Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 92
Filter
1.
Sci Total Environ ; 915: 169863, 2024 Mar 10.
Article in English | MEDLINE | ID: mdl-38190906

ABSTRACT

Decentralised wastewater treatment is becoming a suitable strategy to reduce cost and environmental impact. In this research, the performance of two technologies treating black water (BW) and grey water (GW) fractions of urban sewage is carried out in a decentralised treatment of the wastewater produced in three office buildings. An Anaerobic Membrane Bioreactor (AnMBR) treating BW and a Hybrid preanoxic Membrane Bioreactor (H-MBR) containing small plastic carrier elements, treating GW were operated at pilot scale. Their potential on reducing the release of contaminants of emerging concern (CECs) such as Organic Micropollutants (OMPs), Antibiotic Resistance Genes (ARGs) and pathogens was studied. After 226 d of operation, a stable operation was achieved in both systems: the AnMBR removed 92.4 ± 2.5 % of influent COD, and H-MBR removed 89.7 ± 3.5 %. Regarding OMPs, the profile of compounds differed between BW and GW, being BW the matrix with more compounds detected at higher concentrations (up to µg L-1). For example, in the case of ibuprofen the concentrations in BW were 23.63 ± 3.97 µg L-1, 3 orders of magnitude higher than those detected in GW. The most abundant ARGs were sulfonamide resistant genes (sul1) and integron class 1 (intl1) in both BW and GW. Pathogenic bacteria counts were reduced between 1 and 3 log units in the AnMBR. Bacterial loads in GW were much lower than in BW, being no bacterial re-growth observed for the GW effluents after treatment in the H-MBR. None of the selected enteric viruses was detected in GW treatment line.


Subject(s)
Anti-Bacterial Agents , Water Purification , Water , Wastewater , Sewage/microbiology , Drug Resistance, Microbial/genetics , Genes, Bacterial , Bioreactors/microbiology , Waste Disposal, Fluid
2.
Med. intensiva (Madr., Ed. impr.) ; 46(5): 248-258, mayo. 2022. ilus, tab, graf
Article in Spanish | IBECS | ID: ibc-204312

ABSTRACT

Objetivo: La pandemia de la COVID-19 ha supuesto una amenaza de colapso de los servicios hospitalarios y de unidades de cuidado intensivo (UCI), así como una reducción de la dinámica asistencial de pacientes afectados por otras patologías. El objetivo fue desarrollar un modelo matemático diseñado para optimizar las predicciones relacionadas con las necesidades de hospitalización e ingresos en UCI por la COVID-19. Diseño: Estudio prospectivo. Ámbito: Provincia de Granada (España). Pacientes: Pacientes de COVID-19 hospitalizados, ingresados en UCI, recuperados y fallecidos desde el 15 de marzo hasta el 22 de septiembre del 2020. Intervenciones: Desarrollo de un modelo matemático tipo susceptible, expuesto, infectado y recuperado (SEIR) capaz de predecir la evolución de la pandemia, considerando las medidas de salud pública establecidas. Variables de interés: Número de pacientes infectados por SARS-CoV-2, hospitalizados e ingresados en UCI por la COVID-19.Resultados: A partir de los datos registrados, hemos podido desarrollar un modelo matemático que refleja el flujo de la población entre los diferentes grupos de interés en relación con la COVID-19. Esta herramienta permite analizar diferentes escenarios basados en medidas de restricción socio-sanitarias y pronosticar el número de infectados, hospitalizados e ingresados en UCI. Conclusiones: El modelo matemático es capaz de proporcionar predicciones sobre la evolución de la COVID-19 con suficiente antelación como para poder conjugar los picos de prevalencia y de necesidades de asistencia hospitalaria y de UCI, con la aparición de ventanas temporales que posibiliten la atención de enfermos no-COVID (AU)


Objective: The COVID-19 pandemic has threatened to collapse hospital and ICU services, and it has affected the care programs for non-COVID patients. The objective was to develop a mathematical model designed to optimize predictions related to the need for hospitalization and ICU admission by COVID-19 patients. Design: Prospective study. Setting: Province of Granada (Spain). Population: COVID-19 patients hospitalized, admitted to ICU, recovered and died from March 15 to September 22, 2020. Study variables: The number of patients infected with SARS-CoV-2 and hospitalized or admitted to ICU for COVID-19. Results: The data reported by hospitals was used to develop a mathematical model that reflects the flow of the population among the different interest groups in relation to COVID-19. This tool allows to analyse different scenarios based on socio-health restriction measures, and to forecast the number of people infected, hospitalized and admitted to the ICU. Conclusions:The mathematical model is capable of providing predictions on the evolution of the COVID-19 sufficiently in advance as to anticipate the peaks of prevalence and hospital and ICU care demands, and also the appearance of periods in which the care for non-COVID patients could be intensified (AU)


