Removal of Antibiotic Resistant Bacteria and Genes by UV-Assisted Electrochemical Oxidation on Degenerative TiO₂ Nanotube Arrays

Abstract

Antibiotic resistance has become a global crisis in recent years, while wastewater treatment plants (WWTPs) have been identified as a significant source of both antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). However, commonly used disinfectants have been shown to be ineffective for the elimination of ARGs. With the goal of upgrading the conventional UV disinfection unit with stronger capability to combat ARB and ARGs, we developed a UV-assisted electrochemical oxidation (UV-EO) process that employs blue TiO2 nanotube arrays (BNTAs) as photoanodes. Inactivation of tetracycline- and sulfamethoxazole-resistant E. coli along with degradation of the corresponding plasmid coded genes (tetA and sul1) is measured by plate counting on selective agar and qPCR, respectively. In comparison with UV254 irradiation alone, enhanced ARB inactivation and ARG degradation is achieved by UV-EO. Chloride significantly promotes the inactivation efficiency due to the electrochemical production of free chlorine and the subsequent UV/chlorine photoreactions. The fluence-based first-order kinetic rate coefficients of UV-EO in Cl– are larger than those of UV254 irradiation alone by a factor of 2.1–2.3 and 1.3–1.8 for the long and short target genes, respectively. The mechanism of plasmid DNA damage by different radical species is further explored using gel electrophoresis and computational kinetic modeling. The process can effectively eliminate ARB and ARGs in latrine wastewater, though the kinetics were retarded.

Research progress of electrochemical oxidation and self-action of electric field for medical wastewater treatment

“…Therefore, it is very necessary to add a preprocessing system to remove suspended solids. In particular, the combination of electrochemical oxidation and other methods also shows a good disinfection effect, such as sequential electrocoagulation and electrooxidation treatment system (Heffron et al, 2019), UV-assisted electrochemical oxidation (Wang et al, 2021), photoassisted electrochemical advanced oxidation process (Herraiz-Carboné et al, 2021). The mechanism diagram of electrochemical oxidation sterilization is as follows (Figure 1).…”

Elimination and Redistribution of Intracellular and Extracellular Antibiotic Resistance Genes in Water and Wastewater Disinfection Processes: A Review

“…Statistical analysis of the LRVs of iARGs and eARGs in DDI water and secondary effluent by UV treatment based on the data collected from the literature: ,,,− ,,,,,,− (a) iARGs in DDI water, (b) eARGs in DDI water, (c) iARGs in secondary effluent, and (d) eARGs in secondary effluent. The box refers to the 25th percentile, the median, and the 75th percentile, and the whiskers show the fifth and 95th percentiles.…”

Traditional and Emerging Water Disinfection Technologies Challenging the Control of Antibiotic-Resistant Bacteria and Antibiotic Resistance Genes

“…131,132 This leads to a longer lifetime of the charge and therefore improves the photocatalytic activity. 131,132 Simultaneously, the oxidation of water through the anode surface and the possible direct electron transfer reaction will inevitably increase the oxidation rate of pollutants. 133 In addition, since the catalyst is immobilized on the conductive substrate in the PEC, there is no challenge of catalyst recovery after treatment in the photocatalytic device.…”

“…PEC is an improved advanced oxidation processes based on PC; it applies a potential bias to timely remove the photogenerated electrons, suppressing the recombination of photoelectrons with photoholes. , This leads to a longer lifetime of the charge and therefore improves the photocatalytic activity. , Simultaneously, the oxidation of water through the anode surface and the possible direct electron transfer reaction will inevitably increase the oxidation rate of pollutants . In addition, since the catalyst is immobilized on the conductive substrate in the PEC, there is no challenge of catalyst recovery after treatment in the photocatalytic device .…”