Full Description

The Groundwater Replenishment (GWR) System in Orange County, California is an indirect potablereuse project that will produce 70 million gallons per day (mgd) of water initially with anultimate capacity of 130 mgd for groundwater recharge and groundwater basin protection fromseawater intrusion. Sponsored by the Orange County Water District (OCWD) and the OrangeCounty Sanitation District, the GWR System will be comprised of three major components:the Advanced Water Purification Facility (AWPF) and pumping stations; a major pipelineconnecting the treatment facilities to existing recharge basins; and, an extension of the existingseawater intrusion barrier. The AWPF will treat clarified secondary effluent, currentlydischarged into the ocean, using microfiltration (MF), reverse osmosis (RO), and advancedoxidation (ultraviolet light treatment with hydrogen peroxide). The product water will bepumped to injection wells and recharge basins, where the water will naturally pass through theground and blend with Orange County's other sources of groundwater. Besides providing a new,local source of water, the project will eliminate the need for an additional outfall to the ocean,and will improve the water quality of the Orange County groundwater basin.To maintain the seawater intrusion barrier during AWPF construction, OCWD has constructed anew MF system, installed new RO membranes, and constructed a new ultraviolet (UV) lighttreatment system to produce 5 mgd of injection water until AWPF construction is complete,which is estimated to be in August 2007. This project, known as GWR System Phase 1, consistsof a submersible MF system, the use of polyamide RO membranes, and a low-pressure high-output(LPHO) UV light with hydrogen peroxide advanced oxidation system.Once the GWR System Phase 1 construction and startup was complete, a series of water qualitytests was performed on the system. The GWR System Phase 1 successfully completed a 30-dayacceptance test and met the water quality requirements set forth in the California Regional WaterQuality Control Board Producer/User Water Recycling permit. Since June 21, 2004, approximately 5 mgd of GWR System Phase 1 product water has been used to supplementsources to protect OCWD's groundwater basin against seawater intrusion. Although pilot testingwas performed on the MF and RO membranes prior to constructing the GWR System Phase 1,this is the first opportunity to operate the system for an extended period of time prior toimplementation of the 70 mgd membrane plant.This paper presents current MF and RO effluent quality and performancedata as compared to permit requirements, the 30-day acceptance test data and criteria, and pastcellulose acetate RO membrane data from the Water Factory 21 facility. Includes 8 references, tables, figures.

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Edition: Vol. - No. Published: 03/01/2005 Number of Pages: 20File Size: 1 file , 540 KB