Earthworm mediated amelioration of heavy metals from solid organic waste: an ecotechnological approach toward valorization

Landfilling accounts for 70% of solid waste disposal in developing nations such as India. The leaching of heavy metals from such solid organic waste contaminates the top soil and food chain. Several earlier research studies have demonstrated the importance of various waste management systems in countering the heavy metal load from such organic sludges. However, very few steps have been taken towards profitable bioremediation of heavy metals from organic contaminants. The present research review has unearthed the potential of earthworms towards the amelioration of heavy metal load. Earthworms, being an ecosystem engineer, engage in interactions with toxic sludge material and facilitate valorization of organic contaminants through microbial interactions. Vermicomposting has emerged as a leading-edge technology in form of cost-effective and energy-intensive approach in solid waste management. However, several other methods like phytoremediation involving plants and microbial remediation utilizing bacteria, fungus, yeast etc. have been found to be efficient in reducing the mobilization of heavy metals. The present study has comprehensively investigated the importance of earthworm, vermicomposting, and bioremediation in comparison to several conventional technologies toward the effective valorization of organic contaminant.