Subject(s)
Humans , Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , Pandemics , Models, Theoretical , Intensive Care Units , Prospective Studies
3.
Med Intensiva (Engl Ed) ; 46(5): 248-258, 2022 05.
Article in English | MEDLINE | ID: mdl-35256322

ABSTRACT

OBJECTIVE: The COVID-19 pandemic has threatened to collapse hospital and ICU services, and it has affected the care programs for non-COVID patients. The objective was to develop a mathematical model designed to optimize predictions related to the need for hospitalization and ICU admission by COVID-19 patients. DESIGN: Prospective study. SETTING: Province of Granada (Spain). POPULATION: COVID-19 patients hospitalized, admitted to ICU, recovered and died from March 15 to September 22, 2020. STUDY VARIABLES: The number of patients infected with SARS-CoV-2 and hospitalized or admitted to ICU for COVID-19. RESULTS: The data reported by hospitals was used to develop a mathematical model that reflects the flow of the population among the different interest groups in relation to COVID-19. This tool allows to analyse different scenarios based on socio-health restriction measures, and to forecast the number of people infected, hospitalized and admitted to the ICU. CONCLUSIONS: The mathematical model is capable of providing predictions on the evolution of the COVID-19 sufficiently in advance as to anticipate the peaks of prevalence and hospital and ICU care demands, and also the appearance of periods in which the care for non-COVID patients could be intensified.


Subject(s)
COVID-19 , COVID-19/epidemiology , Delivery of Health Care , Humans , Intensive Care Units , Models, Theoretical , Pandemics , Prospective Studies , SARS-CoV-2
4.
Article in English, Spanish | MEDLINE | ID: mdl-33926752

ABSTRACT

OBJECTIVE: The COVID-19 pandemic has threatened to collapse hospital and ICU services, and it has affected the care programs for non-COVID patients. The objective was to develop a mathematical model designed to optimize predictions related to the need for hospitalization and ICU admission by COVID-19 patients. DESIGN: Prospective study. SETTING: Province of Granada (Spain). POPULATION: COVID-19 patients hospitalized, admitted to ICU, recovered and died from March 15 to September 22, 2020. STUDY VARIABLES: The number of patients infected with SARS-CoV-2 and hospitalized or admitted to ICU for COVID-19. RESULTS: The data reported by hospitals was used to develop a mathematical model that reflects the flow of the population among the different interest groups in relation to COVID-19. This tool allows to analyse different scenarios based on socio-health restriction measures, and to forecast the number of people infected, hospitalized and admitted to the ICU. CONCLUSIONS: The mathematical model is capable of providing predictions on the evolution of the COVID-19 sufficiently in advance as to anticipate the peaks of prevalence and hospital and ICU care demands, and also the appearance of periods in which the care for non-COVID patients could be intensified.

5.
Vaccine ; 39(11): 1631-1641, 2021 03 12.
Article in English | MEDLINE | ID: mdl-33597115

ABSTRACT

Records of cattle vaccination against paratuberculosis (PTB) have been analyzed to determine whether or not non-specific effect (NSE) on overall mortality similar to that observed in BCG vaccinated humans occurs in animals. The results of a previously reported slaughterhouse study on PTB prevalence were used as a reference on the age incidence of advanced patent (clinical) epidemio-pathogenic forms. In the proper vaccine study, cows in 30 cattle farms in the Basque Country, Spain were followed-up for between 1 and 13 years. Vaccinated groups were composed by 1008 (592 right-censored) animals younger than 3 months treated as calves and by 3761 (3160 right-censored) vaccinated at any older age. Controls were 339 (157 right-censored) and 4592 (2213 right-censored) age matched animals, respectively. Individual last year presence in the annual testing was considered age at culling or death. A survival analysis was carried out according age at vaccination of vaccinated versus non-vaccinated animals. PTB age incidence in the slaughterhouse study was subtracted from the difference between vaccinated and non-vaccinated animals at the same age in order to estimate PTB-specific and non-specific effects. The maximum difference was observed at the 2-3 years interval with a 33.9% mortality reduction in the calf vaccinated group. This corresponded also with the maximum NSE that was 24.5% for a PTB incidence of 9.5%. Overall, vaccination afforded to calves a 26.5% yearly mortality protection, split between 11.1% PTB-specific and 15.4% NSE. These results support a NSE on total mortality associated with PTB vaccination that appeared to persist for up to 6-7 years. This confirms for the first time in an animal field study the innate immune system memory predicted by the recently proposed trained immunity theory. Contrasting the literature, no deleterious effects of killed vaccines on females were observed. Mortality reduction would offset vaccination costs and could improve livestock systems efficiency and potentially reduce antibiotic use. Clinical trial registered with Spanish Agency for Drugs and Sanitary products (AEMPS) as 11/012/ECV.


