Authors: Assistant Professor Dr. M. Stephen
Abstract: Rapid urbanization, agricultural intensification and expansion of food-processing industries have resulted in increasing quantities of biodegradable organic waste. Conventional disposal methods such as open dumping and landfilling can cause nutrient losses, greenhouse-gas emissions, odour generation and contamination of soil and water. Vermicomposting offers an alternative biological technology in which earthworms and associated microorganisms convert organic residues into stabilized, nutrient-rich vermicompost. This review evaluates the quantitative evidence for vermicomposting with particular emphasis on organic-matter degradation, nutrient recovery, physicochemical stabilization, earthworm performance, agricultural benefits and environmental sustainability. Reported studies demonstrate substantial nutrient enrichment during vermicomposting. For example, vermicomposting of food-industry waste increased total nitrogen by 60–214%, available phosphorus by 35.8–69.6% and potassium by 43.7–74.1%, while organic carbon decreased by 28.4–36.1% and the C:N ratio declined by 61.2–77.8% after 15 weeks. A recent agricultural-waste study using Eisenia fetida reported a reduction in C:N ratio from 26.43 to 12.23, with the optimized treatment containing 2.63% nitrogen, 1.21% phosphorus and 1.45% potassium. Recent research further demonstrates the potential of vermicomposting to recover nutrients while reducing the environmental burden associated with organic waste disposal. The review therefore considers vermicomposting not merely as a waste-treatment process but as a nutrient-recovery, soil-restoration and circular-bioeconomy technology.
