Landfill mining : a review of three decades of research

Landfills have historically been seen as the ultimate solution for storing waste at minimum cost. It is now a well-established fact however that such deposits have related implications such as long-term methane emissions, local pollution concerns and limitations on urban development. Landfill mining has been suggested as a strategy to address such resource and pollution problems and in principle means the excavation, processing, treatment and/or recycling of deposited materials. This study involves a literature review on landfill mining covering an analysis of trends, objectives and research topics in 39 papers published during the period 1988–2008. The results show that so far landfill mining has primarily been seen as a way to solve traditional waste management issues such as lack of landfill space or facilitation of final closure and remediation of waste deposits. Although most initiatives also have involved some effort to recover deposited resources (primarily cover soil material), such constituents have been largely secondary. Typically, simple soil excavation and screening equipment have therefore been applied, often demonstrating moderate performance in obtaining marketable recyclables. Several worldwide changes and recent research findings however indicate the emergence of a new perspective on landfills as future reservoirs for resource extraction. Although the potential of this approach appears gigantic, it is argued that facilitating implementation also involves a number of challenges in terms of technology innovation, concepts for realization and frameworks for evaluating economic and environmental performance.