Study of microbial contribution in alkalinity generation during treatment of acid mine drainage by laboratory successive alkalinity producing system

Abstract

Presently, the acid mine drainage (AMD) is a very common environmental problem being faced by mining communities throughout the world. The AMD generated in the mines is characterized by low pH value which results in further dissolution of minerals and release of toxic metals into the water. The successive alkalinity producing system (SAPS) is a passive treatment system which has evolved to harness the treatment benefits of limestone and wetlands together. In this laboratory study four identically designed SAPS were operated simultaneously with four different types of synthetic AMD for different Hydraulic Retention Time (HRT). The cow compost, sawdust and limestone were used in SAPS. The % contribution of organic substrate in net alkalinity generation due to microbial activities was measured for different HRTs. In this study is observed that organic substrate has contributed 70.96% and limestone layer contributed 29.04% in net alkalinity generation by SAPS.