Fate and removal of bacteria and antibiotic resistance genes in horizontal subsurface constructed wetlands: Effect of mixed vegetation and substrate type

This study aimed to investigate the influence of cropping method and substrate type on fate removal bacterial antibiotic resistance genes (ARGs) indicators from primary wastewater by constructed wetlands (CWs) during startup maturation stages. Four small-scale CWs differing in their plantation pattern (monoculture vs. polyculture) were operated under field conditions. While for bacteria, greatest impact was stage rather than stage, ARGs, such significant at both During startup, efficiencies heterotrophic fecal coliforms, E. coli, 16S rRNA lacZ increased with operation time. At maturation, constant within range 89.2–99.4%, 93.7–98.9%, 89–98.8%, 94.1–99.6% 92.9–98.7%, respectively. The intl1, tetM, sul1, ermB total ARGs also However, they ARG configuration-dependent; ranged between 50.7%–89.4%, 85.9%–97%, 49.6%–92.9%, 58.2%–96.7% 79.9–94.3%, tuff-filled serially planted CW only one capable removing these similar high efficiency. Metagenomic analysis showed that none among most common water biofilm samples; belonged efflux transporter superfamilies. Although removed, still detected relative concentrations effluents. bacteria higher summer compared winter, season had no effect ARGs. Hence, combination serial having surface area is a potential strategy can be used improve performance CWs.