Abstract
Groundwater contamination due to chlorinated hydrocarbons like trichloroethylene and tetrachloroethylene has been a great environmental issue in Japan. Because these substances are volatile and little soluble in water, and can exist in unsaturated zone as vaporized, dissolved and undiluted non-aqueous phases, they migrate as gas-water-liquid three phase flow in subsurface. Recently, the air sparging coupled with the soil vapor extraction as the physical remediation technologies has been applied to a site contaminated with chlorinated hydrocarbons. The air sparging technology facilitates the contaminant volatilization with air injected into saturated zone and the soil vapor extraction technology extracts the contaminant in soil and injected gas. Therefore, in order to establish these technologies, it is indispensable to understand the mechanism of gas-water two phase flow in subsurface.
