Keywords: municipal solid waste, MSW, organic solid waste, vegetable market waste, floral waste, earthworm species, vermiculture, composting, cadmium, lead, zinc, copper, manganese, waste management, earthworms, heavy metals, vermicomposting
Remediation of heavy metals from urban waste by vermicomposting using earthworms: Eudrilus eugeniae, Eisenia fetida and Perionyx excavatus
This study revealed that three earthworm species, viz., Eudrilus eugeniae, Eisenia fetida and Perionyx excavatus, through vermicomposting remediated heavy metals - Pb, Zn, Cd, Cu and Mn from the urban waste - organic fraction of Municipal Solid Waste [M(O)SW], vegetable Market Waste (MW) and Floral Waste (FW). The concentrations of Zn, Cd and Cu were 36.1, 50.9 and 70.2% higher in M(O)SW compared with that of MW, while the concentrations of Pb and Mn were 96.5% and 80.1% higher in MW than that of M(O)SW, respectively. Of the vermicomposts and the composts of the wastes, FW and its vermicompost possessed lower concentrations of the Cd, Pb, Zn, Cu and Mn by 72.2, 55.7, 73.6, 78.2 and 48.2% and 58.0, 77.4, 64.1, 63.0 and 71.2% compared with that of M(O)SW and MW, respectively. The concentrations of these metals were significantly lowered in the vermicompost produced by the earthworm species compared to that of the respective substrates. Their concentrations showed significant decrease across different time intervals during vermicomposting process. The removal efficiency of the heavy metals was more in the vermicompost produced by E. eugeniae than that of E. fetida and P. excavatus, and the compost (P < 0.05).