基于电极氨氧化的全程自养脱氮工艺的运行性能

Operational performance of a completely autotrophic nitrogen removal process based on electrode-dependent ammonium oxidation

电极氨氧化作用为NO_(2)^(-)-N稳定获取提供了新思路,如将其与厌氧氨氧化(ANAMMOX)耦合,可弥补基于亚硝化的全程自养脱氮工艺在处理城镇生活污水时不够稳定的缺陷.将ANAMMOX污泥接种至电极氨氧化型序批式生物膜反应器(SBBR)中,考察不同外加阳极电势下系统的氮素转化性能,并探究外加阳极电势对SBBR中基于电极氨氧化的全程自养脱氮作用的影响.结果表明,将外加阳极电势由0.00增至0.60 V,SBBR中电极氨氧化作用的强度、厌氧氨氧化菌(AnAOB)的活性及相对丰度均得以提高,基于电极氨氧化的全程自养脱氮作用成为系统脱氮主要途径;而当外加阳极电势增至0.80 V后,工作电极表面的析氧反应导致SBBR中亚硝酸盐氧化菌过量增殖,电极氨氧化作用也因电势升高受到抑制,导致系统的脱氮效果变差.当外加阳极电势为0.60 V时,SBBR中基于电极氨氧化的全程自养脱氮作用得到较大程度的优化,系统TN去除率达88.36%(±1.50%),电活性生物膜中的优势菌属包括Nitrosomonas(17.67%)、Candidatus Brocadia(16.28%)、Geobacter(7.59%)和Empodebacter(8.84%).本研究表明适宜阳极电势的施加与ANAMMOX污泥的接种有助于生物电化学系统中基于电极氨氧化的全程自养脱氮反应体系的构建,且外加阳极电势会影响系统的脱氮性能及其菌群结构.(图10表1参43)

Electrode-dependent ammonium oxidation is a new approach for the stable acquisition of NO_(2)^(-)-N.Bottlenecks in completely autotrophic nitrogen removal during the nitrite treatment process of municipal sewage will be solved if the technique is coupled with anaerobic ammonia oxidation(ANAMMOX).Therefore,it is necessary to study the operational performance of a completely autotrophic nitrogen removal process based on electrode-dependent ammonium oxidation.In this study,ANAMMOX sludge was inoculated into a sequencing batch biofilm reactor(SBBR)by using an electrode-dependent ammonium oxidation process.Subsequently,the nitrogen transformation performance of the system at different anode potentials was investigated,and the effects of applied anode potential on the completely autotrophic nitrogen removal process based on electrode-dependent ammonium oxidation in the SBBR were explored.The results showed that,as the applied anode potential increased from 0.00 to 0.60 V,the strength of the electrode-dependent ammonium oxidation process improved in the SBBR.The activity and relative abundance of anaerobic ammonia-oxidizing bacteria(AnAOB)in the system significantly increased,resulting in a completely autotrophic nitrogen removal process based on electrode-dependent ammonium oxidation as the primary total nitrogen(TN)removal route in the SBBR.However,as the applied anode potential was increased to 0.80 V,nitrite-oxidizing bacteria proliferated excessively in the SBBR because of the oxygen evolution reaction at the working electrode.Furthermore,the electrode-dependent ammonium oxidation process was remarkably inhibited at an applied anode potential of 0.80 V,inhibiting nitrogen removal of the system.Operating the bioelectrochemically assisted SBBR with an applied anode potential of 0.60 V effectively enhanced the completely autotrophic nitrogen removal process based on electrode-dependent ammonium oxidation in the system,achieving an ideal TN removal rate[=88.36%(±1.50%)].Correspondingly,Nitrosomonas(relative abundance of 17.67%),Candidatus Brocadia(relative abundance of 16.28%),Geobacter(relative abundance of 7.59%),and Empodebacter(relative abundance of 8.84%)were the four dominant bacterial genera in the electroactive ammonia oxidation biofilm that played key roles in nitrogen removal.In summary,the establishment of a completely autotrophic nitrogen removal process based on electrode-dependent ammonium oxidation in a bioelectrochemical system may benefit from the application of an appropriate anode potential and inoculation of ANAMMOX sludge.Moreover,nitrogen removal from the system and the associated microbial community composition were significantly influenced by the applied anode potential.