Methane (CH 4 ) and nitrous oxide (N 2 O), two powerful non‑carbon‑dioxide greenhouse gases, drive global climate warming. China’s wastewater treatment sector ranks as the nation’s fourth‑largest source for both gases. Wastewater treatment has become a key priority area for industrial decarbonization, following energy, transportation, and buildings, and emerging as a crucial lever for advancing synergistic pollution and carbon-emission mitigation. Consequently, accurate, high‑resolution emission data are essential to deliver practical mitigation policies.
A research team led by professor Xu Zhao from Institute of Blue and Green Development, Shandong University, constructed a high‑spatiotemporal‑resolution emission inventory for Chinese wastewater treatment plants spanning 2000‑2024. By combining top‑down provincial statistics and bottom‑up plant‑level operational records of 4550 facilities, the group generated a refined emission‑factor database differentiating wastewater types and treatment technologies. The dataset is gridded at 0.1° × 0.1°, and the derived inventory data are publicly available via Figshare.
The team published their research in Carbonsphere on September 18, 2026.
“We develop a long-term dataset that captures the dynamic evolution of emissions throughout China’s rapid urbanization and industrial restructuring. By integrating macro-level statistics with micro-level, plant-scale observations, our approach helps reduce estimation biases.” said Xu Zhao, corresponding author of the study. Prof. Zhao is also a Principal Investigator of a Major Grant of the National Social Science Fund of China; Taishan Distinguished Professor of Shandong Province.
The results show national non‑CO 2 emissions from wastewater plants climbed until 2015 before steadily declining up to 2024. Hotspot zones expanded from eastern China toward central regions. A small subset of facilities dominates emissions, the top 10 % of wastewater treatment plants contribute about 60 % of total CH 4 and N 2 O emissions and are often geographically clustered. Targeted regulation of these super‑emitters offers an economical path for cutting greenhouse‑gas release.
Treatment technology and plant scale are key controllable drivers of emission intensity. Anaerobic processes produce CH 4 intensities over seven times higher than typical aerobic processes. By contrast, N 2 O emissions are less sensitive to technical configurations and depend mainly on influent nitrogen loads.
“The concentrated distribution of super emitting plants makes regional scale joint governance feasible. Upgrading processes and unified operation maintenance for clustered high emission sites can lower overall abatement costs substantially,” explained Huiwen Yang, first author.
This study clarifies spatiotemporal patterns and controllable influencing factors of wastewater‑related non‑CO₂ emissions. The dataset supports region‑tailored climate policies and advances synergistic pollution and carbon reduction for China’s wastewater sector.
Other contributors include Hui-wen Yang, Yue Zhu from Institute of Blue and Green Development, Shandong University.
This work was supported by the National Key R&D Program of China (Grant No. 2023YFE0113000), the National Social Science Foundation of China (Grant No. 25&ZD166), the National Natural Science Foundation of China (Grant No. 72074136), the Taishan Scholar Youth Expert Program of Shandong Province (Grant No. tsqn202103020), and Shandong Provincial Natural Science Foundation (Grant No. ZR2024MG008).
DOI Link: https://doi.org/10.26599/CS.2026.9510009
About Carbonsphere :
Carbonsphere is an international open-access journal jointly sponsored by Qinghai University and Tsinghua University, published by Tsinghua University Press, and independently operated on the SciOpen platform. It is served as honorary editor-in-chief by Professor Hans Joachim Schellnhuber, academician of the German National Academy of Sciences, Director General of the International Institute for Applied Systems Analysis (IIASA), renowned climate system scientist, and founding director of the Potsdam Institute for Climate Impact Research (PIK). Professor Liu Zhu from Tsinghua University's Department of Earth Science and senior researcher at Harvard University serves as the editor-in-chief. Carbonsphere carries a unique mission and value. It is not only an academic window for carbon cycle science but also a link for addressing global climate challenges, with the ultimate goal of curbing carbon emissions and supporting a green future, and dedicated to promoting global low-carbon development through every research achievement.
Carbonsphere
High-spatiotemporal-resolution mapping of non-carbon dioxide emission hotspots from China’s wastewater treatment plants
18-Sep-2026