Effects of Aeration on the Formation of Arbuscular Mycorrhiza under a Flooded State and Copper Oxide Nanoparticle Removal in Vertical Flow Constructed Wetlands.

In this study, six vertical flow constructed wetlands (VFCWs) planted with Phragmites australis were operated at different aeration times (4 h day-1 and 8 h day-1), aeration modes (continuous and intermittent), and arbuscular mycorrhizal fungi (AMF) inoculation treatments (inoculation with Rhizophagus intraradices and no inoculation) to explore the effects of different aeration strategies on the formation of arbuscular mycorrhiza under a flooded state in VFCWs. In addition, these VFCWs were further used to treat copper oxide nanoparticle (CuO-NP) wastewater to evaluate the correlations among aeration, colonization, growth, and CuO-NP removal. The highest AMF 28S copy number (1.99×105) and colonization in reed roots, with values of 67%, 21%, and 1% for frequency (F%), intensity (M%), and arbuscule abundance (A%), were observed in the treatment with intermittent aeration for 4 h day-1. Aeration significantly increased the dissolved oxygen (DO) concentration and AMF colonization in VFCWs, thereby promoting plant growth and the purification of the CuO-NPs. However, excessive and continuous aeration had little positive effect on AMF colonization. This study provides a theoretical basis for the application of AMF for improving pollutant removal performance in constructed wetlands.