Salaices Avila, M: Experiment and Modelling

The transport of multiple solutes in natural aquifers may be influenced by the hydrologic, geologic and environmental conditions. A competitive sorption may take place, increasing the complexity of the mechanisms that could define the transport and fate of the substances. An understanding of the competitive sorption and the multiple factors that could influence it were investigated. Column experiments were conducted to investigate the transport and the competitive sorption of trichloroethene (TCE) and 1,2-cis-dichloroethene (cis-DCE) in porous media. These compounds were selected as model contaminants, due to their widespread study, and because they are found in many aquifer sites like in Lauf a.d. Pegnitz (Germany). The column experiments were designed to simulate real conditions as in the aquifer. The liquid samples from the effluent of the column were analysed with a method developed in this work for the analysis of water samples containing chlorinated ethenes based on the Headspace-Solid-Phase Micro Extraction, HS-SPME, technique followed by Gas Chromatography, GC-FID. The optimal conditions for the sampling and analysis were established. The analytical method proved to be fast (within minutes) and it permitted to acquire reliable and highly reproducible breakthrough data in a relatively short period of time. The experimental breakthrough curve data was modelled with a numerical routine developed for this thesis, called NEMMCS and written in Fortran. A robust and stable method was selected and further developed to solve the advection-dispersion transport equation based on the Moving Concentration Slope technique, and adapted in this thesis for the transport of multiple solutes. The program is capable to solve the transport equation under equilibrium conditions or under kinetically controlled conditions. The two site kinetic model was implemented with the reversible non-linear kinetic model, the reversible bilinear model, and the pore diffusion model. The