Diffused aeration systems from theory to design

1978 ◽  
Vol 5 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Jatinder K. Bewtra ◽  
Donald S. Mavinic
Keyword(s):  
Oxygen Transfer ◽  
Climatic Conditions ◽  
Air Bubbles ◽  
Cold Regions ◽  
Surface Aeration ◽  
Conventional Activated Sludge ◽  
Aeration System ◽  
Tank Geometry ◽  
Counter Current ◽  
Mechanical Surface

Aeration has been used successfully in northern Canada and other cold regions for treating domestic and industrial waste waters by aerated lagoons, extended aeration package units and conventional activated sludge plants. Many of these installations used diffused aeration because this system has shown several advantages over mechanical surface aeration. The advantages of using diffused aeration in cold regions for oxygenation as well as for mixing are discussed in this paper.The parameters affecting the efficiency of oxygen transfer and the mixing of the tank contents are identified and the influence of varying these operating parameters on the performance of diffused aeration systems under cold climatic conditions is discussed. Equations showing the influence of temperature, airflow rates, submergence and tank geometry on the overall oxygen transfer coefficient are presented.A process of aeration, employing counter-current flow of air bubbles and waste water, is shown to result in increased contact time and therefore higher oxygenation efficiencies. A typical example for designing a diffused aeration system in cold regions has been worked out.

scholarly journals Under Ice Water Movements Induced by Mechanical surface Aeration and Air Injection

2001 ◽  
Vol 17 (4) ◽  
pp. 263-287 ◽  
Author(s):  
Theron G. Miller ◽  
W. C. Mackay ◽  
David T. Walty
Keyword(s):  
Air Injection ◽  
Surface Aeration ◽  
Ice Water ◽  
Mechanical Surface

Study of the Oxygen Transfer Efficiencies in the Different Methods Used in the Technique of Hypolimnetic Aeration

2012 ◽  
Vol 452-453 ◽  
pp. 1014-1019 ◽  
Author(s):  
Gafsi Mostefa ◽  
Kettab Ahmed ◽  
Abdelkader Djehiche
Keyword(s):  
Oxygen Transfer ◽  
Thermal Stratification ◽  
Cold Water ◽  
Negative Impact ◽  
Drinking Water Treatment ◽  
Oxygen Depletion ◽  
Bubble Plume ◽  
Water Treatment Process ◽  
Aeration System ◽  
Lakes And Reservoirs

Thermal stratification of lakes and reservoirs can result in substantial hypolimnetic oxygen depletion, which may have a negative impact on the cold-water fisheries, the drinking water treatment process, and water quality downstream of hydropower reservoirs. Several techniques of aeration are presented in this study, to describe their effectiveness in control of physical and chemical parameters, that compromising the balance ecological and the thermal stratification in water supplies. As a result, we demonstrate that the most efficient hypolimnetic aeration system is the bubble plume diffuser; although an accidental destratification may occur. In hypolimnetic aeration systems, the aeration system by bubble plume appears to be the most economic and perhaps the simplest among the systems used in Stanley lake (Colorado, U.S.A), even as other researches select Speece Cone aeration system, or the full airlift systems, or the TVA line diffuser. The purpose of this study is to show the oxygen transfer efficiencies in the different methods used in the technique of hypolimnetic aeration, and their effect on the preservation of the thermal stratification. As well, this study concentrate on the economic and technical sides associated to these aeration systems.

scholarly journals The Influence of Optic and Polarographic Dissolved Oxygen Sensors Estimating the Volumetric Oxygen Mass Transfer Coefficient (KLa)

2016 ◽  
Vol 10 (8) ◽  
pp. 142 ◽  
Author(s):  
Gustavo Andrés Baquero-Rodríguez ◽  
Jaime A. Lara-Borrero
Keyword(s):  
Mass Transfer ◽  
Wastewater Treatment ◽  
Dissolved Oxygen ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Oxygen Transfer ◽  
Airflow Rate ◽  
Oxygen Probe ◽  
Aeration System ◽  
Oxygen Measurement

Aeration is usually the most energy intensive part of the wastewater treatment process. Optimizing the aeration system is essential for reducing energy costs. Field tests oriented to estimate parameters related to oxygen transfer are a common approach to compare aeration systems. The aim of this research is to assess the effect of dissolved oxygen probe lag on oxygen transfer parameter estimation. Experimental procedures regarding to process automation and control were applied to quantify dissolved oxygen probe lag. We have measured oxygen transfer in clean water, under a wide range of conditions (airflow rate, diffuser characteristics and diffuser density), with optic and polarographic sensors for dissolved oxygen measurement. The oxygen transfer was measured as per ASCE Standard procedures. Nonparametric statistical tests were used to compare the estimated volumetric mass transfer coefficient KLa with different sensors. According to the results, there is not significant influence of the probe lag (also known as time constant) or probe characteristics on the parameters used to assess oxygen transfer efficiency. This fact has great relevance in common practice of aerobic process for wastewater treatment because dissolved oxygen monitoring is used as an input for decision making related to the energy optimization in the aeration system. Findings from these tests contradict previous studies which claim that lag time in polarographic sensors for the dissolved oxygen measurement can bias estimate KLa.

