U.S. Environmental
Protection Agency
Office of Solid Waste and
Emergency Response
Technology Innovation Office
EPA/540//M-91/002 No. 5 May 1991
The applied technologies journal for Superfund removals and remedial actions and RCRA corrective actions
Nitrate Enhanced Bioremediation Restores
Fuel Contaminated Groundwater to
Drinking Water Standard
by John Wilson, Robert S. Kerr Environmental Research Laboratory
N
Jet fuel
Bioremediation
Groundwater
itrate enhanced bioremediation
restored a jet fuel contaminated aquifer to
drinking water standard levels within 165
days. This field demonstration, at the U.S.
Coast Guard Facility at Traverse City, Ml,
repeated and validated a remediation
conducted in the Upper Rhine Valley in
Germany more than ten years ago. To the
author's knowledge, nitrate enhanced
bioremediation has been used at only one
other fuel contaminated site in the United
States, One factor constraining the use of
nitrate bioremediation is that nitrate in
groundwater is subject to a drinking water
standard. Yet, nitrate presents a viable
treatment alternative to, oxygen enhanced
bioremediation. Although oxygen has
been effective for many fuel spills, success
is sometimes limited due to the low
solubility of oxygen. Nitrate is more
soluble than oxygen and is less expen-
sive. The significance of the nitrate
bioremediation at Traverse City is that
the concentration of nitrate used in the
bioremediation was below Federal
drinking water standards.
At Traverse City, jet fuel contain-
ing benzene, toluene, ethylbenzene and
xylene compounds had leaked from
underground storage facilities. The fuel
contaminated both the unsaturated soils
and the aquifer. For this reason, it was
necessary to install an infiltration
gallery system as the first stage of
bioremediation prior to the addition of
the nitrate. The infiltration gallery
system, using pumped aquifer ground-
water, saturated the unsaturated zone so
that when nitrate and nutrients were
added, they could be evenly distributed
In order to determine the effects of
dilution of the contaminants in the
recirculated groundwater and the effects of
natural bioremediation, nitrate and
nutrients were not added for six weeks.
Prior to the addition of the nitrate, the area
was sampled to evaluate what
biorestoration had occurred without nitrate
enhancement. This analysis found that
indigenous ambient concentrations of
oxygen and nitrate had removed benzene
to below 0.1 |4g/L, from initial concentra-
tions of 760 ng/L. The other contaminants
required artificially induced nitrate
additions to achieve acceptable levels.
(see Jet Fuel, page 2)
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•Fire at Tech Trends are glad to fell
yea what we know to be available m
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ive can spread &e good word.
If you have something you feel we
should know about, contact the
Editor of Tech Trends at
703-525-0485,
Technologies lor Source Control
at Superfund Sites
Available
Technologies (63%)
Q Solidification/Stabilization
D On-Site Incineration
5 Off-Site Incineration
Innovative
Technologies (37%)
B Soil Washing
•J Chemical Extraction
0 Bioremediation
Sin Situ Soil Flushing
Vacuum/Vapor Extraction
U In Situ Vitrification
B Chemical Treatment
• Thermal Desorption
Data are derived from 1982-1989 Records eff Decision
Printed on Recycled Paper
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SITE Subjects
Debris Washing
System Removes
PCBs, Herbicides
by Naomi P. Barkley,
Risk Reduction Engineering Laboratory
PCBs
Debris-
washing
system
Soil and debris
r\ rugged, transportable debris
washing system (DWS) has success-
fully removed polychlorinated biphe-
nyls (PCBs) from transformers at the
Gray Superfund Site in Hopkinsville,
KY, and herbicides and benzonitrile
from drums at the Shaver's Farm Site
in Chickamauga, GA. The DWS, an
EPA-developed technology, was
demonstrated as part of EEA's Super-
fund Innovative Technology Evaluation
(SITE) program. The DWS may have
broad applicability for other sites that
contain toxic organic and inorganic
chemical residues intermingled with
remnants of razed structures (wood
steel, concrete blocks, bricks) as well as
contaminated soil, gravel, concrete and
metallic debris (e.g., machinery and
equipment, transformer casings and
miscellaneous scrap metal). The DWS
was developed to decontaminate
material so that it can be considered
"clean" fill for disposal (either on site
or off site) as a nonhazardous waste
rather than a hazardous waste. Metallic
debris can be sold to a metal smelter.
