Comparison of different wastewater treatments for colour removal of reactive dye baths

The generation of high-coloured wastewater is one of the main environmental problems of the textile industry. Reactive dyes are widely used in the dyeing of cellulosic fibres. However, they have low exhaustion degree (70–90%). The degradation of residual dyes by aerobic biological treatment is very poor, being necessary the application of specific treatments. In this work, three different methods for the removal of reactive dyes were compared: electrochemical treatment, coagulation with Moringa oleifera waste and enzymatic treatment with laccase. Two azo bifunctional dyes with different reactive groups were selected: C.I. Reactive Black 5 (vinyl sulphone) and C.I. Reactive Red 231 (chlorotriazine). The influence of pH (5 and 9) and dye hydrolysis on the decolourisation yield was studied. The electrochemical treatment was the most efficient, with 95–100% colour removal yield. The coagulation with M. oleifera waste also achieved high colour removal efficiency (91–94%). Both methods showed an independent behaviour with respect to pH or dye hydrolysis. The enzymatic treatment should be performed at pH 5. This method was suitable to remove the chlorotriazine dye (92–93% efficiency), whereas the vinyl sulphone one showed a marked dependence on dye hydrolysis: moderately efficient for the hydrolysed dye and highly efficient without hydrolysis. The activity of laccase was not modified by the usual salinity of the reactive dyeing effluent (20 g/L NaCl). Nevertheless, the effluent salinity enhanced the electrochemical and M. oleifera treatment yield.Peer ReviewedPostprint (author’s final draft

Biodégradabilité des effluents textiles traités avec des techniques d'oxydation électrochemique

La oxidación electroquímica de efluentes textiles es un método eficaz para la eliminación del color, especialmente cuando el agua residual contiene colorantes reactivos. Sin embargo, antes de la aplicación industrial de esta técnica, deben llevarse a cabo controles para verificar que no se genere una cantidad excesiva de productos tóxicos durante el tratamiento. En este estudio, los efluentes tratados por oxidación electroquímica son aguas residuales textiles sintéticas que contienen colorantes reactivos. Para evaluar su biodegradabilidad, se emplean técnicas respirométricas. Cuando el ión cloruro está presente en el agua residual coloreada, el tratamiento electroquímico puede proporcionar una buena eliminación del color a un coste bajo. En general, el nivel de biodegradabilidad de las aguas residuales aumenta después del tratamiento electroquímico para la eliminación del color siempre que vaya seguido de una aireación para eliminar el cloro. En ausencia del ión cloruro, no se requiere aireación debido a que durante el tratamiento electroquímico, la biodegradabilidad mejora.In a previous paper, the electrochemical oxidation of textile effluents was reported as an efficient method to remove colour, especially when the wastewater contains reactive dyes. However, before applying industrially this technique, some controls should be carried out in order to verify that no exceeding amounts of toxic products are generated during the treatment. In the present work, effluents treated by electrochemical oxidation are the synthetic textile wastewater containing reactive dyes. Respirometric techniques are employed to evaluate the biodegradability. When chloride ion is present in a dyeing wastewater, an electrochemical treatment can achieve a good colour removal with a reasonable cost. In general, wastewater keeps their biodegradability level after removing colour by an electrochemical treatment, whenever this treatment is followed by an aeration to eliminate the chlorine. In the absence of chloride ion, the aeration is not required since the biodegradability is improved during the electrochemical treatment.Dans un travail préalable, l'oxydation électrochimique d'effluents textiles a été rapportée comme une méthode effective pour décolorer les eaux résiduaires, surtout quand elles contiennent des colorants réactifs. Cependant, quelques contrôles devraient être emportés pour vérifier, avant d'appliquer cette technique industriellement, que la quantité de produits toxiques qui peut se produire pendant le traitement ne soit pas excessive. Dans la présente étude, les effluents traités par oxydation électrochimique sont des eaux résiduaires textiles synthétiques qui contiennent des colorants réactifs. Des techniques respirometriques sont employées pour évaluer leur biodégradabilité. Quand l'ion chlorure est présent dans une eau résiduaire de teinture, un traitement électrochimique peut accomplir une bonne décoloration avec un coût raisonnable. En général, les eaux résiduaires maintiennent leur biodégradabilité après avoir éliminé la couleur par un traitement électrochimique, pourvu que ce traitement soit suivi d’une aération pour enlever le chlore. En absence d'ion chlorure, l'aération n'est pas exigée puis ce que la biodégradabilité augmente pendant le traitement électrochimique

