Low temperature removal of inorganic sulfur compounds from mining process waters
Article first published online: 28 JAN 2011
Copyright © 2011 Wiley Periodicals, Inc.
Biotechnology and Bioengineering
Volume 108, Issue 6, pages 1251–1259, June 2011
How to Cite
Liljeqvist, M., Sundkvist, J.-E., Saleh, A. and Dopson, M. (2011), Low temperature removal of inorganic sulfur compounds from mining process waters. Biotechnol. Bioeng., 108: 1251–1259. doi: 10.1002/bit.23057
- Issue published online: 12 APR 2011
- Article first published online: 28 JAN 2011
- Accepted manuscript online: 18 JAN 2011 12:00AM EST
- Manuscript Accepted: 3 JAN 2011
- Manuscript Revised: 22 DEC 2010
- Manuscript Received: 6 OCT 2010
- Acidithiobacillus ferrivorans;
- continuous process
Process water and effluents from mining operations treating sulfide rich ores often contain considerable concentrations of metastable inorganic sulfur compounds such as thiosulfate and tetrathionate. These species may cause environmental problems if released to downstream recipients due to oxidation to sulfuric acid catalyzed by acidophilic microorganisms. Molecular phylogenic analysis of the tailings pond and recipient streams identified psychrotolerant and mesophilic inorganic sulfur compound oxidizing microorganisms. This suggested year round thiosalt oxidation occurs. Mining process waters may also contain inhibiting substances such as thiocyanate from cyanidation plants. However, toxicity experiments suggested their expected concentrations would not inhibit thiosalt oxidation by Acidithiobacillus ferrivorans SS3. A mixed culture from a permanently cold (4–6°C) low pH environment was tested for thiosalt removal in a reactor design including a biogenerator and a main reactor containing a biofilm carrier. The biogenerator and main reactors were successively reduced in temperature to 5–6°C when 43.8% of the chemical oxidation demand was removed. However, it was found that the oxidation of thiosulfate was not fully completed to sulfate since low residual concentrations of tetrathionate and trithionate were found in the discharge. This study has demonstrated the potential of using biotechnological solutions to remove inorganic sulfur compounds at 6°C and thus, reduce the impact of mining on the environment. Biotechnol. Bioeng. 2011; 108:1251–1259. © 2011 Wiley Periodicals, Inc.