Biological arsenite oxidation with nitrate as sole electron acceptor

ABSTRACT

The potential of anoxic biological arsenite oxidation with nitrate as the sole electron acceptor was tested by using the acclimatized activated sludge which was chronically exposed under arsenite and nitrate coexisted aquatic environment. The activated sludge cultivated in a sequencing batch reactor was fed with arsenite and nitrate as the main substrates over six months. A series of batch experiments were conducted with acclimated sludge. Results showed that no obvious inhibition was observed in the anoxic arsenite oxidation linked to nitrate and nitrite reduction at the concentration of arsenite up to 35 mg As^III L⁻¹. Moreover, it was found that nitrite was accumulated over the reaction probably due to limited availability of arsenite. The kinetic study further suggested that the maximum specific arsenite oxidation rates (q_{obs, max}) with nitrate and nitrite as the electron acceptors were found to be 0.55 ± 0.10 mg As^III g⁻¹VSS min⁻¹ and 0.40 ± 0.04 mg As^III g⁻¹VSS min⁻¹, respectively.

KEYWORDS:

• Acclimatized sludge
• arsenite oxidation
• electron acceptor
• nitrate
• dynamic modeling

Acknowledgments

The authors thank the National Natural Science Foundation of China (No. 21107100), the International Cooperation Project of Zhengzhou City (No. 141PGJHZ535) and Outstanding Young Talent Research Fund of Zhengzhou University (No. 1421324067) for the financial support of this study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 21107100]; International Cooperation Project of Zhengzhou [grant number 141PGJHZ535]; Outstanding Young Talent Research Fund of Zhengzhou University [grant number 1421324067].