Development of a novel packed-bed bioreactor to remove sulfate from taconite process water

摘要

Column experiments were conducted to evaluate sulfate reduction from taconite mining process water using various organic and inorganic substrates. The best removal occurred in columns fed an external organic carbon source. Based on the column results, a demonstration-scale treatment system was constructed using an inorganic iron-rich media to promote iron sulfide precipitation. Using ethanol as the carbon source, sulfate reduction averaged 50% from startup in July 2003, through September 2003, at a process water feed rate of 400 L/minute and an average influent sulfate concentration of 850 mg/L. The carbon source for the system was then switched to a blend of ethanol and molasses and operation continued through January 2004. Sulfate treatment remained consistent and was unaffected by severe winter temperatures. Limited fouling of the treatment media was observed over the 7 months of testing. Treatment testing was discontinued in February but resumed in June 2004, with additional results pending.