Population dynamics during startup of thermophilic anaerobic digesters: The mixing factor

详细信息    查看全文

• 作者：Sophia A. Ghanimeh ; Pascal E. Saikaly ; Dong Li ; Mutasem El-Fadel
• 关键词：Thermophilic anaerobic digestion ; Mixing ; Startup ; Microbial dynamics ; 16S rRNA gene pyrosequencing
• 刊名：Waste Management
• 出版年：2013
• 出版时间：November, 2013
• 年：2013
• 卷：33
• 期：11
• 页码：2211-2218
• 全文大小：533 K

文摘

Two thermophilic digesters were inoculated with manure and started-up under mixed and stagnant conditions. The <em>Archaeaem> in the mixed digester (A) were dominated by hydrogenotrophic <em>Methanobateriaceaeem> (61 % ) with most of the methane being produced via syntrophic pathways. <em>Methanosarcinalesem> (35 % ) were the only acetoclastic methanogens present. Acetate dissipation seems to depend on balanced hydrogenotrophic-to-acetotrophic abundance, which in turn was statistically correlated to free ammonia levels. Relative abundance of bacterial community was associated with the loading rate. However, in the absence of mixing (digester B), the relationship between microbial composition and operating parameters was not discernible. This was attributed to the development of microenvironments where environmental conditions are significantly different from average measured parameters. The impact of microenvironments was accentuated by the use of a non-acclimated seed that lacks adequate propionate degraders. Failure to disperse the accumulated propionate, and other organics, created high concentration niches where competitive and inhibiting conditions developed and favored undesired genera, such as <em>Halobacteriaem> (65 % in B). As a result, digester B experienced higher acid levels and lower allowable loading rate. Mixing was found necessary to dissipate potential inhibitors, and improve stability and loading capacity, particularly when a non-acclimated seed, often lacking balanced thermophilic microflora, is used.