Sanne J. Smith is an assistant professor at TU Delft, The Netherlands, in the department of Water Management at the Faculty of Civil Engineering & Geosciences. Here, she leads a research program to develop, improve and understand water treatment to minimize the impact of industrial processes on the environment. She believes a holistic approach is required for industrial water use to achieve sustainable solutions. She obtained her Ph.D. at the Swedish University of Agricultural Sciences under the supervision of Professor Karin Wiberg. Her PhD thesis was centered on innovative treatment technologies for PFAS-contaminated water, and she mostly worked on foam fractionation and electrochemical oxidation. She has a double bachelor degree in chemistry and chemical engineering from the University of Groningen and a Master’s in water management from TU Delft.
Your recent Emerging Investigator Series paper focuses on a quantitative measure of net health benefits of treating PFAS in drinking water using granular activated carbon by examining the trade offs in reducing PFAS versus increased particulate matter emissions and climate risk. This is your first publication in ESPI! How has your research evolved from your earliest work to this most recent article at the start of your research career?
This paper represents a bit of a shift for me, since it is much more interdisciplinary than my previous publications. Throughout my under-/postgrad studies, I mostly worked on optimization problems: How can we best remove PFAS from water? My focus is on technology development, and I simply took the need for PFAS removal as a given. Throughout the final stages of my PhD, however, I started getting more interested in the ‘why’ of PFAS removal. It is extremely resource-intensive to treat PFAS in water, and I noticed that most cost-benefit evaluations ignored the secondary impacts of the treatment technologies. That is the research gap that we tried to address in the current publication, which required completely different methods than my usual work.
Although you did your PhD at the Swedish University of Agricultural Sciences in Uppsala, you previously studied in The Netherlands for your Bachelor and Masters degrees. How does it feel to be back in The Netherlands establishing yourself as an independent research leader?
Honestly, it still feels a bit unreal. I applied to my current position with a ‘they probably won’t hire me without a postdoc but I might as well try’ mentality, so the job offer came as a big surprise. I am currently staff in the same department as where I was a masters student, so it took some time to convince everyone (including myself) that I am not a student anymore, but I am getting there!
What aspect of your work are you most excited about at the moment?
I am currently supervising a PhD student who is investigating if foaming on existing wastewater treatment plants can be used to remove PFAS. If successful, this could be an extremely cheap and benign way to prevent high amounts of PFAS from entering the environment. The research topic is quite niche, I believe there are only two groups in Australia and the US working on the same idea. The student is doing a great job and it is nice to be in contact with particularly the Australian group, to share our enthusiasm and ideas. The project is industry-funded and we are already moving to full-scale tests, so it is also amazing to see real-world impact so quickly!
In your opinion, what are the most important questions to be asked/answered in this field of research?
The question that we asked in this ESPI publication is definitely important: should we even always try to remove all PFAS from water? Our publication only answered a very small and specific part of that question, so more research is definitely warranted. I recently learned the term ‘temporary tolerance of presence’, which implies that it is sometimes better to simply accept that PFAS are there and focus your removal/prevention efforts elsewhere. As someone who is predominantly in the water treatment field, it is tempting to focus exclusively on the development of better technologies, but prioritizing where PFAS treatment makes most sense is maybe more impactful.
What do you find most challenging about your research?
Definitely keeping up with all developments. PFAS is such a hot topic right now, so there are publications, start-ups and projects popping up every day. It can be difficult to distinguish between what is truly promising versus what is overhyped.
In which upcoming conferences or events may our readers meet you?
I am currently involved in the organization of the ‘Water in Industry’ conference, an IWA conference that will be held in Delft at the end of June 2026. Abstract submission will open very soon, so please join me there! I usually attend SETAC Europe meetings as well.
How do you spend your spare time?
I play beach volleyball, which I do 3-4 times a week during summer. We live close to the beach, so it is a great way to empty my mind, enjoy the fresh air (including the PFAS in the sea spray…) and be active!
Which profession would you choose if you were not a scientist?
I would probably become a water treatment engineer in an industrial environment. It seems silly, but I love working at landfills: leachate water is extremely interesting (because it’s so dirty) and there is a lot of good you can do when treating it correctly. The flows are also quite small compared to other types of water, which means that unconventional technologies become possible.
Can you share one piece of career-related advice or wisdom with other early career scientists?
I have been extremely lucky to always be part of close-knit networks, so I highly recommend everyone to befriend their colleagues. I was one of the 15 PhD students in the PERFORCE3 project, and we became very close, both personally and professionally. In my current department, there are eight assistant professors who all started around the same time, and I could not have written this ESPI publication without the two of them who are co-authors.
