127 research outputs found
Biodegradation of ethyl acetate and toluene mixtures by a peat biofilter: respirometry monitoring and dynamics of living and dead bacterial cells
Performance of peat biofilters treating ethyl acetate and toluene mixtures under non-steady-state conditions
[Abstract] This paper presents the response of peat biofilters to loading changes corresponding to industrial practices such as overnight and weekend shutdowns, intermittent emission or inlet concentration peaks. Three laboratory-scale reactors fed with air contaminated with ethyl acetate, toluene or a 1:1 mixture of ethyl acetate and toluene were operated under 65 g m-3 h-1 inlet load and 60 s EBRT during 16 h/day, 5 days/week. Dynamic behavior after feed resumption after night and weekend closures showed a 1-2 h period of transient response to recover stable CO2 production values. No increase in VOC emission was observed, except for biofilters treating toluene for which a transient peak in VOC emission during 4-8 h after weekend closures was detected. More stressful conditions such as intermittent emissions (2 h-on/ 2 h-off, 16 h/day, 5 days/week), or inlet concentration peaks (40-min, 50% increase) were successfully handled in the biofilter treating only ethyl acetate; but deterioration in the operation was observed in presence of toluene. The system performance after 15-days starvation period was fully recovered in less than 8 h of re-acclimation period. Living and dead cells monitoring results are also presented
Start-up evaluation of a peat biofilter treating waste gas contaminated with ethyl acetate by using two strategies: without inoculation and with inoculation
Removal of a mixture of oxygenated VOCs in a biotrickling filter
[Abstract] Laboratory scale-studies on the biodegradation of a 1:1:1 wt mixture of three oxygenated volatile organic compounds (VOCs), ethanol, ethyl acetate and methyl-ethyl ketone (MEK) in a biotrickling filter were carried out using two identically sized columns, filled with different polypropylene rings. The reactors were seeded with a two-month preconditioned culture from activated sludge. The performance of the biotrickling filters was examined for a continuous period of 4 months at VOC concentration from 125 mg-C/m3 to 550 mg-C/m3 and at gas flow rates of around 1.0 m3/h, 2.0 m3/h and 4.6 m3/h, which correspond to gas empty bed residence times (EBRT) of 68 s, 33 s and 16 s, respectively. Similar performance was obtained for both supports. Intermittent flow rate of trickling liquid was shown as beneficial to improve the removal efficiency of the system. A stratification in the substrate consumption was observed from gas composition profiles, with MEK % in the emission greater than 78%. Continuous VOC feeding resulted in an excessive accumulation of biomass and high pressure drop was developed in less than 20-30 days of operation. Intermittent VOC loading with night and weekend feed cut-off periods passing dried air, but without water addition, was shown as a successful operational mode to control the biofilm thickness. In this case, operation at high inlet loads was extended for more than 50 days maintaining high removal efficiencies and low pressure drops
Membrane-assisted reactive crystallisation for the recovery of dissolved phosphorus in vivianite form from liquid effluents
Novel membrane crystallisation processes resolve the mixing challenge on conventional crystallisers, by providing fixed interfacial area over which supersaturation is controlled for nucleation. Moreover, the membrane surface is thought to reduce interfacial energy and encourage micromixing. In this regard, a novel membraneassisted reactive crystallisation (MARC) process was used in this work for the dissolved phosphorous recovery in form of vivianite crystals from a phosphate-rich solution by means of the dosing of iron (II). To characterise the role of the boundary layer in controlling nucleation, a batch lab-scale system was used for the crystallization tests, and different hydraulic conditions (Reynolds ranging from 105 to 395) and polymeric membranes were tested. The crystallisation process was influenced by the hydraulic conditions, in which a low liquid velocity led to a lower induction time and vivianite supersaturation, and therefore, higher nucleation rates. Membrane properties were characterised to establish their role in the modification of the critical free energy requirement for nucleation, and for the promotion of micromixing, as possible factors that can be used to modify nucleation kinetics. As result, the bulk induction time tended to decrease with the increase in membrane hydrophobicity, roughness, pore size and porosity. Spherical vivianite nanoparticles were always synthesised with a mean size around 35 nm and a narrow distribution independently of the hydraulic conditions and membrane used. Finally, the crystallisation kinetic conformed to a diffusion-dependent nucleation mechanism, in which higher residence times for mixing increased the ion collision probability for nucleation. Importantly, this study demonstrated that MARC is an attractive prospect for nutrient recovery from wastewaters where crystal nucleation can be easily controlled by setting the operational conditions and membrane properties, eliciting considerable process intensification over existing conventional crystalliser.European Union funding: 71408
Impact of power ultrasound on chemical and physicochemical quality indicators of strawberries dried by convection
[EN] A study on the quality parameters of strawberries dehydrated by convection assisted by power ultrasound
(US) at 40 70 C and 30 and 60W has been carried out for the first time. In general, the quality
of US-treated samples was higher than that of commercial samples. Even under the most severe conditions
used (US at 70 C and 60 W), high values of vitamin C retention (>65%) and scarce advance of Maillard
reaction (2-furoylmethyl derivatives of Lys and Arg < 90 mg 100 g 1 protein) were observed.
