Effort to Mitigate Volatile Fatty Acid Inhibition by Using Mixed Inoculum and Compost for the Degradation of Food Waste and the Production of Biogas

Lai Llih Shyan, Noreen Suliani Mat Nanyan, Norli Ismail (), Adel Al-Gheethi (), Hong-Ha T. Nguyen, Dai-Viet N. Vo and Hesham Ali El Enshasy
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Lai Llih Shyan: School of Industrial Technology, Universiti Sains Malaysia (USM), George Town 11800, Malaysia
Noreen Suliani Mat Nanyan: School of Industrial Technology, Universiti Sains Malaysia (USM), George Town 11800, Malaysia
Norli Ismail: School of Industrial Technology, Universiti Sains Malaysia (USM), George Town 11800, Malaysia
Adel Al-Gheethi: Renewable Biomass Transformation Cluster, School of Industrial Technology, Universiti Sains Malaysia (USM), George Town 11800, Malaysia
Hong-Ha T. Nguyen: Institute of Applied Technology and Sustainable Development, Nguyen Tat Thanh University, Ho Chi Minh City 755414, Vietnam
Dai-Viet N. Vo: Center of Excellence for Green Energy and Environmental Nanomaterials (CE@GrEEN), Nguyen Tat Thanh University, 300A Nguyen Tat Thanh, District 4, Ho Chi Minh City 755414, Vietnam
Hesham Ali El Enshasy: Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia (UTM), Skudai 81310, Malaysia

Sustainability, 2023, vol. 15, issue 2, 1-15

Abstract: Food waste is a rich organic matter that can potentially be converted into biogas as a source of renewable energy. The limitation in energy production lies in the presence of volatile fatty acid (VFA) during the anaerobic digestion of food waste due to the high degradation rate. The accumulation of VFA leads to a decrease in pH that exceeds the optimal pH range of 6.8–7.6 for methanogens, thus inhibiting methanogenesis and affecting biogas production. In the present study, a symbiotic culture of bacteria and yeast (SCOBY) and kombucha mixed inoculum and compost was applied as an alternative treatment method to alleviate inhibition. The digestion efficiency was evaluated on pH, total alkalinity (TA), total volatile fatty acid (TVFA), total solid (TS), and volatile solid (VS) throughout the digestion period of 80 days to analyse the stability of the system. The results revealed that SCOBY and kombucha mixed inoculum caused system instability, inducing inhibition at TVFA of 12,874.1 mg/L, while the pH dropped to 5.23. The inhibition in the digestion system with only the SCOBY inoculum occurred at TVFA of 11,908.3 mg/L, and the pH dropped to 5.67. The biogas and methane yield quantified from the mixed inoculum is 8.792E −4 L/L d, comparatively lower than the ethanol pre-fermentation treatment method. These findings indicate that the addition of compost improved the pH, VS, and TVFA.

Keywords: biogas; food wastes; factor; volatile fatty acid; compositing (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2023
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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