[5-1130-P] Postharvest/Food Technology and Process Engineering (5th)

[5-1130-P-10] Anaerobic Digestion of Bean Sprouts Waste

*Yuki Yamamoto¹, Yuki Mizuya², Takaki Yamashiro³, Fetra J Andriamanohiarisoamanana^1,4, Yoshiteru Takeuchi⁵, Kazutaka Umetsu¹ (1. Graduate school of Obihiro University of Agriculture and Veterinary Medicine(Japan), 2. Obihiro University of Agriculture and Veterinary Medicine(Japan), 3. Tokachi Agri Works(Japan), 4. Graduate School of Agricultural Science, Kobe University(Japan), 5. Biomass Research(Japan))

キーワード：bean sprouts, anaerobic digestion, biogas , acid fermentation, elements addition

Wastes from food represents a critical issue globally. Bean sprouts, which are a familiar diet in Japan, are directly linked to the problem. In Ibaraki, a prefecture of japan, around 20% of the whole bean sprouts are disposed as a waste, therefore, their use as substrates for the Anaerobic digestion (AD) is of great challenge. Therefore, this study was considered to explore the potential of batch and continuous fermentation on the AD of bean sprouts wastes. In batch experiment, the biogas yields of boiled bean sprouts after 20 days were 2.4-times higher than raw bean sprouts. The continuous mesophilic experiments (38 ^oC) were conducted in three different experiments. The first experiment proposed a long period stable process after 30 days, with higher biogas yields from the mixtures of bean sprouts and return digestate than the use of bean sprout alone. The second experiment aimed to explore the impact of acid fermentation on the AD process, while the third experiment was involved the addition of trace element and different organic lading rates of bean sprouts. The results showed that acid fermentation enhanced biogas yield after 50 days by 1.5 time than no acid fermentation digester. Additionally, in third experiment, the B digester with 100g bean sprout, 200g return digestate, and 0.16g of iron, cobalt and nickel additives was produced higher organic decomposition rate of 71.02 % than the corresponding A digester (with 75g, 150g, and 0.12g, respectively) and C digesters (with 150g, 300g, and 0.24g, respectively). Therefore, the AD of bean sprouts wastes might represent a hygienic approach for their disposal with the advantage of large amounts of CH₄ production, especially when using a mixture of bean sprouts and a return digestate as a substrate. Additionally, acid fermentation, appropriate organic loading rate, and trace elements additions improved biogas production.