Emissions of the very potent greenhouse gas nitrous oxide contribute often very much to the sum of greenhouse gas emissions from wastewater treatment with enhanced biological nitrogen removal. The Danish project LaGas aims to identify, implement and validate new control strategies to mitigate nitrous oxide emissions in wastewater treatment.

The Intergovernmental Panel on Climate Change (IPCC) highlights wastewater treatment as a significant point source of nitrous oxide emissions. Today, nitrous oxide is also the most dominant ozone destroying chemical from anthropogenic sources. However, the quantification of the emissions is very uncertain. The emission varies a lot between and at different wastewater treatment plants, and the challenges to make proper quantifications of the emissions are many. Nitrous oxide is produced as by- and intermediate products in the biological nitrogen removal processes nitrification and denitrification. Many different environmental factors affect the emissions.

When new microorganisms, techniques and control strategies regarding nitrogen removal processes are implemented to decrease energy and resource usage, one has to quantify potential nitrous oxide emissions. Otherwise the gain is lost by increased climate impact.

LaGas will perform a comprehensive and detailed study about the origin, mechanisms and modelling of nitrous oxide emissions and the different measurements techniques.

Project members from Sweden Water Research