Transient disturbance of engineered ZnO nanoparticles enhances the resistance and resilience of anammox process in wastewater treatment

Publication date: 1 May 2018
Source:Science of The Total Environment, Volumes 622–623
Author(s): Zheng-Zhe Zhang, Ya-Fei Cheng, Lian-Zeng-Ji Xu, Yu-Hui Bai, Jia-Jia Xu, Zhi-Jian Shi, Qian-Qian Zhang, Ren-Cun Jin
The increasing use of engineered nanoparticles (NPs) in consumer and industrial products raises concerns about their environmental impacts, but their potential influence on anaerobic ammonium oxidation (anammox) process in wastewater treatment remains unknown. In this study, the response of granule-based anammox reactor to different loads of ZnONPs was investigated. The introduction of 1–5mgL⁻¹ ZnONPs did not affect reactor performance, but 90% of the nitrogen removal capacity was deprived by a shock of 10mgL⁻¹ ZnONPs within 3days. Anammox activity was significantly inhibited, but no significant stimulation of intracellular reactive oxygen species (ROS) production or extracellular lactate dehydrogenase (LDH) activity was observed. The inhibition was thus mainly due to the accumulation of toxic Zn(II) ions in anammox biomass. However, the resistance and resilience of this anammox reactor to ZnONPs were enhanced by intermittent perturbations in the mode of "shock-recovery". The up-regulated abundance of Zn(II)-exporter ZntA might contribute to the enhanced resistance. In addition, these repeated transient disturbances improved the functional specificity of the anammox community despite the reduction of its diversity. Overall, these results may provide useful references for evaluating and controlling the risk of NPs to anammox process.

Graphical abstract

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