Wastewater has long since become a valuable resource for recycling nutrients such as phosphate or returning water to the cycle. For this, however, all pollutants such as pharmaceutical residues or corrosion protection agents must be removed from the wastewater. This is usually done with activated carbon, because the pollutants easily stick to this carbonaceous and porous material. But activated carbon is mainly obtained from lignite and hard coal. For every ton of activated carbon made from fossil raw materials, around 8.5 metric tons of CO2 equivalents are produced, which pollute the climate.

Closing carbon cycles

Researchers at the University of Kassel, in collaboration with municipal waste and wastewater management, want to investigate the extent to which biowaste is also suitable as a wastewater purifier. The SDG graduate program CirCles focuses on the production of biogenic activated carbon from potato peels, food waste or other kitchen waste. By providing and processing these biogenic residues, the inter- and transdisciplinary team aims to close urban carbon cycles.

Activated carbon from biogenic waste

Over the next three and a half years, four doctoral students will therefore use the example of Kassel to analyze which wastes and which process steps can achieve the best results. The focus will be on the targeted processing of biowaste for activated carbon production and the development of adapted pyrolysis and activation profiles for the production of high-quality biogenic activated carbons for wastewater treatment.

The project, which began in June 2022, is funded by the University of Kassel until December 2025.

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