【作者】 刘辉；

【导师】 黄涛；

【作者基本信息】 西南交通大学 ， 市政工程， 2010， 博士

【摘要】 填埋法处理城市生活垃圾会产生大量污染物浓度高、持续时间长、流量极不均匀且水质变化大的渗滤液。而这些渗滤液如不加处理则很有可能成为地下水污染的一个源头,对周围环境产生二次污染。为了尽量减少渗滤液对地下水的污染,就必须确定产生的水量,并对渗滤液水质进行预测,才能采取相应的工程措施,收集和处理渗滤液。控制和治理垃圾渗滤液需要对垃圾渗滤液的产生和运移规律进行研究,而垃圾填埋体渗透系数作为垃圾渗滤液产生、运移研究的基本参数,其变化规律对垃圾渗滤液产生和运移的研究有着非常重要的影响。论文通过资料收集、理论分析的方法,确定了影响城市生活垃圾填埋体渗透性能的主要影响因素,在此基础上通过室内物理模拟城市生活垃圾填埋体温度变化、垃圾降解规律、主压缩沉降阶段城市生活垃圾填埋体渗透性能变化规律,建立了城市生活垃圾填埋体渗透性能数学模型。通过国内外文献查阅和理论分析,对垃圾本身的物理性质和填埋作业中垃圾所处的不同环境对城市生活垃圾填埋体渗透性能的影响进行分析判断,选取垃圾密度、填埋高度、有效压力、垃圾沉降、垃圾成分等因素作为分析论证的重点,经过理论分析认为城市生活垃圾填埋体渗透性能的变化是由于垃圾填埋体本身骨架的变化引起,它反映在宏观现象上就是垃圾填埋体的沉降,而垃圾沉降主要与垃圾的填埋深度和垃圾中有机成分的降解有关。因此影响城市生活垃圾体渗透性能变化的主要因素是垃圾填埋深度与垃圾有机成分降解率。选取29、33、37、41、45℃作为室内物理模拟城市生活垃圾填埋体降解率试验研究的参数值,通过对城市生活垃圾填埋体渗滤液pH值、COD、NH3-N浓度和填埋气体中CH4浓度的试验,判断垃圾在降解过程中所处的阶段,并通过碳原子守恒对城市生活垃圾降解率进行计算,通过对城市生活垃圾降解律计算数据进行统计分析认为,单—温度下城市生活垃圾降解律变化规律随时间大致符合生长曲线,41℃与45℃城市生活垃圾降解速度最快,城市生活垃圾降解率相差不大,可以认为当温度大于41℃,城市生活垃圾降解律可以按照41℃时降解律计算。选取成都市长安垃圾卫生填埋场新鲜垃圾进行室内温度变化物理模拟,监测了垃圾柱温度、渗滤液COD、氨氮、CH4浓度变化情况,按照城市生活垃圾降解过程,将整个试验过程划分为好氧分解阶段、厌氧分解产酸阶段和厌氧分解产甲烷阶段三个阶段。总体上垃圾温度变化经历先升高后降低的变化过程,在好氧分解阶段垃圾温度上升较快,大部分时间温度始终保持上升状态。在厌氧分解的产酸阶段,垃圾温度会出现变化的反复性,垃圾温度的最高值将会产生在厌氧分解的产酸阶段的前半部分。而在厌氧分解产甲烷阶段垃圾温度将保持持续下降的状态。将城市生活垃圾渗透性能变化划分为两个阶段—主压缩沉降阶段和次压缩沉降阶段,在这两个阶段内影响垃圾填埋体渗透性能的主要因素分别为垃圾填埋高度和垃圾降解率。选取处于4种压力状况下的城市生活垃圾填埋体,对其主压缩沉降阶段渗透性能进行室内物理试验,试验中4种压力状况下垃圾填埋体试验测定分析符合达西定律,其COD变化处于产酸阶段,对渗透性能的影响可以不予考虑；对垃圾渗透系数计算表明,处于主压缩沉降阶段内,除没有施加压力状况下垃圾填埋体渗透性能变化规律与其他试验表现不尽相同外,其他垃圾填埋体渗透系数变化大致符合自然指数规律；在假设垃圾填埋体渗透性能在同一水平方向上基本不变的基础上,可以认为垃圾填埋体渗透性能在垂直方向上服从自然指数变化规律；根据两个阶段内主要因素对垃圾渗透性能的贡献量的大小,建立了城市生活垃圾渗透性能变化规律数学模型。更多还原

