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The Cities of Albany and Millersburg, Oregon operate a Joint Water TreatmentPlant which went on-line in November 2005, using immersed membranes to treatwater from the Santiam River at a capacity of 16.5 mgd. The City of Albanyoperates a conventional plant treating water from a canal diversion off the samesource. The first round of quarterly disinfection byproduct (DBP) samplingconducted after the new plant went on-line showed elevated levels of haloaceticacids. In response to the DBP results, the Cities evaluated the use of in-lineaddition (no flocculation or settling provided) of a nominal dose (5 mg/L) ofaluminum chlorohydrate (ACH) as a means of reducing DBP precursors ahead ofthe free chlorine disinfection process employed at the new plant. Full-scaletesting of ACH addition was combined with bench-scale simulated distributionsystem (SDS) DBP testing of plant finished water to document the reduction ofDBPs through the ACH addition. Testing confirmed that a 5 mg/L dose of ACHcould significantly reduce HAA concentration under SDS conditions, and thatmonitoring raw water turbidity and chlorine demand through the plant areexcellent indicators of when the coagulant dose needs to be adjusted due tochanges in source water quality. Coagulant testing was performed in conjunctionwith performance testing of the membrane filtration system, whereby one cell ofthe system was operated for several 30-day test periods under controlledconditions to simulate future plant capacity requirements. The membranesystem performance testing showed minimal impact on membrane fouling ratesdue to the ACH addition. Includes tables, figures.

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Edition: Vol. - No. Published: 03/01/2007 Number of Pages: 19File Size: 1 file , 3.1 MB