Validity of the Use of the Mass Transfer Parameters Obtained with 1D Column in 3D Systems during Soil Vapor Extraction

Abstract

The efficiency of soil vapor extraction (SVE) depends primarily on mass transfer parameters. The objective of this work was to determine whether mass transfer parameters obtained from calibrating a model against unidirectional column experiments could be used for three-dimensional (3D) applications. A 3D experimental setup was designed and constructed to simulate a decontamination system at the bench scale. A mathematical model simulating multiphase flow and multicomponent transport of contaminants in the subsurface under nonequilibrium transient mass transfer conditions was developed and used. Results showed that the mass transfer parameters obtained from unidirectional column assays were several orders of magnitude greater than those obtained with the 3D trials. Quantitative analyses of the experimental data showed that mass transfer limitations occurred in 3D. Mass transfer coefficients are related to the distribution of air velocity in the 3D reactor. Consequently, unlike the 1D column, mass transfer coefficients may not be linked to a single value of air velocity.