Operational results and experience with submerged fixed-film reactors in the pretreatment of industrial effluents

2000 ◽  
Vol 41 (4-5) ◽  
pp. 453-459 ◽  
Author(s):  
S. Schlegel ◽  
B. Teichgräber
Keyword(s):  
Activated Sludge ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Industrial Effluents ◽  
Operating Costs ◽  
Activated Sludge Process ◽  
Structural Requirements ◽  
Fixed Film ◽  
Film Reactor

Submerged fixed-film reactors are ideal for the pretreatment of industrial effluents. The advantages lie not only in the investment costs, but also in the operating costs. The pretreatment plants can be subject to higher loads than are possible with the activated sludge process. Consequently, considerably less space is required. And, last but not least, it is also possible to treat normally non-degradable industrial effluents. The prerequisites are that system-related general structural requirements are fulfilled and suitable materials are used for the fixed-film reactor. They also offer considerable advantages in terms of operation compared to the activated sludge process, since both a higher oxygen transfer rate and yield are achieved, less sludge is produced and fewer personnel are required. All in all, the upstream submerged fixed-film reactor has proven to be an extremely reliable process, requiring little maintenance, that can cope, to a far-reaching degree, with load fluctuations of all types and reduce these. As a result, the operation of downstream treatment stages is also stabilized.

Oxygen transfer in activated sludge – new insights and potentials for cost saving

2011 ◽  
Vol 63 (12) ◽  
pp. 3034-3038 ◽  
Author(s):  
J. Henkel ◽  
P. Cornel ◽  
M. Wagner
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Organic Load ◽  
Current Opinion ◽  
Conventional Activated Sludge ◽  
Current State ◽  
Activated Sludge Systems

The α-factor has the greatest impact on the calculation of the required standard oxygen transfer rate (SOTR) in activated sludge systems equipped with submerged aeration systems. Knowing the dependencies of the α-factor leads to a better design of the aeration devices and, consequently, to a more efficient use of aeration energy. Applying the current state of knowledge about oxygen transfer leads to the conclusion that, in contrast to current opinion, simultaneous aerobic stabilization requires the same SOTR as conventional activated sludge systems with advanced nutrient removal, even though a higher organic load is degraded.

Design of aeration systems in activated sludge plants at different wastewater temperatures

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
T. Guenkel ◽  
M. Wagner
Keyword(s):  
Oxygen Uptake ◽  
Activated Sludge ◽  
Uptake Rate ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Uptake Rate ◽  
Oxygen Transfer Rate ◽  
Decisive Factor ◽  
Volume Increase ◽  
The Impact

The standard oxygen transfer rate (SOTR) is the decisive factor in the dimensioning of activated sludge plants. It depends on the required oxygen uptake rate (OUR) by microorganisms. The dependencies of the SOTR and OUR on the wastewater temperature (range 5–30 °C) are discussed. It is shown that the absolute values of the SOTR depend only slightly on the wastewater temperature, while the specific values, in relation to the aerated tank volume, increase considerably as a function of the wastewater temperature. Within this context, the decisive dimensioning temperature is discussed. In addition, two design approaches for determining the SOTR, temperature-dependant and temperature-independent, are presented and compared, showing the impact of the water dependency. Finally, the sensitivity of the decisive factors for determining the SOTR is discussed, particularly addressing the influence of the α-value.

Evaluation of biological technologies for wastewater treatment in the pharmaceutical industry

1995 ◽  
Vol 32 (11) ◽  
pp. 13-20 ◽  
Author(s):  
F. A. El-Gohary ◽  
S. I. Abou-Elela ◽  
H. I. Aly
Keyword(s):  
Activated Sludge ◽  
Treatment Options ◽  
Feasibility Studies ◽  
Activated Sludge Process ◽  
Oil And Grease ◽  
Chemical Company ◽  
Treated Effluent ◽  
First Choice ◽  
Fixed Film ◽  
Film Reactor

