Process combination for mechanical co-processing of residues from municipal solid waste treatment

For managing municipal solid waste (MSW), there are two different treatment methods established: thermal recovery in waste incineration (MSWI) and mechanical-biological treatment (MBT). Both generate valuable fractions and treatment residues. In the case of valuable fractions, high-calorific material from MBT is used in MSWI. Therefore, the methods are connected at the level of waste processing. However, there are differences in handling the treatment residues. Although the processing of MSWI slags for the recovery of metals and, to some extent, glass is already an established practice in countries like Austria, Germany, Switzerland, the Netherlands and Denmark, only a portion of these residues is landfilled. In contrast, MBT rotting residues are exclusively landfilled to date. This work addresses the development of a mechanical pre-treatment process aimed at separating a partial stream from MBT rotting residues. The resulting material was subsequently evaluated for its suitability for treatment using established MSWI slag processing technologies. The experiments demonstrated that this partial stream can be integrated into existing MSWI slag processing systems, enabling the recovery of metals (1 wt-%), glass (7.9 wt-%) and ceramics/stone (4.3 wt-%). In addition, a high-calorific refuse-derived fuel-feedstock comprising 5 wt-% was generated. The largest portion, accounting for 65.3 wt-%, consists of organic material that is currently being investigated as a potential feedstock for pyrolysis applications. The results show that appropriate pre-treatment can reintegrate 28.4 wt-% of the MBT rotting residues to the material cycle using existing infrastructure. This represents a connection between MSWI and MBT at the level of residue treatment for the first time.