Flow- and transport processes in heterogeneous porous media determine the distributions of fluid phases and chemical components in soil and groundwater. Continuum models, like Darcy- and Richards equation, are the standard basis for modeling and process understanding. The length scale at which the "heterogeneities" become statistical independent, determines the validity range of these models. Increasing evidence accumulated over the last decade suggests that long-range-correlations due to pore structure and fluid-fluid-interactions determine essentially the flow- and transport behaviour. Based on ideas of the statistics of disordered media and structural phase transitions new concepts, like fractal geometry, percolation theory, anomal random walking and universal scaling laws, are now applied to flow, dispersion and displacement processes. To gap the bridge between statistical and continuum description and the determination of effective transport parameters for the three-phase-system "gas-water-solid" on different length scales is the focus of our research activities. In strong interaction between experiment and modeling we investigate flow pattern, gas transport processes and mass transfer processes in bench-scale experiments for environmental-relevant scenarios. Besides natural processes like gas exchange between soil air and groundwater and the emission of greenhouse gases, we also consider technical applications like the direct gas injection into aquifers contaminated with organic pollutants.
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