| Sulfamethoxazole?SMX?is one of the common antibiotics.It is frequently detected in the water environment.Long-term residues are extremely harmful to the stability of the water ecosystem and human health.Traditional wastewater treatment technology is difficult to achieve effective removal of antibiotics such as SMX.Aerobic granular sludge has the advantages of high biomass,strong load resistance,and easy integration with existing processes,making it one of the most promising wastewater treatment technologies.Aerobic granular sludge technology has great advantages in treating refractory sewage and high-load sewage.In this paper,the effect of SMX on the formation of aerobic granular sludge was studied,and the key factors affecting the efficiency of aerobic granular sludge in the treatment of SMX-containing wastewater were determined,which is beneficial to the application of aerobic granular sludge technology in the treatment of antibiotic-containing wastewater.In this study,SMX-containing wastewater was used as the research object.By operating two sets of SBR reactors with the same specifications,5?g/L of SMX was added to R1 to determine the properties of SMX on the sludge during granulation,the removal efficiency of conventional pollutants,Effects of Extracellular Polymer?EPS?Concentration and Microbial Community Structure.After the granules were formed,the factors affecting the aerobic granular sludge removal efficiency and the corresponding microbial communities in the aerobic granular sludge system were investigated by changing the SMX concentration,organic load,and dissolved oxygen concentration in the incoming water.Dynamic changes.The results show that the addition of SMX in the feedwater will not inhibit the formation of particles,but will affect the particle size and LB-EPS concentration.The average volume particle diameter of the particles in R1 at 45 days is 215.62?m smaller than R2?238.88?m?;the LB-EPS concentration of the particles formed in R2 is 3-7mg/g SS higher than R1.During the granulation process,the average removal rate of COD and ammonia nitrogen was maintained above 91%.No nitrite nitrogen was accumulated in the reactor,and the nitrate nitrogen concentration gradually decreased.Mature granular sludge can remove most of SMX while ensuring regular pollutant removal.The experimental results of the influencing factors study show that the concentration of SMX in the feed water increased from 5?g/L to 4000?g/L,the removal rate increased from74.46%to 92.39%,and the removal load increased from 3.34?gSMX·gSS-1·d-1 to 2.67×103?gSMX·gSS-1·d-1.When the concentration of SMX is 3000?g/L,the removal of conventional pollutants is significantly affected.When the concentration of SMX rises to4000?g/L,the removal effect becomes significantly worse.The influent COD concentration was increased from 200mg/L to 800mg/L,the removal load was gradually reduced,the amount of nitrous nitrogen accumulation increased,and no nitrate nitrogen was present.The DO concentration was reduced from 8mg/L to 4mg/L.When the DO was 4mg/L,the sludge performance deteriorated,and the ability to remove pollutants such as SMX decreased.The high-throughput sequencing of the microbial community structure in the study of aerobic granular sludge formation and the factors affecting the degradation of SMX by aerobic granular sludge showed that the dominant bacteria in the sludge are:Proteobacteria,Bacteroidetes,Actinobacteria.The mycobacteria that may have a degrading effect on SMX during granulation of sludge are norankpSaccharibacteria,Thauera.In the single factor experiment,the dominant bacteria in the sludge after increasing the concentration of SMX were:Flavvobacterium,Paracoccus,Thauera,Bdellovibrio.After the COD concentration was increased,the microbial diversity in the sludge increased significantly.Among them,the more abundant bacterium was Ferribacterium.After the DO concentration decreased,Thiothrix became the dominant bacteria in the sludge,which may be the main reason for the broken particles. |
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