The project at the AVA cleanphos pilot plant is being put to the test by AVA-CO2 Forschung GmbH in Karlsruhe in partnership with the University of Hohenheim and the Project Group Materials Recycling and Resource Strategies IWKS at the Fraunhofer Institute. According to Zug-based biotechnology company AVA-CO2, the aim is to show that cleanphos technology can recover phosphorus for use in fertilisation from sewage sludge.
The HTC process, which transforms the sludge into carbon and extracts the phosphorus, is more efficient and cheaper than existing techniques – and it offers new possibilities in agriculture. Professor Andrea Kruse from the University of Hohenheim explained that although sludge contains a lot of valuable phosphorus, there is much going against its use in agriculture. For example, it can carry pathogens and it contains lots of heavy metals.
So far, phosphorus has mainly come from China, the USA and Morocco. However, these mineral plants have been overused and now need to be extended even deeper. Yet the deeper the drill goes, the more the phosphorous is fortified with heavy metals like uranium – which will end up in the fields again. According to Professor Kruse, we need new sources of phosphorus. She underlined that sewage sludge was one of them, and that it could be used via the HTC-based AVA cleanphos technology.