China's Municipal Wastewater System Emissions on the Rise

Researchers from the Chinese Academy for Environmental Planning have reported a significant increase in methane emissions from China's municipal wastewater system. According to the study, the system releases approximately 911 Gg of methane, with wastewater collection and sludge disposal being the dominant contributors. The study highlights the need for fine maintenance of sewer pipelines, appropriate matching of sewers and treatment facilities, and transition in sludge disposal methods to mitigate pollution and emissions. The research also identifies a negative linear relationship between the sewage collection rate and per capita methane emissions in the wastewater sector at the city-level.

Key Takeaways:

• The municipal wastewater system in China releases approximately 911 Gg of methane, with wastewater collection and sludge disposal being the dominant contributors.
• The study highlights the need for fine maintenance of sewer pipelines, appropriate matching of sewers and treatment facilities, and transition in sludge disposal methods to mitigate pollution and emissions.
• A negative linear relationship was identified between the sewage collection rate and per capita methane emissions in the wastewater sector at the city-level.
• The study was conducted by researchers from the Chinese Academy for Environmental Planning, including Daming Wei, Han Gao, Peng Zhang, Wenjing Zhang, Gang Yan, Wenbo Xue, Yue Zhao, Weili Ye, Liqing Guo, and Shuojia Peng.
• The study provides a nationwide city-resolved estimate of methane emission from municipal wastewater system in China.
• Wastewater collection (56.8%) and sludge disposal (34.6%) were the dominant contributors to nationwide emissions.

Statistics:

• 911 Gg: the total amount of methane emissions from China's municipal wastewater system.
• 56.8%: the percentage of wastewater collection contributing to nationwide emissions.
• 34.6%: the percentage of sludge disposal contributing to nationwide emissions.
• -0.21: slope of the negative linear relationship between the sewage collection rate and per capita methane emissions in the wastewater sector at the city-level.

Sources:

• Methane Emissions Features From China's Municipal Wastewater Management, Based On the Whole-process Evaluation of Collection, Treatment and Discharge. Journal of Cleaner Production, 2025;509.
• Chinese Academy for Environmental Planning
• Daming Wei, Han Gao, Peng Zhang, Wenjing Zhang, Gang Yan, Wenbo Xue, Yue Zhao, Weili Ye, Liqing Guo, Shuojia Peng
• NewsRx. Study Data from Chinese Academy for Environmental Planning Update Understanding of Environment and Sustainability Research (Methane Emissions Features From China's Municipal Wastewater Management, Based On the Whole-process Evaluation of ...). Global Warming Focus. June 9, 2025; p 718.