INFLUENCE OF WATER EVAPORATION ON SOIL VAPOR EXTRACTION (SVE)

As SVE proceeds large amounts of water are withdrawn from the soil wit h the gaseous stream together with the contaminants. This may lead to important variations in the pneumatic soil permeability and changes in the soil temperature. A one-dimensional column mathematical model is developed to study these effects, based on the Millington and Quirk ex pression and assuming local thermal equilibrium and fast water mass tr ansfer from the condensed to the gaseous phase. This model yields a go od agreement with experimental results obtained with fine-sand lab col umns. The molar flux increases during the process, but most of this in crease takes place during the latter period of the drying process. Imp ortant temperature drops (up to 10 degrees-C) are also expected when r elative moisture of the air is low.