Dissolution of a well-defined trichloroethylene pool in saturated porous media: Experimental design and aquifer characterization

Abstract

A unique three-dimensional bench-scale model aquifer is designed and constructed to carry out dense nonaqueous phase liquid (DNAPL) pool dissolution experiments. The model aquifer consists of a rectangular glass tank with internal dimensions 150.0 cm length, 21.6 cm width, and 40.0 cm height. The formation of a well-defined circular pool with a perfectly fiat pool-water interface is obtained by a bottom plate with a precise cutout to contain the DNAPL. The aquifer is packed with a well-characterized relatively uniform sand. A conservative tracer is employed for the determination of the longitudinal and transverse aquifer dispersivities. The dissolution studies are conducted using a circular trichloroethylene (TCE) pool. The sorption characteristics of TCE onto the aquifer sand are independently determined from a flow-through column experiment. Steady state dissolved TCE concentrations at specific downstream locations within the aquifer are collected under three different interstitial velocities. An appropriate overall mass transfer coefficient is determined from each data set. The data collected in this study are useful for the validation of numerical and analytical DNAPL pool dissolution models.