Environmental impact evaluation of landfill mining of legacy waste with on-site sorting using life cycle assessment

The present research is aimed at assessing the environmental impacts of landfill mining of soil-like material with on-site sorting for land application using life cycle assessment. The scenario is compared with no-landfill mining (base scenario) and future scenario (including material recycling and incineration). Soil-like material is processed using windrow composting. The impact assessment was performed using the EASETECH™ software tool. ReCipE 2016 midpoint world impact method with eight impact categories was used for assessing the environmental profiles. The functional unit of the assessment was 1 t of recovered waste in India. Overall, the results showed that excavation of landfilled waste with on-site recovery of soil and land application of soil resulted in higher environmental benefits compared to no mining condition in global warming potential (GWP), freshwater eutrophication (FEW), human toxicity (HT), and fossil depletion (FD), while higher impacts were observed in terrestrial acidification (TA), terrestrial ecotoxicity (TE), marine eutrophication (ME), and photochemical oxidation (PCO). After composting, land application of recovered soil contributed to environmental offsets in GWP, HT, and FEW while contributing to TE emissions. Emissions associated with excavation and on-site sorting contributed 55.1% to freshwater toxicity, 25.5% to human toxicity, 16.2% to climate change, and 10.8% to terrestrial acidification. The choice of energy, transportation, and fuel for waste activities affected the performance of alternative scenarios in GWP. Application of recovered metals in the manufacturing process, incineration of plastic, and textile components improved the environmental performance. The outcomes of this research will equip regulatory bodies in the development of guidelines and frameworks on material and energy recovery from the waste components mined from legacy waste.