Laboratory-scale analysis of aquifer remediation by in-well vapor stripping 2. Modeling results

The removal of volatile organic compounds (VOCs) from groundwater through in-well vapor stripping has been demonstrated by Gonen and Gvirtzman (1997, J. Contam. Hydrol., 00: 000-000) at the laboratory scale. The present study compares experimental breakthrough curves with those predicted by three-dimensional numerical simulation of VOC transport, volatilization, and removal. We are able to sufficiently model the behavior of the laboratory system by assuming an isotropic, homogeneous hydraulic conductivity field and uniform linear retardation of the VOCs. The exponential reductions in concentrations of trichlorethylene, chloroform, and toluene were well represented by the simulation model. Local disparities between experimental and simulated breakthrough curves appear to result primarily from differences between the actual and estimated initial concentrations, and secondarily from differences in the actual and modeled flow field. Our analysis suggests that the in-well vapor stripping process is understood at the laboratory scale. The model developed for this work provides a sound basis for current analysis at the field scale.