RESUMEN
This study aimed to assess the in vitro and in vivo disinfectant potential of peracetic acid (PAA) (1 mg/L) and hydrogen peroxide (H2O2) (20 mg/L) on the physicochemical and microbiological water quality parameters of fish aquaria, the microbial density of Nile tilapia muscular tissue, fish hepatic cortisol levels, and antioxidant biomarkers. In vitro, PAA and H2O2 reduced A. hydrophila colony viability by 5 log units after 30 and 5 min of contact time, respectively. PAA and H2O2 were added to aquaria water twice a week for the three-week experiment. Increased fish escape reflexes were observed only in the PAA group, which returned to normal within 10 min. No mortalities were reported in either the PAA or H2O2 groups. An in vivo experimental challenge with a pathogenic strain of A. hydrophila revealed a 20% reduction in mortality in the PAA group, with no mortalities in the H2O2 group. Cortisol levels and antioxidant markers were measured to assess the impact of PAA and H2O2 on fish health. Cortisol levels in the PAA and H2O2 groups were significantly higher than in the control group after disinfectant exposure, but they progressively returned to normal. A significant reduction in superoxide dismutase (SOD) and catalase (CAT) activity, along with considerably higher glutathione peroxidase (GPx) and malondialdehyde (MDA) enzymatic activity, was observed in the PAA and H2O2 groups compared to the control group. A substantial increase in total antioxidant capacity (TAC) was recorded in the PAA group. Physicochemical analyses revealed reduced pH and increased dissolved oxygen levels in the PAA and H2O2 groups. Microbiological analyses showed a significant reduction in bacterial density in water by 64% and 76% after 30 min of exposure to PAA and H2O2, respectively, with a non-significant increase in microbial count after bacterial challenge. Additionally, aerobic bacterial count, Aeromonas spp., and psychotropic bacterial count in fish muscle showed a significant reduction in the H2O2 group compared to the PAA and control groups before and after infection. The study concludes that regular application of PAA and H2O2 can temporarily reduce bacterial load in aquaria and fish muscle, regulate stress responses, and improve fish health by reducing A. hydrophila-induced infections and improving survival.
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Aeromonas hydrophila , Biomarcadores , Cíclidos , Desinfectantes , Enfermedades de los Peces , Peróxido de Hidrógeno , Ácido Peracético , Animales , Ácido Peracético/farmacología , Peróxido de Hidrógeno/metabolismo , Desinfectantes/farmacología , Cíclidos/metabolismo , Cíclidos/microbiología , Aeromonas hydrophila/efectos de los fármacos , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/prevención & control , Biomarcadores/metabolismo , Calidad del Agua , Hidrocortisona/metabolismo , Infecciones por Bacterias Gramnegativas/veterinaria , Infecciones por Bacterias Gramnegativas/microbiología , Antioxidantes/metabolismo , Estrés Fisiológico/efectos de los fármacos , Antibacterianos/farmacologíaRESUMEN
Pyrite has been widely utilized to activate oxidants for water treatment, yet the regulation of reactive oxygen species (ROS) by sulfur sites on its surface has been overlooked. In this study, the surface sulfur sites were regulated by thermal modification of natural pyrite in the N2 atmosphere (denoted as P-X, where X represented pyrolysis temperatures ranging from 400 to 700 °C), and these modified pyrites were employed to activate peracetic acid (PAA) for ciprofloxacin (CIP) degradation. The results revealed that the degradation rate of CIP increased as the reduced sulfur content increased, with the P600/PAA system achieving the highest apparent degradation rate (kobs = 0.0999 min-1). Quenching experiments and electron paramagnetic resonance (EPR) analysis identified various ROS involved in the P-X/PAA system, with hydroxyl radical (·OH) and singlet oxygen (1O2) identified as dominant reactive species responsible for CIP degradation. The reduced sulfur sites served as the primary active sites facilitating the conversion of organic radicals (·CH3C(O)OO) into superoxide radicals (·O2-) and 1O2. Furthermore, the P600/PAA system demonstrated robust adaptability under both acidic and neutral pH conditions, efficiently degrading CIP even in the presence of complex matrices such as Cl-, NO3-, SO42-, NH4+, or humic acid (HA) in water bodies, although HCO3- was found to inhibit CIP degradation. This study significantly enhances our understanding of the interaction between reduced sulfur sites and ROS in PAA-based advanced oxidation processes (AOPs), offering a promising technology for efficient antibiotic treatment in water purification.
