Energy-from-Waste plants using grate-based systems have gained world-wide acceptance as the preferred method for the sustainable treatment of waste. Key factors are not only the reduction of waste volume and mass and the destruction or separation of pollutants but also the efficient production and use of energy (electricity, district heating/cooling, process steam), compliant disposal and the recovery of resources from combustion residues (e.g. metals, rare earths). International requirements relating to energy efficiency and materials recovery by means of thermo-recycling in Energy-from-Waste plants call for the continuing development and optimization of existing technologies and concepts.
The technologies and processes for the recovery of reusable materials from dry-discharged bottom ash and from filter ash point to the key role that Energy-from-Waste plants are able to play in the efficient conservation of resources. It is primarily thermal treatment with dry discharge and subsequent processing of the bottom ash fractions that enables Energy-from-Waste plants to justify their status as universal recyclers. In addition to recovery of the energy inherent in the waste, the treatment of dry-discharged bottom ash is an important contribution to compliance with raw material and climate policies and to the promotion of closing the material cycle in general. Furthermore, dry bottom ash discharge represents a further step towards waste-free operation and “after-care-free” landfills.
This paper documents the potential of Energy-from-Waste plants for the recovery of resources and provides examples of recent developments and large-scale implementations of innovative recovery technologies in Europe.