An experimental study of nozzle diameters, aeration depths and angles on standard aeration efficiency (SAE) in a venturi aerator

2009 ◽  
Vol 4 (3) ◽  
Author(s):  
M.R. Ghomi ◽  
M. Sohrabnejad ◽  
M. R. Ovissipour
Keyword(s):  
Experimental Study ◽  
Oxygen Transfer ◽  
Air Entrainment ◽  
Nozzle Diameter ◽  
Venturi Tube ◽  
Water Pump ◽  
Significant Difference ◽  
Oxygen Transfer Efficiency ◽  
Aeration Efficiency ◽  
Nozzle Size

A 1.1 kW submersible water pump with a venturi air injector was used in this study to examine the effects of three factors including nozzle diameter (14, 17 and 20 mm), aeration depth (20, 40 and 60 cm), and aeration angle (0, 22.5 and 45°) on standard aeration efficiency (SAE). For maximum air entrainment, HT / DT ratio and DT / DN ratio were equal to zero and 2, respectively. Among the first factor experiments, 14 mm nozzle diameter showed the highest SAE value (P<0.05). Although, 60 cm aeration depth and 45° aeration angle had more SAE value among other depths and angles, but there was not a significant difference (P>0.05) in each aeration depths and angles. Only, the determination coefficient for effect of nozzle diameters on SAE value showed a good result (R2= 0.958). The greatest oxygen transfer efficiency in this study has been achieved with using 14 mm nozzle size, 60 cm depth of aeration, and 45° angle of venturi tube in water aeration that was 1.166 kgO2/ kWh. Venturi aerators are very inexpensive in comparison with other aerators and have some other advantages that can be considered as one of the best devices for water aeration.

The Effect of Nozzle Type on Air Entrainment by Plunging Water Jets

2002 ◽  
Vol 37 (3) ◽  
pp. 599-612 ◽  
Author(s):  
Tamer Bagatur ◽  
Ahmet Baylar ◽  
Nusret Sekerdag
Keyword(s):  
Penetration Depth ◽  
Oxygen Transfer ◽  
Free Water ◽  
Air Entrainment ◽  
Water Jet ◽  
Transfer Efficiency ◽  
Entrainment Rate ◽  
Water Jets ◽  
Air Entrainment Rate ◽  
Oxygen Transfer Efficiency

Abstract In this study, for the plunging water jet aeration system using various inclined nozzle types, bubble penetration depth, air entrainment rate, water jet expansion, effect of water jet circumference at impact point, oxygen transfer coefficient and oxygen transfer efficiency which changed depending on the water jet velocity, were researched in an air-water system. Numerous studies were conducted with circular nozzles. The present study describes new experiments performed with different nozzle types. Three types of nozzles were examined, i.e., those with circular, ellipse and rectangle duct with rounded ends. Experimental results showed that water jets produced with ellipse and rectangle duct with rounded ends nozzles have very different flow characteristics, entrainment patterns on free water jet surface, and submerged water jet region within the receiving tank. Higher air entrainment rate and oxygen transfer efficiency was observed in the rectangle duct with rounded ends nozzle due to water jet expansion. Bubble penetration depth, however, is lower for the rectangle duct with rounded ends nozzle than for the other nozzles. The ellipse nozzle provided the highest bubble penetration depth. These results showed that it is appropriate to use ellipse nozzle in aeration of deep pool and rectangle duct with rounded ends nozzle in the applications where high bubble concentration is desirable.

Oxygen Transfer through Air Entrainment over Stepped Weir

2015 ◽  
Vol 744-746 ◽  
pp. 2297-2300
Author(s):  
Jin Hong Kim
Keyword(s):  
Water Treatment ◽  
Oxygen Transfer ◽  
Hydraulic Jump ◽  
Laboratory Experiments ◽  
Air Entrainment ◽  
Air Pocket ◽  
Oxygen Transfer Efficiency ◽  
Flow Features ◽  
Inception Point ◽  
Free Falling

Oxygen transfer through the air entrainment over the stepped weir by the flow types was presented through the laboratory experiments. In the nappe flow, dominant flow features included an enclosed air pocket, a free-falling nappe impact and subsequent hydraulic jump on the downstream step. Most air was entrained through a free-falling nappe impact and a hydraulic jump. In the skimming flow, air entrainment occurs from the step edges. Downstream of the inception point, the flow is highly aerated at each and every step with very significant splashing. The average values of the oxygen transfer efficiency in the region of the nappe flow and of the skimming flow are about 0.40 and 0.28, respectively. The stepped type of the weir was found to be efficient for water treatment associated with substantial air entrainment.

