AWWA WQTC62586

Water District No. 1 of Johnson County, Kansas (WaterOne), is a large utility thatsupplies water to approximately 340,000 people in the Kansas City metropolitan area.WaterOne has two facilities (55 and 125 mgd) that treat water from the Missouri andKansas Rivers by presedimentation, preoxidation and disinfection with chlorine dioxide,two-stage lime softening, dual media filtration, and disinfection with chlorine. Currently,WaterOne is planning a new 30 mgd treatment facility that will treat Missouri Riverwater withdrawn through horizontal collector wells. One proposed treatment processwould include lime softening and filtration by microfiltration/ultrafiltration (MF/UF) membranes. WaterOne and Black& Veatch performed a 6 month pilot study to evaluate the potential effects of lime-softenedwater, specifically water with pH of 9.5 and calcium carbonate precipitationpotential greater than 20 mg/L as CaCO₃, on the MF/UF membranes.The membrane system suppliers were allowed to specify the flux and other operatingsetpoints, but were required to meet water recovery, membrane cleaning, and specificflux recovery following CIP values outlined in the pilot testing protocol. The pilottesting extended over several seasons, so the impact of water temperature, total organic carbon (TOC) increaseswith spring runoff, and process changes upstream of the membrane systems wereinvestigated. An on-line alkalinity, total hardness, and TOC analyzer were also used todetermine the effects of calcium carbonate precipitation potential and TOC on themembrane fouling rate.This paper discusses the results of the pilot study and fouling rates as a function of TOCconcentration, upstream treatment with polymer, and calcium carbonate precipitationpotential. The paper also provides practical guidance for other softening plants that areconsidering MF/UF membranes. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

16

File Size:

1 file , 10 MB