Processing of surface and ground water by hydrostatic pressure-driven membrane techniques: design and economic aspects

摘要

In recent years, membrane-based ultrafiltration (UF) and reverse osmosis (RO) have become popular worldwide as possible alternative methods to conventional ion exchange and clarification processes for the production of potable water. The performance of UF and RO membranes was evaluated for treatment of surface and ground water from Prakasam District of Andhra Pradesh, India; namely, jagarlamudi well water (JWW), jagarlamudi pond water (JPW), veerannapalem old pond water (VOPW), and veerannapalem new pond water (VNPW). Pilot-scale UF and RO systems were built indigenously by incorporating commercial hollow fiber polyacrylonitrile UF and thin film composite polyamide RO modules, respectively. Operating parameters such as feed concentration, pressure, and cross-flow velocity were varied to study their effect on membrane performance. Effect of fouling on flux and rejection characteristics of the membrane was evaluated. RO membrane exhibited a rejection of 96.4% for JWW and VOPW feeds with reasonable flux of 42.5 and 48 L m~(-2) h~(-1), respectively, whereas, UF experiments with JPW and VNPW feeds revealed corresponding turbidity rejections of 95.6 and 98.2%. A mathematical model was developed for commercial RO system to simulate the process for establishing optimum operating conditions. A comparison of UF and RO processes for this application is presented along with useful details of equipment list, process flow diagram of commercial membrane plant, schematic of compact hollow fiber pilot plant, and detailed estimation of operating costs.