Geochemical optimization of in-situ chromate remediation.
Abstract Book, U.S. Department of the Interior Conference on the Environment and Safety, April 24-28, 1995. Washington, DC: U.S. Bureau of Mines, 1995 Apr; :60
The U.S. EPA is conducting a significant field test of innovative in-situ remediation for metal-contaminated ground water at the Elizabeth City, NC, Coast Guard Station. High concentrations of ground water chromate (Cr04-2) are being removed by placing a permeable metallic iron filing "reaction wall" in the plume's path to reduce Cr(VI) to insoluble Cr(III)-Fe(III) hydroxides. USBM Twin Cities Research Center is assisting EPA optimize this process by providing detailed microscopic characterization and geochemical interpretation of chromate reduction at the reaction wall. Key findings are that (1) chromate reductive remediation at iron filings follows a "corrosion-like" mechanism and (2) partial dissolution of aquifer material alumino-silicates is needed to buffer the contaminated ground water pH below 8, a range necessary for chromate reduction to occur. Current work is focused on (1) changes in the reaction wall with time in the aquifer plume and (2) investigation of secondary sorption or precipitation of Cr down gradient from the permeable reaction wall. .
Chromates; Metal-compounds; Metal-poisoning; Metals; Water-analysis; Water-sampling; Hydroxides; Silicates
Conference/Symposia Proceedings; Abstract
U.S. Bureau of Mines