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The depletion of blaKPC (K. pneumoniae), blaOXA-50 (P. aeruginosa) and mecA (S. aureus) genes from hospital urines is evaluated to contribute to solve the silent pandemic of antibiotic-resistance bacteria. A microfluidic flow-through reactor with MMO anode and CB/PTFE cathode working at 50 A m−2 is employed during electrodisinfection and photo-electrodisinfection processes. The electrodisinfection process only achieves an almost negligible removal of DNA and slightly log ARG increments of 0.18, 0.19 and 0.71 for blaOXA-50, mecA and blaKPC genes, respectively. Conversely, the photo-electrodisinfection process attains the complete disinfection for all ARB tested and logarithmic removals of 3.70, 2.25 and 0.82 for blaOXA-50, mecA and blaKPC genes, respectively. These outcomes emphasize the potential of the UV light coupled to the electrodisinfection process to promote the formation of not only hypochlorite but also chlorine and even nitrogen radicals, which contribute to enhance the disinfection efficiency of the target ARB and their ARGs., Se evalúa la depleción de los genes bla KPC ( K. pneumoniae ), bla OXA-50 ( P. aeruginosa ) y mec A ( S. aureus ) de orinas hospitalarias para contribuir a solucionar la pandemia silenciosa de bacterias resistentes a los antibióticos. Se emplea un reactor de flujo continuo de microfluidos con ánodo MMO y cátodo CB/PTFE que trabaja a 50 A m - 2 durante los procesos de electrodesinfección y fotoelectrodesinfección. El proceso de electrodesinfección solo logra una eliminación casi insignificante de ADN y aumentos ligeramente logarítmicos de ARG de 0,18, 0,19 y 0,71 para bla OXA-50 , mec A y bla KPCgenes, respectivamente. Por el contrario, el proceso de fotoelectrodesinfección logra la desinfección completa para todos los ARB probados y eliminaciones logarítmicas de 3,70, 2,25 y 0,82 para los genes bla OXA-50 , mec A y bla KPC , respectivamente. Estos resultados enfatizan el potencial de la luz ultravioleta junto con el proceso de electrodesinfección para promover la formación no solo de hipoclorito sino también de radicales de cloro e incluso nitrógeno, que contribuyen a mejorar la eficiencia de desinfección del ARB objetivo y sus ARG.

Textile industries generate large volumes of wastewater containing organic dyes, which may be hazardous to the environment and human health. In this work, the oxidation of 100 mg dm−3 of methylene blue (MB) in aqueous solutions was studied using H2O2 (formed in-situ) at gas diffusion electrodes (GDEs) in the presence of 1 × 10−3 mol dm−3 Fe2+ catalyst, to create hydroxyl radicals and facilitate Fenton oxidation. The influence of applied potential (−0.5 to −1.3 V vs. Ag/AgCl) at different oxygen flow rates to the GDE (0.15–0.45 cm3 min−1) and different counter electrode materials (Pt mesh, Ni mesh, RVC) was investigated. MB was completely degraded to a residual concentration below the detection limit of 0.5 mg dm−3. The rate and degree of mineralisation were significantly influenced by the applied potential. A maximum mineralisation of 88.2% was achieved at −1.0 V vs. Ag/AgCl. The oxygen flow rate to the GDE did not influence the degradation of MB under the experimental conditions. The counter electrode material affected the degree of mineralisation in the order Pt mesh > reticulated vitreous carbon (RVC) > Ni mesh. The apparent first order rate decay constant for MB degradation and MB mineralisation was calculated to have a maximum value of 0.0182 min−1 for MB mineralisation at a potential of −1.0 V vs. Ag/AgCl.

A mathematical model previously proposed by our group has been modified for its application in the modelling of arsenates, nitrates and phosphates electro-coagulation with iron and aluminium. It classifies the coagulant and pollutant species attending to their reactivity in the electro-coagulation process on the basis of the experimental behaviour of the system. The enmeshment of anionic pollutants in a growing coagulant precipitate and their direct precipitation are the mechanisms considered. A good reproducibility of the experimental data is obtained (with r2 above 0.9) with a small number of parameters. The model has been used to predict the amount of coagulant dose required under given conditions for the removal of the anionic pollutants, which allowed obtaining the costs of the electro-coagulation corresponding to the raw material, iron or aluminium sheets, and the energy costs for their electro-dissolution. Results showed that iron electro-coagulation is cheaper than aluminium electro-coagulation, and that the current density does not have an important influence on the costs within the range studied (0.2–4.0 mA cm−2). Attending to the results, arsenate and phosphate removal by electro-coagulation seem to be attractive from the economic point of view.

Summarization: In this work, the electrochemical disinfection with conductive diamond electrodes was studied to treat simulated ballast water. Artemia salina was used as indicator organism and Escherichia coli as indicator bacterium. The influence of salinity (3 and 30 g/L NaCl simulating brackish and ballast water, respectively), current density (up to 1273 A/m2) and operation mode (batch and single-pass) on inactivation and total residual chlorine production rates was investigated. An increase in salinity and current density generally had a beneficial effect on both rates. A. salina in ballast water was completely inactivated after 45 min of batch treatment at 255 A/m2 (corresponding to about 200 mg/L of produced chlorine) and this increased to 60 min in brackish water. A. salina, whose inactivation follows first order kinetics, was found to be more resistant to electrochemical disinfection than E. coli. The complete inactivation of E. coli was achieved in less than 5 min of batch operation at 127 A/m2, whereas the concentration of produced chlorine was less than 20 mg/L. Operation in single-pass mode was less effective for A. salina because it did not suffer mechanical stress, whereas E. coli inactivation occurred at low current densities and irrespective of the salinity due to both direct oxidation on the surface of conductive diamond anode and chemical reactions with chlorine species and/or reactive oxygen species. Presented on: Chemical Engineering Journal