Biogeochemistry of acid mine drainage and a method to control acid formation

Abstract

A bacterium, Thiobacillus ferrooxidans, is of prime importance in the formation of acid drainage from pyritic material. Above pH 4.5, T. ferrooxidans increases initial acidification; below pH 4.5, it allows acidification to continue by oxidizing Fe/sup 2 +/. Below a pH of approximately 2.5, the activity of Fe/sup 3 +/ is significant and results in steady-state cycling between oxidation of pyrite by Fe/sup 3 +/ and bacterial oxidation of Fe/sup 2 +/. Laboratory and field tests demonstrate that inhibition of T. ferrooxidans by controlled release of anionic detergents can inexpensively reduce pyrite oxidation and acid formation.