Cost-effective strategies can reduce water and energy requirements in China's wastewater treatment by 2035

Wastewater treatment is a key component in ensuring future water resource security. However, this process itself faces major challenges in water and energy consumption. Reducing these inputs at low cost without compromising wastewater treatment effectiveness is crucial for sustainable development. Here, we assess the water and energy footprint of wastewater treatment in China, using estimated data from 10,124 urban wastewater treatment plants and 90 cases. We show that the water and energy footprints of wastewater treatment in China have nearly tripled from 2009 to 2022. By aligning treatment process selection through multi-objective trade-offs, reductions can be effectively achieved. By 2035, China's wastewater treatment water footprint and energy footprint could be reduced by 16.1% and 25.6%, respectively, with investments below 8% of total treatment costs, while the removal remains stable. Our findings offer a broadly applicable framework to guide sustainable wastewater management and support progress toward the Sustainable Development Goals.