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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.

The composition and concentration of airborne microorganisms in hospital indoor air has been reported to contain airborne bacteria and fungi concentrations ranged 101–103 CFU/m3 in inpatients facilities which mostly exceed recommendations from the World Health Organization (WHO). In this work, a deeper knowledge of the performance of airborne microorganisms would allow improving the designs of the air-conditioning installations to restrict hospital-acquired infections (HAIs). A solution containing Escherichia coli (E. coli) as a model of airborne bacteria was nebulized using the Collison nebulizer to simulate bioaerosols in various hospital areas such as patients’ rooms or bathrooms. Results showed that the bioaerosol source had a significant influence on the airborne bacteria concentrations since 4.00 102, 6.84 103 and 1.39 104 CFU mL−1 were monitored during the aerosolization for 10 min of urine, saliva and urban wastewater, respectively. These results may be explained considering the quite narrow distribution profile of drop sizes around 1.10–1.29 μm obtained for urban wastewater, with much vaster distribution profiles during the aerosolization of urine or saliva. The airborne bacteria concentration may increase up to 107 CFU mL−1 for longer sampling times and higher aerosolization pressures, causing several cell damages. The cell membrane damage index (ID) can vary from 0 to 1, depending on the genomic DNA releases from bacteria. In fact, the ID of E. coli was more than two times higher (0.33 vs. 0.72) when increasing the pressure of air flow was applied from 1 to 2 bar. Finally, the ventilation air flow also affected the distribution of bioaerosols due to its direct relationship with the relative humidity of indoor air. Specifically, the airborne bacteria concentration diminished almost below 3-logs by applying more than 10 L min−1 during the aerosolization of urine due to their inactivation by an increase in their osmotic pressure., La composición y concentración de los microorganismos transportados por el aire en el interior de los hospitales contiene concentraciones de bacterias y hongos que oscilan entre 101 y 103 UFC/m3 en los centros de hospitalización, que en la mayoría de los casos superan las recomendaciones de la Organización Mundial de la Salud (OMS). En este trabajo, un conocimiento más profundo del comportamiento de los microorganismos transportados por el aire permitiría mejorar los diseños de las instalaciones de aire acondicionado para restringir las infecciones adquiridas en el hospital (HAI). Se nebulizó una solución que contenía Escherichia coli (E. coli) como modelo de bacteria aerotransportada utilizando el nebulizador Collison para simular bioaerosoles en diversas áreas hospitalarias, como las habitaciones o los baños de los pacientes. Los resultados mostraron que la fuente del bioaerosol tenía una influencia significativa en las concentraciones de bacterias aerotransportadas, ya que se monitorizaron 4,00 102, 6,84 103 y 1,39 104 UFC mL-1 durante la aerosolización durante 10 minutos de orina, saliva y aguas residuales urbanas, respectivamente. Estos resultados pueden explicarse considerando el perfil de distribución bastante estrecho de tamaños de gota alrededor de 1,10-1,29 μm obtenido para las aguas residuales urbanas, con perfiles de distribución mucho más amplios durante la aerosolización de orina o saliva. La concentración de bacterias en el aire puede aumentar hasta 107 UFC mL-1 para tiempos de muestreo más largos y presiones de aerosolización más altas, causando varios daños celulares. El índice de daño de la membrana celular (ID) puede variar de 0 a 1, dependiendo de la liberación de ADN genómico de las bacterias. De hecho, el ID de E. coli fue más de dos veces superior (0,33 frente a 0,72) al aumentar la presión del flujo de aire de 1 a 2 bares. Por último, el flujo de aire de ventilación también afectó a la distribución de los bioaerosoles debido a su relación directa con la humedad relativa del aire interior. Concretamente, la concentración de bacterias en el aire disminuyó casi por debajo de 3 logs al aplicar más de 10 L min-1 durante la aerosolización de la orina debido a su inactivación por un aumento de su presión osmótica.

In this work, data obtained from the University Hospital Complex of Albacete (Spain) were selected as a case study to carry out the disinfection experiments. To do this, different configurations of electrochemical reactors were tested for the disinfection of complex urines. Results showed that 4–6 logs bacterial removal were achieved for every bacterium tested when working with a microfluidic flow-through reactor after 180 min (0.423 Ah dm−3). The MIKROZON® cell reached a total disinfection after 60 min (1.212 Ah dm−3), causing severe damages induced in the cell walls observed in SEM images. The concentration profiles of the electrogenerated disinfectants in solution could explain the differences observed. Additionally, a mean decrease in the ARGs concentration ranked as follows: blaKPC (4.18-logs) > blaTEM (3.96-logs) > ermB (3.23-logs) using the MIKROZON® cell. This electro-ozonizer could be considered as a suitable alternative to reduce the risk of antibiotic resistance spread. Hence, this study provides an insight into different electrochemical reactors for the disinfection of complex hospital urine matrices and contributes to reduce the spread of antibiotic resistance through the elimination of ARGs. A topic of great importance nowadays that needs to be further studied., En este trabajo se seleccionaron datos obtenidos del Complejo Hospitalario Universitario de Albacete (España) como caso de estudio para llevar a cabo los experimentos de desinfección. Para ello, se probaron diferentes configuraciones de reactores electroquímicos para la desinfección de orinas complejas. Los resultados mostraron que se lograron entre 4 y 6 logaritmos de eliminación de bacterias por cada bacteria analizada cuando se trabajaba con un reactor de flujo continuo de microfluidos después de 180 min (0,423 Ah dm −3 ). La celda MIKROZON® alcanzó una desinfección total a los 60 min (1.212 Ah dm −3 ), provocando severos daños inducidos en las paredes celulares observados en SEMimágenes Los perfiles de concentración de los desinfectantes electrogenerados en solución podrían explicar las diferencias observadas. Además, una disminución media en la concentración de ARG se clasificó de la siguiente manera: bla KPC (4,18 logs) > bla TEM (3,96 logs) > erm B (3,23 logs) usando la celda MIKROZON®. Este electro-ozonizador podría considerarse como una alternativa adecuada para reducir el riesgo de propagación de la resistencia a los antibióticos. Por lo tanto, este estudio proporciona una idea de los diferentes reactores electroquímicos para la desinfección de matrices de orina hospitalarias complejas y contribuye a reducir la propagación de la resistencia a los antibióticos mediante la eliminación de los ARG. Un tema de gran importancia en la actualidad que necesita ser más estudiado.

