RESUMO

Abstract Agave cocui vinasse was physicochemically characterized with reference to the relevant environmental regulations. The following results were obtained: COD: 71,000 mg.L-1, total solids: 21,000 mg.L-1, dissolved solids: 17,000 mg.L-1; pH: 4.06, conductivity: 9.45 mhoscm-1, total Fe: 48.83 mg.L-1, total phenols: 8.66 mg.L-1; BOD: 30,000 mg.L-1. Fenton and photo-Fenton reactions were applied to treat the wastewater produced. For the Fenton process, the optimal oxidation conditions found were pH = 3.48, [COD]:[H2O2] mass ratio = 1:5, and [Fe+2]: [H2O2] mass ratio = 1:6. For the photo-Fenton process, the optimal parameters found were: pH = 3.98, [COD]:[H2O2] = 1:7.86, and [Fe+2]: [H2O2] = 1:5. The experimental data were adjusted to fit second order polynomial models with R2 = 0.88 for the Fenton process and R2 = 0.91 for the photo-Fenton process, respectively. The sludge produced featured the following characteristics: average COD: 41,000 mg.L-1, total Fe: 296,000 mg.L-1, pH: 7.7. The variables with the greatest influence in both processes were [Fe+2]:[H2O2] and [COD]:[H2O2].

Resumen Se caracterizó fisicoquímicamente la vinaza de Agave cocui con base en regulaciones ambientales de referencia. Se obtuvieron los siguientes resultados: DQO: 71 000 mg.L-1, sólidos totales: 21 000 mg.L-1, sólidos disueltos: 17 000 mg.L-1; pH: 4,06, conductividad: 9,45 mhos.cm-1, hierro total: 48,83 mg.L-1, fenoles totales: 8,66 mg.L-1 ; DBO: 30 000 mg.L-1. Se aplicaron las reacciones Fenton y foto Fenton para tratar las aguas residuales producidas. Para el proceso Fenton, las condiciones de oxidación óptimas encontradas fueron pH = 3,48, relación de masa [DQO]:[H2O2] = 1:5 y relación de masa [Fe+2]:[H2O2] = 1:6. Para el proceso foto Fenton, los parámetros óptimos encontraron fueron: pH = 3,98, [DQO]:[H2O2] = 1:7,86 y [Fe+2]:[H2O2] = 1:5. Los datos experimentales fueron ajustados a modelos de segundo orden polinomial con R2 = 0,88 para el proceso Fenton y R2 = 0,91 para el proceso foto Fenton, respectivamente. El lodo producido presentó las siguientes características: DQO promedio: 41 000 mg.L-1, hierro total: 296 000 mg.L-1, pH: 7,7. Las variables con mayor influencia en ambos procesos fueron [Fe+2]:[H2O2] and [DQO]: [H2O2].

Resumo A vinhaça de Agave cocui foi caracterizada físico-quimicamente de acordo com as normas ambientais de referência. Os seguintes resultados foram obtidos: DQO: 71.000 mg.L-1, sólidos totais: 21.000 mg.L-1, sólidos dissolvidos: 17.000 mg.L-1; pH: 4,06, condutividade: 9,45 mhos.cm-1, Fe total: 48,83 mg.L-1, fenóis totais: 8,66 mg.L-1; DBO: 30,000 mg.L-1. As reações de Fenton e foto Fenton foram aplicadas para tratar a água residual produzida. Para o processo Fenton, as condições de oxidação ideais encontradas foram pH = 3,48, razão de massa [DQO]:[H2O2] = 1:5 e razão de massa [Fe+2]:[H2O2] = 1:6. Para o processo de foto Fenton, os parâmetros ideais encontrados foram: pH = 3,98, [DQO]:[H2O2] = 1:7,86 e [Fe+2]:[H2O2] = 1:5. Os dados experimentais foram ajustados para se adequar modelos polinomiais de segunda ordem com R2 = 0,88 para o processo Fenton e R2 = 0,91 para o processo foto Fenton, respectivamente. O lodo produzido apresentou as seguintes características: DQO média: 41.000 mg.L-1, Fe total: 296.000 mg.L-1, pH: 7,7. As variáveis com maior influência em ambos os processos foram [Fe+2]:[H2O2] e [DQO]:[H2O2].

