ACID MINE DRAINAGE TREATMENT AND METAL REMOVAL BASED ON A BIOLOGICAL SULFATE-REDUCING PROCESS

ABSTRACT The key purpose of this research was to explore the capacity of an anaerobic stirred batch reactor (ASBR) to deal with acid mine drainage (AMD) based on the activity of sulfate reducing bacteria (SRB). The tests showed that SRB produced hydrogen sulfide that precipitated the metals Fe2+, Zn2+, and Cu2+. Ethanol was used as both the only source of carbon and electron donor. Throughout the experiment, the ratio of chemical oxygen demand (COD) to sulfate was constant at 1.0. The reactor was operated for 218 days using synthetic AMD at pH 4.0 containing 1000 and 1500 mg·L-1of sulfate,100 mg·L-1of Fe2+, 20 mg·L-1Zn2+, and 5 mg·L-1Cu2+. The metal removal rates were greater than 99% with effluent pH of 6.5 to 7.4. The sulfide concentration reached 56.6 mg·L-1 and sulfate removal was 43 to 65%.