The DWS entails the application
of an aqueous solution during a high
pressure spray cycle, followed by
turbulent wash and rinse cycles. An
aqueous rather than organic cleaning
solution was used because organic
solvents tend to be more costly and am
more difficult to handle than aqueous
cleaning solutions. The pilot-scale
system consists of a 300 gallon spray
tank, a 300 gallon wash tank, a
surfactant holding tank, a rinse water
holding tank, an oil/water separator and
a solution treatment system with a
diatomaceous earth filter, an activated carbon
column and an ion exchange column.
Ancillary equipment includes a spray tank
heater, pumps, particutate filters, a metal
basket and a stirrer motor.
At the Gray Superfund Site, soil was
contaminated with lead and PCBs from a
metal reclaiming operation that involved
open burning of electrical transformers.
Before the DWS cleaning process began, 75
transformer casings were cut in half with a
partner saw and the pieces were wiped to
provide samples of pretreatment PCB
concentrations. The transformer halves were
placed in the wash basket and lowered into
the spray tank that was equipped with
multiple water jets that blast loosely adhered
contaminants and dirt from the debris. After
the spray cycle, the basket was removed and
transferred to the wash tank, where the debris
was washed with a high turbulence wash.
Each batch of debris was cleaned for one
hour in the spray tank and one hour in the
wash tank. During both the spray and wash
cycles, a portion of the cleaning solution was
cycled through a closed looped system where
the oil/water separator removed the oil/PCB
contaminants. The remaining cleaned
solution was then recycled. After the wash
cycle, the debris basket was retimed to the
spray tank, where it was rinsed with water.
After completion of the cleaning
process, post treatment wipe samples were
obtained from each of the transformer pieces
to compare with the before treatment
samples. Concentrations before treatment
ranged from 0.1 to 98 ug/100 cm2. After
treatment all but seven of the 75 transform-
ers showed concentrations less than the
minimum allowable level of 10 ug/100 cm .
The seven transformers that did not meet
Jet Fuel
(from page 1)
The nitrate and nutrients were batch
mixed in separate polyethylene tanks and
fed into the infiltration gallery and a
groundwater recirculation system through
automatically controlled chemical feed
pumps. The pump flow rates were
adjusted weekly to compensate for
changes in nitrate and nutrient composi-
tion in the recirculated water. The
recirculated water was sampled weekly
from cluster wells that had pipe lines
routed below land surface to the building
that also housed the nitrate feed tanks.
The sampling revealed that, after the
addition of nitrates, toluene levels
dropped rapidly in the fuel spill, but took
a much longer time in the recirculated
water. Ethylbenzene and m+p-xylene
were also removed after the addition of
the nitrates; however, o-xylene was not
found to biodegrade until toward the end
of the demonstration. Overall, toluene
levels dropped from 4500 to less than
1 (jg/L, ethylbenzene levels from 840 to
6 ug/L and o+p+m -xylene levels from
4,000 to 60 ug/L.
For more information, call John
Wilson of EEA's Robert S. Kerr Environ-
mental Research Laboratory at FTS-743-
or 405-332-8800.
acceptable levels were rewashed, after which
all seven had PCB concentrations below the
detection limit of 0.1 ug/100 cm2. All of the
transformers could be sold to a scrap metal
dealer or to a smelter for muse.
The surfactant solution and rinse water
were neutralized to a pH of 8, using concen-
trated sulfuric acid, and then passed through
a series of particulate filters on an activated
carbon drum. Finally, they were passed
through an ion exchange column. After the
treatment, the PCB concentration was reduced 1
to below the detection limit of 0.1 ug/L.
