Resistance to copper oxide nanoparticle and oxytetracycline of partial nitrification sludge

Nanoparticles (NPs) and antibiotics are two emerging pollutants in environment and always simultaneously exist in nitrogen-rich wastewater. In this study, the individual and joint effects of CuO NPs and oxytetracycline (OTC) on partial nitrification (PN) process were investigated in four identical reactors (1 L). Results indicated that 1 mg L −1 CuO NPs and OTC respectively improved the ammonia removal efficiency (ARE) to 68.9% and 76.6%, compared to the 62.9% in control reactor. However, the joint CuO NPs and OTC performed significant suppression on PN and decreased the ARE to 51.0%, which was due to the formative complex of CuO NPs-OTC that disordered the metabolic and inhibited the cell growth. Nitrosomonas shared 38.01% (Control), 39.7% (CuO NPs), 44.29% (OTC) and 39.81% (CuO NPs + OTC), respectively. The joint CuO NPs and OTC induced 6.1 ( tetC ), 7.4 ( tetX ), 3.6 ( tetC ) and 2.9 ( tetM ) times’ amplification of antibiotic resistance genes compared with the blank.