In the University Hospital of Albacete (Spain), the distribution of Active Pharmaceutical Ingredients (APIs) was studied to estimate the occurrence of the most prevalent analgesics and anti-inflammatories and antibiotics in patients’ urines. This estimation was based on the consumption amounts of APIs and their pharmacokinetic data. Results showed that metamizole would be the most prevalent drug among analgesics and anti-inflammatories with estimated concentrations ranging 100 – 1000 mg dm−3 in patients’ urines hospitalized in the surgical ICU, followed by around 10 mg dm−3 of acetylcysteine in surgical ICU and paracetamol in geriatrics. Likewise, estimated concentrations of 1–10 mg dm−3 were calculated for the 20 most representative antibiotics. Two β-lactam antibiotics (imipenem, meropenem) and one fluoroquinolone antibiotic (levofloxacin) would be present in patients’ urine from more than 3 surgical and medical areas. Additionally, the simulation of the toxicity impacts of active pharmaceutical ingredients (APIs) in hospital effluents was developed using the SimaPro 9.3.0.3 software and Ecoinvent 3.3 database since few studies were reported based on the real occurrence of drugs in urines. Ibuprofen was observed to have 2.4 times more ecotoxicity in freshwaters than paracetamol, although they did not show human toxicity related to carcinogenic effects. Amoxicillin presented a high potential ecological risk with a 3 kg equivalence of 1.4-DB per gram of drug. Overall, results demonstrate the importance to develop an adequate management and treatment of hospital effluents, including hospital urines, to reduce environmental and sanitary impacts., En el Hospital Universitario de Albacete (España) se estudió la distribución de Principios Activos Farmacéuticos (IFA) para estimar la presencia de los analgésicos y antiinflamatorios y antibióticos más prevalentes en la orina de los pacientes. Esta estimación se basó en las cantidades de consumo de API y sus datos farmacocinéticos . Los resultados mostraron que el metamizol sería el fármaco más prevalente entre los analgésicos y antiinflamatorios con concentraciones estimadas que oscilan entre 100 y 1000 mg dm- 3 en la orina de los pacientes hospitalizados en la UCI quirúrgica, seguido de alrededor de 10 mg dm - 3 de acetilcisteína en la UCI quirúrgica. y paracetamol en geriatría . Asimismo, concentraciones estimadas de 1–10 mg dm −3se calcularon para los 20 antibióticos más representativos. Dos antibióticos β-lactámicos (imipenem, meropenem) y un antibiótico de fluoroquinolona (levofloxacino) estarían presentes en la orina de pacientes de más de 3 áreas quirúrgicas y médicas. Adicionalmente, se desarrolló la simulación de los impactos de toxicidad de los principios activos farmacéuticos (API) en efluentes hospitalarios utilizando el software SimaPro 9.3.0.3 y la base de datos Ecoinvent 3.3 ya que se reportaron pocos estudios basados ​​en la ocurrencia real de fármacos en orina. Ibuprofenose observó que tenía 2,4 veces más ecotoxicidad en agua dulce que el paracetamol, aunque no mostró toxicidad humana relacionada con efectos cancerígenos. La amoxicilina presentó un alto riesgo ecológico potencial con una equivalencia de 3 kg de 1,4 DB por gramo de fármaco. En general, los resultados demuestran la importancia de desarrollar un manejo y tratamiento adecuado de los efluentes hospitalarios, incluidas las orinas hospitalarias, para reducir los impactos ambientales y sanitarios.

