北京市朝阳区沙子营垃圾污染物在潜水含水层中迁移规律的现场模拟实验

选择北京平原区水文地质、环境地质等方面都比较典型的沙子营垃圾堆放场,建立了其水文地质模型。在充分收集资料、分析得出部分计算所需参数后,采用现场弥散实验、勘查取样测试等方法,求得了该含水层的弥散系数等参数;用二维非稳定流溶质运移方程对污染物在此含水层中的迁移扩散规律、速度和污染范围等进行了模拟计算;采用现场钻探、取样测试分析等方法,评价了该含水层的实际污染状况。实验模拟计算和现场调查结果表明:污染物在潜水含水层中的运移规律遵循二维非稳定流场中的溶质运移方程,污染物在潜水含水层中的运移速度约为86.25m/a,迁移扩散主要发生在地下水流向上,侧向扩散宽度极小,是地下水流向上的1/17。

In-situ modeling experiments on the transport of pollutants from the Shaziying garbage dump field in an aquifer in the Chaoyang District, Beijing, China

The water quality of shallow aquifers that have direct relationships to human heath and ecological safety has been seriously threatened by the widespread dumps of industrial solid waste and urban and rural garbage. The authors chose a garbage dump field with typical hydrogeological and environmental-geological characteristics in the Beijing plain to construct a hydrogeological model. Then after part of parameters for calculations were obtained using the collected data, they found the parameters such as the dispersion coefficient of the aquifer by performing in-situ dispersion experiments and conducting investigations and sample tests; the equation of solute transport in 2D unsteady flow was used for modeling and calculation of the processes and rates of transport/diffusion and pollution scope of garbage pollutants in the aquifer. In addition, in-situ drilling and sample analysis were carried out to evaluate the actual pollution situation in the aquifer. The modeling experiments and in-situ investigations show that: the transport/diffusion processes of pollutants in the aquifer follow the equation of solute migration in the 2D unsteady flow field; the rate of migration of pollutants in the aquifer is about 86.25 m/a; the pollutant migration and diffusion mainly occur in the upward groundwater flow; and the width of the lateral groundwater diffusion is very small, being 1/17 of the upward groundwater flow.