Anaerobic reactors for the treatment of sulphate and metal-rich wastewater: a review

Acid mine drainage (AMD) causes serious environmental issues once present in the food chain directly affects human health due to its high acidity, the presence of heavy metals and sulphate compounds. For this reason, the constant search for new technologies for the treatment of AMD is becoming increasingly necessary. This review aims to highlight the characteristics and damage caused by AMD and the main treatment approaches. With special emphasis on anaerobic bioreactors containing sulphate-reducing bacteria (SRB) as a sustainable and economical alternative for the treatment of this type of effluent, due to the ability of microorganisms to use toxic metals in their metabolism, besides generating alkalinity in the environment and neutralising acidic compounds. SRB metabolise the electron donor and the sulphate ion, generating hydrogen sulphide and carbonic acid. In this way, future perspectives and major advances involving the treatment of this wastewater through microorganisms were addressed.