Integration of resource recovery into current waste management through (Enhanced) landfill mining

Abstract

Europe has somewhere between 150,000 and 500,000 landfill sites, with an estimat-ed 90% of them being “non-sanitary” landfills, predating the EU Landfill Directive of 1999/31/EC. These older landfills tend to be filled with municipal solid waste and often lack any environmental protection technology. “Doing nothing”, state-of-the-art aftercare or remediating them depends largely on technical, societal and eco-nomic conditions which vary between countries. Beside “doing nothing” and land-fill aftercare, there are different scenarios in landfill mining, from re-landfilling the waste into “sanitary landfills” to seizing the opportunity for a combined resource-re-covery and remediation strategy. This review article addresses present and future issues and potential opportunities for landfill mining as an embedded strategy in current waste management systems through a multi-disciplinary approach. In par-ticular, three general landfill mining strategies are addressed with varying extents of resource recovery. These are discussed in relation to the main targets of land-fill mining: (i) reduction of the landfill volume (technical), (ii) reduction of risks and impacts (environmental) and (iii) increase in resource recovery and overall profit-ability (economic). Geophysical methods could be used to determine the charac-teristics of the landfilled waste and subsurface structures without the need of an invasive exploration, which could greatly reduce exploration costs and time, as well as be useful to develop a procedure to either discard or select the most ap-propriate sites for (E)LFM. Material and energy recovery from landfilled waste can be achieved through mechanical processing coupled with thermochemical valori-zation technologies and residues upcycling techniques. Gasification could enable the upcycling of residues after thermal treatment into a new range of eco-friendly construction materials based on inorganic polymers and glass-ceramics. The mul-ti-criteria assessment is directly influenced by waste- and technology related fac-tors, which together with site-specific conditions, market and regulatory aspects, influence the environmental, economic and societal impacts of (E)LFM projects.