Induced cometabolism of chlorinated VOCs using propane

摘要

propane is bing injected into an aquifer contaminated with chlorinated volatile organic compounds (VOCs) to induce cometabolic degradation of the chlorinated compounds. Cometabolism of the chlorinated VOCs was observed within the aquifer when fuel hydrocarbons migrated into the aquifer from an upgradient bulk fuel terminal. The cometabolic degradation of the VOCs appears to have ceased concurrent to the disappearance of the fuel hydrocarbons. Propane was selected to replace the fuel hydrocarbons as a source of anthropogenic carbon in an effort to stimulate the cometabolic process. A field-scale pilot test was implemented at the laundry facility utilizing propane as an alternative carbon source. Propane was injected in pure form at a rate of 4 cubic feet per minute (CFM) for two minutes every six hours. The propane injection is followed by three hours of air injection for an air to propane injection ratio of approximately 100:1. Preliminary and follow-up groundwater sampling results showed propane to be dissolving into the groundwater and a devrease in dissolved chlorinated VOC concentrations was observed in wells surrounding the propane injection well. A temporary disruption in propane injection showed a rapid disappearance of the dissolved propane and a minor rebound in dissolved chlorinated VOC concentrations.