Full Description

While previous studies have extensively focused on treating water in order to prevent corrosion, thefactors that affect stability of corrosion scales and the role they play on the quality of drinking waterwithin distribution systems have not been considered relevant until now. This investigation assessedthe response of corrosion scales from aged galvanized water distribution systems under alternativewater sources - groundwater and a blend of ground and surface water. A pilot project using pipesfrom various distribution systems has been designed and monitored for variations in water quality.The system is designed to simulate the actual operating conditions of a distribution system with 2,20 and 40 years of service. Continuous monitoring of water quality has been recorded over thecourse of 18 months. Results showed that under similar water characteristics each pipe respondeddifferently, suggesting that both the structure and composition of scale play an important role inmaintaining the quality of water within the distribution system. The introduction of a new watersource (the surface and groundwater blend) produced general reductions in iron release, turbidityand color values. The influent water quality parameters that showed significant variations comparedto the base-line were dissolved oxygen, pH, alkalinity, and sulfates. In general, older pipes, whichhave much more developed oxide scales, were more sensitive to water quality variations than thenew pipe. Overall, the main factors affecting water quality within the pipes were identified asincrease in temperature, increase in dissolved oxygen, increase in pH, decrease in alkalinity, andincrease in sulfates. Includes 8 references, tables, figures.

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Edition: Vol. - No. Published: 06/17/2004 Number of Pages: 14File Size: 1 file , 320 KB