处理氨气生物滴滤塔中氮转化途径及生物相分析

Analysis of Nitrogen Transformation Pathway and Biological Phase in Bio-trickling Filter for Removing Ammonia

为了探究除氨生物滴滤塔中氮转化途径及其生物相特征,以氨气(NH3)作为研究对象,在填料塔空塔停留时间为5.7 s,循环液喷淋强度为637 L/(h·m^(2))条件下,进行了平均进气浓度分别为5.21、11.06和17.32 mg/m^(3)(以N为计)的3组试验,NH3平均去除率分别为93.86%、95.12%、96.13%,且出气浓度均低于1 mg/m^(3)(以N为计)。在3组试验过程中,对进气、出气以及循环液中各种化学形态N元素分别进行了检测,通过N质量平衡分析了生物滴滤塔中氮转化途径,结果表明进气中的NH3-N经液相吸收后,很大一部分被微生物利用后直接氧化成NO3--N、NO2--N,少部分N元素被反硝化脱除,还有一部分N元素被转化为Norg。应用Illumina平台高通量测序技术对生物滴滤塔内生物膜中的生物种属进行了分析,结果显示优势菌属为芽孢杆菌属Bacillus、产黄杆菌属Rhodanobacter、慢生根瘤菌属Bradyrhizobium、肠球菌属Enterococcus、类芽孢杆菌属Paenibacillus等,生物滴滤塔内微生物群落主要利用硝化菌群将NH4+-N氧化成硝氮和亚硝氮,并利用反硝化菌群将硝氮和亚硝氮反硝化成N2。

With ammonia(NH3)as the research objective,nitrogen transformation pathway and biological characteristics of bio-trickling filter for ammonia removal were studied.For this purpose,a bench-scaled experimental bio-trickling filter was erected and three groups of the experiments were conducted.Average concentrations of inlet wastewater for each group experiment were set at 5.21 mg/m3,11.06 mg/m3 and 17.32 mg/m3,respectively,and the experimental conditions were the residence time in bio-trickling filter with an empty bed of 5.7 s and the circulating liquid spraying load being 637 L/(h·m^(2)).In this way,the experiment showed that the average removal rates for each of the three groups were 93.86%,95.12%,96.13%,respectively,and the outlet NH3 concentrations were all lower than 1 mg/m3.In addition,various chemical forms of N element in the inlet gas and outlet gas and circulating liquid were detected during the three-group experiments,the nitrogen transformation pathway in the bio-trickling filter were analyzed by the mass balance of nitrogen.The results indicated that NH3-N in the inlet gas was absorbed as NH4+-N in the liquid phase,and a large part of the N element was directly oxidized to NO3--N and NO2--N by micro-organisms,while a small part of N element was removed through the denitrification process,and a part of the N element was converted into Norg.The biological species in the bio-trickling filter were analyzed with Illumina-Miseq,showing that the dominant bacteria were Bacillus,Rhodanobacter,Bradyrhizobium,Enterococcus,Paenibacillus,et al.The microbial community in the bio-trickling filter mainly was composed of nitrifying bacteria which oxidized NH4+-N to nitrate nitrogen and nitrite nitrogen,and composed of denitrifying flora which reduced nitrate nitrogen and nitrite nitrogen to N2.