Abstract
The United Nations International Decade for Action on Water for Sustainable Development (2018-2028) recognized the importance of water to sustainable development and the eradication of poverty and hunger. It voiced alarm over the worsening of issues such as access to clean water, water scarcity, and wastewater as a result of increasing populations and altered climates. One of the most promising solutions to the water shortage is desalination, which can increase the available water supply beyond the currently possible limit. In this study, we analyze the performance of a unique hybrid self-regeneration ion exchange and reverse osmosis (HSIX-RO) system for the desalination of brackish groundwater. In the pretreatment step for protecting RO membrane fouling, the traditional homogenized strong acid cation exchanger (Purolite C100) and shallow shell structured strong acid cation exchanger (Purolite SSTC65) were compared for their efficiency in removing hardness cations from brackish groundwater. The fixed-bed column study concluded that C100 and SSTC65 can treat brackish water containing 250 mg L1 Ca2+and 10,000 mg L1 NaCl at approximately 80 and 76 bed volumes (BVs), respectively. Studying the efficiency of RO system, it has % RO recovery of >70 % at an optimized pressure of 120 psi. An upscale self-regeneration ion exchange and RO system, i.e., HSIX-RO, that can be applied for a pilot- scale study was proposed. This proposed study suggested that HSIX-RO can be suited for the desalination of brackish groundwater with minimum use of an additional salt and can be self-sustained using an automated control. It was noted that the HSIX-RO system cannot be effectively applied to groundwater (TDS <5000 mg L1) nor seawater (TDS >30,000 mg L1) contained high Ca2+and Mg2+due to low regeneration efficiency and short length service runs, respectively