重金属Cr~(6+)在填埋场固化污泥阻滞层-土-水系统中迁移分析

为研究重金属Cr6+在填埋场固化污泥阻滞层及周边水土环境中的迁移,首先通过室内柔性壁实验得出了重金属Cr6+的水动力弥散参数,然后采用数值分析方法研究了重金属Cr6+在固化污泥阻滞层-土-水系统中100年内的迁移规律,指出在地层中设置固化污泥对于Cr6+离子的迁移有延迟阻滞作用。并对比分析了未设有阻滞层的情况,得到了重金属Cr6+历经10年、50年、60年和100年的迁移范围和浓度分布规律。

Analysis of transference character of heavy metal Cr6+ in solidified sludge-soil-water layers

To prevent the contamination of the pollutant leakage, the bottom of municipal solid waste landfill site is ordinarily liner layer. The solidified sludge can be a new kind of liner material by analysis. To make clear contaminants transportation in the blocking layer, the hydrodynamic dispersion parameters must be verified. It is impossible to obtain hydrodynamic dispersion parameters of sludge solidified layer with low permeability by the existing column tests and methods. To solve the problem, the breakthrough curve of Cr⁶⁺ as tipical representative is obtained by the improved flexible wall permeameter. Based on the breakthrough curve of Cr⁶⁺, the hydrodynamic dispersion parameters can be calculated by the derived formulas. And then, the parameters were used to analyze the transference of heavy metal Cr⁶⁺ in solidified sludge-soil-water layers. The time for transference was 100 years. Finite element method was used to simulate the transference circumstances. The concentration and distribution scopes were achieved in 10, 50, 60 and 100 years. Compared with it, the situation without solidified sludge layer was also analyzed. As shown in the results, the transference velocity is quicker, the concentration is higher and the distribution scope is larger under the same conditions. According to the experiment and numerical analysis, the solidified sludge layer has an important effect on postponing the transference of Cr⁶⁺.