No Laughing Matter - Global Lessons for Nitrous Oxide

Hayden Porter, Amanda Lake, Ariane Brotto, Aprilia Vellacott - Jacobs

Jose Porro - Cobalt Water Global

Mikkel Andersen - Unisense Environment

While water and wastewater sector greenhouse gas emissions make up just a fraction of New Zealand’s total emissions, they contribute significantly to the emissions footprints of our local councils who operate these assets. Councils are responding to the global climate crisis and New Zealand’s Net Zero Carbon Act by setting targets to reduce emissions; the three largest councils in New Zealand are targeting net zero emissions by 2050. Focus on direct process emissions of nitrous oxide and methane from wastewater treatment plants is becoming a focus as these emissions can contribute 50% or more of a council’s total emissions. 

Jacobs, Cobalt Water Global and Unisense Environment have been leading work globally on process emissions. This paper summarises our work in Europe, framed by the current state of science and recent Intergovernmental Panel on Climate Change (IPCC) guidelines and ongoing research. Using case studies from Denmark, the United Kingdom, and Netherlands we highlight where progressive European utilities are taking action to understand, quantify and mitigate process emissions through national and utility level programmes. A focus across the regions in the case studies has been on national/sector-wide emission factors and considering varied treatment types. Mitigation through facility level monitoring and evidenced based approaches show a pathway to contributing toward utilities’ net zero goals. We discuss synergies and opportunities to undertake similar work here to deliver climate action in the water sector for New Zealand.