垃圾卫生填埋结构对地质环境效应的控制研究

THE CONTROL OF REFUSE LANDFILL STRUCTURE ON GEOLOGICAL ENVIRONMENTAL EFFECT

通过大量的现场调查、室内外试验及综合分析，以多种手段较系统地研究了垃圾及其渗滤液成分组成与变化规律，填埋场的地理—地质条件，填埋结构单元的控制机理，填埋结构控制作用的数学模拟和垃圾卫生填埋结构优化设计系统及其应用。首先，根据实际调查资料的统计结果，论述垃圾成分受到生活水平、能耗结构、季节、地域等多种因素的影响，并分析垃圾产量和成分变化的一般规律。以试验和现场监测为基础，详细研究垃圾渗滤液成分的变化特征，探讨垃圾的分解过程，指出垃圾渗滤液成分具有以有机质及其分解产物为主的高浓度、强污染特性，总体上具有随时间呈负指数衰减的动态变化规律。结合成都长安垃圾填埋场，首次详细、系统地从试验和模型计算两方面研究填埋结构对地质环境效应的控制作用。控制作用体现在两个方面：一方面，是填埋结构的各个组成部分（衬里、垃圾层、填土层）能够有效地去除污染物质，由于填埋体类似于一个生物反应器，有机质发生生物降解，分解的终极产物（如ＮＨ＋４）可被填土层和衬里吸附；另一方面，通过改变衬里、填土层的厚度与密度，可以控制渗滤液在填埋体内的水动力条件，从而控制渗滤液下渗对地下水造成的污染。在试验结果的基础上，建立模拟模型，完整系统地研究渗滤液水头?

Sanitary landfill is main method of current municipal waste disposal around the world,which is about to be adopted widely in China.This kind of engineering’s success or failure is determined by its impact on the geological environment,and landfill structure is the direct condition controling geological environmental effect .Thus the study on the landfill structure for the control of geological environmental effect is not only characteristic of theory research,but also has the prospect of wide application.Therefore,this study has been supported by the National Natural Science Fundation of china. Based on a great number of field investigations and on-site or laboratory experiments,this study systematically analyzes the component and change tendency of rubbish and leachate,the geographical-geological conditions of landfill site,the control process of landfill structure units and their mathmatical simulation,as well as optimum design of landfill structure and its application by means of different methods. According to the investigation and statistic results,at first,the conclusion was drew that the component of rubbish is influenced by living level,energy consumption consitution,location and so on,and then tendency of production volume and composition of rubbish was analyzed.On the basis of experiments and on-site monitoring data,the changing tendency of leachate was also analyzed in detail as well as decomposition procedure of rubbish.The results show that leachate is mainly composed of organic matter,which is of higher concentration and stronger pollution,and components of leachate decay in form of negative exponent on the whole. Taking chang’an landfill site,Chengdu,as a sample,the control of landfill structure on the landfill geological environmental effect was analyzed in detail based on the experiments and mathmatical simulation calculation.The control includes two sides.On the one hand,the component of landfill structure(such as liner,rubbish layer,cover layer), could be able to effectively clean pollutants.Landfill body is similar to a biocreator in which organic matter are decomposed and products (such as NH + 4) are adsorbed by cover and liner soil.On the other hand,the thickness and density of liner and cover soil can also control the hydrodynamic condition of leachate in the landfill body,which influences the potential groundwater pollution caused by leachate.By means of mathmatical simulation based on the laboratory experiments,the assessment of compressive effect of leachate mound and basic parameters describing pollutants migration and transference was carreied out. Morover,the simulation model of rubbish sanitary landfill effect was built.The model can give results of unit,unit combination and complete simulation under certainty and uncertainty conditions.So the model increases quantitative understanding in the control of landfill structure and actual application value. Finally,a program of optimum design for rubbish sanitary landfill structure was developed,and its application to Chang’an landfill site,Chengdu,proves to be of great significance in practice.