长期低温对絮状-颗粒耦合CANON脱氮及菌群影响

Effect of long-term low temperature on nitrogen removal and microbial community of flocculent-granular coupling CANON

在SBR反应器中探究长期低温对等污泥浓度比例絮状-颗粒(1:1~1:1.5)耦合CANON系统的脱氮效能和微生物群落结构的影响.结果表明,在经历长期低温(10℃)条件下运行并回温(10→30℃)后,等比例污泥CANON系统NH_(4)^(+)-N、TN去除率及TN去除负荷与温度变化呈正相关性,在回温30℃下运行30d后分别达到72.4%、63.0%和0.094kgN/(m^(3)·d).氨氧化菌(AOB)和厌氧氨氧化菌(AAOB)活性与温度表现出正相关性,在回温后分别为0.025和0.049gN/(gVSS·d),分别为降温前(30℃)的83.3%和79.1%,NOB活性一直维持在较低水平(0.001gN/(gVSS·d)).高通量测序结果显示,长期低温对优势菌门无明显影响.回温后,颗粒和絮状污泥中的优势菌门分别为Ignavibacteriae和Proteobacteria;回温后系统颗粒污泥中功能菌Candidatus Brocadia、Candidatus Kuenenia(AAOB)相对丰度分别为6.017%、2.623%,其在絮状污泥中相对丰度分别为3.018%、0.674%,而Nitrosomonas(AOB)主要存在于絮状污泥中,在回温后相对丰度为2.50%;3种功能菌相对丰度均高于降温前水平.等比例絮状-颗粒耦合CANON系统能有效抵御长期低温.

The effects of long-term low temperature on nitrogen removal efficiency and microbial community structure of CANON system with equal sludge concentration ratio of flocculent-granular(1:1~1:1.5)in SBR reactor were studied in this study.The results showed that after long-term operation at low temperature(10℃)followed by recovery from low temperature(10→30℃),the removal efficiencies of NH4_(+)^(-)N、TN and NRR in equal proportion sludge CANON system were positively correlated with temperature,and reached 72.4%,63.0%and 0.094kgN/(m^(3)·d),respectively,after 30days of operation at 30℃.The activities of AOB and AAOB showed positive correlation with temperature,and reached 0.025 and 0.049gN/(gVSS·d)after recovery from low temperature,about 83.3%and 79.1%of those before cooling,respectively.NOB remained at a low level(0.001gN/(gVSS·d)).The results of high-throughput sequencing showed that long-term low-temperature had no effect on the dominant taxa at phylum level.The dominant phyla of granular and flocculent sludge after rewarming were Ignavibacterium and Proteobacteria respectively.After recovery,the relative abundances of functional bacteria Candidatus brocadia and Candidatus kuenenia(AAOB)in granular sludge were 6.017%,2.623%respectively,and their relative abundances in flocculent sludge were 3.018%and 0.674%respectively.While Nitrosomonas(AOB)mainly distributed in flocculent sludge,and its relative abundance after recovery was 2.50%.The relative abundances of three functional bacteria were higher than the level before cooling.The equal proportion flocculent-granular sludge CANON system can effectively resist long-term low temperature.