Recent development of active technologies for AMD treatment

Acid mine drainage (AMD) is the ingress water which come to the openings of the mine workings such as shafts and open pits. The decant water generally has a pH less than 7 (acidic). The acidity is caused by the oxidation of exposed metal sulphide ores, especially pyrite ore to sulphates and sulphuric acid in the presence of water and oxygen. However, in areas where the geology has a significant composition of basic ores, such as limestone and dolomite, the final AMD decanted from a mine can have a pH above 7 (alkaline AMD). The AMD treatment technologies are broadly classified into active and passive AMD treatment technologies. There are several sub-classes under each major class. Some of the treatment technologies have been used for several years, and they are generally referred to as conventional active or passive treatment technologies. The broad objective of this book chapter is to review recent disruptive active technologies for AMD treatment. These recent disruptive active AMD treatment technologies are mainly directed at either fast oxidation of Fe(II) and Mn(II) ions to Fe(III) and Mn(IV), chemical desalination, fast settling of sludges and possible generation of sealable products. The chapter will further advantages and limitations of these recent disruption active AMD treatment versus the conventional active treatment technologies. A global perspective on the recent development of disruptive AMD treatment technologies is discussed. Emphasis on case studies will be more biased toward the South African environment.