This paper highlight the following facts and core element for improvement regarding monitoring and mitigation of process gas emissions in wastewater treatment plants:

• Emissions of process gases, i.e., nitrous oxide (N2O) and methane (CH4), from wastewater and sludge treatment make up 60-70% of the GHG from wastewater treatment plants.
• N2O emissions represent a global warming potential 273 times higher than that of carbon dioxide.
• Technologies to monitor and mitigate N2O emissions have been developed in last 2 decades and successful case studies of their application are available in this paper.
• The revision of the Urban Wastewater Treatment Directive presents an important opportunity to address the monitoring and mitigation of N2O emissions, paving the way for the wastewater treatment sector’s
contribution to EU’s Climate Law targets.