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Ciprofloxacina , Ácido Peracético , Sulfuros , Azufre , Contaminantes Químicos del Agua , Ciprofloxacina/química , Azufre/química , Ácido Peracético/química , Contaminantes Químicos del Agua/química , Sulfuros/química , Oxígeno Singlete/química , Hierro/química , Especies Reactivas de Oxígeno/metabolismo , Purificación del Agua/métodosRESUMEN
Effective methods for decontamination of Shiga toxin-producing Escherichia coli (STEC) on beef were evaluated by 48 mL spraying, 100 mL, and 500 mL flushing with ethanol, hydrogen peroxide, peracetic acid, acidified sodium chlorite, and sodium hypochlorite in this study. The flushing with 500 mL of 1,000 ppm peracetic acid was most effective, reducing pathogens by 2.8 log CFU/cm2, followed by 1,200 ppm acidified sodium chlorite. The spraying with 1,000 ppm peracetic acid reduced pathogens by 1.6 log CFU/cm2. The flushing with 500 mL of 200 and 500 ppm acidified sodium chlorite, and 50, 100, 200, and 500 ppm peracetic acid significantly reduced the STEC population compared with those treated with distilled water (p < 0.05), reducing pathogens by 2.1, 2.4, 1.6, 1.8, 2.1 and 2.4 log CFU/cm2, respectively. Additionally, the flushing with 500 mL of 200 and 500 ppm acidified sodium chlorite significantly changed the color of beef samples (p < 0.05), whereas 100-500 ppm peracetic acid did not significantly change the color (p > 0.05). The flushing with 500 mL of 200 and 500 ppm acidified sodium chlorite and 200 and 500 ppm peracetic acid significantly changed the odor of beef samples compared with those treated with distilled water (p < 0.05). There was no difference in the reduction of STEC population between peracetic acid treatment at 25 °C and 55 °C, with or without washing with sterilized distilled water after decontamination. Washing with distilled water after flushing with peracetic acid tended to reduce the odor of the samples. These results suggest that treatment with 100, 200, and 500 ppm peracetic acid, followed by washing with distilled water, might reduce the STEC population without retaining the odor of the sanitizer.
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Recuento de Colonia Microbiana , Descontaminación , Desinfectantes , Escherichia coli Shiga-Toxigénica , Escherichia coli Shiga-Toxigénica/efectos de los fármacos , Animales , Bovinos , Descontaminación/métodos , Humanos , Desinfectantes/farmacología , Microbiología de Alimentos , Ácido Peracético/farmacología , Contaminación de Alimentos/análisis , Contaminación de Alimentos/prevención & control , Carne Roja/microbiología , Higiene , Hipoclorito de Sodio/farmacología , Peróxido de Hidrógeno/farmacología , Manipulación de Alimentos/métodos , Seguridad de Productos para el ConsumidorRESUMEN
In this study, the transformation mechanisms of extracellular polymeric substances (EPS) during ultraviolet/peracetic acid (UV/PAA) disinfection were elucidated based on multiple molecular-level analyses. After UV/PAA disinfection, the contents of soluble EPS (S-EPS), loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) were reduced by 70.47 %, 57.05 % and 47.46 %, respectively. Fluorescence excitation-emission matrix-parallel factor and Fourier transform ion cyclotron resonance mass spectrometry analyses showed that during UV/PAA disinfection, EPS was transformed from the state characterized by high aromaticity, low saturation and low oxidation to the one with reduced aromaticity, increased saturation and higher oxidation. Specifically, sulfur-containing molecules (CHOS, CHONS, etc.) in EPS were converted into highly saturated and oxidized species (such as CHO), with the aromaticity index (AImod) decreasing by up to 53.84 %. Molecular characteristics analyses further indicated that saturation degree, oxidation state of carbon and molecular weight exhibited the most significant changes in S-EPS, LB-EPS and TB-EPS, respectively. Additionally, mechanistic analysis revealed that oxygen addition reaction was the predominant reaction for S-EPS (+O) and TB-EPS (+3O) (accounting for 31.78 % and 36.47 %, respectively), while the dealkylation was the main reaction for LB-EPS (29.73 %). The results were consistent with functional groups sequential responses analyzed by Fourier transform infrared and two-dimensional correlation spectroscopy, and were further verified by density functional theory calculations. Most reactions were thermodynamically feasible, with reaction sites predominantly located at functional groups such as CO, CO, CN and aromatic rings. Moreover, metabolomics analysis suggested that changes in metabolites in raw secondary effluent during UV/PAA disinfection were strongly correlated with EPS transformation. Our study not only provides a strong basis for understanding EPS transformation during UV/PAA disinfection at molecular-level but also offers valuable insights for the application this promising disinfection process.
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Desinfección , Ácido Peracético , Desinfección/métodos , Ácido Peracético/química , Rayos Ultravioleta , Matriz Extracelular de Sustancias Poliméricas/químicaRESUMEN
Peracetic acid (PAA) shows potential for use in drinking water treatment as an alternative to prechlorination, such as for mussel control and disinfection by-product precursor destruction, though its impact as a preoxidant during cyanobacterial blooms remains underexplored. Here, Microcystis aeruginosa inactivation and microcystin-LR and -RR release and degradation using PAA were explored. The toxin degradation rates were found to be higher in alkaline conditions than in neutral and acidic conditions. However, all rates were significantly smaller than comparable rates when using free chlorine. The inactivation of M. aeruginosa cells using PAA was faster at acidic pH, showing immediate cell damage and subsequent cell death after 15-60 min of exposure to 10 mg/L PAA. In neutral and alkaline conditions, cell death occurred after a longer lag phase (3-6 h). During cell inactivation, microcystin-LR was released slowly, with <35% of the initial intracellular toxins measured in solution after 12 h of exposure to 10 mg/L PAA. Overall, PAA appears impractically slow for M. aeruginosa cell inactivation or microcystin-LR and -RR destruction in drinking water treatment, but this slow reactivity may also allow it to continue to be applied as a preoxidant for other purposes during cyanobacterial blooms without the risk of toxin release.
