Long-term Assessment of N2O Emission Factor in Full-scale Oxidation Ditch Reactor Considering Spatiotemporal Distribution

Q3 Environmental Science

Journal of Water and Environment Technology Pub Date : 2021-01-01 DOI:10.2965/JWET.20-145

S. Otomo, A. Terada, Yuyou Li, Kazuya Nishitoba, F. Takakai, K. Okano, N. Miyata, S. Masuda

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Abstract

In full-scale sewage treatment plants, long-term and high-frequency monitoring is required to mitigate nitrous oxide (N2O) emissions. In this study, the profile of the dissolved N2O concentration in a full-scale oxidation ditch reactor was investigated to determine the variation of the N2O emission factor. It was found that the concentration of dissolved N2O depended on microbial activity, which is affected by water temperature, dissolved oxygen concentration, and the dimensional relationship between the rotator and the inflow point. In the reactor, higher transcription levels of amoA mRNA and lower transcription levels of clade II type nosZ mRNA may be associated with N2O production. The emission factor for removed dissolved inorganic nitrogen presented a mean value of 0.86% and a median of 0.19%. When N2O production was promoted, gasification from the water surface was the most significant emission source, accounting for 52% of the total N2O emitted, on average. The N2O emission factor was often lower than 0.01% during stable operation; however, this factor was subject to sudden increases caused by nitrite accumulation.

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考虑时空分布的全尺寸氧化沟反应器N2O排放因子的长期评价

在全面的污水处理厂，需要长期和高频监测，以减少一氧化二氮(N2O)的排放。在本研究中，研究了全尺寸氧化沟反应器中溶解N2O浓度的分布，以确定N2O排放因子的变化。研究发现，溶解N2O浓度与微生物活性有关，微生物活性受水温、溶解氧浓度、旋转器与入水点的尺寸关系等因素的影响。在反应器中，较高的amoA mRNA转录水平和较低的II枝型nosZ mRNA转录水平可能与N2O的产生有关。去除溶解态无机氮的排放因子均值为0.86%，中位数为0.19%。在促进N2O生产时，水面气化是最重要的排放源，平均占N2O总排放量的52%。稳定运行时，N2O排放系数往往低于0.01%;但由于亚硝酸盐的积累，该因子会突然增加。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Water and Environment Technology Environmental Science-Water Science and Technology

CiteScore

1.80

自引率

0.00%

发文量

审稿时长

43 weeks

期刊介绍： The Journal of Water and Environment Technology is an Open Access, fully peer-reviewed international journal for all aspects of the science, technology and management of water and the environment. The journal’s articles are clearly placed in a broader context to be relevant and interesting to our global audience of researchers, engineers, water technologists, and policy makers. JWET is the official journal of the Japan Society on Water Environment (JSWE) published in English, and welcomes submissions that take basic, applied or modeling approaches to the interesting issues facing the field. Topics can include, but are not limited to: water environment, soil and groundwater, drinking water, biological treatment, physicochemical treatment, sludge and solid waste, toxicity, public health and risk assessment, test and analytical methods, environmental education and other issues. JWET also welcomes seminal studies that help lay the foundations for future research in the field. JWET is committed to an ethical, fair and rapid peer-review process. It is published six times per year. It has two article types: Original Articles and Review Articles.