Rotating-disc biological treatment of acid mine drainage

Abstract

The rotating biological contactor (RBC) was investigated for application to treatment of acid mine drainage, specifically, oxidation of Fe/sup 2 +/ to less soluble Fe/sup 3 +/. At three coal mining locations in Pennsylvania and West Virginia, treatment of six heterogeneous mine waters was studied in experiments with pilot-scale (0.5-m diameter) and prototype (2.0-m) RBC units. Specific characteristics examined in detail for their effect on biological treatment were temperature, pH, and influent Fe/sup 2 +/ concentration. Continuous biological oxidation of Fe/sup 2 +/ was accomplished at natural mine water temperatures as low as 0.4/sup 0/C (Hawk Run, Pa.) and as high at 29/sup 0/C (Crown, W.Va.). Performance of the RBC was unaffected at influent mine water pH valves in the range of 2.18 to 5.50 (Crown, W.Va.). Lower influent Fe/sup 2 +/ concentrations in Hollywood, Pa. mine drainage (71.6 mg/l) resulted in higher oxidation efficiency as compared to treatment efficiency when mine water contained approximately twice the influent Fe/sup 2 +/ content.