title: Enhancing nitrogen removal in an Orbal oxidation ditch by optimization of oxygen supply: practice in a full-scale municipal wastewater treatment plant.
abstract: Seven different aeration modes, in which oxygen supply was changed by adjusting the number of aerators, were designed and applied in a full-scale municipal wastewater treatment plant with Orbal oxidation ditch to investigate the influence of dissolved oxygen (DO) on nitrogen removal performance. The full-scale experiment results of 574 days showed that nitrogen removal efficiency depended on the degree of nitrification and denitrification in the outer channel, which was the largest contributor for TN removal in the Orbal oxidation ditch. Appropriate aeration control in the outer channel was essential to balance nitrification and denitrification in the Orbal oxidation ditch. When DO was as low as about 0.2 mg/L in the outer channel, the highest TN removal efficiency of 75% was obtained. Microbial analysis confirmed that aerobic and anaerobic bacteria coexisted in the outer channel. The greater species diversity and more intensive activities of these bacteria in aeration Mode V may be responsible for the higher TN removal efficiency compared with Mode III. These results suggest that different aerated conditions in the Orbal oxidation ditch might have a significant effect on microbial community characteristics and nitrogen removal efficiencies.
authors.affiliation: Department of Water Pollution Control Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhou
authors.forename: Xuesong
authors.initials: X
authors.lastname: Guo
authors.forename: Yunping
authors.initials: Y
authors.lastname: Han
authors.forename: Junxin
authors.initials: J
authors.lastname: Liu
authors.forename: Jincheng
authors.initials: J
authors.lastname: Ren
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Yantao
authors.initials: Y
authors.lastname: Guo
mesh_terms: D001419:Bacteria / Q000302:isolation & purification; D001483:Base Sequence; D017931:DNA Primers; D004587:Electrophoresis, Agar Gel; D009584:Nitrogen / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D062065:Wastewater
chemical_list: D017931:DNA Primers; D009584:Nitrogen; D010100:Oxygen; D062065:Wastewater