This work evaluates the integration of dehalogenation with Zero Valent Iron (ZVI) and electrochemical oxidation (EO) for the treatment of urines polluted with iodinated X-ray contrast media (ICM). To do this, different strategies were evaluated: pretreatment with ZVI followed by EO (ZVI-EO) or electrolysis enhanced with ZVI-dehalogenation (EO/ZVI). For comparison purposes, single electrolysis was also performed to check the best treatment strategy. Results showed that EO was less efficient than EO/ZVI and ZVI-EO processes. Removal percentages of 74.9%, 87.6% and 99.5% were reached after passing 13.8 Ah dm−3 at 10 mA cm−2 during EO, EO/ZVI and ZVI-EO, respectively. EO/ZVI process favored the production of large amounts of hydroxyl radicals in the effluent through Fenton´s reaction, enhancing the degradation rate of iopamidol (IPM). The pretreatment with ZVI allowed to transform up to 95% of IPM to C17H25N3O8. Then, electrolysis attained the almost complete removal of the raw pollutant (ZVI-EO). The different iodine species formed at the end of the treatment were also monitored, finding similar proportions of organic iodine species for EO and EO/ZVI processes, although single EO promoted the formation of the stable inorganic iodine (IO3-) and EO/ZVI favored the release of I-. Total organic carbon removal percentages lower than 20% were achieved, suggesting that the technologies employed were selective for the removal of the target pollutant under the operating conditions studied. Finally, the organic IPM by-products were also identified by LC-MS and the chromatographic area profiles showed higher values for EO/ZVI followed by ZVI-EO and EO., Este trabajo evalúa la integración de la deshalogenación con Hierro Cero Valente (ZVI) y la oxidación electroquímica (EO) para el tratamiento de orinas contaminadas con medios de contraste de rayos X (ICM) yodados. Para ello se evaluaron diferentes estrategias: pretratamiento con ZVI seguido de EO (ZVI-EO) o electrólisis potenciada con ZVI-deshalogenación (EO/ZVI). Con fines comparativos, también se realizó electrólisis simple para comprobar la mejor estrategia de tratamiento. Los resultados mostraron que EO fue menos eficiente que los procesos EO/ZVI y ZVI-EO. Se alcanzaron porcentajes de eliminación del 74,9%, 87,6% y 99,5% tras pasar 13,8 Ah dm- 3 a 10 mA cm- 2durante EO, EO/ZVI y ZVI-EO, respectivamente. El proceso EO/ZVI favoreció la producción de grandes cantidades de radicales hidroxilo en el efluente a través de la reacción de Fenton, mejorando la tasa de degradación del iopamidol (IPM). El pretratamiento con ZVI permitió transformar hasta el 95% de IPM a C 17 H 25 N 3 O 8 . Luego, la electrólisis logró la remoción casi completa del contaminante crudo (ZVI-EO). También se monitorearon las diferentes especies de yodo formadas al final del tratamiento, encontrando proporciones similares de especies de yodo orgánico para los procesos EO y EO/ZVI, aunque solo EO promovió la formación del yodo inorgánico estable (IO 3 - ) y EO/ZVI favoreció la liberación de I -. Se lograron porcentajes de remoción de carbono orgánico total inferiores al 20%, lo que sugiere que las tecnologías empleadas fueron selectivas para la remoción del contaminante objetivo en las condiciones de operación estudiadas. Finalmente, los subproductos orgánicos de IPM también fueron identificados por LC-MS y los perfiles de área cromatográfica mostraron valores más altos para EO/ZVI seguido por ZVI-EO y EO.

This work focuses on the application of electrolysis with diamond anodes for the disinfection of urine. To do this, a synthetic human urine was polluted with Escherichia coli and Pseudomonas aeruginosa and then, it was electrolyzed at current densities within the range 0–100 A m−2. Results show that it is possible to disinfect completely the effluent even at applied electric charges lower than 2 kAh m−3, regardless the current density applied. This good performance is related to the production of powerful oxidants from the oxidation of the ions present in synthetic urine. Likewise, these species also react with the organics contained in urine (urea, creatinine and uric acid), favoring their degradation. The process efficiency for both microorganisms and organics is higher when working at low current densities. The removal of organics leads to the release of significant amounts of nitrogen in the form of nitrate which are later electroreduced to ammonium, that, in turn, reacts with the electrogenerated hypochlorite, favoring the production of chloramines (which can also contribute to the disinfection process). Regarding the mineralization, TOC removal higher than 90% can be achieved but higher applied electric charges than those required for disinfection have to be applied (around 30 kAh m−3).

Antibiotic-resistant bacteria (ARB) is one of the biggest public health challenges of our time since causes thousands of human deaths per year. ARB are bacteria which acquire resistance over time through different mechanism and no longer respond to antibiotics. Numerous bacteria and hydrophilic antibiotics are mainly excreted in patients' urine from sanitary facilities that are directly discharge into municipal sewers. The inefficiency of conventional wastewater treatment plants (WWTPs) for killing ARB leads to their spread in the natural water sources. In this work, a statistical study of the main microorganisms contained in patients’ urines with urinary tract infections (UTIs) was analysed using the data supplied from the microbiology and parasitology service in the university hospital complex of Albacete (Spain). A total of 14,368 urine samples were analysed on five hospital units (geriatrics, haematology, oncology, reanimation, and intensive care unit (ICU)) from 2014 to 2018. A chi-square (X2) study demonstrated the female prevalence to suffer UTIs in geriatrics, oncology and reanimation units. In addition, the analysis of ARB producing extended spectrum beta-lactamases (ARBESBLs), carbapenemase-producing bacteria (ARBCPB) and methicillin-resistant Staphyloccocus aureus (ARBMRSA) were also evaluated. Finally, the literature related to the disinfection of the main ARB previously found in hospital urine was analysed to evaluate the importance given to ARB from an environmental scientific viewpoint., Las bacterias resistentes a los antibióticos (ARB) son uno de los mayores desafíos de salud pública de nuestro tiempo, ya que causan miles de muertes humanas por año. Los ARB son bacterias que adquieren resistencia con el tiempo a través de diferentes mecanismos y ya no responden a los antibióticos. Numerosas bacterias y antibióticos hidrofílicos se excretan principalmente en la orina de los pacientes de las instalaciones sanitarias que se vierten directamente en las alcantarillas municipales. La ineficiencia de las plantas de tratamiento de aguas residuales (WWTP) convencionales para matar ARB conduce a su propagación en las fuentes de agua naturales. En este trabajo se analizó un estudio estadístico de los principales microorganismos contenidos en la orina de pacientes con infecciones del tracto urinario (ITU) utilizando los datos proporcionados por la microbiologíay servicio de parasitologíaen el complejo hospitalario universitario de Albacete (España). Se analizaron un total de 14.368 muestras de orina en cinco unidades hospitalarias (geriatría, hematología , oncología , reanimación y unidad de cuidados intensivos (UCI)) de 2014 a 2018. Un estudio de chi-cuadrado ( X2) demostró la prevalencia femenina de padecer ITU engeriatría, oncología y reanimación. Además, el análisis de ARB productoras de betalactamasas de espectro extendido (ARBESBL), bacterias productoras de carbapenemasas (ARBCPB) yStaphyloccocus aureus(ARBMRSA) también fueron evaluados. Finalmente, se analizó la literatura relacionada con la desinfección de los principales BRA encontrados previamente en la orina hospitalaria para evaluar la importancia que se le da a los BRA desde un punto de vista científico ambiental.

