基于LCA的AAO与AO污水处理工艺比较

发布时间：2018-06-22 08:32

本文选题：污水处理 + AO工艺与AAO工艺比较　；参考：《大连理工大学》2015年硕士论文

【摘要】：污水处理是一项环保工程,是将含有高污染物的污水经过处理达到排放标准后排放,减少了污染物的排放量,保护了水环境。同时,污水处理又是一项高能耗的工程,需要消耗大量的能源,还可能产生二次污染,比如恶臭、噪声和污泥等。传统的评估和选择污水处理工艺的方法,未能充分考虑不同工艺对环境产生的总负荷,仅仅在技术和经济方面进行考虑和比选,也具有一定的局限性,无法做到以全面的环境负荷去评价城市污水的污染问题。本文拟通过分析案例污水厂改造前后的工艺参数变化,尝试建立一种较全面的比较和评估污水厂污水处理工艺、方案的方法。生命周期评价(LCA)是一种新兴的、具有生命力和发展前景的环境管理工具,在国际上备受关注,正在越来越多地被应用到各个领域。本文选用生命周期评价的方法,借助GaBi软件的辅助,对案例污水处理厂改造前的A/O工艺和改造后的A/A/O工艺进行生命周期的比较分析,得出结论：案例污水处理厂改造后的A/A/O工艺中来自富营养化潜力和海洋水生生态毒性的环境影响要明显低于改造前的A/O工艺,而来自非生物枯竭因子、非生物消耗化石燃料、酸化潜力、淡水水生生态毒性、人类潜在毒性和潜在生态毒性的环境影响略低于改造前的A/O工艺,同时,来自全球变暖潜能、臭氧层损耗潜力和臭氧层创造潜力的环境影响略高于改造前的A/O工艺。在所研究的环境影响类别中,来自海洋水生生态毒性的环境影响贡献最为显著,且环境影响的贡献值A/A/O工艺低于A/O工艺；其次是全球变暖潜能的环境影响贡献略高,且改造前后没有显著变化；其它环境影响类别的环境影响贡献很小。通过对两种工艺的比较和分析得知,改造后的A/A/O工艺优于改造前的A/O工艺。为了进一步减少污水处理厂的环境影响,使得其对环境造成的影响更小,提出改善建议：污水处理厂实现减排的同时,也实现节能降耗,可以采用根据溶解氧实时调控曝气量,使用水源热泵等方式节约用电,尽可能地减少电能的消耗,以减少其所带来的环境负荷；同时,化学药剂的采购和使用应尽量高效,以减少化学药品的用量,减少其所带来的环境负荷；尽可能地增加污水回用量,节约用水,以增加其环境正效应：在有条件的情况下,尽量考虑污泥厌氧消化能源回用以及污泥N、P的回收,尽可能地减少能源和资源的消耗,带来环境正效应。
[Abstract]:Sewage treatment is an environmental protection project. It can reduce the discharge of pollutants and protect the water environment by treating the sewage containing high pollutants to meet the discharge standard. At the same time, sewage treatment is a high energy consumption project, which needs a lot of energy consumption, and may produce secondary pollution, such as odor, noise and sludge. The traditional methods of evaluating and selecting wastewater treatment processes, which fail to fully take into account the total load of different processes on the environment, only consider and compare the technical and economic aspects, also have some limitations. It is impossible to evaluate the pollution of urban sewage with comprehensive environmental load. This paper attempts to establish a more comprehensive method to compare and evaluate the wastewater treatment process and scheme by analyzing the change of technological parameters before and after the transformation of the wastewater treatment plant. Life cycle assessment (LCA) is a new environmental management tool with vitality and development prospects. It has attracted much attention in the world and is being applied to more and more fields. In this paper, the life cycle of A / O process before revamping and A / O process after revamping is compared and analyzed with the aid of Gabi software. It is concluded that the environmental impact from eutrophication potential and marine aquatic ecological toxicity in the modified A- / O process in the case sewage treatment plant is significantly lower than that in the prior A- / O process, but comes from abiotic depletion factors and abiotic consumption of fossil fuels. The environmental impacts of acidification potential, freshwater aquatic ecotoxicity, human potential toxicity and potential ecological toxicity are slightly lower than those of the pre-revamped A- / O process and, at the same time, from global warming potential. The environmental impact of ozone layer depletion potential and ozone layer creation potential is slightly higher than that of the pre-revamped A- / O process. Among the environmental impact categories studied, the environmental impact from marine aquatic ecological toxicity was the most significant, and the contribution value of the environmental impact was lower than that of the A- / O process, followed by the contribution of the global warming potential to the environmental impact. There is no significant change before and after transformation, and the contribution of other environmental impact categories is very small. Through the comparison and analysis of the two processes, it is found that the modified A / O process is superior to the pre-revamped A / O process. In order to further reduce the environmental impact of the wastewater treatment plant and make the environmental impact smaller, the paper puts forward some suggestions for improvement: while reducing emissions, the wastewater treatment plant can also realize energy saving and consumption reduction, so the aeration rate can be adjusted in real time according to the dissolved oxygen. The use of water source heat pumps and other ways to save electricity and minimize the consumption of electricity in order to reduce the environmental load it brings; at the same time, the purchase and use of chemicals should be as efficient as possible in order to reduce the amount of chemicals used, Reduce its environmental load; increase the amount of wastewater reused as much as possible and save water to increase its positive environmental effects: when conditions are available, try to consider sludge anaerobic digestion energy reuse and sludge NNP recovery, Reduce energy and resource consumption as much as possible and bring about positive environmental effects.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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