AWWA MTC69663

In 2007, The Irvine Ranch Water District (IRWD) took steps to minimize concentrate disposal for its deep aquifer treatment system by further treating the brine stream with another stage of nanofiltration, naming the plant the Concentrate Treatment System (CTS). In 2008, with a focus on optimizing operating costs at their reverse osmosis groundwater desalter, IRWD turned its attention towards minimizing the concentrate stream through an antiscalant procurement process developed specifically for minimizing pretreatment chemical costs while simultaneously increasing operating recovery and decreasing concentrate disposal volumes. As part of the Irvine Desalter Project, the Potable Treatment Plant (PTP) treats approximately 3 mgd of brackish groundwater with reverse osmosis before bypass blending and product stabilization. The plant has operated successfully for over a year, using antiscalant and sulfuric acid as chemical pretreatment to prevent precipitation of sparingly soluble salts (scale) in the tail end of the system. In an effort to reduce O&M costs, IRWD employed a competitive antiscalant procurement process that required prospective suppliers to provide proposals for the antiscalant product, dose, RO feed pH setpoint, and operating recovery. Proposals were evaluated based on total annual cost of antiscalant, sulfuric acid, and concentrate disposal. The lowest cost proposal was demonstrated on the pilot scale for 60 days to ensure acceptable performance before implementation on the full scale RO trains. This paper discusses the antiscalant procurement process employed by IRWD and the results of this competitive bid process. Includes 3 references, tables, appendices.