HCET: a finite element model for solute transport driven by hydraulic, chemical, electrical, and thermal gradients

Abstract

There are many alternatives to remediate contaminants in coarse-grained soils. However, most of these methods fail to accomplish their task in fine-grained soils. When a single driving force dominates and other cross effects are less important, direct flow conduction phenomena is main concerned in the study of contaminants transport. In the thermodynamics of irreversible processes, any driving force may give rise to any flux. For example, electrical gradient and hydraulic gradient both may cause the flow of water. Increased concerns over the environment have the need to better understand the behavior of the fine-grained soil barriers. Geotechnical engineers have been given attention on coupled transport processes on electrokinetic's remediation. The computational capability available to the geotechnical engineers has also strongly influenced the engineer's ability to address these complex problems. This dissertation presents solute transport driven by the hydraulic, chemical, electrical, and thermal gradients including: 1) introduction, 2) literature review, 3) mathematical development, 4) finite element formulation, 5) evaluation of the HCET model, and 6) conclusions, summary, and future studies. The study was extended by simulating experimental results on thermal effects of electrokinetic's remediation of lead removal available in the literature. The numerical model HCET was developed to simulate the coupled transport processes as a function of time. The HCET model has a few advantages over other models and shows that: 1) The model is capable of handling very general case with one-variable to four-variable problems, 2) The model is capable of exploring heat effects in the field of electrokinetic's remediation, 3) The model uses a simultaneous algorithm to solve these multiple variables of the coupled transport processes, and 4) The HCET model can be used to perform parameter analysis for the decision making and evaluation in fined-grained soil application.