Water Quality and Treatment

Golden State Water Company (GSWC) operates 37 water systems throughout California. All systems have complied with the Lead and Copper Rule (LCR) since the rule was promulgated in 1991. Even though GSWC’s systems have been in compliance, the company took the proactive step to evaluate the potential for enhanced corrosion control to improve water quality to customers and reduce leaks and failures. Corona assisted GSWC to 1) evaluate the corrosivity of existing and potential new source waters and determine feasibility of further corrosion control, 2) prioritize and rank the water systems that may benefit from enhanced corrosion control treatment, 3) develop recommendations on potential corrosion control treatment options for systems that may benefit from additional corrosion control, and 4) test various corrosion control options at the bench-scale. Corona also worked with GSWC to develop guidelines to evaluate how bringing new sources of supply online impacts corrosion control.

Corona conducted a treatment study for 27 different wells Cr(VI)-impacted wells operated by California Water Service (Cal Water) and found strong-base anion exchange (SBA-IX) or reduction-coagulation-filtration (RCF) to be the most cost-efficient options. As a result, Cal Water procured nine full-scale SBA-IX treatment facilities. Corona conducted pilot testing to optimize SBA-IX performance in terms of resin selection, contact time, and brine regeneration strategies, which was supported in part by a $5 million research grant from the Proposition 50 Chapter 6(b). Corona also conducted RCF pilot testing that showed Cr(VI) reduction with ferrous could proceed ~20-times faster than was originally thought.

Corona assisted Sammamish Plateau Water and Sewer District with development of a monitoring and response plan including treatment and non-treatment alternatives with relevant design criteria and costs to address PFAS contamination in several groundwater wells. Corona is currently engaged to provide response support for the occurrence of PFAS in the District’s groundwater wells including monitoring for shorter chain compounds such as GenX and Adona.