酸化处理对牛粪厌氧发酵有机酸和细菌多样性的影响

Effect of Acidification Pretreatment on Organic Acid Contents and Bacterial Communities in Dairy Manure and Its Anaerobic Digestion Performance

预处理可以改变牛粪的性状,提高厌氧发酵性能。文章采用酸化处理,考察了其对物料变化、细菌多样性和厌氧消化性能的影响。结果表明经酸化处理后,牛粪pH值降低,VFA和SCOD均得到提高。牛粪VFA由乙酸、丙酸和丁酸组成,其中乙酸占酸化前后VFA的比例最大,酸化处理使其比例由61%增加到77%。酸化处理后的牛粪进行厌氧发酵,其甲烷产量,甲烷含量,VS去除率和COD去除率均有显著提高。酸化处理前料液中主要有10种细菌类群,优势菌群为Ruminococcaceae和Lachnospiraceae;酸化处理后主要存在6种细菌类群,Porphyromonadaceae为优势菌群。

Pretreatment can change the property of dairy manure, improve the performance of anaerobic digestion. The acidification pretreatment was used for dairy manure in this study and the effect of this pretreatment on the material property, the diversity of bacterial community and the performance of anaerobic digestion were examined. The result showed that, after the pretreatment, pH of dairy manure was decreased, while both VFAs and SCOD content were increased. The VFAs were composed of acetic acid, propionic acid and butyric acid. The acetic acid content was the most both before and after pretreatment, and its proportion in the VFA increased from 61% to 77% after pretreatment. The performance of anaerobic digestion showed that methane production; methane content, volatile solids （VS） removal rate, and COD removal rate were significantly increased after acidification pretreatment comparing with that without acidification. 16S rDNA clone library showed that 10 different bacterial clusters were found in the manure before acidification treatment, the dominant bacteria were Ruminococcaceae and Lachnospiraceae. And 6 bacterial clusters appeared in the clone library after acidification treatment in which the Porphyromonadaceae became the predominant bacteria.