Efficient removal of tetracycline using U-type continuous-flow bioelectrochemical system without ion exchange membrane or cathodic catalyst

A U-type membraneless continuous-flow bioelectrochemical system was developed to efficiently remove tetracycline and antibiotic resistance genes from synthetic wastewaters at hydraulic retention time of only eight hours. At the TC concentration of 20–80 mgL^-1 in feed, the removals of tetracycline all exceeded 95%, over 60–1200 mgL^-1 chemical oxygen demand, 30–150 mgL^-1 NH₄⁺-N, and at 5–25 °C, superior to the performances reported in literature. The maximum power of the BES system peaked at 0.416 Wm⁻³ at 20 mgL^-1 TC feeding, corresponding to open circle voltage of 0.90 V and internal resistance of 799.8 Ω. The community analysis showed that the elevated TC loadings forced the predominate population to be evolved to TC-degrading consortium. The relative abundances of tetA, tetC, tetO, tetQ, and tetW in treated effluent ranged 1.20 × 10^-6 to 2.60 × 10^-4, revealing that the present BES reactor has superior removal efficiency of antibiotic resistance genes.