Occurrence and removal of quinolone, tetracycline, and macrolide antibiotics from urban wastewater in constructed wetlands

Constructed wetlands (CWs) are potentially effective for the removal of antibiotics, yet the inherent process and mechanism of antibiotic removal remain insufficiently elucidated. This study investigated the removals of eight antibiotics (norfloxacin, ciprofloxacin, lomefloxacin, ofloxacin, tetracycline, oxytetracycline, erythromycin, roxithromycin) from domestic sewage in CWs of different flow types, substrates, plants, and hydraulic loading rates in two seasons. The results showed that the CWs performed efficiently for treating antibiotic contaminated urban wastewater. Flow type deciding redox condition is the domain factor of antibiotic removal through affecting methanogenic degradation. Photolysis is significant in half-substrate systems during summer with exposure to strong sunlight, while adsorption is noteworthy in full-substrate systems during winter with cold weather. Furthermore, plant presence may limit the anaerobic processes of antibiotics via radial oxygen loss. (C) 2019 Elsevier Ltd. All rights reserved.