Biological treatment of acid mine drainage: An eco-sustainable strategy for removal of toxic pollutants

Abstract

• AMD consists of toxic pollutants such as heavy metals, sulfate, etc. • Improper discharge of AMD causes serious hazards to the ecosystems. • Biological technologies are green and sustainable for AMD treatment. • Bio-nanoparticles, SRB, MFCs, fungi, algae, or plants are used for AMD treatment. • Valuable products such as elemental sulfur, metals, and REEs are recovered from AMD. The indiscriminate discharge of acid mine drainage (AMD) from mine sites and other industrial operations has been a great concern, resulting in serious environmental and public health hazards. The waste stream consists of high concentrations of toxic organic and inorganic substances, warranting its treatment before disposal. Over the years, traditional physicochemical approaches, including membrane separation and ion exchange have been employed for AMD treatment. However, these techniques are unsatisfactory due to high operational costs, operational difficulties, and the release of secondary pollutants. Therefore, biological remediation strategies involving the application of microorganisms, plants, or plant-microbe interactions have increasingly gained attention as a green and sustainable solution for eliminating toxic pollutants present in the AMD. In addition, beneficial value-added products, including metals, rare earth elements, and elemental sulfur can be recovered from the acidic mine water, thus promoting wastewater management and reuse. The present review provides insights into the applicability of various biological technologies in the removal of toxic pollutants present in AMD. In addition, it discusses multiple beneficial valuable products that can be recovered from the acidic mine water, using biological approaches. Some constraints impeding commercial remediation of AMD as well as recommendations for future perspectives are also highlighted.