Full Description

More utilities are using chloramines in place of free chlorine because of their greater stability forbetter compliance with both the Total Coliform Rule and more stringent requirements of theDisinfectants/Disinfection Byproducts Rule. New information about disinfectant-induced changes inoxidation reduction potential (ORP), lead chemistry, scale formation and interactions with naturalorganic matter have contributed to a greater understanding of the factors influencing increasedcorrosion and metals release associated with a change in disinfectant. As such, AwwaRF funded thisproject (#3107) to build upon the water industry's limited understanding of this effect. This projectincludes laboratory studies and a field sampling program. Identical pipe-loop setups and componentstesting procedures are being conducted at the HDR Applied Research and Technology Center(ARTC) in Bellevue, Washington and the District of Columbia Water and Sewer Authority (DCWASA)testing facility in Washington, DC. This paper provides a brief description of the setups, operations,preliminary data, and discussion of preliminary results. In general, preliminary results indicate thepresence of chlorine tends to suppress lead release from old lead pipe but this effect appears to beless prominent for newly exposed lead-bearing materials. At the same time, copper release appears tobe accelerated in the presence of chlorine. Both these effects are affected by water qualityparameters, scales present on the surface and overall exposure history of corroding surfaces. Resultsfrom this study will be of interest to utilities that are considering converting from free chlorine tochloramines, and/or utilities concerned with maintaining simultaneous compliance with the Lead andCopper Rule and the Stage 2 D/DBPR. Includes 24 references, tables, figures.

Product Details

Edition: Vol. - No. Published: 11/01/2007 Number of Pages: 20File Size: 1 file , 1 MB