A valorisation approach in recycling of organic wastes using low-grade rock minerals and microbial culture through vermicomposting

Abstract

A study was steered to explore the effect of rock mineral addition (i.e., rock phosphate (RP), dolomite (DM) and mica (MC)) in organic wastes (e.g., water hyacinth and paddy straw) along with microbial inoculums on vermicompost quality. Different amalgamations of four microbial inoculums viz., Trichoderma viride, Azotobacter chroococcum, Bacillus polymixa and Bacillus firmus, and three rock minerals i.e., RP, DM, and MC were used during vermicomposting process to access their effect on the quality of mature vermicompost. A significant reduction in pH, organic carbon, C/N ratio, while significant increase in humic acid, total nitrogen, available phosphorus and exchangeable potassium was observed in each of the vermibeds. Furthermore, enzymatic activities were also boosted considerably due to Vermi-stabilization. Application of rock minerals at 10% (200 g in 2 kg organic waste mixture) along with microbial inoculants in the vermicomposting process promoted the availability of macronutrients as compared to control treatment. The results showed that the combination of rock minerals and microorganisms along with earthworms facilitated the decomposition and reduced the overall time required for composting besides producing a nutrient-enriched vermicompost product.

Keywords

• Organic wastes
• Rock minerals
• Microorganisms
• Enriched vermicompost