The Structure And Function Of Microbial Communities In The Coking Wastewater AOHO Biological Treatment System

The activated sludge method has good economic and environmental benefits in the treatment of coking wastewater with is highly toxic and refractory pollutants.The structure and function of microorganisms involved in the bioreactors are the hot spot.The new coking wastewater AOHO biological treatment process has a good synergistic effect of carbon-and nitrogen-containing pollutant removal,but the comprehension in the microbial structure,functions and the relationships of environment factors and microorganisms are limited.The deep study of microbial diversity,function and the environmental factors can provide a theoretical basis for the highly coordinated removal of carbon and nitrogen pollutants in coking wastewater.What's more,some microbial and gene resources may be contained in the environment of highly toxic coking wastewater.In this study,the microbial communities in different bioreactors of the coking wastewater AOHO biological treatment system were chose as the research object.In order to reveal the key taxon,illustrate major the functions of the microbial community in different bioreactors,elucidate the main driving factors,the microbial diversity,function and ecological relevance were studied by the Illumina high-throughput sequencing technology and functional predicted PICRUSt software.The main results were as follows:(1)In the bioreactor A,the major phyla were Proteobacteria,Firmicutes,Bacteroidetes and Acidobacteria,and the major genera were Bacillus,Rhodoplanes,Thiobacillus,Nitrospira,T78,Planctomyces,Leucobacter and HA73.These bacteria were capable to degrade hydrocarbons and to remove carbon-containing pollutants,such as phenols.Results of functional prediction indicated that Bacillus could provide CYP450 enzyme to promote the transformation of toxic Ba P compounds.Results of PCA analysis between environmental factors and microbial communities showed that SRT and phenolic pollutants were the main environmental factors that regulated the community.In addition,the co-occurrence network analysis revealed that the key OTU group of bioreactor A was Bradyrhizobiaceae,Ignavibacteriaceae,Planctomyces,Thiobacillus and Nitrospira.(2)Proteobacteria,Acidobacteria,Bacteroidetes,WPS-2 and Chlorobi were the major phyla and Thiobacillus,Rhodoplanes and Bdellovibrio were the major genera in the bioreactor O1.The main functions of microbial community in the bioreactor O1 was to oxidize organic matter and NH₃-N.What's more,the PCA results showed that the environmental factors of MLSS,NO₂^-and NH₃-N principally shaped the microbial communities in bioreactor O1.The co-occurrence network analysis revealed that Weeksellaceae and Planctomyces were the key microbial groups in bioreactor O1.(3)In the bioreactor H,the major phyla were Nitrospirae,Proteobacteria,Planctomycetes,Chlorobi,Bacteroidetes,Chloroflex and Cyanobacteria and the major genera were Nitrospira,Thiobacillus,Rhodoplanes and Planctomyces,which were responsible for the decomposition of macromolecular organic compounds and denitrification.The PICRUSt results showed that the relative abundance of denitrifying gene nos Z was the highest one in the bioreactor H.The PCA analysis displayed that the NH₃-N and NO₂^-were the main driving factors regulating the microbial community in the bioreactor H.Co-occurrence network analysis showed that Nitrosomonadaceae,Hyphomonadaceae and Rhodoplanes were the key taxons of microbial community in the bioreactor H.(4)The major phyla of the bioreactor O2 included Acidobacteria,Proteobacteria,Planctomycetes,Nitrospirae,Bacteroidetes and Cyanobacteria,and the major genera included Nitrospira,Thiobacillus,Sphingobium and Planctomyces,which were capable of nitrification and denitrification and degradation of the refractory pollutants.The PCA results indicated the microbial groups were mainly regulated by COD and p H.Co-occurrence network analysis revealed that the key microorganisms were Rickettsiaceae and Hyphomonadaceae.To sum up,this study revealed the microbial community structure,dominant microbial populations,major functional metabolic pathways and the relationships between the microorganisms and environmental factors in different bioreactors of the coking wastewater AOHO biological treatment system.The driving factors regulating the growth and metabolism of microbial community in activated sludge were clarified by correlation statistical analysis.The research results were expected to provide new theoretical basis for the design and optimization of biological treatment process of coking wastewater.