title: Adapting a denitrifying biocathode for perchlorate reduction.
abstract: Perchlorate is widely used as a propellant in the aerospace and defense industries, and is of environmental concern due to its high mobility and inhibiting effect on thyroid function. An ideal treatment approach is bioreduction to chloride via dissimilatory perchlorate-reducing bacteria (PCRB). PCRB are ubiquitous in the environment, and are mainly facultative anaerobes and denitrifiers. Previous research suggests that PCRB may grow using a cathode as an electron donor, although this research was performed in a half cell with exogenous electron shuttles. We investigated a functioning MFC with a denitrifying biocathode for perchlorate reduction, as a means to confirm the existence of biocathode-utilizing PCRB and the possibility of perchlorate remediation without added shuttles. The biocathode was initially run with 20 mgN/L nitrate. The perchlorate concentration was increased stepwise from 0.1 mg/L to 20 mg/L, while the nitrate concentration was decreased from 20 mgN/L to 5 mgN/L. The maximum perchlorate removal was 12 mg/L-d, contributing 64% to the 0.28 mA produced by the cell. Given the lack of soluble electron donor in the medium, the extent of perchlorate reduction, and the improvement of perchlorate reduction over time, these tests strongly suggest PCRB are utilizing the cathode as an electron donor without exogenous electron shuttles.
authors.affiliation: Department of Civil Engineering and Geological Science, University of Notre Dame, Notre Dame, IN 46556, USA. cshea1@nd.edu
authors.forename: Caitlyn
authors.initials: C
authors.lastname: Shea
authors.forename: Peter
authors.initials: P
authors.lastname: Clauwaert
authors.forename: Willy
authors.initials: W
authors.lastname: Verstraete
authors.forename: Robert
authors.initials: R
authors.lastname: Nerenberg
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D004560:Electricity; D004566:Electrodes; D009566:Nitrates / Q000302:isolation & purification; D009584:Nitrogen / Q000378:metabolism*; D010084:Oxidation-Reduction; D010472:Perchlorates / Q000302:isolation & purification / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D009566:Nitrates; D010472:Perchlorates; D014874:Water Pollutants, Chemical; D009584:Nitrogen; C494474:perchlorate