Sources and behaviour ofmanganese during riverbank filtration

摘要

Based on global site examples, an overview of the sources and the behaviour of manganese during bank filtration is given. Atmany bank filtration sites, manganese concentrations between 0.4 and 1.6mg/l Mn are typical. The most common source of manganese during bank filtration is the microbial reduction of manganese(hydr)oxides and the subsequent mobilization of soluble manganese fractions from the riverbed and aquifer material. The quality of the infiltrating water and the aquifer composition control the microbial metabolism and thus, the manganese concentration of the bank filtrate. Precipitation of rhodochrosite (MnCO3) results in decreasing manganese concentrations at long flow paths and long residence times. Adsorption is relevant for the initial immobilization because manganese preferentially adsorbs onto existing manganese oxides and oxidizes faster due to the autocatalytic effects of oxides.