Respirometric study of optical brighteners in textile wastewater

Optical brighteners (OBs) are colorless fluorescent dyes, widely used in industry to improve whiteness in materials. Nearly 80% of all OBs in the market are derivatives of stilbene. They absorb the near-ultraviolet light and re-emit most of it in the blue range as visible fluorescence. OBs are commonly applied on textiles, detergents, paper and plastic products, among others. OBs have a low degradation ratio. In biological plants, they can only be partially removed by adsorption into the sludge and a tertiary treatment could be required to fully remove them. Part of them may persist and can be found in river and lake waters. The current work aims to evaluate the effect of the OBs in the bacterial activity of biological wastewater treatment plants. The influence of two commercial OBs (Goldblanc BHA and Leucophor PC) on respiration rate was monitored by means of a semi-continuous electrolytic respirometer, in order to obtain information related to the growth of the biomass and the degradation of the substrate. Their acute toxicity was also determined. It was concluded that the OB effect on bacteria population is variable depending on its chemical structure. Unlike the former, the Leucophor-PC brightener had an impact on the respirometric rate.Peer ReviewedPostprint (published version

Métodos de eliminación del color en efluentes de tintura textil

La industria textil por vía húmeda genera grandes cantidades de agua residual en sus procesos productivos, principalmente en las operaciones de ennoblecimiento (preparación, tintura y acabado). El sector textil precisa de tratamientos primarios, secundarios y tratamientos avanzados para eliminar la materia orgánica, sólidos no eliminados anteriormente y el color. En especial, la eliminación de los colorantes en este tipo de efluentes representa un reto tecnológico en los procesos de tratamiento de aguas residuales. Se estima que mundialmente se descargan 280.000 toneladas de colorantes en los efluentes textiles. La compleja mezcla de colorantes y compuestos que se emplean para el acabado, hace que las aguas residuales de la industria textil sean difíciles de tratar sólo por medio de sistemas biológicos o fisicoquímicos convencionales, por lo que se requieren estudios de tecnologías innovadoras para completar la depuración. The wet textile industry generates large amounts of waste water in their production processes, especially in finishing operations (preparation, dyeing and finishing). Conventional technologies for colour removal are being implemented on an industrial scale, offering good levels of discoloration, but all have in common, their high cost. Recently, many research groups worldwide are working on a laboratory scale and pilot plant in what may be termed as “New technologies for colour removal”, although some of them are based on traditional methodsPostprint (author’s final draft

Biodegradabilidad, toxicidad y acumulación del colorante acido azul omegacromo en la trucha arco iris "Salmo Gairdneri".

Se estudia el impacto ambiental producido por el colorante de tintura Azul Omegocromo B. Se determina: su biodegradabilidad en condiciones aerobias, su toxicidad en la trucha arco iris "Salmo gairdnen" en condiciones agudas y subagudas y la acumulación en vanos órganos (branquias, hígado, pancreas y músculo) para las ditintas dosis en el tratamiento subagudo.The environmental impact caused by the Omegachrome Blue B dye is studied. The following parameters have been determinated: its biodegradability under aerobic conditions, its toxiaty in the rainbow trout "Salmo gairdneri" under acute and subacute conditions and the accumulation in come organs (gill, liver pancreas and muscle) for different doses in the subacute treatment.On étudie l'impact ambientale produit par le colorant Bleu Omegachrome B. On determine la biodegradabilite en moyen aerobie, la toxicité sur la truite arcen.ciel "Salmo gairdnen" aigüe et subagüe et l'accumulation dans divers organes (branchies, foie, pancreas et muscle) a plusieures doses a l'essai subaigu.Peer Reviewe

Biological treatment of a textile effluent after electrochemical oxidation of reactive dyes

Electronic version of an article published as "Water environment research", vol.82, no.2, 2010,p.176-182. DOI No:10.2175/106143009X447902In this work, a synthetic textile effluent containing a reactive dye (C.I. Reactive Orange 4) was treated in an electrochemical cell with titanium covered by platinum oxide (Ti/PtOx) electrodes to remove color. The discolored effluent was mixed with other textile mill process effluents (scouring, bleaching, washing, etc.), according to the rate of each effluent in the mill, and was submitted to biological treatment (activated sludge plant). Two biological plants were run simultaneously to evaluate the influence of oxidant products generated during the electrochemical treatment. The final chemical oxygen demand (COD) removal in both plants was 65 to 72%. The yield of the activated sludge plants was not affected by the addition of 10% of the discolored dyeing effluent (even when oxidants products were not removed), which indicates that the previous electrochemical treatment do not produce inhibition effects on the biological plant. However, in the case of direct addition of the discolored effluent, the biological treatment plant required a longer adaptation period. In addition, the electrolytic respirometry tests showed that all the biodegradable organic matter was removed, which implies that the yield in organic matter removal was the maximum possible for this type of treatment.Peer ReviewedPostprint (published version