【Abstract】 Landfill method will generate large amount of leachate with high concentration of pollutant, long duration and uneven flow and water quality change. Whereas this sort of leachate, if not treat properly, will become the source of underground water contamination, causing secondary pollution. In order to reduce the contamination of underground water, water amount and quality should be predicted to select the engineering measures of leachate collection and treatment. Research on the regulation of leachate production and migration is necessary for controlling and disposing the leachate. While as the essential parameter for leachate production and migration, the permeability coefficient has a great impact on the study of production and migration.This dissertation uses the methods of data collection, theoretical analysis to determine the main impact of municipal solid waste landfill body permeability. Based on this, through the indoor physical simulation temperature change of MSW landfill body, waste degradation discipline, the change law of municipal solid waste landfill body permeability in the main compression settlement stage, a mathematical model of municipal solid waste landfill body permeability is built.By searching domestic and foreign literature and theoretical analysis, analysis were carried out on the impact the refuse physical nature and landfill operations in different environments on landfill body permeability, selecting waste density, landfill height, effective pressure, waste deposition, waste composition and other factors as the key point for analyzing and demonstration. By theoretical analysis, it can be considered that the permeability MSW landfill body change is mainly due to their skeleton, which could be observed as settlement when reflected in the macro-phenomena, whereas the settlement is closely related to landfill depth and biodegradation of the organic components. Therefore the main factors on the permeability are the landfill depth and biodegradation rate of organic ingredients.Select 29,33,37,41,45℃as the parameter values for the degradation rate experiments of the indoor physical simulation of municipal solid waste landfill body. By researching pH value, COD, NH3-N concentration in the leachate and CH4 concentration in the landfill gas, determine the stage of the refuse stated. And then use carbon atoms conservation to calculate the degradation rate of the MSW. After statistical analysis of the calculation data of MSW degradation rate, it concluded that degradation rate accord with growth curve in single temperature, and degraded the fastest at 41℃and 45℃, showing similar the degradation rate. When temperature is over 41℃, the degradation rate could be calculated according to that in 41℃.This study collected newly dumped refuses from Changan Landfill to set up indoor physical simulation column experiments on temperature variation, in which the temperature of refuse column, COD of leachate, NHx-N and concentration of CH4 were monitored. According to the refuse degradation processing, the whole experiment was divided into aerobic degradation stage, acidogenic stage of anaerobic degradation and methanogenic stage of anaerobic degradation). Temperature in refuse columns increased first and then decreased as a whole. Temperature increased drastically at aerobic degradation stage. During the acidogenic stage of anaerobic degradation, temperature changed repeatedly because of small amount of heat was released by anaerobic process, and the maximum temperature occurred at the first part of acidogenic stage of anaerobic degradation. While in the methanogenic stage of anaerobic degradation, the temperature kept decreasing.The variation of landfill’s permeability could be divided into two stages:the main compression settlement stage and the second compression settlement stage. The main impact factors of these two stages were landfill height and refuse degradation rate, respectively. In lab simulation, landfills under four different pressure conditions were chosen to analyze the permeability characteristics during main compression settlement stage. It was shown that permeability analysis results under four pressures were consistent with Darcy’s law and COD variation happened in acidogenic phase, whose influence could be ignored. With the exception of the experiment under no external pressure, the permeability characteristics in other landfill simulations during the main compression settlement stage were roughly following the natural exponential law. Under the assumption that permeability of landfill’s body is kept essentially constant in horizontal direction, it can be assumed that the change of permeability conform to natural exponents in vertical direction; Based on the main factors’contributions to permeability in the two stages, the mathematical models of MSW permeability are established.更多还原