The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Tom Stephenson - One of the best experts on this subject based on the ideXlab platform.
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biomass effects on Oxygen Transfer in membrane bioreactors
Water Research, 2007Co-Authors: E Germain, F Nelles, E Reid, S J Judd, Pete Pearce, Matthias Kraume, Anja Drews, Tom StephensonAbstract:Fine bubble aeration and biomass characteristics were studied for their impact on Oxygen Transfer in membrane bioreactors (MBRs). Ten biomass samples from both municipal and industrial pilot and full scale submerged MBRs with mixed liquor suspended solids concentrations (MLSS) ranging from 7.2 to 30.2 g.L -1 were studied at six air flow rates (0.7, 1.3, 2.3, 3, 4.4 and 6 m 3 .m -3 .h -1 ). Graphical and statistical analyses were applied to the results to identify the relative impacts of the various bulk biomass characteristics on Oxygen Transfer, the former being solids concentration,
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Biomass effects on Oxygen Transfer in membrane bioreactors.
Water research, 2007Co-Authors: E Germain, F Nelles, E Reid, Pete Pearce, Matthias Kraume, Anja Drews, Simon Judd, Tom StephensonAbstract:Ten biomass samples from both municipal and industrial pilot and full scale submerged membrane bioreactors (MBRs) with mixed liquor suspended solids concentrations (MLSS) ranging from 7.2 to 30.2g L(-1) were studied at six air-flow rates (0.7, 1.3, 2.3, 3, 4.4 and 6m(3)m(-3)h(-1)). Statistical analyses were applied to identify the relative impacts of the various bulk biomass characteristics on Oxygen Transfer. Of the biomass characteristics studied, only solids concentration (correlated with viscosity), the carbohydrate fraction of the EPS (EPS(c)) and the chemical Oxygen demand (COD) concentration of the SMP (SMP(COD)) were found to affect the Oxygen Transfer parameters k(L)a(20) (the Oxygen Transfer coefficient) and alpha-factor. The relative influence on k(L)a(20) was MLSS>aeration>EPS(c)>SMP(COD) and on alpha-factor was MLSS>SMP(COD)>EPS(c)>aeration. Both k(L)a(20) and alpha-factor increased with increasing aeration and EPS(c) and decreased with increasing MLSS and SMP(COD). MLSS was found to be the main parameter controlling the Oxygen Transfer.
V. Milisic - One of the best experts on this subject based on the ideXlab platform.
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Modelling of Oxygen Transfer in wines
Chemical Engineering Science, 2010Co-Authors: R. Adoua, Martine Mietton-peuchot, V. MilisicAbstract:Abstract The micro-Oxygenation is a technique now admitted in various stages of winemaking. However, in practice, its application remains difficult and its control is uncertain. Since in a several meter large and high tank, the Oxygen is distributed through a bubbler having few square centimetres, the behaviour of bubbles, their influence on liquid phase and the Transfer of the Oxygen from bubbles to wine, the involved phenomena are very complex. To day, the wine testing is still the most often use as main indicator in Oxygenation management. The article presents numerical simulation of flow created by bubbles rising, Oxygen Transfer trough the bubble/liquid interface and its diffusion in wine. The Navier–Stokes equations and the transport equation of concentration are integrated in two dimensions by the finite volume method using the Euler–Euler approach, with the help of numerical software PHOENICS; the turbulence in the liquid phase is described using the k – e model. The flow structure shows the presence of two zones recirculation that developed close to the tank walls. The results on the Oxygen Transfer show that the Transfer is highly dependent on the diameter and height of the tank.
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Modelling of Oxygen Transfer in wines
Chemical Engineering Science, 2010Co-Authors: R. Adoua, Martine Mietton-peuchot, V. MilisicAbstract:The micro-Oxygenation is a technique now admitted in various stages of winemaking. However, in practice, its application remains difficult and its control is uncertain. Since in a several meter large and high tank, the Oxygen is distributed through a bubbler having few square centimetres, the behaviour of bubbles, their influence on liquid phase and the Transfer of the Oxygen from bubbles to wine, the involved phenomena are very complex. To day, the wine testing is still the most often use as main indicator in Oxygenation management. The article presents numerical simulation of flow created by bubbles rising, Oxygen Transfer trough the bubble/liquid interface and its diffusion in wine. The Navier–Stokes equations and the transport equation of concentration are integrated in two dimensions by the finite volume method using the Euler–Euler approach, with the help of numerical software PHOENICS; the turbulence in the liquid phase is described using the k–ε model. The flow structure shows the presence of two zones recirculation that developed close to the tank walls. The results on the Oxygen Transfer show that the Transfer is highly dependent on the diameter and height of the tank.
E Germain - One of the best experts on this subject based on the ideXlab platform.
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biomass effects on Oxygen Transfer in membrane bioreactors
Water Research, 2007Co-Authors: E Germain, F Nelles, E Reid, S J Judd, Pete Pearce, Matthias Kraume, Anja Drews, Tom StephensonAbstract:Fine bubble aeration and biomass characteristics were studied for their impact on Oxygen Transfer in membrane bioreactors (MBRs). Ten biomass samples from both municipal and industrial pilot and full scale submerged MBRs with mixed liquor suspended solids concentrations (MLSS) ranging from 7.2 to 30.2 g.L -1 were studied at six air flow rates (0.7, 1.3, 2.3, 3, 4.4 and 6 m 3 .m -3 .h -1 ). Graphical and statistical analyses were applied to the results to identify the relative impacts of the various bulk biomass characteristics on Oxygen Transfer, the former being solids concentration,
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Biomass effects on Oxygen Transfer in membrane bioreactors.
