PhD position on Fine Particles in Shallow Groundwater Systems

Job description The Department of Earth Sciences seeks a highly motivated PhD candidate with an MSc background in Earth Sciences, Physical Geography, Hydrogeology, Physics, Environmental Engineering, or related fields. You will work on the project “Fine Particles in Shallow Groundwater Systems: Origin, Mobilization, and Particle Clogging in Utrecht ATES Wells”. Society increasingly relies on groundwater pumping for seasonal energy storage, geothermal energy, drinking water production, urban development, and climate change mitigation. To pump and infiltrate groundwater, the placement of a well and positioning within the local stratigraphical sequence are essential to ensure capacity and longevity. In Utrecht, the uppermost aquifer is extensively used for Aquifer Thermal Energy Storage (ATES) systems that store seasonal thermal energy for building heating and cooling. Wells are placed in aquifers composed of coarse Middle Pleistocene sediments. Unfortunately, filters in these wells are highly susceptible to particle clogging, in many cases requiring far more intervention than originally anticipated. Once clogged by fine particles, wells require regeneration (unclogging) to restore pumping capacity. At present, there is no reliable method to predict when and where and how frequent wells will clog, nor is there a comprehensive analysis of which facies and filter combinations perform well and which require ongoing maintenance. Therefore, this collaborative project combines expertise in Quaternary Geology in the Department of Physical Geography (Dr Kim Cohen) with expertise in subsurface utilization and in modelling particle dynamics in the Department of Earth Sciences (Dr Thomas Sweijen). What you will do In this four-year study, you will unravel the relation between particle dynamics and the geology of Utrecht’s upper aquifer. You will combine subsurface data and mappings of Pleistocene fluvial and glaciofluvial sedimentology (poorly sorted, heterolithic, coarse and fine fractions mixed), with column-scale flow experiments and field-scale numerical modelling of groundwater flow and particle dynamics. With the aim of correlating local stratigraphic features, local groundwater flow near wells that causes particle mobilization, and clogging due to filtration, your work will explore the origins of problematic particles and identify vulnerable settings. You will extrapolate gained knowledge to benefit well design and operations in general. Utilizing existing well infrastructure at the Utrecht Science Park, we will conduct a field-scale investigation to test and showcase how particle dynamics and aquifer stratigraphy are intertwined. Key research questions you will address: What is the origin of the problematic fine particles, and what is the relation with local stratigraphy, its depositional history, filtering properties, and well capacities? What are the physical parameters governing problematic particle dynamics? Which well design choices and stratigraphical settings are prone to problematic particle mobilization, and how can this information be used to optimize ATES designs? Finding answers to these fundamental questions will directly support decision-making in sustainable subsurface engineering, enhance subsurface storage of both energy and water, and promote sustainable practices. Your development A personalised training programme will be set up, reflecting your training needs and career objectives. About 20% of your time will be dedicated to this training component, which includes following courses/workshops as well as training on the job in assisting in the Bachelor’s and Master’s programmes of the department at Utrecht University. Through interactions with other scientists, the Municipality of Utrecht, the Dutch Geological Survey, and industry partners, you will be exposed to diverse career paths in both academia and the applied sector, helping you shape your professional future. Your qualities You are a motivated team player with strong experimental and/or numerical modeling skills. You have completed (or will complete before the position starts) your MSc degree in Earth Sciences, Physical Geography, Hydrogeology, Physics, Environmental Engineering, or a related discipline. Non-Dutch MSc diplomas may be subject to specific approval by the Board for Conferral of Doctoral Degrees before you can be accepted into the PhD programme. Candidates already holding a PhD degree cannot be accepted for this position. Required qualifications: Strong analytical skills and ability to integrate field observations and experimental observations with computational approaches, including proficiency in at least one programming language (Python, MATLAB, or similar) for data analysis and modeling. Demonstrated experience with experimental techniques (e.g., flow-through experiments, column studies, material characterization) and/or numerical modeling of flow and transport in porous media Theoretical background and genuine interest in both Hydrogeology and Quaternary sedimentology. Motivation to work in a multidisciplinary environment that bridges fundamental research with societal applications, including willingness to engage with stakeholders from government and industry Excellent communication skills in English, both written and spoken. Desirable qualifications: Experience with modeling reactive transport, particle transport, or soil-fluid interactions. Previous exposure to interdisciplinary research connecting laboratory experiments with field-scale applications We highly encourage applicants from all members of our community and of diverse backgrounds to join us. Terms of employment We offer: a position (1.0 FTE) for 1 year, with an extension to a total of four years upon a successful assessment in the first year, and with the specific intent that it results in a doctorate within this period; a gross monthly salary between € 3.059 and €3.881 in the case of full-time employment (salary scale P under the Collective Labour Agreement for Dutch Universities (CAO NU)); 8% holiday pay and 8.3% year-end bonus; a pension scheme, partially paid parental leave and flexible terms of employment based on the CAO NU. In addition to the terms of employment laid down in the CAO NU, Utrecht University also offers a range of its own schemes for employees. This includes arrangements for professional development, various types of leave, and options for sports and cultural activities. You can also tailor your employment conditions through our Terms of Employment Options Model. In this way, we encourage you to keep investing in your personal and professional development. For more information, please visit Working at Utrecht University. How to apply For informal information (not for application) about this position, please contact Dr Thomas Sweijen, project leader, at T.Sweijen@uu.nl. To apply, use this link to the original advertisement on our own website and follow the guidelines there. E-mail applications cannot be accepted. Include the following information in your application: a letter of motivation, in which you describe why you wish to pursue this PhD position and what makes you the best candidate for it; also include why you wish to pursue your PhD in our department in general; your curriculum vitae, including any courses taken that are relevant for the position; academic credentials (mark sheets and degree statements) as far as already available and relevant. No reference letters need to be submitted in your initial application. If you are short-listed, we will contact you for referees. We aim for a quick selection procedure after the application deadline of June 21, 2026. Candidates must meet the requirements and must be able to start ultimately by January 1, 2027. Sooner is possible and preferred. In that perspective, note that international candidates that need a visa/work permit for the Netherlands require at least four months processing time after selection and acceptance. This will be arranged with help of the International Service Desk (ISD) of our university. Finding appropriate housing in or near Utrecht is your own responsibility, but the ISD may be able to advise you therewith. In case of general questions about working and living in The Netherlands, please consult the Dutch Mobility Portal. Online screening may be part of the selection. Commercial response to this ad is not appreciated.