Desalting of subsurface water using spiral-wound reverse osmosis (RO) system: technical and economic assessment

Abstract Subsurface water rise is a major problem in Kuwait. The impact of this problem is manifested in surface water ponds, cracks in buildings, flooded basements and damaged roads. Dewatering this water of moderate salinity is necessary. Being in an arid area with very limited water resources, treatment and recycling of the subsurface water could be very important to a country like Kuwait. For this purpose, a pilot study was carried out by KISR to desalinate the subsurface water using the reverse osmosis (RO) technique. The main aim of this study is to assess the viability and economic feasibility of using RO technology. This paper outlines the results of over 8000 operating hours performance data of an RO plant utilizing spiral-wound membranes (SW) used to desalinate subsurface water with TDS of about 11,000 mg/1 and an economic feasibility evaluation. Results indicate that the (SW) RO system is a viable technique to desalinate this type of water. The improvements in TDS, COD and BOD were 99%, 96% and 42%, respectively. The economic feasibility evaluation indicates that the unit cost of desalting subsurface water by RO is 0.235 KD/m 3 (0.776 US$/m 3 ), which is considered to be economically feasible for a small-scale plant.