Harnessing Eisenia fetida for the vermconversion of biodegradable wastes in Dambi Dollo town, Ethiopia.

Abstract

Vermicomposting is a sustainable bioconversion process in which earthworms transform organic residues into nutrient-rich bio fertilizers under mesophilic conditions, with pH and moisture critically influencing decomposition efficiency. While microbial activity initiates substrate breakdown, Eisenia fetida plays a central role in stabilizing organic matter and enhancing nutrient content. This study investigated the performance of E. fetida in the 60-day vermicomposting of three locally available biodegradable wastes coffee husk, paper waste, and vegetable residues in Dambi Dollo town, at Dambi Dollo University Research center, Ethiopia. Coffee husk and paper waste were mixed with cow dung (3:1 ratio), whereas vegetable residues were composted without cow dung. Thirty mature worms were introduced per treatment, and samples were analyzed at Days 0, 30, and 60 for physicochemical and biological parameters. The results revealed significant transformations in substrate quality, including pH (7.51-7.03), EC (1.91-1.24 mS/cm), organic matter (47.06-29.21%), organic carbon (27.3-16.93%), total nitrogen (1.38-2.19%), C: N ratio (21.39-8.63), available phosphorus (11.17-20.85 ppm), and exchangeable potassium (2.26-4.43 mg/kg). The final vermicompost was well-stabilized, nutritionally enriched, and compliant with WHO and ISIRI standards. This study demonstrates the potential of vermicomposting as a cost-effective, environmentally sustainable, and locally adaptable solution for managing biodegradable waste, providing high-quality organic fertilizers for agricultural use. These findings offer insights applicable to similar tropical and subtropical African regions, emphasizing the role of vermiculture in promoting circular economy and sustainable agriculture.