纳米ZnO胁迫下SBBR污染物去除性能及微生物群落响应

为探究生物膜处理系统对纳米ZnO的耐受性能，构建序批式生物膜反应器（SBBR）开展纳米ZnO对生物膜的胁迫试验.计算纳米ZnO在生物膜中的累积量，研究其对有机物、氮、磷的去除性能影响，判定SBBR对纳米ZnO的耐受阈值.通过测定生物量、微生物活性及群落结构变化，分析微生物群落对纳米ZnO的响应.结果表明：低浓度（1~10mg/L）纳米ZnO对COD、NH₄⁺-N、溶解性磷（SOP）去除无显著影响，但5mg/L纳米ZnO对微生物代谢速率和生物活性产生促进作用.纳米ZnO浓度逐增至50mg/L，对生物量、微生物活性抑制作用增强，COD、NH₄⁺-N、SOP去除率分别下降26.45%、57.83%和43.50%.纳米ZnO的胁迫对SBBR中COD去除性能影响最小，对NH₄⁺-N影响较大.COD所指示SBBR的纳米ZnO耐受阈值为911.49mg，而NH₄⁺-N、SOP所指示的耐受阈值为579.83mg.纳米ZnO的胁迫降低了系统中微生物群落的多样性，改变了群落结构组成，Proteobacteria和Chlorofiexi相对丰度由21.09%和7.03%分别降至8.00%和2.60%，致使NH₄⁺-N去除受到显著抑制；Patescibacteria丰度由9.33%突增至56.64%，为有机物的去除起到至关重要的作用.污染物去除性能及微生物活性表明，SBBR生物膜系统对纳米ZnO的耐受性强于活性污泥法.

Performance of pollutant removal and responses of microbial community to Nano-ZnO stress in SBBR

In order to explore the tolerance of biofilm treatment system to Nano-ZnO, a sequencing batch biofilm reactor (SBBR) was constructed to carry out the Nano-ZnO stress test in SBBR system for determining the accumulation characteristics of Nano-ZnO on biofilm, investigating the removal performance of organic matter, nitrogen and phosphorus, and evaluating the Nano-ZnO tolerance threshold of SBBR. The responses of microbial community to Nano-ZnO were also analyzed by observing the changes of biomass, microbial activity and community structure. The results showed that low concentration (1~10mg/L) Nano-ZnO had no significant effect on the removal of COD, NH₄⁺-N and SOP in SBBR except that 5mg/L Nano-ZnO promoted the microbial metabolic rate and biological activity. While the concentration of Nano-ZnO increased to 50mg/L, the inhibition on biomass and microbial activity increased, and the removal of COD, NH₄⁺-N and SOP decreased by 26.45%, 57.83% and 43.50%, respectively. Nano-ZnO stress had the least effect on COD removal performance, but a great effect on NH₄⁺-N. The Nano-ZnO tolerance threshold of SBBR indicated by COD was 911.49mg, while that of NH₄⁺-N and SOP was 579.83mg. The diversity of microbial community in SBBR was reduced and the composition of community structure were changed under the stress of Nano-ZnO. The relative abundance of Proteobacteria and Chlorofiexi decreased from 21.09% and 7.03% to 8.00% and 2.60%, respectively, resulting in significant inhibition of NH₄⁺-N removal. The abundance of Paesciabacteria suddenly increased from 9.33% to 56.64%, which played an important role in the efficient removal of organic matter. The pollutant removal performance and microbial activity showed that the tolerance of SBBR biofilm system to Nano-ZnO was stronger than that of activated sludge process.