This powerpoint presentation begins by providing a brief overview of the San Francisco Public Utilities Commission (SFPUC) system, including water quality data and ultraviolet (UV) design criteria. SFPUC completed separate pilot fouling studies in 2007 and 2008 related to unfiltered concerns with sand, sediment, and algae. The 2007 work was an initial effort to evaluate fouling and different lamp technologies. The 2008 work was conducted to verify fouling and evaluate different wiper technologies. The 2007 pilot objectives were to: determine fouling rates for LPHO, LPHOA, and MP lamps; provide feedback to UV lamp technology selection process; and, support completion of treatment facility design criteria and bid documents. The 2007 pilot conclusions indicated that: UV fouling is site-specific and water quality dependent; iron, calcium, and aluminum are consistently the predominant foulants; automatic wiping capability was one factor in comparing lamp technologies along with factors such as lamp and ballast replacement costs; and, medium pressure lamp technologies were recommended for wiper testing and implementation at full-scale. The 2008 pilot objectives were to: evaluate automatic wiping mechanisms in parallel; and, mimic full-scale conditions for several variables. The 2008 pilot procedure is presented, and conclusions indicated that: an automated sleeve wiping system is required for SFPUC's Hetch Hetchy (unfiltered) supply; fouling rates without wiping in the 2008 large-scale pilot were similar to what was found in the 2007 smaller pilot for Hetch Hetchy water; iron, calcium, and aluminum again were the predominant foulants; both automatic wiping technologies were effective during the 2008 test period; fouling is site-specific and water quality dependent and one of many factors in selecting an UV system; and, pilot work is recommended to understand the operational and maintenance implications of fouling. Includes tables, figures.
