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

Authors

• Do Thi My Phuong ¹
• Le Hoang Viet ¹
• Nguyen Thuy Duong ¹
• Nguyen Xuan Loc * ²

1. Department of Environmental Engineering, College of the Environment and Natural Resources, Can Tho University, Can Tho, Vietnam
2. Department of Environmental Science, College of the Envi-ronment and Natural Resources, Can Tho University, Vietnam

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.

Graphical Abstract

Keywords

• Biogas solid residue
• C/N ratio
• Co-composting
• Humus
• Mango byproducts