Reverse osmosis brine staging treatment of subsurface water

An earlier Kuwait Institute for Scientific Research (KISR) study on subsurface water rise problems in residential areas of Kuwait recommended drainage by deep wells to lower levels and maintain the subsurface water at a desired level. A large quantity of water needs to be permanently pumped for this purpose. The quality of the pumped water is likely to prohibit its direct use. Disposing of the water as waste is a loss that Kuwait cannot afford in view of its meager, over-stressed and practically nonrenewable natural groundwater resources. Therefore, experiments were conducted by KISR at the Kifan site to desalinate the rising subsurface water using reverse osmosis (RO) brine staging. Operation of these experiments lasted for about 5 months. The aim of these experiments was to test the technical feasibility of increasing the productivity of the tested RO systems using brine staging. This paper highlights the brine-staging concept and presents the data collected and an evaluation of the data. The data collected indicate that the average recovery obtained was 48%, availability of the brine staging RO unit was 97% and the increase in recovery using brine staging resulted in a significant reduction in the specific power consumption by about 37%.