AWWA WKICO66056

This powerpoint presentation explores using a hydrogen-based membrane biofilm reactor (MBfR) for simultaneous bio-reduction of multiple oxidized contaminants in groundwater. Drivers for using hydrogen gas (H₂) as an electron donor are listed, along with the benefits of using autotrophic bacteria. A schematic of a laboratory MBfR system is provided, and the following topics are presented: an explanation of "Counter Diffusion" in the MBfR; CLSM of biofilm formed in MBfR; reductions of nitrate, perchlorate, and selenate by MBfR; the reduction reactions and the immediate reduction efficiencies for the contaminants in MBfRs acclimated to nitrate; Microorganisms in the perchlorate and nitrate system; reduction of perchlorate by an MBfR - a long-term test without nitrate present; simultaneous reduction of nitrate and perchlorate in a real groundwater; and, Simultaneous Reduction of Nitrate and Selenate - changing H₂ pressure to improve reduction, and changing Se(VI) loading to obtain 100% reduction. Includes 8 references, figures.