AWWA MTC50248

The City of South Bend, Washington, is in the process of implementing low pressure membrane filtration as a process alternative to its existing 500 gpm in-line pressure filtration treatment plant. At the planning and design stages several issues related to the small size of the system were identified including the following: membrane system selection without extensive pilot testing; cost effective pilot testing to develop design criteria and satisfy State's requirements; maintain a competitive situation for membrane systems; redundancy requirements and their cost; coping with the non-modular nature of membrane systems for small capacities; cost effective backwash water disposal; staff training; and, obtaining grants and loans and implications for equipment procurement. Pilot testing was conducted at South Bend for four months using a microfiltration (MF) system and an ultrafiltration (UF) system. Despite the slight increase in pilot testing cost, two systems were tested with the goal to maintain a competitive situation at the time of system bidding. No significant fouling was observed for periods up to 35 days with the MF system, however chemical cleaning of the UF system was required approximately every two weeks. Includes 8 references, tables, figures.