RESUMO

The use of heating systems for new-born piglets can prevent major losses in the first 5 weeks of life. The present study had the objective of evaluating three heating systems in creeps for new-born piglets, being: floor-heated floor with circulating water (HF), incandescent lamp type SPOT 40 W (L) and incandescent lamp type SPOT 40 W plus black metal plate (LP). The variables evaluated were piglet performance (total weight gain and mortality), bioclimatic data (temperature and relative air humidity), animal behaviour and economic revenue. Bioclimatic data were recorded in the external environment, in the maternity and in the interior of each shelter/creep for 21 days, three times a day, as well as the capture of photographic images for analysis of the animals' disposal. The mean temperature of the retractors, the weight at weaning and the weight gain were higher in the HF treatment. Treatment HF improved the percentage of dispersed animals and provided the best thermal environment and the highest revenue at the time of the commercialization of the piglets.

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RESUMO

A suinocultura traz desenvolvimento econômico, mas causa problemas ambientais graves, devido aos resíduos sólidos gerados, que em geral não são tratados adequadamente. O objetivo do trabalho é fazer o estudo técnico-econômico de implantação de biodigestores para o tratamento de dejetos suínos, com geração de biogás que será transformado em energia elétrica e térmica para o abastecimento de uma pequena propriedade rural. Com isso, pretende-se reduzir a dependência de adubos químicos, de energias térmica e elétrica para os diversos usos (aquecimento de campânulas no aviário, iluminação e resfriamento), reduzir a poluição e a emissão de gases de efeito estufa. Foram dimensionados dois biodigestores (55 m³ cada), gerando 41,8 m³ de biogás por dia cada. O tempo de retenção hidráulica foi de 30 dias. Serão gerados biofertilizante e biogás, esse último sendo canalizado e podendo seguir ou para as campânulas, ou para o motor-gerador que o transformará em energia elétrica para a propriedade. O sistema projeto apresenta melhorias, analisando os aspectos ambientais, econômicos para o agricultor e sociais para a comunidade, além de ser uma forma mais eficiente de utilização dos recursos da propriedade.

Swine production brings economic development, but causes serious environmental problems, due to the solid residues generated which generally are not adequately treated. The objective of this research is to carry out a technical-economic study of the implantation of biodigestive deposits for the treatment of swine excrements with generation of biogas, which will be transformed in electrical and thermal energy to be supplied to a small rural property. This is intended to reduce the dependence on chemical fertilizers, electrical, and thermal energy for several uses (aviary heaters, lighting, and cooling), reduction of pollution and of emission of greenhouse gases. Two 55m³ biodigestive deposits were projected, each generating 41.8 m³ of biogas per day. The period of hydraulic retention was 30 days. Biofertilizer and biogas will be generated. The biogas will be conducted by pipes either to the heaters or to the generator-motor, which will transform it in electrical energy for the property. Once installed, the system presents improvements, analyzing environmental and economical aspects for the farmer and social aspects for the community. It is a more efficient way to use the resources of the property.

Assuntos

RESUMO

A suinocultura traz desenvolvimento econômico, mas causa problemas ambientais graves, devido aos resíduos sólidos gerados, que em geral não são tratados adequadamente. O objetivo do trabalho é fazer o estudo técnico-econômico de implantação de biodigestores para o tratamento de dejetos suínos, com geração de biogás que será transformado em energia elétrica e térmica para o abastecimento de uma pequena propriedade rural. Com isso, pretende-se reduzir a dependência de adubos químicos, de energias térmica e elétrica para os diversos usos (aquecimento de campânulas no aviário, iluminação e resfriamento), reduzir a poluição e a emissão de gases de efeito estufa. Foram dimensionados dois biodigestores (55 m³ cada), gerando 41,8 m³ de biogás por dia cada. O tempo de retenção hidráulica foi de 30 dias. Serão gerados biofertilizante e biogás, esse último sendo canalizado e podendo seguir ou para as campânulas, ou para o motor-gerador que o transformará em energia elétrica para a propriedade. O sistema projeto apresenta melhorias, analisando os aspectos ambientais, econômicos para o agricultor e sociais para a comunidade, além de ser uma forma mais eficiente de utilização dos recursos da propriedade.(AU)

