AWWA ACE56246

Burgeoning population growth, scarcity of new freshwater sources, and an influx of proposals to use reclaimed water to augment potable supplies have put increasing pressure on the State of California to develop comprehensive criteria for indirect potable reuse via groundwater recharge. While the California Department of Health Services (DHS) began the process of developing criteria for both surface spreading and injection projects several years ago, DHS has intensified its efforts in the last year. The most recent draft criteria, released in 2001, include requirements that reflect current concerns over nitrogen compounds, unregulated emerging chemical contaminants such as endocrine disruptors and pharmaceuticals, and total organic carbon (TOC) limits. Disinfected filtered reclaimed water is the minimum allowed for surface spreading projects, although additional treatment may be necessary if soil aquifer treatment is ineffective. Additional treatment via reverse osmosis is required for all injection projects to insure organics removal. DHS is now considering requirements to allow recharge of 50 to 100 percent reclaimed water with controls that may include testing for tentatively identified compounds, advanced oxidation using ultraviolet radiation and hydrogen peroxide, in vivo toxicity testing, and lowering the TOC limit to 0.5 mg/L. The criteria will continue to evolve to address new issues or concerns as they arise. Includes table, figures.