Wastewater from a pharmaceutical and chemical company provides the material of this study. The company produces drugs, diuretics, laboratory chemicals and others. The company is located 30 km north of Cairo, and discharges both industrial (1050 m3/d) and human wastewater (8400 m3/d) without treatment into a near-by evaporation pond. Reduction of pollutants in the wastewater down to permissible concentrations is necessary for the protection of ground water and the environment. Analysis of the combined wastes indicated that it is very acidic and contains high concentrations of organic compounds and total solids. Combined wastes were subjected to different treatment processes for final disposal into surface water, or reuse for irrigation purposes. Biological treatment of the combined wastes was carried out using both batch and continuous flow systems. The biological treatments included activated sludge process, fixed film reactor, and fixed film reactor followed by activated sludge process. Technical feasibility studies indicated that good quality effluent could be obtained using either extended aeration (20 hr aeration) or a fixed film reactor followed by activated sludge (11 hr detention time). Residual BOD5, COD, oil and grease concentrations in the treated effluent were complying with the National Regularity Standards. When constructional cost was considered, extended aeration was the first choice. Engineering designs of the proposed treatment options are included.

DISTRIBUTION OF OXYGEN TRANSFER RATE IN STIRRED BIOREACTORS WITH SIMULATED BROTHS

2008 ◽  
Vol 7 (3) ◽  
pp. 199-211 ◽  
Author(s):  
Dan Cascaval ◽  
Anca-Irina Galaction ◽  
Stefanica Camarut ◽  
Radu Z. Tudose
Keyword(s):  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Stirred Bioreactors

Estimation of oxygen transfer rate in sequencing batch reactor

1996 ◽  
Vol 34 (3-4) ◽  
pp. 413-420
Author(s):  
Y. C. Liao ◽  
D. J. Lee
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Oxygen Transfer Rate ◽  
Intermittent Aeration ◽  
Transient Effects ◽  
Operational Parameters ◽  
Transient Model

Transient model of oxygen transfer rate in a sequencing batch reactor is derived and solved numerically. The dissolved oxygen response under several conditions is analyzed. Effects of operational parameters and liquid bath height are studied. When with short, intermittent aeration periods, the transient effects on oxygen transfer rate may be substantial and should be taken into considerations. An example considering bioreaction is also given.

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.

Oxygen Supply Method Using Gas-Permeable Film for Wastewater Treatment

1993 ◽  
Vol 28 (7) ◽  
pp. 243-250 ◽  
Author(s):  
Y. Suzuki ◽  
S. Miyahara ◽  
K. Takeishi
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Supply ◽  
Oxygen Transfer Rate ◽  
High Energy ◽  
High Rate ◽  
N Removal ◽  
High Energy Consumption

Gas-permeable film can separate air and water, and at the same time, let oxygen diffuse from the air to the water through the film. An oxygen supply method using this film was investigated for the purpose of reducing energy consumption for wastewater treatment. The oxygen transfer rate was measured for the cases with or without biofilm, which proved the high rate of oxygen transfer in the case with nitrifying biofilm which performed nitrification. When the Gas-permeable film with nitrifying biofilm was applied to the treatment of wastewater, denitrifying biofilm formed on the nitrifying biofilm, and simultaneous nitrification and denitrification occurred, resulting in the high rate of organic matter and T-N removal (7 gTOC/m2/d and 4 gT-N/m2/d, respectively). However, periodic sloughing of the denitrifying biofilm was needed to keep the oxygen transfer rate high. Energy consumption of the process using the film in the form of tubes was estimated to be less than 40% of that of the activated sludge process.

Dynamic modeling of nitrogen removal for a three-stage integrated fixed-film activated sludge process treating municipal wastewater

2017 ◽  
Vol 41 (2) ◽  
pp. 237-247 ◽  
Author(s):  
Paul Moretti ◽  
Jean-Marc Choubert ◽  
Jean-Pierre Canler ◽  
Pierre Buffière ◽  
Olivier Pétrimaux ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Dynamic Modeling ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Activated Sludge Process ◽  
Fixed Film
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