scholarly journals PERFORMANCE ANALYSIS OF 4-OUTLETS SPRAY AERATOR FOR PROCESSING OF INDIGOFERA LEAVES (Indigofera Tinctoria Linn) BECOMES NATURAL DYE SUBSTANCES

2017 ◽  
Vol 6 (2) ◽  
pp. 76-86
Author(s):  
Ida Bagus Putu Sukadana ◽  
I Made Rajendra ◽  
Ida Ayu Anom Arsani ◽  
I Wayan Suastawa
Keyword(s):  
Oxygen Transfer ◽  
Oxygen Transfer Rate ◽  
Natural Dye ◽  
Operational Characteristic ◽  
Air Velocity ◽  
Bottom Part ◽  
Oxygen Transfer Efficiency ◽  
Aeration Efficiency ◽  
Fermentation Solution ◽  
Sufficient Space

The commonly known natural dye substance processing for traditional clothes, such as batik and tenun (woven cloth) is fermentation. The fermentation process can specifically be continued with extraction to produce indigo paste. The process can be done mechanically, i.e. by stirring process, and chemically. In order to accelerate the production, manual process of aeration can be substituted with jet-spray aerator. The aerator prototype which has been developed is acrylic aerator tube with diameter of 240 mm and thickness of 5 mm. The tube was made 1 m long to provide with a sufficient space for indigo foam. Its bottom part is completed with spiral air hose having five small holes of 0.2, 0.4, and 0.6 mm diameter uniformly located along the height of solution in the tube. The aerator was designed for the 10 litters of fermentation solution of 1 kilogram indigofera leaves. Based on the mass of indigo paste produced, the optimum working condition of the aerator is achieved on 3.8 m/sec air velocity and supply pressure of 2 bar with duration of 60 minutes. The aeration test indicated operational characteristic was quite good, i.e. Oxygen Transfer Rate (OTR) of 3.6 kg/hour, Aeration Efficiency (AE) of 4.8 kg/kWh and factual Oxygen Transfer Efficiency (OTE) of 44%.

An Investigation of Effect of Stepped Chutes with End Sill on Aeration Performance

2003 ◽  
Vol 38 (3) ◽  
pp. 527-539 ◽  
Author(s):  
M. Emin Emiroglu ◽  
Ahmet Baylar
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Transfer ◽  
Aquatic Plant ◽  
Hydraulic Structures ◽  
Oxygen Level ◽  
Oxygen Transfer Efficiency ◽  
Aeration Efficiency ◽  
Stepped Chute ◽  
Aeration Performance ◽  
Small Bubbles

Abstract Dissolved oxygen is essential to healthy streams and lakes. The dissolved oxygen level is an indication of how polluted the water is and how well the water can support aquatic plant and animal life. A higher dissolved oxygen level indicates better water quality. There is a significant oxygen transfer associated with most hydraulic structures because the air entrained into the flow is split into small bubbles, which greatly increases the surface area for transfer. Stepped chutes are a particular instance of this, and the aeration efficiency of such structures has not been studied in the laboratory and field. In this paper, the aeration performance of the stepped chutes with and without end sill was investigated in a large laboratory stepped chute. An empirical correlation predicting the oxygen transfer efficiency was developed for stepped chutes. The results indicated that l/h and s/h had a significant effect on the aeration efficiency of stepped chutes.

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.

A NUMERICAL-EXPERIMENTAL STUDY OF THE AIR ENTRAINMENT FOR SELF ASPIRING BURNERS

2016 ◽  
Vol 15 (2) ◽  
pp. 46
Author(s):  
L. S. Baldani ◽  
P. S. B. Zdanski
Keyword(s):  
Experimental Study ◽  
Finite Volume Method ◽  
Oxygen Concentration ◽  
Flow Rate ◽  
Oxygen Sensor ◽  
Numerical Study ◽  
Air Entrainment ◽  
Nozzle Diameter ◽  
Linear Behavior ◽  
Volume Method

This work presents an experimental and numerical study addressing the effects of air entrainment for self aspiring burners. Within this framework, the work focus on the analysis of four different burners tested with four different nozzles, resulting in a total of sixteen different configurations. The gas used for the tests was methane. Each nozzle diameter provided a different flow rate, which also resulted in a different entrainment, therefore a different oxygen concentration on the ports area, which was measured using an oxygen sensor. The level of oxygen decreased with the increase of the flow rate of the gas, and had a linear behavior with the nozzle diameter. The finite volume method with the realizable k-ε model was then applied to numerically investigate this phenomenon using the commercial software STARCCM+. The results shows that for the sixteen points tested the worst correlation had a relative error of 2.95%, while for the best one was of 0.04%.

