Date of Award
Doctor of Philosophy (PhD)
Civil and Environmental Engineering
Yalcin B. Acar
Roger K. Seals
A generalized mathematical model for electrokinetic soil processing is presented for multi-species transport of reactive components under electric fields in two-dimensional geometry, based on the earlier Acar-Alshawabkeh model. In this model, sets of partial differential equations are formulated for the transport of fluid, charge, and species in a saturated soil under coupled hydraulic, electrical, and chemical potentials. Chemical reactions pertaining to sorption, precipitation/dissolution, aqueous phase equilibria, water autoionization, and electrolysis are included in the new model. The boundary conditions corresponding to the mass transport equations are described. A program, EK-SIM (ElectroKinetic Soil Processing SIMulation), has been developed to simulate electrokinetic soil processing. The finite element method is used to solve the mass transport equations. Eight-node, quadrilateral isoparametric elements are used in space discretization. The finite difference technique is used in time discretization. The developed code is verified by comparison to one-dimensional analytical solutions of nonreactive chemical transport with Dirichlet and Neumann boundary conditions. The basic model predictions agree perfectly with the analytical solutions. The model has been further evaluated by comparison with a bench test of the electrokinetic injection of ammonium and sulfate ions into a sand bed to enhance bioremediation and a pilot-scale test of electrokinetic lead extraction from kaolinite. The model predictions are in reasonable agreement with the experimental results and the model successfully simulates the effects of chemical reactions on species transport in the unenhanced lead remediation test. The developed model will provide a useful tool to attain a better fundamental scientific understanding of electrokinetic soil processing and for the design/analysis of full-scale, in situ applications.
Zheng, Wenbing, "Numerical Modeling of Multi-Species Transport in Soils Under Electric Fields." (1998). LSU Historical Dissertations and Theses. 6643.