The resources which are contained in wastes should be recovered and utilised as much as possible because of the following issues: concern about increasing global consumption of non-renewable resources, progressive shortages of primary raw materials, reduction of space available for final disposal of wastes, the need for quantity and volume reduction of wastes generated, the need for control of environmental contamination caused by emissions from waste treatment, changing social attitudes towards waste management, etc. (Cossu & Williams 2015). According to Cossu and Williams (2015), the terminology Landfill Mining represents the activities involved in extracting and processing wastes which have been previously stocked in particular kinds of deposits (municipal landfills, mine tailings, etc.).
Urban Mining extends landfill mining to the process of reclaiming compounds and elements from any kind of anthropogenic stocks, including buildings, infrastructure, industries, products (in and out of use), and environmental media receiving anthropogenic emissions. The stocked materials may represent a significant source of resources, with concentrations of elements often comparable to or exceeding natural stocks. A definition distinguishing between “stock” and “flow” resources, either anthropogenic or natural, may be necessary. Annual stocks of materials held in geological deposits, groundwater reservoirs, household and industrial buildings, infrastructure and scrap products may not vary much over time. However, annual flows of materials may change considerably from year to year, depending upon the prevailing economic situation, fashion, technical innovations, etc.
Nevertheless, from both anthropogenic stock and flow resources, secondary raw materials are produced. Resource Recovery includes the energy that can be generated by treating and managing wastes as well as materials recycling. Materials Recycling aims to transform selected wastes into materials that can be used in the manufacture of new products. Packaging waste (plastics, paper, cans, glass), putrescible, bottom ash, sewage, exhausted oils, scrap tyres, WEEE, end-of-life vehicles etc., are waste flows commonly considered as falling within material recycling strategies. The recovered materials after processing (not necessarily implying an extraction process) are reintroduced in production cycles. The extraction and processing of materials during urban mining are strongly based on economic feasibility. However, in some current material recycling strategies, political and social issues may drive recycling practices, sometimes inappropriately, either by following ideologies or by excluding technical options based on negative public opinions. Therefore, the Urban and waste mining research subtopic focuses on the technical and scientific as well as the social awareness development of materials recovery, materials recycling and resource recovery of anthropogenic stock and flow types of resources. Research is based on the existing knowledge and experience of the partner Universities as the starting point and further seeking new applications and target material streams. Recent focus areas as starting points are the followings.
The social and economic aspects of urban mining including the investigation and development of public awareness of waste management and circular economy, the growth, investment and new start-ups of the field and mapping and using of artificial intelligence for this aim. Another group of research interests is related to the material sciences, such as the applied material analytical methods (microstructure analysis) of urban mining, material and recycling technologies development from the point of view of urban mining in buildings, cars, batteries, ceramics and polymers, glass foams, municipal solid wastes, magnets and motor components, etc. Another group of research interests is related to the sampling, mapping and discovery of potential waste and landfill mining resources including municipal solid waste landfills, mine and energetic waste and by-product deposits, tailing ponds and other urban stock and flow types of resources. And the last subject area, - which is realized in cooperation with the Materials recycling research subtopic - is focused on the examination of processing techniques and technologies for producing commodity materials for downstream manufacturing.