51 research outputs found

    Effect of alkaline pre-treatment on the anaerobic biodegradability of coffee husk

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    The present paper deals with the mono-digestion of coffee husk during the operation of batch reactors and semi-continuous stirred tank reactor (S-CSTR) using both pre-treated residual at 3% Ca(OH)2 and without pre-treatment. The semi-continuous operation was carried out in 4 stages at different organic loading rate (OLR, [gVS L -1 d -1]) and hydraulic retention time (HRT, [d]) (OLR:HRT) ratios (0.1:90, 0.2:90, 0.2:45 and 0.2:30). As a result of the pre-treatment, up to 223% of the organic matter solubilisation was obtained. However, pre-treatment did not provide better results in biodegradability, observing a negative trend in methane yield when operating in S-CSTR, due to the accumulation of compounds from the fractionation of the lignin as is the case of polyphenols. The operation was further developed using the residual without pre-treatment. The highest methane yield was obtained at 45:0.2 when using the residual without pre-treatment being with 277 mLCH4 gVS-1 , for a methane productivity of 1.1 L L-1 d -1. When implementing the 30:0.2 ratio, a biomass washout was observed in the system, so it is recommended to operate at low OLR and high HRT when treating solid coffee wastes

    Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

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    Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Modelling human choices: MADeM and decision‑making

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    Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)

    Uso de los residuos sólidos mineros de la extracción del níquel como estimulantes para la producción de biogás. // Use of the nickel solid mining residuals as stimulants for the biogasproduction.

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    La adición de diferentes materiales con vistas a mejorar el proceso anaerobio ha venido incrementándose en los últimostiempos existiendo bases teóricas bien fundamentadas para la realización de esta práctica. Este proceso biológico, requiereno sólo de macronutrientes (N, P, K, S), elementos vitales para el desarrollo de los microorganismos y que deben estarpresentes en grandes cantidades, sino también de los denominados micronutrientes y factores estimulantes al proceso, loscuales en cantidades muy pequeñas (trazas), son esenciales para el óptimo desarrollo de los microorganismos, como es elcaso de algunos metales obligatorios (Fe, Ni y Co).En este trabajo se presenta un estudio preliminar del efecto de la adición de residuales mineros cubanos como catalizadoresdel proceso anaerobio. Se realizó la caracterización de dicho residual minero (Cola), empleado en los ensayosexperimentales. Se demostró que la Cola SI aporta nutrientes esenciales al proceso de depuración anaerobia de aguasresiduales. Hubo mayor efectividad en condiciones extremas: poco sustrato y concentraciones tóxicas de Nitrógeno yAzufre, y en cualquiera de las variantes analizadas, la mejor respuesta se obtuvo con una concentración de Cola igual a 3mg/L, con una eliminación de materia orgánica de más del 80%.Palabras claves: Digestión anaerobia, biogás, traza de metales, residuo minero.________________________________________________________________________________Abstract.The addition of several compounds in order to improve anaerobic process has been increased during last decades, beingwell-sustained by theoretical bases. This biological process requires not only macronutrients (N, P, K, S), essentialelements in large quantities for microorganisms well developments, but also those known as micronutrients and stimulatingelements which in a very small concentrations are of vital importance for the optimum microorganism development, as thecase of obligatory metals like Fe, Ni and Co.A preliminary study of mining residues effect on anaerobic process is presented in this paper. Mining residues can be aperfect metal supplier, and indeed act as a biocatalyst. A characterization of the used mining residue (Cola) was made. Itwas demonstrated that Cola did contribute essential nutrients to wastewater anaerobic process. There was bettereffectiveness under extreme conditions: less substrate and toxic concentrations in Nitrogen and Sulphur. In all cases, thebest answer was obtained when Cola concentration was around 3mg/l, with an organic matter removing of more than 80%.Keywords: Anaerobic digestion, biogas, trace metals, mining residues.</p

    Semi-continuous co-digestion of solid cattle slaughterhouse wastes with other waste streams: Interactions within the mixtures and methanogenic community structure

