Feasibility of mango by-products and biogas solid residue aerobic co-composting at different C/N ratios

Abstract

Purpose: Co-composting of mango by-products and biogas solid residue eliminates some shortcomings of composting these wastes separately. Specifically, co-composing solves the problem of the low pH values in mango by-products while enhances biodegradable organic matter of biogas solid residues. However, no research report is available on co-composting of mango by-products (MB) and biogas solid residue (BR). Method: This study established three in-vessel lab-scale composting bins with 3 different C/N ratios, including Bin 1: 27.4/1 (156 kg MB + 144 kg BR); Bin 2: 30.23/1 (193 kg MB + 107 kg BR); and Bin 3: 37.7/1 (224 kg MB + 76 kg BR). The raw compost materials underwent 57 days of incubation, including 36 days of raw incubation and 21 days of mineralization. Results: Bin 3 containing larger amounts of mango by-products and less amounts of biogas residue showed a higher percentage of remaining carbon in the final products (17.97%), lower nitrogen loss (17%), and showed 0.5% increase in available P2O5 content, compared to the other bins. From 300 kg of initial raw material, the final compost mass in Bin 1, Bin 2, and Bin 3 were 26.2 kg, 32.7 kg, and 88.1 kg, respectively. Conclusion: Resultantly, an initial C/N ratio of 37.7/1 could be suggested in the aerobic co-composting of biogas residue with mango by-products. Research Highlights · Co-composting of mango by-products and biogas solid residue eliminates some of the weaknesses of composting these wastes separately. · The incubation period determined was 57 days of incubation, including 36 days of raw incubation and 21 days of mineralization. · Among three C/N ratios surveyed, the highest C/N in bin 3 (C/N=37.7/1) showed the best-favoured condition for mango by-products treatment and generate the highest amount of compost product. · Bin 3 showed the highest percentage of remaining carbon in compost products (17.97%), a lower in nitrogen loss (17%), and 0.5% increase in available P2O5 content.

Keywords

• biogas solid residue
• c/n ratio
• co-composting
• humus
• mango byproducts