Subject(s)
Cattle Diseases , Mycobacterium avium subsp. paratuberculosis , Paratuberculosis , Animals , Cattle , Female , Longevity , Paratuberculosis/epidemiology , Paratuberculosis/prevention & control , Spain/epidemiology , Vaccination
6.
J Environ Manage ; 263: 110395, 2020 Jun 01.
Article in English | MEDLINE | ID: mdl-32883477

ABSTRACT

One of the main drawbacks of upflow anaerobic sludge blanket (UASB) reactors that treat low-strength sewage at room temperature is related to the low quality of their effluents in terms of dissolved methane, organic matter, and nitrogen content. The present study aims to evaluate the feasibility of using an integrated fixed-film activated sludge (IFAS) system as an alternative post-treatment technology to mitigate the environmental impact of such effluents. For this purpose, a pilot plant composed of a UASB (120 L) followed by an IFAS (66 L) system was operated for 407 days. Special attention was paid to the suspended biomass retention capacity and the dissolved methane and nitrogen removal potential of the IFAS post-treatment system. Furthermore, the role of carriers on denitrification and nitrification processes and the microbial communities present in the biofilm were also analyzed. Average total chemical oxygen demand (CODT) and ammonium removal efficiencies of 92 ± 3% and around 57 ± 16% were attained throughout the entire operation, respectively. During a first period in which biomass was maintained in both biofilms and suspension, and nitrite was the main electron acceptor, maximum nitrogen removal and methane removal efficiencies of 32.5 mg TN L-1 and 93% were observed in the IFAS system, respectively. However, throughout the second period, in which suspended biomass was completely washed out from the IFAS system, and nitrate became the main electron acceptor, these values decreased to 18 ± 4 mg TN Lfeed-1 and 77 ± 12%, respectively. Surprisingly, throughout the entire operation, it was observed that around 50 and 41% of the total nitrogen and methane removals observed in the IFAS system, respectively, were carried out in the aerobic compartment. Aerobic methane oxidizers and anammox were detected with significant relative abundances in the biofilm carriers used in the anoxic and aerobic compartments using 16S rRNA gene amplicon sequencing analysis. Therefore, the use of an IFAS system could be suited to diminish greenhouse gas emissions and nutrients concentration for those sewage treatment plants that used UASB systems, especially in countries with temperate and warm climates.


Subject(s)
Nitrogen , Sewage , Anaerobiosis , Bioreactors , Methane , RNA, Ribosomal, 16S , Waste Disposal, Fluid
7.
Sci Total Environ ; 671: 165-174, 2019 Jun 25.
Article in English | MEDLINE | ID: mdl-30928746

ABSTRACT

The use of a hybrid membrane bioreactor (MBR) post-treatment system is proposed as a cost-efficient technology in order to minimize the environmental impact of anaerobic effluents, treating low-strength sewage at room temperature, such as their high nitrogen content and the presence of dissolved methane. In this research, nitrite was externally added at different concentrations into the anoxic compartment, providing an extra electron acceptor besides the existing nitrate, to evaluate its effect on denitrification, methane oxidation and OMPs removal processes. The nitrite addition significantly improved the denitrification potential of the system, achieving nitrogen removals up to 35 mg TN L-1. Moreover, higher nitrite concentrations clearly promoted an increase in the removal of some organic micropollutants (OMPs) such as diclofenac (DCF), ethinylestradiol (EE2), triclosan (TCS) and ibuprofen (IBP). Nevertheless, methane removal efficiencies or rates were not affected by this fact. Finally, COD and ammonium removals higher than 99 and 91% were observed during the entire operation, respectively. Based on the results, a future strategy in which ammonium is partially oxidized to nitrite could result in better nitrogen and OMPs removals for the proposed technology.

