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2015 URBAN WATER MANAGEMENT PLAN <br />The second step of the process consists of RO, semi - permeable polyamide polymer (plastic) membranes <br />that water is forced through under high pressure. RO removes dissolved chemicals, viruses and <br />pharmaceuticals in the water resulting in near - distilled- quality water that requires minerals be added back <br />in to stabilize the water. This process was used by OCWD from 1975 to 2004 at their Water Factory 21 <br />(W F -21) to purify treated wastewater from OCSD for injection into the seawater intrusion barrier. <br />The third step of the process involves water being exposed to high- intensity UV light with hydrogen <br />peroxide (H2O2) for disinfection and removal of any trace organic compounds that may have passed <br />through the RO membranes. The trace organic compounds may include NDMA and 1 -4 Dioxane, which <br />have been removed to the parts -per trillion level. UV disinfection with 1­12O2 is an effective <br />disinfection /advanced oxidation process that keeps these compounds from reaching drinking water <br />supplies. <br />OCWD's GWRS has a current production capacity of 112,100 AFY with the expansion that was <br />completed in 2015. Approximately 39,200 AFY of the highly purified water is pumped into the injection <br />wells and 72,900 AFY is pumped to the percolation ponds in the city of Anaheim where the water is <br />naturally filtered through sand and gravel to deep aquifers of the groundwater basin. The OC Basin <br />provides approximately 72 percent of the potable water supply for north and central Orange County. <br />The design and construction of the first phase (78,500 AFY) of the GWRS project was jointly funded by <br />OCWD and OCSD; Phase 2 expansion (33,600 AFY) was funded solely by OCWD. Expansion beyond <br />this is currently in discussion and could provide an additional 33,600 AFY of water, increasing total <br />GWRS production to 145,700 AFY. The GWRS is the world's largest water purification system for indirect <br />potable reuse (IPR). <br />6,2 Wastewater Description and Disposal <br />The City operates and maintains the local sewer system consisting of over 390 miles of pipeline, 7,630 <br />manholes, and two lift stations that connect to OCSD's trunk system to convey wastewater to OCSD's <br />treatment plants. OCSD has an extensive system of gravity flow sewers, pump stations, and pressurized <br />sewers. Collected wastewater is sent to OCSD's plants located in the Cities of Huntington Beach and <br />Fountain Valley. OCSD's Plant No. 1 in Fountain Valley has a capacity of 320 million gallons per day <br />(MGD) and Plant No. 2 in Huntington Beach has a capacity of 312 MGD. Both plants share a common <br />ocean outfall, but Plant No. 1 currently provides all of its secondary treated wastewater to OCWD's <br />GWRS for beneficial reuse. The 120 -inch diameter ocean outfall extends 4 miles off the coast of <br />Huntington Beach. A 78 -inch diameter emergency outfall also extends 1.3 miles off the coast. <br />Table 6 -1 summarizes the wastewater collected by the City and transported to OCSD's system in 2015. <br />No wastewater is treated or disposed in the City's service area as OCSD treats and disposes all of the <br />City's wastewater. <br />arcatli :.cam <br />d6EP 6-2 <br />