Legal situation and current practice of waste incineration bottom ash utilisation in Europe

Abstract

Almost 500 municipal solid waste incineration (MSWI) plants in the EU, Norway and Switzerland with a capacity of about 90.2 Mt/a, generate 17.6 Mt/a of incinerator bottom ash (IBA). This solid residue contains minerals and metals, whereas metals are mostly separated and sold to the scrap market and minerals are either disposed of in landfills or utilised in the construction sector. Since there is no uniform regulation for IBA utilisation at EU level, countries developed own rules with varying requirements for utilisation. The work at hand provides an up-to-date overview of documents regulating IBA utilisation in the investigated countries and highlights the different requirements that have to be considered. Overall, 51 different parameters for the total content and 36 different parameters for the leaching content are defined. In order to assess the leaching behaviour nine different leaching tests, including batch tests, up-flow percolation tests and one diffusion test are in place. An analysis of the weighting of each parameter relative to the totally generated IBA is expressed by a relevance level. The analysis indicates for leaching parameters average relevance levels of 36 wt.% and for total content parameters average relevance levels of 17 wt.%. This means for a significantly larger share of the entire generated IBA leaching parameters are more to be considered compared to total content parameters. A further discussion of leaching parameters showed that certain countries took over limit values initially defined for landfills for inert waste and adopted them for IBA utilisation. It was found that 18% of all defined leaching limit values for utilisation match exactly the limit values for landfills for inert waste, 19% are stricter and therefore 63% of the values are less strict than the leaching limit values for landfills for inert waste. The overall utilisation rate is approximately 53 wt.%. It is revealed that the rate of utilisation does not necessarily depend on how well regulated IBA utilisation is, but rather seems to be a result of political commitment for IBA recycling and economically interesting circumstances.