Superfund Research Program
Sequestration Processes for Attenuation and Treatment of Arsenic and other Toxic Elements in Mine Waters
Final Progress Reports
Conducting accurate risk assessments and implementing efficient, cost-effective remediation efforts for hazardous-waste sites requires an understanding of contaminant distribution, transport, and fate in the subsurface. Studies are being conducted to examine the distribution, mass-transfer, and remediation of chlorinated solvents in heterogeneous porous media. This research is designed to examine mechanistic behavior ranging from the pore scale to the field scale. One of the several components involves investigation of remediation methods for chlorinated solvents. In the past few years, great interest has been generated regarding in situ chemical oxidation (ISCO) as a potential method for remediation of chlorinated-solvent source zones. In this method, a solution containing an oxidative compound such as permanganate is injected into the subsurface, with the objective to have the oxidant react with and destroy the contaminant. Successful application of ISCO requires an understanding of possible limitations to effectiveness. One major issue concerns preferential flow of the reagent in heterogeneous systems and poor access to the contaminant. A series of intermediate-scale experiments were conducted to examine the effectiveness of permanganate for in situ chemical oxidation of organic liquid (trichloroethene) trapped in heterogeneous porous media. The results of these experiments have improved researchers' understanding of the effectiveness of ISCO for heterogeneous systems and will help enhance the design and implementation of ISCO.