Microbial treatment of acid mine drainage (AMD): A review

The oxidation of sulfide minerals, present in many current and historical abandoned mining activities of polymetallic deposits with sulphide, especially pyrite or others as pyrrhotite or chalcopyrite, generates acid mine drainage rich in potentially toxic elements that can contaminate sensitive water bodies, either superficial or dep. Pyrite oxidation and to a lesser extent, that of other sulfides, upon exposure of air and water, is conducted via two mechanisms: one of inorganic nature, due to the molecular oxygen or the ferric ion; and another mechanism with biotic intervention, mainly sulphur or iron-oxidizing bacteria. The need to mitigate and prevent AMD formation, has promoted the development of numerous studies on the oxidation mechanisms and AMD prevention. The research findings have been the basis for the development of prevention or control technologies based on physical, chemical and biological processes, the latter being much less harmful to the environment, given that they are already present there and it does not entail the addition of artificial agents. The aim of this review is to examine documentation focused on techniques that inhibit the action of the iron-oxidizing bacteria (prevention techniques) and the use of microbial communities to reduce the acidity of existing AMD (remediation techniques).