Kambhu Ann, Li Yusong, Gilmore Troy, Comfort Steve
Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0856, USA; Department of Environmental Technology and Management, Kasetsart University, Bangkok, 10900, Thailand.
Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0856, USA.
J Hazard Mater. 2021 Feb 5;403:123719. doi: 10.1016/j.jhazmat.2020.123719. Epub 2020 Aug 20.
Aerated, slow-release oxidants are a relatively new technology for treating contaminated aquifers. A critical need for advancing this technology is developing a reliable method for predicting the radius of influence (ROI) around each drive point. In this work, we report a series of laboratory flow tank experiments and numerical modeling efforts designed to predict the release and spreading of permanganate from aerated oxidant candles (oxidant-wax composites). To mimic the design of the oxidant delivery system used in the field, a double screen was used in a series of flow tank experiments where the oxidant was placed inside the inner screen and air was bubbled upward in the gap between the screens. This airflow pattern creates an airlift pump that causes water and oxidant to be dispersed from the top of the outer screen and drawn in at the bottom. Using this design, we observed that permanganate spreading and ROI increased with aeration and decreased with advection. A coupled bubble flow and transport model was able to successfully reproduce observed results by mimicking the upward shape and spreading of permanganate under various aeration and advection rates.
曝气缓释氧化剂是一种用于处理受污染含水层的相对较新的技术。推进这项技术的一个关键需求是开发一种可靠的方法来预测每个驱动点周围的影响半径（ROI）。在这项工作中，我们报告了一系列实验室流动槽实验和数值模拟工作，旨在预测曝气氧化剂蜡烛（氧化剂 - 蜡复合材料）中高锰酸盐的释放和扩散。为了模拟现场使用的氧化剂输送系统的设计，在一系列流动槽实验中使用了双层筛网，其中氧化剂放置在内层筛网内，空气在筛网之间的间隙中向上鼓泡。这种气流模式形成了一个气举泵，导致水和氧化剂从外层筛网顶部分散并在底部被吸入。使用这种设计，我们观察到高锰酸盐的扩散和影响半径随着曝气增加而增大，随着平流减小。一个耦合气泡流和传输模型通过模拟在各种曝气和平流速率下高锰酸盐的向上形状和扩散，能够成功再现观察结果。
