Landfill Mining - Wet mechanical treatment of fine MSW with a wet jigger

- Through the processing of the finer material from landfills, material flows for recycling can be generated.
- The quality of the recyclables is influenced by impurities on the surface. The impurities can be removed by wet-treatment.
- Through the processing of the coarse and finer material, a reduction in volume of more than 90% is possible.

The motives for landfill mining are various. In the last couple of years Enhanced Landfill Mining (ELFM) has become increasingly important in academic discourse and practical implementation. The main goal of ELFM is to recover as much material as possible from deposited municipal solid waste (MSW). In most of the projects carried out so far, the main focus has been set on coarse materials such as plastics, woods, papers and metals. These fractions can be separated easily by sieving in combination with magnetic separation. In these projects most of the fine materials, which might represent as much as 60-70% of the total mass of the landfill body, had to be deposited again. A further treatment aiming at reducing the masses of these fine materials, which are still a conglomerate of soil, calorific fractions, metals, minerals and residues, usually did not take place. One topic in the framework of the landfill mining project TÖNSLM, in addition to the separation of the calorific fraction and metals has been the treatment of fine materials with the goal to re-use these e.g. for construction purposes. This paper shows the results obtained after the wet mechanical treatment of fine MSW 10-60 mm with a wet jigger. The physical principle of this process is the separation of the mass flux due to the different densities of the waste constituents. As a result, three main waste fluxes are obtained: Dense inert and dense fine fraction with a high content of minerals and a lightweight fraction with a high calorific value between 16 and 20 MJ/kg. An additional positive effect of wet mechanical treatment is the removal of the finest particles from the surface of the waste material, thus increasing the quality of the generated waste fluxes. The mass fluxes of the different fractions and their qualities as well as possible recovery paths are described below. An economical and ecological consideration of the treatment of the fine materials does not take place within the framework of this feasibility study.