Impact of coexistence of sludge flocs on nitrous oxide production in a granule-based nitrification system: A model-based evaluation

WATER RESEARCH

卷:170

Article

Liu, Yiwen^1,2  Ngo, Huu Hao²  Guo, Wenshan²  Wang, Dongbo^3,4  Peng, Lai⁵  Wei, Wei²  Ni, Bing-Jie² 

[1] Tianjin Univ, Sch Environm Sci & Engn, Tianjin 300350, Peoples R China

[2] Univ Technol Sydney, Ctr Technol Water & Wastewater, Sch Civil & Environm Engn, Sydney, NSW 2007, Australia

[3] Hunan Univ, Coll Environm Sci & Engn, Changsha 410082, Peoples R China

[4] Hunan Univ, Key Lab Environm Biol & Pollut Control, Minist Educ, Changsha 410082, Peoples R China

[5] Wuhan Univ Technol, Sch Resources & Environm Engn, Luoshi Rd 122, Wuhan 430070, Hubei, Peoples R China

关键词: Nitrifying system;    N2O production pathways;    N2O emission;    Granular sludge;    Sludge flocs;    Mathematical modelling;   

DOI  :  10.1016/j.watres.2019.115312

来源: Elsevier

【 摘 要 】

A common operational status of granule-based reactor is the inevitable coexistence of sludge flocs. Such hybrid system could have a profound impact on nitrous oxide (N2O) production in nitrifying process. In this work, a mathematical model is employed to evaluate the key role of the coexistence of sludge flocs on N2O production in a granule-based nitrifying system for the first time, by considering both nitrifier denitrification and hydroxylamine oxidation pathways. The modelling results show that the N2O production gradually decreases with the increase of the percentage of sludge flocs in the total biomass (10-60%). More N2O is tended to be generated in sludge flocs which has lower N2O production capacity compared to granular biomass, thus lowering the total N2O production. The relative contributions of two N2O production pathways are only affected by bulk dissolved oxygen (DO) for the sludge flocs in the hybrid system, whereas those are affected by both bulk DO and the fractions of sludge flocs for the granular biomass. The results reveal a substantial effect of the coexistence of sludge flocs on N2O production in granule-based nitrifying process, which should not be ignored in future design and operation. (C) 2019 Elsevier Ltd. All rights reserved.

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