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Toxinas Marinas , Microcistinas , Microcystis , Oxidación-Reducción , Ácido Peracético , Microcystis/efectos de los fármacos , Microcystis/metabolismo , Microcistinas/toxicidad , Microcistinas/metabolismo , Ácido Peracético/farmacología , Toxinas Marinas/toxicidad , Purificación del Agua/métodos , Concentración de Iones de Hidrógeno , Agua Potable/microbiología , Agua Potable/químicaRESUMEN
Peracetic acid (PAA) is an alternative disinfectant for saline wastewaters, and hypohalous acids are typically regarded as the reactive species for oxidation and disinfection. However, new results herein strongly suggest that reactive radicals instead of HOI primarily contributed to decontamination during PAA treatment of iodine-containing wastewater. The presence of I- could greatly accelerate the micropollutants (e.g., sulfamethoxazole (SMX)) transformation by PAA. Chemical probes experiments and electron paramagnetic resonance analysis demonstrate acetylperoxyl radical rather than reactive iodine species primarily responsible for SMX degradation. The kinetic model was developed to further distinguish and quantify the contribution of radicals and iodine species, as well as to elucidate the transformation pathways of iodine species. Density functional theory calculations indicated that the nucleophilic attack of I- on the peroxide bond of PAA could form unstable O-I bond, with the transition state energy barrier for radical generation lower than that for HOI formation. The transformation of iodine species was regulated by acetylperoxyl radical to generate nontoxic IO3-, greatly alleviating the iodinated DBPs formation in saline wastewaters. This work provides mechanistic insights in radical-regulated iodine species transformation during PAA oxidation, paving the way for the development of viable and eco-friendly technology for iodide containing water treatment.
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Yodatos , Yoduros , Oxidación-Reducción , Ácido Peracético , Ácido Peracético/química , Yodatos/química , Yoduros/química , Contaminantes Químicos del Agua/química , Descontaminación/métodos , Aguas Residuales/química , Cinética , Purificación del Agua/métodosRESUMEN
Sanitizer spray and brush roller treatments have been documented as an effective means of reducing Salmonella on the surface of produce. The purpose of this study was to evaluate the efficacy of chlorine (NaOCl), peroxyacetic acid (PAA), and chlorine dioxide (ClO2) sprays to reduce Salmonella populations on the surface of mangoes during washing with brush or polyvinyl chloride (PVC) rollers. Whole mangoes were spot inoculated with 100 µL of a rifampicin-resistant Salmonella (8 log CFU/mL) cocktail at the equator and dried for 1 h. Mangoes were washed with a lab-scale roller system with either ground water (control), or sanitizers (100 ppm NaOCl, 80 ppm PAA, or 5 ppm ClO2) for 0, 5, 15, 30, or 60 s (n = 15 mangoes). Dey/Engley buffer (100 mL) was used to rinse mangoes before plating on media supplemented with rifampicin. NaOCl, PAA, and ClO2 spray (except for ClO2 at 30 s) had significantly higher reduction on Salmonella population than water spray at all treatment times (P ≤ 0.05) when brush rollers were used. All tested sanitizers also achieved a significantly higher reduction than water at 5 s when PVC rollers were used (P ≤ 0.05). Salmonella reductions achieved by brush and PVC rollers was not statistically different (P > 0.05). After a 5 s treatment on brush and PVC rollers, NaOCl, PAA, and ClO2 spray had ca. 3.03 and 3.45 log, 3.96 and 3.28 log, and 2.54 and 2.00 log CFU/mango reductions, respectively, whereas water spray achieved 1.75 and 0.98 log CFU/mango reduction. Addition of sanitizers to spray water used during brush or PVC washing in mango packinghouses can reduce Salmonella on mango surfaces.
