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This research project evaluated the feasibility of retrofitting a custom designedmembrane system as a final separation process in a conventional water treatmentplant (WTP). This paper presents preliminary findings from pilot tests conductedat a water treatment plant located in Sheboygan, Wisconsin, which treats rawwater with conventional processes. Settled water was treated, in lieu of granularmedia filtration, by an ultrafiltration (UF) pilot plant. To date, membraneapplications for drinking water have involved proprietary membrane systems anddesigns, and generally have been limited to facilities with capacities on theorder of 30 million gallons per day (mgd) or less due to high construction costsand scale up issues. A custom approach to membrane system design described hereincan offer significant advantages to utilities which: must comply with morestringent drinking water regulations; want to maximize the return on theinvestment in existing water treatment facility components (e.g., conventionalpretreatment process units including granular filters and associated concretestructures); and, have treatment capacities greater than 30 mgd and have notconsidered the use of membranes due to the high installed cost of the modular,proprietary system designs currently available. Two approaches to custom membranesystem designs are discussed: a gravity-driven process where membranes may beimplemented into the existing hydraulic gradeline of a water treatment plant;and, a pumped approach that is similar to existing proprietary systems, butoffers the benefits of a custom design for maximizing the use of existinginfrastructure and lower operating pressure. The pilot unit met the criteria forchemical cleaning frequency greater than 30 days and water quality performancewhen operated under head of 20 feet of water with settled water at a flux of 24gfd and recovery of 90 percent. This result allows reuse of the filter boxes andfilter capacity increase of at least 15 percent. This result also offers aneconomically viable membrane alternative. Includes 11 references, tables, figures.

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Edition: Vol. - No. Published: 05/01/2001 Number of Pages: 18 File Size: 1 file , 460 KB