STRABAG has acquired a 50.65% stake in Ökologische Klärschlammtrocknung Offenhausen GmbH (ÖKT), expanding its portfolio of sustainable building materials into technical carbon.
ÖKT operates an integrated pyrolysis and sewage sludge drying plant in Offenhausen, Bavaria. The facility processes biomass and biogenic residues from forestry and agriculture – including forest wood chips and corn cobs – converting them into certified biochar under the European Biochar Certificate standard.
The pyrolysis process generates waste heat, which is used to dry both the input material and sewage sludge, with the latter subsequently used as a low-emission fuel.
STRABAG intends to use biochar for the long-term binding of CO2 in building materials such as concrete and asphalt, where it can also act as a permanent carbon storage medium. The company said biochar has the potential to improve the material properties of concrete. It is also being used in agriculture and in substrates for urban greening projects, owing to its water and nutrient retention properties.
ÖKT was founded in 2019 as a spin-off from a farm in Bavaria. STRABAG has had a dedicated unit working on renewable and mineral raw materials, technical carbon, and CO2-reduced concrete for the past two years.
Andreas Ertel, managing director of ÖKT, said: “The use of technical carbon opens up new avenues for the construction industry to reduce emissions. We are very much looking forward to working with STRABAG and see this as an excellent basis for jointly developing this future-oriented topic.”
Herwig Sumetzberger, head of technical directorate sustainable building materials at STRABAG, said: “Biochar is a concrete lever for implementing our sustainability strategy and the Strategy 2030. It contributes to reducing CO2 emissions in building materials while simultaneously expanding our own production of sustainable materials. The combined resources and expertise enable us to further develop the potential of biochar in a targeted manner and scale it operationally along our value chain.”
Main image: STRABAG is participating in the ecological sewage sludge drying project in Offenhausen. Credit: © STRABAG/Jakob Strzalowski
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