Experimental Investigation of the Interaction of Soil Air Permeability and Soil Vapor Extraction

Abstract

Soil vapor extraction column experiments were performed to investigate contaminant removal and its interaction with soil air permeability. Water, TCE, and PCE, and a mixture of TCE and PCE were used as contaminants. Three gradations of Ottawa sand were used at relative densities of 0.60 and 1.0: medium, fine, and uniform. Soil air permeability was found to increase linearly with time by 25–150 % to a maximum value when the contaminant was completely removed. The largest increase in soil air permeability was found for fine and/or dense samples. The experimental data were used in a previously developed model by Farhan in 1998 and Farhan et al. in 2001 to predict column behavior. In general, the model predictions were in good agreement with the experimental results. They revealed that the assumption of local equilibrium between the pore air and contaminants is valid for a wide range of pore velocities (2.0–9.2 cm/s).