Seasonality of nitrous oxide emissions at six full-scale wastewater treatment plants

• DOI: 10.2166/wst.2023.420
• Publication Date: 2023-12-25T09:25:58Z
• Authors: Milla Sieranen; Helena Hilander; Henri Haimi; Timo Larsson; Anna Kuokkanen; Anna Mikola
• Keywords: Nitrous oxide; Seasonality

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