Active Physical Remediation of Acid Mine Drainage: Technologies Review and Perspectives

The successful acid mine drainage (AMD) treatment needs site-specific installation and implementation, as well as the deployment of technology that is compatible with the pollutants contained in the AMD. If key by-products of the AMD can be recovered, the financial sustainability of the AMD remediation method may be greatly improved. Additional research into novel and innovative solutions is necessary to advance in this direction. To accomplish this, it is necessary to have a complete awareness of current remediation technologies that are available and accessible. Active physical treatment methods such as ion exchange, adsorption, electrochemistry, and membrane techniques were examined in this article. Membrane technology excels in terms of ease of use, versatility, and environmental effect but produces brine streams the management of which remains vital for future adoption of the technology. Liquid membranes (LM), Micellar Enhanced Ultra-Filtration (MEUF), and Polyelectrolyte Enhanced Ultra-Filtration (PEUF) are all innovative membrane technologies that may provide some possibilities for metal recovery from chemical sludge and/or brine streams. Electrochemical technologies are considered an attractive alternative for AMD treatment, because they require only electricity as a consumable and can treat AMD to high standards by removing metals via (co)precipitation and sulfate via ionic migration (when an anion-exchange membrane is used in the configuration), while producing significantly less sludge. However, the accepted shortcomings include membrane/electrode fouling produced by (co)precipitates on the active surfaces necessary for the process, a lack of understanding regarding the effective scaling up to industrial scale, and the relatively expensive capital expenditure (CAPEX) required. The removal of heavy metals from AMD effluents by adsorption has a number of technical and environmental benefits, including high efficiency, and environmental friendliness. Despite its benefits, this technique has certain hurdles, such as the production process for low-cost adsorbents.