Study On Bio-characteristics Of Urban Domestic Sewage Simulated By Multi-point Influent OAO Process

With the rapidly development of China's economy since the reform and opening up,the environmental issues have become more and more serious.Thus,a good water environment is necessary.High-efficiency nitrogen and phosphorus removal is an important part of urban sewage treatment.A high efficiency organic carbon,nitrogen and phosphorus simultaneous removal technology has a very broad application prospect.In this experiment,the multi-point influent OAO process and the AO process were placed in the same environment.Under the same flow of influent water and seed sludge,the removal of pollutants,the distribution of microbial communities,and the differences in dominant bacteria of the two processes in the sludge acclimation period were studied.The main conclusions were as follows:(1)The activated sludge acclimation in the multi-point influent OAO process was more difficult than AO process during sludge acclimation.In addition,the removal rates of COD,ammonia nitrogen,and phosphorus in the multi-point influent OAO process were lower than AO process.After the acclimation of sludge,the removal rates of COD and ammonia nitrogen in the multi-point influent OAO process were similar to those of AO process.The removal rates of COD and ammonia nitrogen in the two processes were both kept stable,and the average removal rates of COD and ammonia nitrogen in the two processes were differed in 1%.The removal rates of total nitrogen and total phosphorus in the OAO process were about 6% and3% higher than that of the AO process,respectively.(2)The 16 SrDNA high-throughput sequencing technology was used to analyze the microbial communities in the multi-point influent OAO process and AO process.According to the results of Venn diagram,PCA analysis and PLA-S analysis,the richness of microbial species in the multi-point influent OAO process was higher than that of AO process.(3)The dominant bacteria phylum in the five reaction pools of the two processes were Proteobacteria and Bacteroidetes.And Proteobacteria accounted for absolute superiority.the relative abundance of Proteobacteria ranged from 48.38% to 72.45%.The dominant bacteria classes in the two processes were Gammaproteobacteria,Betaproteobacteria,and Saprospirae.The relative abundance of those in the OAO process and AO process was 19.28%~24.67%,19.24%~26.98%,13.42%~16.67%,and 43.07%~48.38%,20.36%~22.30%,8.83%~10.20%,respectively.The dominant orders in the two processes were Xanthomonadales,Burkholderiales,Saprospirales,Rhodocyclales,and Nitrospirales.The relative abundance of Thiotrichales in AO process was higher than the multi-point influent OAO processes,while the relative abundance of Sphingobacteriales,Rhodocyclales,and Nitrospirales was lower.The dominant bacteria families in OAO process were Comamonadaceae,Xanthomonadaceae,Saprospiraceae,Rhodocyclaceae,and Nitrospiraceae.In AO process,the dominant bacteria families were Comamonadaceae,Xanthomonadaceae,Pseudomonadaceae,Thiotrichaceae,and Rhodocyclaceae.The relative abundance of those bacteria families was lower than that of the OAO process except for Pseudomonadaceae and Thiotrichaceae.The dominant bacteria genus of OAO process were Thermomenas,Dechloromonas,Nitrospira,Flavobacterium and Rhodobacter.But the dominant bacteria genus AO process were Pseudomonas,Thiothrix,Dechloromonas and Nitrospira.The dominant species of OAO process were Thermononas-fusca and Nitrospira-moscoviensis.In AO process,the dominant species were Pseudomonas_veronii,Thiothrix_Eikelboomii,Nitrospira_moscoviensis,and Janthinobacterium_ividum.