PVC纤维棉上生物膜的形成及其硝化性能研究

Study on biofilm formation and nitrification performance of PVC fiberfill

研究了一种纺织工业原料PVC纤维棉用作生物膜法载体时促进生物膜形成的影响因子及硝化膜的硝化性能。生物膜形成过程中,生物膜上有机物的存在有利于纤维棉上亚硝化单胞菌的“成熟”,生物膜完成第一步“成熟”所需的时间为13～15d。一定水平的磷酸盐有利于纤维棉上硝化杆菌的“成熟”,保持磷酸盐质量浓度0.3mg·L-1以上,生物膜完成第二步“成熟”只需24～26d,比对照组提早5～6d“成熟”。“成熟”PVC纤维棉上异养细菌在(4.8～7.2)×105CFU·cm-3,亚硝化单胞菌在(2～2.3)×105CFU·cm-3,硝化杆菌在(6.4～8.6)×104CFU·cm-3。“成熟”PVC纤维棉在遇到氨氮负荷冲击时,氨氮降解和亚硝酸氮降解是不同步的,存在时滞,导致临时的高水平亚硝酸盐现象。“成熟”PVC纤维棉25℃的最大氨氮去除速率和最大亚硝酸氮去除速率分别为(269.4±4.82)mg·m-2·h-1、(168.1±13.1)mg·m-2·h-1。

The influence of several factors on biofilm formation on PVC （Polyvinyl chloride） fibrefill and its nitrification performance were studied when it was used as media in the biofilm technique. In the process of forming biofilm, the existence of organics was in favor of establishing Nitrosomonas on the fiberfill. The mature time of Nitrosomonas on fiberfill was 13-15 days. The given level of phosphate was advantageous to develop Nitrobacter on media. When the phosphate levels were maintained above 0.3 mg·L^-1 in the water, the mature time of Nitrobaeter on fiberfill was 24-26 days, which was5-6 days less than the control. The numbers of Heterotrophic bacteria, Nitrosomonas and Nitrobaeter on the mature biofilm reached respectively （4.8-7.2）×10^5 CFU·cm^-3, （2-2.3）×10^5 CFU·cm^-3 and （6.4-8.6）×10^4 CFU·cm^-3. When encountered by ammonia shock, there existed the time lag between TAN （Total ammonia nitrogen） and nitrite removal because of the imbalance between ammonia oxidization and nitrite oxidization by fiberfill biofilm, expressing as the transient accumulation of nitrite. The optimal TAN or nitrite removal rate of mature fiberfill averaged respectively （269.4±4.82） mg·m^-2·h^-1 or （168.1±13.1 ） mg·m^-2·h^-1 at 25 ℃.