Optimize Brackish Groundwater: Treating RO Brine to Increase Recovery and Reduce Disposal Volume

AbstractThe Eastern Municipal Water District in Perris, Calif., recently completed brine treatment studies for the California Department of Water Resources and the US Department of Interior, Bureau of Reclamation. The studies investigated the cost of alternative process treatment trains to recover usable water from primary reverse osmosis (RO) brine and significantly reduce brine volume or achieve complete zero-liquid discharge. The studies included pilot-scale, bench-scale, and desktop evaluations of established and emerging technologies for brine treatment. Chemical softening of primary RO brine followed by a second RO process or electrodialysis reversal (EDR) is an established technology. Emerging technologies investigated included membrane distillation (MD), forward osmosis (FO), and seeded RO. A 50-gpm chemical softening process was operated for six months and provided feedwater to RO and EDR pilot units. MD and FO were tested at bench scale, and seeded RO was operated in a batch pilot plant. Capital...