Swine production brings economic development, but causes serious environmental problems, due to the solid residues generated which generally are not adequately treated. The objective of this research is to carry out a technical-economic study of the implantation of biodigestive deposits for the treatment of swine excrements with generation of biogas, which will be transformed in electrical and thermal energy to be supplied to a small rural property. This is intended to reduce the dependence on chemical fertilizers, electrical, and thermal energy for several uses (aviary heaters, lighting, and cooling), reduction of pollution and of emission of greenhouse gases. Two 55m³ biodigestive deposits were projected, each generating 41.8 m³ of biogas per day. The period of hydraulic retention was 30 days. Biofertilizer and biogas will be generated. The biogas will be conducted by pipes either to the heaters or to the generator-motor, which will transform it in electrical energy for the property. Once installed, the system presents improvements, analyzing environmental and economical aspects for the farmer and social aspects for the community. It is a more efficient way to use the resources of the property.(AU)

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RESUMO

Pseudostem of the Musa cavendishii banana plant was submitted to chemical pretreatments with acid (H2SO4 2%, 120 °C, 15 min) and with alkali (NaOH 3%, 120 °C, 15 min), saccharified by commercial enzymes Novozymes® (Cellic CTec2 and HTec2). The influences of the pretreatments on the degradation of the lignin, cellulose and hemicellulose, porosity of the surface, particle crystallinity, and yield in reducing sugars after saccharification (Y RS), were established. Different concentrations of biomass (70 and 100 g/L in dry matter (dm)), with different physical differences (dry granulated, crushed wet bagasse, and whole pseudostem), were used. The broth with the highest Y RS among the different strategies tested was evaporated until the concentration of reducing sugars (RS) was to the order of 100 g/L and fermented, with and without prior detoxification with active carbon. Fermentation was carried out in Erlenmeyer flasks, at 30 °C, initial pH 5.0, and 120 rpm. In comparison to the biomass without chemical pretreatment and to the biomass pretreated with NaOH, the acid pretreatment of 70 g/L of dry granulated biomass enabled greater digestion of hemicellulose, lower index of cellulose crystallinity, and higher Y RS (45.8 ± 0.7%). The RS increase in fermentation broth to 100 g/L, with posterior detoxification, presented higher productivity ethanol (Q P = 1.44 ± 0.02 g/L/h) with ethanol yield (Y P/RS) of 0.41 ± 0.02 g/g. The value of Q P was to the order of 75% higher than Q P obtained with the same broth without prior detoxification.

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Background: Fermentation process development has been very important for efficient ethanol production. Improvement of ethanol production efficiency from sweet sorghum juice (SSJ) under normal gravity (NG, 160 g/L of sugar), high gravity (HG, 200 and 240 g/L of sugar) and very high gravity (VHG, 280 and 320 g/L of sugar) conditions by nutrient supplementation and alternative feeding regimes (batch and fed-batch systems) was investigated using a highly ethanol-tolerant strain, Saccharomyces cerevisiae NP01. Results: In the batch fermentations without yeast extract, HG fermentation at 200 g/L of sugar showed the highest ethanol concentration (PE, 90.0 g/L) and ethanol productivity (QE, 1.25 g/L·h). With yeast extract supplementation (9 g/L), the ethanol production efficiency increased at all sugar concentrations. The highest PE (112.5 g/L) and QE (1.56 g/L·h) were observed with the VHG fermentation at 280 g/L of sugar. In the fed-batch fermentations, two feeding regimes, i.e., stepwise and continuous feedings, were studied at sugar concentrations of 280 g/L. Continuous feeding gave better results with the highest PE and QE of 112.9 g/L and 2.35 g/L·h, respectively, at a feeding time of 9 h and feeding rate of 40 g sugar/h. Conclusions: In the batch fermentation, nitrogen supplementation resulted in 4 to 32 g/L increases in ethanol production, depending on the initial sugar level in the SSJ. Under the VHG condition, with sufficient nitrogen, the fed-batch fermentation with continuous feeding resulted in a similar PE and increased QP by 51% compared to those in the batch fermentation.

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