Role of Micro and Macro-Heterogeneities in Electro-Kinetic Soil Cleaning: An Area-Averaging Approach with Dynamic Simulations

Worldwide, the possibility of drinking contaminated groundwater is away of people’s minds. Annually published drought maps of the United States by NASA, and precipitation ranks reported by NOAA show how the ground-water heads and precipitations continue to decrease. This might be indicial information about how close the world could be of having underground reserves as the unique resource of water. Therefore, the cleaning of these resources would become a key priority. Social-economic activities such as electricy production based on fossil fuels are being developed on a daily basis on the soil surface are affecting the quality of groundwater. Reliable predictions about transport of contaminants in soils are required for decision-makers to develop technologies in order to prevent or remediate soil and groundwater pollution. Most of the studies realized are based on experimental efforts. Thus, additional investigation based on mathematical and computational modelling is a high need.

An analytical continuum-mechanics based model is developed in order to predict the dynamic transport of heavy metals through porous media when remediation processes are being applied. Electro-kinetic soil remediation has been found to be (potentially) an efficient solution to remove in-situ different types of pollutants. However, comparative analysis of the efficiency of this and other transport cases from a transient continuum-mechanics based model have not been studied. The model developed in this dissertation incorporates most of the driving forces acting on electro-kinetic soil remediation treatments, including diffusion, convection and electromigration. In addition, the model also captures the heterogeneities present within the soil matrix at two different scales: at the microscale, through the use of two capillary geometries, i.e. rectangular and cylindrical; and at the macroscale, by using the angle of inclination of the capillary domain. Simulations are performed in order to illustrate the effects of different variables on the pollutant concentration profile. Findings are applicable to the design of new porous materials such as geotextiles, selection of nuclear waste disposals, and to set preventive environmental regulations.