Electrochemical Stimulation of Microbial Perchlorate Reduction

Authors

J. Cameron Thrash, University of California, BerkeleyFollow
J. Ian Van Trump, University of California, Berkeley
Karrie A. Weber, University of Nebraska-LincolnFollow
Elisabeth Miller, Southern Illinois University Carbondale
Laurie A. Achenbach, Southern Illinois University CarbondaleFollow
John D. Coates, Lawrence Berkeley National LaboratoryFollow

Date of this Version

2007

Citation

Environ. Sci. Technol. 2007, 41, 1740-1746; DOI: 10.1021/es062772m

Comments

This article is a U.S. government work, and is not subject to copyright in the United States.

Abstract

As part of our studies into the diversity of dissimilatory perchlorate reducing bacteria (DPRB) we investigated the reduction of perchlorate in the cathodic chamber of a bioelectrical reactor (BER). Our results demonstrated that washed cells of Dechloromonas and Azospira species readily reduced 90 mg L^-1 perchlorate in the BER with 2,6- anthraquinone disulfonate (AQDS) as a mediator. No perchlorate was reduced in the absence of cells or AQDS, or in an open-circuit control. Similar results were observed when a natural microbial community was inoculated into a fed-batch BER. After 70 days of operation, a novel DPRB, strain VDY, was isolated which readily reduced perchlorate in a mediatorless BER. Continuous up-flow BERs (UFBERs) were seeded with active cultures of strain VDY, and perchlorate at a volumetric loading of 60 mg L^-1 day^-1 was successfully removed. Gas phase analysis indicated that low levels of H₂ produced at the cathode surface through electrolysis may mediate this metabolism. The results of these studies demonstrate that biological perchlorate remediation can be facilitated through the use of a cathode as the primary electron donor, and that continuous treatment in such a system approaches current industry standards. This has important implications for the continuous treatment of this critical contaminant in industrial waste streams and drinking water.