对城市垃圾填埋场渗滤液及其污染特性进行了分析,对我国城市垃圾填埋造成的土地、地下水污染现状进行了3个实例分析。通过实验室模拟实验研究渗滤液中污染物在地下环境中迁移转化作用,实验结果表明,垃圾渗滤液在地下出现了4个顺序氧化还原带,分别为产甲烷带、Fe(Ⅲ)还原带、NO3^-还原带和氧还原带,微生物在每个带利用的最终电子受体是不同的。最后以北天堂垃圾填埋场为例,建立地下水污染物运移的数值模型,对垃圾渗滤液污染的控制方案进行了模拟研究,模拟计算表明,北天堂垃圾填埋场顶部防护层的设置,必须使外部水进入垃圾场的入渗量控制在小于36mm/a,才能有效控制渗滤液的污染。
The characteristic of landfill leachate and pollution have been considered first in this paper, 3 land and groundwater pollution cases by landfill are introduced and discussed. Then laboratory simulation has been done for studying the underground migration of leachate pollutants. Experimental results indicate that four sequent redox zones are appeared in pollution plume, i. e. methanogenic zone, iron reduction zone, nitrate reduction zone and oxygen reduction zone. The terminal electron acceptors used by microbes in different zones are different (they are CO2, Fe(Ⅲ), NO;- and Oz correspondingly). Finally, the Beitiantang landfill site has been considered as a typical site for case study. The numerical model has been built for simulation of the underground pollutants. Different leachate containment measures have been proposed and simulated with the model. The results indicate that the infiltration quantity of outside water must be controlled below 36 mm/a so that the groundwater near the landfill site can be protected from pollution.