8.
Vet J ; 244: 98-103, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30825903

ABSTRACT

Red deer (Cervus elaphus) farming is a growing economic activity worldwide. However, the capacity of this species to act as reservoir of animal tuberculosis (TB) poses a threat to other wildlife and to livestock. Diagnostic assay accuracy in this species is therefore highly relevant for prevention and control measures. Our aim was to evaluate the diagnostic performance of the protein complex P22, obtained from Mycobacterium bovis derived purified protein derivative (bPPD), as a candidate antigen for the detection of antibodies against Mycobacterium tuberculosis complex (MTC). We assessed the performance of this new antigen in indirect enzyme-linked immunosorbent assays (ELISA) in TB-positive and TB-negative red deer, in comparison with a bPPD-based ELISA. The P22 ELISA achieved a higher specificity (Sp) and similar sensitivity (Se) in comparison with the bPPD ELISA at all the cut-off points considered. The P22 ELISA yielded optimal Sp (99.02%; 95% confidence intervals [CI95%]: 96.5-99.8) and appropriate Se (70.1%; CI95%: 63.6-76) at the selected cut-off point of 100%. These results suggest that P22 can be used as an alternative antigen in the immunodiagnosis of animal TB through the use of an ELISA-type detection of antibodies against MTC in red deer, thus contributing to the diagnosis of animal TB in this species as a measure for further disease prevention and control programs.


Subject(s)
Antibodies, Bacterial/blood , Deer , Mycobacterium tuberculosis/immunology , Tuberculosis, Pulmonary/veterinary , Animals , Disease Reservoirs , Enzyme-Linked Immunosorbent Assay/veterinary , Female , Male , Mycobacterium tuberculosis/isolation & purification , Predictive Value of Tests , Tuberculin Test/veterinary , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/microbiology
9.
J Hazard Mater ; 359: 113-120, 2018 10 05.
Article in English | MEDLINE | ID: mdl-30014906

ABSTRACT

An innovative process based on the combination of a UASB reactor and an IFAS system is proposed in order to combine different redox conditions and biomass conformations to promote a high microbial diversity. The objective of this configuration is to enhance the biological removal of organic micropollutants (OMPs) as well as to achieve the abatement of nitrogen by using the dissolved methane as an inexpensive electron donor. Results showed high removals of COD (93%) and dissolved methane present in the UASB effluent (up to 85%) was biodegraded by a consortium of aerobic methanotrophs and heterotrophic denitrifiers. Total nitrogen removal decreased slightly along the operation (from 44 to 33%), depending on the availability of electron donor, biomass concentration, and configuration (floccules and biofilm). A high removal was achieved in the hybrid system (>80%) for 6 of the studied OMPs. Sulfamethoxazole, trimethoprim, naproxen, and estradiol were readily biotransformed under anaerobic conditions, whereas ibuprofen or bisphenol A were removed in the anoxic-aerobic compartment. Evidence of the cometabolic biotransformation of OMPs has been found, such as the influence of nitrification activity on the removal of bisphenol A, and of the denitrification activity on ethinylestradiol removal.


Subject(s)
Bioreactors , Waste Disposal, Fluid/methods , Aerobiosis , Anaerobiosis , Cost-Benefit Analysis , Methane/metabolism , Nitrogen/metabolism , Oxidation-Reduction , Sewage , Water Pollutants, Chemical/metabolism
10.
Water Res ; 118: 272-288, 2017 07 01.
Article in English | MEDLINE | ID: mdl-28456110

ABSTRACT

The growing development of technologies and processes for resource treatment and recovery is offering endless possibilities for creating new plant-wide configurations or modifying existing ones. However, the configurations' complexity, the interrelation between technologies and the influent characteristics turn decision-making into a complex or unobvious process. In this frame, the Plant-Wide Modelling (PWM) library presented in this paper allows a thorough, comprehensive and refined analysis of different plant configurations that are basic aspects in decision-making from an energy and resource recovery perspective. In order to demonstrate the potential of the library and the need to run simulation analyses, this paper carries out a comparative analysis of WWTPs, from a techno-economic point of view. The selected layouts were (1) a conventional WWTP based on a modified version of the Benchmark Simulation Model No. 2, (2) an upgraded or retrofitted WWTP, and (3) a new Wastewater Resource Recovery Facilities (WRRF) concept denominated as C/N/P decoupling WWTP. The study was based on a preliminary analysis of the organic matter and nutrient energy use and recovery options, a comprehensive mass and energy flux distribution analysis in each configuration in order to compare and identify areas for improvement, and a cost analysis of each plant for different influent COD/TN/TP ratios. Analysing the plants from a standpoint of resources and energy utilization, a low utilization of the energy content of the components could be observed in all configurations. In the conventional plant, the COD used to produce biogas was around 29%, the upgraded plant was around 36%, and 34% in the C/N/P decoupling WWTP. With regard to the self-sufficiency of plants, achieving self-sufficiency was not possible in the conventional plant, in the upgraded plant it depended on the influent C/N ratio, and in the C/N/P decoupling WWTP layout self-sufficiency was feasible for almost all influents, especially at high COD concentrations. The plant layouts proposed in this paper are just a sample of the possibilities offered by current technologies. Even so, the library presented here is generic and can be used to construct any other plant layout, provided that a model is available.