This work evaluates the performance of a pressurized heterogeneous electro-Fenton (EF) process to transform the antibiotic into compounds that do not promote the appearance of bacteria resistant to antibiotic in the environment. Experimental system consisted of a pressurized non divided microfluidic electrochemical cell equipped with a jet aerator, flow-through electrodes and a fluidized bed of goethite as heterogeneous iron catalyst. Results show that meropenem (model antibiotic) can be degraded by EF and that the degradation rate depends on the gauge pressure applied: the higher is the pressurization, the faster is the abatement of meropenem. The antibiotic effect of the urine is related to meropenem remained in the treated urine, and the contribution of reaction intermediates does not seem to be relevant. The mineralization of the organic load is almost nil. The higher dissolved oxygen concentration of pressurized-EF and thus, the higher hydrogen peroxide generation seems to be the key point to explain the effect of pressure on EF process. Results confirm that moderated pressurized EF process (up to 3 bar) can be satisfactorily used to decrease the chemical risk of synthetic hospital urines, which opens the possibility of an optimized pre-treatment which may help to save cost in the treatment of these hazardous wastes. This work evaluates the performance of a pressurized heterogeneous electro-Fenton (EF) process to transform the antibiotic into compounds that do not promote the appearance of bacteria resistant to antibiotic in the environment. Experimental system consisted of a pressurized non divided microfluidic electrochemical cell equipped with a jet aerator, flow-through electrodes and a fluidized bed of goethite as heterogeneous iron catalyst. Results show that meropenem (model antibiotic) can be degraded by EF and that the degradation rate depends on the gauge pressure applied: the higher is the pressurization, the faster is the abatement of meropenem. The antibiotic effect of the urine is related to meropenem remained in the treated urine, and the contribution of reaction intermediates does not seem to be relevant. The mineralization of the organic load is almost nil. The higher dissolved oxygen concentration of pressurized-EF and thus, the higher hydrogen peroxide generation seems to be the key point to explain the effect of pressure on EF process. Results confirm that moderated pressurized EF process (up to 3 bar) can be satisfactorily used to decrease the chemical risk of synthetic hospital urines, which opens the possibility of an optimized pre-treatment which may help to save cost in the treatment of these hazardous wastes.

The occurrence of antibiotic-resistant bacteria (ARB) in water bodies poses a sanitary and environmental risk. These ARB and other mobile genetic elements can be easily spread from hospital facilities, the point in which, for sure, they are more concentrated. For this reason, novel clean and efficient technologies are being developed for allowing to remove these ARB and other mobile genetic elements before their uncontrolled spread. In this paper, a review on the recent knowledge about the state of the art of the main disinfection technologies to control the antibiotic resistance spread from natural water, wastewater, and hospital wastewater (including urine matrices) is reported. These technologies involve not only conventional processes, but also the recent advances on advanced oxidation processes (AOPs), including electrochemical advanced oxidation processes (EAOPs). This review summarizes the state of the art on the applicability of these technologies and also focuses on the description of the disinfection mechanisms by each technology, highlighting the promising impact of EAOPs on the remediation of this important environmental and health problem., La aparición de bacterias resistentes a los antibióticos (BRA) en los cuerpos de agua supone un riesgo sanitario y ambiental. Estos BRA y otros elementos genéticos móviles pueden propagarse fácilmente desde las instalaciones hospitalarias, punto en el que, a buen seguro, se concentran más. Por ello, se están desarrollando novedosas tecnologías limpias y eficientes que permitan eliminar estos BRA y otros elementos genéticos móviles antes de su propagación descontrolada. En este artículo se presenta una revisión del conocimiento reciente sobre el estado del arte de las principales tecnologías de desinfección para controlar la propagación de la resistencia a los antibióticos en aguas naturales, aguas residuales y aguas residuales hospitalarias (incluidas las matrices de orina). Estas tecnologías involucran no solo procesos convencionales, sino también los avances recientes en procesos de oxidación avanzada .(AOP), incluidos los procesos electroquímicos de oxidación avanzada (EAOP). Esta revisión resume el estado del arte sobre la aplicabilidad de estas tecnologías y también se enfoca en la descripción de los mecanismos de desinfección por cada tecnología, destacando el impacto prometedor de los EAOP en la remediación de este importante problema ambiental y de salud.

