Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
Bioresour Technol. 2019 Jun;281:226-233. doi: 10.1016/j.biortech.2019.02.077. Epub 2019 Feb 19.
This study investigated the impact of mixing on key factors including foaming, substrate stratification, methane production and microbial community in three full scale anaerobic digesters. Digester foaming was observed at one plant that co-digested sewage sludge and food waste, and was operated without mixing. The lack of mixing led to uneven distribution of total chemical oxygen demand (tCOD) and volatile solid (VS) as well as methane production within the digester. 16S rRNA gene-based community analysis clearly differentiated the microbial community from the top and bottom. By contrast, foaming and substrate stratification were not observed at the other two plants with internal circulation mixing. The abundance of methanogens (Methanomicrobia) at the top was about four times higher than at the bottom, correlating to much higher methane production from the top verified by ex-situ biomethane assay, causing foaming. This result is consistent with foaming potential assessment of digestate samples from the digester.
本研究考察了混合对三个全规模厌氧消化器中包括起泡、基质分层、甲烷生成和微生物群落在内的关键因素的影响。在一个同时消化污水污泥和食物废物且未进行混合的工厂中观察到消化器起泡。混合不足导致总化学需氧量（tCOD）和挥发性固体（VS）以及消化器内甲烷生成的不均匀分布。基于 16S rRNA 基因的群落分析清楚地区分了顶部和底部的微生物群落。相比之下，在另外两个具有内部循环混合的工厂中没有观察到起泡和基质分层现象。顶部产甲烷菌（甲烷微菌）的丰度比底部高约四倍，与通过现场生物甲烷测定验证的顶部更高的甲烷生成量相关，导致起泡。这一结果与消化器中消化液样品的起泡潜力评估一致。
