Contaminant migration and the retention behavior of a laterite-bentonite mixture engineered barrier in a landfill
Contaminant migration and the retention behavior of a laterite-bentonite mixture engineered barrier in a landfill
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DOI：
10.1016/j.jenvman.2021.114338
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发表时间：
2021-12-22
影响因子：
8.7
通讯作者：
Zhang, Ke-neng
中科院分区：
文献类型：
--
作者：
He, Yong;Hu, Guang;Zhang, Ke-neng
近年来，地下水污染日益严重，特别是垃圾填埋场渗滤液渗漏。在这项研究中，通过基于实验室和现场测试结果的数值模拟，分析了垃圾填埋场中 Cu2} 的迁移以及压实红土膨润土工程屏障系统对污染物的保留行为。结果表明，随着膨润土配比的增加，红土-膨润土混合物的导水率降低：当膨润土配比减少时，红土-膨润土混合物的导水率分别为4.718×10-7、2.103×10-7、7.899×10-8、3.918×10-8和1.614×10-8 cm/s。分别为 0%、2%、5%、10% 和 20%。在去离子水和浓度为0.01和0.1 mol/L的CuSO4溶液浸润下，红土和膨润土配比为2%的混合物的导水率逐渐降低。这可能是由于随着溶液浓度的增加，红土的絮凝程度增加。数值模拟结果表明，3650天后Cu2}的迁移范围约为1500 m。 0.5 m 工程屏障对 Cu2} 的保留效率为 67%。然而，当工程屏障厚度增加到 1.0 m 时，保留效率超过 83%。实验室测试和数值模拟结果表明，压实红土-膨润土工程屏障体系对Cu2}具有良好的截留效果。这些观测结果可为垃圾填埋场地下水污染的防治提供有效的思路。
Groundwater pollution has become increasingly severe in recent years, particularly owing to leachate leakage in landfills. In this study, the migration of Cu2} in a landfill and the retention behavior of a compacted lateritebentonite engineered barrier system toward the contaminant were analyzed by a numerical simulation based on laboratory and field test results. The results show that the hydraulic conductivity of the laterite-bentonite mixture decreased with an increase in the bentonite ratio: The hydraulic conductivities of the laterite-bentonite mixture were 4.718 x 10-7, 2.103 x 10-7, 7.899 x 10-8, 3.918 x 10-8, and 1.614 x 10-8 cm/s when the bentonite ratios were 0, 2%, 5%, 10%, and 20%, respectively. The hydraulic conductivity of laterite and of the mixture with a bentonite ratio of 2% decreased gradually under infiltration of deionized water and CuSO4 solutions with concentrations of 0.01 and 0.1 mol/L. This could be attributed to the increased degree of flocculation of laterite with the increase in the solution concentration. The results of the numerical simulation indicate that the migration range of Cu2} after 3650 days was approximately 1500 m. The retention efficiency of a 0.5 m engineered barrier for Cu2} was 67%. However, the retention efficiency exceeded 83% when the engineered barrier thickness was increased to 1.0 m. The results of the laboratory tests and numerical simulation demonstrate that a compacted laterite-bentonite engineered barrier system has a good retention effect on Cu2}. These observations may provide effective concepts for the prevention and control of groundwater pollution in landfills.