AWWA JAW34106

Previous investigations have shown ferrous iron application to be an effective and economically feasible method of removing residual chlorine dioxide and chlorite ion from drinking water. This treatment, however, was not effective in reducing concentrations of chlorate ion. To address this issue, combined methodologies (alternative chlorine dioxide generation and application together with iron reduction) have been developed that significantly reduce finished-water oxychlorine residuals. These methodologies and the effect of various treatment conditions toward low-level chlorate ion formation are the focus of this article. Includes 31 references, tables, figures.