Wastewater treatment solutions for climate mitigation ​

Wastewater is often overlooked in climate discussions, yet it is a powerful opportunity for climate action. 

Wastewater systems are a significant source of methane (CH₄) and nitrous oxide (N₂O), two highly potent greenhouse gases that remain largely under-reported in national climate strategies. At the same time, wastewater treatment plants can become climate solution hubs, reducing emissions while recovering valuable resources such as energy and nutrients. 

This first webinar in a four-part global series (running from April to October 2026) explored how the wastewater sector can contribute to climate mitigation and support the Global Methane Pledge goal of reducing emissions by 30% by 2030. Building on recent global milestones, including the UN-Water call to address wastewater emissions and new science from the UNEP-DHI report, the session will highlight practical solutions for monitoring, mitigation and policy action. 

Experts and practitioners from several countries and international organisations will share concrete examples of how countries are beginning to measure greenhouse gas emissions from wastewater, develop inventories, and identify mitigation opportunities.

The discussion will also explore how governments, utilities and partners can integrate wastewater mitigation into national climate strategies and Nationally Determined Contributions (NDCs). 

About the report

The ‘Wastewater treatment solutions for climate mitigation: a practical guide’ serves as a comprehensive resource for wastewater practitioners, policymakers, and researchers aiming to reduce greenhouse gas emissions in the sanitation sector. With wastewater treatment contributing up to a level of global emissions comparable to aviation and cement production, this timely guide emphasizes the urgent need to align sanitation goals with climate action. The technical guide provides detailed methodologies for monitoring and quantifying emissions, explores mitigation strategies through planning and process optimization, and highlights policy instruments and technologies that support the transition to net-zero wastewater treatment.

Read the technical report