EFFECTS OF CARBON TO NITROGEN RATIO ON DENITRIFICATION PERFORMANCE AND MICROBIAL COMMUNITY IN AN MBBR SYSTEM
Compared the denitrification performance of single-stage moving bed biofilm reactors(MBBR)under two different operation modes,continuous flow,and sequencing batch,by adding synthetic wastewater with different carbon-to-nitrogen(C/N)ratios.Metagenomic sequencing technology was utilized to analyze the microbial community and functional gene abundance of biofilms on carriers in different phases,as well as to analyze the major nitrogen metabolism pathways in the reactor,with the aim of investigating the effects of different C/N ratios and operation modes on the denitrification performance and biofilm community structure of the MBBR system.Results showed that the variation of C/N ratio had little effect on ammonia nitrogen removal of the MBBR process,with ammonia nitrogen removal rates remaining above 95％in all phases.However,there was a significant difference in simultaneous nitrification and denitrification(SND)efficiencies among phases,due to the limitation of denitrification performance.In addition,the total inorganic nitrogen removal rate of the sequencing batch MBBR(SBMBBR)was always higher than that of the continuous flow MBBR(CFMBBR),which may be due to the differences in the total number of functional genes,such as narGHI,napAB,nirK,nirS,norBC,and nosZ,which play a crucial role in denitrification.There were significant differences in the dominant bacterial phyla and species under different operation modes,which was also a major reason for the significant difference in denitrification performance between SBMBBR and CFMBBR.These results can provide useful references for the optimization design and operation of MBBR for the treatment of urban domestic wastewater with lower C/N ratios.
moving bed biofilm reactorcarbon-to-nitrogen ratiomacrogenomic sequencingfunctional genesnitrogen metabolism pathwaymicrobial community structure
NETL
NSTL
万方数据
