Fuzzy Filter: The Right Path for Graton Community Services District

The Graton Water Resource Recovery Facility (WRRF) in Sonoma County, Calif., is owned and operated by Graton Community Service District (GCSD). GCSD was mandated in 2004 to upgrade its 1979 secondary aerated lagoon to tertiary discharge standards. Before considering the most economical upgrade option for GCSD, Lescure Engineers (Santa Rosa, Calif.) evaluated the biological treatment capacity of the existing lagoon system. It determined that the lagoons have sufficient capacity to deliver effluent meeting the numerical BOD limit for tertiary effluent. Lescure Engineers helped GCSD to save significant capital and operating cost by keeping the existing secondary treatment system and installing a new tertiary treatment system.