Subject(s)
Wastewater , Water Purification/instrumentation , Sewage , Waste Disposal, Fluid
11.
Water Sci Technol ; 75(3-4): 609-618, 2017 02.
Article in English | MEDLINE | ID: mdl-28192355

ABSTRACT

A full-scale struvite crystallization system was operated for the treatment of the centrate obtained from the sludge anaerobic digester in a municipal wastewater treatment plant. Additionally, the feasibility of an industrial grade Mg(OH)2 as a cheap magnesium and alkali source was also investigated. The struvite crystallization plant was operated for two different periods: period I, in which an influent with low phosphate concentration (34.0 mg P·L-1) was fed to the crystallization plant; and period II, in which an influent with higher phosphate concentration (68.0 mg P·L-1) was used. A high efficiency of phosphorus recovery by struvite crystallization was obtained, even when the effluent treated had a high level of alkalinity. Phosphorus recovery percentage was around 77%, with a phosphate concentration in the effluent between 10.0 and 30.0 mg P·L-1. The experiments gained struvite pellets of 0.5-5.0 mm size. Moreover, the consumption of Mg(OH)2 was estimated at 1.5 mol Mg added·mol P recovered-1. Thus, industrial grade Mg(OH)2 can be an economical alternative as magnesium and alkali sources for struvite crystallization at industrial scale.


Subject(s)
Magnesium Hydroxide/chemistry , Phosphates/analysis , Struvite/chemistry , Wastewater/chemistry , Water Pollutants/analysis , Water Purification/methods , Crystallization , Feasibility Studies , Phosphates/chemistry , Sewage/chemistry , Water Pollutants/chemistry
12.
Rev Clin Esp (Barc) ; 217(3): 127-135, 2017 Apr.
Article in English, Spanish | MEDLINE | ID: mdl-27912902

ABSTRACT

OBJECTIVE: To analyse the changes in epidemiology, outpatient and emergency department clinical care, and outcomes of patients treated for acute heart failure (AHF) in Spanish hospital emergency departments (HEDs) between 2007 and 2014. METHOD: A multicentre cohort study was conducted that consecutively included patients with AHF diagnosed in 9HEDs during 4 periods (2007, 2009, 2011 and 2014). The study analysed the changes observed in 20 variables corresponding to baseline data, outpatient care and emergency care data and outcome data. RESULTS: A total of 4,845 patients were included. There were significant changes in 13 variables: there was an increase in patients older than 80years (2007/2014: 45.9%/55.4%; P<.001) and a decrease in severe functional dependence (28.2%/19.7%; P<.001). In terms of long-term outpatient care, there was an increased use of beta-blockers (44.6%/57.8%; P=.002) and aldosterone antagonists (26.6%/37.7%; P<.05) among patients with reduced ejection fraction and an increase use of echocardiography (42.8%/56.2%; P=.001). The use of digoxin decreased (25.4%/16.9%; P=.005). In terms of emergency care, there was an increase in requests for troponins (54.6%/61.9%; P<.001), natriuretic peptides (7.8%/48.5%; P<.001) and the use of noninvasive ventilation (3.2%/6.9%; P=.004). Requests for endovenous perfusion drugs decreased (diuretics: 21.3%/10.4%; P<.001; nitrates: 21.3%/17.5%; P=.001; vasopressors: 4.2%/1.5%; P<.001). Finally, discharges directly from the emergency department without hospitalization increased (20.0%/25.9%; P<.001), and emergency department readmissions at 30days decreased (27.3%/17.6%; P=.007). Hospital mortality and mortality at 30days did not change. CONCLUSIONS: Changes in outcomes were detected during a 7-year period in patients with AHF treated in HEDs, with care that was more in line with the clinical guidelines. There are, however, areas for improvement. There was a noteworthy increase in outpatient follow-up without hospitalisation and a reduction in HED readmissions.

