Impacts of morphological-controlled ZnO nanoarchitectures on aerobic microbial communities during real wastewater treatment in an aerobic-photocatalytic system

• Published in: Environmental pollution (1987) Vol. 259; p. 113867
• Main Authors: Chang, Jang Sen, Chong, Meng Nan, Poh, Phaik Eong, Ocon, Joey D., Md Zoqratt, Muhammad Zarul Hanifah, Lee, Sze Mei
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-04-2020
• Subjects: Antibacterial activity; Bacteria - drug effects; Microbiota - drug effects; Photocatalytic degradation; Sewage - chemistry; Sewage - microbiology; Waste Water - chemistry; Waste Water - microbiology; Wastewater treatment; Water Purification; Zinc Oxide - chemistry; Zinc Oxide - toxicity; Zn2+ ions dissolution; ZnO photocatalyst; Photocatalytic degradation; Antibacterial activity; ZnO photocatalyst; Wastewater treatment; Zn2+ ions dissolution; Zn(2+) ions dissolution
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2019.113867

This study aimed to evaluate the impacts of morphological-controlled ZnO nanoarchitectures on aerobic microbial communities during real wastewater treatment in an aerobic-photocatalytic system. Results showed that the antibacterial properties of ZnO nanoarchitectures were significantly more overwhelming than their photocatalytic properties. The inhibition of microbial activities in activated sludge by ZnO nanoarchitectures entailed an adverse effect on wastewater treatment efficiency. Subsequently, the 16S sequencing analysis were conducted to examine the impacts of ZnO nanoarchitectures on aerobic microbial communities, and found the significantly lower microbial diversity and species richness in activated sludge treated with 1D-ZnO nanorods as compared to other ZnO nanoarchitectures. Additionally, 1D-ZnO nanorods reduced the highest proportion of Proteobacteria phylum in activated sludge due to its higher proportion of active polar surfaces that facilitates Zn2+ ions dissolution. Pearson correlation coefficients showed that the experimental data obtained from COD removal efficiency and bacterial log reduction were statistically significant (p-value < 0.05), and presented a positive correlation with the concentration of Zn2+ ions. Finally, a non-parametric analysis of Friedman test and post-hoc analysis confirmed that the concentration of Zn2+ ions being released from ZnO nanoarchitectures is the main contributing factor for both the reduction in COD removal efficiency and bacterial log reduction.
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•Successful synthesis of various ZnO nanostructures through hydrothermal method.•Antibacterial ability of ZnO is more significant than its photocatalytic property.•16S gene PCR and sequencing for the aerobic microbial community in activated sludge.•1D-ZnO nanorods adversely affected microbial diversity and species richness in sludge.•Zn2+ ions dissolution is the contributing factor for treatment efficiency reduction.