Co-digestion of peach biowaste and parboiled rice effluent: Characterization of feedstocks and renewable energy possibility

Abstract

The co-digestion of a peach biowaste and parboiled rice effluent mixed with a sludge digester was investigated using a lab-scale biodigester. The biomasses used in the system were characterized by physical-chemical and microbiological analyses. Variations in substrate/inoculum (S/I) ratio of 1:1, 1:2, and 3:2, with different percentages of peach bagasse of 0%, 5%, and 10% in the substrate combination (peach bagasse + effluent), were performed. The study found that co-digestion of peach bagasse and parboiled rice effluent with digester sludge resulted in higher biomethane production, with reactors II and IV showing the best combination of factors both with a proportion of 3:2 (S/I). Reactor IV showed the maximum production of 27.51 mL CH4 with a substrate composition of 10% peach bagasse and 90% effluent. The physical-chemical properties of the co-digestion substrate were optimal for anaerobic digestion, and the microbial community adapted to enhance biodegradation. The maximum COD removal was found in reactor IV at 88.06%, followed by reactor V at 82.10%. In contrast, the 1:2 (S/I) ratio in reactor I showed the lowest methane production. Furthermore, the co-digestion process resulted in stable and efficient digestion, indicating it is a viable alternative for treating rice parboiling effluent and peach waste.