This work presents a novel photoelectrochemical cell concept for the treatment of soil washing effluents polluted with chlorinated hydrocarbons (CHCs). This cell combines the use of low current densities and the direct irradiation of UV light to the electrodes and the bulk, being easy to be scaled up. To evaluate its performance, the treatment of a soil washing effluent polluted with clofibric acid (~50 mg dm−3) was carried out. The prototype evaluated was equipped with two boron doped diamond (BDD) plates as anodes, two stainless steel (SS) plates as cathodes and a UV lamp located at the bottom. Results show that it was possible to attain a complete abatement and mineralization of the organochlorinated compound at applied electric charges lower than 5 Ah dm−3, regardless the irradiation of UV light. Nevertheless, the removal rate was higher during photoelectrolysis, specially at the beginning of the treatment, which indicates important advantages for the removal of aromatic compounds. In addition, the toxicity of the effluent was dramatically reduced at the end of the process. These results point out the high performance of the novel photoelectrochemical reactor proposed for the complete remediation of soils polluted with CHCs.

In the present work, the influence of the water matrix on the removal of antibiotic resistant bacteria during the electro-disinfection with diamond anodes was studied, paying special attention to the disinfection efficiency and the prevention of the formation of hazardous disinfection by-products. This will allow to evaluate if electrolysis is more suitable as pretreatment of the main pollution source or as tertiary treatment of urban wastewater. To do this, electrolysis of synthetic wastewater rich in ammonium (simulating the effluent of an oxidation pond) and hospital urine intensified with three different bacteria (E. faecalis, K. pneumoniae, and E. coli) were carried out. Results show that the disinfection efficiency is higher in the synthetic wastewater for all the bacteria tested, but chlorate is formed as disinfection by-product. Electrogenerated hypochlorite and chloramines are the main responsible species for bacteria depletion. Presence of organics (urea, creatinine and uric acid) as additional ammonia precursors in hospital urine leads to the well-known breakpoint reaction with electrogenerated active chlorine, yielding an increasing concentration of chloramines. This helps to prevent the formation of chlorate in hospital urine because hypochlorite is mainly wasted in the oxidation of organics and the formation of chloramines. These results are of a great significance because they indicate that antibiotic resistant bacteria can be efficiently removed in complex matrixes without the formation of hazardous chlorine by-products if it is carried out as a pretreatment before discharge to WWTP.

In this work, coagulation and electrocoagulation for the removal of cyanide ions contained in synthetic mining wastewater were evaluated paying particular attention to the elucidation of the coagulation mechanisms. Iron and aluminum salts with concentrations ranging from 0.01 to 10 000 mg dm−3 metal were used in chemical coagulation. Experimental data were properly fitted to Freundlich isotherm to elucidate that the main mechanism to remove cyanide during chemical coagulation was adsorption onto coagulant flocs although a maximum cyanide removal percentage of only 25% was attained. Then, electrochemical coagulation with iron and aluminum electrodes was evaluated at 1, 10 and 100 A m−2, obtaining completely different results. Iron electrochemical coagulation leads to the complete cyanide removal regardless of the current density applied, although the TOC removal was much lower than expected. On the contrary, only 60% of cyanide removal was reached by aluminum electrochemical coagulation and its efficiency was found to be highly dependent on the current density applied. Furthermore, no cyanate or hazardous inorganic chlorine species were detected during both electrocoagulation processes. However, chloride was oxidized to hypochlorite and then, it reacted with ammonium ions (contained in mining wastewater or produced by chemical reduction of nitrate by aluminum) to form chloramines. A proposal of coagulation mechanisms during the electrochemical process that explains experimental results was developed which involved the formation of iron-cyanide complexes, charge neutralization, adsorption on a superficially charged metal precipitate and/or enmeshment into a sweep metal floc.

The electrolysis with diamond anodes of synthetic urines containing different concentrations of ibuprofen and cloxacillin is evaluated in this work, with the aim of determining if this technology is effective in the mineralization of both species in urine matrix and the main characteristics of the competitive oxidation among these two products and the natural organic compounds contained in urine (uric acid, creatinine and urea). Results point out that electrolytic technology can mineralize all organic contained in the urine very efficiently and that oxidation of the two pharmaceuticals is faster than that of the natural products contained in urine, opening the possibility of a selective treatment of the urine up to the point in which it can be merged safely with domestic wastewater without generating a negative impact on environment. Occurrence of perchlorate is the main drawback of this technology, although its impact is not believed to be as serious as the impact of the pharmaceuticals on environment.

