Award-winning paper describes the ‘state of the science’ on wastewater surveillance of SARS-CoV-2.

The award-winning paper is ‘Minimizing errors in RT-PCR detection and quantification of SARS-CoV-2 RNA for wastewater surveillance’ and it was published in 2022 in the scientific journal Science of the Total Environment. It was cited 64 times in 2024, leading the field of KWR peer-reviewed articles that year. It therefore won the Willem Koerselman Prize, which was presented to co-author Gertjan Medema by Chief Science Officer Milou Dingemans during a festive ceremony at KWR. Dingemans:  “A broad consortium of researchers, after developing the new scientific concept of ‘wastewater surveillance’, has now thought about which factors can lead to erroneous conclusions, and how to tackle them. This is very useful: this method is increasingly widespread in health research and the water sector.”

Collective knowledge in a single paper

The high number of citations results from the popularity of wastewater surveillance, believes Medema. “And it pays off to collaborate with several authors because that results in a sort of snowball effect with citations. In this case, all the credit goes to the lead author, Australian researcher Warish Ahmed. He has already published widely on the subject and was able to bring together an impressive number of people. It is quite a feat to bundle all the collective knowledge in a single paper.”

Measuring the right things

The paper describes at a higher level of abstraction how RT-PCR technologies can be used in wastewater surveillance, says Medema: “The focus is not so much on the methods as such but on the elements you have to watch out for. KWR contributed knowledge about selecting sampling locations and how you have to collect samples. Because the phase before the laboratory work is also very important. In addition, during the process of bundling our knowledge, we noticed that researchers from other institutes were sometimes looking at a slightly different piece of genetic material in the SARS-CoV-2 virus with PCR. When they analysed wastewater samples from 2019 that they still had in the freezer, they also found a positive signal. That would have implied that the virus was already present in their locality before 2020. But these signals turned out to be false positives. We included experiences of this kind in the paper. That was a warning: make sure you measure the right things.”

Recurring award

Microbiologist Medema and his team also received the Willem Koerselman Prize in 2020 for the most cited paper in that year on COVID-19 wastewater research. In that article, KWR led the way in using this tool to see what was happening with the virus in society as a whole during the corona pandemic. The researcher is quite down-to-earth about the repeat award. “Those scientific citations are very nice, of course, but KWR’s motto is ‘Bridging Science to Practice’. So I think it’s mainly wonderful to see that, in the pressured context of the pandemic, our knowledge found its way into practice so quickly and so widely. The fact that wastewater surveillance has become more and more commonplace, even after the pandemic, is fantastic.”

Future-resilient technology

Now that this paper has made its mark on wastewater surveillance for SARS-CoV-2 during the 2020 corona pandemic, the question of its ‘shelf life’ has become moot. How relevant are the results now in 2025 and looking to the future? “PCR continues to be the method at the heart of the detection and quantification of the SARS-CoV-2 virus,” says Medema. “But in the meantime, we have also broadened and deepened our understanding. For example by working with the Erasmus Medical Centre to look at variants of SARS-CoV-2. You need next-generation sequencing for that work. And we are also looking at other respiratory viruses such as the RS virus or flu virus. With municipal health services, we are also looking at things like hepatitis A or the mpox virus. To some extent, we can fall back here on the knowledge we developed for COVID-19. However, additional knowledge is also needed for new viruses. In addition, we helped the World Health Organization to establish guidance for countries to identify the pathogens for which wastewater surveillance has most public health value. It would be nice to have a method to detect and quantify all viruses. Even though things are developing rapidly, we haven’t reached that stage yet.”

Widening the scope of wastewater surveillance

Widening wastewater surveillance to include other viruses is a significant development, believes Medema. “In June, the global congress of microbiologists WaterMicro will be in Amersfoort. KWR is one of the organisers. The congress takes place under the banner of the International Water Association and I have seen that no fewer than a quarter of all the submitted papers are about wastewater surveillance. In addition, we are also working at KWR on the question of how we can help countries like Ivory Coast and Uganda to extend the scope of wastewater surveillance. The circumstances there are very different from those here. I hope our paper will help with the optimal professionalisation of wastewater surveillance in practice. Because applying the best possible quality of method and sampling method gives the best possible result.”

What is the Willem Koerselman Prize?

Since 2009, KWR has awarded the Willem Koerselman Prize to the author working at our institute who has been cited most in the past year. It inspires researchers to make clear the impact of research on the water sector. The prize is named after KWR researcher Willem Koerselman, who remains in the lead with his publication ‘The vegetation N:P ratio: A new tool to detect the nature of nutrient limitation’ (1996) in the Journal of Applied Ecology with co-author Arthur Meuleman. The number of citations for that paper is now 2,124, a wonderful achievement and an example for anyone committed to the water sector.

Willem Koerselman Prize 2024

Willem Koerselman hands over the 2024 Willem Koerselman Prize

Willem Koerselman Prize 2024

Willem Koerselman Prize 2024