Prof. Gertjan Medema (M) is principal microbiologist at KWR since 1996. He is part-time chair on Water & Health at Delft University of Technology (Sanitary Engineering) since 2009 and was Visiting Hannah Professor on Water & Health at Michigan State University from 2018 to 2022.

His research focuses on understanding the transmission of infectious diseases and antimicrobial resistance via water systems, and how this can be prevented. This includes experimental, field and modelling research: the development of methods for detection and removal of pathogens such as viruses, bacteria, parasites and antimicrobial resistance in water, conducting Quantitative Microbial Risk Assessment, fate and transport and exposure modelling and epidemiological research on the health effects of water systems, and providing advice for the design of safe water systems and policies. 

At the start of the COVID-19 pandemic, he initiated research on sewage surveillance of SARS-CoV-2 and has published on this topic and was invited for keynotes by many organizations. The work inspired many research teams to start wastewater surveillance programs in their country or region. He coordinated the ‘second-opinion’ epidemiological investigation of the Legionella outbreak in Flint, Michigan.

He is advisor of WHO on microbiological (drinking) water guidelines and QMRA since 1991 on SARS and WASH in 2003, and via WHO of the European Commission on the EU Drinking Water Directive and water reuse guidelines. He has coordinated the joint research program of the Netherlands water utilities. He is director of KWR’s WHO collaborating centre on Water Quality & Health and advisor to the WHO on waterborne pathogens and QMRA since 1991 on SARS and WASH in 2003 and ebola and WASH in 2014 and on wastewater surveillance since 2020. He is advisor of EU DG Environment on water reuse guidelines and drinking water guidelines.