Experimentation and Modeling Study of Multiphase Extraction at the Laboratory Pilot Scale

This work investigated the treatment of a heterogeneous soil by multiphase extraction (MPE), which is a physical remediation method for soils containing volatile organic compounds. Experiments were conducted on a two-dimensional (2D) laboratory pilot. The soil was simulated by sand in which one or two clay barriers were introduced. The pollutant used was n-decane (concentration 50 g/L) in hexane, acting as the solvant. The mixture of n-decane in hexane was introduced in the soil, and the infiltration of the contaminant and its extraction were modeled and experimentally verified. The extraction time and the extraction yield were determined experimentally by monitoring the pollutant concentrations over time during treatment. The influence of barriers on the treatment time and on the adsorption in solid phase in both the vadose and the capillary zones was highlighted. The installation of a clay barrier increased the treatment time but produced an almost identical yield to that obtained with sand alone.