Impact of secondary disinfectants on copper corrosion under stagnation conditions

摘要

The objective of this paper was to assess the effects of secondary disinfectants on internal corrosion and water quality in copper piping under stagnant conditions. In particular, this study evaluated the effects of free chlorine, monochloramine, chlorine dioxide, and no disinfectant (as a control) on copper release under a range of corrosion inhibition conditions. Corrosion inhibition factors that were considered include pH and alkalinity. Each of the corrosion factors and each chemical disinfectant was varied at two levels (e.g., high and low concentration) to create a 2 3 factorial design for each chemical disinfectant. The water in the copper pipes was sampled and replaced after a 72 h stagnation period. Results show a decrease in copper release for all disinfectants used as compared to the control. In particular, the highest copper concentration measured was 2.55 mg/L, which corresponded to a pH of 7.2 and alkalinity of 100 mg/L and no chemical disinfectants. The lowest total copper concentration was 0.29 mg/L, which corresponded to the high pH and low alkalinity for the high dose of chlorine.