Water research, 2007Co-Authors: E Germain, F Nelles, E Reid, Pete Pearce, Matthias Kraume, Anja Drews, Simon Judd, Tom StephensonAbstract:Ten biomass samples from both municipal and industrial pilot and full scale submerged membrane bioreactors (MBRs) with mixed liquor suspended solids concentrations (MLSS) ranging from 7.2 to 30.2g L(-1) were studied at six air-flow rates (0.7, 1.3, 2.3, 3, 4.4 and 6m(3)m(-3)h(-1)). Statistical analyses were applied to identify the relative impacts of the various bulk biomass characteristics on Oxygen Transfer. Of the biomass characteristics studied, only solids concentration (correlated with viscosity), the carbohydrate fraction of the EPS (EPS(c)) and the chemical Oxygen demand (COD) concentration of the SMP (SMP(COD)) were found to affect the Oxygen Transfer parameters k(L)a(20) (the Oxygen Transfer coefficient) and alpha-factor. The relative influence on k(L)a(20) was MLSS>aeration>EPS(c)>SMP(COD) and on alpha-factor was MLSS>SMP(COD)>EPS(c)>aeration. Both k(L)a(20) and alpha-factor increased with increasing aeration and EPS(c) and decreased with increasing MLSS and SMP(COD). MLSS was found to be the main parameter controlling the Oxygen Transfer.
R. Adoua - One of the best experts on this subject based on the ideXlab platform.
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Modelling of Oxygen Transfer in wines
Chemical Engineering Science, 2010Co-Authors: R. Adoua, Martine Mietton-peuchot, V. MilisicAbstract:Abstract The micro-Oxygenation is a technique now admitted in various stages of winemaking. However, in practice, its application remains difficult and its control is uncertain. Since in a several meter large and high tank, the Oxygen is distributed through a bubbler having few square centimetres, the behaviour of bubbles, their influence on liquid phase and the Transfer of the Oxygen from bubbles to wine, the involved phenomena are very complex. To day, the wine testing is still the most often use as main indicator in Oxygenation management. The article presents numerical simulation of flow created by bubbles rising, Oxygen Transfer trough the bubble/liquid interface and its diffusion in wine. The Navier–Stokes equations and the transport equation of concentration are integrated in two dimensions by the finite volume method using the Euler–Euler approach, with the help of numerical software PHOENICS; the turbulence in the liquid phase is described using the k – e model. The flow structure shows the presence of two zones recirculation that developed close to the tank walls. The results on the Oxygen Transfer show that the Transfer is highly dependent on the diameter and height of the tank.
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Modelling of Oxygen Transfer in wines
Chemical Engineering Science, 2010Co-Authors: R. Adoua, Martine Mietton-peuchot, V. MilisicAbstract:The micro-Oxygenation is a technique now admitted in various stages of winemaking. However, in practice, its application remains difficult and its control is uncertain. Since in a several meter large and high tank, the Oxygen is distributed through a bubbler having few square centimetres, the behaviour of bubbles, their influence on liquid phase and the Transfer of the Oxygen from bubbles to wine, the involved phenomena are very complex. To day, the wine testing is still the most often use as main indicator in Oxygenation management. The article presents numerical simulation of flow created by bubbles rising, Oxygen Transfer trough the bubble/liquid interface and its diffusion in wine. The Navier–Stokes equations and the transport equation of concentration are integrated in two dimensions by the finite volume method using the Euler–Euler approach, with the help of numerical software PHOENICS; the turbulence in the liquid phase is described using the k–ε model. The flow structure shows the presence of two zones recirculation that developed close to the tank walls. The results on the Oxygen Transfer show that the Transfer is highly dependent on the diameter and height of the tank.
Bimlesh Kumar - One of the best experts on this subject based on the ideXlab platform.
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Oxygen Transfer WITH CIRCULATION FLOW RATE IN UNBAFFLED SURFACE AERATOR
Chemistry & Chemical Technology, 2012Co-Authors: Bimlesh Kumar, Thiyam Tamphasana DeviAbstract:Circulation flow rate and vortex in unbaffled surface aeration systems are interrelated. These properties exert a profound effect on the performance of the surface aeration systems affecting the Oxygen Transfer process. This work develops the scale up criteria for Oxygen Transfer rate based on the circulation flow rate. A relationship between circulation flow rate and vortex depth in surface aerators has been also developed.
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Oxygen Transfer and shear rate in surface aerator
Environmental Technology, 2009Co-Authors: Bimlesh KumarAbstract:Shear rate in a surface aeration system exerts a profound effect on its performance, affecting the mixing pattern, the power requirement and Oxygen Transfer process. Based on theoretical analysis, it is shown that the shear rate γ in the fluid is a function of the rotational speed N of the impeller in surface aeration systems. Analysis shows that the shear rate varies linearly with N in laminar flow and its behaviour is non‐linear in a turbulent flow regime. Experimental correlations of γ with N have been developed in the present study for different sized surface aerators. Scale‐up or scale‐down criteria for Oxygen Transfer rate have been developed, which relate Oxygen Transfer rate to shear rate in surface aeration systems.
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Oxygen Transfer and energy dissipation rate in surface aerator
Bioresource Technology, 2009Co-Authors: Bimlesh Kumar, Achanta Ramakrishna RaoAbstract:The dissipation rate of turbulent kinetic energy(e)is a key parameter for mixing in surface aerators. In particular, determination e across the impeller stream, where the most intensive mixing takes place, is essential to ascertain that an appropriate degree of mixing is achieved. Present work by using commercial software VisiMix calculates the energy dissipation rate in geometrically similar unbaffled surface aeration systems in order to scale-up the Oxygen Transfer process. It is found that in geometrically similar system,Oxygen Transfer rate is uniquely correlated with dissipation rate of energy. Simulation or scale-up equation governing Oxygen Transfer rate and dissipation rate of energy has been developed in the present work.
