At a special meeting this week of the Orange County Water District (OCWD) board of directors, the board voted to move forward with construction of the 30-million-gal-per-day (mgd) initial expansion of the Groundwater Replenishment System (GWRS). The overall budget is set at $156.2 million and the project will create an additional 31,000 acre-ft per year (AFY) of new water supplies to serve north and central Orange County. This would bring the total production of the GWRS to 103,000 AFY, enough water for 850,000 people. Construction is estimated to be completed in September 2014.
The GWRS, a joint project of the OCWD and Orange County Sanitation District (OCSD), takes highly treated wastewater and purifies it through a three-step process that includes microfiltration, reverse osmosis and ultraviolet light with hydrogen peroxide, resulting in near-distilled quality water. It is the world’s largest advanced water purification facility of its kind, currently producing up to 70 million gal of new water every day.
The facility has garnered more than 20 awards, including the American Society of Civil Engineers 2009 Outstanding Civil Engineering Achievement Award for the year’s most outstanding national engineering project, and the Stockholm 2008 Industry Water Award for the year’s most outstanding international water project.
The GWRS enhances existing water supplies by providing a reliable, high-quality source of water to recharge Orange County’s groundwater basin and protect it from further degradation due to seawater intrusion. It also has provided peak wastewater disposal flow relief and indefinitely postponed the need for OCSD to construct a new ocean outfall by recycling wastewater flows that would otherwise be discharged to the Pacific Ocean.
The basin, which is larger than the largest reservoir in Southern California, has helped Orange County weather multi-year droughts by stabilizing local water supplies and costs to ratepayers.
The GWRS currently consists of three major components: the 70-mgd Advanced Water Purification Facility (AWPF) and pumping stations located in Fountain Valley; a 14-mile pipeline adjacent to the Santa Ana River connecting the treatment facilities to existing recharge basins in the cities of Anaheim and Orange; and the expansion of an existing seawater intrusion barrier in the cities of Fountain Valley and Huntington Beach.
The GWRS Expansion will entail construction of 30-mgd additional treatment facilities at the AWPF site in Fountain Valley. Additional microfiltration, reverse osmosis and ultraviolet light treatment equipment will be purchased and installed. In addition, pumps, electrical equipment and additional post treatment systems are required. A significant portion of the infrastructure has already been constructed to accommodate the expansion, including underground piping, pump stations and electrical systems.
In addition to creating a reliable local source of water, the project reduces the amount of wastewater discharged to the Pacific Ocean, preserves the country’s coast and provides these benefits with fewer greenhouse gas emissions than importing water.
Source: Orange County Water District
