10 December 2024

Completion of the CarboMass project

The closing event of the CarboMass project in the Kulturhaus Bleicherode was ceremoniously opened with warm words of welcome from Prof. Dr Wesselak, Vice President for Research and Development at Nordhausen University of Applied Sciences, Mr Schimm, the second deputy of the district of Nordhausen, who spoke on behalf of the district administrator Mr Jendricke, and Mr Strauß from the project sponsor Jülich.

The event marked a significant milestone for the successful CarboMass project, which was characterised by the commitment of a strong consortium of six regional and national partners: the rural municipality of Bleicherode, the Bode-Wipper wastewater association, the Südharz water association, the district of Nordhausen, IMM GmbH & Co. KG and Nordhausen University of Applied Sciences as the coordinating institution.

Around 30 participants listened to the inspiring acceptance speeches. The speeches and the presentation of engineering and administrative research results, presented by the project leaders Prof Dr Uta Breuer and Prof Dr Elmar Hinz, underlined the far-reaching significance of the project for the Nordhausen region and beyond.

The CarboMass project is investigating the use of pyrolysed sewage sludge as a possible component for covering potash residue stockpiles. In July 2021, research began at a laboratory facility at the Thuringian Innovation Centre for Recyclable Materials and planting trials were analysed in Mitscherlich vessels. The highlight of this project was the commissioning of the pilot pyrolysis plant and the equipping of the test areas on the premises of the Bode-Wipper wastewater association in August 2023.

Thanks to a project extension until the end of 2024, the planting and sampling of the test areas at the potash tailings pile of IMM GmbH & Co. KG in Sollstedt could also take place. The scientifically supervised testing shows that the findings obtained on a laboratory scale cannot be transferred one-to-one to the pilot plant - different conditions, circumstances and also sewage sludge lead to varying parameters. The development of a business model is also complex, as the individual sewage treatment plants and their supporting organisations as well as the processed sewage sludge exhibit a high degree of regional diversity. This makes it difficult to scale the pilot operation to the whole of Germany.

The analyses of the planting trials on the various test areas show that vegetation has a positive effect on compliance with the limits set by mining law. These results illustrate the potential of pyrolysed sewage sludge as a component of the covering material for potash tailings piles. However, unclear regulatory framework conditions and unclear long-term financing of novel approaches in the circular economy continue to pose a challenge for municipalities when trialling innovative approaches and transferring them to regular operations.

Nevertheless, this project brings the sustainable utilisation of sewage sludge within reach: For example, Mr Strauß conveyed a big thank you for the valuable knowledge gained from the project, which has since been integrated into a legislative initiative. If it is possible to achieve regulatory adjustments or even a joint rethink in the implementation of the circular economy, CarboMass could be a beacon for a sustainable and regional circular economy in the field of sewage sludge utilisation.

We would like to express our sincere thanks to all participants at the closing event and to the numerous stakeholders who have accompanied and significantly shaped the CarboMass project along the way for their valuable suggestions and contributions.