Analysis Of Microecology Characteristics Of Industrial Wastewater Treated By AO Process

As the core part of microecology in the biochemical treatment system of industrial wastewater,the stability of microbial activity and microecological are the important measures to improve the water treatment effect.The microecological environment is complex and changeable in the process of starch industry wastewater treatment,the microbial community structure,the extracellular polymeric substances(EPS)and the soluble metabolites products(SMP)interact,and have great influence on the effluent quality.However,there are relatively few studies on the relationship between microbial community structure,EPS,SMP and water quality in biochemical treatment of industrial wastewater.Therefore,this paper takes the starch industry sewage treatment plant in Hebei province as the research object,and the change of the microbial community structure was analyzed during the unstable period,and the EPS,SMP,the dynamic changes of community structure and its metabolic processes were discussed during the stable operation stage of the AO process by using high-throughput sequencing and excitation-emission matrix(EEM)fluorescence spectroscopy.This paper provides theoretical basis and technical support for further revealing the microecological characteristics of AO wastewater treatment process and optimizing the process conditions of AO.The main contents and achievements of this paper are as follows:1)Monitoring the water quality of the industrial wastewater treatment system throughout the year,microbial community structure changes and its relationship with the effluent quality were analyzed,the results showed that the removal efficiency of COD and ammonia nitrogen reached 87.4%and 98%respectively in the AO process,and the treatment effect was good.The relative abundance of Proteobacteria and Bacteroidetes increased to 49.4%and 26.9%with the increase of pollutant removal efficiency.According to the results of canonical correspondence analysis(CCA),it was found that the main reason for the change of community structure during the industrial wastewater treatment was nitrate concentration and sludge concentration,and both were positive correlation.Experiments showed that the microbial community structure and treatment effect can be changed by regulating the sludge concentration.2)The microecological characteristics was researched by high-throughput sequencing technology and excitation-emission matrix(EEM)fluorescence spectroscopy.The correlation between microbial community,EPS and SMP was also investigated.The results showed that the main components of EPS were fulic acid,tyrosine and tryptophan.the fluorescence intensity of fulic acid was 53.272×10~6au·nm~2,The SMP in the hypoxia segment was mainly the tryptophan and tryptophan protein,and the SMP in the aerobic segment was mainly humus.The total content of the organic matter in the hypoxic segment was 73.432×10~6au nm~2,and the humic content increased along the way.The microbial community structure of each stage showed a significant trend with the change of water quality.The changes of microbial growth in different hypoxia and aerobic segments were different,and the changes of S3,S4 and S5 were obvious while in S6 and S5 is not obvious.3)Through the establishment of laboratory AO simulation device,combined with the actual operation of the sewage plant to interpret the effect of both COD and ammonia on the treatment of microbial community structure differences.The influent COD and ammonia nitrogen were 500 mg/L and 450 mg/L,respectively.In reactor system,the effluent concentrations were 78 mg/L and 107 mg/L,and the removal rates were 84.4%and 76.2%,respectively.Meanwhile,Proteobacteria,Bacteroidetes,Chloroflexi,Firmicutes,Actinobacteria and Candidate division TM7 were the major phylum in each sample.The most obvious difference between the sewage plant system and small test device were Firmicutes,Saprospiraceae and Betaproteobacteria.From all the results,the pollutants not only could be removed obviously,but also the mechanism was explored by microbial community analysis in the reactor,which supplied a support for the adjustment of AO in industrial wastewater treatment.In this study,the research of laboratory device and actual wastewater treatment plant was carried out,combined with high-throughput sequencing and three-dimensional fluorescence spectroscopy,the interaction between microbial community structure,EPS and SMP in AO process of starch wastewater was revealed,which provided a new technical way for the optimization of biological treatment parameters of industrial wastewater.