The Inhibition of Engineered Nano-ZnO in the Biological Nitrogen Removal Process: A Review

Abstract

Engineered nano-ZnO is extensively utilized in both production and daily life, leading to its inevitable entry into the wastewater treatment system through various pathways. Nitrogen removal microorganisms in wastewater treatment systems are highly susceptible to environmental impacts. The antibacterial properties of nano-ZnO can impede the biological nitrogen removal (BNR) process and adversely affect the nitrogen removal performance. A comprehensive understanding of the inhibitory effect and mechanism of nano-ZnO on the BNR process is crucial in devising appropriate countermeasures to ensure optimal nitrogen removal performance. This review provides an overview of the sources of nano-ZnO in the environment, its impact on the BNR process, and the inhibition mechanism, and proposes potential methods that can mitigate the inhibitory effect of nano-ZnO. Additionally, future prospects are also discussed. This review serves as a foundation for a deeper understanding of the inhibition of engineered nano-ZnO on the BNR process and aids in guiding efforts to maintain the nitrogen removal performance in the presence of engineered nano-ZnO.