Collaborative Research: Innovative Injection and Extraction Schemes to Enhance Mixing in Aquifers for Improved In Situ Remediation

受污染地下水的就地修复往往需要将处理溶液引入含水层，以促进污染物降解反应。就地修复的一个重大挑战是在多孔介质中混合的固有困难。如果不充分混合处理溶液和受污染的地下水，就不可能发生实现就地修复所需的降解反应。该项目检验了这样一种假设，即可以通过战略操作安装在污染羽流附近的井来加强对受污染地下水的就地修复，其目标是促进处理溶液和受污染地下水之间的界面的伸展和折叠，从而增加发生降解反应的机会。该项目包括数值模拟和优化，以调查将最大限度地降低污染物的油井作业策略。该优化考虑了井的数量、井的位置以及每口井抽出或注入流体的速度作为时间的函数。这项研究使用一套现代地下水模型研究了均质含水层和非均质含水层中溶解的污染物和吸附在含水层固体上的污染物。井位、抽水方案和含水层属性之间的相互作用将由一系列可用于补救系统设计的无量纲数字来表征。污染威胁着重要的地下水资源，这些资源为许多市政自来水公司和家庭水井提供供水。美国已经花费了数十亿美元修复受污染的地下水，但在许多地方，修复工作并未达到清理目标。这个项目调查了一种方法，通过使用注水井和抽水井(一种现有的技术)以一种新的方式改善受污染地下水的清理，以促进地下水就地修复。该项目对这些新方法可实现的强化混合提供了初步的理论探索，并将在污染物降解的完整性、成本和地下水质量改善方面与现有方法进行比较。此外，这项研究提供了已建立的混沌理论和地下水流动之间的新联系，这将导致对地下污染物传输的新见解。该项目还将创建一个物理演示仪器和教育模块，通过允许用户通过注入和提取来操纵羽流，让大学预科学生学习地下水。完成后，该设备将通过科罗拉多大学博尔德分校建立的教学实验室藏品提供。

In situ remediation of contaminated groundwater often requires the introduction of a treatment solution into the aquifer in order to promote contaminant degradation reactions. A significant challenge for in situ remediation is the inherent difficulty of mixing in porous media. Without sufficient mixing of the treatment solution and the contaminated groundwater, the degradation reactions required to achieve in situ remediation cannot occur. This project tests the hypothesis that in situ remediation of contaminated groundwater can be enhanced through strategic operation of wells, installed near the contaminant plume, whose goal is to promote stretching and folding of the interface between the treatment solution and contaminated groundwater, thereby increasing the opportunity for degradation reactions to occur. The project involves numerical simulation and optimization to investigate well operation strategies that will maximize contaminant degradation. The optimization considers the number of wells, their locations and the rates at which each well extracts or injects fluid as a function of time. The study investigates both dissolved contaminants and those sorbed to the aquifer solids in homogeneous and heterogeneous aquifers using a suite of modern groundwater models. The interplay of the well placement, pumping schemes, and aquifer properties will be characterized by a series of dimensionless numbers that can be used for remediation system design. Contamination threatens important groundwater resources that provide the water supply for numerous municipal water utilities and domestic water wells. Already, billions of dollars have been spent on remediation of contaminated groundwater in the U.S., and yet at many locations, the remediation efforts have not met cleanup targets. This project investigates a method for improving the cleanup of contaminated groundwater by using injection and extraction wells (an existing technology) in a novel way to promote in situ groundwater remediation. This project provides an initial theoretical exploration of the enhanced mixing achievable by these novel methods that will be compared with existing methods in terms of contaminant degradation completeness, cost, and groundwater quality improvement. Additionally, this study provides a new link between established chaos theory and groundwater flow that will lead to new insights into subsurface contaminant transport. The project will also create a physical demonstration apparatus and education module that will be used to engage pre-college students in learning about groundwater by allowing users to manipulate plumes by injection and extraction. After completion, the apparatus will be available through an established teaching laboratory collection at the University of Colorado at Boulder.