NERENBERG RESEARCH GROUP

H₂-BASED MBfRs FOR BROMATE REDUCTION

Funding: Capitalization Fund

Project start: 1/2005

Publications and presentations:

Leon S. Downing and Robert Nerenberg (accepted). Kinetics of Microbial Bromate Reduction in a Hydrogen-Oxidizing, Denitrifying Biofilm Reactor. Biotechnology and Bioengineering.

K. Martin, L. S. Downing, S. J. Green, R. Nerenberg (2007). Microbial Ecology of Bromate Reduction in a Hydrogen-Oxidizing Biofilm. 4^th ASM Conference on Biofilms. March 2007, Quebec City. (Poster).

Leon Downing and Robert Nerenberg (2006). Bromate Reduction in a Hydrogen-Based, Hollow-fiber Membrane-Biofilm Reactor. Proceedings of IWA Biofilm Systems VI, Amsterdam. CD ROM.

Leon Downing and Robert Nerenberg (2006). Microbial Bromate Reduction in a Hydrogen-Based, Membrane Biofilm Reactor: Inhibitory Mechanisms. Proceedings of AWWA Annual Conference and Exposition, San Antonio TX 2006.

Bromate is produced from bromide ion (Br^-) during ozonation or advanced oxidation of drinking water, and is a suspected human carcinogen (Kurata 1992). Bromate is regulated as a disinfection by-product at 10 μg/l (Clark 2001), and pilot and full-scale drinking water studies show bromate can form at concentrations as high as 150 μg/l (Krasner 1993). Bromate management is important when ozonation and advanced oxidation processes are used for drinking water treatment (Butler 2005).

Denitrifying bacteria can co-metabolically reduce bromate to innocuous bromide (Hijnen et al. 1995). Bromate also can serve as a primary electron acceptor for some bacteria (van Ginkel et al. 2005b). Both cometabolic and dissimilatory pathways may be responsible for bromate reduction in a mixed microbial biofilm treating nitrate and bromate. Understanding the interplay of these two reduction pathways is critical in designing an efficient reactor to treat waters containing bromate.

Our research focuses on bromate reduction in a hydrogen-based membrane-biofilm reactor (MBfR). As part of this research, we are exploring the effect of environmental conditions on bromate reduction in an MBfR, exploring the microbial ecology of a mixed-culture, denitrifying, bromate-reducing MBfR, and isolating and phylogenetically characterizing bromate-reducing bacteria. This research provides fundamental insight into the mechanisms of biological bromate reduction, as well as practical insights for the application of a hydrogen based MBfR for treatment of bromate in drinking water.