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The overall volumetric oxygen transfer coefficient in high viscosity, alginate-rich media

BIOCHEMICAL ENGINEERING JOURNAL 2025年 215卷

作者： Noach, Matthew N. Pott, Robert W. M. Goosen, Neill J. Van Rensburg, Eugene Univ Stellenbosch Dept Chem Engn ZA-7600 Stellenbosch South Africa

Understanding the impact of alginate, or similar high-viscosity polymers, on the oxygen transfer in aerobic bioprocess is critical in bioprocess development. Further, in the case of alginate lyase production, it is common for the media to also include significant concentrations of NaCl, which alters the ionic strength and impacts K(L)a. The results show that in alginate containing media, as the concentration of alginate increases, the fluid viscosity increases, leading to the reduction in K(L)a. However, comparison of the water-air and water-alginate-air systems revealed that at increased agitation rates (i.e. > 200 rpm) the K(L)a is enhanced in the water-alginate-air system as compared to the water-air system. This enhancement of K(L)a was seen up to 10.5 g/L of alginate. We propose this is due to two competing effects. Under lower alginate concentration, the influence of NaCl on bubble size and formation properties enhanced K(L)a in comparison to the water-air system. However, an additional increase in alginate concentration resulted in the reduction of K(L)a as the effect of increased viscosity, which reduces the liquid phase mass transfer, became the dominant effect. These results suggest that for fermentation utilising viscous media, operating under lower alginate concentrations may prevent oxygenation issues. Furthermore, the observations made emphasise the need to consider additives such as NaCl in fermentation media when estimating K(L)a.

关键词： oxygen transfer coefficient Alginate-based bioprocesses Alginate lyase production Stirred bioreactor

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CONTINUOUS DETERMINATION OF oxygen-transfer coefficient WITH AN ONLINE RESPIRATION METER

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WATER SCIENCE AND TECHNOLOGY 1993年第7期28卷 63-69页

作者： KIM, CW SPANJERS, H KLAPWIJK, A WAGENINGEN UNIV AGR DEPT ENVIRONM TECHNOL6702 CC WAGENINGENNETHERLANDS

An on-line respiration meter was applied to measure the oxygen transfer coefficient (K(L)a) continuously in a completely mixed aeration tank. The uniqueness of this respiration meter lies in its ability to measure the actual respiration rate of activated sludge. The calculation of K(L)a can be carried out continuously with steady-state and discrete non-steady state equations using actual respiration rate and DO in the aeration tank. In an activated sludge pilot plant, the oxygen transfer coefficients were determined under constant and variable loading conditions using the above procedures. The relationship between K(L)a and air flow was found to be linear but dependent on the wastewater loading characteristic. Under variable loading conditions, the calculated DOs in the aeration tank using the obtained K(L)a's were more accurate than that using the K(L)a's estimated from the air flow rate function. The accuracy of separately assumed saturation DO in the activated sludge was confirmed from a linear relationship between DOs in the aeration tank and corresponding actual respiration rates at a constant K(L)a.

关键词： ACTIVATED SLUDGE RESPIRATION RATE oxygen transfer coefficient ONLINE RESPIRATION METER

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Water surface contacting cover system - the basic study for improving the oxygen transfer coefficient and the BOD removal capacity

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WATER RESEARCH 2005年第8期39卷 1553-1559页

作者： Kim, YK Ra, DG Sunchon Natl Univ Div Civil & Environm Engn Chungnam 540742 South Korea Jeonju Univ Ctr EM Res & Dev Jeonbuk 560759 South Korea

