UnSAT-EIE - Coupling Soil Aquifer Treatment and Engineering Injection and Extraction to Enhance Mixing at the interface between the Saturated and the Unsaturated Zone

• Applicants: Dr.-Ing. Mónica Basilio Hazas; Professor Dr. Gabriele Chiogna
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 556289210

Groundwater remediation strategies and water reclamation techniques often depend on the effectiveness of mixing of fluids in the subsurface. While mixing is typically a slow process in Darcy flows, it can be enhanced by transient conditions. Transient flows can be generated by engineered-injection and extraction (EIE) techniques, consisting on different setups of pumping wells. However, in the vadose zone, the water content is relatively low and thus EIE systems are less efficient. In such cases, soil-aquifer treatment (SAT) systems, consistent of intermittent infiltration basins, allow mixing during the infiltration process. Since water fluxes and water content in the vadose zone are higher under SAT conditions, EIE could be applied in aquifers with a deep unsaturated zone. This proposal aims at coupling EIE with SAT to enhance mixing processes at the fluctuating capillary fringe and water table. Specifically, we propose to perform laboratory bench scale experiments (quasi two-dimensional flow-through chamber) with a model-based interpretation, and to model realistic field scale scenarios. The proposed research also involves the development of a new methodology to map solute concentration in both saturated and unsaturated zones in flow-through experiments, combining geophysical and optical methods. Overall, this work will provide a better understanding of mixing processes at the interface between the saturated and the unsaturated zone, and will test the capabilities of coupled EIE and SAT to enhance mixing processes. Moreover, modelling a realistic scenario based on an existing soil aquifer treatment facility could open the possibility of applying the developed methods in the future.

• DFG Programme: Research Grants
• International Connection: Israel
• International Co-Applicant: Professor Alex Furman, Ph.D.