Dr. Niels Hartog has over 20 years of professional scientific expertise in the fields of groundwater chemistry and environmental hydrogeology. He holds an MSc in Hydrogeology from the Vrije Universiteit Amsterdam (NL) and a PhD in Geochemistry from Utrecht University (NL). After a post-doctoral research position at the University of Waterloo (CA) focusing on contaminant hydrogeology he continued towards applied research and technology development. He focusses on the field of subsurface water technologies including Managed Aquifer Recharge (MAR, ASR), Aquifer Thermal Energy Storage (ATES) and Geothermal energy production.

At KWR Water Research Institute (NL) acts as a Principal Researcher for the Geohydrology team, is a member of KWR's Scientific Council and is responsible for quality assurance and supervision. As a subsurface specialist, he is a member of the  Information and Consultation Body Geothermal Energy for the Province of Utrecht.

In addition, Niels holds a part-time position at Utrecht University as a Guest Associate Professor in the Environmental Hydrogeology group. He has supervised over 30 MSc and 10 PhD students and has world-wide research collaborations on a wide range of environmental and hydrogeochemical topics. He has published over 40 articles largely in high-ranking international journals. He frequently acts as a reviewer for numerous scientific journals and research funding programs. Most recently he acted as a guest-editor for the journal Water for a special issue on "Water Quality Considerations for Managed Aquifer Recharge Systems" and was invited as a keynote speaker at the Geofluids conference in Budapest, Hungary in 2020.