Assessing the efficiency of ozone-based advanced drinking water treatment processes in removing antibiotics and antibiotic-resistant genes: Pilot-scale research

With the widespread use of antibiotics, the emergence of antibiotics and antibiotic resistance genes (ARGs) poses a potential threat to public health. Drinking water plants are both the source and sink of these pollutants. In this study, we investigated and analyzed the distribution of four major types of antibiotics and ARGs in a drinking water plant with advanced treatment processes (ozone and activated carbon units) located in the central region of China. Among these treatment processes, the ozone process had significant removal effects on antibiotics and resistance genes, ranging from 15.10–91.17 % and 0.07–1.27 log, (except for ermA and qnrD) respectively. A correlation analysis of the concentrations of antibiotics and ARGs revealed a significant correlation (0.95 < r < 1) between antibiotics and ARGs, as well as between different types of ARGs. Additionally, the mechanism of ozone in the lab- and pilot-scale tests was analyzed to improve the removal capacity of ozone units for target pollutants. The experimental results showed that the removal efficiency of antibiotics and ARGs by ozone could be effectively improved by increasing the ozone dosage (5 mg/L), pH (9), and reaction time (10 min). The removal efficiency of the pollutants ranged between 36.65 % and 96.01 %. Under optimal reaction conditions, the results of the pilot-scale ozone experiment were significantly better than the actual treatment effects in drinking water plants. Our findings provide a theoretical basis for the optimization of the ozone process in actual drinking water plants.