Completely autotrophic nitrogen removal over nitrite (CANON) process was an innovative technology for nitrogen removal from wastewater. It is necessary to clear the impact of CuO nanoparticles (CuO NPs) on CANON process since the widespread utilize increased their opportunity for entering into wastewater. In this study, the short-term and long-term effects of CuO NPs on the ammonia removal and extracellular polymeric substance (EPS) secretion were analyzed in the presence of nitrite, with the CuO NPs of 0, 5, 10, 20, 50, 100, 200, and 500 mg L-1, respectively. Results suggested that low concentration of CuO NPs could enhance the ammonia removal. The inhibition threshold of CuO NPs on CANON sludge within short-term exposure was 20 mg L-1, while that of long-term exposure was 10 mg L-1. Both short-term and long-term exposure within CuO NPs significantly impacted the ammonia removal, and both the nitrite and CuO NPs influenced the EPS secretion.
Keywords: Copper oxide nanoparticles; ammonia; autotrophic nitrogen removal; extracellular polymeric substance; nitrite.