纳米铁改性生物炭载体强化厌氧氨氧化菌富集与脱氮效果研究

Research on Nano-Iron Modified Biochar Carrier to Enhance Enrichment and Denitrification Effect of Anaerobic Ammonia Oxidizing Bacteria

为实现厌氧氨氧化菌(AnAOB)在载体生物膜中快速富集,本文采用液相还原方法制备了纳米铁改性生物炭(nZVI@BC)载体,并设置两组相同的厌氧氨氧化(ANAMMOX)富集装置(R_(1)、R_(2)),通过对R_(1)、R_(2)装置添加不同载体(分别为BC和nZVI@BC),考察在富集过程中ANAMMOX装置的脱氮性能、载体表面特征和微生物群落结构差异.结果表明:①BC表面成功负载nZVI,nZVI@BC载体比BC载体具有更高的比表面积,改性后载体的比表面积从47.17 m^(2)/g增至210.82 m^(2)/g,可为微生物提供更多的附着位点.②R_(2)装置NH_(4)^(+)-N和NO_(2)^(−)-N去除率稳定达到90%所需时间均比R_(1)装置短,且稳定运行后,R_(1)、R_(2)装置的TN去除率最高分别为86.99%、89.65%.③nZVI@BC载体表面颜色由黑色变为红褐色,表明红色的ANAMMOX生物膜初步形成,且其表面生物量比BC载体表面生物量高23倍.④第20天,R_(1)、R_(2)装置中AnAOB的相对丰度分别为10.47%和29.15%;R_(1)、R_(2)装置载体表面主要的AnAOB属均为Candidatus Kuenenia,其相对丰度分别为7.49%和23.76%.研究显示,改性的nZVI@BC载体显著促进了ANAMMOX生物膜的快速形成和AnAOB的高效富集,提升了ANAMMOX过程的脱氮性能.

In order to expedite the enrichment of anaerobic ammonia oxidation bacteria(AnAOB)in the carrier biofilms,we synthesized a nano-zero-valent iron modified biochar(nZVI@BC)using liquid-phase reduction techniques.Two parallel anaerobic ammonium oxidation(ANAMMOX)enrichment reactors,designated R_(1)and R_(2),were established,each incorporated with biochar(BC)and nZVI@BC carriers,respectively.This study comprehensively investigated the denitrification performance,carrier surface attributes,and microbial community structure differences during the enrichment phase.The results showed that:(1)nZVI was successfully adsorbed onto the surface of the BC carrier,making nZVI@BC have a high specific surface area and porosity,and modified the specific surface area increased from 47.17 m^(2)/g to 210.82 m^(2)/g,thus providing an augmented platform for microbial adhesion.(2)The R_(2)reactor achieved a stable 90%removal rate for both NH_(4)^(+)-N and NO_(2)^(−)-N more rapidly than R_(1).The total nitrogen removal rates of R_(1)and R_(2)were 86.99%and 89.65%,respectively,during the stable operation.(3)The color of the nZVI@BC carrier surface changed from black to reddish-brown,indicating the initial formation of a red ANAMMOX biofilm.Moreover,the biomass on the nZVI@BC carrier surface was 23 times higher than that on the BC carrier.(4)On day 20,the relative abundance of AnAOB in R_(1)and R_(2)was identified as 10.47%and 29.15%,respectively.The dominant AnAOB genus on the carrier surfaces of R_(1)and R_(2)was Candidatus Kuenenia,with relative abundances of 7.49%and 23.76%,respectively.Overall,the modified nZVI@BC carrier significantly facilitated the rapid ANAMMOX biofilm formation and efficient AnAOB enrichment,enhanced denitrification performance during the ANAMMOX process,and resulted in the selection of advantageous AnAOB strains.