Tsuchida Kyouhei, Nakamura Kengo, Watanabe Noriaki, Komai Takeshi
Graduate School of Environmental Studies, Tohoku University 6-6-20 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan.
Heliyon. 2022 Nov 10;8(11):e11541. doi: 10.1016/j.heliyon.2022.e11541. eCollection 2022 Nov.
The influence of flow channels on the leaching behavior of toxic elements in contaminated soil cannot be neglected in a column percolation test. This study presents a visualization of the flow channel formed in the soil and evaluated the relationship between the leaching behavior of soil components and flow. We conducted column percolation tests with two types of filling methods (Compaction and No compaction) and used X-ray computed tomography to visualize the soil structure and non-uniform flow. Additionally, the variations of flow in a cross section of water were evaluated using hydraulic conductivity based on differential pressure. Under No compaction, a flow occurred throughout the soil column at the beginning of the water passage, but a non-uniform flow emerged as the liquid-solid ratio increased; under Compaction, a non-uniform flow was formed from the beginning of water passage. The leaching behavior of the major components and toxic elements from soil with high adsorptive properties was significantly affected by the filling method up to a liquid-solid ratio of 2. These results suggest that the non-uniform flow formed in the column percolation test has a significant impact on the leaching of soil components.
在柱体渗滤试验中，流道对污染土壤中有毒元素淋溶行为的影响不容忽视。本研究展示了土壤中形成的流道的可视化情况，并评估了土壤组分淋溶行为与水流之间的关系。我们采用两种填充方法（压实和未压实）进行柱体渗滤试验，并利用X射线计算机断层扫描技术对土壤结构和非均匀流进行可视化。此外，基于压差利用水力传导率评估了过水断面水流的变化情况。在未压实条件下，通水开始时整个土柱内均有水流，但随着液固比增加出现了非均匀流；在压实条件下，通水一开始就形成了非均匀流。在液固比达到2之前，填充方法对具有高吸附性的土壤中主要组分和有毒元素的淋溶行为有显著影响。这些结果表明，柱体渗滤试验中形成的非均匀流对土壤组分的淋溶有重大影响。
