• Parrodi, Juan Carlos Hernandez
• Vollprecht, Daniel
• Pomberger, Roland

Abstract

Multiple landfill mining investigations of municipal solid waste landfills have been carried out worldwide in the past decades. Some of these studies have led to the conclusion that landfill mining is not feasible and could represent more of a problem than a solution for old landfill sites. This is the case to a certain extent because, to this day, material and energy recovery in landfill mining has been restricted to the coarse fractions (>10 mm to >60 mm) in most projects, while the fine fractions (<10 mm to <60 mm) have been often re-directed to the landfill with poor or no treatment at all despite their recovery potential. The fine fractions account for 40-80 wt.% of the total amount of the landfill-mined material. Its material composition is characterized by about 40-80 wt.% decomposed organic matter or weathered mineral fractions which cannot be hand-sorted, followed by significant amounts of calorific fractions and a small amount of metals. The main chemical compound found in landfill mining fine fractions is SiO2, mostly present as quartz and minor amounts of sheet silicates, followed by CaO, mostly present in carbonate minerals. MgO, Fe2O3 and Al2O3 represent minor components. Heavy metals are present in concentrations of few to several hundreds of mg/kg without a clear general trend of enrichment compared to the coarse fractions. In contrast, the net calorific value of the fine fractions (about 3-9 MJ/kg DM) can be several times lower than that of the coarse fractions (about 10-30 MJ/kg DM). These data clearly indicate that both a mineral fraction for waste-to-material and a calorific fraction for waste-to-energy might be recovered if suitable mechanical processing technologies can be employed. The potential of the fine fractions for material and energy recovery, as well as the main technological challenges to unlock it, are the main topics discussed in the present review article. This article has been elaborated within the framework of the EU Training Network for Resource Recovery through Enhanced Landfill Mining – NEW-MINE.​

Topics

• impedance spectroscopy
• mineral
• compound