Superfund Innovative Technology Evaluation (SITE)
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Technology GRACE Bioremediation Technologies Innovative Technology Evaluation
Grace Dearborn's DARAMEND Bioremediation Technology was developed to treat soils/sediment contaminated with organic contaminants using solid-phase organic amendments. The amendments increase the soil's ability to supply biologically available water/nutrients to microorganisms and bind pollutants to reduce the acute toxicity of the soil's aqueous phase. Prior to technology application, soils are screened approximately to 10 cm in diameter to remove any debris. The technology can be applied either in-situ or ex-situ. Application involves the mixing of soils with amendments to a depth of 0.6m. Amended soils are then irrigated/tilled to encourage microbial growth and metabolic activity until target compounds are reduced below regulatory action levels. A soil cover may be used to control soil moisture and run-on/off. The soil cover also has the effect of maintaining elevated soil temperatures negating the usual problems experienced when applying bioremediation systems in cold climates. This technology was demonstrated at the Domtar Wood Preserving Facility, Trenton, Ontario, Canada, during an eleven-month period from October 1993 to September 1994 using soil contaminated with polyaromatic hydrocarbons (PAH) and chlorinated phenols. The developers claimed 95% reduction in total PAHs and total chlorophenols. Demonstration soil sampling revealed that PAH's were reduced from 1,710 mg/kg to 98 mg/kg (94.3%), total chlorophenols were reduced from 352 mg/kg to 43 mg/kg (87.8%), and total recoverable petroleum hydrocarbons were reduced from 7,300 mg/kg to 932 mg/kg (87.3%). The technology also reduced soil toxicity to earthworms and plant seeds.