libby, MT; Park City Pipeline, Park City, KS; Bendix Corporation/Allied Automotive l
Superfund site, St. Joseph, MI; West KL Avenue Landfill Superfund site, Kalamazoo, MI; Eielson Air Force Base Superfund site,
Fairbanks, AK; Hill Air Force Base Superfund site. Salt Lake City, UT; Escambia Wood Preserving Site, Brookhaven, MS; and Public
Service Company, Denver^ CO. To obtain profiles on these additional sites or to be added to the Initiative's mailing list, call
513-569-7562, For further information on the Bioremediation Field Initiative, contact Fran Kremer, Coordinator, Bioremediation
Field Initiative, VS. EPA, Office of Research and Development, 26 West Martin Luther King Drive7Ciricinnati, OH 45268; or,Michadf
Forlini, U.S. EPA, Technology Innovation Office, Off ice of Solid Waste and Emergency Response, 401 M Street, SW., Washington,'
DC20460. " .••••:'''.'' *- M*.
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