Abstract：
To reduce pollution and carbon emissions, a quantitative evaluation of the carbon footprint of the wastewater treatment processes is crucial. However, micro carbon element flow analysis is rarely focused considering treatment efficiency of different technology. In this research, a comprehensive carbon footprint analysis is established under the micro carbon element flow analysis and macro carbon footprint analysis based on life cycle assessment (LCA). Three wastewater treatment processes (i.e., anaerobic anoxic oxic, A2O; cyclic activated sludge technology, CAST; modified cyclic activated sludge technology, M-CAST) for low carbon source urban wastewater are selected. The micro key element flow analysis illustrated that carbon source mainly flows to the assimilation function to promote microorganism growth. The carbon footprint analysis illustrated that M-CAST as the optimal wastewater treatment process had the lowest global warming potential (GWP). The key to reduce carbon emissions is to limit electricity consumption in wastewater treatment processes. Under the comprehensive carbon footprint analysis, M-CAST has the lowest environmental impact with low carbon emissions. The sensitivity analysis results revealed that biotreatment section variables considerably reduced the environmental impact on the LCA and the GWP, followed by the sludge disposal section. With this research, the optimization scheme can guide wastewater treatment plants to optimize relevant treatment sections and reduce pollution and carbon emissions.
摘要：
为了减少污染和碳排放，对废水处理过程的碳足迹进行定量评估至关重要。然而,微碳元素流分析很少关注不同工艺的处理效率。在这项研究中,在基于生命周期评价(LCA)的微观碳元素流分析和宏观碳足迹分析基础上,建立了全面的碳足迹分析。三种废水处理工艺(即，厌氧缺氧氧，A2O；循环活性污泥技术，CAST；改良循环活性污泥技术，选择M-CAST）用于低碳源城市污水。微观关键元素流分析表明，碳源主要流向同化功能以促进微生物生长。碳足迹分析表明，M-CAST作为最佳的废水处理工艺具有最低的全球变暖潜能值（GWP）。减少碳排放的关键是限制废水处理过程中的电力消耗。在全面的碳足迹分析下，M-CAST对环境的影响最小，碳排放低。敏感性分析结果表明，生物处理部分变量大大降低了对LCA和GWP的环境影响，其次是污泥处置部分。通过这项研究,优化方案可以指导污水处理厂优化相关处理段,减少污染和碳排放。
