Abstract
The removal of volatile organic compounds (VOCs) underlying the vadose zone in a pool of nonaqueous phase liquid (NAPL) in the vicinity of a soil vapor stripping well is modeled mathematically. The diffusivity of the VOC is an important parameter determining the rate of removal of the NAPL; diffusivities of hexane, toluene, trichloroethylene, tetrachloroethylene, and 1,1,1-trichloroethane were determined in fine sand and found to be approximately 2 × 10−6 m−2/s at 25°C. Vapor stripping appears to be a practical method for the removal of NAPL floating on the water table or confined there by capillary pressure, as indicated by mathematical modeling and by bench-scale soil vapor stripping experiments.