Removal of Antibiotics and Antibiotic Resistance Genes from Domestic Sewage by a Subsurface Wastewater Infiltration System with Long-Term Operations

摘要

Antibiotics and antibiotic resistance genes (ARGs), which are regarded as emerging environmental contaminants due to their potential threat to human health and ecological systems, cannot be effectively removed from sewage by most conventional wastewater treatment plants. As an environmental-friendly and cost-efficient technology, subsurface wastewater infiltration systems (SWISs) can reduce the concentration of conventional pollutants significantly. However, the performance of SWISs on antibiotics and ARGs' removal is totally unknown. Therefore, we constructed a pilot-scale aerobic SWIS, and investigated its removal ability on antibiotics and ARGs while the system was operated for as long as 29 months at a hydraulic loading rate of 0.5 m(3)/(m(2) center dot day). Results showed that 14 antibiotics and 12 target genes were detected in influents, with total concentrations of 416-9642.15 ng/L for antibiotics and (1.32 +/- 0.19) x 10(7) to (2.21 +/- 0.18) x 10(8) copies/mL for ARGs. After being treated by the SWIS, total antibiotics and ARGs in effluents declined by 92.46-99.73% and 99.92-100%, respectively. In terms of the removal mechanism, biodegradation was considered as the primary contribution and substrate adsorption as the secondary contribution. Our findings indicated that the upgraded SWIS could be an attractive technology for domestic sewage treatment in dealing with emerging contaminants, such as antibiotics and ARGs.