In this work, the disinfection of urines polluted with Klebsiella pneumoniae (K. pneumoniae) using a commercial electro-ozonizer is described. The device consists of a membrane-electrode assembly flow cell that specially promotes the electrochemical generation of ozone. Results show that a complete disinfection is attained in less than 180 min when working at current intensities higher than 0.5 A. The higher the current intensity, the higher the disinfection rate. Furthermore, the use of an electro-ozonizer for treating diluted urines leads to higher disinfection efficiencies. Ozone and chlorine-based disinfectants (hypochlorite and chloramines) were identified as the main oxidant species involved in killing bacteria. The combined effect of all disinfectants promotes higher removal efficiencies in comparison with the single effect of ozone evaluated in a urine matrix without chlorides, being more remarkable at lower current intensities. The crystal violet assay showed that cell wall is damaged by the electrogenerated oxidants and it is more remarkable by the combined effect of ozone and chlorine disinfectants when increasing the current intensity. Finally, the degradation of total proteins and genetic material (DNA) were also monitored and related to the oxidants produced during the electrochemical process.

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., o En este trabajo se evaluó la desinfección electroquímica de orina sintética hospitalaria inoculada con Klebsiella pneumoniae ( K. pneumoniae ) como modelo de bacteria resistente a antibióticos, prestando especial atención a la formación y contribución de cloraminas en el desempeño de la desinfección. También se compararon un reactor de flujo continuo de microfluidos novedoso y un reactor de flujo paralelo convencional equipado con electrodos de óxido metálico mixto (MMO) como material anódico. La influencia de la densidad de corriente se evaluó dentro del rango de 5 a 50 A m −2 . Los resultados muestran que la inactivación aumenta más de 5 unidades logarítmicas cuando se varía la densidad de corriente de 5 a 50 A m −2, independientemente del diseño del reactor probado. La desinfección completa (reducción de 7 log) se logra antes de 120 min (Q: 0,278 Ah dm −3 ) a 50 A m −2 utilizando el reactor de flujo continuo. Las pruebas de desinfección química confirman la influencia sobre K. pneumoniaeinactivación tanto de la concentración como del tiempo de exposición, utilizando desinfectantes de hipoclorito y cloramina. A menos que la presencia de cloraminas ralentice la eliminación de bacterias en la orina del hospital, pueden evitar la formación de subproductos de cloro indeseables. Esto es más notable cuando se trabaja con el reactor de flujo continuo porque induce la acumulación de una concentración 2 veces mayor de cloraminas con respecto al flujo paralelo bajo los mismos valores de carga eléctrica aplicados. Por lo tanto, estos resultados señalan el importante papel de las cloraminas en la electrodisinfección de la orina hospitalaria.

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.

In recent years, thousands of scientific articles have considered the application of electrochemical technologies to remediate environmental problems ranging from the treatment of polluted soils to the removal of hazardous species from industrial liquid wastes. New research topics continue to emerge. Despite such research efforts, the technology readiness level (TRL) for many of those technologies remains very low; although most are considered promising, many are far from being introduced as efficient processes into the market. Important barriers need to be overcome to reach high TRLs. Some of these are scientific or technological and generate the opportunity for critical, applied research. Others are related to the lack of components in the value chain of the technology and generate opportunities for entrepreneurs to benefit from an improvement in the TRL. In this short review, a brief description of the current state of the most relevant technologies which are still in low TRL is carried out, highlighting barriers that must be removed to achieve full-scale applications in industry.

Hospital effluents are a major source for the occurrence of pharmaceuticals in the environment. In this work, the treatment of synthetic urine polluted with chloramphenicol is studied by using three different conductive-diamond electrochemical oxidation technologies: electrolysis (single electrolysis), photoelectrolysis and high-frequency ultrasound sonoelectrolysis. These technologies were evaluated at 10 and 100 mA cm−2. Results shows that not only chloramphenicol but also other organics contained in urine are completely mineralized by electrolysis. Ammonium is the main inorganic nitrogen species formed and it can react with the electrogenerated hypochlorite, favouring the formation of chloramines. These species prevent the potential formation of perchlorate from chlorides contained in urine at low current densities (10 mA cm−2) and delay its occurrence at high current densities (100 mA cm−2). On the other hand, irradiation of ultraviolet (UV) light or high-frequency ultrasound (US) produce changes in the performance of the electrolytic treatment, but these changes are not as important as in other cases of study shown in the literature. Nonetheless, the effect of electroirradiated technologies seems to be higher and depends on the type of pollutant when working at low current densities (10 mA cm−2). It is positive in the case of the degradation of the antibiotic and the uric acid and negative in the case of urea where there is a clear antagonistic effect. Production of oxidants increases with the current density although in lower ratio than expected. These results are of great importance because clearly point out that electrolytic technologies can be applied to minimize the diffuse pollution associated to pharmaceuticals before discharge into municipal sewers.

This work focuses on the removal of sulfate from mining waters by using electrocoagulation with iron electrodes. A comparison of the results obtained by electrocoagulation with those obtained with the application of conventional chemical coagulation is provided. The results show that sulfate can be removed from synthetic mining waters by electrocoagulation, and that the pH and coagulant dosage play a very important role. During chemical coagulation under acidic conditions, it is possible to use a low dosage of iron and remove more than 80% of the sulfate present in water. However, chemical coagulation seems to behave as a kind of ion-exchange process (from the viewpoint of effluent quality). Thus, significant concentrations of accumulated chloride (counter ion of iron in the coagulant added) prevents the use of the technology. This problem is avoided by the application of electrocoagulation, which attains good efficiencies that can be even increased by using a continuous process with a flocculation tank. This technology also helps to remove other ionic pollutants contained in the wastewater.

