Combination of Chemical and Biological-Chemical Methods for Elimination of Metals from Acid Mine Drainage

Abstract

Each acid mine drainage has a specific composition, but always contains sulphuric acid, dissolved heavy metals, sulphates, iron precipitates and their pH can be very low. The elimination of metals form the acid mine drainage is a severe environmental problem andhas been a long-standing major concern to scientists, engineers, industry and governments. Various methods are used for the metalsremoval from waters, but any of them have been applied under commercial-scale conditions. Mostly studied are chemical and biological-chemical methods. Main aim of the paper was to interpret the combination of chemical and biological-chemical methods for theheavy metals elimination from the synthetic solution of acid mine drainage, coming from the zinc mine located in Tùnel Kingsmilloutlet of the Rio Yaulì (district of Yauli – Perù). The metals selective precipitation as hydroxides (chemical method) and sulphides(biological-chemical method) at the various values of pH acid mine drainage is the fundamental of the examined process. For thehydrogen sulphide production the sulphate-reducing bacteria of genus Desulfovibrio was used. The selective sequential precipitationprocess reaches the selective precipitation of chosen metals with 97–99% efficiency – Fe, As, Al and Mn in the form of metal hydroxides,Cu and Zn as metal sulphides