【作者】 唐然；

【导师】 龙腾锐；

【作者基本信息】 重庆大学 ， 市政工程， 2008， 博士

【摘要】 污水处理是涉及技术、经济、环境与社会诸因素的复杂过程。在污水处理工艺优选决策过程中,采用成本效益分析等单目标决策方法有失偏颇。然而,目前污水处理工艺多目标决策模型存在着决策指标体系差别较大、决策指标的量化手段过于主观、决策指标权值求解运算过程稳定性差以及决策模型没有充分体现污水处理工艺优选决策过程的数学特性等问题,致使尚没有被普遍接受的工艺优选决策模型。该文是建设部荷兰赠款项目《中国西部小城镇环境基础设施技术指南》编制课题(项目编号:MOC-NGGP-2003-3)的部分研究内容,着重研究在备选工艺确定的条件下如何系统、全面、客观与科学地对城镇污水处理工艺进行优选决策。包括城镇污水处理设施适宜工艺的探讨、可持续污水处理工艺决策指标体系及其量化方法的研究、污水处理工艺决策指标权值确定方法的研究、污水处理工艺决策模型的研究以及备选工艺决策指标灵敏度分析的探讨5个方面。主要研究内容如下:①实地调研与文献调研表明,我国规划建设的西部城镇的污水处理量在5×104m3/d以下,多在(0.2~2.0)×104m3/d范围内,大部分西部城镇污水为典型生活污水。对于我国小城镇污水处理设施,推荐采用SBR系列、氧化沟系列、以及生物滤池系统,土地资源比较丰富的城镇可采用自然净化系统。②分别剖析了以费用最小与“绿色性”作为污水处理工艺优选决策目标存在的不足,认为用可持续性作为污水处理工艺优选决策目标更符合污水处理工艺的发展方向。借鉴以往研究者的研究成果,提出污水处理工艺的可持续性包括技术可持续、经济可持续、环境可持续与社会可持续四个方面。根据我国有关基础研究缺乏的现状,从技术、环境、经济与社会四个方面构建了客观、全面且操作性较强的可持续决策指标体系,并确定了决策指标的量化方法。该体系包括技术、能量利用率、间接能耗、占地、年费用、运行管理难易程度与对操作者文化水平要求七个决策指标。应用研究表明,污水处理工艺可持续决策指标较传统技术经济指标更全面,指标的量化方法可操作性较强。③创建了基于模糊聚类的改进遗传算法(FMGA)来确定决策指标的权值。较常规权值求解方法,FMGA不仅能最大程度的保留判断者的原始决策信息,在一定范围内自动调整判断矩阵的一致性,而且能稳定、快速且有效地求得决策指标权值。通过大量数值仿真试验对FMGA的5个控制参数的取值范围进行了探讨。仿真试验表明:变量x m二进制编码的长度l由解变量的取值范围与精度要求共同确定;群体规模N宜等于或大于300, A为5% N ~30% N ;采用聚类水平λ将种群尽量划分为个体数目相等的两类;变异概率为验证FMGA性能,利用Delphi语言仿真算法,将FMGA与基本遗传算法(简称CGA)进行对比研究。结果表明,FMGA较CGA更能有效克服早熟收敛,能在较短时间内逼近全局最优解;运算结果较CGA提高4个数量级,且运算过程不存在震荡现象。④通过发放调查表获得专家原始判断矩阵;采用FMGA计算得到三峡库区城镇污水处理工艺优选决策指标权值,其重要性排序为:经济(0.2365)>技术(0.2094)>物耗(0.1640)>O&M难易程度(0.1544)>文化水平要求(0.1383)>能耗(0.1014)。该结果表明,在当前情况下经济与技术为三峡库区污水处理工艺优选决策中最重要的指标。⑤根据城镇污水处理工艺优选决策的模糊性、灰色性与决策指标间相互补偿的数学特征,将半梯形分布的隶属函数与灰色关联法相结合,创建了模糊—灰色关联法,并将其用于构建城镇污水处理工艺优选决策模型。模糊—灰色关联法能充分体现污水处理工艺优选决策过程的数学特征。将模糊-灰色关联法与灰色关联法、模糊数学法与逼近理想解法进行比较研究,结果表明,模糊-灰色关联法的决策结果更为科学合理,且运算过程简洁,运算量小。⑥推导得出了模糊-灰色关联法灵敏度分析的结论,包括备选方案排序不变与排序改变两种情况下,决策指标值的允许变动范围。该方法的灵敏度分析能为研究人员、设计人员、污水处理厂运行与管理人员提供改进或改善污水处理工艺的参考信息。⑦针对三峡库区某设计处理规模为4000m3/d的城镇污水处理厂,按SBR、BAF与Orbal氧化沟3种备选工艺进行了决策分析。决策结果表明,BAF工艺最优,SBR工艺次之,Orbal氧化沟工艺相对较劣。灵敏度分析表明,对西部小城镇污水处理设施(设计处理规模为4000m3/d左右),BAF工艺与SBR工艺明显优于Orbal氧化沟。对于西部小城镇污水处理厂,重视运行中的节能减耗工作,并提高处理厂职工的操作与运行水平,可使污水处理过程更符合可持续的发展要求。更多还原

