MICROBIOLOGICAL STUDY OF ACID MINE WATERS:

Waters issuing from bituminous mines may be either acid or alkaline. The acid mine waters are objectionable; their disposal or abatement is highly desirable. Many agencies are concerned in the reduction of this important industrial waste for several reasons: pollution with acid wastes renders streams extremely acidic, pH 2.0 to pH 4.0, which results in the annihilation of the majority of commonly encountered micro- and macroorganisms in water; high concentrations of ferric, ferrous, and sulfate compounds are hazardous to children using such streams as bathing areas; the aesthetic quality of these streams is in a deplorable condition due to the deposition of ferric hydroxide in the channels of the streams. FORMATION OF ACID MINE WATER The oxidation of sulfur and sulfur-bearing compounds in coal seams results in the formation of large quantities of acid compounds available for solution in water. It is assumed that ferric disulflde is oxidized to soluble ferrous sulfate and sulfuric acid: 2FeS2 + 702 + 2H2O> 2FeSO4. (1) When these acid wastes enter streams they are exposed to atmospheric conditions and atmospheric oxidation of ferrous sulfate to ferric sulfate and water occurs: 4FeSO4 + 2H2SO4 + O2> 2Fe2(SO4)_3 + 2H2O. (2) The subsequent hydrolysis of ferric sulfate yields ferric hydroxide