部分反硝化耦合厌氧氨氧化IFAS系统脱氮性能

采用部分反硝化活性污泥耦合厌氧氨氧化生物膜处理低碳氮比废水(C/TN=1.63),考察生物膜-活性污泥复合系统(IFAS)进行部分反硝化耦合厌氧氨氧化(PD/A)处理低碳氮比废水的可行性及其耦合后两相中功能菌活性与菌群分布变化规律.结果显示,系统耦合运行期间,出水TN为(5.07±0.2)mg/L,去除率为(90.7±0.1)%,厌氧氨氧化途径对TN去除的贡献率高达(86.61±3.4)%;固着相对厌氧氨氧化活性的贡献率为100%,悬浮相上,μ(NO₃^--N)占比为99.32%,μ(NO₂^--N)占比为99.22%;与耦合前相比,悬浮相中硝酸盐还原酶(Nar)活性由(0.43±0.05)μmol/(mg protein·min)增加至(0.49±0.09)μmol/(mg protein·min),亚硝酸盐转化率明显升高(70±2.2)%~(90.01±2.3)%];Illumina MiSeq结果显示,固着相上的优势菌属为Candidatus_Brocadia,且耦合前后丰度无明显变化(33.61%~33.43%),悬浮相上反硝化菌属Prosthecobacter,Ferruginibacter,OLB8丰度增加.以上结果表明,在IFAS系统中可以实现稳定的PD/A协同脱氮,耦合后部分反硝化由悬浮相主导,厌氧氨氧化由固着相主导,厌氧氨氧化菌(AnAOB)与反硝化菌对NO₂^­--N的竞争强化了悬浮相部分反硝化能力.

Performance and microbial community of the partial denitrification coupled with anaerobic ammonia oxidation in an IFAS system

In this study, an integrated fixed-film activated sludge (IFAS) system was established to explore the feasibility of treating low carbon/nitrogen (C/TN=1.63) wastewater by coupling partial denitrification (PD) suspended sludge and anaerobic ammonia oxidation (Anammox) biofilm. During the experiment, As a result, the TN removal efficiency could be up to (90.7±0.1)% with the effluent TN of (5.07±0.2) mg/L, and the Anammox pathway contributed to TN removal reached (86.61±3.4)%. And the contribution of biofilm to anammox activity was 100%, μ(NO₃^--N) accounted for 99.32%, μ(NO₂^--N) accounted for 99.22% in the suspended sludge; indicating that partial denitrification process was dominated in the suspended sludge and Anammox process in the biofilm. Compared with that before coupling, the nitrate reductase (Nar) in the suspended sludge increased from (0.43±0.05) to (0.49±0.09) μmol/(mg protein·min). The nitrite transformation ratio significantly increased from (70±2.2)% to (90.01±2.3)%. In other words, the competition of nitrite between denitrifying bacteria and anaerobic ammonia oxidation bacteria (AnAOB) partially strengthened the partial denitrification process in the suspended sludge. Illumina MiSeq sequencing results show that the abundance of Candidatus_Brocadia, the dominant bacteria in the biofilm (33.61~33.43)%, had no obvious change before and after coupling. In the phase of suspended sludge, the abundance of Prosthecobacter, Ferruginibacter, and OLB8 tended to increase. Evidently, the PD/A technology in the IFAS system will provide technical guidance for its practical application.