连续流中氮负荷对好氧颗粒污泥的稳定性影响

研究了连续流反应器中好氧颗粒污泥（AGS）处理无机高氨氮废水的脱氮性能及稳定性。接种成熟AGS启动反应器，前55天内进水氮负荷由1.0 kgm-3d-1逐步提升至4.0 kgm-3d-1，56~125天内氮负荷逐步减小至1.4 kgm-3d-1，126~145天氮负荷再次升高至2.0 kgm-3d-1。前75天内观察到明显的颗粒破碎及污泥流失，且颗粒平均粒径不断减小。虽然多次补充接种AGS以维持系统稳定性，但前90天内颗粒的污泥容积指数（SVI）、胞外聚合物（EPS）及比耗氧速率（SOUR）剧烈波动。受疫情影响，91~109天反应器原位闲置。重新运行后AGS的理化指标逐渐趋于稳定。前45天内氨氮去除率逐渐增大至98%以上，在46~75天内迅速减少至50%左右，此后再次回升至99%以上。总无机氮去除率大部分时间处在35%~45%之间。通过污泥截留试验探索了反应器对污泥的选择性筛分效果。当沉淀池中挡板深度为27 cm时，反应器对污泥的截留率在98%以上，出水污泥粒径多为0~0.30 mm污泥。利用高通量测序分析污泥菌群组成变化。与接种AGS相比，145天时AGS中的硝化细菌属（Nitrosomonas）相对丰度明显增大，而反硝化细菌属（unclassified_Flavobacteriaceae、unclassified_Xanthomonadaceae、Thauera等）的相对丰度略有降低。

Effect of nitrogen loading rate on stability of aerobic granular sludge in continuous flow

This paper investigated the denitrification performance and stability of aerobic granular sludge (AGS) for treating inorganic wastewater with high ammonia nitrogen in a continuous flow reactor. The reactor was started by seeding with mature AGS. The influent nitrogen loading rate was gradually increased from 1.0 kgm-3d-1 to 4.0 kgm-3d-1 in the former 55 days, gradually decreased to 1.4 kgm-3d-1 in days 56~125, and then increased to 2.0 kgm-3d-1 again in days 126~145. In the former 75 days, obvious particle breakage and sludge loss were observed, and the average particle size decreased continuously. Although seed AGS was supplemented several times to maintain the stability of the system, the sludge volume index (SVI), extracellular polymeric substance (EPS) and specific oxygen uptake rate (SOUR) of the granules fluctuated sharply in the former 90 days. Affected by the epidemic, the reactor was idled in situ in days 91~109. After re-startup, the physical and chemical indexes of AGS tended to be stable gradually. The removal efficiency of NH4+-N gradually increased to more than 98% in the former 45 days, rapidly decreased to approximately 50% in days 46~75, and then rose to more than 99% again. The total inorganic nitrogen removal efficiency was between 35% and 45% in most of the days. The selective screen of sludge was investigated by sludge interception test. When the depth of the baffle in the sedimentation tank was 27 cm, the sludge retention rate of the reactor was above 98%, and the particle size of sludge in effluent was mostly between 0 and 0.30 mm. The microbial community of sludge was analyzed by high throughput sequencing. Compared with the seed AGS, the relative abundance of nitrifying bacterial genus (Nitrosomonas) in AGS on day 145 increased significantly, while the relative abundance of denitrifying bacterial genera (such as unclassified_Flavobacteriaceae, unclassified_Xanthomonadaceae and Thauera) decreased slightly.