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In late 2005, the Racine Water Utility successfully commissioned operation of a 50 MGDimmersed ultrafiltration (UF) membrane plant. As utility staff and other stakeholders gainedexperience and insight into the operation of this completely new treatment process, variousopportunities to improve on the installed system and on the proposed operation proceduresbecame apparent and necessary. These improvements have reduced membrane fouling, reducedchemical cleaning costs, reduced energy costs and have increased treatment capacity. This paperpresents the results of the on-going improvements to the Racine UF facilities.During 2008, Racine staff conducted a full-scale testing program to evaluate the impact ofconverting the pretreatment coagulant from ferric sulfate to polyaluminum chloride to reduce ironfouling of the membranes. Testing results demonstrated a significant improvement in membranepermeability, reduced trans-membrane pressure, lowered permeate pump energy use, andlengthened chemical clean-in-place intervals.Full-scale testing over several months also supported decreasing the frequency for membranechlorine maintenance cleans from daily to weekly with no impact to the membrane performance.This modification has reduced sodium hypochlorite chemical costs by nearly 50% and increaseddaily production time and net permeate capacity for the system.Both the membrane supplier and utility staff made physical modifications to the commissionedmembrane system during the first two years of operation to substantially improve operations.Modifications to the vacuum prime system has reduced the time required to perform the Staterequired 3/day integrity testing, thereby increasing the daily net production time for eachmembrane train by close to 1 hour. In addition, revamping of the permeate vacuum systemlowered electrical costs and reduced preventative maintenance activities and costs. Otherchanges to standard operating procedures and PLC programming have lowered fouling rates andreduced system alarms and warnings. Includes figures.

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Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 9File Size: 1 file , 940 KB