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Compuestos de Cloro , Recuento de Colonia Microbiana , Desinfectantes , Mangifera , Óxidos , Ácido Peracético , Cloruro de Polivinilo , Salmonella , Hipoclorito de Sodio , Mangifera/microbiología , Compuestos de Cloro/farmacología , Salmonella/efectos de los fármacos , Desinfectantes/farmacología , Óxidos/farmacología , Ácido Peracético/farmacología , Hipoclorito de Sodio/farmacología , Manipulación de Alimentos/métodos , Microbiología de AlimentosRESUMEN
Studies of classical microbiology rely on the average behaviour of large cell populations without considering that clonal bacterial populations may bifurcate into phenotypic distinct sub-populations by random switching mechanisms.Listeria monocytogenes exposure to sublethal stresses may induce different physiological states that co-exist (i.e., sublethal injury or dormancy) and present variable resuscitation capacity. Exposures to peracetic acid (PAA; 10-30 ppm; for 3 h), acetic acid and hydrochloric acid (AA and HCl; pH 3.0-2.5; for 5 h) at 20 °C were used to induce different physiological states in L. monocytogenes, Scott A strain. After stress exposure, colony growth of single cells was monitored, on Tryptic Soy Agar supplemented with 0.6 % Yeast Extract, using time-lapse microscopy, at 37 °C. Images were acquired every 5 min and were analyzed using BaSCA framework. Most of the obtained growth curves of the colonies were fitted to the model of Baranyi and Roberts for the estimation of lag time (λ) and maximum specific growth rate (µmax), except the ones obtained after exposure to AA pH 2.7 and 2.5 that were fitted to the Trilinear model. The data of λ and µmax that followed a multivariate normal distribution were used to predict growth variability using Monte Carlo simulations. Outgrowth kinetics after treatment with AA (pH 2.7 and 2.5; for 5 h at 20 °C), PAA (30 ppm; for 3 h at 20 °C) revealed that these stress conditions increase the skewness of the variability distributions to the right, meaning that the variability in lag times increases in favour of longer outgrowth. Exposures to AA pH 2.5 and 30 ppm PAA resulted in two distinct subpopulations per generation with different growth dynamics. This switching mechanism may have evolved as a survival strategy for L. monocytogenes cells, maximizing the chances of survival. Simulation of microbial growth showed that heterogeneity in growth dynamics is increased when cells are recovering from exposure to sublethal stresses (i.e. PAA and acidic conditions) that may induce injury or dormancy.
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Ácido Acético , Listeria monocytogenes , Ácido Peracético , Listeria monocytogenes/crecimiento & desarrollo , Listeria monocytogenes/efectos de los fármacos , Ácido Peracético/farmacología , Concentración de Iones de Hidrógeno , Ácido Acético/farmacología , Recuento de Colonia Microbiana , Microbiología de Alimentos , Ácido Clorhídrico/farmacología , Modelos Biológicos , Estrés FisiológicoRESUMEN
Electrochemical advanced oxidation processes (EAOPs) face challenging conditions in chloride media, owing to the co-generation of undesirable Cl-disinfection byproducts (Cl-DBPs). Herein, the synergistic activation between in-situ electrogenerated HClO and peracetic acid (PAA)-based reactive species in actual wastewater is discussed. A metal-free graphene-modified graphite felt (graphene/GF) cathode is used for the first time to achieve the electrochemically-mediated activation of PAA. The PAA/Cl- system allowed a near-complete sulfamethoxazole (SMX) degradation (kobs =0.49 min-1) in only 5 min in a model solution, inducing 32.7- and 8.2-fold rise in kobs as compared to single PAA and Cl- systems, respectively. Such enhancement is attributed to the occurrence of 1O2 (25.5 µmol L-1 after 5 min of electrolysis) from the thermodynamically favored reaction between HClO and PAA-based reactive species. The antibiotic degradation in a complex water matrix was further considered. The SMX removal is slightly susceptible to the coexisting natural organic matter, with both the acute cytotoxicity (ACT) and the yield of 12 DBPs decreasing by 29.4 % and 37.3 %, respectively. According to calculations, HClO accumulation and organic Cl-addition reactions are thermodynamically unfavored. This study provides a scenario-oriented paradigm for PAA-based electrochemical treatment technology, being particularly appealing for treating wastewater rich in Cl- ion, which may derive in toxic Cl-DBPs.
