Professor Chao He aims to share his holistic vision of sustainable waste recovery with the world

What are your main research interests?

I focus on developing sustainable technologies that transform waste and side streams, including wastewater, sewage sludge, digestate, plastics and biomass residues, into cleaner energy, high-purity nutrients, valuable chemicals and reusable materials.

My research on the hydrothermal treatment of sewage sludge began in 2009. My work takes a multidisciplinary approach with an emphasis on the circular economy. I examine research topics from the perspectives of fundamental science, reaction processes, industrial applications and commercialisation.

Developing these technologies requires teamwork. Together with my Circular Economy Innovation (CEI) research group, which I founded in 2021, we convert wastewater sludge into valuable products by removing pollutants and recovering nutrients, such as phosphorus and nitrogen. The remaining carbon material is then transformed into cleaner fuels and gases that can be used to produce sustainable chemicals and biofuels. The CEI group also collaborates with other researchers in energy, environmental engineering and chemistry, both within and outside Tampere University.

What makes your research significant?

Waste is often viewed as a problem, but my research shows that it can be part of the solution within a circular economy. By converting waste into sustainable energy, valuable nutrients and materials, my work helps to reduce environmental impacts, decrease dependence on fossil resources, and provide relevant industries with the technological foundations required for the transition to a circular economy.

One Nordic company is already building a pilot plant to apply this technology in the treatment of sewage sludge generated by the pulp and paper industry.

How do you intend to develop your research field in the future?

To advance my research, I am pursuing a three-pillar approach: scaling up infrastructure, strengthening global collaboration, and integrating research with education. 

First, on the engineering side, I am actively moving my research from fundamental laboratory-scale validation towards continuous pilot-scale applications. My next step is to lead the design and construction of a new, advanced fluidised-bed apparatus. This platform will be critical for testing our catalytic and thermal processes under realistic and dynamic industrial conditions.

Second, I plan to leverage my editorial roles, such as my position with the Journal of Environmental Chemical Engineering, and my international network to build cross-border consortia, so that we can work together to address global waste challenges. 

Finally, as Head of Specialisation in Environmental Engineering in the Science and Engineering BSc Degree Programme at Tampere University, I aim to integrate these cutting-edge circular economy technologies directly into the curriculum and train the next generation of environmental engineers to continue driving the transition to a circular economy.

What would you want to research next and why?

I will continue to develop thermochemical conversion technologies, but I also want to explore the technical and economic aspects of commercialising circular economy innovations.

I believe technology can contribute to a sustainable society only if it survives the commercialisation process and is widely adopted. I want to examine how our technologies can be integrated into existing heavy industrial infrastructure in economically viable ways. My goal is to combine rigorous environmental technology with sound and long-term commercial viability. If we can demonstrate both the scientific elegance and economic viability of these systems, we can bring about real, systemic change.

Photo: Jonne Renvall, Tampere University

Where do you draw inspiration for your work as a professor?

I draw inspiration from three distinct sources. The first is the global scientific community. I gain new ideas by following international journals, reading scientific reviews and attending academic conferences.

The second is engineering practice. Visiting international institutions, collecting blueprints and building new equipment in our laboratory are all highly motivating.

The third is interdisciplinary thinking. I draw on broader ways of thinking, particularly the principles of rational decision-making and resilience, to ensure that my research strategy focuses on long-term value rather than short-term academic trends.

Together, these sources keep me energised in the long-term pursuit of a circular economy.

What do you do in your free time?

Sometimes my mind gets bogged down in work-related matters. To maintain balance, I spend time with my family and play card games and ball games with my son, who is particularly fond of football. Spending time in nature provides a great opportunity to relax, recharge, gather new strength and learn through curiosity. For me, Finland is a good place both to raise a family and to do business.