不同工艺对污水处理效能及细菌代谢功能的影响

Effects of Different Processes on Wastewater Treatment Efficiency and Bacterial Metabolic Function

污水处理厂工艺单元的选择对污水处理的最终效果起着重要作用。主要考察了污水处理厂不同处理工艺对典型污染物(特别是总氮)去除效果的影响,并从细菌种群结构与代谢功能的差别等角度解析了其内在作用机制。结果表明,相比旋流沉砂池与传统A^(2)O工艺组合,曝气沉砂池与改良型A^(2)O工艺组合更有助于对污水中典型污染物(特别是总氮)的去除。相比旋流沉砂池,曝气沉砂池除砂效果更优,降低了污泥中的无机组分而提升了其生物量;而改良型A^(2)O中的预缺氧池有助于功能细菌的富集和代谢活性的增强,Saprospiraceae、Dechloromonas、Haliangium、Thauera、Nitrosomonas和Saccharimonadales等脱氮细菌的丰度及相关功能基因(hao、nor、nap等)显著增加和上调,因此,其生化系统内的硝化和反硝化速率大幅提高,进而提升了污水厂对总氮等污染物的去除效能。该研究可为深入了解污水厂不同工艺单元对污染物去除效能的内在作用机制以及污水处理厂升级改造工艺选择提供科学依据和理论指导。

The process selection of wastewater treatment plant is critical to the final treatment performance.The effects of different treatment processes on removal of typical pollutants(especially total nitrogen)in wastewater treatment plants were mainly investigated,and the underlying mechanisms were analyzed from perspectives of bacterial community and metabolic function.Compared with a combined process of vortex grit chamber and traditional A^(2)O,the combined process of aerated grit chamber and modified A^(2)O was more conducive to the removal of typical pollutants(especially total nitrogen)from wastewater.Compared with vortex grit chamber,the aerated grit chamber had better sand removal performance,which reduced inorganic components in sludge and increased its biomass.The preanoxic tank in the modified A^(2)O process was beneficial to the enrichment of functional bacteria and the enhancement of metabolic activity.The abundances of typical nitrifying and denitrifying bacteria(e.g.Saprospiraceae,Dechloromonas,Haliangium,Thauera,Nitrosomonas and Saccharimonadales)and numbers of the related functional genes(hao,nor,nap,etc.)were all significantly increased.Therefore,nitrification and denitrification rates in the corresponding biological units were greatly increased,which improved the removal efficiencies of total nitrogen and other pollutants in the wastewater treatment plant.The results provided a scientific basis and theoretical guidance for further understanding the internal mechanism of pollutants removal by different units and selecting the upgrading and reconstruction process in wastewater treatment plants.