Landfill mining – reclamation of landfills

© Astrid Gast/Fotolia

Until 2005, household waste was generally sent directly to landfill sites, and for long periods of time in which there was no closed loop recycling as we know it by today’s standards. It can therefore be assumed that landfill sites contain valuable materials such as metals and plastics, and that these materials can be processed into fuels or mineral building materials. This comprehensive research project examined the extent to which this potential can be exploited, and which technology and recovery strategy can be used. The project was accompanied by a field trial and the reclamation of 10,000 tonnes of material from the Pohlsche Heide landfill site.

Several complex treatment strategies were developed and tested in various field trials conducted in conjunction with the project partners. The material recycling of waste components (in particular plastics) proved to be difficult, primarily due to the very high proportion of fine materials and cross-contamination. From an ecological viewpoint, landfill mining proved to be feasible if the thermal utilisation of the parts with a high calorific value can take place in highly energy-efficient systems. Recovering the metals as comprehensively as possible proved to be feasible, even if it involves considerable effort. The findings were evaluated and recorded in the form of a guide to help landfill operators to reach a decision on reclaiming landfill sites.

ifeu’s role in the project

ifeu Heidelberg, supported by the Öko-Institut, was responsible for the accompanying ecological research. This ensured that high ecological standards were applied to the reclamation. However, the accompanying research primarily served to achieve the most high-quality use of the valuable waste components, while ensuring a good balance between effort and benefit. During the project, the various potential strategies for treatment and utilisation of the landfill site were also analysed and evaluated in the form of LCAs.