In order to construct an environmental aeration basin in a sewage treatment plant, the suggested novel aeration basin was examined for the oxygen transfer coefficient by using tap water on a lab-scale and pilot-scale. We called it water surface contacting cover system (WSCCS) that was installed with a cover plate on the wafer surface and a slant plate in aeration basin, compared to a standard aeration basin (SRAS, spiral roll aeration system). Finally, the novel basin could be compared by adopting the slant and cover plates into the actual sewage treatment plant (W x L x D (m) = 5.0 x 2.65 x 4.25, treatment capacity: 600 m(3) /d). As a result, only by adding a slant plate, the oxygen transfer coefficient (K(L)a) increased approximately by 15% more than that with a SRAS basin. And the slope of slant plate was optimized at 10 degrees. Additionally, in the WSCCS, the increasing efficiency of the oxygen transfer coefficient, affected only by the cover, was proved at about 25% on the labscale aeration basin and about 20% on the pilot plant. After all, the increasing effect of the oxygen transfer coefficient on WSCCS that was installed with the water contacting cover and the slant plate on standard aeration basin was proved to be above 35%. The distance between the air diffuser and the slant plate was 20-30 cm in the pilot-scale plant. As an effective factor for increasing the oxygen transfer rate, the width/depth ratio of aeration basin was proved to be 2. Through the short-term results of actual sewage treatment plant, it was known that BOD removal efficiency could be improved by about 3% by adopting tile WSCCS not but SRAS. (c) 2004 Published by Elsevier Ltd.

关键词： water surface contacting cover system spiral roll aeration system oxygen transfer coefficient aeration basin slant plate

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Effect of aeration and agitation rates and scale-up on oxygen transfer coefficient, k_La in exopolysaccharide production from Enterobacter cloacae WD7

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CARBOHYDRATE POLYMERS 2006年第2期66卷 216-228页

作者： Bandaiphet, C. Prasertsan, P. Prince Songkla Univ Fac Agro Ind Dept Ind Biotechnol Hat Yai 90112 Thailand

In the exopolysaccharide production from Enterobacter cloacae WD7 under aerobic fermentation, biopolymer yield increased with aeration and agitation rates increasing at pilot plant scale, but decreased when agitation increased at bench scale because of shear thinning character (from 3.07 to 2.28 g/g over the range 200-800 rpm). However, it increased with increase of aeration rate (from 2.79 to 3.07 g/g over the range 0.5-1.25 vvm, respectively). By a dynamic gassing-out technique, the effects of aeration rate, agitation rate, character and size of fermentor and its accessories on the volumetric oxygen transfer coefficient k(L)a were studied. Values of kLa in the exponential and stationary phases increased with aeration and agitation rates to 9.97 and 9.72 h(-1) in exponential and stationary phases at aeration rate 1.25 vvm of bench scale fermentation and 9.68 and 9.50 h(-1) in exponential and stationary phases at aeration rate 1.75 vvm of pilot plant scale fermentation, respectively. Scale-up in the pilot plant performed by 'k(L)a fixing', controlling the oxygen change in the fermentor broth by holding the kLa value to equal to the value obtained from small fermentor, resulted in a biopolymer yield of 3.20 g/g c.f. 3.07 g/g at bench scale. (c) 2006 Elsevier Ltd. All rights reserved.

关键词： biopolymer Enterobacter cloacae WD7 scale-up oxygen transfer coefficient k(L)a oxygen transfer rate, OTR oxygen uptake rate, OUR flow rheology

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SIMULTANEOUS DETERMINATION OF oxygen-UPTAKE RATE AND oxygen-transfer coefficient IN ACTIVATED-SLUDGE SYSTEM BY AN ONLINE METHOD

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WATER RESEARCH 1990年第6期24卷 725-732页

作者： SOLLFRANK, U GUJER, W SWISS FED INST WATER RESOURCES & WATER POLLUT CONT EAWAG CH-8600 DUBENDORF SWITZERLAND

A new on-line method for the measurement of oxygen uptake rate and oxygen transfer coefficient (kLaeff) in activated sludge systems is introduced. Based on mass balance equations for dissolved oxygen in the aeration basin and a parallel flow-through measuring chamber the system offers a high time resolution and is therefore, especially under dynamic process conditions, of great advantage compared to conventional measurements. The method has been tested and verified at a laboratory plant with variable process conditions, changing activities of microorganisms anc variation of loading using a microprocessor. The measurement allows advanced process control in activated sludge systems and may be used in a slightly modified form for a large number of further applications as far as the evaluation of kinetic process parameters or the operation with ion-selective electrodes.

