The Removal of Nickel from Mine Waters Using Bacterial Sulfate Reduction.
Proc 1991 Natl Mtg Soc of Surface Mng & Reclam 1991 1:97-107
The U.S. Bureau of Mines conducted experiments to determine if a mushroom-compost-based sulfate reduction system could be used to treat nickel-contaminated mine waters. Sulfate reduction systems were established in columns containing acid-washed mushroom compost. Simulated mine waters containing 2,000 mg/l sulfate and 50 to 1,000 mg/l nickel were adjusted to ph 4.5 and pumped through the columns at flow rates between 15 and 25 ml/hr. During the first 9 days of operation, virtually all influent nickel was removed in the columns by sorption and ion exchange mechanisms. The nickel removal rate then dropped to 18 to 30 mg ni/day (7.8 to 12.8 Nmol/g- substrate/day), probably owing to low sulfate reduction rates. When sodium lactate was added to the inflow, a sustained and sevenfold increase in the nickel removal rate was observed. Bacterial sulfate reduction rates measured in mushroom-compost-based wetlands exposed to coal mine drainage are 2 to 20 times faster than the rates observed in this study. Low sulfate reduction rates in the columns may have been due to the inhibition of microbial activity by high nickel concentrations and the removal of labile organic compounds from the mushroom compost substrate during acid washing. Results of this study indicate that bacterial sulfate reduction can effectively treat nickel concentrations up to 500 mg/l if labile carbon is nonlimiting.
Proc. 1991 Natl Mtg Soc of Surface Mng & Reclam.; V. 1, Am Soc Surface Min & Reclam, Pp 97-107