Department of Municipal Engineering, School of Civil Engineering, Guangzhou University, Guangzhou, 510006, China; Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.
Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.
J Hazard Mater. 2019 Dec 15;380:120894. doi: 10.1016/j.jhazmat.2019.120894. Epub 2019 Jul 13.
A lab-scale mesophilic anaerobic membrane bioreactor (AnMBR) was used to treat synthetic municipal wastewater with variable concentrations of antibiotic Sulfamethoxazole (SMX) and bulk organics in this study. The removal and biotransformation pathway of SMX in the AnMBR were systematically investigated during a 170 d of operation under hydraulic retention time of 1 d. Average SMX removal was 97.1% under feed SMX of 10-1000 μg/L, decreasing to 91.6 and 88.0% under feed SMX of 10,000 and 100,000 μg/L due to the inhibition effects of high SMX loading rate on anaerobic microorganisms. SMX biotransformation followed pseudo-first order reaction kinetics based on SMX removal independent of feed SMX of 10-1000 μg/L during continuous operation and also in a batch test under initial SMX of 100,000 μg/L. According to the identified 7 transformation products (TPs) by gas chromatography-mass spectrometry, the biotransformation pathway of SMX from municipal wastewater treatment via AnMBR was first proposed to consist of 2 primary routes: 1) Butylbenzenesulfonamide without antibiotic toxicity dominated under feed SMX of 10-100 μg/L; 2) Sulfanilamide with much lower antibiotic toxicity than SMX dominated under feed SMX of 1000-100000 μg/L, further transforming to secondary TPs (4-Aminothiophenol, Aniline, Acetylsulfanilamide) and tertiary TPs (4-Acetylaminothiophenol, Acetylaniline).
本研究采用实验室规模的中温厌氧膜生物反应器（AnMBR），在水力停留时间为 1 天的条件下，处理含有不同浓度抗生素磺胺甲恶唑（SMX）和大量有机物的合成城市废水。在 170 天的运行过程中，系统研究了 AnMBR 中 SMX 的去除和生物转化途径。在进料 SMX 为 10-1000μg/L 的条件下，SMX 的平均去除率为 97.1%，而在进料 SMX 为 10000 和 100000μg/L 的条件下，由于高 SMX 加载率对厌氧微生物的抑制作用，SMX 的去除率分别降低至 91.6%和 88.0%。SMX 的生物转化遵循伪一级反应动力学，与连续运行过程中进料 SMX 为 10-1000μg/L 时的 SMX 去除无关，也与初始 SMX 为 100000μg/L 时的批处理试验一致。根据气相色谱-质谱法鉴定的 7 种转化产物（TPs），首次提出了 AnMBR 处理城市污水中 SMX 的生物转化途径由 2 条主要途径组成：1）在进料 SMX 为 10-100μg/L 时，主要生成无抗生素毒性的丁基苯磺酰胺；2）在进料 SMX 为 1000-100000μg/L 时，主要生成抗生素毒性比 SMX 低得多的磺胺，进一步转化为次级 TPs（4-氨基噻吩酚、苯胺、乙酰磺胺）和三级 TPs（4-乙酰氨基噻吩酚、乙酰苯胺）。
