Inactivation efficiency of P. Aeruginosa and ARGs removal in UV/NH2Cl process: Comparisons with UV and NH2Cl

Abstract

UV/NH2Cl process is an emerging combined disinfection method. This study comprehensively analyzed the inactivation of P. aeruginosa in UV/NH2Cl process, which is much better than that of UV alone or NH2Cl alone. The better inactivation performance was resulted from the intracellular reactive oxygen species (ROS) and reactive species produced in UV/NH2Cl process, including HO•, and reactive chlorine species (RCS). Except for the log reduction, inactivation of P. aeruginosa was displayed through the increase of membrane permeability, effluence and degradation of DNA and proteins, and destruction of cellular surface morphology. Also, the dark repair potential after UV alone and UV/NH2Cl processes were assessed and UV/NH2Cl process showed better performance. We also explored the effects of different factors on P. aeruginosa inactivation. The results showed that there was a negative correlation between P. aeruginosa inactivation and pH, and NH2Cl-UV got better inactivation effect than UV/NH2Cl. Besides, comparing the elimination of antibiotic resistance genes (ARGs) in UV, NH2Cl and UV/NH2Cl processes, it was found that UV/NH2Cl process was highly effective in simultaneous removal of P. aeruginosa and ARGs. Overall, our present study supplies much useful information for the potential application of UV/NH2Cl process.