Soil Clean Up byin-situAeration. XV. Effects of Variable Air Flow Rates in Diffusion-Limited Operation

Abstract

Abstract A model for soil vapor extraction (SVE) is developed which includes the effects of mass transport kinetics of VOC between nonaqueous phase liquid (NAPL) droplets and the aqueous phase, and between the aqueous and vapor phases. The model permits time-dependent gas flow rates in the vapor extraction well. The model is employed to demonstrate the effectiveness of certain types of pilot-scale SVE experiments in determining the rate of mass transport processes. It is also used to explore several time-dependent air flow schedules for SVE well operation. The results indicate that the use of suitably selected air flow schedules in SVE can result in greatly reduced volumes of air to be treated for VOC removal with relatively little increase in the time required to meet remediation standards.