Occurrence and fate of antibiotics and ARGs in a wastewater treatment plant with JHB process in Guangzhou, South China: Removal performance, interaction and host analysis

Abstract

Wastewater treatment plants (WWTPs) are recognized as sinks for antibiotics and sources of antibiotic resistance genes (ARGs). Thus, it is crucial to understand the occurrence and fate of antibiotics and ARGs in each treatment unit to propose an optimal regulation strategy for pollution control. In this study, the occurrence and fate of antibiotics and ARGs in a WWTP from Guangzhou, southern China with Johannesburg (JHB) process, a common WWTP treatment technique in China, were investigated. Occurrence and fate of a total of 17 common antibiotics and 14 ARGs types were determined in each treatment unit in the WWTP. The contribution of each treatment unit to the total removal efficiency of antibiotics and ARGs in the WWTP were investigated. Although a high removal rate (95.32 %) was observed for total antibiotics, risk quotient (RQ) analysis showed that chloramphenicol in effluent still presented notable ecological risk. We further found that disinfection dramatically increased ARGs abundance and risk of horizontal gene transfer (HGT). Contribution of various environmental factors to microbial community structure and ARGs variation were also quantified with variation partitioning analysis (VPA). Co-occurrence network analysis further revealed the potential hosts of ARGs. This study contributed to a specific understanding of the fate of antibiotics and ARGs within the WWTP with JHB process and provided insight into the removal of antibiotics and ARGs in the wastewater.