Effect of water content and soil type on mass transfer limitations to the soil vapour extraction process
Laboratory studies were completed to investigate the functionality between water content and soil type on mass transfer processes during soil vapour extraction (SVE). An automated, bench-scale SVE system was developed. The contaminant used was a mixture of toluene and m-xylene. A functionality with water content was apparent in the Delhi loamy sand. This functionality was less evident in the Elora sift loam and negligible for the Windsor clay loam. The mass transfer limitation increases in the air-dry columns from the sand to the clay. This functionality was minimal at the middle moisture content and negligible at the wettest conditions tested. Finally, fitting an existing SVE model to the experimental results was attempted. The ability of the model to characterize system performance was limited by the kgamax/kgamin expression used to describe the mass transfer between the air and immiscible phases.