Insight into response mechanism of aerobic granular sludge to combined nanoparticle stress: Nitrogen removal, microbial community and heavy metal resistance genes

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-09, Vol.496, p.154327, Article 154327
• Main Authors: Li, Yu-Qi, Zhao, Bai-Hang, Zhang, Yu-Qing, Yang, Hai-Shan, Zhang, Bing-Lin
• Format: Article
• Language: English
• Subjects: Aerobic granular sludge (AGS); Copper oxide nanoparticles (nCuO); Heavy metal resistance genes (HMRGs); Microbial community; Zinc oxide nanoparticles (nZnO)
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.154327

[Display omitted] •Acute combined stress of nCuO and nZnO performed antagonistic inhibition.•nCuO reduced the toxicity of nZnO to nitrogen removal and membrane integrity.•nCuO mitigated the inhibition of nZnO to the expression of key functional genes.•nCuO and nZnO combined stress promoted the efferent of Zn(II) from cells. Multiple nanoparticles presented in wastewater treatment plants can produce comprehensive ecotoxicity. In this study, copper oxide nanoparticles (nCuO) and zinc oxide nanoparticles (nZnO) were investigated for their co-toxicity to aerobic granular sludge (AGS) systems. The combined stress of nCuO and nZnO performed significant antagonistic effects on nitrogen removal both under acute and chronic stress. Under chronic stress, nCuO and nZnO co-existence performed significant antagonistic effects on cell membrane, adenosine triphosphate (ATP) activity and microbial community structure. PICRUSt analysis indicated that nCuO (15 mg/L) co-existence alleviated nZnO (10 mg/L) inhibition on energy production and membrane transport metabolic pathways. In addition, nCuO addition to single nZnO weakened the toxicity of nZnO to nitrogen metabolism, glucose metabolism, and electron transfer genes, contributing to an alleviation in nitrogen removal inhibition. As compared with individual stress, combined stress decreased Cu(II) release from nCuO, but increased Zn(II) release from nZnO. The combination of nCuO and nZnO increased zinc resistance gene amplification and czcC gene proportion, and promoted Zn(II) efferent from cells, also with AGS resistance.