| Anaerobic Ammonium Oxidation(ANAMMOX)is a promising biological nitrogen removal process with a good application potential.However,the stability and application of the process was usually limited due to the low growth rate of ANAMMOX bacteria and its sensitivity to environment variation.Therefore,in order to understand the characteristics of anaerobic ammonia oxidation process,the stable operating conditions and the inhibition of toxic substances.In this study,the expanded granular sludge bed(EGSB)reactor,the anaerobic granular sludge and aerobic activated sludge was start-up of anammox,and explore the best mode of operation of anaerobic ammonia oxidation stability and subject to the changes of anammox reactor external toxic inhibition.On the basis of the reactor nitrogen removal and sludge extracellular polymers(EPS),in response to changes in microbial community changes and nitrogen metabolism level analysis of multidimensional anammox reactor conditions and inhibition mechanism.The main results are as follows:(1)Two anoxic EGSB reactors were compared for anaerobic ammonium oxidation(ANAMMOX)enrichment with different inoculated sludge,the activated sludge of urban sewage treatment plant(A)and anaerobic granular sludge(B).The activity of anaerobic ammonium oxidation in the reactor was investigated from the shape of sludge,the performance of nitrogen removal,the nitrogen loading rate and the nitrogen removal rate.Illumina Miseq sequencing was conducted to investigate the abundance and diversity of anammox in the bioreactor.Anammox granular sludge was formed in A and B reactor after 119 days of domestication,compared to the B reactor,The A reactor can shorten the Cell lysis phase and Lag phase of anammox start-up process.The Planctomycetes abundance in A reactor were increased faster than B reactor and the Planctomycetes abundance were reached 1.18%?5.98%in A reactor but only reached 0.92%?1.41%in B bioreactor at Cell lysis phase and Lag phase of start-up process.Candidatus Brocadia were the dominated in the genera and the abundance were reached 11.34%and 7.28%in A and B reactor.(2)The influence of hydraulic stress on ANAMMOX reactor performance under different influent nitrogen concentration was carried out,high nitrogen concentration and low hydraulic stress operation of the reactor nitrogen removal efficiency low,the reason is that the anammox activity was inhibited by NO2--N at high nitrogen concentration and low hydraulic,and running mode of low nitrogen concentration high hydraulic can reach good effect.Through the analysis of sludge EPS,the polysaccharide(PS)in the sludge EPS showed an increasing trend during the operation of two running mode.But in the sludge in EPS protein(PN)is decreased in high substrate concentration but in low concentration increased,indicating that a higher protein content in the sludge concentration of EPS(PN)contributes to the stable operation of anaerobic ammonia oxidation reactor,maintain the anammox granular sludge stabilization.The predominant of Phylum were Chloroflexi,Bacteroidetes,Proteobacteria,Firmicutes and Planctomycetes in the anammox sludge.Chloroflexi were the dominant phylum,but on the high substrate concentration of inhibition NO2--N the proportion of Chloroflexi decreased,but increased in the low proportion of matrix high throughput operation,The Chloroflexi as the carrier and the skeleton of anammox sludge.During the high substrate concentration,the anammox bacteria Planctomycetes decreased from 7.31%to 0.92%,on the contrary content of denitrifying bacteria Proteobacteria,Bacteroidetes,Firmicutes increased from 14.55%to 22.45%.However,the Planctomycetes content increased from 7.86%to 10.14%and denitrifying bacteria decreased from 16.37%to 12.23%.The results showed that the low substrate high hydraulic stress operating was more suitable for the enrichment of anammox bacteria.In the genus level,only detected an inhibition of anaerobic ammonia oxidation bacteria Candidatus Brocadia in high substrate concentration under NO2--N abundance decreased from 43.51%to 5.86%,and increased to 56.14%from 40.29%in the low substrate concentration high throughput operation conditions.The genetic variation of functional gene changes of anammox and denitrification function,high concentration of matrix NO2--N inhibited hydrazine oxidoreductase(Hzo)resulting in anaerobic ammonia oxidation is inhibited and the low substrate concentration and high throughput to hydrazine(HzsA)synthase.(3)Through the effect to the successful start-up of anammox reactor adding sulfadimethoxine and sulfamethazine to observe the anammox reactor.sulfadimethoxine on denitrification greater impact,especially in the ability of removing ammonia nitrogen.Based on the analysis of EPS,the concentration of polysaccharide(PS)in the sludge EPS increased with the increasing concentration of sulfonamides antibiotics.EPS protein(PN)content increased with the increase of sulfonamides concentration,protein concentration increased after the decline in antibiotic just added protein concentration increased to form a layer of extracellular protein barrier,sulfa antibiotics will isolate outside cells,but with further increasing concentration,particle sludge disintegration.The protein concentration in EPS sludge reduction.Through the analysis of the different stages of microbial phylum and genus levels,anaerobic ammonia oxidation reactor in F1 and F2 reactor in level on the microbial community framework and supporting role for Chloroflexi,Chlorobi and Ignavibacteriae,but F1 in a single type is mainly Chloroflexi,F2 abundance is abundant,mainly for Chloroflexi,Chlorobi and Ignavibacteriae;denitrifying bacteria were Firmicutes,Bacteroidetes and Proteobacteria,low concentrations of antibiotics have less effect on denitrification,but the high concentration of antibiotic concentration on denitrification inhibition.When the concentration of sulfadimethoxine rose to lmg/L and 3mg/L,the abundance of Planctomycetes anammox in F1 was increased from 4.77%to 6.76%,but when the concentration of sulfadimethoxine further increased to 9mg/L,The abundance was decreased from 6.76%to 1.53%,In the F2 reactor,the concentration of lmg/L and 3mg/L,5mg/L?7mg/L,The Planctomycetes abundance was 21.23%,24.69%,18.28%and 28.61%,but when the concentration was further increased to 9mg/L,the abundance of Planctomycetes decreased to 11.42%.It can be seen from genus that when the concentration of sulfadiazine and sulfamethazine two alloxan were added to F1,F2 to 1mg/L,no abundance of Candidatus Brocadia bacteria affected,but increased when the concentration of sulfadimethoxine was 3mg/L,the abundance Candidatus Brocadia decreased,and concentration of sulfamethazine was 5mg/L,Candidatus Brocadia this decline,showed that high concentrations of sulfadimethoxine and sulfamethazine will cause the inhibition of anaerobic ammonia oxidation,but the inhibition of sulfadimethoxine was more than Sulfamethazine.Sulfadimethoxine of hydrazine synthase(Hzs)NO and NH4+-N for the synthesis of hydrazine inhibits the process between the big Sulfamethazine in high concentration,especially.Sulfadimethoxine of hydrazine oxidoreductase(Hzo)the degree of inhibition is greater than sulfamethazine,with further increase in the concentration of the two reductase(Hzo)for hydrazine oxidation damage and are quite large.When adding sulfadimethoxine,content of denitrifying functional genes NirS and NosZ increased,the sulfamethazine added NirS and NosZ content of denitrifying genes declined,a certain degree of inhibition. |
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