Characteristics of N2O Accumulation during the Endogenous Denitrification of Nitrite
Ding Xiaoqian 1  
,   Zhao Jianqiang 2, 3  
,   Hu Bo 4  
,   Wang Sha 2  
,   Li Xiaoling 4  
,   Lan Lan 2  
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School of Architecture and Civil Engineering, Xi’an University of Science and Technology, Xi’an, Shaanxi, China
School of Environmental Science and Engineering, Chang’an University, Xi’an, Shaanxi, China
Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region (Chang’an University), Ministry of Education, Xi’an, Shaanxi, China
School of Civil Engineering, Chang’an University, Xi’an, Shaanxi, China
Zhao Jianqiang   

Chang’an University, China
Submission date: 2018-12-17
Final revision date: 2019-02-11
Acceptance date: 2019-02-23
Online publication date: 2019-09-10
Publication date: 2019-12-09
Pol. J. Environ. Stud. 2020;29(1):901–908
Emissions of nitrous oxide (N2O) occur during the biological denitrification process, but a few studies have focused on N2O emissions during denitrification under endogenous conditions. To investigate the characteristics of N2O emissions and accumulation during the process of endogenous denitrification, experiments were carried out to explore the action mechanisms of nitrite (NO2-) on N2O production during the denitrification process, with intracellular polymers serving as the electron donor. The results indicated that the N2O production factors increased with increasing initial NO2--N concentration due to the slow biological degradation of the intracellular polymers and the inhibitions of free nitrite acid (FNA) on the activity of nitrous oxide reductase (Nos). When the NO2--N concentration was further increased, exceeding 100 mg N/L, the N2O production factors decreased, potentially on account of the inhibition of increased FNA on the activities of nitrite reductase (Nir) and nitric oxide reductase (Nor), resulting in declined nitrite removal efficiency and increased NO production. Studying the mechanisms of N2O accumulation during endogenous denitrification is beneficial for controlling N2O emissions during the biological nitrogen removal process in wastewater treatment.