Effect of additives on mass transfer in turbine aeration

Benedek, Andrew; Heideger, W. J.

doi:10.1002/bit.260130507

Cited by 39 publications

(14 citation statements)

References 22 publications

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“…every 15 minutes. The oxygen mass transfer coefficient k L a of the bioreactor was taken into account and measured as described by the procedure proposed by Benedek and Heideger [13] and adapted by Sheppard [14]. All aerobic experiments were conducted at room temperature (22°C).…”

Section: Methodsmentioning

confidence: 99%

Comparison of the Biodegradation of n-alkanes and Readily Biodegradable Substrates Using Open Mixed Culture under Aerobic, Anoxic and Anaerobic Conditions

Uzukwu¹,

Dionisi²

2017

IJEBB

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This study has investigated the biodegradation of n-alkanes using open mixed cultures in batch tests.Biodegradation of n-C12, C14, C16, C18, C20 was investigated using a respirometric method and compared with the biodegradation of the readily biodegradable substrates glucose, acetic acid and ethanol. Experiments were performed in small-scale bioreactors under various conditions, i.e. aerobic, anoxic with nitrate and completely anaerobic conditions, using two different sources of open mixed microbial cultures. Under aerobic conditions all the readily biodegradable substrates and hydrocarbons were removed, although the acclimation time was longer for the hydrocarbons (3-5 days) than for the readily biodegradable substrates (1-2 days). No significant effect on the hydrocarbon concentration on biodegradation was observed in the concentration range 0.5-5 g/l. Under anoxic conditions, both the readily biodegradable substrates and the hydrocarbons were removed using nitrate as electron acceptor. However, the acclimation time for the hydrocarbons under anoxic conditions (20-25 days) was much longer than under aerobic conditions. Under both aerobic and anoxic conditions, once acclimation with the hydrocarbons was completed, the microorganisms were immediately able to remove a second spike of the substrate without acclimation. Under anaerobic conditions, no activity was observed with the hydrocarbons over a period of 150 days, while the mixed culture was able to remove glucose and convert it to volatile fatty acids. Under aerobic conditions, the dissolved oxygen consumption data was mathematically modelled using Monod kinetics to obtain biokinetic parameters. Good fittings between the model and the experimental data was obtained and the biodegradation of hydrocarbons was characterised by higher values of the parameter K S compared to the readily biodegradable substrates. The results of this study showed that the open mixed microbial cultures contained diverse microorganisms capable of utilizing both liquid and solid n-alkanes under aerobic and anoxic conditions.

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Section: Methodsmentioning

confidence: 99%

Comparison of the Biodegradation of n-alkanes and Readily Biodegradable Substrates Using Open Mixed Culture under Aerobic, Anoxic and Anaerobic Conditions

Uzukwu¹,

Dionisi²

2017

IJEBB

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“…Sheppard and Cooper (1990) suggest that the diffusional resistance effect will dominate at low surfactant concentrations (therefore, KLa will decrease), while at high surfactant concentrations the interfacial area effect will predominate (therefore, KLa will increase). Results obtained by Benedek and Heideger (1971) indicate that the agitation rate does not affirect ....... ~L ; thus, the effect of agitation on KLa is through its effect on the interfacial area. If this is true, then the results obtained at 0.07 vvm indicate that the effect of agitation on theinterfacial area is reduced when Pluronic F-68 is present.…”

Section: Resultsmentioning

confidence: 88%

“…Lavery and Nienow found that used TNM-FH insect cell culture medium agitated by a single rnarine impeller of 4 cm diameter. Benedek and Heideger (1971) found that adding antifoam to water inhibited KLa less at 255 rpm than at higher agitation rates when sparged at 0.39 vvm. All of these results demonstrate that at a low sparge rate the addition of either antifoam or Pluronic F-68 results in an increased inhibition of KLa as the agitation rate is increased.…”

Section: Resultsmentioning

confidence: 97%

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Effects of pluronic F-68 on oxygen transport in an agitated, sparged bioreactor

Murhammer

Pfalzgraf

1992

Biotechnol Tech

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The gassing out method was used to study the effect of Pluronic F-68 on oxygen transport in an agitated, sparged bioreactor. At a low air sparge rate (0.07 vvm), the addition of Pluronic F-68 had a minimal effect on KLa in both water and medium at low agitation rates. As the agitation rate was increased at this low sparge rate the relative inhibitory effect of Pluronic F-68 on KLa increased with increasing agitation rate. At an air sparge rate of 0.80 wm, the addition of Pluronic F-68 resulted in a significant reduction in KLa at all agitation rates studied.

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“…Similarly, the presence of surfactants can reduce k L by reducing turbulence on a microscopic scale in the interfacial region. Therefore, the net effect of electrolytes and surfactants can be an increase or a decrease in kia [78].…”

Section: The Effect Of Solution Compositionmentioning

confidence: 99%

Gas–Liquid Oxygen Mass-transfer; from Fundamentals to Applications in Hydrometallurgical Systems

Filippou

Cheng

Demopoulos

2000

Mineral Processing and Extractive Metallurgy Review

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Oxygen gas is used as a reactant in many hydrometallurgical processes. However, oxygen is sparingly soluble in aqueous electrolyte solutions, and the driving force for its masstransfer from the gas to the aqueous phase is also very low. Hence, the mass-transfer of oxygen depends significantly on the interfacial area between the gas and the liquid phase, which in turn depends on the mixing conditions inside the reactor. A change in the solution composition or the presence of solids can further alter the rate of oxygen masstransfer. All such phenomena related to the gas-liquid oxygen mass-transfer in hydrometallurgical unit operations are critically reviewed in the present article -from the basic thermodynamics and kinetics of oxygen dissolution in aqueous solutions to the most recent advances in oxygen mass-transfer systems.

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Effect of additives on mass transfer in turbine aeration

Cited by 39 publications

References 22 publications

Comparison of the Biodegradation of n-alkanes and Readily Biodegradable Substrates Using Open Mixed Culture under Aerobic, Anoxic and Anaerobic Conditions

Comparison of the Biodegradation of n-alkanes and Readily Biodegradable Substrates Using Open Mixed Culture under Aerobic, Anoxic and Anaerobic Conditions

Effects of pluronic F-68 on oxygen transport in an agitated, sparged bioreactor

Gas–Liquid Oxygen Mass-transfer; from Fundamentals to Applications in Hydrometallurgical Systems

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