Roles of substrates in removing antibiotics and antibiotic resistance genes in constructed wetlands: A review

• Published in: The Science of the total environment Vol. 859; no. Pt 1; p. 160257
• Main Authors: Cui, Erping, Zhou, Zhenchao, Gao, Feng, Chen, Hong, Li, Jianan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 10.02.2023
• Subjects: adsorption; Anti-Bacterial Agents; antibiotic resistance; Antibiotic resistance genes; Antibiotics; biodegradation; biomass; Constructed wetlands; cost effectiveness; Drug Resistance, Microbial - genetics; environment; filtration; gravel; human health; Humans; oxidation; photolysis; Removal; sand; soil; Substrates; Waste Disposal, Fluid; wastewater; Water Pollutants, Chemical - analysis; Wetlands; Zeolites; iARGs; Removal; Mn; pka; Log Kow; HRT; Al; eARGs; IF-CWs; HLR; Zn; Constructed wetlands; SF-CWs; HSSF-CWs; eDNA; MBQ; Antibiotic resistance genes; VSSF-CWs; iDNA; Fe; ARGs; DOM; WWTPs; Substrates; HGT; LECA; Antibiotics; SOS; ROS; Kd; Mg; CWs; Ca
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.160257

Antibiotics and corresponding antibiotic resistance genes (ARGs) are emerging pollutants in wastewater that pose a significant threat to the environment and human health. Constructed wetlands (CWs) are a cost-effective technology for eliminating these pollutants through substrates, plants, and microorganisms. Detailed reviews of the roles of CW substrates on antibiotic and ARG removal and recent progress in the field are lacking. This paper reviews the mechanisms influencing antibiotic and ARG (intracellular and extracellular) removal in CWs, and natural, biomass, chemical, modified, industrial, novel, and combined substrates on their removal efficiencies. Generally, substrates remove antibiotics and ARGs mainly through adsorption, biodegradation, chemical oxidation, and filtration. Other mechanisms, such as photolysis, may also contribute to removal. Natural substrates (e.g., gravel, zeolite) are more frequently employed than other types of substrates. The removal performance of antibiotics and intracellular ARGs by zeolite was better than that of gravel through enhanced substrate adsorption, filtration, and biodegradation processes. Moreover, Mn ore showed promising high capability to remove high concentration of antibiotics through various removal pathways. In addition, combined substrates of soil/sand/gravel and other substrates further facilitate antibiotic removal. Future research is suggested to explore the mechanisms of competitive adsorption and redox-controlled biodegradation, investigate the effect of Fe/Mn oxides on the removal of antibiotics and ARGs via chemical oxidation, evaluate the removal of extracellular ARGs by CWs with different substrates, and investigate the effect of substrates on removal of antibiotics and ARGs in full-scale CWs. [Display omitted] •Roles and performance of CW substrates in removing antibiotics and ARGs•Main mechanisms are adsorption, biodegradation, chemical oxidation, and filtration.•Natural substrates are more commonly used than other types of substrates.•Mn ore showed high antibiotic removal potential due to various mechanisms.•Reported combined substrates facilitated antibiotic removal.