碳中和愿景下的污水处理厂温室气体排放情景模拟研究

污水处理厂运行过程中大量释放甲烷（CH₄）和氧化亚氮（N₂O),是重要的人为温室气体排放源。基于2005—2015年统计资料和IPCC核算方法,估算了2005—2015年中国生活污水处理厂CH₄和N₂O排放,分析了其排放特征和影响因素;依据碳中和愿景设定3种减排情景（低减排、中减排和高减排),并预估了2020—2050年排放趋势和时空变化。结果表明：2005—2015年间污水处理厂温室气体排放量呈稳定增长趋势,CH₄从1135.37万t CO₂e上升至1501.45万t CO₂e,N₂O从2651.08万t CO₂e上升为2787.05万t CO₂e,年均增速分别为2.8%和0.5%。3种减排情景下,2020—2050年CH₄和N₂O排放量时间上呈先增后减趋势,低减排情景下CH₄和N₂O排放量分别于2036年和2025年达到峰值,分别为2431万和2819万t CO₂e;中减排情景和高减排情景下CH₄峰值点分别出现在2027和2025年,而N₂O排放峰值均出现在2025年。2050年中减排和高减排情景下CH₄排放量相较于低减排情景减排率约为47%和94%;2050年低减排、中减排和高减排情景下N₂O排放量相较于2015年分别减排了12%、53%和95%。CH₄和N₂O排放量在空间上差异显著,华东地区排放量高,西北地区排放量低,东南区域所在省份排放量整体高于西北区域省份。影响因素中的经济发展程度与温室气体排放量密切相关。

Simulation research on greenhouse gas emissions from wastewater treatment plants under the vision of carbon neutrality

Large amounts of methane (CH₄) and nitrous oxide (N₂O) are released during the operation of sewage treatment plants, which are important sources of man-made greenhouse gas emissions. Based on 2005-2015 statistical data and IPCC accounting methods, the CH₄ and N₂O emissions from domestic sewage treatment plants in China from 2005 to 2015 were estimated, characteristics and influencing factors were analyzed. Three emission reduction scenarios (low emission reduction, medium emission reduction and high emission reduction) were set based on the carbon neutral background, and emission trends and temporal and spatial changes from 2020 to 2050 were estimated. The results showed that the greenhouse gas emissions of sewage treatment plants increased steadily from 2005 to 2015. CH₄ increased from 11.35 Mt CO₂e to 15.01 Mt CO₂e, and N₂O increased from 26.51 Mt CO₂e to 27.87 Mt CO₂e, the average annual growth rate was 2.8% and 0.5%, respectively. Under the three emission reduction scenarios, CH₄ and N₂O emissions from 2020 to 2050 show a trend of increase first and then decrease, and CH₄ and N₂O emissions under the low emission reduction scenario will peak in 2036 and 2025, respectively, with 24.31 Mt CO₂e and 28.19 Mt CO₂e; CH₄ peaks in the medium and high emission reduction scenarios will occur in 2027 and 2025, respectively, while the peak N₂O emissions will both occur in 2025. Compared with the low emission reduction scenario, the respective emission reduction rates of CH₄ emissions under the medium and high emission reduction scenarios are about 47% and 94% in 2050. N₂O emissions under the low, medium and high emission reduction scenarios in 2050 will be reduced by 12%, 53% and 95% respectively compared with 2015. There are significantly spatial differences in the emissions of CH₄ and N₂O. East China has the highest emissions and Northwest China has the lowest ones. The overall emission pattern is that the provinces in the southeast are higher than those in the northwest. Among the influencing factors, the level of economic development is closely related to greenhouse gas emissions.