Leather Industries Solid Waste Conversion to Organic Fertilizer through Vermicomposting: Utilization for Plant Growth

Abstract The generation of leather industries' solid waste is a matter of concern in the present world for its potential polluting ability. This study has assessed intend vermicomposting of leather industries generated lime flesh and shaving waste through a mix with cattle dung using Eisenia fetida earthworm, aiming at sustainable reuse in agriculture. The chromium content of shaving waste was optimized and brought under 2 mg/kg using hydrogen peroxide with potassium carbonate treatment and lime flesh was treated with hydrochloric acid treatment. Treated shaving waste and lime flesh were mixed with cattle dung in a proportion portion of 1:1 and 2:1 in different vermicompost fields. After 30 days 40 Eisenia fetida were introduced in each field and vermicomposted for 90 days within 50% of moisture was maintained. The number of earthworms was observed notably increases in every bed of 1:1 portion of vermicompost and a higher 2:1 portion of waste remarkably attacked the growth of worms. The parameters of this study were analyses and the number of earthworms, pH, total organic carbon (TOC), total Kjeldahl nitrogen (TKN), carbon and nitrogen ratio (C: N), total potassium (TK) and total phosphorus (TP) readings were taken at 0, 30, 60 and 90 days respectively. The resulting composting in a substantial reduction of pH, TOC and the C: N ratio was notably decreased by approximately nine-fold and increases in TKN and TP were seen. A slight reduction of TK was also observed. The results show that the earthworm Eisenia fetida has been able to convert the lime flesh and shaving waste into nutrient-enriched fertilizer products in the same proportion of waste and cow dung. However, the resultant vermicompost was applied on the Napier grass plantation. The accumulation of heavy metal effect on plants was investigated systemically for eco-friendly plant growth. The composts and plants’ different parts were analyzed for heavy metals and those found under permissible limits recommended by WHO. It was found vermicompost enhanced the organic matter significantly and nutrients are also improved for better crop yield.