Remediation of Dissolved-Phase Chlorinated Hydrocarbons in Fractured Bedrock Using Emulsified Vegetable Oil

摘要

At a former chlorinated hydrocarbon chemical transfer facility in Buffalo, New York, an approximately one-year pilot study was implemented under the New York State (NYS) Superfund program to evaluate the impact of emulsified vegetable oil, in particular Emulsified Oil Substrate (EOS)~R, on concentrations of chlorinated hydrocarbons in the offsite dissolved phase groundwater plume within a fractured bedrock aquifer and, if successful, to develop a basis for full-scale design. EOS acts as a hydrogen donor in anaerobic biological reactions that lead to reductive dechlorination. Tetrachloro-ethene (PCE) and trichloroethene (TCE) are the primary contaminants; secondary contaminants include the degradation products cis-l,2-dichloroethene (cDCE), trans-1,2-dichloroethene (tDCE), and vinyl chloride (VC). Both primary and secondary contaminants were present significantly above the NYS groundwater standards. EOS was applied using 24 bedrock injection wells. A packer assembly and pump was used successfully to inject EOS in bedrock. Based upon the groundwater monitoring analytical data, EOS injection in the pilot test area has induced anaerobic biological activity, which has promoted very strong reductive dechlorination. Concentrations of the primary chlorinated compounds have been reduced to below NYS groundwater criteria. Based upon these successful results, NYS is now implementing full-scale design of EOS in the source area.