基于系统动力学模型的城市生活污水处理系统的甲烷排放特征及减排潜力分析

Methane emission characteristics and emission reduction potential analysis of urban domestic wastewater treatment system based on system dynamics model

为全面了解我国城市生活污水处理系统的甲烷排放现状及未来趋势,根据政府间气候变化专门委员会(IPCC)清单计算方法核算了2000—2015年我国生活污水处理系统的甲烷排放量。基于嵌入中国生活污水处理系统甲烷排放IPCC清单计算方法的系统动力学(SD)模型,模拟分析了2015—2050年基线情景和7种减排情景下的甲烷排放达峰和减排潜力。结果表明:我国生活污水处理系统甲烷排放总量从2000年的32.15×10^(4)t升至2015年64.78×10^(4)t,其中,污水处理过程中的甲烷排放量增长迅速,生活污水直接排入自然水体及经过处理后排放的甲烷排放量无明显增长;在模拟时段(2015—2050年)内,基线情景、节约用水情景、污水回用情景和节水回用情景中未出现生活污水处理系统甲烷排放峰值,在污水产生源头采取减排措施只能减缓增长速度,无法达到甲烷排放峰值;不同情景下的甲烷排放达峰时间及峰值不同,单一减排情景下的甲烷排放峰值出现在2035年后,而组合减排情景的峰值出现在2035年前,其中全程减排情景峰值出现在2024年;单一减排情景中污水回用减排潜力较好,可将其作为减排重点方向;而组合减排情景中全程减排情景具有最大减排潜力。本研究表明,未来生活污水处理系统甲烷排放量仍呈不断上升趋势,采用多手段协同减排可实现预期时间内污水处理系统甲烷排放达峰.

In order to comprehensively understand the current situation and future trends of methane emissions from urban domestic wastewater treatment systems in China, methane emissions released from domestic wastewater treatment systems in China during 2000-2015 were accounted for according to the Intergovernmental Panel on Climate Change(IPCC) inventory calculation methodology. Based on a system dynamics model(SD) embedded in the IPCC inventory calculation method for methane emissions from domestic wastewater treatment systems in China, the methane emissions peaking and reduction potential were simulated and analyzed for the baseline scenario and seven reduction scenarios from 2015-2050. The results showed that: the total methane emission from domestic wastewater treatment system in China rose from32.15×10^(4) t in 2000 to 64.78×10^(4) t in 2015, among which the methane emission from wastewater treatment process grew rapidly, and the methane emission from domestic wastewater discharged directly into natural water bodies and after treatment did not grow significantly. During the simulation period of 2015-2050, the methane emission peakof domestic wastewater treatment system did not occur in the baseline scenario, water conservation scenario, wastewater reuse scenario and water conservation and reuse treatment scenario, and emission reduction measures at the source of wastewater generation could only slow down the growth rate,but could not reach the peak methane emission.The peak time and peak of methane emissions in different scenarios were different., with peak methane emissions occurring after 2035 for the single reduction scenario and before 2030 for the combined reduction scenario, and the peak of the whole emission reduction scenario occurring in 2024. In the single abatement scenario, the reuse of wastewater had good emission reduction potential and can be regarded as the key direction of emission reduction direction.while in the combination emission of reduction scenarios, the whole emission reduction scenario had the greatest potential for emission reduction. The study showed that methane emissions from domestic wastewater treatment systems would continue to increase in the future, and the use of multiple means of synergistic emission reduction could achieve peak methane emissions from wastewater treatment systems within the expected time frame.