Rehydration ratio was not affected by the power applied and the obtained values were similar to those
of convectively-treated samples. According to the results here presented, US is a suitable example of
an emerging and environmentally friendly technology that accelerates convective drying, allowing the
obtainment of dried strawberries with premium quality.This work has been funded by Ministry of Economy and Competitiveness of Spain and ERDF (FEDER) (Project DPI2012-37466-C03-03), Fun-c-Food (CSD2007-00063 Consolider-INGENIO 2010), CYTED IBEROFUN (P109AC0302) and Comunidad de Valencia, Project PROMETEO/2010/062. J.G.S. also thanks CSIC and the EU for a predoctoral JAE grant. A.C.S. thanks the Spanish Ministry of Economy and Competitiveness for a Ramon y Cajal contract.Gamboa-Santos, J.; Montilla, A.; Cortijo Soria, A.; Cárcel Carrión, JA.; García Pérez, JV.; Villamiel, M. (2014). Impact of power ultrasound on chemical and physicochemical quality indicators of strawberries dried by convection. Food Chemistry. 161:40-46. https://doi.org/10.1016/j.foodchem.2014.03.106S404616
Does Consumption of Ultra-Processed Foods Matter for Liver Health? Prospective Analysis among Older Adults with Metabolic Syndrome
Non-alcoholic fatty liver disease (NAFLD) includes a spectrum of liver alterations that can result in severe disease and even death. Consumption of ultra-processed foods (UPF) has been associated with obesity and related comorbidities. However, the link between UPF and NAFLD has not been sufficiently assessed. We aimed to investigate the prospective association between UPF consumption and liver health biomarkers. Methods: We followed for 1 year 5867 older participants with overweight/obesity and metabolic syndrome (MetS) from the PREDIMED-Plus trial. A validated 143-item semi-quantitative food frequency questionnaire was used to evaluate consumption of UPF at baseline, 6, and 12 months. The degree of processing for foods and beverages (g/day) was established according to the NOVA classification system. The non-invasive fatty liver index (FLI) and hepatic steatosis index (HSI) were used to evaluate liver health at three points in time. The associations between changes in UPF consumption (percentage of total daily dietary intake (g)) and liver biomarkers were assessed using mixed-effects linear models with repeated measurements. Results: In this cohort, UPF consumption at baseline was 8.19% (SD 6.95%) of total daily dietary intake in grams. In multivariable models, each 10% daily increment in UPF consumption in 1 year was associated with significantly greater FLI (β 1.60 points, 95% CI 1.24;1.96 points) and HSI (0.43, 0.29; 0.57) scores (all p-values < 0.001). These associations persisted statistically significant after adjusting for potential dietary confounders and NAFLD risk factors. Conclusions: A higher UPF consumption was associated with higher levels of NAFLD-related biomarkers in older adults with overweight/obesity and MetS
Efectos de la suplementación con microminerales en indicadores de producción y su residualidad en sangre, heces y orina de alpacas (Lama lama) en pastoreo.
Con el objetivo de analizar el efecto del nivel de suplemento de microminerales adicionales a la dieta sobre las variables alzada peso y diámetro de la fibra de alpacas, se evaluó la aplicación de tres dosis de selenio y zinc (0,0; 1,0 y 1,5 cc), bajo un (DCA) en arreglo factorial (3 x 2) + (3 x 2). Los resultados mostraron diferencias estadísticas para tratamientos: dosis de selenio, edades, dosis de zinc, edades y para la interacción zinc por edades (Se1E2 con 74,33 kg a los 90 días para alzada a la cruz, Zn1E2 con un promedio de 91,33 cm). La longitud de la fibra los tratamientos Se1E1 y Se1E2 con promedio de 3 cm. Para el diámetro de la fibra los tratamientos 1 (Se0E1) y tratamiento Se1E1 del grupo 1 y los tratamientos Zn0E2 y Zn1E1 del grupo 2 mostraron mejor calidad de la fibra (P < 0,05), con promedios de 28 micras. Se confirmó un efecto beneficioso en el peso vivo, calidad de la fibra en animales maduros de la suplementación con los microelementos Se y Zn, que mejoró las características fenotípicas de producción como el peso vivo, aunque manifestó residualidad en la orina de los animales de 3 a 5 años de edad.Effects of Supplementation with Microminerals on Production Indicators and Blood, Feces, and Urine Traces of Grazing alpaca (Lama lama) ABSTRACTIn this area was applied three doses of selenium and zinc (0.0; 1.0 and 1.5 cc), under a (DCA) in factorial arrangement (3 x 2) + (3 x 2) in order to analyze the effect of the level of additional mineral supplement micro (Selenium, Zinc) to the diet on the raised variables, weight and fiber diameter of alpacas. Results revealed statistical differences for treatment: selenium doses, age, Zinc doses, Zinc interaction for ages. For this, the treatment 4 (Se1E2) with 74.33 kg to 90 days to cross height (Zn1E2) with 91.33 cm average. The length fiber into treatments 3 (Se1E1) and 4 (Se1E2) with 3 cm average. For fiber diameter on treatments 1 (Se0E1) Treatment 3 (Se1E1) of group 1, treatments 8 (Zn0E2) and 9 (Zn1E1) which group 2 charged better fiber quality with 28 microns average. It was confirmed an beneficial effect on live weight and fiber quality in mature animals for mineral supply with Se and Zn con los microelements, that improved the production phenotypical characteristics like weight, but it was manifested minerals urine residuality in 3-5 years old animals
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