RESUMO
The objective of this study was to determine the optimal inclusion level of liquid egg hatchery waste for the anaerobic co-digestion of dairy cattle manure. A completely randomized experimental was applied, with seven treatments (liquid hatchery waste to cattle manure ratios of 0: 100, 5:95, 10:90, 15:85, 20:80, 25:75 and 30:70), with five replicates (batch digester model) each. The evaluated variables were disappearance of total solids (TS), volatile solids (VS), and neutral detergent fiber (NDF), and specific production of biogas and of methane. Maximum TS and VS disappearance of 41.3% and 49.6%, were obtained at 15.5% and 16.0% liquid hatchery waste inclusion levels. The addition of 22.3% liquid hatchery considerably reduced NDF substrate content (53.2%). Maximum specific biogas production was obtained with 17% liquid hatchery waste, with the addition of 181.7 and 229.5 L kg-1TS and VS, respectively. The highest methane production, at 120.1 and 151.8 L CH4 kg-1TS and VS, was obtained with the inclusion of 17.5 and 18.0% liquid hatchery waste, respectively. The addition of liquid hatchery waste atratios of up to 15.5%in co-digestion with cattle manure reduced solid and fiber levels in the effluent, and improved biogas and methane production.(AU)
Assuntos
Animais , Digestão Anaeróbia/análise , Produtos Avícolas/análise , Resíduos , Sólidos Totais/análise , Sólidos Voláteis/análise , Biocombustíveis/análise , Metano/análiseRESUMO
The objective of this study was to determine the optimal inclusion level of liquid egg hatchery waste for the anaerobic co-digestion of dairy cattle manure. A completely randomized experimental was applied, with seven treatments (liquid hatchery waste to cattle manure ratios of 0: 100, 5:95, 10:90, 15:85, 20:80, 25:75 and 30:70), with five replicates (batch digester model) each. The evaluated variables were disappearance of total solids (TS), volatile solids (VS), and neutral detergent fiber (NDF), and specific production of biogas and of methane. Maximum TS and VS disappearance of 41.3% and 49.6%, were obtained at 15.5% and 16.0% liquid hatchery waste inclusion levels. The addition of 22.3% liquid hatchery considerably reduced NDF substrate content (53.2%). Maximum specific biogas production was obtained with 17% liquid hatchery waste, with the addition of 181.7 and 229.5 L kg-1TS and VS, respectively. The highest methane production, at 120.1 and 151.8 L CH4 kg-1TS and VS, was obtained with the inclusion of 17.5 and 18.0% liquid hatchery waste, respectively. The addition of liquid hatchery waste atratios of up to 15.5%in co-digestion with cattle manure reduced solid and fiber levels in the effluent, and improved biogas and methane production.
Assuntos
Animais , Digestão Anaeróbia/análise , Produtos Avícolas/análise , Resíduos , Biocombustíveis/análise , Metano/análise , Sólidos Totais/análise , Sólidos Voláteis/análiseRESUMO
Valencia orange (Citrus sinensis) peel was employed in this work as raw material for the production of citric acid (CA) by solid-state fermentation (SSF) of Aspergillus niger CECT-2090 (ATCC 9142, NRRL 599) in Erlenmeyer flasks. To investigate the effects of the main operating variables, the inoculum concentration was varied in the range 0.5À10³ to 0.7À10(8) spores/g dry orange peel, the bed loading from 1.0 to 4.8 g of dry orange peel (corresponding to 35-80 percent of the total volume), and the moisture content between 50 and 100 percent of the maximum water retention capacity (MWRC) of the material. Moreover, additional experiments were done adding methanol or water in different proportions and ways. The optimal conditions for CA production revealed to be an inoculum of 0.5À10(6) spores/g dry orange peel, a bed loading of 1.0 g of dry orange peel, and a humidification pattern of 70 percent MWRC at the beginning of the incubation with posterior addition of 0.12 mL H2O/g dry orange peel (corresponding to 3.3 percent of the MWRC) every 12 h starting from 62 h. The addition of methanol was detrimental for the CA production. Under these conditions, the SSF ensured an effective specific production of CA (193 mg CA/g dry orange peel), corresponding to yields of product on total initial and consumed sugars (glucose, fructose and sucrose) of 376 and 383 mg CA/g, respectively. These results, which demonstrate the viability of the CA production by SSF from orange peel without addition of other nutrients, could be of interest to possible, future industrial applications.
Assuntos
Ácido Cítrico/análise , Aspergillus niger/isolamento & purificação , Citrus , Citrus sinensis , Fermentação , Metanol/análise , Pectinas , Sólidos Voláteis , Amostras de Alimentos , Métodos , Bebidas Gaseificadas , MétodosRESUMO
Esta investigación tuvo como objetivo determinar las concentraciones de solventes volátiles en el Laboratorio de Ingeniería Química (LIQ) de la Universidad de Carabobo, ValenciaVenezuela. Los equipos evaluados fueron las torres de destilación y extracción sólido-líquido; operando con etanol-agua y hexano como solventes extractivos respectivamente. Se empleó un muestreador activo para recolectar la muestra gaseosa y un medio de colección físico y químico, carbón activado y 5mL de solución absorbente formada por agua destilada y una mezcla al 50% molar de hexano-tolueno. En la torre de destilación se obtuvieron 0,002483 ppm y 0,002742 ppm de etanol, y en la torre de extracción 0,00125 ppm y 0,000758 ppm de hexano para cada medio. Estos resultados se compararon con los reportados en las normas oficiales Venezolanas (COVENIN, 1993), concluyéndose que las concentraciones de etanol y hexano en el área de estudio están por debajo de las concentraciones máximas permitidas.