Source water and microfiltration plant manganese control study

摘要

A combined field and laboratory manganese study was conducted to evaluate manganese sources and explore treatment options. Through source water characterization, it was found that biochemical processes in the river affected manganese concentrations more than any processes in the lake feeding the river. Because measures taken in the lake would not control manganese at the plant intake, in-plant treatment was required. Bench-top experiments evaluated three treatment trains: potassium permanganate (KMnO4) direct oxidation followed by microfiltration (MF), manganese-coated media bed before MF, and manganese-coated media bed after MF. All processes removed manganese, with the media bed processes consistently achieving ＜ 0.004 mg/L and KMnO_4 oxidation reaching as low as 0.008 mg/L Mn. Organic carbon and trihalomethane formation potential removals were comparable, but the media bed after MF exhibited the highest rate of membrane fouling. This study provides a holistic understanding of manganese source and treatability, which should prove useful to other utilities with similar manganese issues.