Biological reduction of nitrate and perchlorate in brine water using up-flow packed bed reactors.

Denitrifying up-flow packed bed bioreactors (UPBRs) were evaluated for their capacity to simultaneously remove nitrate and perchlorate from ion exchange regenerant brines. A continuous-flow UPBR, which was inoculated with denitrifying bacteria obtained from a municipal wastewater plant, completely removed perchlorate as well as nitrate in conditions of up to 10% salinity. When nitrate and perchlorate were added to the UPBR, they were removed immediately. To investigate factors that affected the contaminant removal, acetate (as an electron donor) and sulfate (as a competing electron acceptor) were added at different salinities. Lower carbon loading decreased the nitrate and perchlorate reductions, but increased sulfate loading did not decrease the reductions of nitrate and perchlorate. In conclusion, the UPBR is a useful and powerful technology that simultaneously removes nitrate and perchlorate in brine.