Description
Confidential Client Ontario, Canada Project
Pilot-Scale demonstration on soil
containing phenoxy-acid herbicides (2,4-D, and 2,4,5-T) , and other
chlorinated pesticides (DDT, DDD, and DDE)
Summary
The application of DARAMEND® served to reductively de-chlorinate, and
subsequently mineralize the chlorinated herbicides and pesticides.
The Challenge
Treatment of 350 tons of soil impacted by phenoxy-acid herbicides
(2,4-D, and 2,4,5-T), and other chlorinated pesticides (DDT, DDD, and
DDE).
The Solution
The treatment process involved the application of DARAMEND to a 60 cm
thick layer of soil within a treatment cell. Due to the volatile and
highly toxic nature of the phenoxy-acid herbicides the treatment cell was
covered with a polyethylene clad greenhouse. Negative pressure was
maintained within the greenhouse by continuously drawing air from the
greenhouse and discharging it through a granular activated carbon filter.
Soil undergoing treatment was subjected to several treatment cycles and
was irrigated to 90% of the soil water holding content at the start of
each treatment cycle.
The Result
The concentrations of the target contaminants, 2,4-D, 2,4,5-T, and DDT,
were reduced by over 96%, 84%, and 91% respectively (Figure 1). Initial
mean concentrations of 97.7 mg/kg, 8.1 mg/kg, and 54 mg/kg, were reduced
to 3.6 mg/kg, 1.3mg/kg, and 4.7mg/kg, respectively.
The Cost
The estimated treatment cost for the full-scale application of
DARAMEND® bioremediation at this site, which would have involved the
treatment of 35,000 tons of similarly contaminated material, was
approximately US$127.00/ton. The cost associated with this project is
slightly elevated when compared with most similarly sized projects due to
the extremely toxic and semi-volatile nature of the contaminants, and
consequently, the extraordinary steps required to ensure workplace safety
and to prevent any environmental impacts during treatment.
The Timeline
Treatment of this material to the above levels required the application
of nine treatment cycles. At this site, each treatment cycled required
approximately one month, for a total active treatment period of
approximately 9 months. Although one month was required per cycle during
this pilot-application, improvements made in the application procedures
for this technology have reduced the time required per cycle to an average
of about 10 days.
Using improved techniques Adventus estimates that the same level of
treatment could now be accomplished in 3 to 4 months.
Companies On This Project
ADVENTUS GROUP
