RESUMEN
The impact of electrode corrosion behaviour, reactor geometry and current density on electrocoagulation efficiency were investigated for the treatment of molasses process wastewater. Two laboratory-scale vertical plate electrocoagulation reactors were used for this investigation: the first being a low aspect ratio bath reactor with a low specific electrode area, while the other was a high aspect ratio column reactor with a high specific electrode area. Anomalous anodic dissolution and cathodic corrosion of the aluminium electrodes both contributed significantly to overall metal consumption. Increasing specific electrode area and aspect ratio each led to improved treatment efficiency, whereas the impact of current density was more complicated involving the combined influences of several competing effects. The space-time yields of coagulant and bubbles (both functions of specific electrode area, current density and current efficiency) were found to influence mixing within the reactor and thus treatment efficiency.
Asunto(s)
Electrocoagulación/métodos , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Aluminio/análisis , Cloruros/análisis , Electrocoagulación/instrumentación , Electrocoagulación/normas , Electrodos , Diseño de Equipo , Alimentos , Concentración de Iones de Hidrógeno , Hierro/análisis , Eliminación de Residuos Líquidos/instrumentación , Purificación del Agua/normasRESUMEN
A nonlinear model of a recombinant Escherichia coli producing porcine growth hormone (pGH) fermentation was developed. The model was used to calculate a glucose feeding and temperature strategy to optimize the production of pGH. Simulations showed that the implementation of optimal feed and temperature profiles was sensitive to the maximum specific growth rate, and a mismatch could result in excessive acetate production and a significant reduction in pGH yield. An optimization algorithm was thus developed, using feedback control, to counter the effects of uncertainty in the specific growth rate and thus determine an optimal operating strategy for pGH production. This policy was experimentally implemented in a 10 L fermenter and resulted in a 125% increase in productivity over the previous best experimental result with this system--in spite of significant plant-model mismatch.
Asunto(s)
Algoritmos , Reactores Biológicos/microbiología , Técnicas de Cultivo de Célula/métodos , Escherichia coli/metabolismo , Hormona del Crecimiento/biosíntesis , Modelos Biológicos , Ingeniería de Proteínas/métodos , Animales , Simulación por Computador , Hormona del Crecimiento/genética , Control de Calidad , Proteínas Recombinantes/biosíntesis , PorcinosRESUMEN
Electrocoagulation removes pollutant material from water by a combination of coagulant delivered from a sacrificial aluminium anode and hydrogen bubbles evolved at an inert cathode. Rates of clay particle flotation and settling were experimentally determined in a 7 L batch reactor over a range of currents (0.25-2.0 A) and pollutant loadings (0.1-1.7 g/L). Sedimentation and flotation are the dominant removal mechanism at low and high currents, respectively. This shift in separation mode can be explained by analysing the reactor in terms of a published dissolved air flotation model.
Asunto(s)
Silicatos de Aluminio/aislamiento & purificación , Electroquímica/métodos , Aguas del Alcantarillado/microbiología , Contaminantes del Agua/aislamiento & purificación , Purificación del Agua/métodos , Aluminio/química , Reactores Biológicos , Arcilla , Arquitectura y Construcción de Instituciones de Salud , Hidrógeno/química , Modelos Teóricos , Aguas del Alcantarillado/química , Factores de TiempoRESUMEN
In animal cell culture, there are some 25 substrates that both have a significant effect on the culture performance and which can be measured with relative ease. A detailed dynamic simulation for such a culture has been produced and an optimisation policy that use this model to identify ideal media conditions has been developed. This paper describes an extension of that work to include the dynamic optimisation of cultures under fed-batch operation. Two different types of feeding policy were considered - in the first, discrete shots of feed were supplied, while in the second, feed was added continuously. Both policies offered significant improvements in the predicted productivity of the culture - up to 30% that of an experimentally "optimised"batch culture.