Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, CDMX, México.
Departmento de Recursos de la Tierra, Universidad Autónoma Metropolitana-Lerma, Lerma, México.
Environ Technol. 2021 Jul;42(18):2815-2822. doi: 10.1080/09593330.2020.1714746. Epub 2020 Jan 23.
Metronidazole is potentially carcinogenic to humans and it has been detected in wastewaters. The Wastewater Treatment Plants using biological processes have been highly impacted by the emergent compounds of recalcitrant type, and the knowledge about that issue is quite relevant. Therefore, this paper was focused on how metronidazole influences the kinetics and metabolic behaviour of nitrification and heterotrophic activity on activated sludge in batch cultures. Eight concentrations of metronidazole in the range of 5-100 mg/L were evaluated, in the presence of 2109 ± 129 mg VSS/L. The increment of initial metronidazole concentration caused a decline on COD and ammonium removal efficiencies, nitrate production yields, as well as in the substrate-specific consumption rates. Metronidazole (MDZ) had a greater impact on heterotrophic activity than nitrifying activity; also, it had a greater inhibitory effect on nitrite oxidation than ammonium oxidation. The activated sludge was not able to biotransform metronidazole; however, the azole compound significantly affected the physiology of it. The inhibition of ammonium oxidation was non-competitive (= 120 mg NH-N consumed/gVSS-d, and = 41.5 mg MDZ/L) and the initial metronidazole concentration that inhibited 50% of nitrifying activity (IC) was 43 mg MDZ/L.
甲硝唑对人类具有潜在致癌性，并且已在废水中检测到。采用生物工艺的废水处理厂受到难降解新兴化合物的高度影响，而关于该问题的知识是非常相关的。因此，本文专注于甲硝唑如何影响硝化和异养活性在批式培养中的动力学和代谢行为。评估了范围为 5-100mg/L 的 8 种甲硝唑浓度，存在 2109±129mg VSS/L。初始甲硝唑浓度的增加导致 COD 和氨氮去除效率、硝酸盐生成产率以及基质特异性消耗率下降。甲硝唑（MDZ）对异养活性的影响大于硝化活性；此外，它对亚硝酸盐氧化的抑制作用大于对氨氧化的抑制作用。活性污泥不能将甲硝唑生物转化；然而，该唑类化合物对其生理功能有显著影响。氨氧化的抑制是非竞争性的（=120mg NH-N 消耗/gVSS-d，=41.5mg MDZ/L），抑制 50%硝化活性的初始甲硝唑浓度为 43mg MDZ/L。
