Date of Award
Civil and Environmental Engineering
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The main objectives of this research are to evaluate MnO2 plugging effects on remedial efficiency of pooled tetrachloroethylene (PCE) using KMnO4 solution under a high pH condition, to develop and test a three-dimensional numerical model, and to validate the model with experimental data. Additional studies conducted to achieve the thesis objectives include kinetic studies of KMnO4 oxidation with PCE at high pH. The kinetic studies of KMnO4 oxidation of PCE were conducted using a sodium carbonate solution (1 g/l, pH = 10.6 +/- 0.1) at three different temperatures (5, 10, and 20°C) and three KMnO4 concentrations (0.2, 1, and 5 g/l). Extensive kinetic studies suggest that the overall oxidation is a second-order reaction and pseudo-first-order with respect to PCE and KMnO 4, respectively. The second-order rate constant and the activation energy were 0.028 +/- 0.001 M-1s-1 at 20°C and 43.9 +/- 2.85 kJ/M, respectively. A two-dimensional KMnO4 oxidation experiment to remove a PCE pool has been conducted for nearly one year to investigate the reactive transport behavior of the system under a variety of conditions. A high pH buffered solution (10.5) was used to reduce carbon dioxide degassing. Effluent Cl- concentration was measured to determine PCE removal rate and used for numerical model validation. Experimental results obtained during the KMnO 4 flush show that MnO2 appears to reduce the permeability in the reaction zone and hence reduce the PCE removal rate. Approximately 50% of the PCE mass was removed after 200 days. Removal rate increased with increasing KMnO4 concentration and averaged approximately 25 times greater than through dissolution alone with an injected KMnO4 solution at 10 g/l. RT3D and MODFLOW codes have been partially coupled to simulate the oxidation processes. Permeability reduction due to presence of dense non-aqueous phase liquid (DNAPL) and MnO2 precipitation is incorporated in MODFLOW. In this work, numerical simulation results provide a reasonable match to experimental data indicating that the numerical model including assumptions, numerical approach, and functional equations for MnO2 plugging and mass transfer, are reasonable for conditions used in the two-dimensional experiment. Numerical simulation results show that MnO2 plugging has adverse effects on NAPL removal rate at later stages of a KMnO4 flush. Results suggest that a method to reduce MnO2 precipitation will improve removal rates and may even be necessary before KMnO4 can completely remove DNAPL mass.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .D345. Source: Dissertation Abstracts International, Volume: 65-07, Section: B, page: 3588. Adviser: Stanley Reitsma. Thesis (Ph.D.)--University of Windsor (Canada), 2003.
Dai, Qunli, "Laboratory study and numerical simulation of permanganate oxidation of pooled tetrachloroethylene." (2003). Electronic Theses and Dissertations. 2563.