Responses of MBBR system with magnetic carrier to nano-ZnO partical stress
To investigate the response of the moving bed biofilm reactor(MBBR)with magnetic carriers to different concentrations of nano-ZnO stress,two sets of MBBRs were constructed to conduct nano-ZnO stress experiments.By comparing the performance of COD,NH4+-N removal,biofilm morphology,microbial community and functional genes of ordinary carriers with the magnetic carriers,the influence of magnetic carrier on pollutant removal performance and microorganisms in MBBR under nano-ZnO stress was analyzed.The results showed that low concentration(5,10mg/L)of nano-ZnO had no significant effect on COD and NH4+-N removal.After the stress of 30 and 50mg/L nano-ZnO,the NH4+-N removal of magnetic carrier MBBR decreased by 10.57％and 12.91％,respectively,lower than the 14.48％and 16.94％of ordinary carriers.Compared with NH4+-N,nano-ZnO stress had less effect on COD removal.In addition,more nano-ZnO particles were accumulated and adsorbed on the biofilm of magnetic carrier under high concentration(30,50mg/L)of nano-ZnO stress,thereby altering the community structure of biofilm.Under 10mg/L nano-ZnO stress,the relative abundance of Micropruina in both magnetic and ordinary carrier biofilms increased,promoting the growth of the genus.50mg/L nano-ZnO significantly inhibits the growth of Micropruina,and its relative abundance in ordinary and magnetic carrier biofilms decreased to 0.20％and 1.28％,respectively.The prediction of KEGG metabolic pathway indicated that high concentration of nano-ZnO improved the functions of cell membrane transporters and cell activity,while reduced the functions of carbohydrate metabolism,amino acid metabolism,energy metabolism,cofactor and vitamin metabolism,as well as heterologous degradation and metabolism.under the stress of nano-ZnO,magnetic carriers exhibit better pollutant removal performance than ordinary one,weakening the stress effect of nano-ZnO on microorganisms.
万方数据
维普
