State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Research Center of Environmental Pollution Control Technology, Chinese Research Academy of Environmental Science, Beijing 100012, China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Research Center of Environmental Pollution Control Technology, Chinese Research Academy of Environmental Science, Beijing 100012, China.
J Environ Sci (China). 2023 Aug;130:24-36. doi: 10.1016/j.jes.2022.10.020. Epub 2022 Oct 25.
Solid-phase denitrification (SPD) has been used in wastewater treatment plant effluent to enhance nitrate removal, and antibiotics co-existing in the effluent is a common environmental problem. In this study, it was systematically investigated the effect of single trace sulfamethoxazole (SMX)/trimethoprim (TMP) and their mixture on microbial denitrification performance, the antibiotics removal, and antibiotics resistance genes (ARGs) in corncob supported SPD system. The average denitrification rate was improved by 46.90% or 61.09% with single 50 µg/L SMX or TMP, while there was no significant inhibition with mixed SMX and TMP. The abundance of dominant denitrifiers (Comamonadaceae family and Azospia) and fermentation bacteria (Ancalomicrobium) were consistent with the denitrification performance of different antibiotics groups. Single SMX and TMP achieved relatively higher denitrification gene and enzyme abundance. Mixed SMX and TMP improved the denitrification gene copies, but they reduced the key denitrification enzymes except for EC 1.7.7.2. Additionally, the removal efficiency of TMP (56.70% ± 3.18%) was higher than that of SMX (25.44% ± 2.62%) in single antibiotic group, and the existence of other antibiotics (i.e. SMX or TMP) had no significant impact on the TMP or SMX removal performance. Biodegradation was the main removal mechanism of SMX and TMP, while sludge and corncob adsorption contributed a little to their removal. SMX had the risk of sulfanilamide resistance genes (SRGs) dissemination. Furthermore, network analysis indicated that Niveibacterium and Bradyrhizobium were the potential hosts of SRGs, which promoted the horizontal transmission of ARGs.
固相反硝化（SPD）已被应用于污水处理厂出水以增强硝酸盐的去除，而抗生素在出水中共存是一个常见的环境问题。在本研究中，系统地研究了单一痕量磺胺甲恶唑（SMX）/甲氧苄啶（TMP）及其混合物对玉米芯支持的 SPD 系统中微生物反硝化性能、抗生素去除和抗生素抗性基因（ARGs）的影响。单一 50μg/L 的 SMX 或 TMP 可使平均反硝化率分别提高 46.90%或 61.09%，而混合的 SMX 和 TMP 则没有明显的抑制作用。优势反硝化菌（Comamonadaceae 科和 Azospia）和发酵菌（Ancalomicrobium）的丰度与不同抗生素组的反硝化性能一致。单一的 SMX 和 TMP 实现了相对较高的反硝化基因和酶丰度。混合的 SMX 和 TMP 提高了反硝化基因拷贝数，但除了 EC 1.7.7.2 外，它们降低了关键的反硝化酶。此外，在单一抗生素组中，TMP（56.70%±3.18%）的去除效率高于 SMX（25.44%±2.62%），而其他抗生素（即 SMX 或 TMP）的存在对 TMP 或 SMX 的去除性能没有显著影响。生物降解是 SMX 和 TMP 的主要去除机制，而污泥和玉米芯吸附对其去除作用较小。SMX 有磺胺类抗性基因（SRGs）传播的风险。此外，网络分析表明，Niveibacterium 和 Bradyrhizobium 是 SRGs 的潜在宿主，促进了 ARGs 的水平传播。
