Thermal use of urban wastewater: Some case studies
Urban sanitation networks in the 21st century must go beyond transporting and treating wastewater; they should also prioritize energy efficiency. Wastewater, accounting for over 70 % of water consumption, is collected through sewage systems and treated at wastewater treatment plants (WWTPs) before d...
| Autores: | , , , , |
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| Formato: | artículo |
| Fecha de publicación: | 2025 |
| País: | España |
| Recursos: | Universidad de Oviedo (UNIOVI) |
| Repositorio: | RUO. Repositorio Institucional de la Universidad de Oviedo |
| Idioma: | inglés |
| OAI Identifier: | oai:dnet:ruo_________::07c4d6142dd4c7f22f086fd590cceffd |
| Acesso em linha: | https://hdl.handle.net/10651/83218 https://dx.doi.org/10.1016/J.EGYR.2025.12.013 |
| Access Level: | acceso abierto |
| Palavra-chave: | Circular economy Heat pump Sludge drying Wastewater heat recovery |
| Resumo: | Urban sanitation networks in the 21st century must go beyond transporting and treating wastewater; they should also prioritize energy efficiency. Wastewater, accounting for over 70 % of water consumption, is collected through sewage systems and treated at wastewater treatment plants (WWTPs) before discharge. With temperatures between 10 and 23 °C, it represents a valuable thermal energy source. This study explores two approaches: drying sludge using treated WWTP effluent via heat pumps and recovering heat from urban sewers for building heating. In the first case, a WWTP treating 7045 m³ day−1 employed a 7.2–10.4 kW water-to-water heat pump at 45 °C (COP 4.2–4.5), reducing sludge moisture from 78.6 % to below 30 % and cutting disposal costs by €15,414 year−1. The €15,000–€16,000 investment was recovered in 2.2–3 years, yielding an IRR above 40 %. In the second case, heat from a sewer collector (300 L s−1, 19 °C) was used to heat an 8500 m² sports center. Three 140 kW heat pumps delivered 420 kW, reducing CO₂ emissions by 150 t year−1 and heating costs by €44,336 year−1, with a 2.5-year payback (excluding the cost of installing underfloor heating). These results show that wastewater heat recovery can provide reliable, cost-effective, and sustainable thermal energy, supporting urban energy efficiency and the circular economy, and promoting the vision of a globally applicable “sustainable city.” |
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