The DWS was also demonstrated at
Shaver's Farm with drums containing the
herbicide Dicamba and benzonitrile, a pre-
cursor in the manufacture of Dicamba. Be
fore treatment, some concentrations of ben- -
zonitrile ranged as high as
(see Debris Washing, page 4)
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Air Emissions from Soil Excavation
Controlled by Tent Enclosure with
Exhaust System
by Jack Hubbard, Superfund Innovative Technology Evaluation Program
VOCs, SO,
Enclosure with
exhaust
system
the McCall Superfund Site in Fullerton,
CA has aviation fuel refinery wastes-
mud, tar and char—from oil refinery and
drilling operations. Pre-remedial investi-
gations concluded that excavation of the
waste potentially could release significant
air emissions of volatile organic com-
pounds(VOCs) and sulfur dioxide (S02)
to the surrounding community. To safe-
guard against such a problem, a trial exca-
vation was conducted within a temporary
tent enclosure with air from the enclosure
vented through an exhaust treatment sys-
tem. The exhaust system consisted of a
sodium hydroxide-based wet scrubber and
an activated carbon bed adsorber, the pur-
pose of which was to reduce emissions of
sulfur dioxide and organic compounds.
The air emission objectives of the demon-
stration were to measure the extent of
emissions that might occur during excava-
tion, to assess emission control provided by
the enclosure and its exhaust treatment sys-
tem and to monitor emissions at the site
bonndaly. The demonstration was conducted
as part of the Superfund Innovative Technol-
ogy Evaluation (SITE) Program at EPA's
Risk Reduction Engineering Laboratory.
During the excavation, unexpected high
levels of S02 and total hydrocarbons (THC)
were encountered. For example, during tar
excavation five-minute average values for
SO, reached 1,000 parts per million (ppm)
and THC levels reached 492 ppm. How-
ever, the enclosure's exhaust treatment sys-
tem removed up to 99.9% of the SO, and up
to 90.7% of the THC. The demonstration
indicated that excavation is feasible under an
enclosure and that the emissions from the
enclosed site could be effectively treated
with no adverse impacts noted at the site
boundary. Excavation and waste handling
activities would not be feasible without an
enclosure and an air treatment system.
This SITE demonstration also sought
to: (1) better determine the nature of the
waste and the treatment needed to improve
its handling characteristics; (2) study the ef-
fect of vapor-suppressing foam during exca-
vation activities; and (3) determine prob-
lems that might occur during excavation for
full-scale remediation. The results indi-
cated that the waste could be easily treated
for further processing in a thermal destruc-
tion unit. Because the waste failed the
Toxicity Characteristic Leaching Procedure,
it would not be possible to simply excavate
it for redisposal without treatment. Vapor
suppressing foams did not perform as an-
ticipated.
For more information, call Jack
Hubbard of EPA's SITE Program at FTS-
684-7507 or 513-569-7507.
Chemical Reagent at Lee Farm Reduces both
Lead Levels and Soil/Ash Volume
by Steven Faryan, On-Scene Coordinator, Region V
Lead
Chemical
fixation
Soil
new process used at the Lee Farm
Site, an abandoned battery dump in
Woodville, WI, not only reduced
leachable lead levels in soil from 200-
300 to 1-2 mg/L but also decreased soil
volume by 22% The leachable lead
level in the black ash from satellite sites
was similarly reduced from 348 to
1 mg/L and the black ash volume was
decreased by 50%. Lead levels after
treatment comply with the new land
disposal restrictions for lead and are
below the regulatory standard for the
Toxic Characteristic Leaching Proce-
dure (TCLP). The treatment, a trade-
marked chemical fixation process, adds
chemicals (reagents) to the contami-
nated soil that change the form of the
contaminant so that it is no longer soluble
in water. The process is known as the
MAECTITE process and was developed
by MAECORP of Chicago, IL.