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Antibacterianos , Ácido Peracético , Aguas Residuales , Contaminantes Químicos del Agua , Aguas Residuales/química , Ácido Peracético/química , Antibacterianos/química , Contaminantes Químicos del Agua/química , Oxidación-Reducción , Electrólisis , Eliminación de Residuos Líquidos/métodos , Sulfametoxazol/químicaRESUMEN
Peracetic acid (PAA) has received increasing attention as an alternative oxidant for wastewater treatment. However, existing processes for PAA activation to generate reactive species typically require external energy input (e.g., electrically and UV-mediated activation) or catalysts (e.g., Co2+), inevitably increasing treatment costs or introducing potential new contaminants that necessitate additional removal. In this work, we developed a catalyst-free, self-sustaining bioelectrochemical approach within a two-chamber bioelectrochemical system (BES), where a cathode electrode in-situ activates PAA using renewable biogenic electrons generated by anodic exoelectrogens (e.g., Geobacter) degrading biodegradable organic matter (e.g., acetic acid) in wastewater at the anode. This innovative BES-PAA technique achieved 98 % and 81 % removal of 2 µM sulfamethoxazole (SMX) in two hours at pH 2 (cation exchange membrane) and pH 6 (bipolar membrane) using 100 µM PAA without external voltage. Mechanistic studies, including radical quenching, molecular probe validation, electron spin resonance (ESR) experiments, and density functional theory (DFT) calculations, revealed that SMX degradation was driven by reactive species generated via biogenic electron-mediated OO cleavage of PAA, with CH3C(O)OO⢠contributing 68.1 %, â¢OH of 18.4 %, and CH3C(O)O⢠of 9.4 %, where initial formation of â¢OH and CH3C(O)O⢠rapidly reacts with PAA to produce CH3C(O)OOâ¢. The presence of common water constituents such as anions (e.g., Cl-, NO3-, and H2PO4-) and humic acid (HA) significantly hinders SMX removal via the BES-PAA technique, whereas CO32- and HCO3- ions have a comparatively minor impact. Additionally, the study investigated the removal of various pharmaceuticals present in secondary treated municipal wastewater, attributing differences in removal efficiency to the selective action of CH3C(O)OOâ¢. This research demonstrates a novel PAA activation method that is ecologically benign, inexpensive, and capable of overcoming catalyst deactivation and secondary pollution issues.
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Electrodos , Electrones , Ácido Peracético , Ácido Peracético/química , Aguas Residuales/química , Contaminantes Químicos del Agua/química , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Catálisis , Preparaciones Farmacéuticas/químicaRESUMEN
A novel UV/oxalic acid functionalized corn straw biochar (OCBC)/peroxyacetic acid (PAA) system was built to degrade sulfadiazine from waters. 94.7 % of SDZ was removed within 30 min by UV/OCBC/PAA. The abundant surface functional groups and persistent free radicals (PFRs) on OCBC were responsible for these performances. Cyclic voltammetry (CV) and other characterization analysis revealed, under UV irradiation, the addition of OCBC served as electron donor, which might promote the reaction of electrons with PAA. The quenching and electron paramagnetic resonance (EPR) tests indicated that R-Oâ¢, 1O2 and â¢OH were generated. Theoretical calculations indicated sulfonamide bridge was vulnerable under the attacks of reactive species. In addition, high removal effect achieved by 5 reuse cycles and different real waters also suggested the sustainability of UV/OCBC/PAA. Overall, this study provided a feasible approach to remove SDZ with high mineralization efficiency, in addition to a potential strategy for resource utilization of corn straw.
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Carbón Orgánico , Ácido Oxálico , Ácido Peracético , Sulfadiazina , Rayos Ultravioleta , Zea mays , Zea mays/química , Carbón Orgánico/química , Ácido Peracético/química , Sulfadiazina/química , Ácido Oxálico/química , Transporte de Electrón , Contaminantes Químicos del Agua , Purificación del Agua/métodosRESUMEN
In this research, the effects of peracetic acid (PAA), polymeric flocculants, and their combined conditioning on improving the dewatering performance were comprehensively evaluated. The results showed that sludge cake moisture content, capillary suction time (CST), and specific resistance to filtration (SRF) were 70.6%, 48.1 s, and 3.42 × 1012 m/kg after adding 0.10 g/gMLSS PAA for 50 min, representing reductions of 12.60%, 40.32%, and 33.98%, respectively. Additionally, conditioning of sludge with polyferric sulfate (PFS), polyaluminum chloride (PAC), and cationic polyacrylamide (CPAM) enhanced sludge properties in the following order: CPAM > PAC > PFS. After the PAA oxidation and re-flocculation process, the optimal dosages of PFS, PAC, and CPAM were reduced to 1.5 g/L, 0.9 g/L, and 0.04 g/L, respectively. The sludge dewatering performance significantly improved, with sludge cake moisture content measuring 65.8%, 66.3%, and 61.7%, respectively. Moreover, the spatial multi-porous skeleton structures were formed via re-flocculation to improve the sludge dewatering. Furthermore, economic evaluation validated that the pre-oxidation and re-flocculation process could be considered an economically viable option. These research findings could serve as a valuable reference for practical engineering applications.
