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Blanck, C. A., D. F. Mead and D. J. Adams, 1996. Effective Control of Zebra Mussels Using a High Molecular Weight Polymer, American Water Works Service Company, Ohio-American Water Company Abstract from The Sixth International Zebra Mussel and Other Aquatic Nuisance Species Conference, Dearborn, Michigan, March 1996 Effective Control of Zebra Mussels Using a High Molecular Weight PolymerThe application of 1.5 mg/l to 2.0 mg/l of high molecular weight polymer (Dimethyl-Diallyl-ammonium chloride, DMDAAC) has been shown to be effective in killing Zebra Mussels in the 24 inch and 30 inch intake lines at the Ohio-American Water Company Ashtabula District water treatment plant. This was proven in a plant trial in 1990 and again after the installation of permanent polymer feedlines in the summer of 1992. The paper also discusses the cleaning of the two intakes which was needed prior to installation of permanent polymer feed lines. During the interim period between the plant trial and the installation of the permanent feed lines in 1992 no polymer had been fed. This necessitated the "pigging" of the two intakes to remove several blockages caused by driftwood, sand, and other debris which had accumulated over several decades and to remove Zebra Mussels that had accumulated since 1990. The introduction of Zebra Mussels into the Great Lakes in 1988 threatens water intakes and water treatment plants. The ability of the mussel to attach to hard surfaces and each other reduces the flow rates of intakes. Water utilities and other industries use several chemical methods to control the infestations of the mussels into intake pipes. These methods include the use of chlorine and potassium permanganate. The use of the cationic polymer to kill the Zebra Mussels in the intake does not result in an increase in Total Trihalomethanes which is a concern when using chlorine for mussel control. Additionally, the polymer does not require vigilant monitoring as is needed to prevent "pink" water in the distribution system when potassium permanganate is applied for Zebra Mussel control. The cationic polymer (Calgon Catfloc LS) was proven to be effective in killing the Zebra Mussels but also (1) reduced the alum usage by as much as 70-80%; (2) reduced the amount of treatment residuals to the lagoon; (3) reduced the soluble aluminum in the plant effluent; and (4) improved the Stability Index. Key Words: Zebra_mussel, Chemical_control, Industry |