曝气条件对铁基复合填料生物滤器脱氮性能及菌群变化的影响

Effects of aeration conditions on nitrogen removal performance and microbial community changes in biological aerated filter with iron-based composite packing

填料和微生物是影响曝气生物滤器(biological aerated filter,BAF)污水处理性能的重要因素,为探究不同曝气条件下曝气生物滤器处理海水养殖废水脱氮性能及填料上微生物群落特征,试验设置3种不同曝气条件的BAF处理组(24 h连续曝气、12 h间歇曝气和0 h曝气),并将聚碳酸亚丙脂(PPC)凝胶亲水填料和海绵铁以3∶1(质量比)混合形成复合固定化生物填料引入BAF系统。结果表明:铁基复合填料12 h间歇曝气处理的氨氮(NH^(+)_(4)-N)去除率高且NO^(-)_(2)-N积累低;12 h间歇曝气处理中海绵铁填料的微生物群落多样性指数(Shannon、Chao1和ACE)高于其他处理组,这说明该处理的微生物群落多样性和丰度最高;12 h间歇曝气处理中海绵铁填料中的不动杆菌属Acinetobacter、代尔夫特菌属Delftia及在PPC填料处理中的发光杆菌属Photobacterium等具备反硝化能力的菌属相对丰度高于其他处理组。研究表明,铁基复合填料BAF在12 h间歇曝气条件下富集了更多的反硝化细菌,使曝气生物滤器具有良好的脱氮性能,同时将节省更多能耗。

In order to investigate the nitrogen removal performance of biological aerated filter(BAF),mariculture wastewater and characteristics of microbial communities on packings were investigated under different aeration conditions.The BAF was treated by three methods with different aeration conditions(24 h continuous aeration.12 h intermittent aeration,and 0 h aeration)and filled with composite immobilized bio-packings prepared by mixing polypropylene carbonate(PPC)gel hydrophilic packing and sponge iron with mass ratio of 3∶1 at water temperature of(30.0±0.5)℃,hydraulic load rate(HLR)of 1.2 m^(3)/(m^(2)·d),carbon to nitrogen ratio of 3∶1 and pH(7.0±0.5).The results showed that there were high removal rate of ammonia nitrogen(NH^(+)_(4)-N)and low accumulation of NO^(-)_(2)-N in the 12 hours aeration group.There was higher microbial community diversity index including Shannon,Chao1 and ACE in sponge iron group than that in other treatments,indicating that the maximal microbial diversity and abundance was observed in the treatment.There was higher relative abundance of the bacterial genus with denitrification ability,including Acinetobacter and Delftia in sponge iron packing and Photobacterium in PPC packing in this treatment than that in other treatments.It was found that the iron-based composite filler BAF enriched more denitrifying bacteria under the condition of 12 h intermittent aeration,which makes the biological aerated filter have good denitrification performance and saves more energy consumption.The findings will provide a theoretical basis for improving the denitrification performance of BAF and analyzing of the microbial community structure of bio-packings in the system.