In the summer of 2002, an experimental wet process was tested on 116 tons of bottom ash from the Amsterdam MSWI. The aim of the pilot was to demonstrate the feasibility of combining a washing step for improving the environmental quality of the ash with extensive metals recovery to meet the cost of the treatment. Bottom ashes from the incineration of household waste can be re-used as a building material for the foundation of roads, provided that the material does not leach contaminants, such as copper, to the environment. Washing the ash in the same way that contaminated soil is treated in soil remediation plants solves the leaching problem. The increased value of the building material and the non-ferrous metals extracted from it pay for the wet process.
