Inga Herrmann is Associate Professor at Luleå University of Technology, Sweden, and Co-Chair of the upcoming 9th IAHR Europe Congress. Inga’s research focuses on decentralized and sustainable water and wastewater systems, with particular emphasis on on-site and small-scale wastewater treatment and source-separating sanitation systems. Her work includes low-tech and soil-based treatment systems for wastewater and greywater, management of greywater and blackwater streams, treatment and resource recovery processes, as well as systems analysis to support sustainable decision-making in the water and sanitation sector.

Interviewed by Ana Margarida Bento, Editor of Newsflash Europe

You work at Luleå University of Technology, which will host the IAHR 2026 Europe Congress. From your perspective as a researcher at the host institution, what excites you most about this event coming to northern Sweden?

I’m thrilled that the IAHR Europe Congress will bring the international hydro-environment community to the north. Luleå offers a unique perspective on water — shaped by cold climates, long distances, and close links between people and nature. Hosting the congress here highlights that sustainable water solutions must also work in remote and resource-constrained contexts, not only in large urban areas. 

Your research focuses on decentralised and sustainable sanitation systems, including constructed wetlands, filter media, and small-scale wastewater solutions. What are the most promising innovations in this area right now?

We see exciting progress in source-separating and modular systems that enable more local reuse of water, nutrients, and organic matter. Innovations in low-energy treatment technologies, such as nature-based and biofilm systems, are becoming more recognized.  

Cold climates and sparsely populated regions bring unique challenges to wastewater treatment. What insights from your research in Sweden could be useful for other regions facing similar conditions?

Only northern Sweden experiences a truly cold climate, while the southern part has a temperate climate similar to central Europe. Our research focuses on decentralised wastewater treatment and the management of greywater and blackwater. The results have global relevance, not only for Sweden or the North. At the same time, we also study decentralised treatment under northern and Arctic conditions, for example within the ArcticSewlutions project.  

Resource recovery and circular solutions are increasingly important in sanitation. What do you see as the greatest opportunities, and the biggest obstacles, for implementing these approaches in practice?

The greatest opportunity lies in recognising wastewater as a resource — rich in nutrients, water, and energy — rather than a problem to be disposed of. We now have technologies and system designs that can close local loops efficiently. Fortunately, many municipalities and organisations are becoming increasingly interested in recycling-oriented solutions. However, the main challenge remains the persistent “business-as-usual” mindset that must be overcome to achieve more sustainable wastewater management. 

You combine experimental studies with system analysis in your work. How important is it to link technical performance with social, environmental, and economic considerations when evaluating sanitation solutions?

It is crucial to identify which systems hold the greatest promise for the future by assessing their sustainability and comparing alternatives under different conditions. By combining technical experiments with system-level analyses, we can look beyond technical performance alone and gain a more holistic understanding of each solution’s potential. 

Small and decentralised systems often receive less attention than large-scale infrastructure. Why do you think it’s important that they have a strong presence in international forums like IAHR?

Decentralised systems serve the majority of the world’s population — from rural villages to peri-urban settlements — yet they are often overlooked in research and policy discussions. Including them in IAHR broadens our understanding of water management to include diversity, flexibility, and resilience. It also opens new opportunities for innovation that large, centralised systems cannot easily provide.

Early-career researchers and students often work on innovative, localised solutions. What advice would you give them as they consider sharing their work at IAHR 2026?

You are so welcome to Luleå and the IAHR conference! Be bold in demonstrating how your local insights address global challenges - and share your research with us! 

From your perspective, what kinds of collaborations, across disciplines or sectors, are most needed to advance sustainable sanitation and decentralised systems?

We need stronger bridges between engineers, social scientists, municipalities, legislators and users. Technical innovation alone isn’t enough — implementation depends on governance, behaviour, and acceptance.

The abstract submission deadline for IAHR 2026 is approaching. What message would you like to share with colleagues working in sanitation, wastewater treatment, or water reuse to encourage them to submit their work?

This conference is a rare opportunity to present sanitation research within the broader hydro-environment community and to connect with experts in hydraulics, hydrology, and Urban Water Engineering. We especially welcome all sanitation contributions! 

Finally, what legacy would you like IAHR 2026 to leave both for the global water community and for the local research environment here at LTU?

For LTU, it’s a chance to strengthen our collaborations and attract new talent to sustainable water research. More broadly, I’d like the congress to leave a legacy of inclusion — that water engineering embraces diversity in climate, context, and community. 

Related 

9th IAHR Europe Congress "Innovating Hydro-EnvironmentEngineering for a sustainable future. Artic Waters and Beyond" 09 - 12 June 2026, Lulea, Sweden 

IAHR Europe Division