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<br />OTHER PROJECTS <br /> <br />In coastal regions dependent on groundwater, salt <br />water intrusion has proven to be an impediment to <br />water quality. The Orange County Water District <br />(OCWD), in conjunction with the Orange County <br />Sanitation District (OCSD) has been recycling water <br />and injecting it into aquifers to provide a barrier <br />against sea water intrusion since 1975. When coastal <br />groundwater basins are pumped below sea level, salt <br />water is drawn inland and can contaminate coastal <br />water supply wells. At the OCWD's Water Factory <br />21,10,000 acre-feet a year (15 mgd) of secondary <br />treated water undergoes tertiary and advanced treat- <br />ment, including a reverse osmosis process. <br /> <br />Water Factory 21 was the first large-scale, reverse <br />osmosis plant in the world and carried a total <br />construction cost of almost $21 million. Its recycled <br /> <br />water is blended wilh 5 mgd of deep well water and <br />injected into the domestic groundwater supply to <br />raise the water table and prevent saltwater intrusion. <br />About 15 percent of this J>ended water, priced around <br />$306 an acre-loot, ends up in the municipal water <br />supply. <br /> <br />In 1998, OCWD and OCSD again joined forces and <br />proposed the Groundwater Replenishment System, <br />a plan similar to Water Factory 21 but with a much <br />higher output. The proposed project will recharge <br />aquifers in Fountain Valley with 100,000 acre-feet of <br />advanced treated recycled water. The project, <br />estimated to begin construction in 2003 and be com- <br />pleted in 2020, could cost $400 million and would <br />recycle 40 percent of the wastewater produced by <br />Orange County homes (about 100,000 acre-feet of <br /> <br />RECYCLING WASTE WATER <br /> <br />Orange County water officials want to channel treated waste water into <br />underground water supplies, potentially holding down water costs and meeting <br />increasing demand expected in coming decades. <br /> <br /> <br />OClear and odorless waste <br />water is rather salty and must <br />be treated to make it drinkable. <br /> <br />Treated <br />waste water <br /> <br />o Microfiltratlon <br />removes larger <br />substances such as <br />viruses and bacteria. <br /> <br />o Revers~ <br />osmosIs <br />removes particles """. <br />at the molecular <br />level and gets rid <br />of the salty taste. <br /> <br /> <br />~ - <br /> <br />Waste water: <br />80 percent <br />discharged into <br />the sea. <br /> <br />- <br /> <br />The O.c. water district <br />wants to salva~e some <br />of the 245 million gallons of <br />treated waste water <br />discharged into the <br />ocean every day. <br /> <br />A Treated water <br />U sent to holding <br />pools and the Santa <br />Ana River bed. <br /> <br />~. <br />.. <br />~~r <br /> <br />A Purilied wate1'rs' <br />\:I PMnlped to tile <br />sy,rfa(e and could be <br />,treated with chlorin'-: <br />before it shows u~fin ". <br />our house. ' . . <br />. '. <br /> <br />17 <br />