【Abstract】 Wastewater treatment is a complex process related to many issues, including technique, economy, environment and society. It is unreasonable to use single objective optimization model, such as cost-benefit analysis method, to select the optimal wastewater treatment alternative. However, there were many problems of existing multi-objective optimization models of wastewater treatment alternatives selection, such as, the large difference between decision indicator systems, and the too subjective qualification methods of decision indicator, and the unstable calculating process of indicator-weight, and the optimization models not well matched to mathematic characteristics of the alternatives selection. Therefore, there was still not a generally accepted optimization model of the wastewater treatment alternatives selection.The dissertation was a part of the Netherlands Government’s Grant Project Technical manual for environmental infrastructure in China’s western small cities (the project number is MOC-NGGP-2003-3), which aimed at how to systemically, objectively and scientifically select alternatives for the WWTP of western small cities. In the dissertation, the appropriate alternatives for small towns and cities wastewater treatment were discussed, the sustainable decision indicators and their qualification methods were presented, and the way to stably and effectively calculate indicator- weight was studied. Furthermore, a new multi–criteria decision method and its sensitive analysis for optimal wastewater treatment alternatives selection were set up. The main research contents are as follows:①By field survey and literature review, it was concluded that the wastewater flux of towns or small cities was below 5×104m3/d in western China, and mostly fell into the range of (0.2~2.0)×104m3/d. Moreover, the domestic wastewater was the main component of wastewater in western small cities. For the WWTP of small cities, SBR series, Oxidation Ditch series and biofilter series were recommended, and nature treatment systems were suggested to the region abundant with land resource.②There were some shortcomings for the minuum cost and‘greeness’respectively as the decision targets of optimal wastewater treatment alternatives selection, so sustainability was suggested as the decision object of optimal wastewater treatment alternatives selection. Referred to the researchs of some researchers, it was presented that the sustainability of wastewater treatment alternatives could be discribed by technique sustainability, economy sustainability, environment sustainability and society sustainability. Based on the situation of basic research data in China, the objective , reasonable and operational decision indicator systems was set up, which included technique, efficiency of energy utilization, indirect energy consumption , land occupation, annual expense, O&M,professional skill reqirement. Furthermore, the qualification methods of decision indicators were also presented. The case study showed that the sustainable decision indicators were more thorough and reasonable than economic indicator used by cost–benefit analysis method, and the qualification methods of decision indicators were easy to apply.③The Modified Genetic Algorithm based on Fuzzy System was established (FMGA) to determine the weights of decision indicators. Compared with other tranditional weight calculation methods, FMGA not only could keep the original decision information as more as possible and automatically modify the consistency of judgment matrix, but also could stably, quickly and effectively calculate the weights of decision indicators.And the scale of five parameters of FMGA was discussed by simulation test. The reslts showed that the number bits of variables’ binary code was depend on the precision reqirement , the size of population N should equal to or more than 300 and the number of elitist indivadual A could be between 5 percent and 30 percent of N . Cluster level should divided N into two parts with the same scale, mutation probability p m equaled to O (L N1).FMGA and Canonical Genetic Algorithm (CGA) were compared in order to verify the advantage of FMGA. The compared results showed that FMGA could more effectively avoid premature convergence and get global optimal than CGA.④The decision indicator weights of wastewater treatment alternatives selection in Three Gorges Reservoir Region Areas were studied. In result, the rank in desending order of importance of decision indicators were, annual expense (0.2365)>technique(0.2094)>land occupation(0.1640)> O&M(0.1544)>professional skill reqiremnet (0.1383)>energy consumption(0.1014),which showed annual expense and technique were two most important decision indicators at present.⑤According to the math characteristics of wastewater treatment alternatives selection, which was fuzziness, greyness and dependency of decision indicators, the membership function was combined with grey relational analysis to construct fuzzy-grey relational analysis method. Fuzzy-grey relational analysis method was applied to multi-objective decision model of optimal wastewater treatment alternatives selection, which well reflected math character of wastewater treatment alternatives selection. The case study indicated that, fuzzy-grey relational analysis method was more reasonable and easy to operate compared with grey relational analysis method, fuzzy algorithm and TOPSIS.⑥Sensitive analysis of fuzzy-grey relational analysis method was studied. By the sensitivity analysis, the range of decision indicators could be received, in the case that the rank of alternatives be changed or kept. The study showed that sensitive analysis of fuzzy-grey relational analysis method could offer some information about improving the process for researchers, designers and managers.⑦SBR, BAF and Orbal Oxidation ditch were compared for the western small city wastewater treatment plant with capacity of 4000m3/d. The result of Fuzzy-grey relational analysis showed that BAF was the best alternative, and SBR was better than Orbal Oxidation ditch. Furthermore sensitive analysis showed that BAF and SBR were better than Orbal Oxidation ditch. For western small city wastewater treatment, the treatment process could better match with sustainability by reducing energy and material consumption, and improving professional skill level of panel.更多还原