Fate and removal of antibiotics and antibiotic resistance genes in hybrid constructed wetlands

Hybrid design and artificial aeration has been widely applied in wetlands, but little is known about their effectiveness in the removal of antibiotics and antibiotic resistance genes (ARGs). Here we investigated the performance of various mesocosm-scale constructed wetlands (CWs) with artificial aeration and hybrid design in removal of antibiotics and ARGs from antibiotics-spiked domestic sewage. Four hybrid constructed wetland systems with zeolite as substrate and Iris tectorum Maxim as plant were set up to have different artificial aeration designs. The aqueous removal efficiencies of total antibiotics ranged from 87.4% to 95.3%, while those of total ARGs varied from 87.8% to 99.1%. The mass removal of antibiotics by the CWs was attributed mainly to the microbial degradation. The present study imply that sorption of substrates and biological processes could be the two main mechanisms for ARGs elimination. The results from this study showed the hybrid CWs with artificial aeration could enhance treatment efficiencies of antibiotics and ARGs as well as conventional pollutants.