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A bench-scale study was conducted to investigate whether chlorite would have a corrosive effecton copper plumbing materials under simulated distribution system conditions. The studyevaluated the effect of chlorite on copper release at two chlorite concentrations, one highconcentration in disinfectant-free water, and one low concentration in chloraminated water. Anypotential impacts of copper release due to chloramine alone and nitrification in chloraminatedwater were also investigated.New copper pipe segments were tested in loops exposed to a recirculated flow consisting ofperiods with flow and stagnation. Four water qualities were tested, including 5 mg/L chlorite indisinfectant-free water, 0.8 mg/L chlorite in 1.5 mg/L chloraminated water, 1.5 mg/Lchloraminated water without chlorite, and 1.5 mg/L nitrified chloraminated water withoutchlorite. Copper release from segments was monitored at the end of stagnant periods. Theresults suggested chlorite at a dose of 5 mg/L had similar effect on copper release compared to1.5 mg/L chloramine; chlorite at a dose of 0.8 mg/L to chloraminated water did not causeadditional copper release compared to chloraminated water.Following the loop study, pitting and corrosion scale were assessed using an optical microscopeand scanning electron microscopy (SEM). Pitting products were analyzed using X-raydiffraction. The results suggested chlorite tended to cause less pitting than chloramine alone andtended to form a uniform scale on the pipes. Includes 19 references, tables, figures.

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Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 43File Size: 1 file , 3.3 MB