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| Nitrogen removal capacity of simultaneously nitrifying and denitrifying bacteria（Alcaligenes faecalis WT14） in breeding wastewater |
| Received:March 23, 2020 |
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| KeyWord:heterotrophic nitrifying-aerobic denitrifying bacteria;simultaneous(de) nitrification;breeding wastewater;dissolved oxygen |
| Author Name | Affiliation | E-mail | | CHEN Jun-li | Key Laboratory of Agro-ecological Processes in Subtropical Regions, Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China
University of Chinese Academy of Sciences, Beijing 100049, China | | | ZHANG Shu-nan | Key Laboratory of Agro-ecological Processes in Subtropical Regions, Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China | | | Dai Gui-jin | Special Agricultural Industry Center in Fenghuang county of Hunan Province, Fenghuang 416200, China | | | ZHANG Miao-miao | Key Laboratory of Agro-ecological Processes in Subtropical Regions, Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China | zhangmiao0110@163.com | | WU Jin-shui | Key Laboratory of Agro-ecological Processes in Subtropical Regions, Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China
University of Chinese Academy of Sciences, Beijing 100049, China | | | LIU Feng | Key Laboratory of Agro-ecological Processes in Subtropical Regions, Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China | |
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| Abstract: |
| To investigate the controlling effect of dissolved oxygen(DO)on the nitrogen removal efficiency of heterotrophic nitrifying-aerobic denitrifying(HN-AD)bacteria, Alcaligenes faecalis strain WT14, an HN-AD bacterium, was newly isolated from a constructed wetland, and its heterotrophic nitrification-aerobic denitrification capacity was explored. The effects of different DO conditions on its removal capacity of NH4+-N and NO3--N were studied, and a two-stage, DO-controlled, fixed-bed reactor was established to analyze the effect of treatment with strain WT14 on breeding wastewater by DO control. Nitrogen balance experiments revealed that strain WT14 had an efficient and simultaneous nitrification-denitrification capacity; 92.10% of NH4+-N was converted into nitrogen-containing gas, 4.16% of NH4+-N was assimilated into intracellular nitrogen, and the presence of NH4+-N promoted the reduction in NO3--N. The DO control experiment showed that the NH4+-N and NO3--N removal capacities of strain WT14 were significantly related to the DO concentration. Low DO conditions inhibited the removal of NH4+-N but promoted that of NO3--N, which was in accordance with the Boltzmann model. The halfinhibitory concentrations of the NH4+-N and NO3--N removal capacities were 2.53 mg·L-1 and 5.40 mg·L-1 of DO, respectively. The maximum NH4+-N and NO3--N removal efficiencies of strain WT14 were 94.0% and 98.4%, respectively. Under two-stage aerobic conditions(4.00±0.30 mg·L-1 of DO), the removal efficiencies of NH4+-N, total nitrogen(TN), and chemical oxygen demand(COD)in aquacultural wastewater by strain WT14 were 99.3%, 90.5%, and 97.5%, respectively. Under continuous aerobic(4.00±0.30 mg·L-1 of DO)and hypoxic(0.50±0.10 mg·L-1 of DO)conditions, the removal efficiencies of NH4+-N, TN, and COD for breeding wastewater were 99.3%, 97.6%, and 98.2%, respectively, without the accumulation of NO3--N and NO2--N. |
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