Landfill mining is a prospective tool for the recycling of valuable materials (waste-to-material) and secondary fuel (waste-to-energy) from old, therefore more or less stabilised municipal solid waste landfills. The main target of Horizon 2020 ‘SMARTGROUND’ R&D was improving the availability and accessibility of data and information from both urban landfills and mining dumps through a set of activities to integrate all the data – from existing sources and new information retrieved with time progress – in a single EU database. Concerning urban landfills, a new sampling protocol was designed on the basis of the current Hungarian national municipal solid waste analysis standards, optimised for landfill mining. This protocol was then applied in a sampling campaign on a municipal solid waste landfill in Debrecen, Hungary. The composition and parameters of the landfilled materials were measured as a 12-year timescale. The total wet and dry mass of the valuable components possible for utilisation was estimated.

The authors are working on the development of a mechanical-physical processing plant to prepare non-selectively collected residual municipal solid waste (RMSW) in the Zalaegerszeg region of Hungary. A key element of this processing plant is the newly developed KLME separator (the name KLME is the Hungarian abbreviation of 'combined magnetic, electric and air flow'). This separator is a combination of three widely applied separators, namely a magnetic separator, an eddy current separator and two types of air flow separators designed without the ordinarily necessary cross connecting belt conveyors and feeders. Extensive RMSW and WEEE (waste electrical and electronic equipment) sampling and analyses were carried out in three municipalities to obtain model materials before designing the technology. After fundamental research and laboratory-scale testing, a pilot-scale KLME separator prototype (1.5 ton/h) was made. It has one input stream and five output streams targeted towards five types of products: two-dimensional materials (foils), three-dimensional light materials, magnetic materials, electrically conductive materials and heavy inert materials. Systematic pilot scale testing was carried out and 18 discrete technological setups were tested. The technology as well as the machine were continuously improved and modified based on on-site observations. The best yields and the experience gained are being utilised for the design of an industrial size machine.