The aim of this study was to develop an effective and economically viable technology for the treatment of vinasse, prior to its disposal in the soil for fertirrigation, aiming this way at reducing the environmental impacts generated by inadequately discarding this effluent. The primary treatment of vinasse by adsorption was evaluated. Adsorbents were prepared from sugar cane bagasse and their efficiency evaluated in relation to the treatment of vinasse. The process of preparation of activated carbon consisted of carbonizing bagasse at different temperatures followed by chemical activation with NaOH. The carbon samples obtained by solely carbonizing sugar cane bagasse were more efficient for removing turbidity of vinasse than samples activated with NaOH. The sample carbonized at 800 °C was the most efficient for removing turbidity of wastewater (83%). During a process of adsorption of vinasse in two stages, it was possible to obtain color removal, turbidity and COD of approximately 76, 85 and 69%, respectively. After the adsorption step of vinasse, the solid waste generated in the second stage of adsorption can be burned in the boilers of the power plant itself, affording an energy of 4606 cal g-1.

Biofilmes confeccionados à base de alginato de sódio foram reticulados com íons Ca++ provenientes de duas fontes, cloreto e benzoato de cálcio, e continham glicerol como plastificante. Inicialmente, devido ao alto poder gelificante do Ca++, um filme de baixo grau de reticulação foi confeccionado por casting (1º estágio). Esse filme sofreu uma reticulação complementar por imersão em uma solução contendo de 3 a 7% de CaCl2.2H2O, além de glicerol (2º estágio). A liberação de benzoato de cálcio foi avaliada em diferentes concentrações de agente ativo no filme e dois níveis de reticulação do alginato. O mecanismo envolvido no processo de difusão foi investigado usando o modelo da Lei de Potência. Os resultados indicaram que a difusão de benzoato de cálcio em filmes de alginato apresenta características de comportamentos Fickiano e não-Fickiano. Os coeficientes de difusão efetivos obtidos usando a solução em série derivada da 2ª Lei de Fick são próximos aos valores obtidos pela solução em tempos curtos, com valores de difusividade efetiva do benzoato variando de 3 a 5.10-7 cm²/s. Os valores de difusividade diminuíram com o aumento da intensidade de reticulação e aumentaram com a concentração de benzoato no filme.

Alginate-based biofilms were reticulated with Ca++ supplied by two sources, calcium chloride and benzoate, and using glycerol as plasticizer. The strong gelling power of the Ca++ ions hindered smooth casting procedures, so that films with low degree of reticulation were initially manufactured (1st stage). These films were further crosslinked with an excess of Ca++ by immersion in a solution of 3 to 7% of CaCl2.2H2O (2nd stage). The release of sorbate was evaluated considering different active agent concentrations in the film and two levels of alginate crosslinking. The mechanism involved in the diffusional process was investigated using the Power Law Model. The results indicated that potassium sorbate diffusion in alginate films has characteristics of Fickian and non-Fickian behavior. Effective diffusion coefficients obtained using the solution in series derived from Fick’s Second Law are close to values obtained with the short-time solution, with effective diffusivities varying from 3 to 5 × 10-7 cm²/s. The diffusivity values decreased with the degree of reticulation and increase with benzoate concentration in the film.

Pre-treatment processes to remove fat and mineral salts from acid whey in order to recover its proteins and lactose contents were studied. Separation processes such as centrifugation and thermocalcic precipitation followed by microfiltration were analyzed. The centrifugation process combined with microfiltration process was more efficient for removing fat, resulting in an average lactose and protein recovery of 90%.

Se estudiaron procesos de pre-tratamiento para la eliminación de grasas y sales minerales del suero de queso tipo ácido, para el aprovechamiento del contenido de proteínas y lactosa. Se analizaron procesos de separación tales como centrifugación y precipitación termo-cálcica seguidos de una etapa de micro-filtración. El proceso de centrifugación combinado con micro-filtración se mostró más eficiente en lo que se refiere a la eliminación de grasa, obteniéndose un promedio de 90% de recuperación de proteínas y de lactosa.

This paper describes the synthesis of asymmetric polymer membranes used for the production of drinking water. Filtration of water through the membranes is an alternative method for water treatment, where the membrane acts as a selective barrier which blocks the passage of some components. Water samples for this study were inoculated with 10(7) to 10(8) colony forming units (CFU) of Escherichia coli per ml. The process used was phase inversion, and the membranes were prepared beginning with polymer solutions, including polysulfone and polyvinylidene fluoride. In both cases polymethyl methacrylate was added to the polymeric solutions, using N,N-dimethylformamide as solvent. Some of the membranes prepared achieved bacterial removal of 99 to 100%, at a flow of 300 L/h m²

En este trabajo se presenta un estudio sobre la síntesis de membranas poliméricas asimétricas para la producción de agua potable. La filtración usando membranas es un proceso alternativo para el tratamiento de aguas, donde la membrana actúa como una barrera selectiva que bloquea el pasaje de algunos componentes. En este trabajo algunas muestras de agua fueron infectadas con 10(7) a 10(8) unidades formadoras de colonias (UFC) por ml con la bacteria Escherichia coli. El proceso utilizado fue la inversión de fases y las membranas fueron preparadas a partir de soluciones poliméricas, con polisulfona y con fluoruro de polivinilideno. En ambos casos, se agregó poli metacrilato de metilo a las soluciones poliméricas, usando N,N-dimetilformamida como solvente. Algunas membranas removieron entre 99 y 100% de las colonias bacterianas, con un flujo de 300 L/h m²