Abstract Nitrous oxide (N2O) is an ozone-depleting greenhouse gas that contributes significantly to the carbon footprint of a wastewater treatment plant (WWTP). Plant-specific measurement campaigns are required to reliably quantify the emission level that has been found to significantly vary between WWTPs. In this study, the N2O emissions were quantified from five full-scale WWTPs during 4- to 19-day measurement campaigns conducted under both cold period conditions (water temperature below 12 °C) and warm period conditions (water temperature from 12 to 20 °C). The measurement data were studied alongside long-term monitoring data from a sixth WWTP. The calculated emission factors (EFs) varied from near 0 to 1.8% relative to the influent total nitrogen load. The results confirmed a significant seasonality of N2O emissions as well as a notable variation between WWTPs in the emission level, which a single fixed EF cannot represent. Wastewater temperature was one explanatory factor for the emission seasonality. Both low and high emissions were measured from denitrifying–nitrifying activated sludge (AS) processes, while the emissions from only nitrifying AS processes were consistently high. Nitrite (NO2-) at the end of the aerobic zones of the AS process was linked to the variability in N2O emissions during the cold period.

中文翻译：

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六座大型污水处理厂一氧化二氮排放的季节性

摘要一氧化二氮 (N2O) 是一种消耗臭氧的温室气体，对废水处理厂 (WWTP) 的碳足迹影响很大。需要针对工厂进行测量活动，以可靠地量化已发现各污水处理厂之间存在显着差异的排放水平。在本研究中，在寒冷时期条件（水温低于 12 °C）和暖期条件（水温在 12 至 20 °C 之间）进行了 4 至 19 天的测量活动，对五个全规模污水处理厂的 N2O 排放进行了量化。 C）。测量数据与第六个污水处理厂的长期监测数据一起进行了研究。计算得出的排放因子 (EF) 相对于进水总氮负荷的变化范围约为 0% 至 1.8%。结果证实了 N2O 排放具有显着的季节性，并且各污水处理厂之间的排放水平存在显着差异，这是单个固定 EF 无法代表的。废水温度是排放季节性的解释因素之一。反硝化-硝化活性污泥 (AS) 工艺的排放量均较低和较高，而仅硝化 AS 工艺的排放量始终较高。AS 过程好氧区末端的亚硝酸盐 (NO2-) 与寒冷时期 N2O 排放量的变化有关。