Flow and transport modeling of a heterogeneous field site contaminated with dense chlorinated solvent waste

Abstract

Fluid flow and contaminant transport at a heterogeneous field site with an extensive vadose zone are modeled to study the impact of the presence of dense non-aqueous phase liquids upon ground water remediation. Results of aqueous phase mass balances using measured data indicate the existence of a continuing source of trichloroethylene to ground water during remediation. Overall mass balances indicate that ground water extraction has removed a small fraction of total subsurface trichloroethylene in 5 years. The rate of mass transfer of trichloroethylene entering the aquifer as a function of time and location is calculated using system performance data and results of a simulated remediation in which all sources to the ground water are removed. The resulting expressions are evaluated by comparing to results of mass transfer models. The results indicate that the existing ground water extraction system alone must operate for thousands of years to achieve remediation goals.