渗滤液中氯代烃在土壤包气带的迁移行为研究

发布时间：2018-04-26 13:17

本文选题：渗滤液 + 五氧联苯　；参考：《西南交通大学》2015年硕士论文

【摘要】：氯代烃是一类对人体健康和环境安全危害性很大的有机污染物。随着工业化进程的加快,人类生产生活垃圾中含氯代烃的废弃物不断增多,导致垃圾渗滤液中氯代烃的含量越来越大。在一些防渗措施简单或没有防渗措施的简易垃圾堆场,由于垃圾渗滤液不断渗漏,将会造成该区域土壤和地下水环境的氯代烃污染。本文以成都某简易垃圾堆场为研究对象,通过对该区域土壤包气带组成和堆场垃圾渗滤液性质的研究,选取其渗滤液中六氯苯和五氯联苯两种氯代烃为特征污染物,并通过室内土柱动态吸附实验和弥散实验分别确定了上述两种污染物的在该区域包气带的吸附分配系数Kd和包气带的垂直弥散系数Dzz,建立五氯联苯和六氯苯在该区域包气带中迁移的数学模型,运用Hydrus-1D软件进行模拟,并预测五氯联苯和六氯苯穿透该区域土壤包气带进入地下水环境所需要的时间。室内土柱动态吸附实验结果表明：五氯联苯和六氯苯在该简易垃圾堆场区域土壤包气带的等温吸附符合线性吸附模式；五氯联苯在该区域土壤包气带中的分配系数Kd1=0.097L/g,六氯苯在该区域土壤包气带中的分配系数Kd2=0.137L/g;Kd1Kd2,六氯苯比五氯联苯更易受该区域包气带吸附作用影响,被长时间滞留在包气带中,而五氯联苯较之比六氯苯的迁移能力更强,更容易穿过包气带,污染地下水环境；该区域土壤包气带对五氯联苯的最大吸附量Sm1=6319mg/g,而对六氯苯的最大吸附量Sm2=17182mg/g,后者约为前者的三倍,说明该简易垃圾堆场区域单位质量包气带土样对六氯苯具更好的吸附能力；Hydrus-1D软件模拟结果表明：相同时间条件下,渗滤液中六氯苯和五氯联苯的浓度随着包气带深度的增加而不断减小,说明包气带能吸附滞留这两种典型氯代烃,对两者向下迁移的过程具延迟作用,包气带越厚渗滤液中六氯苯和五氯联苯穿透包气带所需的时间也越长；相同深度下,随着时间的增加,渗滤液中六氯苯和五氯联苯的浓度不断增加,并逐渐达到其初始浓度,说明包气带对两者的吸附达到饱和；六氯苯和五氯联苯分别需要约1670d、2505d穿透该区域土壤包气带,进入地下水层,同时,在10000d时该区域土壤包气带对六氯苯和五氯联苯基本达到吸附饱和,六氯苯和五氯联苯的垂向迁移不再受到包气带吸附作用影响,两者将以初始浓度进入地下水层,污染地下水环境。本研究有助于合理确定从地表经包气带衰减后进入含水层的污染源强,可为垃圾堆场土壤和地下水有机污染防治提供理论依据。
[Abstract]:In this paper , the adsorption distribution coefficient Kd and the vertical dispersion coefficient Dzz of the landfill leachate in the landfill leachate were determined by dynamic adsorption experiments and dispersion experiments of the landfill leachate . The results showed that the isothermal adsorption of PCP and HCB in the landfill gas zone met the linear adsorption mode .
The distribution coefficient Kd1 = 0.097L / g , Kd1Kd2 = 0.137L / g ; Kd1Kd2 , HCB and Pentachlorobiphenyl are more susceptible to the adsorption of the gas in the region .
The maximum adsorption capacity ( Sm1 = 6319 mg / g ) of Pentachlorodiphenyl and the maximum adsorption capacity ( Sm2 = 17182mg / g ) of HCB were about three times that of the former .
The simulation results show that the concentration of HCB and Pentachlorobiphenyl in the leachate decreases with the increase of the depth of the bag with the same time .
Under the same depth , with the increase of time , the concentration of HCB and PCA in leachate is increasing , and its initial concentration is gradually reached .
The results of this study are helpful to reasonably determine the strong pollution from the surface to the aquifer and provide a theoretical basis for the prevention and control of soil and groundwater organic pollution .

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X523

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