长期储存亚硝化颗粒污泥的活化及菌群结构变化

采用无机人工配水,通过逐级提高进水氨氮负荷(0.32~0.64kg/(m³·d))和设定合适的初始游离氨浓度(3.7~7.2mg/L),在SBR反应器中对常温(24~29℃)下储存1a的亚硝化颗粒污泥(NGS)进行了活化,并使用Miseq高通量测序技术分析了污泥中微生物多样性的变化情况.结果表明,NGS的亚硝化性能可在短时间内恢复.运行8d后,反应器的氨氮去除率达到95%以上,亚硝态氮累积率超过了80%,但污泥粒径持续减小,胞外聚合物(EPS)含量明显降低.活化至第20d,NGS的氨氮比去除速率和亚硝态氮比累积速率分别达到24.6mg/(gVSS·h)、23.8mg/(gVSS·h),平均粒径稳定在0.5mm左右.在活化期间,绝大部分厌氧、异养菌属被洗脱,污泥的微生物多样性显著降低.Nitrosomonas等氨氧化菌的相对丰度由活化前的1%上升至约58%,同时,Nitrospira等硝化菌的生长受到了选择性抑制.这意味着即使经历长期的常温储存,NGS仍可作为SBR的接种污泥,实现反应器的快速启动.

Reactivation performance of nitrosation granular sludge after long-term storage and microbial community variation

The reactivation performance of nitrosation granular sludge(NGS), which had been stored at 24~29℃ for a long-term of 1a, was investigated in a sequencing batch reactor(SBR) fed with inorganic synthetic wastewater, via the gradually increasing of the influent ammonia nitrogen loading from 0.32 to 0.64kg/(m³·d) and initial concentration of free ammonia from 3.7 to 7.2mg/L. High throughput sequencing technology of Miseq was also employed to analyze the variation of microbial community before and after the reactivation. Results showed that the stored NGS could be reactivated in a short period of 8days, since the removal effciency of ammonia nitrogen and the accumulation ratio of nitrite nitrogen were higher than 95% and 80%, respectively. Meanwhile, both sludge particle size and extracellular polymer substances(EPS) contents decreased significantly. After 20days reactivation, the specific ammonia nitrogen removal rate of 24.6mg/(gVSS·h) and the specific nitrite accumulation rate of 23.8mg/(gVSS·h) were observed, while average particle size of NGS remained at 0.5mm. During this period, the microbial diversity of NGS decreased obviously, ascribed to the washing out of most of anaerobic and heterotrophic bacteria. The relative abundance of ammonia-oxidizing bacteria, such as Nitrosomonas ect., increased from 1% to 58%, and the growth of nitrite-oxidizing bacteria was inhibited selectively. It indicated that the NGS after a long-term storage could be inoculated in SBR to achieve its rapid start-up.