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Hexavalent chromium reduction in a sulfur reducing packed-bed bioreactor.
Erkan Sahinkaya1, Adem Kilic, Muslum Altun
1Department of Bioengineering, Istanbul Medeniyet University, Göztepe, Istanbul, Turkey. erkansahinkaya@yahoo.com
Journal of Hazardous Materials
|April 24, 2012
Summary
Elemental sulfur bioreactors effectively remove toxic Cr(VI) from wastewater. Hydrogen sulfide produced biologically reduces and immobilizes chromium, enabling efficient wastewater decontamination.
Area of Science:
- Environmental microbiology
- Water treatment technologies
- Bioremediation
Background:
- Hexavalent chromium (Cr(VI)) poses significant environmental and health risks.
- Conventional Cr(VI) detoxification involves reduction to less toxic Cr(III).
- Biological methods offer sustainable alternatives for wastewater treatment.
Purpose of the Study:
- To investigate the efficacy of elemental sulfur as an electron acceptor for Cr(VI) reduction.
- To evaluate the performance of a packed-bed bioreactor using sulfur reduction.
- To assess chromium removal and immobilization in Cr(VI)-contaminated wastewater.
Main Methods:
- Operation of an elemental sulfur-reducing packed-bed bioreactor for over 250 days.
- Utilizing ethanol or acetate as carbon sources and electron donors.
- Monitoring Cr(VI) concentrations, COD oxidation, hydrogen sulfide production, and total chromium removal.
Main Results:
- Consistent Cr(VI) reduction and total chromium removal efficiencies exceeding 97% and 85%, respectively.
- Biologically produced hydrogen sulfide reached concentrations up to 750 mg/L.
- Cr(III) precipitation effectively immobilized reduced chromium within the bioreactor.
Conclusions:
- Elemental sulfur serves as an effective electron acceptor for generating hydrogen sulfide.
- This process efficiently reduces and immobilizes Cr(VI) in industrial wastewaters.
- Sulfur-based bioreactors provide a viable solution for Cr(VI) decontamination.
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