ABSTRACT: Groundwater at an active manufacturing facility in Portland, Oregon was impacted by trichloroethene (TCE) and its degradation products (primarily cis-1,2- dichloroethene (DCE) and vinyl chloride [VC]) up to maximum concentrations of 592,000; 90,000 and 5,000 micrograms per liter (ug/L), respectively. Natural attenuation was identified as a significant on-going process but was insufficient to be protective of downgradient receptors. Groundwater discharges to a river approximately 450 ft downgradient of a suspected source area. A number of bioremediation technologies were evaluated at the bench-scale level to complete the degradation of TCE and its byproducts. The bench test compared the performance of the bioremediation technologies at TCE concentrations ranging from 10,000 to 870,000 ug/L. At the conclusion of the bench tests, EHC™ was shown to most effectively stimulate the degradation of TCE and its degradation products, especially at the higher concentrations. The addition of KB-1™ inoculum served to increase some reaction rates thus supporting complete dechlorination. Accordingly, an integrated field pilot test of EHC and KB-1 was conducted in two areas (source area and riverbank area). The objectives of the field tests were to: i) validate remedial performance under field conditions, and ii) assess the effectiveness of the construction methodology (i.e., direct injection of EHC slurry at depths of 80 to 130 ft below ground surface [bgs]).
Integrated Use of EHC™ and KB-1 for Source Area Treatment and PRB Applications at a TCE Impacted Site.
Battelle’s 9th International In Situ & on-site Bioremediation Symposium, Baltimore, MD May 7–10, 2007