Effect of full reflux of biogas slurry on biogas production with agricultural wastes
CHEN Guang-yin1,2, WANG En-hui2, ZHENG Jia-wei2, WU Pei2, LIU Xu2, FANG Cai-xia1,2
1. Anhui Engineering Laboratory of Soil and Water Pollution Control and Remediation, Wuhu 241002, China; 2. School of Ecology and Environment, Anhui Normal University, Wuhu 241002, China
Abstract：To realize the reduction of biogas slurry from the source, the feasibility of full reflux of biogas slurry for biogas production with agricultural wastes was studied at a CSTR reactor. The results showed that, the pH value and EC of the biogas slurry increased continuously, the total nitrogen (TN) content decreased to a low level (only 110mg/L on day 132) during the anaerobic mono-digestion of rice straw, and the content of total volatile fatty acids (TVFAs) accumulated gradually after day 94. Meanwhile, the daily biogas yield decreased gradually, and which was only 50% of that in the stable biogas production period on day 104. Insufficient nitrogen is an important reason for the decrease in the daily biogas yield during the anaerobic mono-digestion of rice straw with full reflux of biogas slurry. The daily biogas yield increased rapidly after nitrogen supplement and was 1.5times higher than that before nitrogen supplementation. Compared to anaerobic mono-digestion of rice straw, the stability of anaerobic co-digestion system of wheat straw and pig manure was significantly enhanced and the daily biogas yield was more stable. However, after 105days of full reflux of biogas slurry, the contents of TN and TVFAs in biogas slurry accumulated gradually while the daily biogas yield was still stable. In summary, it is feasible to conduct the full reflux of biogas slurry to the anaerobic system in the multi-material biogas plant, but attention should be paid to the accumulation of ammonium nitrogen and TVFAs.
陈广银, 王恩慧, 郑嘉伟, 吴佩, 刘旭, 方彩霞. 沼液全量回流对农业废弃物沼气发酵的影响[J]. 中国环境科学, 2023, 43(S1): 118-124.
CHEN Guang-yin, WANG En-hui, ZHENG Jia-wei, WU Pei, LIU Xu, FANG Cai-xia. Effect of full reflux of biogas slurry on biogas production with agricultural wastes. CHINA ENVIRONMENTAL SCIENCECE, 2023, 43(S1): 118-124.
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