Water–energy–carbon coupling index assessment of aeration control and techno-economic analysis of hybrid renewable energy for wastewater treatment plant

Key Points

• The study aims to develop a framework for assessing the interactions between water quality, energy efficiency, and greenhouse gas emissions in wastewater treatment plants.
• Developed a Water–Energy–Carbon Coupling Index (WECCI) framework integrating aeration control and renewable energy.
• Utilized mixed-effects modeling to identify low-DO/high-NH3-N areas as greenhouse gas emission hotspots.
• Implemented WECCI–TOPSIS for scenario optimization under various policy priorities.
• Achieved up to 30.1% energy self-sufficiency with proposed hybrid renewable energy configurations.
• Quantified trade-offs between water quality and energy efficiency.
• Identified significant GHG emission hotspots in low-DO/high-NH3-N regions.