Effects of major anions on iron release in drinking water supply system

摘要

Cast-iron is one of the most popular materials used in water distribution system in China. However, the iron release problem it brings up during decades has been a tough question to researchers. Iron release is a process that pipe corrosion scale breaks and release iron ions into bulk water deteriorating water quality and causing colored water problem. Literature shows that some factors such as pH, residual chlorine, DO and velocity of the bulk contribute to iron release. In this study, experiments are conducted to explore the effects of major anions in drinking water such as chloride, sulfate, and nitrate on iron release. The factors are examined separately and synthetically to observe detailed effects as separate factors and as complicated components. Higher concentrations of solutions result in higher iron release while lower concentrations have opposite results in single-factor experiments. Results suggest that the ORP level and conductivity of bulk water both have relations to the iron release.