A mathematical model is proposed to describe a diesel-polluted clayey soil bioremediation process. The reaction system under study was considered a completely mixed closed batch reactor, which initially contacted a soil matrix polluted with diesel hydrocarbons, an aqueous liquid-specific culture medium and a microbial inoculation. The model coupled the mass transfer phenomena and the distribution of hydrocarbons among four phases (solid, S; water, A; non-aqueous liquid, NAPL; and air, V) with Monod kinetics. In the first step, the model simulating abiotic conditions was used to estimate only the mass transfer coefficients. In the second step, the model including both mass transfer and biodegradation phenomena was used to estimate the biological kinetic and stoichiometric parameters. In both situations, the model predictions were validated with experimental data that corresponded to previous research by the same authors. A correct fit between the model predictions and the experimental data was observed because the modelling curves captured the major trends for the diesel distribution in each phase. The model parameters were compared to different previously reported values found in the literature. Pearson correlation coefficients were used to show the reproducibility level of the model., Se propone un modelo matemático para describir un proceso de biorremediación de suelos arcillosos contaminados con diesel. El sistema de reacción en estudio se consideró un reactor discontinuo cerrado completamente mixto, que inicialmente entró en contacto con una matriz de suelo contaminada con hidrocarburos diesel, un medio de cultivo específico líquido acuoso y una inoculación microbiana. El modelo acopló los fenómenos de transferencia de masa y la distribución de hidrocarburos entre cuatro fases (sólido, S; agua, A; líquido no acuoso, NAPL; y aire, V) con la cinética de Monod. En el primer paso, se utilizó el modelo que simula las condiciones abióticas para estimar solo los coeficientes de transferencia de masa. En el segundo paso, se utilizó el modelo que incluía tanto la transferencia de masa como los fenómenos de biodegradación para estimar los parámetros biológicos cinéticos y estequiométricos. En ambas situaciones, las predicciones del modelo fueron validadas con datos experimentales que correspondían a investigaciones previas de los mismos autores. Se observó un ajuste correcto entre las predicciones del modelo y los datos experimentales porque las curvas de modelado capturaron las principales tendencias para la distribución del diesel en cada fase. Los parámetros del modelo se compararon con diferentes valores reportados previamente encontrados en la literatura. Se utilizaron coeficientes de correlación de Pearson para mostrar el nivel de reproducibilidad del modelo.

In this work, the electrochemical production with low current densities of iron and aluminium reagents for electro-coagulation processes has been studied. It has been found that pH is a very important parameter, being strongly related to the speciation of iron in terms of iron (II) or iron (III) species, and also to the efficiency of the electrochemical reagent-dosing process. Iron (II) species are only significant under acidic conditions because in neutral and alkaline conditions iron (II) is rapidly transformed into iron (III). Efficiencies in the dissolution of the metals are very high and, in some cases, over the value expected for a 100% – efficiency (super-faradaic efficiencies), due to the non-electrolytic dissolution of the electrodes, which is very important for iron under acidic conditions, and even more important for aluminium at alkaline pHs. This significant non-electrolytic contribution explains the different trends observed in the efficiency changes with current density.

In this work, the effect of the cathode material (conductive diamond, stainless steel, silicon carbide, graphite or lead) and the current density (150–1400 A m−2) on the removal of nitrates from aqueous solutions is studied by electrolysis in non-divided electrochemical cells equipped with conductive diamond anodes, using sodium sulphate as the electrolyte. The results show that the cathode material very strongly influences both the process performance and the product distribution. The main products obtained are gaseous nitrogen (NO, N2O and NO2) and ammonium ions. Nitrate removal follows first order kinetics, which indicates that the electrolysis process is controlled by mass transfer. Furthermore, the stainless steel and graphite cathodes show a great selectivity towards the production of ammonium ions, whereas the silicon carbide cathode leads to the highest formation of gaseous nitrogen, which production is promoted at low current densities.

In this work, the electrochemical denitrification of solutions containing chlorides is studied with two different types of anode materials: O 2 -dimensionally stable anodes (DSA) and boron doped diamond (BDD). First of all, a higher rate of nitrate removal was found when chloride is used as the supporting media, with respect to sulphate. Moreover, it was found that it is necessary a minimum chloride concentration to get an effective treatment and that gaseous-nitrogen is the primary nitrogen species found in the electrolyses. In this process, nitrate is firstly reduced on the cathode surface and next oxidized by the species generated by the anode material. Thus, anode material does not influence on the denitrificacion rate, but it significantly influences on the speciation of chlorine. Furthermore, formation of perchlorates advice against the use of BDD electrochemical denitrification for the production of drinking water. Finally, formation of chlorates in the DSA-electrolyses, due to the ageing of hypochlorite, also limits its use in the production of drinking water, although it does not exclude its use in other applications such as reuse of treated wastewater and treatment of industrial wastes.

In this work, arsenic oxidation by an electrochemical process was studied in a batch bench-scale electrolysis plant equipped with mono- and bi-compartment cells, dimensionally-stable anodes (DSAs) and conductive-diamond anodes (CDAs). The results demonstrate that the electrolysis is an adequate technology to transform As(III) into As(V) species, which is an important pre-treatment stage for removing of arsenic from water using technologies such as coagulation or electro-coagulation. The process requires large current densities in non-divided cells to obtain a good As(V)/As(III) ratio, but it can be more efficiently performed at low current densities in cells divided by cationic membranes. The presence of chlorides or sulphates can significantly affect the results due to the formation of powerful oxidants that contribute to the net oxidation process.

