The role of chloramines on the electrodisinfection of Klebsiella pneumoniae in hospital urines

Abstract

In this work, the electrochemical disinfection of synthetic hospital urines inoculated with Klebsiella pneumoniae (K. pneumoniae) as antibiotic resistant bacteria model was evaluated, paying special attention to the formation and contribution of chloramines on the disinfection performance. A novel microfluidic flow-through reactor and a conventional parallel flow reactor equipped with Mixed Metal Oxide (MMO) electrodes as anode material were also compared. The influence of the current density was assessed within the range 5–50 A m−2. Results show that the inactivation increases more than 5 log units when varying the current density from 5 to 50 A m−2, regardless the reactor layout tested. The complete disinfection (7-log reduction) is attained before 120 min (Q: 0.278 Ah dm−3) at 50 A m−2 using the flow-through reactor. Chemical disinfection tests confirm the influence on the K. pneumoniae inactivation of both, the concentration and the exposure time, using hypochlorite and chloramine disinfectants. Unless the presence of chloramines slows down the removal of bacteria in hospital urine, they may avoid the formation of undesirable chlorine by-products. This is more remarkable when working with the flow-through reactor because it induces the accumulation of 2 times higher concentration of chloramines respect to the parallel flow under the same applied electric charge values. Hence, these results point out the important role of chloramines on the electrodisinfection of hospital urines.