Insights into the fate of antibiotics in constructed wetland systems: Removal performance and mechanisms

Antibiotics have been recognized as emerging contaminants that are widely distributed and accumulated in aquatic environment, posing a risk to ecosystem at trace level. Constructed wetlands (CWs) have been regarded as a sustainable and cost-effective alternative for efficient elimination of antibiotics. This review summarizes the removal of 5 categories of widely used antibiotics in CWs, and discusses the roles of the key components in CW system, i.e., substrate, macrophytes, and microorganisms, in removing antibiotics. Overall, the vertical subsur-face flow CWs have proven to perform better in terms of antibiotic removal (>78%) compared to other single CWs. The adsorption behavior of antibiotics in wetland substrates is determined by the physicochemical prop-erties of antibiotics, substrate configuration and operating parameters. The effects of wetland plants on antibiotic removal mainly include direct (e.g., plant uptake and degradation) and indirect (e.g., rhizosphere processes) manners. The possible interactions between microorganisms and antibiotics include biosorption, bio-accumulation and biodegradation. The potential strategies for further enhancement of the antibiotic removal performance in CWs included optimizing operation parameters, innovating substrate, strengthening microbial activity, and integrating with other treatment technologies. Taken together, this review provides useful infor-mation for facilitating the development of feasible, innovative and intensive antibiotic removal technologies in CWs, as well as enhancing the economic viability and ecological sustainability.

Automated summary

This review summarizes the removal of widely used antibiotics in constructed wetlands (CWs) and discusses the roles of substrate, macrophytes, and microorganisms in removing antibiotics. Vertical subsurface flow CWs have shown better performance in antibiotic removal. The adsorption behavior of antibiotics in wetland substrates is influenced by their physicochemical properties, substrate configuration, and operating parameters. Wetland plants can directly and indirectly affect antibiotic removal through uptake, degradation, and rhizosphere processes. Microorganisms can interact with antibiotics through biosorption, bioaccumulation, and biodegradation. Strategies for further enhancing antibiotic removal in CWs include optimizing operation parameters, innovating substrate, strengthening microbial activity, and integrating with other treatment technologies.