Analysis of Oxygen Transfer and Dissolved Oxygen Concentration Measurement Tests in a Wastewater Treatment Plant

2014 ◽  
Vol 656 ◽  
pp. 486-494
Author(s):  
Marius Daniel Roman ◽  
Raluca Andreea Felseghi
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Oxygen Transfer ◽  
Treatment Plant ◽  
Dissolved Oxygen Concentration ◽  
Coverage Area ◽  
Type Size ◽  
Oxygen Efficiency ◽  
Oxygen Transfer Capacity ◽  
Tank Geometry

The efficiency of oxygen transfer depends on many factors including the type, size and shape of diffusers and the tank geometry. In this paper, the effect of the depth of water in the tank and the extension of coverage area of diffusers on each of oxygen transfer capacity, efficiency and dissolved oxygen concentration is tested. Experimental procedure is adopted to evaluate the effect of dissolved oxygen concentration. The results of the case study showed that, both the depth of water and the extent of coverage area of diffuser had a significant effect on the tested parameters. The values of oxygen transfer capacity was 76,7 kg O2/h and oxygen efficiency (without agitation): 5,3 kg O2/h, oxygen efficiency (with agitation): 4,2 kg O2/h.

Prediction of dissolved oxygen concentration along sanitary sewers

1996 ◽  
Vol 34 (5-6) ◽  
pp. 525-532 ◽  
Author(s):  
J. Saldanha Matos ◽  
E. Ribeiro de Sousa
Keyword(s):  
Mathematical Model ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Oxygen Transfer ◽  
Oxygen Balance ◽  
Dissolved Oxygen Concentration ◽  
Empirical Expression ◽  
Slime Layer ◽  
Sanitary Sewers ◽  
The Mathematical Model

The oxygen balance in wastewater collection systems is important in respect to the degree of biological oxidation that occurs within the stream and in respect to the control of septicity and its effects. In this paper, a simple mathematical model is presented, in order to predict dissolved oxygen concentration profiles along sanitary sewers. The mathematical model was developed based on an analytical solution of the simple differential equation of dissolved oxygen balance in sewers, and includes an empirical expression for prediction of dissolved oxygen transfer to the slime layer on the pipe walls. Because the factors controlling dissolved oxygen balance in sewers are so complex, it would be unrealistic to expect, that with this rather simple model, dissolved oxygen concentrations can be accurately predicted. Nevertheless, it is reasonable to suppose that the predictions may be adequate for some design and operation purposes.

scholarly journals Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 516 ◽  
Author(s):  
Rauno Lust ◽  
Jaak Nerut ◽  
Kuno Kasak ◽  
Ülo Mander
Keyword(s):  
Organic Carbon ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Power Efficiency ◽  
Municipal Wastewater ◽  
Nitrate Removal ◽  
Treatment Plant ◽  
Municipal Wastewater Treatment ◽  
Dissolved Oxygen Concentration ◽  
Organic Carbon Concentration

Assessments of groundwater aquifers made around the world show that in many cases, nitrate concentrations exceed the safe drinking water threshold. This study assessed how bioelectrochemical systems could be used to enhance nitrate removal from waters with low organic carbon concentrations. A two-chamber microbial electrosynthesis cell (MES) was constructed and operated for 45 days with inoculum that was taken from a municipal wastewater treatment plant. A study showed that MES can be used to enhance nitrate removal efficiency from 3.66% day−1 in a control reactor to 8.54% day−1 in the MES reactor, if a cathode is able to act as an electron donor for autotrophic denitrifying bacteria or there is reducing oxygen in a cathodic chamber to favor denitrification. In the MES, greenhouse gas emissions were also lower compared to the control. Nitrous oxide average fluxes were −639.59 and −9.15 µg N m−2 h−1 for the MES and control, respectively, and the average carbon dioxide fluxes were −5.28 and 43.80 mg C m−2 h−1, respectively. The current density correlated significantly with the dissolved oxygen concentration, indicating that it is essential to keep the dissolved oxygen concentration in the cathode chamber as low as possible, not only to suppress oxygen’s inhibiting effect on denitrification but also to achieve better power efficiency.

Effect of Design Parameters on Air Entrainment and Oxygen Transfer of Central-Driven Ejector

2014 ◽  
Vol 960-961 ◽  
pp. 528-533
Author(s):  
Dong Jun Kim ◽  
Hui Wei Du ◽  
Kyuho Kim ◽  
Lu Peng ◽  
Heicheon Yang
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Oxygen Transfer ◽  
Air Entrainment ◽  
Nozzle Diameter ◽  
Tube Length ◽  
Design Parameters ◽  
Dissolved Oxygen Concentration ◽  
Entrainment Ratio ◽  
Diffuser Angle

The objective of this study is to investigate the air entrainment and oxygen transfer characteristics of central-driven ejector with various ejector design parameters. The ejector design parameters are primary nozzle diameter, mixing tube length and diffuser angle. The entrainment ratio decreased with the primary nozzle diameter and diffuser angle, while the ratio increased with the mixing tube length. The trend of dissolved oxygen concentration with the diffuser angle and mixing tube length is equal to the result of entrainment ratio, however, the trend with the primary nozzle diameter is different to the result of entrainment ratio.

Effect of Physicochemical Variables on Algal Autoflotation

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1769-1778 ◽  
Author(s):  
S.-I. Lee ◽  
B. Koopman ◽  
E. P. Lincoln
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Retention Time ◽  
Contact Time ◽  
Pilot Scale ◽  
Dissolved Oxygen Concentration ◽  
Physicochemical Variables ◽  
Rise Rate ◽  
Mixing Intensity ◽  
Maximum Rise

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.

scholarly journals Gas–liquid mass transfer characteristics of aviation fuel scrubbing in an aircraft fuel tank

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li Chaoyue ◽  
Feng Shiyu ◽  
Xu Lei ◽  
Peng Xiaotian ◽  
Yan Yan
Keyword(s):  
Mass Transfer ◽  
Dissolved Oxygen ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Oxygen Concentration ◽  
Gas Holdup ◽  
Aviation Fuel ◽  
Volumetric Mass Transfer Coefficient ◽  
Dissolved Oxygen Concentration ◽  
Liquid Mass Transfer

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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