AWWA MTC69672

The City of Sand City, California is constructing a desalination facility utilizing seawater drawn from beach wells to provide a local supply of water to meet the needs of the City's future growth. Numerous seawater desalination facilities are in the planning, piloting, or demonstration stages in California; however, the Sand City facility is the first to be permitted in California under the current surface water treatment regulations and to receive approval from the California coastal commission as a permanent municipal water treatment facility. The City took a conservative approach to securing approval from the Department of Public Health and the Coastal Commission. Specifically, the following measures were employed to avoid complications in the permitting process: use of beach well intakes to avoid concerns of entrainment and impingement associated with open ocean intakes; use of energy recovery devices and high efficiency positive displacement pumps to reduce the energy use, carbon footprint, and operating costs of the facility; use of subsurface brine discharge wells to avoid the risk of brine toxicity impacts associated with ocean outfalls; and, selection of a treatment process providing 2-log units of additional removal or inactivation of viruses, Giardia, and Cryptosporidium, above the highest level required under California regulations. This paper presents the approval process for both the Department of Public Health and the Coastal Commission, and discusses specific concerns addressed during the permitting, such as the use of NSF-approved materials compatible with seawater, acceptance of the German validation testing for UV units, and the monitoring of conductivity as a surrogate for pathogens in the RO permeate. Includes tables, figure.