Thesis (Ph. D.)--Ohio State University, 1975. / Includes bibliographical references (leaves 164-167). Available online via OhioLINK's ETD Center.

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Thesis (M.Eng.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 107-116.

This research reports on an experimental and theoretical study of soil heating/air stripping and steam injection/vacuum extraction for remediation of MTBE and Diesel Contaminated Soils. Two one-dimensional mass transfer models were using to simulate the process of remediaction. Contaminant kinds(MTBE and Diesel)¡A contaminant concentration (152~13,912 mg/kg soil)¡Asoil temperature(38~120¢J)¡Asteam injection pressure(0.5~1.0 atm)¡A and the mass of steam used(0.379~0.730 kg/h)were employed as the experimental factors in this study. In soil heating/air stripping study, rising soil temperature will enhance the MTBE removed efficiency¡A it was shown in the concentration of effluent gas. Further, the flow rate at outlet of column was higher than that at inlet of column, it revealed MTBE transfers from liquid phase to gas phase and was removed by gas flow. The concentration of effluent gas curve in low initial MTBE concentration test was similar with high concentration test, but the mechanisms was quiet different¡Ait need advanced adsorption test to find the reasons. In medium initial MTBE concentration test¡Athe concentration of effluent gas curve showed linear shape. When using steam injection/vacuum extraction treating MTBE contaminated soil, it showed 90¢Mefficiency can be reached in one hour. In steam injection/vacuum extraction study, it showed higher initial diesel contaminant concentration¡Ahigher initial concentration of effluent gas. Further, in high initial diesel concentration test (13.912 g diesel/kg soil test and about 5g/ kg soil tests)¡Athe concentration of effluent gas curves had a dominant drop at early time in remediation, it revealed the injection steam flow was quiet large, so diesel didn¡¦t has enough time to transfer to gas phase, that the gas couldn¡¦t been saturation at outlet of column. But in low initial diesel concentration test (about 1 g diesel/kg soil tests), the concentration of effluent gas curves showed the typical NAPL remediation curve. The different with in high and low initial concentrations might from the complex composition of diesel. Because at the early time in remediaction of high initial diesel concentration, the low carbon numbers diesel could abundantly evaporate, it caused the high concentration of effluent gas. With the remediation time go by, the low carbon numbers diesel exhaust. So the main composition of effluent gas transfer to high carbon numbers diesel, that the concentration of effluent gas curve showed the slowly decline. For high initial diesel concentration test (13.912 g diesel/kg soil)¡A the efficiency was the highest (73.7¢M). For low initial diesel concentration test (about 1 g diesel/kg soil), the efficiency was the lost (about 20¢M). Further, the remediation of diesel contaminated soil exited a rapid removed period. Under the conditions of this study, the rapid removed period could remove more than 95¢Mcontaminant of diesel removed at hold remediation time. The experiment results also showed that larger the mass of steam injection, shorter the rapid removed period, and larger the steam injection pressure, longer the rapid removed period. When using soil heating/air stripping treating diesel contaminated soil, the removed efficiency was worse 10-20¢Mthan the same initial diesel contaminated concentration. In simulating remediation process, the prediction with the MTBE measured concentration yielded good agreement in NAPL model. But to get the better fit of diesel in NAPL model, it might set the ¡§could removed mass¡¨ to initial condition of model. In non-NAPL model, MTBE also showed good agreement with model, and the model enabled the prediction of the initial contaminant level in the soil.

A thermo-elastic-plastic model for unsaturated soils has been presented based on the effective stress principle considering the thermo-mechanical and suction coupling effects. The thermo-elastic-plastic constitutive equations for stress-strain relations of the solid skeleton and changes in fluid content and entropy for unsaturated soils have been established. A plasticity model is derived from energy considerations. The model derived covers both associative and non-associative flow behaviours and the modified Cam-Clay is considered as a special case. All model coefficients are identified in terms of measurable parameters. To verify the proposed model, an experimental program has been developed. A series of controlled laboratory tests were carried out on a compacted silt sample using a triaxial equipment modified for testing unsaturated soils at elevated temperatures. Imageprocessing technique was used for measuring the volume change of the samples subjected to mechanical, thermal and hydric loading. It is shown that the effective critical state parameters M, ???? and ???? are independent of temperature and matric suction. Nevertheless, the shape of loading collapse (LC) curve was affected by temperature and suction. Furthermore, the temperature change affected the soil water characteristic curve and an increase in temperature caused a decrease in the air entry suction. The simulations from the proposed model are compared with the experimental results. The model calibration was performed to extract the model parameters from the experimental results. Good agreement between the results predicted using the proposed model and the experimental results was obtained in all cases.

A thermo-elastic-plastic model for unsaturated soils has been presented based on the effective stress principle considering the thermo-mechanical and suction coupling effects. The thermo-elastic-plastic constitutive equations for stress-strain relations of the solid skeleton and changes in fluid content and entropy for unsaturated soils have been established. A plasticity model is derived from energy considerations. The model derived covers both associative and non-associative flow behaviours and the modified Cam-Clay is considered as a special case. All model coefficients are identified in terms of measurable parameters. To verify the proposed model, an experimental program has been developed. A series of controlled laboratory tests were carried out on a compacted silt sample using a triaxial equipment modified for testing unsaturated soils at elevated temperatures. Imageprocessing technique was used for measuring the volume change of the samples subjected to mechanical, thermal and hydric loading. It is shown that the effective critical state parameters M, ???? and ???? are independent of temperature and matric suction. Nevertheless, the shape of loading collapse (LC) curve was affected by temperature and suction. Furthermore, the temperature change affected the soil water characteristic curve and an increase in temperature caused a decrease in the air entry suction. The simulations from the proposed model are compared with the experimental results. The model calibration was performed to extract the model parameters from the experimental results. Good agreement between the results predicted using the proposed model and the experimental results was obtained in all cases.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2007. / Thesis documentation sheet inserted. Includes appendix of four papers and manuscripts, three co-authored with others. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.

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