Abstract
The Eastern Municipal Water District, Perris, Calif., is a public water agency and community water system in western Riverside County that provides domestic and agricultural water, wastewater collection and treatment, and recycled water in a 555-mi2 service area with a population of 570,000. The district has three sources of water—water imported from the Metropolitan Water District of Southern California, local groundwater, and recycled water. One of the district's potable water sources includes the 20-mgd Perris Water Filtration Plant (PWFP), which operates at 96-98 percent recovery. After a planned expansion to 24 mgd, PWFP will generate up to 1 mgd of reject water. The district is currently conducting preliminary design to install a reject recovery facility to reclaim the reject water, which would otherwise be disposed to the sewer. This article details procurement and preliminary design evaluations to provide a low-pressure membrane treatment system to recover membrane reject water. The article also details the design and regulatory requirements for second-stage (reject) filtration to the clearwell based on implications of the US Environmental Protection Agency's Long Term 2 Enhanced Surface Water Treatment Rule.