Many problems associated with acid mine drainage (AMD) are caused by the complex way molecular oxytgen (O_2) oxidizes reduced matter at surface temperatures. In aqueous solution, O_2 kinetically "prefers" to go through the formation of hydrogen peroxide (H_2O_2) as an intermediate. Being innately unstable, H_2O_2 is quickly decomposed back to water and oxygen in the presence of dissolved Fe and Mn, both catalysts for the decomposition. Direct addition of H_2O_2 to AMD produced similar results. Ozone (O_3) is a much faster and stronger oxidizer than either O_2 or H_2O_2. In the laboratory, O_3 rapidly precipitated Mn, F, Ni, Co, Pb, and Ag even in acidic solutions. The experiments indicate that AMD can probably be processed with ozone and metal oxides/hydroxide recovered in flow systems using only septic-tank-size reactors and small sedimentation ponds.
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