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Treating highly turbid waters with minimal pretreatment and the effect of polymer use on themembrane performance was investigated for this study. Typically, use of polymer upstream ofmembranes is not practiced since it may irreversibly foul the membrane; however, use ofpolymer could improve the performance of pretreatment processes, thereby improving theefficiency of the membranes. This paper discusses the effect of a cationic polymer up to doses of150 mg/L and turbidity in excess of 100 NTU on a membrane system.WaterOne of Johnson County, Kansas, treats Missouri River water at a remote facility before itreceives further treatment at the Hansen WTP. Treatment at the Missouri River facilitiesincludes sedimentation with aluminum sulfate and a cationic polymer to reduce the turbidity ofthe raw water from as high as several thousand NTU to between 10 and 20 NTU. A pilot studywas conducted to evaluate the performance of submerged ultrafiltration (UF) membranes on thesettled Missouri River water. The treatment unit was set at a flux of 28 gfd and a recovery of 92percent. During part of the study period, the recovery was increased to 96 percent in an attemptto quantify the effect of increased solids concentration on membrane permeability. The rawwater turbidity was as high as 4,000 NTU during two separate occasions and the settled waterturbidity exceeded 100 NTU.Polymer dosages as high as 10 mg/L applied at the pretreatment facility did not appear toadversely affect the membrane performance. Two additional polymer tests were conductedusing incremental polymer doses up to 150 mg/L immediately upstream from the treatment unit.Following the polymer tests, the membranes were cleaned by CIP procedures to evaluate their recovery capability. Includes tables, figures.

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Edition: Vol. - No. Published: 03/01/2005 Number of Pages: 8File Size: 1 file , 380 KB