AWWA ACE60080

Irvine Ranch Water District (IRWD) is located in Southern California, a semi-arid area with limited water resources. IRWD and their project partner Orange County Water District (OCWD) have made a commitment to implement reverse osmosis and air stripping technologies to clean up the Irvine subbasin and develop a new water supply for the area. The Irvine Desalter Project (IDP) will extract and treat groundwater to: develop a local water supply; intercept, contain, and treat groundwater with high concentrations of salts (TDS) and nitrates; and, accept and treat for volatile organic compounds (VOC) removal contaminated groundwater from the former El Toro Marine Corps Air Station. IDP is composed of two separate components: a non-potable system which treats VOC contaminated groundwater and a potable system which treats groundwater from wells located outside the VOC plume. The potable system uses reverse osmosis (RO) to remove TDS and nitrates. The non-potable system treats VOC contaminated water using RO and air stripping with granulated activated carbon (GAC) off-gas treatment. Typical of most inland desalting projects, brine disposal is a major challenge. Downstream wastewater treatment plants do not want to accept the brine due to its high salt content. IRWD is currently analyzing alternative disposal options including construction of a regional brine line to a nearby ocean outfall. The completed project will not only halt the spread of contaminated groundwater but will also provide a new, local, cost-effective water supply. This paper outlines the steps IRWD and OCWD have taken to make this project a reality. Details are provided on: pilot testing; full scale treatment plant design; project costs; and, project funding. Includes tables, figures.