Estimation of oxygen transfer rate in sequencing batch reactor

1996 ◽  
Vol 34 (3-4) ◽  
pp. 413-420
Author(s):  
Y. C. Liao ◽  
D. J. Lee
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Oxygen Transfer Rate ◽  
Intermittent Aeration ◽  
Transient Effects ◽  
Operational Parameters ◽  
Transient Model

Transient model of oxygen transfer rate in a sequencing batch reactor is derived and solved numerically. The dissolved oxygen response under several conditions is analyzed. Effects of operational parameters and liquid bath height are studied. When with short, intermittent aeration periods, the transient effects on oxygen transfer rate may be substantial and should be taken into considerations. An example considering bioreaction is also given.

Effect of oxygen-transfer rate on production of L-asparaginase by Erwinia aroideae

1973 ◽  
Vol 19 (9) ◽  
pp. 1153-1158 ◽  
Author(s):  
F. S. Liu ◽  
J. E. Zajic
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Oxygen Demand ◽  
Fermentation Medium ◽  
Optimum Level ◽  
Oxygen Requirement ◽  
Asparaginase Activity ◽  
Effect Of Oxygen

A variety of aeration and agitation conditions were used to investigate the oxygen demand of Erwinia aroideae for growth and L-asparaginase production in a 14-liter fermenter. Maximum L-asparaginase activity of 4.25 IU/ml was obtained when the fermentation medium was aerated at 0.5 volumes air per volume medium per minute and agitated at 500 rpm. However, the specific L-asparaginase activity was not affected significantly by the rate of oxygen transfer. In most instances the level of dissolved oxygen decreased to zero before harvesting. KLa rather than dissolved oxygen as measured during the fermentation cycle is a more satisfactory index to determine the oxygen requirement for cell growth and asparaginase production. The optimum level of KLa for L-asparaginase production was 0.98 min−1. However, a higher value of KLa of 1.2–1.9 min−1 was needed to achieve the highest growth.

DISTRIBUTION OF OXYGEN TRANSFER RATE IN STIRRED BIOREACTORS WITH SIMULATED BROTHS

2008 ◽  
Vol 7 (3) ◽  
pp. 199-211 ◽  
Author(s):  
Dan Cascaval ◽  
Anca-Irina Galaction ◽  
Stefanica Camarut ◽  
Radu Z. Tudose
Keyword(s):  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Stirred Bioreactors

scholarly journals Achieving Efficient and Stable Deammonification at LowTemperatures—Experimental and Modeling Studies

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3961
Author(s):  
Hussein Al-Hazmi ◽  
Xi Lu ◽  
Dominika Grubba ◽  
Joanna Majtacz ◽  
Przemysław Kowal ◽  
...  
Keyword(s):  
Sequencing Batch Reactor ◽  
Energy Savings ◽  
Batch Reactor ◽  
Phase Changes ◽  
Intermittent Aeration ◽  
Short Term ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
The Mathematical Model ◽  
Positive Effect

The short-term effects of temperature on deammonification sludge were evaluated in a laboratory-scale sequencing batch reactor (SBR). Mathematical modeling was used for further evaluations of different intermittent aeration strategies for achieving high and stable deammonification performance at decreasing temperatures. As for the biomass cultivated at high temperatures (e.g., 30 °C), a higher temperature dependency (the adjusted Arrhenius coefficient θ for 11–17 °C = 1.71 vs. θ for 17–30 °C = 1.12) on the specific anammox growth rates was found at lower temperatures (11–17 °C) in comparison with higher temperatures (17–30 °C). Further evaluations of recovering the nitrogen removal efficiency at decreasing temperatures with the mathematical model by modifying the intermittent aeration strategies (aeration frequency (F) and the ratio (R) between non-aerated (non-aer) phase and aerated (aer) phase durations) indicated that intermittent aeration with a prolonged non-aerated phase (e.g., R ≥ 4 regardless of F value) would help to maintain high and stable deammonification performance (~80%) at decreasing temperatures (14–22 °C). Extending the non-aerated phases (increasing R) and reducing the frequency (F) of off/on phase changes have a positive effect on increasing energy savings, leading to increasing interest in this method.

scholarly journals Two-Phase Flow Mass Transfer Analysis of Airlift Pump for Aquaculture Applications

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 226
Author(s):  
Rashal Abed ◽  
Mohamed M. Hussein ◽  
Wael H. Ahmed ◽  
Sherif Abdou
Keyword(s):  
Mass Transfer ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Two Phase Flow ◽  
Oxygen Transfer Rate ◽  
Flow Patterns ◽  
Oxygen Mass Transfer ◽  
Phase Flow ◽  
Two Phase ◽  
Airlift Pump