13.
Transbound Emerg Dis ; 64(5): e18-e21, 2017 Oct.
Article in English | MEDLINE | ID: mdl-27292118

ABSTRACT

In 2012, a wild boar (Sus scrofa) tuberculosis (TB) control programme was set up in a wild boar farm by means of intramuscular (IM) vaccination with a heat-inactivated Mycobacterium bovis vaccine (IV). The goal was to assess safety and efficacy of the parenterally administered IV in a large farm setting with natural M. bovis circulation. Based on preceding results under laboratory conditions, we hypothesized that vaccinated piglets would show smaller scores of TB-compatible lesions (TBCL) than unvaccinated controls. After vaccination, no adverse reactions were detected by visual inspection or at post-mortem examination (n = 668 and 97, respectively). Post-mortem data on TBCL were available for 97 vaccinated wild boar and 182 controls. The observed TBCL prevalence was 4.1% (95% CI = 0.2-8%) and 12.1% (95% CI = 7.1-17.1%) for vaccinated and control wild boar, respectively (P < 0.05). Among those animals with TBCL, no difference in the mean lesion score was found (P > 0.05). The results show that IV administered intramuscularly to wild boar piglets is safe and protects vaccinated individuals (66% reduction in TBCL prevalence) against natural challenge in a low-prevalence setting. In a context of increasing TB prevalence in wild boar in Mediterranean habitats, vaccination achieved a progressive though slow decline in lesion prevalence since the onset of the vaccination scheme. Hence, vaccination might contribute, along with other tools, to TB control in wild boar and in pigs.


Subject(s)
Bacterial Vaccines/immunology , Mycobacterium bovis/immunology , Sus scrofa/microbiology , Swine Diseases/prevention & control , Tuberculosis/prevention & control , Vaccination/veterinary , Animals , Autopsy/veterinary , Farms , Female , Injections, Intramuscular/veterinary , Male , Prevalence , Swine , Swine Diseases/epidemiology , Swine Diseases/microbiology , Tuberculosis/epidemiology , Tuberculosis/microbiology , Vaccines, Inactivated/immunology
15.
J Chem Phys ; 144(14): 144702, 2016 Apr 14.
Article in English | MEDLINE | ID: mdl-27083740

ABSTRACT

We have determined the interfacial properties of tetrahydrofuran (THF) from direct simulation of the vapor-liquid interface. The molecules are modeled using six different molecular models, three of them based on the united-atom approach and the other three based on a coarse-grained (CG) approach. In the first case, THF is modeled using the transferable parameters potential functions approach proposed by Chandrasekhar and Jorgensen [J. Chem. Phys. 77, 5073 (1982)] and a new parametrization of the TraPPE force fields for cyclic alkanes and ethers [S. J. Keasler et al., J. Phys. Chem. B 115, 11234 (2012)]. In both cases, dispersive and coulombic intermolecular interactions are explicitly taken into account. In the second case, THF is modeled as a single sphere, a diatomic molecule, and a ring formed from three Mie monomers according to the SAFT-γ Mie top-down approach [V. Papaioannou et al., J. Chem. Phys. 140, 054107 (2014)]. Simulations were performed in the molecular dynamics canonical ensemble and the vapor-liquid surface tension is evaluated from the normal and tangential components of the pressure tensor along the simulation box. In addition to the surface tension, we have also obtained density profiles, coexistence densities, critical temperature, density, and pressure, and interfacial thickness as functions of temperature, paying special attention to the comparison between the estimations obtained from different models and literature experimental data. The simulation results obtained from the three CG models as described by the SAFT-γ Mie approach are able to predict accurately the vapor-liquid phase envelope of THF, in excellent agreement with estimations obtained from TraPPE model and experimental data in the whole range of coexistence. However, Chandrasekhar and Jorgensen model presents significant deviations from experimental results. We also compare the predictions for surface tension as obtained from simulation results for all the models with experimental data. The three CG models predict reasonably well (but only qualitatively) the surface tension of THF, as a function of temperature, from the triple point to the critical temperature. On the other hand, only the TraPPE united-atoms models are able to predict accurately the experimental surface tension of the system in the whole temperature range.

