Construction And Application Of Highly Efficient Aerobic Denitrification Core Microflora

Aerobic denitrification bacteria have been paid more attention and studied because they have the ability of aerobic denitrification,can realize simultaneous nitrification and denitrification when applied to the sewage system,and can enhance the biological denitrification ability of the sewage treatment system.Although there are many kinds of aerobic denitrification strains and they exist widely in nature,it is not easy to obtain strains with efficient aerobic denitrification capacity and can continue to play a role in the sewage treatment system.In order to obtain strains with high efficiency aerobic denitrification capability and potential for industrial application,this study started from rapid screening of high efficiency aerobic denitrification strains,explored the factors affecting the aerobic denitrification performance of strains,rationally designed and constructed a multi bacteria system,and then prepared immobilized bacteria,focusing on the effect of immobilized bacteria in actual wastewater treatment and its impact on the composition and succession of microbial communities in the original system.1.Rapid screening of highly efficient aerobic denitrification strains and16S r RNA identification.In order to obtain different types of efficient aerobic denitrification strains,three efficient aerobic denitrification strains W-2,W-3and G-2 were obtained by enrichment,separation and purification from samples from different sources such as activated sludge,sewage and shallow soil.Perform 16S r RNA sequence alignment and phylogenetic analysis of the strain,and preliminarily identify the strain W-2 as Stutzerimonas stutzeri,W-3as Prescottella defluvii,and G-2 as Azospirillum argentense.These three strains of bacteria can all remove three different forms of nitrogen elements:nitrate nitrogen（NO₃^--N）,nitrite nitrogen（NO₂^--N）,and ammonia nitrogen（NH₄⁺-N）.Strain W-2 has a better removal effect on NO₃^--N and NO₂^--N within 120 hours,with removal rates of 98.88%and 99.98%,respectively.Strain W-3 and G-2 have a better removal effect on NO₃^--N and NH₄⁺-N within 120 hours,with removal rates of 96.01%and 85.22%,99.05%and85.41%,respectively.2.Study on the removal of nitrate nitrogen by highly efficient aerobic denitrification bacteria.The effects of different carbon sources,C/N and strain ratio on the aerobic denitrification capacity of the strain were investigated.The results showed that sodium acetate was the optimal carbon source for aerobic denitrification of the three strains,and the removal rates of nitrate nitrogen by strain W-2,W-3 and G-2 were 99.12%,12.29%and 64.70%respectively within 48 h.The optimal C/N for aerobic denitrification of strain W-2 and W-3was 25,and the removal rates of NO₃^--N were 70.88%and 24.01%within 48hours,respectively.The optimal C/N for aerobic denitrification of strain G-2was 20,and the removal rate of NO₃^--N was 91.21%within 48 hours.The combination of three bacteria mixed in equal proportions has the best removal effect on NO₃^--N,with a removal rate of 50.03%.3.Immobilization and application of efficient aerobic denitrification core bacteria.In order to colonize the high efficient aerobic denitrification core bacteria in the wastewater treatment system to play a role,the bacteria were prepared into immobilized bacteria agent and added to the reactor to explore its impact on the reactor treatment performance,microflora composition and succession.The results showed that compared with the control check（R₁）,the bio-based polyurethane sponge composite bacterial agent（R₂）,free composite bacterial agent（R₃）,and activated carbon bacterial agent（R₄）had no significant effect on the MLSS,SV₃₀,SVI₃₀,and SV₅/SV₃₀indicators of activated sludge in the reactor.After adding the composite bacterial agent,the MLSS of R₁,R₂,R₃,and R₄activated sludge was 6882 mg/L,6766 mg/L,6731 mg/L,6965 mg/L,and SVI₃₀was 101.71 m L/g,respectively 104.94m L/g,109.94 m L/g,99.07 m L/g.After the addition of different compound agents,the relative abundance of Proteobacteria in R₂,R₃and R₄microflora,which covers the majority of aerobic denitrification strains,increased from88.30%,85.86%and 87.60%to 97.40%,96.09%and 93.31%,respectively,while the abundance of Proteobacteria in R₁decreased from 92.11%to70.06%.In this paper,we successfully designed and constructed the efficient aerobic denitrification core microflora,fixed it on the bio based polyurethane sponge to prepare a composite bacteria agent,and applied it to the treatment of semi simulated vitamin B₁production wastewater.The results showed that the composite bacteria agent could maintain the stability of the treatment system and enable the composition of the bacteria group to evolve in the direction of enhancing aerobic denitrification.