Environmental Impacts and Technologies for Remediation of Acid Mine Drainage: Current Situation and Perspectives

Abstract

Mining and mineral processing produces large volumes of waste rock and mill tailings, which correspond to the main sources of acid mine drainage (AMD) generated through the oxidation of sulfide minerals. This acid effluent is characterized by high concentrations of sulfate, iron, aluminum, and trace elements, such as arsenic and manganese, representing a recalcitrant environmental problem around the world. For example, the AMD might flow into groundwater, streams, and rivers, giving rise to several environmental problems of high concern. Besides the parental rock material, seasonal variations can significantly affect the acid production and behavior along the environmental systems. Therefore, AMD requires a careful environmental and geochemical evaluation so that the most properly technology for the removal of pollutants can be applied. The main remediation systems for the removal of contaminants from AMD can be divided among preventive, passive, and active techniques. Treatment processes have been projected so that treated effluents and solid waste can be properly recycled and reused for industrial applications. Emerging technologies based on nanomaterial and environmental-friendly material are showing improved performance to remove complex analytes from AMD, allowing the recovery of metals as a potential alternative for sustainable mining. In this chapter, the main factors controlling the AMD generation and their environmental impacts are discussed, in addition to the various technologies applied for the remediation and removal of toxic metals from acidic drainages, highlighting the development of greener material for freshwater sustainability.