摘要:
从微生物优势菌群构成角度揭示一体式全程自养脱氮反应器(completely autotrophic nitrogen removal overnitrite,CANON)启动、稳态运行及崩溃的微观机理,有助于优化调控微生物种群、增强CANON的脱氮效能.试验采用序批式反应器(sequencing batch reactor,SBR),以间歇曝气方式启动CANON系统(35益依1益),考察了CANON系统从启动、稳定到恶化过程的氮素转化率和微生物活性;同时对污泥样品采用16S r DNA宏基因组高通量测序技术,考察种泥和不同脱氮效能时期的微生物种群结构.试验结果表明:本CANON系统的厌氧氨氧化菌(anaerobic ammonium oxidation bacteria,An AOB)为Candidatus Kuenenia,氨氧化菌(ammonium oxidation bacteria,AOB)和硝化菌(nitrite oxidation bacteria,NOB)分别为亚硝化单胞菌属(Nitrosomonas)和Uncultured Nitrospinaceae;系统启动时,An AOB丰度达到0.44%,AOB和NOB分别占总菌的27.61%和1.33%,脱氮效果最佳时的总氮容积去除率达到218.0 mg/(L·d);由于系统溶解氧质量浓度较低(0.15~0.25 mg/L),好氧段发生厌氧氨氧化反应,好氧段结束时亚硝氮积累量持续下降,导致缺氧段亚硝酸盐基质不足,An AOB受到抑制;长期运行条件下,反应器内生物多样性及An AOB丰度均有所下降.反应末期,Nitrosomonas占总菌群数量的62%,成为优势菌种,而An AOB仅占0.13%,与此时较低的总氮容积去除率(19.3 mg/(L·d))相吻合.
Abstract:
Research achievements regarding bacterial community dynamics of completely autotrophic nitrogen removal over nitrite(CANON) systems are helpful to improve the understanding of biological nitrogen removal processes and to better operation control.In this study,a lab-scale one stage nitritationanaerobic ammonium oxidation(Anammox) sequence batch reactor(SBR) was operated at 35 ℃ ±1 ℃under a regime of intermittent aeration.The full life cycle of a starting-up progress was studied,which covered a start-up phase,a quasi-steady-state phase and a final deterioration phase.High-throughput sequencing technology was employed to identify the microbial communities in different stages.The highest volumetric nitrogen removal rate of 218.0 mg/(L·d) was obtained after two weeks of start-up.16 S rDNA sequencing analysis revealed that the three functional bacteria took different proportions related to the total bacteria,i.e.,0.44% ,27.6% and 1.33% for anaerobic ammonium oxidation bacteria(AnAOB),ammonium oxidation bacteria(AOB) and nitrite oxidation bacteria(NOB) respectively.Anammox process occurred in the aeration phase due to the low dissolved oxygen,resulted in the gradual decline of the accumulated NO2--N at the end of the aeration phase.While at the last phase of the anoxic,AnAOB was suppressed for the depletion of NO2--N.At the end of the operating life cycle,Nitrosomonas established a stable foothold in the community(62% ),while the AnAOB species only occupied 0.13% ,which agreed well with the declined total nitrogen removal rate(19.3 mg/(L·d)).
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