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Confidential Client
Northwest, USA
Summary
Adventus’ DARAMEND® technology was
selected to remediate approximately 6,000 tons of
soil impacted with pentachlorophenol (PCP) at a
former chemical manufacturing facility located in
the Northwest. Excavated soil was placed in a
lined bioremediation cell in a 2 ft layer for
treatment.
The Challenge
To reach a remedial goal of less than 50mg/kg in
each soil sampling zone, containing approximately
175 tons each. The concentration of PCP in some
sampling zones was as high as 2,000 mg/kg
initially. This concentration would be considered
by many as acutely toxic to most microbial
populations, rendering the soil non-amenable to
standard bioremediation practices.
The Solution
Following homogenization of the soil undergoing
treatment, DARAMEND® was applied using a
site-specific aerobic protocol that utilized
indigenous micro organisms. The technology
involved the addition of proprietary organic
amendments and site-specific nutrient supplements
designed to optimize the rate of microbial
activity in the soil. The soil moisture content
was then maintained at a relatively constant
level (approximately 60% of the soil water
holding capacity). The soil was tilled
periodically to maintain an aerobic soil
environment. Tilling was accomplished using a
tractor mounted specialized deep rotary tiller
with the capacity to till a depth of 2 ft.
The Result
PCP concentrations were reduced from as high as
2,000 mg/kg in some sampling zones to less than
30 mg/kg. The mean PCP concentration was reduced
from 359 mg/kg to 16 mg/kg after approximately 8
months of treatment in 1999. The remedial goal of
less than 50 mg/kg was met and surpassed in all
sampling zones.
The Cost
The cost to apply DARAMEND® at this site was
only $37/ton; however, a significant portion of
the site work was conducted by the site
owner.
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