Abstract: Reactive Permeable Barriers for In Situ Remediation of Groundwater

MARCUS, DONALD, L., and CHRIS L. BONDS, EMCON, Burbank, CA

Global competitiveness is an increasing concern in the United States, and the environmental remediation industry, long considered to be a sacred cow, is coming under increasing scrutiny. In light of shrinking budgets, and pressures to do the job better, and cheaper, EMCON is working on development of innovative in situ remediation technologies such as permeable reactive barriers. EMCON has recently installed permeable reactive barriers using continuous trenching equipment and an EMCON proprietary technology called Reactant Sand-Fracking. Continuous trenching enables the rapid installation of permeable barrier systems down to depths of about 30 feet below ground surface in unconsolidated materials. Reactant Sand-Fracking enables the installation of permeable reactive barriers by hydraulic injection into deep and fractured bedrock.

Concentrations of the chlorinated volatile organic compounds tetrachloroethene and trichloroethene and metals including hexavalent chromium are reduced by 90-99% by reaction in situ with zero valent iron media. The chlorinated volatile organic compounds are destroyed by abiotic hydrolysis reactions in a process called reductive dehalogenation and the metals are converted to reduced species and precipitated in situ. Reactive permeable barriers are one of the best demonstrated examples of passive in situ groundwater remediation technologies and EMCON is leading the way with new and more efficient ways of installing them in a variety of geologic environments with various types of contaminants. These new technologies provide hope for a future of cost effective and environmentally friendly remediation projects.

AAPG Search and Discovery Article #90935©1998 AAPG Pacific Section Meeting, Ventura, California