Application of electrochemical oxidation for the enhancement of antibiotic resistant bacteria removal in stormwater bioretention cells.

Recently, increasing attention has been paid to the removal of antibiotic resistant bacteria (ARB) during electrochemical advanced oxidation processes. However, there is still no available literature about the application of electrochemical oxidation (EO) to enhance ARB removal in stormwater bioretention cells. Batch experiments were conducted to investigate target ARB (E. coli K-12 carrying blaTEM, tetR and aphA) removals in bioretention cells with different current densities and ratios of air to water (A/W). ARB removals for bioretention cells with 17.6 μA/m of current density and 24:1 of A/W ratio was the largest with 5.28 log reduction, which was obviously higher than the one (3.68 log reduction) in the control (without EO). HO production could be responsible for ARB removals in the used bioretention cells, where HO levels increased at first and then decreased with the increase of current densities and A/W ratios. The evaluation for the application of EO implied that the highest antibiotic resistance (AR) conjugation frequency (3.8 × 10) at 3.5 μA/m of current density and 48:1 of A/W ratios was 124.5 % of the one in the control, while the largest AR transformation frequencies at 17.6 μA/m of current density and 48:1 of A/W ratios was 366.9 % (tetR) and 216.2 % (aphA) of the corresponding in the control, and there were still stable for both dominant microflora and metabolic activities in bioretention cells with electricity and aeration, suggesting that EO could be promising for the enhancement of ARB removals in bioretention cells.