AWWA MTC53665

As the need for potable water from non-potable sources increases around theworld, so does the need for a reduction in the cost of producing this water. Ofparticular concern are the life cycle costs such as operational labor costs,power costs, membrane replacement, consumable costs and the like.The traditional designs for seawater reverse osmosis (SWRO) membrane systems, while potentially capitalcost effective, are also a stumbling block for the reduction of the eventualoperational costs resulting from ineffective pre-treatment and, quite often, pooroperational perspectives. The idea of integrating different membrane technologies into a single entity is notnew. It has been tried, with moderate success, since the initial development ofmicrofiltration membrane technology. The largest problems seemed to be withthe selection of the membrane technology available, and their incompatibility withthe source water problems. The use of spiral wound ultrafiltration systems inconjunction with brackish reverse osmosis or nanofiltration is fairly common inthe ultrapure industry. These systems, however, do not suffer from the greaterfeed source contamination found in seawater applications. A new approach is now using a more effective hollow fiber ultrafiltration membrane technology that does not need some of the complex equipmentassociated with other designs, thereby simplifying the operational characteristicsof the system. It also provides a more effective barrier for the microbialcontamination that plagues many SWRO designs.This paper will examine the design of such a system, considering the capital costimpact as well as the benefits in regards to long-term operation and maintenancecosts. Other potential savings, such as power consumption reduction andequipment reduction, will also be addressed. Includes 3 references, figures.