Treatment of RO Concentrate for Enhanced Water Recovery from Wastewater Treatment Plant Effluent

Due to continual deterioration of surface water quality and increased water scarcity, water reclamation of the treated effluent has become a widely accepted strategy for sustainable water supply in urban areas. Reverse osmosis (RO) is a reliable and essential water reclamation technology for producing high-quality water for reuse. The RO concentrate, which is the waste stream produced from the RO process, is volumetrically substantial and contains environmentally harmful substances and therefore can cause severe environmental impacts if disposed of to receiving water bodies. Several technologies are available for further treatment of RO concentrate to reduce its volume, remove its total dissolved solids (TDS) and total organic carbon (TOC) and reclaim it for additional water recovery. This chapter presents a review of RO concentrate quality and various technologies for treating RO concentrate originated from municipal wastewater treatment plant. The technologies discussed include mineral recovery, electrochemical desalting and removal of TOC through adsorption, coagulation and oxidative degradation. Other alternative strategies including the emerging technologies for increasing water recovery rate from water reclamation plant are also proposed.