【作者】 李小芳；

【导师】 孙宝盛；

【作者基本信息】 天津大学 ， 环境工程， 2012， 硕士

【摘要】 城市污水排放量和化学需氧量（COD）排放量的预测工作十分重要，本文在了解城市污水排放量和污染物总量控制的研究进展的基础上，分析常规模型在预测中所存在的问题，建立了一种改进的灰色马尔可夫模型，然后将其应用到城市污水排放量和COD排放量的预测中。在灰色模型、马尔可夫模型的基础上，针对传统灰色马尔可夫模型的优缺点，本文建立了一种改进的灰色马尔可夫模型。改进的灰色马尔可夫模型是通过对马尔可夫预测结果进行优化来提高预测结果的准确度，它的实质是在充分考虑各种状态的基础上加大了高概率状态的权重。改进的模型既具有灰色马尔可夫模型建模数据少、计算方法简单、适用于随机波动的数据处理等特点，又能避免单个灰色马尔可夫模型可能出现的最差预测结果。根据2001年到2009年的天津市城市污水排放量数据，应用本文建立的改进灰色马尔可夫模型进行预测。结果表明：改进的灰色马尔可夫模型的预测精度远高于灰色模型，且能避免传统灰色马尔可夫预测结果的最差情况；根据改进的模型预测结果，到2015年，天津市生活污水排放量达到65412.41万吨，工业废水排放量为18707.69万吨，城市污水排放总量为84120.10万吨，生活污水排放量在城市污水排放总量中的比例为77.76%。根据2001年到2009年天津市COD排放总量的数据，应用本文建立的改进灰色马尔可夫模型进行预测。结果表明：改进的灰色马尔可夫模型与传统的灰色马尔可夫模型预测结果一致，都有较高的预测精度；2010年到2015年间，天津市COD排放总量大致呈指数减小趋势，于2015年达到11.04万吨，可以实现天津市“十二五”规划中削减COD排放总量的目标。在“十一五”期间，天津市生活污水中COD排放量呈缓慢增长趋势，工业废水中COD排放量呈逐年减小趋势，城市污水中COD排放量呈现缓慢减小趋势，它们在2010年的数值较2005年分别减小了-2.28万吨、3.69万吨和1.41万吨，因此“十一五”期间天津市COD减排工作主要依靠工业减排来实现。更多还原

【Abstract】 The forecast work of urban wastewater discharge and chemical oxygen demandemission was important. Based the investigation on research progress of urbanwastewater discharge and pollution gross control, this paper analysed thedisadvantages of conventional model and established a modified Gray Markov Modelwhich then applied to the forecast work of urban wastewate discharge and chemicaloxygen demand emission.After analysing the advantages and disadvantages of traditional Gray MarkovModel based the Gray Model and Markov Model knowledge, this paper established amodified Gray Markov Model. The modified model had high accuacy as it optimizedthe Markov process, it incresed the weight of high probable state considering allpossible states. The modified Gray Markov Model had following characteristics:needing less data, having simple calculation process, improving the simulationaccuracy for data sequences with great random fluctuation and can avoid the worstresult obttained by conventional Gray Markov Model.Based the domestic sewage discharge and industrial wastewater discharge inTianjin from2001to2009, modified Gray Markov Models were established toforecast them respectively. The results showed that: the forecast results of modifiedGray Markov Model had higher accuracy than Gray Model, and the modified Modelcould avoid the worst results of conventional Model. In the period from2010to2015,the domestic sewage discharge had an increase trend and would be654.1241milliontons in2015, the industrial wastewater discharge had a decreased trend and would be187.0769million tons in2015, the urban wastewater dischage had an increased trendand would be841.2010million tons in2015, the percentage of domestic sewagecharge in urban wastewater discharge had an increased trend as time went on andwould be77.76%in2015.According to the chemical oxygen demand emission of domestic sewage andindustrial wastewater in Tianjin from2001to2009, modified Gray Markov Modelwas established to forecast the total chemical oxygen demand emission. The resultsshowed that forecast value of modified Model was the same with the conventionalGray Markov Model and had high accuracy. In the period from2010to2015, the totalchemical oxygen demand emission had a decreased trend and would be110.4 thousand tons in2015, so it could reach the goal of reducing chemical oxygendemand emission in the “12th of five-year plan” of Tianjin. During the period of“11th of five-year plan” in Tianjin, the domeistic chemical oxygen demand emissionhad an inceased trend and the value would be increased by22.8thousand tonscmpared with the year2005, the industrial chemical oxygen had a decreased trend andthe value would be reduced by36.9thousand tons cmpared with the year2005, thetotal chemical oxygen demand emission had a decresed trend and the value would bereduced by14.1thousand tons cmpared with the year2005, so the reducing work ofchemical oxygen demand total emission depended mainly on industry.更多还原