Alpha correction factors for static aerators and fine bubble diffusers used in municipal facultative aerated lagoons

1998 ◽  
Vol 38 (3) ◽  
pp. 79-85 ◽  
Author(s):  
C. Asselin ◽  
Y. Comeau ◽  
Q. A. Ton-That
Keyword(s):  
Mass Transfer ◽  
Correction Factor ◽  
Process Water ◽  
Oxygen Mass Transfer ◽  
Clean Water ◽  
Correction Factors ◽  
Mixed Liquor ◽  
Fine Bubble ◽  
Steel Tank ◽  
Bubble Diffusers

The alpha correction factor (KLa process water/KLa clean water; where KLa is the volumetric oxygen mass transfer coefficient) was evaluated for 4 kinds of static aerators and 2 kinds of fine bubble diffusers used in municipal facultative aerated lagoons. For this purpose, a 40 m3 steel tank was filled (3.1 m side water depth) with clean or process water. The process water consisted of “mixed liquor” from a municipal facultative aerated lagoon divided into a cascade of four identical basins that were 3.5 m deep. Results showed that in the last three basins, the alpha correction factors were relatively high, being between 0.85 to 0.95 for any type of aeration device. In the first lagoon, however, the alpha correction factors were between 0.70 and 0.90 for static aerators and about 0.70 for fine bubble diffusers. Furthermore, at the inlet of the first basin, the alpha factor was as low as 0.59 for a static aerator and 0.26 for a fine bubble diffuser, due to the composition of the “mixed liquor”. It was shown that the alpha correction factor that should be used for the design of aeration systems for facultative aerated lagoons should be lower in the first basin of a series of basins and could be higher than 0.85 for the downstream basins.

Effects of surfactant contamination on oxygen mass transfer in fine bubble aeration process

2013 ◽  
Vol 30 (9) ◽  
pp. 1741-1746 ◽  
Author(s):  
Xulu Chen ◽  
Guo-hua Liu ◽  
Haitao Fan ◽  
Meidi Li ◽  
Tao Luo ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Oxygen Mass Transfer ◽  
Fine Bubble ◽  
Aeration Process

scholarly journals Three decades of oxygen transfer tests in clean water in a pilot scale test tank with fine-bubble diffusers and the resulting conclusions for WWTP operation

2020 ◽  
Vol 15 (4) ◽  
pp. 910-920
Author(s):  
J. Behnisch ◽  
M. Schwarz ◽  
M. Wagner
Keyword(s):  
Oxygen Transfer ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Pilot Scale ◽  
Transfer Efficiency ◽  
Clean Water ◽  
Test Tank ◽  
Fine Bubble ◽  
Oxygen Transfer Efficiency ◽  
Bubble Diffusers

Abstract We summarized the experience from three decades of oxygen transfer testing and aeration research at the Technical University of Darmstadt to validate the oxygen transfer efficiency of modern fine-bubble diffusers. A total of 306 oxygen transfer tests in clean water of 65 different fine-bubble diffusers, carried out in the same test tank under identical test conditions, were analysed and compared with previous results. As a result, we could show that the performance of fine-bubble aeration systems has increased by 17% over the last three decades. Therefore, modern well-designed and operated aeration systems can achieve specific standard oxygen transfer efficiency (SSOTE) values between 8.5 and 9.8% · m−1. Additionally, a comparison of various diffuser types and diffuser densities was done. Based on the new results, an exemplary cost/benefit analysis for a 100,000 PE WWTP shows the calculation of an optimized diffuser density with respect to investment and operating costs.

An assessment of oxygen transfer efficiency in a gas permeable hollow fibre membrane biological reactor

2010 ◽  
Vol 61 (5) ◽  
pp. 1165-1171 ◽  
Author(s):  
G. Soreanu ◽  
L. Lishman ◽  
S. Dunlop ◽  
H. Behmann ◽  
P. Seto
Keyword(s):  
Mass Transfer ◽  
Chemical Reaction ◽  
Oxygen Transfer ◽  
Membrane Surface ◽  
Treatment Plant ◽  
Hollow Fibre ◽  
Transfer Efficiency ◽  
Fine Bubble ◽  
Oxygen Transfer Efficiency ◽  
Bubble Diffusers

The clean water oxygen transfer efficiency (OTE) of a full scale non-porous hollow fibre gas permeable (GP) membrane (surface area of 500 m2) was evaluated at inlet air pressures of 1.2, 1.4, and 1.8 atm using two established testing methods. To form a basis of comparison with traditional aeration technologies, additional testing was done with conventional aerators (fine bubble and coarse bubble diffusers) replacing the GP membrane. OTE can be established based on the re-aeration of deoxygenated water or by monitoring the catalytic oxidation of a sodium sulphite (Na2SO3) solution. In this study, OTE values determined by sulphite oxidation (SOTES) were consistently higher than those established during re-aeration (SOTER) suggesting that the chemical reaction was enhancing the mass transfer. The chemical reaction was sufficiently fast in the case of the GP membrane, that the gas phase limited the mass transfer. The GP membrane operating at 1.2 atm had a SOTES of 70.6% and a SOTER of 52.2%. SOTER for the coarse bubble and fine bubble diffusers were 3.8% and 23.6%, respectively. This is comparable to the manufacturer's values, corrected for depth of 3.4% and 18.3%, respectively. Particularly, the derived OTE values were used to evaluate differences in energy consumption for a conventional treatment plant achieving carbon removal and nitrification. This analysis highlights the potential energy efficiency of GP membranes, which could be considered for the design of the membrane modules.

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.

Influence of pluronic F68 on oxygen mass transfer

2013 ◽  
Vol 29 (5) ◽  
pp. 1278-1288 ◽  
Author(s):  
Christian Sieblist ◽  
Marco Jenzsch ◽  
Michael Pohlscheidt
Keyword(s):  
Mass Transfer ◽  
Oxygen Mass Transfer ◽  
Pluronic F68

Energy saving in activated sludge plants by the use of more efficient fine bubble diffusers

2010 ◽  
Vol 24 (1) ◽  
pp. 58-64 ◽  
Author(s):  
Martin Jolly ◽  
Steve Green ◽  
Cindy Wallis-Lage ◽  
Annelle Buchanan
Keyword(s):  
Activated Sludge ◽  
Energy Saving ◽  
Fine Bubble ◽  
Bubble Diffusers
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