The aerobic granular sludge (AGS) technology has shown a great potential for effectively removing oxytetracycline (OTC) from wastewater in an environmentally friendly way. In this study, the removal mechanism of OTC by the AGS process was investigated. The results showed that AGS has adsorption behavior to OTC and biodegradation at the same time. The adsorption process of OTC by AGS that before acclimation fits the pseudo-second-order kinetic model and the adsorption process by AGS that after acclimation complied well with the pseudo-first-order kinetic model. The adsorption included the boundary layer diffusion, the diffusion of OTC in AGS pores, and the adsorption of OTC on the inner surface of AGS. The adsorption capacity of AGS to OTC was affected by the mixed liquor suspended solids (MLSS) concentration of AGS. When the AGS concentration was 10 g/L MLSS, the adsorption effects of AGS on OTC were better. AGS showed outstanding biodegradation abilities after its adaptation to OTC, and the biodegradation ratio of AGS to OTC was 77%. Thirteen kinds of intermediate products formed during OTC degradation were detected, and accordingly, the biodegradation pathway of OTC was constructed. The results will promote the wide application of AGS biological treatment technology.

好氧颗粒污泥（AGS）技术显示了巨大的潜力，可以以环保的方式有效地从废水中去除土霉素。在这项研究中，研究了通过AGS工艺去除OTC的机理。结果表明，AGS同时具有对OTC的吸附行为和生物降解作用。驯化前AGS对OTC的吸附过程符合拟二阶动力学模型，驯化后AGS对OTC的吸附过程与拟一阶动力学模型很好地吻合。吸附包括边界层扩散，OTC在AGS孔中的扩散以及OTC在AGS内表面上的吸附。AGS对OTC的吸附能力受AGS混合液悬浮固体（MLSS）浓度的影响。当AGS浓度为10 g / L MLSS时，AGS对OTC的吸附效果更好。AGS适应OTC后具有出色的生物降解能力，AGS对OTC的生物降解率为77％。检测了13种OTC降解过程中形成的中间产物，从而构建了OTC的生物降解途径。结果将促进AGS生物处理技术的广泛应用。