Evaluation of the impact of dissolved oxygen concentration on biofilm microbial community in sequencing batch biofilm reactor

2018 ◽  
Vol 125 (5) ◽  
pp. 532-542 ◽  
Author(s):  
Jingyin Wang ◽  
Hongwei Rong ◽  
Chaosheng Zhang
2006 ◽  
Vol 41 (5) ◽  
pp. 1165-1172 ◽  
Author(s):  
Byung-Chol Ma ◽  
Yu-Na Lee ◽  
Jong-Sang Park ◽  
Chung-Hak Lee ◽  
Sang-Ho Lee ◽  
...  

Author(s):  
Mario Enrique Rueda ◽  
José Ernesto Mancera P.

With the purpose of assessing the impact generated by the use of an artisanal fishing method populary called "boliche", in the tropical coastal lagoon Ciénaga Grande de Santa Marta, different aspects were quantified; being one of them designed to analyze some physical-chemical alterations of the water column, produced during the fishing operations. The dissolved oxygen concentration, water transparency and seston composition and concentration, before and after of 70 boliche's thrusts were determinated. The results showthat fishing operations generate some momentary changes of little repercution to the ecosystem, such as particle resuspention principally inorganic an increase in seston concentration and a consequen water column transparency decrease. The dissolved oxygen concentration does not show appreciable alteration.


1992 ◽  
Vol 26 (7-8) ◽  
pp. 1769-1778 ◽  
Author(s):  
S.-I. Lee ◽  
B. Koopman ◽  
E. P. Lincoln

Combined chemical flocculation and autoflotation were examined using pilot scale process with chitosan and alum as flocculants. Positive correlation was observed between dissolved oxygen concentration and rise rate. Rise rate depended entirely on the autoflotation parameters: mixing intensity, retention time, and flocculant contact time. Also, rise rate was influenced by the type of flocculant used. The maximum rise rate with alum was observed to be 70 m/h, whereas that with chitosan was approximately 420 m/h. The efficiency of the flocculation-autoflotation process was superior to that of the flocculation-sedimentation process.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li Chaoyue ◽  
Feng Shiyu ◽  
Xu Lei ◽  
Peng Xiaotian ◽  
Yan Yan

AbstractDissolved oxygen evolving from aviation fuel leads to an increase in the oxygen concentration in an inert aircraft fuel tank ullage that may increase the flammability of the tank. Aviation fuel scrubbing with nitrogen-enriched air (NEA) can largely reduce the amount of dissolved oxygen and counteract the adverse effect of oxygen evolution. The gas–liquid mass transfer characteristics of aviation fuel scrubbing are investigated using the computational fluid dynamics method, which is verified experimentally. The effects of the NEA bubble diameter, NEA superficial velocity and fuel load on oxygen transfer between NEA and aviation fuel are discussed. Findings from this work indicate that the descent rate of the average dissolved oxygen concentration, gas holdup distribution and volumetric mass transfer coefficient increase with increasing NEA superficial velocity but decrease with increasing bubble diameter and fuel load. When the bubble diameter varies from 1 to 4 mm, the maximum change of descent rate of dissolved oxygen concentration is 18.46%, the gas holdup is 8.73%, the oxygen volumetric mass transfer coefficient is 81.45%. When the NEA superficial velocities varies from 0.04 to 0.10 m/s, the maximum change of descent rate of dissolved oxygen concentration is 146.77%, the gas holdup is 77.14%, the oxygen volumetric mass transfer coefficient is 175.38%. When the fuel load varies from 35 to 80%, the maximum change of descent rate of dissolved oxygen concentration is 21.15%, the gas holdup is 49.54%, the oxygen volumetric mass transfer coefficient is 44.57%. These results provide a better understanding of the gas and liquid mass transfer characteristics of aviation fuel scrubbing in aircraft fuel tanks and can promote the optimal design of fuel scrubbing inerting systems.


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