关键词： activated sludge on-line measurement oxygen uptake rate oxygen transfer coefficient process control biological kinetics

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Effect of bio-carrier filling rate on oxygen transfer coefficient of different diffusers in MBBR process

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DESALINATION AND WATER TREATMENT 2016年第39期57卷 18234-18239页

作者： Sun, Lifeng Zhang, Feng Liu, Changqing Bi, Xuejun Cheng, Lihua Li, Shuai Liu, Ying Qiao, Zhong Qingdao Technol Univ Sch Comp Engn Qingdao 266033 Peoples R China Qingdao Technol Univ Sch Environm & Municipal Engn Qingdao 266033 Peoples R China Univ Michigan Sch Civil & Environm Engn Ann Arbor MI 48109 USA

This paper mainly discussed the effect of bio-carrier filling rate on the oxygen transfer coefficient of different diffusers in the MBBR process. The results show that bio-carriers could increase the oxygen transfer coefficients of the microporous diffusers both in clean water and in mixed liquor because of the shearing effect that created microbubbles and enhanced microscopic hydrodynamic flow regime of the reactor. Compared to the test without bio-carriers, dosing bio-carriers could increase the oxygen transfer coefficient of microporous membrane diffuser by 10.78% in clean water and 10.17% in mixed liquor. Dosing bio-carriers could increase the oxygen transfer coefficient of the campanulate corundum aerator and perforated pipe more than the microporous membrane diffuser. Compared to the control, dosing bio-carriers could increase the K-La of campanulate corundum aerator and perforated pipe diffuser by almost 13.40 and 17.74% in clean water, and 10.97 and 20.14% in mixed liquor, respectively.

关键词： Filling rate Diffuser oxygen transfer coefficient MBBR process

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ON THE METHODS FOR THE DETERMINATION OF THE oxygen-transfer coefficient IN MECHANICALLY AGITATED VESSELS

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CHEMICAL ENGINEERING COMMUNICATIONS 1990年第1期94卷 35-51页

作者： DENIS, A THIBAULT, J LEDUY, A UNIV LAVAL DEPT CHEM ENGNQUEBEC CITY G1K 7P4QUEBECCANADA

This paper reports on the determination of the overall oxygen transfer coefficient in mechanically agitated vessels. Many variants of the sulfite oxidation method are compared with the dynamic method. A new variant of the sulfite oxidation method, called the reaction time method, is proposed. Overall oxygen mass transfer coefficients were obtained with two probes having significantly different time constants and for various agitation levels. The advantages and disadvantages of the main methods used for the determination of the oxygen transfer coefficient are reviewed and discussed.

关键词： oxygen transfer coefficient KLa Sulfite method Mechanically agitated vessels

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THE EFFECTS OF THE oxygen-transfer coefficient AND SUBSTRATE CONCENTRATION ON THE XYLOSE FERMENTATION BY DEBARYOMYCES-HANSENII

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ARCHIVES OF MICROBIOLOGY 1991年第6期156卷 484-490页

作者： ROSEIRO, JC PEITO, MA GIRIO, FM AMARALCOLLACO, MT UNIDADE BIOTECNOL LISBOA DEPT TECNOL IND ALIMENTARESLAB NACL ENGN & TECHNOL INDR VALE FORMOSOP-1900 LISBONPORTUGAL

Relevant production of xylitol by Debaryomyces hansenii requires semiaerobic conditions since in aerobic conditions the accumulated reduced adenine dinucleotide coenzyme is fully reoxidized leading to the conversion of xylitol into xylulose. For oxygen transfer coefficient values from 0.24 to 1.88 min-1, in shake flasks experiments, biomass formation increased proportionally to the aeration rate as shown in the oxygen transfer coefficient and xylose concentration isoresponse contours. The metabolic products under study, xylitol and ethanol were mainly growth associated. However, for oxygen transfer coefficient above 0. 5 min-1 higher initial xylose concentration stimulated the rate of production of xylitol. This fact was less evident for ethanol production. The direct relationship between increased biomass and products formation rate, indicated that the experimental domain in respect to the aeration rate was below the threshold level before the decreasing in metabolic production rates reported in literature for xylose-fermenting yeasts. The fact that ethanol was produced, albeit in low levels, throughout the experimental design indicated that the semiaerobic conditions were always attained. Debaryomyces hansenii showed to be an important xylitol producer exhibiting a xylitol/ethanol ratio above four and a carbon conversion of 54% for xylitol.

