The Orange County (Calif.) Water District's (OCWD) board of directors has ap-proved a joint development, operation and maintenance agreement with the Orange County Sanitation District (OCSD) for the Ground Water Replenishment System (GWR System).
The GWR System will use highly-treated waste water from OCSD and purify it to better than current drinking water quality through high-tech filtration processes, including reverse osmosis, which is used by many bottled water companies.
For 25 years, OCWD has purified sewer water to drinking water standards for injection into the ground water basin to keep seawater out of the underground drinking water supply. As Orange County continues to use more ground water, the GWR System will expand that process, providing a new source of water for the underground barrier as well as for OCWD's water portfolio.
The agreement spans 30 years and covers Phase One of the GWR System, which is scheduled for completion in 2007. Under the agreement, OCWD and OCSD will share equally the capital costs to build the project, while OCWD will pay for operations, maintenance and repairs once the system is operational.
Benefits to OCWD include 72,000 acre-feet per year of new water, enough to meet the needs of 140,000 Orange County families annually; less water to the ocean and OCSD benefits by not having to build another ocean outfall to handle increasing flows to the ocean.
According to OCWD general manager Virginia Grebbien, purified water developed through the GWR System provides an independent, locally controlled supply that diversifies OCWD's water supply portfolio; helps reduce the minerals in the ground water and reduces OCWD's dependence on imported water.
Once completed, the GWR System will take highly-treated sewer water that currently is released into the ocean and purify it through a redundant system including microfiltration, reverse osmosis and ultraviolet light with hydrogen peroxide advanced oxidation treatment, producing water similar in quality to bottled water. The purified water will become part of a seawater barrier and be pumped through a 13-mile pipeline to spreading basins in Anaheim where it will percolate into deep aquifers and blend with Orange County's other sources of ground water, following the same natural filtering path rainwater takes through the ground.