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    The performance of the anaerobic co-digestion process is strongly related to the characteristics of the substrates utilized. In this work, the impact of mixture interactions, i.e., synergy and antagonism, previously observed in batch operation mode were evaluated under semi-continuous co-digestion of slaughterhouse waste (SB) and its different combinations with manure (M), various crops (VC), and municipal solid waste (MSW). The effects on the process performance and the microbial community structure were investigated. The digestion of SB failed at an OLR of 0.9 gVS L-1 d(-1). However, stable performance with higher loadings was observed for mixtures that displayed synergy obtained earlier in the batch mode (i.e., SB + M, SB + VC + MSW). Bacterial and Archaeal groups increased for the SB + M and SB + VC + MSW, compared with the digestion of SB alone and that for SB + VC. The combination that showed antagonistic effects (SB + VC) resulted in unstable operation and poor representation of methanogens. It was proved that synergetic or antagonistic effects observed in batch mode due to the different mixture compositions could be correlated to process performance, as well as the development of the microbial community structure during semi-continuous operation

    Energetic, environmental and economic potentialities of the anaerobic treatment of rice Straw for the case of the Cuban enterprise “Sur del Jíbaro”

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    Rice harvesting and production generates a residual biomass that does not possess an environmentally sustainable disposition route; however, it could be an important carbon source for energetic processes. In this paper the energetic potential via cogeneration that can be obtained from the biogas resulting from the anaerobic treatment of the rice-harvesting wastes (rice straw), for the case of the Cuban Agro-industrial Grain Enterprise “Sur del Jíbaro”, is estimated, based on experimental operation variables and production parameters. Through a life cycle analysis of rice production, an assessment of the environmental profile when this treatment alternative is used in the study case is carried out. The results prove that if the rice straw available in the enterprise is anaerobically treated, it can be profitably obtained a potential to generate 10 MW of electrical power and 15 MW of thermal power via biogas, with a positive environmental contribution to the rice production process. This would decrease the total greenhouse gas emissions in Cuba by 0.2% and the equivalent emissions of the Cuban energetic sector by 3.2%

    Effect of natural mineral on methane production and process stability during semi-continuous mono-digestion of maize atraw

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    The effect of natural mineral on the mono-digestion of maize straw was evaluated in continuously stirred tank reactors (CSTRs) at 38 A degrees C. Different strategies of mineral addition were studied. The organic loading rate (OLR) was varied from 0.5 to 2.5 g volatile solid (VS) L-1 d(-1). A daily addition of 1 g mineral L-1 in reactor 2 (R2) diminished the methane production by about 11 % with respect to the initial phase. However, after a gradual addition of mineral, an average methane yield of 257 NmL CH4 g VS-1 was reached and the methane production was enhanced by 30 % with regard to R1. An increase in the frequency of mineral addition did not enhance the methane production. The archaeal community was more sensitive to the mineral than the bacterial population whose similarity stayed high between R1 and R2. Significant difference in methane yield was found for both reactors throughout the operation.1781522153

    COMBINED TREATMENT OF VINASSE BY AN UPFLOW ANAEROBIC FILTER-REACTOR AND OZONATION PROCESS

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    Abstract - The aim of the present study was to evaluate the efficacy of treating vinasse using anaerobic digestion (AD) followed by ozonation. The AD process was performed using a laboratory-scale upflow anaerobic filter reactor (UAFR) under continuous operation at 29 ± 1 °C. Stable conditions were reached at 10 kgCOD m -3 d -1 and a hydraulic retention time (HRT) of 5 days. Under these conditions, the efficiency of reduction of the chemical oxygen demand (COD) and the methane yield were 75.1% and 0.315 m 3 CH 4 kgCODr -1 , respectively. The anaerobically digested effluent was further treated using ozone in a bubbling column. An experimental 2 3 array [C(0 3 ) g = 70; 100 mgO 3 L -1 ; pH= 7.5; 10; tc = 1 and 3 h] was used. The best conditions for effluent ozonation were 100 mgO 3 L -1 , pH 7.5 and 3 hours of contact with ozone. The average efficiencies for COD, color and turbidity reduction were 82.4, 93.8 and 99.3%, respectively
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