关键词： D-XYLOSE FERMENTATION DEBARYOMYCES-HANSENII XYLOSE-FERMENTING YEASTS oxygen transfer coefficient XYLITOL ETHANOL DOEHLERT EXPERIMENTAL DESIGN

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Boosting productivity of heterotrophic microalgae by efficient control of the oxygen transfer coefficient using a microbubble sparger

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ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS 2019年 41卷 101474-000页

作者： Ju, Jung-Hyun Oh, Beak-Rock Ko, Dong-Jin Heo, Sun-Yeon Lee, Jong-Jea Kim, Young-Min Yang, KwonSeok Seo, Jeong-Woo Hong, Won-Kyung Kim, Chul-Ho KRIBB Microbial Biotechnol Res Ctr Jeonbuk Branch Inst Jeongeup 56212 Jeonbuk South Korea Chonnam Natl Univ Dept Food Sci & Technol Gwangju 61186 South Korea Chonnam Natl Univ Funct Food Res Ctr Gwangju 61186 South Korea Chonbuk Natl Univ Korea Zoonosis Res Inst Iksan 54531 Jeonbuk South Korea Aerowaters Co LTD Ulsan 44905 South Korea

We isolated and characterized an oleaginous Thraustochytrid microalga. Based on 18 s rRNA sequencing, we classified this strain as Schizochytrium sp. SH103. Growth of these cells in a 5 L fermentor with a microbubble-type sparger (MTS) efficiently increased the oxygen transfer coefficient (OTC), while inducing only low external stress. For fermentation under conditions of low agitation (100 rpm) and aeration (3 L/min), the OTC was 8.6-fold higher using a MTS than a general type sparger (GTS). Under these same conditions, dry cell weight (DCW) productivity (0.54 vs. 1.26 g/L.h) and total lipid productivity (0.29 vs. 0.61 g/L.h) were each about 2.2-fold higher using a MTS than a GTS. Under conditions that optimized the OTC in a MTS fermentor (876 h(-1)), DCW productivity, total lipid productivity and DHA productivity were each 1.3-fold greater than non-optimized condition. Fed-batch fermentation experiments indicated the maximal DCW was 100.6 g/L at 48 h, maximal DCW productivity was 2.1 g/L.h, maximal lipid content was 48.6 g/L at 48 h, and lipid productivity was 1.0 g/L.h. Additionally, the results of experiments using a 50 L MTS fermentor (96.0 g/L DCW and 44.3 g/L total lipids at 48 h) were similar to those using the 5 L fermentor. Our results suggest that use of a MTS may help to achieve the efficient fermentation of heterotrophic microalgae for high cell densities.

关键词： Schizochytrium sp. Bio-oil Microbubble oxygen transfer coefficient

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Effect of Filling Rate on oxygen transfer coefficient of Different Diffusers in MBBR Process

Effect of Filling Rate on Oxygen Transfer Coefficient of Dif...

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2015(第十届)青岛国际脱盐大会暨全国冶金节水与废水利用技术研讨会

作者： Sun Lifeng Zhang Feng Liu Changqing Li Shuai Liu Ying School of Computer Engineering Qingdao Technological UniversityQingdao 266033 School of Environmental and Municipal Engineering Qingdao Technological UniversityQingdao 266033

This paper mainly discussed the effect of filling rate on oxygen transfer coefficient of different diffusers in MBBR *** result shows, because of the cutting action on micro bubbles and improving for microscopic hydrodynamic flow regime of reactor, the fillers can increase oxygen transfer coefficient of micro porous membrane diffuser whether in clean water or in mixed liquor *** to the blank test without fillers, dosing filler can increase oxygen transfer coefficient of micro porous membrane diffuser at most 10.78% in clean water test and 10.17% in mixed liquor *** filler can increase oxygen transfer coefficient of campanulate corundum aerator and perforated pipe more than micro porous membrane *** to the blank test, dosing filler can increase KLa of campanulate corundum aerator and perforated pipe diffuser at most 13.40%, 17.74% in clean water test and 10.97%, 20.14% in mixed liquor test respectively.

关键词： filling rate diffuser oxygen transfer coefficient MBBR process

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