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Floculación , Ácido Peracético , Aguas del Alcantarillado , Aguas del Alcantarillado/química , Ácido Peracético/química , Oxidación-Reducción , Polímeros/química , Filtración , Eliminación de Residuos Líquidos/métodos , Porosidad , Resinas Acrílicas/químicaRESUMEN
Synergistic actions of peroxides and high-valent metals have garnered increasing attentions in wastewater treatment. However, how peroxides interact with the reactive metal species to enhance the reactivity remains unclear. Herein, we report the synergistic oxidation of peracetic acid (PAA) and permanganate(â ¦) towards micropollutants, and revisit the underlying mechanism. The PAA-Mn(VII) system showed remarkable efficiency with a 28-fold enhancement on sulfamethoxazole (SMX) degradation compared to Mn(â ¦) alone. Extensive quenching experiments and electron spin resonance (ESR) analysis revealed the generation of unexpected Mn(V) and Mn(VI) beyond Mn(III) in the PAA-Mn(VII) system. The utilization efficiency of Mn intermediates was quantified using 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonate (ABTS), and the results indicated that PAA could enhance the electron transfer efficiency of reactive manganese (Mn) species, thus accelerating the micropollutant degradation. Density functional theory (DFT) calculations showed that Mn intermediates could coordinate to the O1 of PAA with a low energy gap, enhancing the oxidation capacity and stability of Mn intermediates. A kinetic model based on first principles was established to simulate the time-dependent concentration profiles of the PAA-Mn complexes and quantify the contributions of the PAA-Mn(III) complex (50.8 to 59.3 %) and the PAA-Mn(â ¤/â ¥) complex (40.7 to 49.2 %). The PAA-Mn(VII) system was resistant to the interference from complex matrix components (e.g., chloride and humic acid), leading to the high efficiency in real wastewater. This work provides new insights into the interaction of PAA with reactive manganese species for accelerated oxidation of micropollutants, facilitating its application in wastewater treatment.
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Compuestos de Manganeso , Manganeso , Oxidación-Reducción , Óxidos , Ácido Peracético , Ácido Peracético/química , Manganeso/química , Compuestos de Manganeso/química , Óxidos/química , Contaminantes Químicos del Agua/químicaRESUMEN
The ecological impact of emerging contaminants (ECs) in aquatic environments has raised concerns, particularly with regards to urine as a significant source of such contaminants in wastewater. The current investigation used the UV/Peracetic Acid (UV/PAA) processes, an innovative advanced oxidation technology, to effectively separate two emerging pollutants from urine at its source, namely, ciprofloxacin (CIP) and bisphenol A(BPA). The research findings demonstrate that the presence of the majority of characteristic ions has minimal impact on the degradation of ECs. However, in synthetic hydrolyzed urine, only NH4+ inhibits the degradation of two types of ECs, with a more pronounced effect observed on CIP degradation compared to BPA.The impact of halogen ions, specifically Cl- and I-, on the degradation of CIP in synthetic hydrolyzed urine was a complex phenomenon. When these two halogen ions are present individually, the generation of reactive halogen species (RHS) within the system enhances the degradation of CIP. However, when both types of ions coexist, the formation of diatomic radical species partially inhibits degradation. In terms of BPA degradation, while the production of reactive chlorine species (RCS) to some extent hinders the reaction rate, the generation of reactive iodine species (RIS) promotes the overall process. CIP undergoes fragmentation of the piperazine and quinoline rings, decarboxylation, defluorination reactions, as well as substitution reactions, leading to the formation of products with simplified structures. The degradation of BPA occurs gradually through hydroxyl and halogen substitution as well as isopropyl cleavage. The preliminary toxicity analysis confirmed that the presence of halogen ions in urine resulted in the formation of halogenated products in two types of ECs, albeit with an overall reduction in toxicity. The UV/PAA processes was considered to be an effective and relatively safe approach for the separation of ECs in urine.
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Compuestos de Bencidrilo , Ácido Peracético , Fenoles , Contaminantes Químicos del Agua , Compuestos de Bencidrilo/química , Contaminantes Químicos del Agua/química , Ácido Peracético/química , Fenoles/química , Rayos Ultravioleta , Radicales Libres/química , Ciprofloxacina/química , Aguas Residuales/química , Orina/químicaRESUMEN
BACKGROUND: Pseudomonas aeruginosa is a leading cause of nosocomial Gram-negative bacteraemia. Water systems are a well-documented source of P. aeruginosa and established biofilms are difficult to remove. AIM: To evaluate the efficacy of regular flushing, peracetic acid disinfection, in-tap thermal disinfection, and in-line thermal disinfection to eradicate P. aeruginosa biofilm in a colonized tap model. METHODS: A simulated tap system was constructed and inoculated with a reference and an environmental strain of P. aeruginosa to form biofilm. Water samples were collected from the taps and P. aeruginosa levels enumerated following disinfection methods. To simulate regular flushing, taps were flushed for 5 min, five times per day with water tested daily. Peracetic acid (4000 ppm) was manually injected into the system and flushed through the system with a pump. Thermal flushing at 60 °C was performed in-line and with an in-tap bypass valve. Tests were conducted with cross-linked polyethylene (PEX) piping and repeated with copper piping. FINDINGS: Regular flushing and peracetic acid applied with a pump did not reduce P. aeruginosa levels. A limited reduction was observed when manually injecting peracetic acid. In-tap thermal flushing eradicated P. aeruginosa in copper piping but not PEX. In-line thermal flushing was the most effective at reducing P. aeruginosa levels; however, it did not eradicate the biofilm. CONCLUSION: In-line thermal flushing was the most effective method to remove P. aeruginosa biofilm. Results vary significantly with the strain of bacteria and the composition of the plumbing. Several methods used in combination may be necessary to remove established biofilm.
