Performance of single substrate in sulphate reducing bioreactor for the treatment of acid mine drainage

The focus of this study is to investigate efficiency of the sulphate reducing passive bioreactors for the treatment of acid mine drainage. The performance of locally available substrates (manures, woodchips, millet fodders and sugarcane waste) were examined for the treatment of acid mine drainage. The manures showed efficient removal of metals and other pollutants. With cow manure, buffalo manure and goat manure pH increased from initial 2.70 to 6.25, 7.10 and 7.50. All cellulosic wastes also raised pH in a range of 4.83–5.32. Significant reduction was observed in Eh, acidity and sulphate concentration also. It was observed that: 51.49–99.32% of Fe, 84.95–99.97% of Cu, 35.11–99.78% of Zn, 17.87–99.14% of Ni, 63.55–99.02% of Co and 12.68–73.86% of Mn were removed in maximum retention period of 10 days. Thus manures can be cost effective as a single substrate in a passive treatment method for removal of metals from AMD in bioreactors. Also chemical makeup of substrate provided an insight on the ability of sulphate reduction and metal removal.

► SRBR received much attention as promising biotechnology for the treatment of AMD.
► Performance of 10 organic substrates was examined for the treatment of AMD.
► Manures show good performance with respect to SO4, acidity and metal removal.
► Chemical characterization is an important criteria for substrate selection.
► Metal precipitation is easier as sulphide compared to hydroxide due to lower solubility.