梯度负荷下果蔬垃圾厌氧消化性能及微生物群落结构的研究

为优化果蔬垃圾厌氧消化工艺,提高厌氧消化性能,本文通过逐级提高CSTR反应器进料负荷,研究不同负荷下的厌氧消化性能及相应的微生物群落结构变化规律.结果表明,随着进料负荷的增高,容积产气率、甲烷产气量、氨氮、碱度、TCOD、SCOD均逐渐增高,在最高负荷(负荷以VS计)2.50g·L-·1d-1时分别达到最大值:1.22L·L-1d-1,5.10L·d-1,1563.86mg·L-1,7572.23mg·L-1,13283.26mg·L-1,2075.03mg·L-1,甲烷含量及VFA分别稳定在52.46%～54.59%和(879.30±18.69)mg·L-1;同时利用PCR-DGGE技术系统分析了厌氧消化中细菌与古细菌的群落结构,测序结果表明,整个过程中拟杆菌(Bacteroidetes)、甲烷鬃菌(Methanosaeta)及甲烷螺菌(Methanospirillum)为优势微生物,随着负荷的提高,甲烷鬃毛菌(Methanosaeta)活性逐渐降低;聚类分析及主成分分析表明,低负荷条件下(1.50g·L-·1d-1、1.75g·L-·1d-1),微生物种类(细菌、古细菌)差别不明显,且基本处于同一阶段.

Investigation on anaerobic digestion performance and microbial structure of vegetable wastes under gradient organic loadings

Performance and microbial community changes were investigated during the anaerobic digestion of vegetable waste in order to provide microbial information for optimizing anaerobic digestion process and improve digestion performance. Completely stirred reactors (CSTR) were used and the organic loading rates (OLR) were increased gradually. The results showed that biogas yield, ammonia nitrogen, alkalinity, TCOD, and SCOD gradually increased as more OLR was applied. They reached maximum values of 1.22L·L^-1d^-1,1563.86 mg·L^-1,7572.23 mg·L^-1,13283.26 mg·L^-1,and 2075.03 mg·L^-1, respectively, at the highest OLR of 2.50 g·L^-1·d^-1. Methane and VFA contents were stable and maintained at 52.46%~54.59% and 879.30 mg·L^-1. PCR-DGGE technology was applied to systematically analyze bacteria and archaea communities and their changes during the process. It was found that Bacteroidetes, Methanosaeta, and Methanospirillum were the dominant microbes in the whole process. However, Methanosaeta activity gradually reduced with ORL increase. Clustering analysis and principal component analysis (PCA) showed that microbial species (bacteria and archaea) were not significantly different at lower OLD (1.50 and 1.75 g·L^-1·d^-1).