Type of Document Dissertation Author Ahmad, Hafiz Author's Email Address email@example.com URN etd-11222004-215827 Title Evaluation and Enhancement of Electro-Kinetic Technology for Remediation of Chromium Copper Arsenic from Clayey Soil Degree Doctor of Philosophy Department Civil and Environmental Engineering, Department of Advisory Committee
Advisor Name Title Danuta Leszczynska Committee Chair James F. Tull Committee Member Amy Chan Hilton Committee Member Andrew Dzurik Committee Member Keywords
Date of Defense 2004-11-10 Availability unrestricted AbstractA relatively new technique of electro-kinetic remediation is examined to evaluate and enhance removal of residual of the CCA (chromated copper arsenate) from clayey soil. A short duration (25-hours) treatment approach was initiated for this purpose. Laboratory 1-D column tests were performed on kaolin soil under the influence of DC electric field. Different chemicals (acid, alkali and oxidizing agents) and tap water were purged through electro-osmotic flow to enhance chromium, copper, arsenic remediation. Configuration of electrodes/reactor setup was also adjusted to improve the removal efficiency of the CCA chemicals by inducing buoyancy with electro-osmotic flow. Interesting results were obtained showing up to 78% of arsenic and 72% copper removal by purging sodium hypo-chlorite (NaOCl). Sodium hydroxide (NaOH) purging also indicated enhanced removal with 74% arsenic and 72% copper removal. It was difficult to remove chromium and maximum removal was only 3.75% when the soil was purged with tap water. The batch experiments show that with respect to individual contaminant remediation, the removal efficiency increases many times when contaminants in the soil are in mixed-form. Inclined reactor setup showed enhanced electro-osmotic flow due to the effect of buoyancy.
A model combining main phenomena of contaminant movement: electro-migration, electro-osmosis, diffusion, and buoyancy was developed for a small Debye length. The model predicts the behavior of pH, which is an important parameter that governs the migration of contaminants. Calculation based on the model showed excellent agreement when compared with the pH profile of experimental data of tap water purging for copper remediation.
Although additional modeling and experimentation is needed, the results of this thesis demonstrate that electro-kinetic remediation with suitable purging chemicals may offer enhanced removal of polluted soil.
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