Regeneration of ion-exchange resins with sodium chloride produces brine containing high concentrations of nitrate, perchlorate, or both. Reverse osmosis also creates similar brines. The presence of these contaminants makes it unacceptable toreuse the brines for regenerating ion-exchange resins or for disposal, such as the ocean. A hydrogen-based MBfR can be used to reduce nitrate and perchorate from the brine.Nitrate and perchlorate are nor removed from water using conventional treatment involving coagulation, flocculation, sedimentation, and filtration. Advanced treatment techniques, such as reverse osmosis, ion exchange, membrane filtration, and electrodialysis, are effective for removing both anions, but are significantly expensive and produce waste brines containing hight levels of the target contaminants, in this case perchlorate and nitrate. To reduce the requirments for salt and spent-brine disposal, several procedures for detoxifying and reusing spent brine have been developed. Among them, biological reduction may provide the most suitable alternative, as nitrate and perchlorate are microbiologically reduced to innocuous N2 and Cl; respectively. The hydrogent-based MBfR, which has been proven for direct treatment of water contaminated with nitrate, perchlorate, and other oxidized contaminants, also can be valuable for removing nitrate and perchlorate from brines produced from direct treatment by ion exchange or reverse osmosis.
|Original language||English (US)|
|State||Published - Jul 27 2005|