Yan Guoxin, Kenway Steven J, Lam Ka Leung, Lant Paul A
Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St. Lucia, QLD 4067, Australia.
Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St. Lucia, QLD 4067, Australia.
Water Res. 2025 May 1;275:123153. doi: 10.1016/j.watres.2025.123153. Epub 2025 Jan 17.
Urban water utilities are significant energy users and also key actors in decarbonisation. However, the integrated perspective of urban water supply and wastewater system emissions, the relevant driving forces, and the boundaries of inclusions or exclusions, are rarely discussed. This is due to widely disaggregated data, and complex issues regarding the boundary of the system being investigated. This work develops an innovative assessment approach to assess system-wide emissions. We investigate historical emissions from eight cities (representing 56 million people). This study answers the question: what are the emission trajectories of urban water supply and wastewater systems and influencing factors and the influence of system boundary inclusions? The results indicate that, in many systems, "additional" or "new" water sources such as desalination or long-distance water transfers can dominate the emissions trends. Inconsistent inclusion of infrastructure for these supplies complicates city comparisons. Additionally, clarity is needed on whether emissions from recycled water (potable and non-potable) is reported as water supply or wastewater emissions. The creation of water/wastewater-emission trajectories better illustrates trade-offs occurring with management - for example, water supply in Perth and Beijing. The trajectory also illustrates reductions achieved for 15 years, for example, water supply in San Diego (reducing 77 %) and wastewater in New York City, San Diego, Los Angeles and Tokyo (reducing 38, 44, 47, and 17 % respectively). Our integrated analysis method provides a new emphasis for more holistic management of the water cycle. By revealing system boundary issues in reporting and systematically assessing full water cycle emissions, we demonstrate how essential this is to enable comparison across complex systems and city and utility reporting schemes.
城市水务部门是能源消耗大户，也是脱碳的关键参与者。然而，城市供水和污水处理系统排放的综合视角、相关驱动因素以及包含或排除的边界却很少被讨论。这是由于数据广泛分散，以及所研究系统边界的复杂问题。这项工作开发了一种创新的评估方法来评估全系统排放。我们调查了八个城市（代表5600万人）的历史排放。本研究回答了以下问题：城市供水和污水处理系统的排放轨迹、影响因素以及系统边界包含情况的影响是什么？结果表明，在许多系统中，诸如海水淡化或长距离调水等“额外”或“新”水源可主导排放趋势。这些供水基础设施包含情况不一致使城市间比较变得复杂。此外，对于再生水（饮用水和非饮用水）排放是作为供水排放还是污水处理排放进行报告，需要明确。水/污水处理排放轨迹的创建能更好地说明管理中出现的权衡——例如珀斯和北京的供水情况。该轨迹还说明了15年来实现的减排情况，例如圣地亚哥的供水（减排77%）以及纽约市、圣地亚哥、洛杉矶和东京的污水处理（分别减排38%、44%、47%和17%）。我们的综合分析方法为更全面地管理水循环提供了新的重点。通过揭示报告中的系统边界问题并系统评估全水循环排放，我们证明了这对于跨复杂系统以及城市和公用事业报告方案进行比较是多么重要。
