West Basin owns the C. Marvin Brewer Desalter Facility (Desalter) which began operating in July 1993. The Desalter was built on a site owned by California Water Service (CWS) in the City of Torrance where it removes chloride from groundwater impacted by seawater intrusion in the West Coast Groundwater Basin (WCGB). The Desalter was initially intended to be a five year pilot program to determine if brackish water could be economically treated to drinking water standards.
The Desalter is an approximately 1 million gallon per day (MGD) potable water facility which originally used two wells to pump brackish water from a saline plume remaining within the WCGB and treats the water using cartridge filters and reverse osmosis (RO). West Basin is allowed by Water Replenishment District of Southern California (WRD) to pump groundwater up to 2,000 acre-feet per year (AFY) per a court approved intervention to the Basin adjudication judgement in 1992. The treated water from the Desalter is blended with potable water, stored on the CWS site in a 5 million gallon storage reservoir, and then delivered to the distribution system. Under the terms of an agreement with CWS, West Basin reimburses CWS to operate and maintain the Desalter.
In 2005, the original two wells were replaced with one, more productive well. The new well had an original pumping production of approximately 1,200 gallons per minute (gpm) or 2,000 AFY from the saline plume in the Merged Lynwood-Silverado Aquifer. Over the last decade, available yield from the well has reduced, largely due to clogging of the aquifer and corrosion of the well pump. Recently the well has been redeveloped.The Desalter consists of cartridge filtration, reverse osmosis (RO), decarbonation, and blending. Chemical dosing includes antiscalant, liquid chlorine (sodium hypochlorite), and sodium hydroxide (caustic). The RO concentrate from the Desalter is discharged to the sewer under an industrial permit from Los Angeles County Sanitation Districts (LACSD). The concentrate is stored in a tank on site during the day for release at night. There is no extra capacity for discharge under the current permit.
The Desalter process