Pilot study on renovation of subsurface water using a reverse osmosis desalting system

Like many cities of the world, Kuwait has seen a continuous rise in the subsurface water table. The impact of the water rise is manifested in flooded basements, surface ponding of water, cracks in buildings and damaged roads. A study carried out by the Kuwait Institute for Scientific Research (KISR) recommended drainage by deep wells to lower and maintain the subsurface water at a desired level. A large quantity of water needs to be permanently pumped for this purpose. Disposing of the pumped water as waste is a loss that Kuwait cannot afford in view of its meager, over-stressed and practically non-renewable natural groundwater resources. Since the quality of the pumped water is likely to prohibit any direct use, it is proposed to reduce its salt content using reverse osmosis (RO) technology. The desalinated water can then be used for lawn-watering, thus saving on the use of brackish groundwater supplied from other sources. RO is being used for desalting a variety of feedwater, but its use with subsurface water has not been investigated before in Kuwait. This water is different from natural groundwater in that it is partially contaminated. However, before large-scale implementation, it is essential to evaluate the performance of RO with the special biochemical characteristics of subsurface water. This paper outlines the result of a pilot plant study carried at KISR to investigate the viability and technical feasibility of using two types of RO configuration systems (i.e., SW and HFF) to desalinate subsurface water. The results indicate that both systems have technical and economic merits and can produce freshwater of high quality for agriculture, lawns and for emergencies at comparatively low cost.