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Confidential Client
Northeast, USA
Project
In Situ Treatment of Bis (2-ethylhexyl)
phthalate (BEHP) Impacted Soil
Summary
DARAMEND® technology was selected as the
remedial option of choice for the in
situ treatment of 14,000 tons of BEHP
impacted soil at a former plastics manufacturing
facility in New Jersey. Surface soil (0-2 ft) was
cleared of oversized debris and boulders (>6")
using a bulldozer equipped with sub-soilers
(equipment attached to a tractor to unearth large
debris within the soil) and loaders equipped with
a specially designed stone fork implement.
The Challenge
The remedial goal of 210 mg/kg for BEHP had to be
achieved in the upper two feet of all impacted
areas of the site. Some regions of the site also
required treatment of PAHs to NJ Department of
Environmental Protection (DEP) industrial direct
contact criteria. Over 4 acres of the 12-acre
site required treatment. In some of the treatment
areas activities had to be coordinated with tidal
fluctuations, since the water table (which was
very close to the surface in these locations) was
substantially influenced by the tide.
The Solution
Following preparation of the treatment area,
DARAMEND® was applied in situ using
a site-specific aerobic protocol. In
situ application of the technology
eliminated the costs for soil excavation and
construction of a treatment cell. The process
required the addition of nutrients and
proprietary organic amendments to optimize the
rate of microbial activity in the soil. The
process also required control of the soil
moisture content through irrigation and tillage.
Tilling was accomplished using a specialized
rotary tiller with the capacity to till to a
depth of 2 ft.
The Result
The mean concentration of BEHP was reduced from
1,250 mg/kg to less than 150 mg/kg after
approximately 10 months of active treatment. The
remedial goal of 210 mg/kg was achieved in all
regions of the site. Elevated PAH concentrations
were also reduced to below the NJ DEP criteria
within the same timeframe.
The Cost
Cost to treat approximately 14,000 tons of soil
at this site averaged approximately $35/ton.
Treatment costs were particularly low at this
site because soil was treated in situ.
The Timeline
Treatment goals were attained after approximately
14 months, between May 1999 and June 2000,
including 10 months of active treatment and 4
inactive months during the winter.
Figure 1. Influence of DARAMEND®
bioremediation on phthalate impacted
soil.
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