Influence of Carbon Source on Biological Nitrogen Removal by Immobilised Bacteria

Wilawan Khanitchaidecha, Tatsuo Sumino, Futaba Kazama

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DOI: 10.4236/jwarp.2010.26059                

Abstract

Acetate, ethanol, and hydrolysed rice were used as external carbon sources in an ammonium removal process employing immobilised bacteria. The influence of the carbon source on the occurrence of free cells and total nitrogen removal efficiency was examined at C/N ratios of 1.5 (low), 2.5 (medium), and 3.5 (high). At the low C/N ratio, no free cells were found in the reactors and the use of acetate as the carbon source resulted in the highest total nitrogen removal efficiency, followed by ethanol and hydrolysed rice. The occurrence of free cells in reactors fed with acetate and ethanol led to a negligible increase in the total nitrogen removal efficiency with increasing C/N ratio. The results suggest that acetate is the most appropriate carbon source for nitrogen removal and that the number of free cells should be minimized to achieve the highest efficiency during long-term operation.

Keywords

Nitrogen Removal, Nitrification and Denitrification, Carbon Sources

Conflicts of Interest

The authors declare no conflicts of interest.

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