The Geological Survey of Denmark and Greenland (GEUS) builds knowledge of the entire water cycle and contributes with high quality knowledge in all subsurface and drinking water supply matters. With the purpose to strengthen GEUS’ competencies within technology development for resource recovery and circular solutions to water related problems, the Department of Geochemistry offers a full time 3-year position as PhD student, with enrolment at the PhD School of SCIENCE and affiliation to the Department of Plant and Environmental Science (PLEN) at the University of Copenhagen. The position will begin in May 2024, but there is some flexibility in starting date.

Project description
Many waste streams from essential services, such as drinking water treatment, have long been viewed as worthless by-products that require disposal via costly and unsustainable landfilling. However, the value of these waste streams is currently being redefined. Specifically, arsenic (As) has a global reputation as a toxic contaminant in drinking water, but in 2023, As was classified as a Critical Raw Material (CRM) in the EU and USA due to its growing use in high-value products needed for the Green Transition, including batteries and high-speed electronics. In addition, phosphorus (P) and antimony (Sb) are also valuable CRMs that occur at high levels in waste streams, including drinking water treatment sludge and the ash from municipal solid waste incinerators. With the recent CRM classification of P, As and Sb, these elements are also subject to the EU’s CRM Act, which sets recycling benchmarks for domestic production of all CRMs.

Unfortunately, these waste streams continue to be viewed by the water treatment and waste management sectors with a linear-economic perspective, rather than being tapped for their high CRM recovery potential. This is largely due to the technical challenges of separating and upcycling P, As and Sb from heterogenous waste mixtures.

This project aims to develop new CRM recovery technologies that extract P and As from drinking water treatment sludge and P and Sb from incinerator fly ash and convert each element into valuable compounds. These technologies will be based on chemical and electrochemical methods to first separate each CRM from their specific waste stream and subsequently purify and valorize each CRM. These objective can be performed, for example, by exploiting the different (electro)chemical properties of P, As and Sb, such as reduction potential, aqueous chemistry or affinity for binding to mineral surfaces. The PhD student will focus primarily on P, but will work closely with senior and post-doctoral researchers investigating As and Sb recovery from the same waste streams. This project also includes many potential opportunities for international research stays and field work in Berkeley, California and South Asia (i.e., West Bengal, India), where As contamination of groundwater poses a catastrophic health threat. Based on the potentially wide range of methods that can be used to recover resources from these wastes, a variety of expertise can contribute to this project. Therefore, qualified PhD students can have diverse technical backgrounds and interests, including environmental engineering, soil, environmental, physical, geo- and colloid chemistry and materials science.

The project is a collaboration between the Department of Geochemistry at the Geological Survey of Denmark and Greenland (GEUS) and the Plant and Environmental Science (PLEN) Department at the University of Copenhagen. As such, the PhD student will be employed by GEUS with co-supervision by a senior researcher in the Department of Geochemistry and will be enrolled at UCPH with co-supervision by PLEN faculty.

Read more about the possibilities and tasks in the PhD programme here, and for information on eligibility of completed programmes, see General assessments for specific countries.

Your qualifications
The appointment will be made on the basis of academic qualifications. You should have a MSc degree in environmental engineering, (nano)-geochemistry, electrochemistry, materials science or similar field or equivalent qualifications, and hands-on laboratory experience. The PhD student is also expected to have the following qualifications and interests:

  • Previous field work experience or interest in developing field work expertise is a plus, particularly in rural areas of South Asia
  • Interest or experience in synchrotron-based X-ray absorption spectroscopy and high-energy X-ray scattering methods to probe the structure and surface chemistry of (nano-scale) minerals is also a plus.
  • Curious and creative mind-set with a strong interest in technology design and sustainable solutions.

Ability to teach undergraduate courses and proficiency in electrochemical methods is an advantage. But most importantly, we are searching for a highly talented, independent, motivated, and self-driven person who enjoys interfacing with researchers from different disciplines.

Further information on application
Please contact the Head of the Department of Geochemistry at GEUS, Claus Kjøller, e-mail: or Senior Researcher, Case van Genuchten, e-mail:

Department of Geochemistry at GEUS
The aim of the Department of Geochemistry is to understand the fate of chemical substances in soil, groundwater, drinking water, and the deeper subsurface. The activities are characterised by both experimental work in the laboratory, field tests, and numerical modelling. The fate of pesticides and other xenobiotics in soil and groundwater is one of the department’s core research areas. Another research area includes the understanding of hydrogeochemical processes during CO2-rock interaction in soil, groundwater aquifers, water treatment facilities, and geothermal reservoirs. We also process groundwater chemistry data in relation to monitoring of the Danish groundwater. We are a staff of about 40 persons, comprising researchers, consultants, postdocs, PhD students, and technicians.

What GEUS offers

  • A creative and interdisciplinary research environment
  • A lively and informal working environment with talented and dedicated colleagues
  • Versatile work duties and good opportunities to influence them
  • Development opportunities with access to courses and other further education
  • Family friendly workplace with flexible hours
  • An active social environment, with a staff association and art society
  • Fitness centre with physiotherapy at the workplace

Salary and conditions of employment
In accordance with the collective agreements between the Danish Ministry of Finance and the relevant eligible trade union.

The appointment requires that the student can be enrolled in the PhD programme at the University of Copenhagen. Read more about the rules and requirements here.

The appointment area is the Danish Ministry of Climate, Energy and Utilities and its institutions.

The Danish Ministry of Climate, Energy and Utilities considers diversity to be an asset and invites anybody interested, regardless of gender, age, religion or ethnicity to apply for the position.

Further information
Please contact the Head of Department, Claus Kjøller, on tel. +45 5172 8202, e-mail: or Senior Researcher, Case van Genuchten on tel. +45 9133 3433, e-mail:

Foreign applicants can read more about living and working in Denmark on GEUS’ website:

The application must include a CV, bachelor and master’s certificate or a pre-approval of your thesis and any contact details of referees (max. 2). If the master’s degree has not yet been completed or the certificate has not been issued, a statement from the supervisor is required stating the expected completion date and whether the candidate is suitable for PhD study.

You can send your application by clicking on the “Apply for position” (“Søg stillingen”) button. Your application must be with GEUS no later than 8 March 2024.

Applications received after the deadline will not be considered.

Please write in your application that you've seen the job at Jobfinder