Effect of reflux on population distributions of microorganisms and contaminant removals in start-up of an anaerobic baffled reactor
出水回流对ABR反应器启动过程中污染物去除效果和微生物种群的影响

The effect of reflux on the acidification resistance and the mechanisms of the anaerobic baffled reactor (ABR) has been a research hot topic for the improvement of the operation stability of the high load ABR. With simulated wastewater, room temperature and high load, the effect of reflux on the performance, the volatile fatty acid (VFA) concentration and the microorganism community structure in the start-up period of an ABR was investigated. The results showed that reflux did not affect the COD removal of the ABR significantly, but stablized the pH of the ABR. Reflux decreased the accumulation rate of VFA in ABR by 1/3, so it was beneficial for the reduction of the VFA accumulation. The main microorganisms in the reflux reactor were Brevibacterium, coccus, streptococcus, Bacteroides and so on, and reflux improved the diversity of the microorganisms, thus improving the stability of the microorganism community. The relative abundance of Eubacteria, Archaea, hydrogen-producing acetogenic bacteria and homoacetogenic bacteria in the reflux reactor were higher than that in the non-reflux reactor. Eubacteria, Archaea, hydrogen-producing acetogenic bacteria and homoacetogenic bacteria increased on average by 8.5%, 4.5%, 3.5% and 3%, respectively. In conclusion, reflux could regulate pH, VFA concentration and microorganism community structure, thus improving the anti-acidification ability of the ABR reactor.