Improved stability of up-flow anaerobic sludge blanket reactor treating starch wastewater by pre-acidification: Impact on microbial community and metabolic dynamics

Poor processing stability has been cited as the fatal shortcoming of the up-flow anaerobic sludge blanket (UASB) reactor treating starch wastewater (SW). In this study, the SW treatment performance in a one-stage UASB reactor and a pre-acidification equipped UASB process were evaluated together with the microbial dynamics. The results revealed that the pre-acidification provided improvements in terms of the substrate utilization diversity and the stability of the microbial community structure on the UASB reactor. Anaerolineaceae/Methanosaeta was the core functional microbiota in the pre-acidification equipped UASB reactor, indicated the superior abilities on the acetogenic methanogenesis of granules. The genus of Methanobacterium, a hydrogenotrophic methanogen was dominant in the archaeal community in the one-stage UASB reactor. The granules performed very strong hydrogen affinity in methane production, a small amount of propionate was detected in the effluent. These were abnormal, which suggested the high hydrogen turn-over rate in the one-stage UASB reactor.

Automated summary

The study found that pre-acidification equipped UASB process showed better treatment performance and stability in handling starch wastewater compared to a one-stage UASB reactor, with improvements in substrate utilization diversity and microbial community structure stability. The core functional microbiota of Anaerolineaceae/Methanosaeta in the pre-acidification equipped UASB reactor exhibited superior acetogenic methanogenesis abilities. In contrast, the dominance of Methanobacterium, a hydrogenotrophic methanogen, in the archaeal community of the one-stage UASB reactor indicated a high hydrogen turn-over rate.