基于LCA的污水处理系统的环境影响评价研究

发布时间：2018-10-14 11:26

【摘要】：污水处理是高污染、高能耗的行业,其运行过程会造成较大的酸化效应和温室效应等问题,而环境评价可以有效地对其使用的工艺可能造成的环境影响进行分析、预测和评估,提出预防或者减轻不良环境影响的对策和措施,实现“节能、降耗、减污、增效”的目标。但是由于目前国内对污水处理系统的评价不够全面,易受主观因素影响,导致污水处理系统的环境影响评价方法存在一定局限性。为完善评价的方法,本文将生命周期评价(Life Cycle Assessment, LCA)理论应用于污水处理系统的环境评价过程,用于评价污水处理系统中不同工艺流程的环境影响,从而为今后确定污染治理重点和节能减排提供技术支持。(1)运用生命周期评价方法,构建污水处理系统的影响评价模型。确定研究边界范围,追溯系统的上游工段,构建全过程的生命周期清单,将污水处理系统分为污水处理阶段、运输阶段、污泥处置阶段进行环境影响评价。(2)采用CML-Nov.2010评估模型中的4项环境影响指标,包括富营养化潜值、酸化潜值、全球变暖潜值、人体毒性潜值,对污水处理系统边界内的环境影响进行特征化与标准化评估。结果表明,在污水处理阶段中由电力消耗和化学品消耗产生的污染物排放是造成污水处理阶段环境负荷的主要因素,而污泥处置阶段中由填埋和烟气排放所产生的污染物直接排放是造成环境影响的主要因素。(3)两种污泥处置工艺的对比结果表明,若污泥处置方法选用半干垃圾与污泥混烧工艺方法,分别会使现有污水处理系统的AP、EP、GWP、HTP和电能回收分别增加23.82倍,增加6.86倍,降低0.79倍,增加10.3倍,增加3.7倍。本论文将LCA与污水处理系统的环境影响评价相结合,完善了评价各工艺环境影响的技术方法,对今后国内污水处理系统节能减排工作具有一定指导意义。
[Abstract]:Sewage treatment is an industry with high pollution and high energy consumption, and its operation will cause great acidification effect and Greenhouse Effect problems, and environmental assessment can effectively analyze, predict and evaluate the possible environmental impact caused by the process used. The countermeasures and measures to prevent or mitigate the adverse environmental impact are put forward to achieve the goal of "saving energy, reducing consumption, reducing pollution and increasing efficiency". However, due to the lack of comprehensive evaluation of sewage treatment system in China at present, it is easy to be affected by subjective factors, which leads to the limitations of the environmental impact assessment method of sewage treatment system. In order to improve the evaluation method, this paper applies the life cycle evaluation (Life Cycle Assessment, LCA) theory to the environmental evaluation process of sewage treatment system, which is used to evaluate the environmental impact of different technological processes in sewage treatment system. Therefore, it can provide technical support for determining the key points of pollution control and energy saving and emission reduction in the future. (1) the impact assessment model of sewage treatment system is constructed by using life cycle evaluation method. Determine the study boundary range, trace the upstream section of the system, construct the life cycle list of the whole process, divide the sewage treatment system into sewage treatment stage, transport stage, Environmental impact assessment was carried out in sludge disposal stage. (2) four environmental impact indicators, including eutrophication potential, acidification potential, global warming potential, human toxicity potential, were used in the CML-Nov.2010 assessment model. The environmental impact within the boundary of sewage treatment system is characterized and standardized. The results show that the discharge of pollutants produced by electricity consumption and chemical consumption in sewage treatment stage is the main factor that causes the environmental load in sewage treatment stage. The direct discharge of pollutants produced by landfill and flue gas in sludge disposal stage is the main factor that causes environmental impact. (3) the comparison of the two sludge disposal processes shows that, If the sludge disposal method is mixed with semi-dry waste and sludge, the AP,EP,GWP,HTP and electric energy recovery of the existing sewage treatment system will increase 23.82 times, 6.86 times, 0.79 times, 10.3 times and 3.7 times respectively. In this paper, LCA is combined with the environmental impact assessment of sewage treatment system to perfect the technical method of evaluating the environmental impact of each process, which has certain guiding significance for the future work of energy saving and emission reduction of domestic sewage treatment system.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X703;X820.3

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