摘要
      在低温下实现稳定的颗粒化和操作已成为好氧颗粒污泥（AGS）应用的挑战。废水中抗生素的出现可能会加剧这一挑战，但相关信息仍然缺乏。在此，我们研究了不同浓度（分别在RC、RL和RH反应器中为0、10和1000μg/L）的抗生素磺胺嘧啶（SDZ）是否以及如何在季节性温度从25°C降至10°C时影响AGS系统。结果表明，所有反应器都经历了颗粒形成、崩解和回收的过程，SDZ对AGS具有兴奋作用。在反应器中，RL颗粒化最快，颗粒结构最稳定，而RH颗粒形成最慢，颗粒崩解最严重。SDZ对颗粒沉降性、密度和生物量以及脱氮性能表现出低水平的刺激和高水平的抑制。RH初始启动阶段细胞外聚合物（EPS）含量较低可能与造粒延迟有关。而RH中功能属硝化单胞菌和Ca.Nittrotoga的丰度较低可以解释脱氮的恶化。宏基因组分析进一步揭示了RH中更高丰度的抗性体和移动体，主要归因于SDZ相应抗性基因（sul1和sul2）和转座酶（tnpA）的富集。磺酰胺抗性基因的丰度主要由获得性抗生素抗性基因（ARGs）贡献，这表明ARGs在AGS微生物中交换的潜力很高。这项研究为抗生素在降低温度下对AGS的影响提供了新的见解。
Abstract
Achieving stable granulation and operation at decreasing temperature has become a challenge for application of aerobic granular sludge (AGS). Antibiotic occurrence in wastewater may exacerbate the challenge, but relevant information is still lacking. Herein, we investigated whether and how the antibiotic sulfadiazine (SDZ) at different concentrations (0, 10, and 1000 μg/L in reactors RC, RL and RH, respectively) influencing AGS systems at seasonal temperature decrease from 25 to 10 °C. Results showed that all reactors experienced processes of granule formation, disintegration and recovery, and the SDZ had hormesis effects on AGS. Among the reactors, RL showed the fastest granulation and possessed the most stable granule structure, whereas RH obtained the slowest granule formation and had the severest granule disintegration. The SDZ exhibited low-level stimulation and high-level suppression on granule settleability, density and biomass, as well as nitrogen removal performance. Lower amount of extracellular polymeric substances (EPS) during initial start-up stage in RH could be related to the delay in granulation. While lower abundance of functional genera Nitrosomonas and Ca. Nitrotoga in RH could explain the deterioration in nitrogen removal. Metagenomic analysis further revealed higher abundances of resistome and mobilome in RH, mainly attributed to the enrichment of SDZ-corresponding resistance genes (sul1 and sul2) and transposases (tnpA), respectively. The abundance of sulfonamide resistance genes was mainly contributed by acquired antibiotic resistance genes (ARGs), indicating high potential for ARGs exchange in AGS microbes. This study provides novel insights into the effects of antibiotics on AGS at decreasing temperature.

https://www.sciencedirect.com/science/article/abs/pii/S1385894721043096