Full Description

This research project evaluated the feasibility of retrofitting a custom designed membrane system as a final separation process in a conventional water treatment plant (WTP). This paper presents preliminary findings from pilot tests conducted at a WTP located in Sheboygan, Wisconsin, which treats raw water with conventional processes. Settled water was treated, in lieu of granular media filtration, by an ultrafiltration (UF) pilot plant. To date, membrane applications for drinking water have involved proprietary membrane systems and designs, and generally have been limited to facilities with capacities on the order of 30 million gallons per day (mgd) or less due to high construction costs and scale-up issues. A custom approach to membrane system design described in this paper can offer significant advantages to utilities which: must comply with more stringent drinking water regulations; want to maximize the return on the investment in existing water treatment facility components (e.g., conventional pretreatment process units including granular filters and associated concrete structures); and/or have treatment capacities greater than 30 mgd and have not considered the use of membranes due to the high installed cost of the modular, proprietary system designs currently available. Two approaches to custom membrane system designs are discussed: a gravity-driven process where membranes may be implemented into the existing hydraulic gradeline of a water treatment plant; and, a pumped approach that is similar to existing proprietary systems, but offers the benefits of a custom design for maximizing the use of existing infrastructure and lower operating pressure. The pilot unit met the criteria for chemical cleaning frequency greater than 30 days and water quality performance when operated under head of 20 feet of water with settled water at a flux of 24 gfd and recovery of 90 percent. This result allows reuse of the filter boxes and filter capacity increase of at least 15 percent. This result also offers an economically viable membrane alternative. Includes 10 references, tables, figures.

Product Details

Edition: Vol. - No. Published: 01/01/2001 Number of Pages: 18File Size: 1 file , 480 KB