2020 Fiscal Year Annual Research Report
Development of one-stage nitrogen removal and phosphorus recovery process
Project/Area Number |
20J21404
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Research Institution | Tohoku University |
Principal Investigator |
XUE YI 東北大学, 工学研究科, 特別研究員(DC1)
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Project Period (FY) |
2020-04-24 – 2023-03-31
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Keywords | anammox / biomineralization / phosphorus recovery / granulation |
Outline of Annual Research Achievements |
In my study, various anammox granule sizes are investigated for their properties and morphology. Such study were obtained because of an increased water content due to a drop in granule size. As for the removal of N and P, a lower specific anammox activity (SAA) was found along with a smaller granule size, and granules at a diameter of 1-2 mm were observed as the main contributor for the nitrogen removal rate of 48.4% and the phosphorus removal rate of 50%. Besides, the abundance of anammox bacteria, Candidatus Kuenenia stuttgartiensis in this case, dropped along with a smaller granule size. Based on the SEM-EDX results on granules and flocs, a growth pattern by biomineralization is proposed in this study, in which a simultaneous size enlargement of biofilms and HAP cores forms a structure of double-layer poly-pellets that were then encapsulated by biofilms for granulation. In addition, a sustainable multiplication mechanism was proposed, in which a two-step procedure facilitates the separation of embryo HAP crystals from the mother core via heterogeneous nucleation, and biofilms are obtained with the roles of microbial metabolism and shear stress to form flocs. Subsequently, the flocs grow according to the growth pattern for a new granule cycle.
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Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
最初の段階は実験を完了し、2つの論文を発表しました。 [1]Y. Xue, H. Ma, Z. Kong, Y. Guo, Y.Y. Li, Bulking and floatation of the anammox-HAP granule caused by low phosphate concentration in the anammox reactor of expanded granular sludge bed (EGSB), Bioresour. Technol. 310 (2020) 123421. https://doi.org/10.1016/j.biortech.2020.123421. [2]Y. Xue, H. Ma, Z. Kong, Y.-Y. Li, Formation Mechanism of hydroxyapatite encapsulation in Anammox-HAP Coupled Granular Sludge, Water Res. 193 (2021) 116861. https://doi.org/10.1016/j.watres.2021.116861. 第二は徐々に進んでいます。
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Strategy for Future Research Activity |
A main challenge for the application of anammox granular sludge is the hollowization inside, which would cause sludge wash-outs as a result of floatation, finally leading to unstable reactor performance. The formation of HAP core as carriers to fill in the internal cavities is essential to solve the problem, and such strategy can also achieve nitrogen removal and phosphorus recovery simultaneously.
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Research Products
(2 results)