Application of unsegregated municipal solid waste char produced at low temperature and vermicompost for remediation of coal mine tailing soil.

The melioration of mine tailing soil (MTS) with unsegregated municipal solid waste (MSW) char and vermicompost (VC) significantly improved soil properties. The novelty of this research lies in utilizing MSW char derived directly from landfill waste, combined with VC, to enhance soil properties while mitigating heavy metal toxicity. Results indicate that 10% MSW char increased soil pH by 45.44% and specific gravity by 4%, while a 5% char and 30% VC mix improved volatile solids, electrical conductivity, water holding capacity, and total Kjeldahl nitrogen by 2.45, 1.76, 2.96, and 2.79 fold, respectively, with a 3.3% reduction in bulk density. Heavy metal immobilization was significant, with total Fe, Ni, and Pb reducing by 28%, 22%, and 9%, respectively. Bioavailable Fe decreased by 89% with 20% char, while Ni and Pb bioavailability dropped to undetectable levels. Metal leachability was minimized, reducing Ni and Pb by 30% and 61%, respectively. These findings highlight the effectiveness of MSW char and VC in improving MTS properties, enhancing nutrient retention, and mitigating heavy metal risks, offering a sustainable approach for mine land restoration.