Transition from Active to Enhanced Attenuation (EA) Using Passive Soil Vapor Extraction (PSVE)(Abstract)

摘要

The use of Passive soil vapor extraction (PSVE) in transition to EA of volatile organic compounds (VOCs) along an abandoned sewer line at the Department of Energy’s Savannah River Site in Aiken, SC has been field tested and modeled. The area studied is the former location of a 2000 ft long vitrified clay tile pipe, through which multiple VOCs were emitted, primarily trichloroethylene (TCE) and polychloroethylene (PCE). Cracks occurred along the slip joints connecting the sections of pipe which led to multiple point sources of VOCs in the unsaturated zone. This zone is approximately 130 feet thick. Active soil vapor extraction (ASVE) was performed on most of the area, removing a significant amount of the contaminants. However, there was sufficient resid- ual contamination resulting in a low concentration but long-lived source of VOCs to the groundwater. In order to keep this residual from reaching the water table, additional treatment was needed. The challenge was to identify a treatment that would result in a continuing decrease in VOC loading to the saturated zone and would have a low energy requirement. PSVE (barometric pumping) was selected for this site.