Effect of organic substrate thickness on synthetic acid mine drainage (AMD) treatment

Abstract

A Successive Alkalinity Producing System (SAPS) employing an organic substrate of peat soil and limestone aggregate was investigated for the restoration of synthetic Acid Mine Drainage (AMD). The composition, carbon content, and particle size distribution of the peat soil and limestone were determined by characterisation. Iron sulphate (FeSO4) and sulfuric acid were used to create synthetic AMD (H2SO4). The synthetic AMD was acidic (pH4.0) and had a concentration of iron (Fe) of 100 ppm. A laboratory scale physical model of a tailing pond was created. The synthetic AMD was introduced and filtered through the media. Following that, samples of effluent water were collected and examined to ascertain the pH level. Furthermore, the Fe concentration was determined using a UV-Vis test with a retention duration ranging from 6 to 48 hours. After only 6 hours of retention time, the new technology successfully reduced more than 85% iron concentration and neutralised pH. These findings demonstrated that a combination of peat soil and limestone of adequate thickness might potentially be recommended as an additional treatment media for treating AMD with SAPS.