AWWA WQTC62459

Soft waters tend to reduce the life time of pipes from drinking water distribution systems and theinduced corrosion is likely to deteriorate water quality at the consumer's tap. New French legislation(decree 2001-1220 of 20/12/2001) effective since the end of 2003, recommends the supplied water notto be aggressive. Two types of treatments are commonly used to limit the corrosion effect of softwaters with low alkalinity: the addition of phosphate corrosion inhibitors; and, the neutralizationor remineralization of soft water. In order to provide guidelines for the network operator to choosesuitable treatment methods, a comparison must be made based on a technical (reliability and efficacy)and an economical standpoint (treatment cost and impact on pipes renewing). Within this study, a pilotexperiment has been performed to compare the impact of phosphate inhibitors with remineralizationon the degradation of pipes commonly used in drinking water distribution systems (cast iron, cementand steel) and household plumbing systems (copper). The impact of water treatments was studied onthe water (pH, metal leaching, etc) and on corrosion measurements (electrochemical probes, weightloss coupons). The results obtained over a 15-month period showed that the best water quality wasachieved with the remineralization approach. This water treatment strategy reduces metal pipecorrosion of soft water by 40% and improves both the copper and the iron release reduction by 50%. Includes 17 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

14

File Size:

1 file , 1.6 MB