摘要
      为了了解生物滞留系统在磺胺甲恶唑（SMX）胁迫下的长期性能，建立了一个未接种的生物滞留系统（BRS）和两个用椰子壳活性炭（CAC）和CAC/零价铁（Fe0）颗粒（CAC-BRS和Fe/CAC-BRS）修饰的生物滞留系统。在长期SMX暴露（0.8 mg/L，205天）下，CAC-BRS和Fe/CAC-BRS在去除总氮（TN）（CAC-BRS:82.48%；Fe/CAC-BS:78.08%；BRS:47.51%）、总磷（TP）（CAC-BRS:79.36%；Fe/CAC-BRS:98.26%；BRS:11.99%）和SMX（CAC-BRS:99.74%，Fe/CAC-SR:99.80%；BRS:23.05%）方面均显著优于BRS。高通量测序显示，暴露于SMX后，三种BRS的微生物群落结构在上部区域发生了巨大变化。将FAPROTAX数据库的功能预测与优势属相结合，确定了关键功能属，主要为硝化螺旋菌属、Rhodoplanes属、脱硫微生物属、地杆菌属。CAC-BRS和Fe/CAC-BRS中氮功能基因（nirK、nirS和nosZ）的丰度较高，这可能解释了这两个系统中TN去除效率较高的原因。此外，在所有BRS中，抗生素抗性基因（ARGs）sulI和sulII的相对丰度随着SMX暴露而增加，这表明选择了含有sul基因的细菌。底物往往成为sul基因的库。此外，共现网络分析揭示了上部和下部区域之间ARG的不同潜在宿主属。值得注意的是，Fe/CAC-BRS成功地将流出物sul基因减少了1-2个数量级，其次是暴露205天后的CAC-BRS。这项研究表明，基质改性对于保持高效的营养物质和SMX去除至关重要，并最终延长BRS在处理SMX废水中的使用寿命。
Abstract
To understand the long-term performance of bioretention systems under sulfamethoxazole (SMX) stress, an unplanted bioretention system (BRS) and two modified BRSs with coconut-shell activated carbon (CAC) and CAC/zero-valent-iron (Fe0) granules (CAC-BRS and Fe/CAC-BRS) were established. Both CAC-BRS and Fe/CAC-BRS significantly outperformed BRS in removing total nitrogen (TN) (CAC-BRS: 82.48%; Fe/CAC-BRS: 78.08%; BRS: 47.51%), total phosphorous (TP) (CAC-BRS: 79.36%; Fe/CAC-BRS: 98.26%; BRS: 41.99%), and SMX (CAC-BRS: 99.74%, Fe/CAC-BRS: 99.80%; BRS: 23.05%) under the long-term SMX exposure (0.8 mg/L, 205 days). High-throughput sequencing revealed that the microbial community structures of the three BRSs shifted greatly in upper zones after SMX exposure. Key functional genera, dominantly Nitrospira, Rhodoplanes, Desulfomicrobium, Geobacter, were identified by combining the functional prediction by the FAPROTAX database with the dominant genera. The higher abundance of nitrogen functional genes (nirK, nirS and nosZ) in CAC-BRS and Fe/CAC-BRS might explain the more efficient TN removal in these two systems. Furthermore, the relative abundance of antibiotic-resistant genes (ARGs) sulI and sulII increased in all BRSs along with SMX exposure, suggesting the selection of bacteria containing sul genes. Substrates tended to become reservoirs of sul genes. Also, co-occurrence network analysis revealed distinct potential host genera of ARGs between upper and lower zones. Notably, Fe/CAC-BRS succeeded to reduce the effluent sul genes by 1-2 orders of magnitude, followed by CAC-BRS after 205-day exposure. This study demonstrated that substrate modification was crucial to maintain highly efficient nutrients and SMX removals, and ultimately extend the service life of BRSs in treating SMX wastewater.

https://www.sciencedirect.com/science/article/abs/pii/S1001074222001681