AWWA JAW56577

The Idyllwild Water District (IWD) and Pine Cove Water District (PCWD) are small California groundwater systems drawing from soft, mildly acidic source waters with high carbon dioxide content and dissolved inorganic carbon concentrations. After both systems exceeded one or both of the lead and copper action levels in 1993 and 1994, IWD and PCWD investigated aeration as a way to increase pH and replace inhibitor or other chemical additions. Following pilot-testing, full-scale deep bubble aeration systems went online in both water districts in October 1998. By January 1999, IWD and PCWD easily met the lead and copper action levels. In addition, radon (Rn) samples from PCWD showed a 99% reduction in Rn levels, ensuring compliance with upcoming Rn regulation. Furthermore, the use of aeration for corrosion control simplified treatment and improved water quality in most respects. When source water chemistry is appropriate, aeration treatment offers a simple and inexpensive substitute for chemical dosing for corrosion control of lead and copper. Many smaller water systems struggle with operating chemical feed systems and selecting chemical dosages for phosphate corrosion inhibitors. For a modest initial capital investment and with good planning, water systems with the appropriate chemistry can use aeration to take the place of chemical dosing for corrosion control while removing Rn beyond any regulatory proposals. The end result is cost-effective, operator-friendly treatment that can simultaneously resolve other potential water quality issues. Includes 33 references, tables, figures.