AWWA WQTC65707

Compliance with new Safe Drinking Water Act (SDWA) regulations has resulted in a change in finished waterquality for many systems throughout the United States. Most often the finished waterquality change has been due to compliance with disinfection byproduct regulations (Stage1 D/DBP Rule). Changes in finished water quality has been concurrent with an increase in leadoccurrence in some distribution systems, and issues with coloredwater (iron), or problems with new building plumbing systems. Theincrease in corrosion is not immediately known because changes in water quality do notillicit an immediate corrosion byproduct response and routine monitoring parameters donot indicate a problem exists. In addition, since many systems have been on reducedmonitoring under the Lead and Copper Rule, specific analysis for compliance parametersof lead and copper are not routinely done, with as much as six years allowed betweensampling for Pb or Cu for those on reduced monitoring. Many factors can increase corrosion rates, making it difficult to determine the exactcause. In addition using corrosion inhibitors is only effective if the type and dose isproperly selected. Problems with lead in recent years have been attributed to change intreatment processes in order to lower disinfection byproducts. Lower organics, higherchlorides, higher sulfates, higher pH's, chloramines and "free ammonia", and loweralkalinity may all be playing a role.Finding a solution to drinking water corrosion problems requires a careful review offinished water characteristics, distribution system materials, types and locations ofcomplaints, and a review of water quality changes throughout the entire distributionsystem including: residual disinfectant levels, inhibitor phosphate concentrations, pH,alkalinity, and nitrate/nitrite (in chloramine systems). Includes 5 references, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2007

Number of Pages:

10

File Size:

1 file , 260 KB