Estimate the contaminant removal rate (in the absence of the free-product phase) A subsurface is contaminated with benzene. The average benzene concen- tration of the soil samples, taken from the contaminated zone, was 500 mg/kg. The following data were obtained from the remedial investigation and a pilot test: Pressure at the extraction well = 0.9 atm Pressure at a monitoring well 30 ft away from the venting well =0.95 atm Diameter of the venting well = 4 in Permeability of the formation = 1 Darcy Well screen length = 20 ft Viscosity of air = 0.018 centipoise Porosity = 0.35 Organic content = 0.03 Water saturation = 45% Subsurface temperature = 25C Bulk density of soil = 1.7 g/cm3 Estimate the contaminant removal rate at the beginning of the project