A control strategy for reducing aeration costs during low loading periods

2004 ◽  
Vol 50 (7) ◽  
pp. 61-68 ◽  
Author(s):  
C. Sahlmann ◽  
J.A. Libra ◽  
A. Schuchardt ◽  
U. Wiesmann ◽  
R. Gnirss
Keyword(s):  
Flow Rate ◽  
Control Strategy ◽  
Oxygen Transfer ◽  
Air Flow ◽  
Air Flow Rate ◽  
Transfer Rates ◽  
Diffuser Flow ◽  
Aeration System ◽  
Oxygen Transfer Efficiency ◽  
Biomass Activity

The efficiency of the aeration system in a full-scale activated sludge basin with 3 separately controlled aeration zones was improved for the low loading period in summer. The air flow rate to each aeration zone is currently regulated to hold a preset dissolved oxygen concentration (DO). Four different DO setpoint combinations were tested, each one for a one week period, using dynamic off-gas testing to measure the standardised oxygen transfer efficiency (αSOTE). As the DO setpoints were lowered, the total air flow rate to the basin decreased initially. A low DO in the first zones slowed biomass activity and pushed the load towards the end of the aeration basin. The relationship between αSOTE and the specific diffuser flow rate qD is different for each zone. In Zone 1 there was a strong decrease in αSOTE as qD increased, while Zones 2 and 3 were fairly independent of qD, Zone 2 at a higher level than Zone 3. Aeration costs were reduced by 15% for the most efficient combination. To achieve even more savings, a control strategy adjusting oxygen transfer rates over the aeration basin to the necessary oxygen transfer rates is suggested. It is based on changing the DO setpoints to reach the lowest total air flow rate while meeting the effluent requirements.

Evaluation of a Field-Scale Surface Aeration System in an Anaerobic Poultry Lagoon

2010 ◽  
Vol 26 (2) ◽  
pp. 307-318 ◽  
Author(s):  
S. Mukhtar ◽  
M. S. Borhan ◽  
S. Rahman ◽  
J. Zhu
Keyword(s):  
Field Scale ◽  
Surface Aeration ◽  
Aeration System ◽  
Scale Surface

Non-Conventional Technologies for the Manufacturing Systems Use in Biological Wastewater Treatment Process

2015 ◽  
Vol 809-810 ◽  
pp. 1573-1578
Author(s):  
Casen Panaitescu ◽  
Monica Emanuela Stoica ◽  
Ciner Fehiman
Keyword(s):  
Wastewater Treatment ◽  
Oxygen Transfer ◽  
Manufacturing Systems ◽  
Wastewater Treatment Plants ◽  
Design Parameters ◽  
Biological Wastewater Treatment ◽  
Wastewater Treatment Process ◽  
Aeration System ◽  
Treatment Technologies ◽  
And Performance

Manufacture of wastewater treatment technologies is an important issue due to the complexity of design parameters and performance. Biological wastewater treatment is a process in which the intensity of oxygen transfer into water is an issue that has been extensively studied but yet insufficiently resolved. The present paper aims to describe an aeration system developed by the author in the laboratory by means of non-conventional technologies, and subsequently implemented in refinery wastewater treatment plants. The aeration system takes the form of modules, which are equipped with a new type of membrane. The analysis of the system performance revealed that oxygen transfer was 62%, specific adsorption of oxygen was 37 % and the specific oxygen transfer was 7%/m. The advantages of this new system are as follows: compared to existing technologies there is a higher rate of oxygen transfer into water; longer life; there are no dead zones in the basin as a result of their location; possibility of operating on separate sections.

Study of a Non-Conventional Aeration System

1987 ◽  
Vol 19 (5-6) ◽  
pp. 869-876
Author(s):  
L. Raschid-Sally ◽  
M. Roustan ◽  
H. Roques ◽  
G. M. Faup
Keyword(s):  
Oxygen Transfer ◽  
Peclet Number ◽  
Péclet Number ◽  
Theoretical Approaches ◽  
Aeration System ◽  
Circulation Velocity ◽  
The Mean ◽  
Oxygen Transfer Capacity ◽  
Mean Circulation ◽  
Conventional Systems

A non-conventional aeration system for oxidation ditches using jets has been developed. The principle of this system is based on the separation of the 2 actions: aeration and circulation. It was concluded that the flow of the liquid in the channel can be successfully modelled using various theoretical approaches. The mean circulation velocity VC, the power dissipated P, and the Peclet number Pe are the 3 important parameters governing the circulation. The oxygen transfer capacity of the system has been studied and compares favourably with that of conventional systems. The advantage of such systems over conventional ones has been discussed.

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