China’s enhanced wastewater treatment capacity may accelerate greenhouse gas emissions from rural domestic pollution

The diminution of the benefits of domestic pollution control by greenhouse gas (GHG) emissions has received considerable attention. Emission factors related to the construction and operation of wastewater treatment systems have been well characterized in urban settings but far less so in rural areas. To address this gap, we developed an integrative modeling framework that quantifies the entire chain of rural domestic pollution processes together with the associated GHG emissions. Our analysis suggests that the control of China’s rural domestic pollution has realized a threefold increase over the past decade, resulting in a decline of carbon (C), nitrogen (N), and phosphorus (P) discharge to surface waters by 1158 Gg, 316 Gg, and 43 Gg, respectively. However, GHG emissions have also discernibly increased from 26.7 Tg to 31.4 Tg. Even though over 70% of China’s rural domestic pollution is still being discharged untreated, GHG emissions from wastewater treatment systems have become prevalent and currently account for more than 60% of total GHG emissions from rural areas. Considering the on-going construction of numerous new wastewater treatment systems in rural areas, enhancing wastewater treatment capacity, strengthening resource recovery, optimizing dietary patterns of the public, and promoting the use of clean energy are recommended to balance the trade-offs between environmental pollution abatement and climate change mitigation.