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Insight into the impact of Fe3O4 nanoparticles on anammox process of subsurface-flow constructed wetlands under long-term exposure

Li, Huai, Chi, Zifang, Yan, Baixing
Environmental science and pollution research international 2018 v.25 no.29 pp. 29584-29592
Desulfosporosinus, Exiguobacterium, anaerobic ammonium oxidation, cell membranes, cell movement, chronic exposure, constructed wetlands, gene expression regulation, genes, iron oxides, lipids, metabolism, nanoparticles, nitrogen content, subsurface flow, wastewater treatment
The increasing use of Fe₃O₄ nanoparticles (NPs) had posed an emerging challenge to wastewater treatment processes, and their potential impact on anaerobic ammonium oxidation (anammox) process of unplanted subsurface-flow constructed wetlands (USFCWs) was investigated firstly under the long-term exposure of different Fe₃O₄ NP concentrations. It was found that Fe₃O₄ NP exposure could improve total nitrogen (TN) removal. The abundance of Candidatus Anammoxoglobus increased significantly at 10 mg/L Fe₃O₄ NPs, while decreased under 1 mg/L Fe₃O₄ NP exposure. Desulfosporosinus and Exiguobacterium increased to some extent at 1 mg/L Fe₃O₄ NPs, suggesting that Fe-anammox played an important role in TN removal. The ROS production increased with the increase of Fe₃O₄ NP concentration, and the integrity of cell membrane was good under Fe₃O₄ NP exposure. The functional genes that related to inorganic ion transport and metabolism and lipid transport and metabolism were upregulated, and cell motility decreased after long-term exposure of 1 mg/L Fe₃O₄ NPs. Graphical abstract ᅟ