| Nächste Überarbeitung | Vorhergehende ÜberarbeitungLetzte ÜberarbeitungBeide Seiten der Revision |
| thesis:stumpp2 [2013/12/12 14:49] – angelegt mweiler | thesis:stumpp2 [2017/01/18 11:22] – c.stumpp |
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| ===== Diffusive exchange of ideal and reactive tracers in a dual-permeable sediment column system ===== | ===== A new method to determine the amount of immobile water in a 2D aquifer ===== |
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| == Problemstellung == | == Problemstellung == |
| Sustainable use of water resources and their protection against pollution requires fundamental understanding of filter, buffer and storage functions of groundwater systems. Of particular importance are heterogeneous porous aquifers including zones with mobile and immobile water. Substances diffuse from high permeable areas into immobile zones with low permeability. Consequently, substances can be stored in such immobile water regions and their residence time in double-permeable aquifers is much longer compared to water residence times. However, it still remains unknown how the heterogeneity of an aquifer and time-dependent variability of the water flow influences the fate of substances in such systems. | Porous aquifers contain structural heterogeneities like different sediment layers or lenses. Of special importance are low permeable areas containing immobile water not actively contributing to transport. Solutes diffuse from high permeable areas into immobile water regions and can be stored there for a long time in comparison to residence times of mobile water. An often observed effect caused by the storage function of immobile water regions is a contaminant rebound after site remediation. In cases where the concentration gradient turns around solutes diffuse back from immobile water regions into mobile water regions resulting in a continuous release over a long time eventually exceeding thresholds at downstream located observation wells. |
| | Heterogeneity and the percentage of immobile water are often unidentified in natural aquifers. Hence, the mathematical prediction of solute transport taking regions with immobile water into account remains challenging. New methods are needed to determine the amount of immobile water in an unknown system (1) to calculate the storage capacity of immobile water regions for pollutants and (2) to evaluate the risk of a contamination rebound after site remediation. |
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| == Ziel der Arbeit == | == Ziel der Arbeit == |
| The objective of the thesis is (1) to conduct multi tracer experiments in dual permeable systems (impulse injection), (2) to investigate the influence of different flow rates on the diffusive exchange into immobile water zones and (3) to model experimental data to quantify observed processes. | The objective of the thesis is (1) to conduct multi tracer experiments in a well-defined 2D aquifer (Dirac injection) at different flow rates, (2) to model experimental data to quantify the amount of immobile water in the system using the Single Fissure Dispersion Model and (3) to directly and indirectly validate the applied model. |
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| == Methode == | == Methode == |
| The work will include the performance of multi tracer tests with bromide, deuterium and nitroaromatic compounds. Experimental data will be modelled using HYDRUS. | The work will include the performance of multi tracer tests with bromide and deuterium. Experimental data will be modelled using the Single Fissure Dispersion Model. |
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| == Betreuung == | == Betreuung == |
| Bastian Knorr, Piotr Maloszewski und Christine Stumpp | Christine Stumpp und Bastian Knorr |
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| == Besondere Hinweise == | == Besondere Hinweise == |
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| == Herausforderung == | == Herausforderung == |
| column experiments, multi tracer tests, modelling | 2-D aquifer experiments, multi tracer tests, modelling |
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| == Sprache == | == Sprache == |
| == Literatur == | == Literatur == |
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| Hünniger, M., 2011. Development of Experimental, Monitoring, and Mathematical Methods to Quantify Water Fluxes and Transport in Heterogeneous Aquifer System Models. Cuviller. | Levy, M., Berkowitz, B., 2003. Measurement and analysis of non-Fickian dispersion in heterogeneous porous media. J. Contam. Hydrol., 64(3–4): 203-226. |
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| | Knorr, B., Maloszewski, P., Krämer, F., and Stumpp, C. (accepted) Diffusive mass exchange of non-reactive substances in dual-porosity porous systems – a column experiment under saturated conditions. Hydrological Processes, doi: 10.1002/hyp.10620 |
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| Krämer, F., 2011. Diffusive exchange of non-reactive substances in bi-porous groundwater systems – a column experiment. Diploma thesis, Technische Universität Freiberg. | |
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| {{tag>master offen labor}} | {{tag>master labor vergeben}} |