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Biopelículas , Desinfectantes , Desinfección , Ácido Peracético , Pseudomonas aeruginosa , Biopelículas/crecimiento & desarrollo , Biopelículas/efectos de los fármacos , Pseudomonas aeruginosa/fisiología , Pseudomonas aeruginosa/efectos de los fármacos , Desinfección/métodos , Ácido Peracético/farmacología , Desinfectantes/farmacología , Microbiología del Agua , HumanosRESUMEN
The periphery of the hospital water system interfaces at multiple points with patients and staff in clinical areas. This comprises mostly sinks and showers and presents a significant infection control risk. Wastewater drains in particular act as a reservoir of pathogens that can be transmitted to patients. Numerous strategies have been investigated as potential methods to reduce biofilm and bacterial load including regular application of biocidal chemicals. Traditional methods of assessing the efficacy of such products relies on culture-based microbiological techniques, usually targeting a limited range of key pathogens. We assessed the efficacy of a peracetic acid containing drain disinfectant product on seven clinical handwash basin drains, taking daily samples over six weeks (before, during and after use of the drain disinfectant product). We used a rapid, culture-independent estimation of total bacterial viable count (TVC) to assess efficacy. We applied long-read metagenomic sequencing to study the entire drain microbiome, which allowed taxonomic changes to be documented following use of the drain disinfectant product. All samples were found to be heavily contaminated, however the drain disinfectant product reduced the TVC from an estimated mean of 4228 cfu/mL to 2874 cfu/mL. This reduction was sustained in the two weeks following cessation of the product. Long-read metagenomic sequencing showed a microbiome dominated with Gram-negative organisms, with some taxonomic shifts in samples before and after application of the drain disinfectant. The impact on hospital-acquired infections from reducing bioburden in hospital drains by approximately a third, along with any associated changes in bacterial composition, needs evaluation in future studies.
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Carga Bacteriana , Desinfectantes , Hospitales , Ácido Peracético , Aguas Residuales , Ácido Peracético/farmacología , Desinfectantes/farmacología , Humanos , Aguas Residuales/microbiología , Bacterias/efectos de los fármacos , Bacterias/clasificación , Bacterias/aislamiento & purificaciónRESUMEN
Salmonella is a common cause of human foodborne illness, which is frequently associated with consumption of contaminated or undercooked poultry meat. Serotype Infantis is among the most common serotypes isolated from poultry meat products globally. Isolates of serotype Infantis carrying the pESI plasmid, the most dominant strain of Infantis, have been shown to exhibit oxidizer tolerance. Therefore, 16 strains of Salmonella with and without pESI carriage were investigated for susceptibility to biocide chemical processing aids approved for use in US poultry meat processing: peracetic acid (PAA), cetylpyridinium chloride (CPC), calcium hypochlorite, and sodium hypochlorite. Strains were exposed for 15 s to simulate spray application and 90 min to simulate application in an immersion chiller. All strains tested were susceptible to all concentrations of PAA, CPC, and sodium hypochlorite when applied for 90 min. When CPC, calcium hypochlorite, and sodium hypochlorite were applied for 15 s to simulate spray time, strains responded similarly to each other. However, strains responded variably to exposure to PAA. The variation was not statistically significant and appears unrelated to pESI carriage. Results highlight the necessity of testing biocide susceptibility in the presence of organic material and in relevant in situ applications.
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Desinfectantes , Ácido Peracético , Plásmidos , Aves de Corral , Salmonella , Hipoclorito de Sodio , Desinfectantes/farmacología , Animales , Salmonella/efectos de los fármacos , Salmonella/genética , Ácido Peracético/farmacología , Hipoclorito de Sodio/farmacología , Plásmidos/genética , Aves de Corral/microbiología , Cetilpiridinio/farmacología , Compuestos de Calcio/farmacología , Microbiología de Alimentos , Humanos , Pruebas de Sensibilidad Microbiana , Manipulación de AlimentosRESUMEN
The activated sludge process plays a crucial role in modern wastewater treatment plants. During the treatment of daily sewage, a large amount of residual sludge is generated, which, if improperly managed, can pose burdens on the environment and human health. Additionally, the highly hydrated colloidal structure of biopolymers limits the rate and degree of dewatering, making mechanical dewatering challenging. This study investigates the impact and mechanism of microwave irradiation (MW) in conjunction with peracetic acid (PAA) on the dewatering efficiency of sludge. Sludge dewatering effectiveness was assessed through capillary suction time (CST) and specific resistance to filtration (SRF). Examination of the impact of MW-PAA treatment on sludge dewatering performance involved assessing the levels of extracellular polymeric substances (EPS), employing three-dimensional excitation-emission matrix (3D-EEM), Fourier transform-infrared spectroscopy (FT-IR), and scanning electron microscopy. Findings reveal that optimal dewatering performance, with respective reductions of 91.22% for SRF and 84.22% for CST, was attained under the following conditions: microwave power of 600 W, reaction time of 120 s, and PAA dosage of 0.25 g/g MLSS. Additionally, alterations in both sludge EPS composition and floc morphology pre- and post-MW-PAA treatment underwent examination. The findings demonstrate that microwaves additionally boost the breakdown of PAA into â¢OH radicals, suggesting a synergistic effect upon combining MW-PAA treatment. These pertinent research findings offer insights into employing MW-PAA technology for residual sludge treatment.