The treatment has several steps.
First, the brown soil material is screened
so that oversized pieces larger than three
to five inches in diameter are removed
from the rest of the material which is
mixed with a trademarked powder as it
proceeds on a conveyor through a
shredder/grinder. The material is then
conveyed into a pug-mill mixer where a
trademarked liquid solution with the
reagents is added. This mixture is
agitated and then conveyed onto a clay
pad where it has a curing time of six to 24
hours. Curing time is the time it takes for
the chemicals to react with the contami-
nated materials to reduce the leachable
lead levels. After results from an off-site
laboratory confirm that TCLP results of
less than 5 mg/L is met, the friable
material is placed at one end of the site
where eventually a clay cap will be
compacted over the area.
The treatment of the black ash is
slightly different in that a second trade-
marked pozzalime powder is added as
well. This additional powder is necessary
because of the extremely high levels of
lead (up to 22%) and the low pH of the
(see Lead, page 4)
-------
Conference
Alert
The Third Forum on Innova-
tive Hazardous Waste
Treat merit Technologies:
Domestic and International,
sponsored by EPA, will be
held at the Fairmont Hotel,
Dallas, Texas on June 11-
13,1991. International and
domestic vendors of inno-
vative hazardous waste
treatment technologies will
present over 25 technical
papers and 60 displays.
Case studies of applied
technologies In real-life
situations will be presented.
For registration Informa-
tion, contact; MCA Corp,,
550 Plnetown Road, Fort
Washington, PA 19034
Telephone: 215-643-5466*
Lead
(from page 3)
untreated soil. This Spring a rotary drum
screen will be used to treat the oversized
material.
The oversized material is batch-
treated in a seven-cubic yard capacity
rotary mixer where the reagents are added
directly to the mixer and agitated. TCLP
levels after treatment are below 5 mg/L.
About five batches are treated a day.
Before the on-site activities began at
Lee Farm, EPA's Technical Assistance
Team collected soil samples and
MAECORP performed a series of treat-
ability studies and bench scale test runs.
Prior mineralogy studies indicate that the
lead is transformed into apatite and
anglesite minerals which are extremely
immobile and stable. Actual treatment at
Lee Farm has successfully chemically
fixed over 12,000 tons of lead contami-
nated soils, battery casings and debris,
averaging 275 tons per day. EPA plans to
demonstrate the process at another site as
part of its SITE program.
For more information, call Steve
Faryan, the Region 5 On-Scene Coordina-
tor for the Lee Farm Site, at FTS-353-935U
or 312-353-9351.
Debris Washing
(from page 2)
47,000 ng/100 cm (averaging
4,556 ug/100 cm . Post treatment samples
averaged 10 jig/100 cm , with a range from
below the detection limit to 117 jjg/100 cm .
Before treatment, some Dicamba values
?
ranged as high as 180 jig/100 cm (averag-
ing 23 ng/100 cm ). Post treatment concen-
trations tanged from below detection limits
to 5.2 ng/100 cm and averaged
1 ng/100 cm . The water treatment system
was effective in reducing contaminant con-
centrations, with the exception of arsenic
and Dicamba, to below the detection limit.
The system has been successfully used
to remove PCBs and certain pesticides, di-
oxins and furan residues. While the system
has not been tested for removal of all types
of organic contaminants from surfaces of
debris, results are promising. A full scale
system is being developed for further dem-
onstration. IT Environmental Programs,
Inc. (formerly PEI Associates, Inc.) will
commercialize the technology.
For more information, call Naomi
Barkley at EPA's Risk Reduction
Engineering Laboratory at FTS-684-7854
or 513-569-7854.
Tech Trends welcomes readers' comments, suggestions for future articles and contributions.
Address correspondence to: Managing Editor, Tech Trends (OS-110W),
U.S. Environmental Protection Agency, 401 M Street, S.W., Washington, DC 20460.
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Environmental Protection
Agency
Center for Environmental Research
Information
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