A. YADAV;V. K. GARG

Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar 125001 (India)

eisenia fetida;food industry sludge;heavy metals;manure;vermicompost

Vermicomposting is a biotechnological process that enables the recycling of organic waste materials into manure through the combined action of earthworms and mesophilic microorganisms. In this study, a 13-week experiment was carried to vermiprocess food industry sludge mixed with different bedding materials including two weeds, water hyacinth and parthenium, as well as cow dung, in different combinations employing earthworms of the species Eisenia fetida. Eight vermibins containing one kilogram of the waste mixtures (dry weight basis) were established for vermicomposting. Vermiprocessing significantly increased nitrogen, phosphorous, and potassium contents of the mixtures. However, a decrease in pH, organic carbon, and C:N ratio was observed after vermiprocessing. The heavy metal contents in the vermicomposts were higher than the initial values but within permissible limits. These results indicated that the studied wastes can be converted into good quality manure by vermiprocessing, which indicatedtheir agricultural values as a soil conditioner if mixed with weeds in appropriate ratios.