Landfill mining: A review on material recovery and its utilization challenges

Landfill mining (LFM) is excavating and processing legacy waste to recover secondary resources. This study reviews the technologies used for excavation and processing of the buried waste, fractions recovered from LFM, their characterization, and environmental and safety issues associated with LFM. The study first explains the process of literature selection by which publications were selected for inclusion in the manuscript. For waste excavation, the study compiles the technologies for excavation and material processing and the safety issues involved. The fractions obtained from LFM may be divided into four broad categories: (i) soil-like material, (ii) combustible fraction (including plastic, paper, wood, and textile), (iii) inert fraction (stone, glass, ceramic, and metal) and (iv) others consisting of the remaining fraction. For material recovery, the manuscript first summarizes the percentage of various fractions obtained, the cut-off diameter for soil-like fractions, and the effect of age on various fractions recovered. The lab analyses for determining the reusability of these fractions have been explained along with the instruments required. Afterwards, the environmental and safety issues associated with LFM have been discussed. Finally, the challenges and opportunities for reutilization of materials obtained from LFM have been elaborated upon.