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

出水回流对厌氧折流板反应器(ABR)抗酸化性能及机制的影响研究是提升高负荷ABR稳定运行研究的热点.因此,本文采用ABR处理模拟废水,采用常温、高负荷启动方式,研究回流对ABR启动过程中运行效果、挥发性脂肪酸(VFA)及微生物种群分布的影响.结果显示,回流对ABR的COD去除率影响不大,但可使反应器的pH值更稳定;回流反应器中的VFA累积速率降低了1/3,有利于减少VFA的积累;回流反应器中的微生物主要有短杆菌、球菌、链球菌及拟杆菌等,回流提高了反应器中的微生物多样性,从而提高了微生物种群的稳定性.回流反应器中真细菌、古细菌、产氢产乙酸菌和耗氢产乙酸菌的相对丰度均高于不回流反应器,真细菌平均高出8.5%,古细菌平均高出4.5%,产氢产乙酸菌和耗氢产乙酸菌分别高出3.5%和3.0%.通过回流能够调控pH值、VFA浓度、微生物种群结构及分布,进而提升ABR反应器的抗酸化性.

Effect of reflux on population distributions of microorganisms and contaminant removals in start-up of an anaerobic baffled reactor

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.