Airlift pumps can be used in the aquaculture industry to provide aeration while concurrently moving water utilizing the dynamics of two-phase flow in the pump riser. The oxygen mass transfer that occurs from the injected compressed air to the water in the aquaculture systems can be experimentally investigated to determine the pump aeration capabilities. The objective of this study is to evaluate the effects of various airflow rates as well as the injection methods on the oxygen transfer rate within a dual injector airlift pump system. Experiments were conducted using an airlift pump connected to a vertical pump riser within a recirculating system. Both two-phase flow patterns and the void fraction measurements were used to evaluate the dissolved oxygen mass transfer mechanism through the airlift pump. A dissolved oxygen (DO) sensor was used to determine the DO levels within the airlift pumping system at different operating conditions required by the pump. Flow visualization imaging and particle image velocimetry (PIV) measurements were performed in order to better understand the effects of the two-phase flow patterns on the aeration performance. It was found that the radial injection method reached the saturation point faster at lower airflow rates, whereas the axial method performed better as the airflow rates were increased. The standard oxygen transfer rate (SOTR) and standard aeration efficiency (SAE) were calculated and were found to strongly depend on the injection method as well as the two-phase flow patterns in the pump riser.

Oxygen Supply Method Using Gas-Permeable Film for Wastewater Treatment

1993 ◽  
Vol 28 (7) ◽  
pp. 243-250 ◽  
Author(s):  
Y. Suzuki ◽  
S. Miyahara ◽  
K. Takeishi
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Supply ◽  
Oxygen Transfer Rate ◽  
High Energy ◽  
High Rate ◽  
N Removal ◽  
High Energy Consumption

Gas-permeable film can separate air and water, and at the same time, let oxygen diffuse from the air to the water through the film. An oxygen supply method using this film was investigated for the purpose of reducing energy consumption for wastewater treatment. The oxygen transfer rate was measured for the cases with or without biofilm, which proved the high rate of oxygen transfer in the case with nitrifying biofilm which performed nitrification. When the Gas-permeable film with nitrifying biofilm was applied to the treatment of wastewater, denitrifying biofilm formed on the nitrifying biofilm, and simultaneous nitrification and denitrification occurred, resulting in the high rate of organic matter and T-N removal (7 gTOC/m2/d and 4 gT-N/m2/d, respectively). However, periodic sloughing of the denitrifying biofilm was needed to keep the oxygen transfer rate high. Energy consumption of the process using the film in the form of tubes was estimated to be less than 40% of that of the activated sludge process.

Study the effect of recycled pressurized air on oxygen transfer design parameters in sequencing batch reactor technology

2016 ◽  
Vol 31 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Hesham M. Elkaramany ◽  
Amro A. Elbaz ◽  
Amal N. Mohamed ◽  
Alhassan H. Sakr
Keyword(s):  
Oxygen Transfer ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Design Parameters ◽  
Reactor Technology

Flow Mixing Enhancement from Balloon Pulsations in an Intravenous Oxygenator

2004 ◽  
Vol 127 (3) ◽  
pp. 400-415 ◽  
Author(s):  
Amador M. Guzmán ◽  
Rodrigo A. Escobar ◽  
Cristina H. Amon
Keyword(s):  
Numerical Simulations ◽  
Oxygen Transfer ◽  
Fiber Bundle ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Three Dimensional ◽  
Time Dependent ◽  
Fiber Placement ◽  
Flow Mixing ◽  
Dependent Flow

Computational investigations of flow mixing and oxygen transfer characteristics in an intravenous membrane oxygenator (IMO) are performed by direct numerical simulations of the conservation of mass, momentum, and species equations. Three-dimensional computational models are developed to investigate flow-mixing and oxygen-transfer characteristics for stationary and pulsating balloons, using the spectral element method. For a stationary balloon, the effect of the fiber placement within the fiber bundle and the number of fiber rings is investigated. In a pulsating balloon, the flow mixing characteristics are determined and the oxygen transfer rate is evaluated. For a stationary balloon, numerical simulations show two well-defined flow patterns that depend on the region of the IMO device. Successive increases of the Reynolds number raise the longitudinal velocity without creating secondary flow. This characteristic is not affected by staggered or non-staggered fiber placement within the fiber bundle. For a pulsating balloon, the flow mixing is enhanced by generating a three-dimensional time-dependent flow characterized by oscillatory radial, pulsatile longitudinal, and both oscillatory and random tangential velocities. This three-dimensional flow increases the flow mixing due to an active time-dependent secondary flow, particularly around the fibers. Analytical models show the fiber bundle placement effect on the pressure gradient and flow pattern. The oxygen transport from the fiber surface to the mean flow is due to a dominant radial diffusion mechanism, for the stationary balloon. The oxygen transfer rate reaches an asymptotic behavior at relatively low Reynolds numbers. For a pulsating balloon, the time-dependent oxygen-concentration field resembles the oscillatory and wavy nature of the time-dependent flow. Sherwood number evaluations demonstrate that balloon pulsations enhance the oxygen transfer rate, even for smaller flow rates.

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