Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; Yangtze River Delta Branch, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Yiwu 322000, Zhejiang, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China.
Sci Total Environ. 2023 Jul 1;880:163335. doi: 10.1016/j.scitotenv.2023.163335. Epub 2023 Apr 6.
The issue of greenhouse gas (GHG) emissions resulting from the upgrading and reconstruction of municipal wastewater treatment plants (MWWTPs) along with improved water quality is receiving attention and research. There is an urgent need to explore the impact of upgrading and reconstruction on carbon footprint (CF) in order to address concerns that the upgrading and reconstruction will increase GHG emissions while improving water quality. Here we accounted for the CF of five MWWTPs in Zhejiang Province, China, before and after three different upgrading and reconstruction models - "Improving quality and efficiency" ("Mode I"), "Upgrading and renovation" ("Mode U") and "Improving quality and efficiency plus Upgrading and renovation" ("Mode I plus U"). The upgrading and reconstruction was found to not necessarily result in more GHG emissions. In contrast, the "Mode I" had a more significant advantage in terms of CF reduction (1.82-12.6 % reduction in CF). Overall, the ratio of indirect emissions to direct emissions (indirect emissions/direct emissions) and the amount of GHG emitted per unit of pollutant removed (CF、CF、CF) decreased, while both the carbon and energy neutral rates increased significantly (up to 33.29 % and 79.36 % respectively) after all three upgrading and reconstruction modes. In addition, the wastewater treatment efficiency and capacity are the main factors that affect the level of carbon emission. The results of this study can provide a calculation model that can be used for other similar MWWTPs during the upgrading and reconstruction processes. More importantly, it can provide a new research perspective as well as valuable information to revisit the impact of upgrading and reconstruction in MWWTPs on GHG emissions.
城市污水处理厂（MWWTP）升级改造和提高水质所带来的温室气体（GHG）排放问题引起了人们的关注和研究。为了解决升级改造会在提高水质的同时增加 GHG 排放的担忧，迫切需要探索升级改造对碳足迹（CF）的影响。在这里，我们考虑了中国浙江省的五座 MWWTP 在三种不同的升级改造模式（“提高质量和效率”（“模式 I”）、“升级和翻新”（“模式 U”）和“提高质量和效率加升级和翻新”（“模式 I 加 U”）前后的 CF。研究发现，升级改造不一定会导致更多的 GHG 排放。相比之下，“模式 I”在 CF 减排方面具有更显著的优势（CF 减少 1.82-12.6%）。总体而言，间接排放与直接排放的比例（间接排放/直接排放）和每去除单位污染物排放的 GHG 量（CF、CF、CF）均有所下降，而碳和能源中性率则显著增加（分别高达 33.29%和 79.36%）。此外，污水处理效率和处理能力是影响碳排放量水平的主要因素。本研究的结果可为其他类似 MWWTP 在升级改造过程中提供计算模型。更重要的是，它可以为重新审视 MWWTP 升级改造对 GHG 排放的影响提供新的研究视角和有价值的信息。
