Valuable parts of bottom ash, which is the residue from the combustion of household waste, can be recycled. The combustion process cleans and separates metals and inerts from mixed waste, which could not otherwise be recycled. As a result further recycling of these metals is possible. 

For example, the remaining ferrous and non-ferrous metals in the waste can be extracted from the bottom ashes and recycled into new products such as aluminium castings for the automotive industry. Other remaining minerals can be used as secondary aggregates, e.g. in road construction or in building products.

Due to the extra quantities of materials recovered from bottom ash Waste-to-Energy Plants contribute further to achieving a recycling society and thus help to improve Europe’s resource efficiency, using unavoidable waste as a valuable resource wherever possible.

For further information:
CEWEP paper on the Environmentally sound use of bottom ash

CEWEP Article in Waste Management World Magazine 2011 "Rising from the Waste to Energy Ashes"

CEWEP/EAA Seminar 5-6 Septmber 2011 “From ashes to metals - Bottom ash from Waste-to-Energy plants as a material resource”, Copenhagen