16.
Chemosphere ; 154: 567-572, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27085317

ABSTRACT

The crystallisation of struvite could be a sustainable and economical alternative for recovering phosphorus from wastewater streams with high phosphate concentrations. Knowledge regarding the kinetics and thermodynamics that are involved in the crystallisation of struvite is the key to determine the optimal conditions for obtaining an efficient process. This study was conducted in a continuous stirred batch reactor. Different sets of experiments were performed in which struvite was either dissolved (undersaturated) or precipitated (oversaturated). These experiments were conducted at different temperatures (25, 30 and 35 °C) and pH values (8.2, 8.5 and 8.8) to determine the kinetics of struvite precipitation and dissolution. Struvite crystallisation was modelled as a reversible reaction. The kinetic rate parameters of struvite precipitation were 1.03·10(-4), 1.25·10(-4) and 1.54·10(-4) mol m(-2) min(-1) at 25, 30 and 35 °C, respectively. Similar kinetic rate parameters were determined for struvite dissolution. Struvite heterogeneous crystallisation can be represented by a first-order kinetic model that fitted well the experimental data.


Subject(s)
Phosphates/isolation & purification , Struvite/chemistry , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Crystallization , Kinetics , Thermodynamics , Waste Disposal, Fluid/instrumentation , Water Purification/instrumentation
17.
Environ Sci Pollut Res Int ; 22(6): 4491-9, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25315934

ABSTRACT

The development and application of a polyaniline/carbon nanotube (CNT) cyclodextrin matrix (PANI-ß-CD/MWCNT)-based electrochemical sensor for the quantitative determination of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) and its main transformation product 4-chloro-2-methylphenol in natural waters are described. A simple cyclic voltammetry-based electrochemical methodology, in phosphate buffer solution at pH 6.0, was used to develop a method to determine both MCPA and 4-chloro-2-methylphenol, without any previous extraction or derivatization steps. A linear concentration range (10 to 50 µmol L(-1)) and detection limits of 1.1 and 1.9 µmol L(-1), respectively, were achieved using optimized cyclic voltammetric parameters. The proposed method was successfully applied to the determination of MCPA and 4-chloro-2-methylphenol in natural water samples with satisfactory recoveries (94 to 107%) and in good agreement with the results obtained by an established high-performance liquid chromatography technique, no significant differences being found between the methods. Interferences from ionic species and other herbicides used for broad-leaf weed control were shown to be small. The newly developed methodology was also successfully applied to MCPA photodegradation environmental studies.


Subject(s)
2-Methyl-4-chlorophenoxyacetic Acid/analysis , Cresols/analysis , Environmental Monitoring/methods , Herbicides/analysis , Water Pollutants, Chemical/analysis , 2-Methyl-4-chlorophenoxyacetic Acid/chemistry , Aniline Compounds , Chromatography, High Pressure Liquid , Cresols/chemistry , Cyclodextrins , Electrochemical Techniques , Electrodes , Hydrogen-Ion Concentration , Molecular Structure , Nanotubes, Carbon/analysis , Photolysis
18.
Sci Total Environ ; 490: 871-9, 2014 Aug 15.
Article in English | MEDLINE | ID: mdl-24908646

ABSTRACT

The supernatant resulting from the anaerobic digestion of sludge generated by wastewater treatment plants (WWTP) is an attractive flow for technologies such as partial nitritation-anammox (CANON), nitrite shortcut (NSC) and struvite crystallization processes (SCP). The high concentration of N and P and its low flow rate facilitate the removal of nutrients under more favorable conditions than in the main water line. Despite their operational and economic benefits, the environmental burdens of these technologies also need to be assessed to prove their feasibility under a more holistic perspective. The potential environmental implications of these technologies were assessed using life cycle assessment, first at pilot plant scale, later integrating them in a modeled full WWTP. Pilot plant results reported a much lower environmental impact for N removal technologies than SCP. Full-scale modeling, however, highlighted that the differences between technologies were not relevant once they are integrated in a WWTP. The impacts associated with the WWTP are slightly reduced in all categories except for eutrophication, where a substantial reduction was achieved using NSC, SCP, and especially when CANON and SCP were combined. This study emphasizes the need for assessing wastewater treatment technologies as part of a WWTP rather than as individual processes and the utility of modeling tools for doing so.


