Effect Of Combined Pollution Of Ibuprofen And Copper Ions On Activated Sludge System

With the scarcity of water resources and the increasingly serious water pollution problems in China,sewage treatment has always been a hot issue of concern.However,many non-degradable pollutants such as medicines and personal care products(PPCPs)and heavy metals can inhibit the metabolism and activity of microorganisms,which has a great impact on the biological treatment,especially the stable operation of activated sludge processes.In this study,the SBR process is taken as the core,and the sludge system is deeply explored for the composite pollutants of ibuprofen and Cu(?).In this study,two SBRs were constructed:No.1 and No.2 were experimental groups.After a 120-day acclimation period,the reactor was successfully started,and the stable performance of nitrogen and phosphorus removal was maintained.The average removal rates of COD,TN and TP were 93.0±1.2%,90.0±0.1%and 81.0±0.5%,respectively.Reactor 1 investigated the long-term effects of the ibuprofen and Cu(?)concentrations that were simultaneously increased on the activated sludge system.The research shows that with the increase of IBU/Cu(?)concentration,the performance of activated sludge system is obviously inhibited.During the period of 1000 ug/L IBU and 10 mg/L Cu(?),the average removal rates of COD,TN and TP of the system decreased to 66.0±0.6%,24±3.7%and 40±2.4%,respectively,and the sludge settling performance The sudden drop,the inhibition rate of SOUR reached 77.98%,and the denitrification capacity was greatly deteriorated.In terms of microbial community structure,the uniformity of the system's microbial community decreases,but the number of microbes that can adapt to the environment is increasing,thereby increasing the number of OTUs and the richness of species in the system.Proteobacteria,Alphaproteobacteria,and Defluviicoccus have become the dominant phylum,dominant class,and dominant genus of the system,respectively,indicating their tolerance to complex pollutants.Reactor 2 investigated the effect of increasing concentrations of Cu(?)on the activated sludge system under long-term ibuprofen.The results show that in the presence of ibuprofen,the system performance remains stable.When the concentration of Cu(?)was increased to 5 mg/L,the system performance was still stable,but the fluctuation of the effluent quality increased.As Cu(?)rose to 10 mg/L,the average removal rates of COD and TN dropped to 61.4±2.3%and 32.2±1.5%,respectively.The SVI of sludge decreased by 40.35%,the SOUR value reached a minimum of 4.4 mg O2/(g MLSS h),SAOR,SNRR and SNOR all decreased by more than 60%;combined with the analysis of microbial community structure,it can be seen that the increase of copper ion concentration will reduce the community Diversity causes differences between groups.The microbial community structure of the system is affected by pollutants,and the community structure of the control period cannot be restored.Proteobacteria is a dominant phylum,impacted by changes in Cu(?)concentration,and the abundance of different bacteria and genus in each stage and the response to the external environment are significantly different.Based on the reactor 1,the effects of ibuprofen and Cu(?)on the microbial molecular ecological network in the activated sludge system were further studied.The results show that different concentrations of ibuprofen/Cu(?)have a significant effect on the overall topological characteristics of the molecular ecological network.The low concentration of ibuprofen/Cu(?)reduces the size and complexity of the network.The high concentration of ibuprofen/Cu(?)strengthens the interaction between microorganisms,the complexity of the network,the degree of node aggregation and transmission Increased efficiency.The proportion of the two internally related species(nodes)of Proteobacteria and Bacteroidetes in the molecular ecological network,and the interactions between species are significantly different.The key species in the molecular ecological network are dynamic,but there are certain commonalities.Most nodes in the center node of the module belong to Proteobacteria(31.25%),Bacteroidetes(25%),Chloroflexi(18.75%),and most of the key species in the connected nodes are from Candidatus Competibacter(40%).