Influence of a mixture of metals on PAHs biodegradation processes in soils

In order to assess the effect of mixed pollutants, the influence of different concentration levels of a mixture of metals (Cr, Co, Pb, Mn, Ni, Cu, Zn) on the biodegradation of some PAHs (phenanthrene, fluoranthene, pyrene, benzo[b]fluoranthene and benzo[a]pyrene) in soil samples was evaluated. To do so, groups of microcosms of a natural soil fromthe region of Sabadell (Barcelona, Spain)were prepared as a reproduction of the native environment at laboratory scale, under controlled conditions. Mixtures of PAHs and metals were carefully selected, according to soil characterization and microbiological growth preliminary assays, and were added to microcosms. These microcosms were analyzed at various times, along two months, to obtain PAHs dissipation time-courses. A first-order kinetic modelling allowed obtaining different rate constants and DT50 values as a function of the metal levels introduced in microcosms. As a general observation, the higher the concentration of metals, the lower the biodegradation of PAHs of 3–4 rings (phenanthrene, fluoranthene and pyrene). On the other hand, no important effect on the biodegradation of higher molecular weight PAHs (benzo[b]fluoranthene and benzo[a]pyrene) was observed at the different concentration levels of metals testedPostprint (author's final draft

Mutations in the urocanase gene UROC1 are associated with urocanic aciduria

[EN] Urocanase is an enzyme in the histidine pathway encoded by the UROC1 gene. This report describes the first putative mutations, p. L70P and p.R450C, in the coding region of the UROC1 gene in a girl with urocanic aciduria presenting with mental retardation and intermittent ataxia. Computed (in silico) predictions, protein expression studies and enzyme activity assays suggest that none of the mutations can produce a fully functional enzyme. The p. L70P substitution, which probably implies the disruption of an alpha-helix in the N-terminus, would alter its properties and therefore, its function. The p.R450C change would render impossible any interaction between urocanase and its substrate and would loss its enzyme activity. Consequently, these studies suggest that both mutations could alter the correct activity of urocanase, which would explain the clinical and biochemical findings described in this patient.We are grateful to the patient for her kind collaboration. We are indebted to Dr C Marco-Marín for the in silico structural studies. CIBERER is an initiative of the Instituto de Salud Carlos III. This work was supported by grants from the Fondo de Investigación Sanitaria (PI051318 and PI070548).Espinós-Armero, CÁ.; Pineda, M.; Martínez-Rubio, D.; Aída Ormazabal; María Antonia Vilaseca; Leo J. M. Spaapen; Palau, F.... (2009). Mutations in the urocanase gene UROC1 are associated with urocanic aciduria. Journal of Medical Genetics. 46(6):407-411. https://doi.org/10.1136/jmg.2008.06063240741146

Electrical Conductivity Response of Poly(Phenylene-vinylene)/Zeolite Composites Exposed to Ammonium Nitrate

Poly(p-phenylenevinylene) (PPV) was chemically synthesized via the polymerization of p-xylene-bis(tetrahydrothiophenium chloride) monomer and doped with H2SO4. To improve the electrical conductivity sensitivity of the conductive polymer, Zeolites Y (Si/Al = 5.1, 30, 60, 80) were added into the conductive polymer matrix. All composite samples show definite positive responses towards NH4NO3. The electrical conductivity sensitivities of the composite sensors increase linearly with increasing Si/Al ratio: with values of 0.201, 1.37, 2.80 and 3.18, respectively. The interactions between NH4NO3 molecules and the PPV/zeolite composites with respect to the electrical conductivity sensitivity were investigated through the infrared spectroscopy

The incidence of clinical fractures in adults aged 50 years and older in Spain

Objective. The aim of this study was to quantify the incidence of all clinical fractures, including traumatic and fragility fractures, in patients aged 50 years and older, and to describe their distribution by fracture location, sex and age. Methods. The incidence of clinical fractures at 10 hospitals in Catalonia, with a reference population of 3 155 000 inhabitants, was studied. For 1 week, from 30 May to 5 June 2016, we reviewed the discharge reports of the Traumatology section of the Emergency Department to identify all fractures diagnosed in patients ≥50 years of age. As a validation technique, data collection was carried out for 1 year at one of the centres, from 1 December 2015 to 30 November 2016. The fracture incidence, including the 95% CI, was estimated for the entire sample and grouped by fracture type, location, sex and age. Results. A total of 283 fractures were identified. Seventy per cent were in women, with a mean age of 72 years. The overall fracture incidence was 11.28 per 1000 person-years (95% CI: 11.10, 11.46), with an incidence of traumatic and fragility fractures of 4.15 (95% CI: 4.04, 4.26) and 7.13 per 1000 person-years (95% CI: 6.99, 7.28), respectively. The incidence of fractures observed in the validation sample coincided with that estimated for the whole of Catalonia. The most common fragility fractures were of the hip, forearm, humerus and vertebrae. Conclusion. The results of this study are the first to estimate the incidence of clinical fragility fractures in Spain, grouped by location, age and sex