Municipal wastewater treatment plants (WWTPs) are major urban energy consumers but also contain recoverable resources, including organic chemical energy, wastewater heat, nutrients, and other recoverable materials. Harnessing these resources could contribute to net-zero urban development, yet full-scale performance often falls below theoretical potential because of influent variability, climatic constraints, and plant-wide process interactions. Moreover, energy neutrality does not imply carbon neutrality, as fugitive CH4 and process N2O emissions can offset the climate benefits of energy recovery. Recovered materials also face product-specific health, chemical, regulatory, and market barriers. This review suggests that future studies should shift the focus from maximizing theoretical resource recovery to evaluating whether its benefits persist under real-world energy, greenhouse gas (GHG), effluent-quality, safety, economic, and infrastructure constraints. Evidence from pilot- and full-scale studies and system-level assessments is synthesized to compare major recovery pathways, identify theory-practice gaps and critical trade-offs, and evaluate technology combinations with realistic decarbonization potential. It also highlights the need for plant-wide optimization, standardized benchmarking, uncertainty-aware life-cycle assessment, and enabling policy frameworks to advance low-carbon municipal wastewater treatment systems.
- Open Access
- Review
From Urban Resource Sinks to Hubs of Materials for the Environment: Trade-Offs and Deployment Realities for Net-Zero Municipal Wastewater Systems
Author Information
Received: 28 July 2026 | Revised: 02 September 2026 | Accepted: 13 October 2026 | Published: 05 November 2026
Abstract
Keywords
municipal wastewater treatment | energy recovery | energy saving | carbon neutrality | resource circularity | sustainability | low-carbon systems
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