Investigating the Effects of Aerobic Hydrolysis on Scum Layer Formation during the Anaerobic Digestion of Corn Stalk Particles

Hao Jiao, Wenzhe Li, Hongjing Jing, Ming Wang, Pengfei Li and Yong Sun
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Hao Jiao: College of Engineering, Northeast Agricultural University, Harbin 150030, China
Wenzhe Li: College of Engineering, Northeast Agricultural University, Harbin 150030, China
Hongjing Jing: College of Engineering, Northeast Agricultural University, Harbin 150030, China
Ming Wang: College of Engineering, Northeast Agricultural University, Harbin 150030, China
Pengfei Li: Heilongjiang Academy of Black Soil Conservation and Utilization, Harbin 150030, China
Yong Sun: College of Engineering, Northeast Agricultural University, Harbin 150030, China

Sustainability, 2022, vol. 14, issue 11, 1-19

Abstract: The scum layer of straw anaerobic digestion significantly impacts biogas production efficiency. The initial floating of straw after entering the reactor is an important reason for scum layer formation. Improving the settleability of straw particles and reducing the initial floating time of straw are crucial to suppressing the scum layer, and accelerating the water absorption rate of straw entering the reactor is the key to reducing the floating time. Therefore, in this study the corn stalks were kneaded and rolled, and the stalk particles were tested for water absorption and aerobic hydrolysis. The results showed that the water absorption rate of the stalks after conditioning was significantly accelerated, and the water absorption rate was 120% higher than that of the untreated stalks after absorbing water for 12 h. Simultaneously, aerobic hydrolysis destroys the lignocellulose structure to a certain extent, increases the porosity of the stalk particles, and further improves the settleability of the stalk particles. In the subsequent anaerobic digestion process, scum decreased significantly: the scum layer volume ratio was 13% lower than untreated stalks. The methane production efficiency of anaerobic digestion was significantly improved, and the optimal hydrolysis time was 12 h. At this time, the cumulative methane production of the milled treated stalks reached the maximum value of 319.64 mL/g VS, which was 26.59% higher than that of the untreated stalks.

Keywords: corn stalks; conditioning-aerobic hydrolysis; settleability; scum layer; anaerobic digestion (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2022
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