Modeling of TCE Contamination and Recovery in a Shallow Sand Aquifer

Authors: K. Freeberg, P. Bedient, J. Connor
Published: January 1987 in Ground Water volume 25 (1) pages 70-80.

Abstract

The U.S. Geological Survey (USGS) Solute Transport Model is a widely used, well-documented computer code which simulates contaminant transport in ground water using a finite-difference grid and the method of characteristics. In this study, the model was applied to an industrial site where trichloroethylene (TCE) and other industrial solvents had contaminated a shallow sand aquifer. At the study site, the geology was well-characterized and the migration of the contaminant plume was monitored by a network of 15 wells.

Although the rate of release of the industrial solvents to the aquifer was unknown, the model gave a good prediction of the movement of the plume when the release of contaminants was modeled as a point source injection. The model was also successful in simulating the behavior of the plume under the influence of a recovery system. During simulation of a four-well withdrawal system, model predictions of TCE concentrations and hydraulic head in the aquifer matched actual data collected at two points in time after start-up of the recovery system. The model predicted that the same configuration of withdrawal wells would reduce concentrations of TCE in the ground water from approximately 1000 μg/1 to 6 μg/1 after two years of pumping.