Hold the Salt: Innovative Treatment of RO Concentrate

Reverse osmosis (RO) membranes are currently used to reduce total dissolved solids (TDS) from brine surface or ground waters, secondary treated effluent or sea water; however the disposal of the concentrate flows from these systems can present a significant hurdle for many applications. Recently there have been new developments for the treatment of RO concentrate. This paper identifies potential concentrate treatment options and discusses implementation issues, cost considerations, and current technology. The concentrate treatment options considered include: discharge to surface water, land application, deep-well injection, electrodialysis/electrodialysis reversal, Vibratory Shear Enhanced Processing (VSEP), precipitative softening with reverse osmosis, High Efficiency Reverse Osmosis (HERO™), evaporation ponds, and mechanical evaporation.A case study will be presented for the Luggage Point Advanced Treatment Plant in Brisbane (Queensland, Australia), where treatment wetlands are being proposed as a sustainable solution to RO concentrate management. Pilot trials are currently underway and results will be presented.