PhD students Roxana Cremer and John Hader during recording of "Danger Down the Drain" in June 2021.

Without wastewater treatment, diseases and infections would ravage our modern world. At the same time, wastewater treatment is something we often take for granted. What actually happens down the pipelines when the water we flush leaves the house? “Danger down the Drain” is the pilot episode in the podcast series  Insights to Science produced and hosted by PhD student Roxana Cremer at the Department of Environmental Science. The pilot episode explores the fragile nature of modern wastewater treatment, which can be disrupted by what we release down our drains, and what the possible solutions to that problem are.       

“Wastewater does not end up on the street or straight in the Baltic Sea or rivers any more in modern day Sweden. It is transported to wastewater treatment plants,” says Roxana Cremer. “Treatment removes harmful material from human wastewater before it is released to the environment. However, the treatment process can be damaged by things we put down the drain. So, in “Danger down the Drain”, we ask about what can be done to help protect wastewater treatment plants.”

Roxana Cremer, PhD student, Department of Environmental Science

John Hader, who’s doing work with the Käppala wastewater treatment association in Stockholm, was excited when he was asked to contribute to a podcast. “I’m a huge fan of science podcasts. Roxana mentioned that she had a really cool idea for a podcast where she would interview other PhD students about their research, and so I was more than happy to join when she said she needed a guest! I also really enjoy doing science communication activities, and try to jump on them whenever I get the chance,” says Hader. “Getting the opportunity to participate in a science communication activity where you only have audio adds another layer to this challenge, which was really enjoyable to work through.”

Science communication is a win-win situation

This podcast was not Cremer’s first venture into science communication. As an undergraduate student in Leipzig, she was involved in producing programs with local radio station Mephisto97.6 and even received formal science communication training sponsored by the European Geosciences Union (EGU).

“Science Communication is a part of my work that I really enjoy and finding new ways of engaging more people in science is a topic close to my heart,” she admits. “With the podcast wave starting during the pandemic, I remembered how much I enjoyed making radio back as a student in Leipzig. So, over the past year I tossed ideas around in my head about producing my own podcast,” says Roxana Cremer. Finally, this summer, she decided to record her first podcast episode when fellow student John Hader agreed to be interviewed for it. They met on Zoom, she from her bedroom at her parents’ home in Germany and he from his apartment in Stockholm. The result was “Danger down the Drain,” a 20-minute talk show-style interview about Hader’s work at Käppala, available on Spotify. In Cremer’s own words: it went better than expected!’

John Hader, PhD student, Department of Environmental Science

“We talked about a topic I would not normally choose but it was so much fun to learn about and to realise how close the topic is but an average person just doesn’t think about because it is taken care of by others. Now I want to learn more about wastewater treatment and visit a treatment plant. I also now wonder what kind of amazing interesting topics are around in my office that I just haven’t heard about yet,” says Roxana  Cremer.

According to John Hader, an opportunity such as this for any scientist is a win-win situation:

“Any time you have to sit down and think how to explain a scientific concept to people unfamiliar with it, it helps you get a different perspective of something you have been ‘in the weeds’ in for a while. I think this can be a really enriching experience and can help generate new ideas related to one’s project, so it is a win win situation.”

Cremer has not decided what the topic of the next episode will be or when she will record it because of pressing work commitments. But she says she has got “the bug” now so “stay tuned!”


About “Danger Down the Drain”


Wastewater treatment plants are crucial parts of any urban area because they help protect water bodies from human pollution and help maintain environmental water quality. Industrial facilities like car washes, airports, and hospitals use a lot of chemicals, and these chemicals can potentially be spilled down the drain in large quantities and reach the wastewater treatment plant. Microorganisms utilized in the wastewater treatment process may experience a “toxic shock” when exposed to such industrial chemicals, which can kill the microorganism community and result in the wastewater treatment process not operating properly. We have developed a method for assessing the risk posed by potential upstream industrial chemical spills, and for prioritizing chemicals that warrant additional investigation and possibly enhanced safety protocols to ensure spills don’t occur in the first place. This work will help ensure down-the-drain chemical spills do not disrupt wastewater treatment plant operations, and protect environmental water quality.

This work is done in collaboration with Marcus Frenzel from the Käppala wastewater treatment plant in Stockholm and is supervised by Professor Matthew MacLeod, Department of Environmental Science of Stockholm University. This project received funding from the EU Horizon 2020 program under Marie Skłodowska-Curie grant agreement No 813124.



Contact information

Visiting addresses:

Geovetenskapens Hus,
Svante Arrhenius väg 8, Stockholm

Arrheniuslaboratoriet, Svante Arrhenius väg 16, Stockholm (Unit for Toxicological Chemistry)

Mailing address:
Department of Environmental Science
Stockholm University
106 91 Stockholm

Press enquiries should be directed to:

Stella Papadopoulou
Science Communicator
Phone +46 (0)8 674 70 11