AWWA ACE63234

Bench-scale studies were performed to evaluate several strategies to avoid post-filter iron/manganese precipitation. The relative performance of three alternative oxidants was evaluated - chlorine, potassium permanganate and chlorine dioxide with respect to iron and manganese removal. For each oxidant, the kinetics and optimal oxidant dose necessary to achieve compliance with the Secondary Maximum Contaminant Level (SMCL) for both iron and manganese were investigated. (The SMCL for iron is 0.3 milligrams per liter (mg/L), while that for manganese is 0.05 mg/L.) Effect of these oxidants on other water quality parameters such as turbidity, UV254 and Total Organic Carbon (TOC) reduction and formation of Trihalomethanes (THMs) were also studied. It is expected that the findings of this study will be useful to City in resolving iron/manganese issue in their raw waters, once the deep bed granular activated carbon (GAC) filters have been implemented. Includes tables, figures.