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The treatment performance of vertical flow constructed wetlands (VFCWs),in terms of both organic pollutants and nitrogen,is heavily dependent on oxygen supply and influent strength.In this study,the effect of influent strengths on the removal efficiencies of organic pollutants and nitrogen were investigated in VFCWs with and without intermittent aeration.The dissolved oxygen (DO) profile showed that the intermittent aeration strategy not only significantly increased the DO concentration,resulting in better removal efficiencies of organic pollutants and ammonium nitrogen (NH4+-N),but also successfully created alternate aerobic and anaerobic conditions favoring total nitrogen (TN) removal via nitrification and denitrification.Accordingly,compared with non-aerated VFCWs,the intermittent aerated VFCWs exhibited much higher removal efficiencies of organic pollutants in terms of chemical oxygen demand (COD),ammonium nitrogen (NH4+-N),and total nitrogen (TN),all above 90% except TN (more than 85%),especially at high influent strengths.The removal efficiencies of both organic pollutants and nitrogen were found to be unsatisfactory in non-aerated VFCWs especially in higher influent strength as a result of oxygen limitation.It appears that the intermittent aeration would be a valuable strategy for further increasing the treatment efficiencies and thus expanding the application of VFCWs,especially for the in-situ treatment of high strength decentralized domestic wastewaters.