Water > Project Case Study

Microfiltration Membrane Provides Sustainable Water Infrastructure

Wright-Pierce was retained by Aqua Maine Inc. to permit, pilot test, select equipment, and design the first membrane filtration facility for a public water supply in the state of Maine. The existing Mirror Lake source of supply was unfiltered and the facility was operating under a filtration waiver from the EPA. New requirements for disinfection byproducts and cryptosporidium under the Long-Term 2 Enhanced Surface Water Treatment Rule required consideration of either UV light or membranes for the source.

Following extensive pilot testing of treatment technologies including ultrafiltration and microfiltration membranes, Pall microfiltration membranes were selected for the facility. An addition to the existing facility was built for the new treatment system.

The 6.0 MGD facility design is sustainable in many ways. A full reprocessing of backwash wastes on-site results in “zero discharge.” The waste is treated with a membrane recovery system which dewaters the backwash stream before secondary dewatering in lagoons. Solar and photovoltaic panels offset 75,000 kWh of purchased electricity annually resulting in substantial energy savings.

The membrane technology requires a relatively small building footprint due to high filter loading rates. Large, south facing windows provide passive solar heating and natural lighting. The upgrade also included renovation to the SCADA system, pumping equipment and primary power gear and motor control centers in the existing facility.

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