Subject(s)
Nitrogen/metabolism , Phosphorus/metabolism , Waste Disposal, Fluid/methods , Wastewater/chemistry , Anaerobiosis , Bioreactors/microbiology , Environmental Monitoring , Nitrogen/analysis , Phosphorus/analysis , Wastewater/microbiology
19.
Rev. calid. asist ; 28(6): 355-360, nov.-dic. 2013. tab
Article in Spanish | IBECS | ID: ibc-117182

ABSTRACT

Objetivo. La insuficiencia cardíaca es una de las principales enfermedades crónicas que afectan a la calidad de vida relacionada con la salud. El objetivo del presente estudio ha sido evaluar la calidad de vida en pacientes con clase funcional i - iii de la New York Heart Association mediante el cuestionario SF-36 usando una cohorte de supervivientes del Grupo de Estudio EPICOUR y compararlo con la calidad de vida de la población general española para el mismo sexo y grupo de edad. Material y métodos. Se diseñó un estudio de cohorte, observacional y prospectivo con los supervivientes del Grupo de Estudio EPICOUR a los que se les realizó control clínico-evolutivo y cuestionario SF-36. Resultados. Se estudió la calidad de vida en 50 pacientes (60% hombres). La edad media de los hombres fue de 64,8 años y de las mujeres de 68,3. Al analizar el SF-36 se observó que los resultados fueron más bajos en la esfera física que en la esfera mental. La calidad de vida empeoraba a medida que aumentaba la clase funcional. Al comparar los pacientes con la población general para el mismo sexo y edad, los pacientes con insuficiencia cardíaca mostraron puntuación inferior en todas las escalas (diferencias significativas en función física, dolor corporal, vitalidad y función social para los hombres y función física y rol emocional para las mujeres). Conclusiones. La insuficiencia cardíaca provoca un impacto negativo en la calidad de vida, tanto en la función física como en la función psicosocial, agravándose el deterioro con el incremento de la clase funcional(AU)


Objective: Heart failure is one of the major chronic diseases that affect health related quality of life. The objective of this study was to evaluate the quality of life in patients with New York Heart Association functional class i-iii using the SF-36 on a cohort of survivors of the EPICOUR Study Group and compare the quality of life with the general Spanish population of the same sex and age group. Material and methods: A cohort study, observational, and prospective study was conducted on survivors of the EPICOUR Study Group, on whom a clinical-progression-outcome review was performed along with the SF-36. Results: The quality of life was studied in 50 patients (60% male). The average age of men was 64.8 years and women 68.3. When analyzing the SF-36, it was observed that the results were lower in the physical dimensions than in the mental dimensions. The quality of life worsened with increasing functional class (statistically significant differences for scales of physical functioning, social functioning and borderline significance in mental health scale). When comparing patients with the general population of the same age and sex, patients with heart failure showed lower scores on all scales (significant differences in physical functioning, body pain, vitality, and social role for men, and physical function and emotional role for women). Conclusions: Heart failure causes a negative impact on quality of life, physical functioning, as well as psychosocial function, with the impairment becoming worse with increased functional class (AU)


Subject(s)
Humans , Male , Female , Middle Aged , Quality of Life/legislation & jurisprudence , Heart Failure/epidemiology , Heart Failure/prevention & control , Quality of Life , Heart Valve Diseases/epidemiology , Heart Valve Diseases/prevention & control , Surveys and Questionnaires/standards , Surveys and Questionnaires , Cohort Studies , Prospective Studies
20.
Rev Calid Asist ; 28(6): 355-60, 2013.
Article in Spanish | MEDLINE | ID: mdl-24112870

ABSTRACT

OBJECTIVE: Heart failure is one of the major chronic diseases that affect health related quality of life. The objective of this study was to evaluate the quality of life in patients with New York Heart Association functional class I-III using the SF-36 on a cohort of survivors of the EPICOUR Study Group and compare the quality of life with the general Spanish population of the same sex and age group. MATERIAL AND METHODS: A cohort study, observational, and prospective study was conducted on survivors of the EPICOUR Study Group, on whom a clinical-progression-outcome review was performed along with the SF-36. RESULTS: The quality of life was studied in 50 patients (60% male). The average age of men was 64.8 years and women 68.3. When analyzing the SF-36, it was observed that the results were lower in the physical dimensions than in the mental dimensions. The quality of life worsened with increasing functional class (statistically significant differences for scales of physical functioning, social functioning and borderline significance in mental health scale). When comparing patients with the general population of the same age and sex, patients with heart failure showed lower scores on all scales (significant differences in physical functioning, body pain, vitality, and social role for men, and physical function and emotional role for women). CONCLUSIONS: Heart failure causes a negative impact on quality of life, physical functioning, as well as psychosocial function, with the impairment becoming worse with increased functional class.


Subject(s)
Heart Failure , Quality of Life , Surveys and Questionnaires , Aged , Cohort Studies , Cross-Sectional Studies , Female , Heart Failure/diagnosis , Humans , Male , Middle Aged , Prospective Studies
SELECTION OF CITATIONS
SEARCH DETAIL
...