Effect of hydrous manganese dioxide on the treatment of low-turbidity source water: Plant-scale experience

The effect of potassium permanganate (KMnO(4)) preoxidation on the treatment of low-turbidity reservoir water was investigated through two years of operational data in a large-scale drinking water treatment plant (DWTP). KMnO4 facilitated the removal of pollutants [e.g., turbidity and chemical oxygen demand (COD(Mn))] by different units such as clarification, sand filtration, and granular activated carbon (GAC) adsorption. Although the addition of KMnO(4) increased the color and total Mn concentrations, the results of removal by clarification and filtration are promising. The average run length of anthracite filters decreased from 48 to 40.8 hours after the introduction of KMnO(4) and exhibited a negative correlation with KMnO(4) dosages (r(2) = 0.6912). The hydrous manganese dioxide in situ formed (delta MnO(2)) dominated in aiding coagulation and improving filtration to enhance pollutant removal in the KMnO(4) preoxidation process, and these effects were achieved at the expense of more frequent backwashing of anthracite filters. DOI: 10.1061/(ASCE) EE. 1943-7870.0000349. (C) 2011 American Society of Civil Engineers.