PROJECT B-2
Ex Situ Treatment Projects (in Lifts or Bio-Piles)
Former Fueling Facility, Taunton, MA
PROBLEM:
Long-term low level petroleum-based releases at a former bulk plant
A release of gasoline and kerosene to the environment was discovered
in June of 1997 during closure of a former large bulk plant terminal
in eastern Massachusetts. The release was discovered during the
decommissioning and removal of aboveground tanks, underground tanks,
and associated pumps, piping, and dikes. Soils were analyzed for
volatile petroleum hydrocarbons (VPH) and the results exceeded the
Massachusetts Contingency Plan (MCP) cleanup standards applicable to
the site.
SOLUTION:
Ex situ bioremediation of 300 yards of contaminated soil in a bio-treatment bed on site
During September 1997, approximately 300 cubic yards of
gasoline/kerosene contaminated soils were excavated and spread within
a single bio-treatment bed measuring approximately 40 feet by 90
feet. The bio-treatment bed bottom and sidewalls were lined with 6 ml
polyethylene, and the sidewalls were bermed to contain runoff from
precipitation and spray irrigation. The contaminated soil was spread
to an average depth of 2 feet over the entire biotreatment bed. Hay
was continually mixed in with the soil during placement. Prior to
bioremediation, numerous soil samples were obtained and analyzed for
VPH. During early October 1997, the biological treatment was initiated
by mixing 75 pounds of MicroSorb® Super Concentrate
Microbes, 20 pounds of MicroSorb® Nutrients, and 2000
gallons of MicroSorb® Biocatalyst in one tank truck.
The bioremediation mixture was then sprayed over the entire
bio-treatment bed. An automated irrigation system was installed to
regularly apply de-chlorinated water over the bio-treatment
bed. During December 1997 the bio-treatment bed was covered with a
black poly liner to promote biodegradation during the winter
season.
RESULTS:
Contaminated soils bioremediated to the most stringent standards - cost approximately $15/cubic yard
In June, 1998, oil samples were obtained to evaluate the effectiveness
of the augmented bioremediation. Results of the VPH analysis
indicated that over 80% of the bio-treatment bed had VPH levels below
the applicable S-1/GW-3 cleanup standard. On average, the C5-C8
aliphatics had been reduced from over 800 ug/g to less than 100 ug/g;
the C9-C12 aliphatics were reduced from 1,800 ug/g to less than 120
ug/g; and the C9-C10 aromatics were reduced from 600 ug/g to less than
50 ug/g. During October 1998, 12 months after the initial
bioremediation application, final soil samples were obtained and all
VPH concentrations were below the applicable S-1/GW-3 cleanup
standard. The ex situ bioremediation was considered complete at this
time. The contaminated soils were bioremediated to the most stringent
Massachusetts cleanup standard for a cost of approximately $15.00 per
cubic yard.
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