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Microondas , Ácido Peracético , Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aguas del Alcantarillado/química , Ácido Peracético/química , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/química , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Effective disinfection methods are crucial in the cold chain transportation process of food due to the specificity of temperature and the diversity of contaminated flora. The objective of this study was to investigate the sanitizing effect of different disinfectants on various fungi at - 20 °C to achieve accurate disinfection of diverse bacterial populations. Peracetic acid, hydrogen peroxide, and potassium bisulfate were selected as low-temperature disinfectants and were combined with antifreeze. The sanitizing effect of these cryogenic disinfectants on pathogens such as Bacillus subtilis black variant spores (ATCC9372), Staphylococcus aureus (ATCC 6538), Candida albicans (ATCC 10231), Escherichia coli (8099), and poliovirus (PV-1) was sequentially verified by bactericidal and virus inactivation experiments. After a specified time of disinfection, a neutralizing agent was used to halt the sanitizing process. The study demonstrates that different disinfectants exhibit selective effects during the low-temperature disinfection process. Peracetic acid, hydrogen peroxide, and potassium monopersulfate are suitable for the low-temperature environmental disinfection of bacterial propagules, viruses, and fungal contaminants. However, for microorganisms with strong resistance to spores, a low-temperature disinfectant based on peracetic acid should be chosen for effective disinfection treatment. Our results provide a valuable reference for selecting appropriate disinfectants to sanitize various potential pathogens in the future.
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Frío , Desinfectantes , Desinfección , Peróxido de Hidrógeno , Ácido Peracético , Desinfectantes/farmacología , Desinfección/métodos , Peróxido de Hidrógeno/farmacología , Ácido Peracético/farmacología , Sulfatos/farmacología , Bacillus subtilis/efectos de los fármacos , Compuestos de Potasio/farmacología , Staphylococcus aureus/efectos de los fármacos , Candida albicans/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Poliovirus/efectos de los fármacosRESUMEN
Exposure to sublethal stresses related to food-processing may induce a heterogenous mixture of cells that co-exist, comprising healthy, sublethally injured, dormant and dead cells. Heterogeneity in survival capacity and dormancy of single cells may impede the detection of foodborne pathogens. In this study, we exposed Listeria monocytogenes Scott A strain, to peracetic acid (PAA; 20-40 ppm) and to acidic conditions (hydrochloric (HCl) and acetic (AA) acid, adjusted to pH 2.7-3.0, to evaluate the resuscitation capacity and outgrowth kinetics of metabolically active cells in two different media. Injury and the viable-but-non-culturable (VBNC) status of cells were assessed by flow cytometry using CFDA (metabolically active) and PI (dead) staining. Stressed CFDA+PI- cells were sorted on Tryptic Soy (TS) Agar or in TS broth, both supplemented with 0.6 % Yeast Extract (TSAYE or TSBYE), to evaluate culturability. Resuscitation capacity of CFDA+PI-sorted cells (10 events/well) was monitored by visual inspection on TSAYE and by optical density measurement in TSBYE for 5 days. Sorting of L. monocytogenes viable cells (CFDA+PI-) in Ringer's solution on TSAYE and TSBYE showed 100 % recovery in both media (control condition), while the mean lag time in TSBYE was 9.6 h. Treatment with 20 ppm PAA for 90 and 180 min resulted in 74.79 % and 85.82 % of non-culturable cells in TSBYE and increased the average lag time to 41.7 h and 43.8 h, respectively, compared to the control (9.6 h). The longest average lag time (79.5 h) was detected after treatment with 30 ppm PAA for 90 min, while at the same condition sorting of CFDA+PI- cells resulted in 95.05 % and 93.94 % non-culturable cells on TSAYE and TSBYE, respectively. The highest percentage of wells with non-culturable cells (96.17 %) was detected on TSAYE after treatment with 40 ppm PAA for 30 min. Fractions of VBNC cells were detected in TSBYE after treatment with HCl pH 3.0 for 60 and 240 min, and in TSAYE and TSBYE after exposure to AA pH 2.7. Treatment with AA pH 2.7 for 150-300 min increased the range of recorded lag time values compared to 60 min, from 8.6 h up to 13.3 h, as well as the mean lag times in TSBYE. Modelling of the outgrowth kinetics comparing the two types of stress (oxidative vs acid) and the two systems of growth (colonial vs planktonic) revealed that low starting concentrations hindered the detection of viable L. monocytogenes cells, either due to VBNC induction or cell heterogeneity.