Manganese coprecipitation/adsorption behaviour and sludge volume ratios in chemical treatment systems for mine drainage: a review of the literature and a pilot‐scale experiment

Manganese removal at lower pH and sludge volume in settling ponds are some of the major issues affecting chemical treatment systems for mine drainage. First, Fe and Al existing in mine drainage coprecipitate with and/or adsorb Mn. Eight chemical treatment facilities were reviewed from literature and a pilot-scale experiment was also conducted in the Daedeok mine in South Korea. The Mn/(Fe + Al) ratio revealed a positive linear relationship with the lowest pH at discharge, and regression lines were generated. This relationship may be used to predict the pH required to remove Mn considering coprecipitation/adsorption. Second, the ratios of the generation rate of sludge to the required settling volume at five semi-active treatment facilities were evaluated from literature. This ratio is referred to as the sludge-settling volume ratio, which can be used as one of the factors in deciding between semi-active and active treatment systems.