Impact of tetracycline on the performance and abundance of functional bacteria of a lab-scale anaerobic-aerobic wastewater treatment system

The occurrence of various antibiotics in wastewater treatment systems continues to arouse extensive attention. However, the effects of low concentration of antibiotics on wastewater treatment performance and the related functional bacteria, especially under long-term operation, remain largely unknown. In this study, a lab-scale anaerobic-aerobic system was established to evaluate the impacts of 5 mg l(-1) tetracycline on the performance of a lab-scale wastewater treatment system and the abundance of the related functional bacteria. The results indicated that Tc exposure had little effect (p > 0.05) on the efficiency of COD removal during the whole period of 200 days, but significantly decreased ammonia removal (p <0.05) and accelerated sludge bulking deterioration. Although the core bacterial communities and the abundance of amoA genes in the activated sludge were not affected, the growth of Nitrospira was inhibited (p < 0.05), and Sphaerotilus was promoted by tetracycline exposure. The results of this study provide important references for the maintenance of wastewater treatment systems. (C) 2018 Elsevier B.V. All rights reserved.