Enhancing antibiotic removal in constructed wetlands: A MgFe-LDHs-based strategy for optimizing microbial communities...

To efficiently remove antibiotics from domestic and livestock wastewater in southern China, vertical flow constructed wetlands (CWs) were designed with and without magnesium-iron layered double hydroxides (MgFe-LDHs). Their removal efficiencies for three typical antibiotics (tetracycline, oxytetracycline, and ofloxacin) were evaluated. Results showed that MgFe-LDHs significantly improved nitrogen and phosphorus removal (18.7 %-25.6 %) and enhanced the degradation of tetracycline, oxytetracycline, and ofloxacin (13.1 %-17.8 %). High-resolution LC-MS analysis indicated significant biodegradation through various pathways, such as oxidation, hydrolysis, and dealkylation. Analysis of the Shannon diversity index demonstrated that the introduction of novel MgFe-LDHs enhanced microbial diversity and evenness at the phylum, class, and genus levels. The introduction of MgFe-LDHs increased microbial diversity and enriched antibiotic-degrading genera like Xanthobacter, Ochrobactrum, and Stenotrophomonas. Moreover, MgFe-LDHs may have enhanced the metabolic pathways of glycolysis and the tricarboxylic acid cycle, thereby improving the microbial degradation of organic matter. In summary, MgFe-LDHs exhibited a multifaceted role in enhancing antibiotic removal in CWs by inducing the enrichment of antibiotic-degrading bacteria and regulating the metabolic functions of the microbial community, while also ensuring higher nitrogen and phosphorus removal efficiency.