International Journal of Environmental Science and Development

Abstract—This study reports the effect of denitrifying phosphorus accumulating organisms (DPAOs) at low DO on simultaneous nitritation-denitritation and enhanced biological phosphorus removal process. DPAOs were enriched in a sequencing batch reactor (SBR) under anaerobic-anoxic-aerobic condition with an active DPAO population of about 30%. The nitrite-oxidizing bacteria (NOB) washout from the nitrifying sludge was obtained in a separate SBR operated under anoxic-aerobic conditions. At a 1:1 ratio of nitrifying to DPAOs sludge neither nitrogen nor phosphorus removal was significantly affected at DO limited condition (0.5 mg/L DO). However, as DPAOs to nitrifiers population ratio was further increased to 1:4, the effect of low DO was found to be more significant on nitrification than P-removal. This signifies the competitive advantages of DPAOs over nitrifiers under DO limited condition.

Index Terms—Denitrifying phosphorus accumulation organisms (DPAOs), nitrifiers, low DO nutrient removal, DPAO-nitrifiers competition.

M. Zaman and G. Nakhla are with the Department of Chemical and Biochemical Engineering, Western University, 1151 Richmond Street, London, ON, N6A 3K7, Canada (e-mail: mzaman9@uwo.ca, gnakhla@uwo.ca).
X. Liu is with the Department of Civil and Environmental Engineering, Western University, 1151 Richmond Street, London, ON, N6A 3K7, Canada (e-mail: xliu625@uwo.ca).

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Cite: Masuduz Zaman, Xiaoguang Liu, and George Nakhla, "Impact of Dissolved Oxygen Concentration and DPAOs: Nitrifiers Population Ratio on Nutrient Removal in EBPR Process," International Journal of Environmental Science and Development vol. 10, no. 9, pp. 257-260, 2019.

Copyright © 2019 by the authors. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).