West Basin Municipal Water District's (WBMWD) Ocean water Desalination Pilot Plant Program is testing the capabilities of microfiltration (MF) pretreatment in series with a spiral wound reverse osmosis (RO) system. It is developing data to determine the optimum operating conditions and cleaning requirements for microfiltration operating on ocean water, as well as the ocean water reverse osmosis process operating on microfiltration filtrate. Once the study is complete, the data will be used to develop updated cost assessments of ocean water desalination. The objectives of the Ocean water Pilot Test Program are: to determine the optimum membrane operating flux and in-situ membrane cleaning frequency for a MF system operating on Southern California coastal ocean water; to investigate cleaning formulations and techniques for removal of contaminants found in ocean water, which foul the MF membrane; to determine the optimum membrane operating flux and in-situ membrane cleaning frequency for an ocean water RO system operating on MF filtrate; to investigate cleaning formulations and techniques for removal of contaminants found in microfiltered ocean water, which foul RO membranes; to characterize the MF backwash and RO concentrate streams to develop data suitable for evaluation of waste stream disposal options; and, to develop design and operating parameters based on the above data to assess cost of ocean water desalination for the purpose of production of drinking water by MF/RO. Includes tables, figures.