Transport of dissolved contaminants originating from a rectangular prism-shaped, multicomponent nonaqueous-phase liquid source in saturated porous media

Abstract

In this study, a three-dimensional semi-analytical model for simulating the transport of contaminants originating from a dissolving, rectangular prism-shaped, multicomponent nonaqueous-phase liquid (NAPL) source in homogeneous, saturated porous media is presented. The NAPL dissolution process for each component is envisioned to occur in a series of consecutive short intervals (pulses). The equilibrium aqueous concentration and the source dimensions are assumed to remain constant for the duration of each pulse. Individual component aqueous phase concentrations resulting from each dissolution interval are determined by an existing, single-component analytical solution. A synthetic NAPL mixture consisting of tetrachloroethylene and trichloroethylene was used for model simulation. Results show that for a dissolving multicomponent NAPL mixture, downstream aqueous-phase concentrations may not always reflect source characteristics. The model is useful for an understanding of field data in homogeneous subsurface formations and for interpretation of bench-scale laboratory experiments.