氨氮浓度对CANON工艺性能及微生物特性的影响

为了考察氨氮浓度对CANON反应器启动过程、运行性能及微生物特性的影响,在2个相同的常温MBR反应器内同时接种取自城市污水厂的普通活性污泥,在限氧条件下启动CANON工艺.其中R1进水氨氮保持80mg/L不变,通过逐渐减小HRT启动,R2则保持HRT不变,通过逐渐增加进水氨氮启动.启动成功后,2个反应器分别在不同氨氮浓度下稳定运行相同时间后,取泥样做扫描电镜观察反应器内微生物形态.同时采用克隆-测序分析技术对2个反应器内全细菌进行16S rRNA分析,鉴定反应器内功能微生物种属.结果表明,R1和R2的启动时间分别为78,50d.TN去除负荷分别达到0.9,0.7kg/(m3·d)以上.反应速率测定结果表明,高氨氮运行的反应器内亚硝化菌和厌氧氨氧化菌具有较高的活性,NOB被抑制或淘洗的较为彻底.SEM及克隆测序结果表明,2个反应器中的功能微生物均为亚硝化单胞菌和待定斯图加特库氏菌,R1中存在少量硝化杆菌,而R2中几乎检测不到硝化菌.因此,高氨氮下运行的反应器具有更高的活性及稳定性.

Effect of ammonia concentration on the performance and microbial characteristics of CANON process

In order to study the influence of ammonia concentration on CANON process, conventional activated sludge was seeded to two identical MBR at ambient temperature, which were named R1 and R2, respectively. Under oxygen-limited condition, R1 was started-up by decreasing HRT, while R2 was started-up by increasing influent ammonia concentration. Then R1 and R2 were fed with ammonia of 80and 200mg/L, respectively. SEM and clone-sequencing were used to analyze the morphology and microbial community of the functional bacteria. The start-up period of R1 and R2 were 78 and 50d, and the NRR were 0.9 and 0.7kg/(m3·d), respectively. The bioactivity of AerAOB and AnAOB in the reactor fed with high ammonia was higher than that of the reactor with low ammonia, while that of NOB showed a contrary result. Results of SEM and clone-sequencing indicated that Nitrosomonas and Candidatus Kuenenia stuttgartiensis predominated in the two reactors, and a small amount of Nitrobacter existed in R1. Thus, the reactor fed with high ammonia performed a stronger stability.