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Long-term effects of CeO2 NPs on the biological phosphorus removal mechanism of DPR-AGS in A/O/A SBRs

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Abstract

The increasing use of cerium dioxide nanoparticles (CeO2 NPs) has raised concerns about their potential environmental toxicity. Denitrifying phosphorus removal-aerobic granular sludge (DPR-AGS) is a distinct form of microbial aggregates. In this study, the phosphorus removal efficiencies, the metabolic intermediates of polyhydroxyalkanoates (PHA) and glycogen, the enzyme activities of exophosphatase (PPX) and polyphosphate kinase (PPK), and the microbial community of DPR-AGS under long-term exposure to CeO2 NPs (0 (the control), 1, and 10 mg L−1) in anaerobic/oxic/anoxic (A/O/A) sequencing batch reactors (SBRs) were investigated. The results showed that chronic toxicity caused by 10 mg L−1 CeO2 NPs resulted in increased reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) release, which reached 176.32% and 237.35%, respectively, when compared with the control (100%). High-throughput sequencing showed that denitrifying-phosphorus-accumulating organisms (DPAOs) were more sensitive to CeO2 NPs than phosphorus-accumulating organisms (PAOs), which was in accordance with phosphorus transformations during one cycle. However, the abundance of Dechloromonas and Defluviicoccus increased from 4.68% and 3.08% (R0) to 9.95% and 7.06% (R10), respectively, indicating that the tolerance of glycogen-accumulating organisms to CeO2 NPs was stronger than that of PAOs, which was consistent with the transformation of the metabolic pathway from polyphosphate accumulation (PAM) to glycogen accumulation (GAM).

Graphical abstract: Long-term effects of CeO2 NPs on the biological phosphorus removal mechanism of DPR-AGS in A/O/A SBRs

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Publication details

The article was received on 27 Jul 2018, accepted on 20 Oct 2018 and first published on 22 Oct 2018


Article type: Paper
DOI: 10.1039/C8EN00820E
Citation: Environ. Sci.: Nano, 2018, Advance Article
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    Long-term effects of CeO2 NPs on the biological phosphorus removal mechanism of DPR-AGS in A/O/A SBRs

    X. Zheng, D. Lu, Y. Zhang, W. Chen, M. Jin, X. Shao and M. Yang, Environ. Sci.: Nano, 2018, Advance Article , DOI: 10.1039/C8EN00820E

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