The project aims at upgrading HBI’s current innovative sewage sludge treatment system, in order to make it capable of recovering critical raw materials (CRM), by industrialising a patent owned by HBI. Thanks to the collaboration with the Free University of Bozen/Bolzano and through laboratory testing, modelling of results and design, a prototype at TRL 5 of a system for the separation of heavy metals from gasification ash will be realised, thus obtaining a fertiliser agglomerate (containing CRMs), which can be marketed as a Constituent Material Category (CMC) in accordance with Reg. (EU) 1009/2019. The successful outcome of the project will thus make it possible to approach the problem of sewage sludge treatment in a circular and sustainable way, being able to recover more than 90% of the material contained in the sludge and thus transforming an ordinary sewage treatment plant into a polygenerative biorefinery. Finally, the big advantage over competing solutions lies in the applicability of such a system even to small sewage treatment plants, while remaining cost-effective and reducing current disposal costs by between 10 and 25%.