In the present work, the removal of phosphates from waters is studied through electrocoagulation using iron and aluminium electrodes. This technology is an alternative to the conventional method of coagulation, which leads to the complete removal of phosphates below the detectable limits of ionic chromatography (0.1 mg dm −3 ). The effect of the current density using both electrodes is also studied. The results show that the pH increases with the current density. In addition, a mechanistic model is proposed for phosphate removal that considers the solubility of iron, aluminium and phosphate species, and the zeta potential values. In the case of aluminium electrodes, the coexistence of both direct precipitation and adsorption onto metal is observed, whereas in the case of iron electrodes, the adsorption mechanism is less effective.

In this work, the influence of the anodic material on the electrolysis of wastewaters polluted with nitrates is studied in non-divided electrochemical cells. Conductive-diamond (CDE) and oxygen dimensionally stable anodes (DSA-O2) were chosen as models of anodes to study this influence. Ammonium ions, nitrite and nitric oxide were found as the main species involved in the electrolysis of nitrates in sulphate media with both anodes, but CDE was found to lead to a highly more-efficient electrochemical removal of nitrate than DSA-O2. The huge differences observed for both anodes indicate an important role of electro-generated species in the overall reactivity of the system. In this work, the influence of these species is described, and the observed effect is explained in terms of the chemical and electrochemical reactivity of nitrogen species.

In this study, coagulation and electrocoagulation processes were compared with regard to their respective efficiencies as to the removal of nitrates from water. The results indicate that electrocoagulation is an effective technology for nitrate removal because nitrate anions preferentially adsorb onto the surfaces of growing metal-hydroxide precipitates. Other similar results were observed when using iron or aluminium electrodes whenever coagulation reagents, aluminium or iron, were plotted in molar units and the same adsorption isotherm was obtained. Since electrocoagulation merely acts as a dosing coagulant technology, current density does not influence the removal of nitrates from water. However, it strongly affects the feasibility of nitrate removal because current density increases the operational cell potential. In other words, current density influences the power consumption that is required to provide a specific dose of reagent. On the other hand, the coagulation results indicate that this technology is not suitable for removing nitrate from water. The huge increase in conductivity observed during coagulant dosing (in comparison to the conductivity that was obtained when using electrocoagulation) appears to promote competition among nitrates and coagulant counter ions. It also decreases the widths of the double layers that form around the precipitate particles. Both of these processes most likely explain why nitrates cannot be removed from water using a coagulation process.

In this work, removal of arsenic by electrocoagulation with iron and aluminium electrodes is studied in a batch bench scale plant. Results demonstrate that both iron and aluminium electrocoagulations are a robust technology capable of removing arsenic down to 10 μg dm−3 (the level fixed by most environmental and health agencies). Nevertheless, aluminium electrocoagulation is not as efficient as iron, one for the removal of arsenic when current densities below 2 mA cm−2 are applied. The effect of the current density (from 0.1 to 4.0 mA cm−2) is studied with both electrodes. Results show that this parameter influences slightly on the range of pH in which the process works (7–9) and also on the efficiency (always over 99.9%), but it is not a limiting parameter. Results can be easily explained taking into account the solubility of iron, aluminium and arsenates species present in the treated water.

Microcapsules with a high amount of PRS paraffin wax encapsulated and narrow size distribution were prepared by a Shirasu porous glass (SPG) emulsification technique and a subsequent suspensionlike polymerization process. An experimental design approach, based on a central composite design, was used to determine quantitatively the effect of RepSol-YPF Paraffin (PRS) paraffin wax/styrene mass ratio (PRS/St), percentage of polyvinylpyrrolidone/styrene mass ratio (% PVP/St), and water/styrene mass ratio (H2O/St) on the phase change material (PCM) microcapsules properties. The % PVP/St mass ratio was the most important parameter affecting the particle size distribution. The thermal energy storage of microcapsules increases with the PRS/ St mass ratio used. The following synthesis conditions, mass ratios PRS/St of 1.02, % PVP/St of 9.43, and H2O/St of 8.23, allowed the the proper main particle size in number (4.80 µm) for fabrics applications containing the maximum phase change material encapsulated with a latent heat of 102.42 J/g to be achieved. 1. Introduction Phase change materials (PCMs) are a series of functional materials with storing and realizing energy properties when experiencing a phase transition. The PCM material confinement by microencapsulation facilitates their incorporation into a wide variety of applications such as in fibers, fabrics, coatings, physiotherapy devices, insulation panels, and walls. 1 The textile industry has been slow to react to the possibilities of microencapsulation, although in the early 1980s phase change materials were used by the US National Aeronautics and Space Administration (NASA) with the aim of managing the thermal barrier properties of space suits. 2 The number of commercial applications of microencapsulation of PCMs in the textile industry continues to grow into textiles with new properties and added value, for instance, medical textiles and technical textiles. Textiles containing PCMs help to counteract cold and overheating; in general, this effect can be described as thermoregulation. For use in textile materials, an appropriate particle size should range from 0.5 to 100 µm. 3 Colvin and Bryant 4 used microcapsules containing PCMs of 30-100 µm for textile fibers, composites, and foams. Pause 5 made PCM microcapsules of 1-60 µm for nonwoven protective garments with thermoregulating properties. Shin et al. 6 prepared microcapsules

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