AWWA MTC69672

The City of Sand City, California is constructing a desalination facilityutilizing seawater drawn from beach wells to provide a local supply of water to meet theneeds of the Citys future growth. Numerous seawater desalination facilities are in theplanning, piloting, or demonstration stages in California; however, the Sand City facilityis the first to be permitted in California under the current surface water treatmentregulations and to receive approval from the California coastal commission as apermanent municipal water treatment facility.The City took a conservative approach to securing approval from the Department ofPublic Health and the Coastal Commission. Specifically, the following measures wereemployed to avoid complications in the permitting process:use of beach well intakes to avoid concerns of entrainment and impingementassociated with open ocean intakes;use of energy recovery devices and high efficiency positive displacement pumpsto 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 impactsassociated with ocean outfalls; and, selection of a treatment process providing 2-log units of additional removal orinactivation of viruses, Giardia, and Cryptosporidium, above the highest levelrequired under California regulations. This paper presents the approval process for both the Department of Public Healthand the Coastal Commission, and discusses specific concerns addressed during thepermitting, such as the use of NSF-approved materials compatible with seawater,acceptance of the German validation testing for UV units, and the monitoring ofconductivity as a surrogate for pathogens in the RO permeate. Includes tables, figure.



Keywords: California; Seawater; Brines; State Regulations; Intakes; Outfalls; Monitoring; Conductivity; Pumps; Desalination