A bench-scale study was conducted to investigate whether chlorite would have a corrosive effect
on copper plumbing materials under simulated distribution system conditions. The study
evaluated the effect of chlorite on copper release at two chlorite concentrations, one high
concentration in disinfectant-free water, and one low concentration in chloraminated water. Any
potential impacts of copper release due to chloramine alone and nitrification in chloraminated
water were also investigated.
New copper pipe segments were tested in loops exposed to a recirculated flow consisting of
periods with flow and stagnation. Four water qualities were tested, including 5 mg/L chlorite in
disinfectant-free water, 0.8 mg/L chlorite in 1.5 mg/L chloraminated water, 1.5 mg/L
chloraminated water without chlorite, and 1.5 mg/L nitrified chloraminated water without
chlorite. Copper release from segments was monitored at the end of stagnant periods. The
results suggested chlorite at a dose of 5 mg/L had similar effect on copper release compared to
1.5 mg/L chloramine; chlorite at a dose of 0.8 mg/L to chloraminated water did not cause
additional copper release compared to chloraminated water.
Following the loop study, pitting and corrosion scale were assessed using an optical microscope
and scanning electron microscopy (SEM). Pitting products were analyzed using X-ray
diffraction. The results suggested chlorite tended to cause less pitting than chloramine alone and
tended to form a uniform scale on the pipes. Includes 19 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 3.3 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 43 |
| Published : | 11/01/2009 |
