Distribution characteristics and removal rate of antibiotics and antibiotic resistance genes in different treatment processes of two drinking water plants

Emerging pollutants, such as antibiotics and antibiotic-resistance genes, are becoming increasingly important sources of safety and health concerns. Drinking water safety, which is closely related to human health, should receive more attention than natural water body safety. However, minimal research has been performed on the efficacy of existing treatment processes in water treatment plants for the removal of antibiotics and antibiotic resistance genes. To address this research gap, this study detected and analyzed six main antibiotics and nine antibiotic resistance genes in the treatment processes of two drinking water plants in Wuhan. Samples were collected over three months and then detected and analyzed using ultra-high-performance liquid chromatography-tandem mass spectrometry and fluorescence quantitation. The total concentrations of antibiotics and antibiotic resistance genes in the influent water of the two water plants were characterized as December > March > June. The precipitation and filtration processes of the Zou Maling Water Plant and Yu Shidun Water Plant successfully removed the antibiotics. The ozone-activated carbon process increased the removal rate of most antibiotics to 100%. However, a large amount of antibiotic resistance gene residues remained in the effluents of the two water plants. The experiments demonstrated that the existing ozone-activated carbon processes could not effectively remove antibiotic resistance genes. This study provides a reference for the optimization of drinking water treatment processes for antibiotics and antibiotic resistance gene removal.