Infusion of fruit-vegetable waste biomass into bakery sludge to enhance nutrient availability and vermicompost maturity using Eisenia fetida

Vermicomposting of bakery sludge (BS) was studied when amended with fruit-vegetable waste (FV) and cow dung (CD) with different proportions in vermi-units (VU): VU1(CD100), VU2(CD75BS25), VU3(CD50BS25FV25), VU4(CD25BS25FV50), and VU5(CD25 BS50FV25). Results showed a reduction in pH and total organic carbon and an increase in electrical conductivity, ash content, nitrogen, phosphorus, and potassium after vermicomposting. Carbon/nitrogen decrease followed: VU3 > VU1 > VU4 > VU2 > VU5, whereas a maximum reduction in carbon/phosphorus (60.7%) was observed in VU3 and a minimum (44.8%) in VU5. Seed germination assay of Cicer arietinumwas 71–138% with maximum in VU3. Respiration rates of 69–115 mgCO2kg−1VC48h−1were achieved signifying stability and non-toxic impact. The presence of FV waste in vermi-units enhanced earthworm population, biomass, growth rate, and cocoons. VU3 exhibited higher macro- and micronutrients as well as worm growth and fecundity over other vermi-units. Based on results, FV waste and CD amendment at 25% and 50%, respectively, are suggested as appropriate to produce enriched vermicompost from BS using Eisenia fetida.