Application of Bacterially Produced Hydrogen Sulphide for Selective Precipitation of Heavy Metals

Abstract

The generation of acid mine drainage (AMD) and its discharge into the environment surrounding abandoned mines is likely to cause serious environmental pollution. Numerous techniques are available for neutralization and removal of metals and sulphates from AMD. One of the best available technologies for the removal of metals from AMD is the application of the sulphate-reducing bacteria (SRB). This process is based on the production of biogenic hydrogen sulphide by SRB, which consequently reacts with metal ions in the water forming sparingly soluble metal sulphides. The main objective of this work was to study the process of the heavy metals precipitation from AMD by bacterially produced hydrogen sulphide combined with intermediate steps of metals precipitation by sodium hydroxide at various pH values. The experiments were conducted with AMD coming from the abandoned and flooded deposit of Smolnik (Slovak Republic). This process is able to sequentially precipitate Cu(2+), Zn(2+) and Fe(3+) in the form of sulphides, Al(3+), Fe(2+) and Mn(2+) in the form of hydroxides.