Title: PHOTOTREATMENT OF PERCHLOR- OETHENE IN SOIL VAPOR AT THE HARRISON LANDFILL, TUCSON, AZ
Abstract: Perchloroethene (PCE) was scrubbed from contaminated landfill soil vapor by contact with a mixture of 2-propanol and acetone and then destroyed by a reductive dehalogenation process during exposure to sunlight in a photoreactor. The treatment system (scrubber and photoreactor) was deployed at the 120-acre Harrison Landfill, which was closed and capped in 1997. Soil vapor containing 100-200 µg L -1 PCE (and other chlorinated organics) was readily obtained by diverting a flow of soil vapor from the city’s full-scale carbon adsorption treatment system to our experimental phototreatment system. Two types of field experiments have been conducted to date. In the first quasi-batch mode, the solvent was pre-loaded with PCE throughout the night and then exposed to sunlight while being recirculated in the photoreactor during the day. In the second continuous mode, both the scrubber and photoreactor were operated simultaneously for extended periods. The effectiveness of the photoreactor was determined by comparing liquid-phase concentrations of PCE and other targets in the reactor influent and effluent. PCE concentrations were lowered by 90 percent in a matter of hours. Results also indicate that the reaction was inhibited by oxygen in the soil vapor (currently 15 percent due to the injection of air by city contractors). However, we were able to eliminate (photoreduce) interfering oxygen and the target PCE by increasing the number of photoreactor tubes.
Publication Year: 2000
Publication Date: 2000-01-01
Language: en
Type: article
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