The influence of the design of the mixing device on the efficiency of mass transfer during pneumo-mechanical aeration of wastewater

2020 ◽  
Author(s):  
А.Н. Григорьева ◽  
Р.Ш. Абиев
Keyword(s):  
Mass Transfer ◽  
Oxygen Transfer ◽  
Transfer Efficiency ◽  
Oxygen Transfer Efficiency ◽  
Aeration Efficiency ◽  
Mechanical Aeration

Аэрация при очистке сточных вод является самым энергоемким процессом. Затраты на обеспечение биологической очистки кислородом составляют около 60% в структуре себестоимости очистки. Таким образом, эффективность массообмена и снижение расхода воздуха является актуальной задачей для предприятий, которые стремятся повысить экономическую эффективность своей деятельности. Цель данной работы – определить эффективность пневмомеханической системы аэрации с использованием турбинной мешалки и разработанной авторами новой конической мешалки, а также сравнить эффективность диспергирования газа в пневматической и пневмомеханической системах аэрации. В качестве критерия для сравнения выбран показатель SOTE (Standard Oxygen Transfer Efficiency), который является основным технологическим параметром, позволяющим сравнивать эффективность различных аэрационных систем. Второй критерий эффективности – показатель SAE (Standard Aeration Efficiency) – отношение количества растворенного в жидкости кислорода к количеству используемой электроэнергии. В результате проведенных экспериментальных исследований установлено, что коническая мешалка по скорости насыщения воды кислородом работает также эффективно, как и турбинная, потребляя при этом гораздо меньше электроэнергии. С разработкой конического колеса вследствие низкого сопротивления лопастей перемешивание в системе «газ – жидкость» возможно в аппаратах больших размеров, что особенно актуально для аэротенков с небольшой глубиной при биологической очистке сточных вод в условиях, когда эффективность пневматической системы существенно снижается.

Oxygen Transfer Efficiency of the Aeration Process in Refinery Waste Water Treatment

2008 ◽  
Vol 59 (2) ◽  
pp. 220-225
Author(s):  
Miroslav Stanojevic ◽  
Aleksandar Jovovic1 ◽  
Dejan Radic ◽  
Milan Pavlovic
Keyword(s):  
Waste Water ◽  
Experimental Investigation ◽  
Water Column ◽  
Oxygen Transfer ◽  
Mass Concentration ◽  
Waste Water Treatment ◽  
Motor Oil ◽  
Refinery Waste Water ◽  
Oxygen Transfer Efficiency ◽  
Aeration Process

This paper presents the results of an experimental investigation of aeration of water with a corresponding mass concentration of waste motor oil depending on the height of the liquid column for varied flow of air introduced into the water. The aeration process for water column heights of 1 and 2 m were investigated. The purpose of investigations performed on an experimental installation was comparison of technical indicators of the aeration process depending on the height of the water column and air flow in order to achieve more efficient purification of waste water.

Bulking and Foaming Organism Control at Phoenix, AZ WWTP

1992 ◽  
Vol 26 (3-4) ◽  
pp. 461-472 ◽  
Author(s):  
O. E. Albertson ◽  
P. Hendricks
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Retention Time ◽  
Oxygen Transfer ◽  
Average Rate ◽  
Oxygen Transfer Efficiency ◽  
Solids Retention ◽  
Total Nitrogen Removal ◽  
The Cost ◽  
The City

A 1630 L/s activated sludge plant at Phoenix was limited to an average rate of 1050 L/s and operated, at 400-600 mg/L MLSS and 0.8-1.3 day solids retention time (SRT) due to bulking sludge and limited clarification capacity. Higher SRTs also produced uncontrolled Nocardia foaming and low dissolved oxygen due to partial nitrification. The City retained the services of a team of consultants to resolve these problems as well as to upgrade the plant to provide nitrification and total nitrogen removal. An anoxic selector design was implemented within the existing basin and the clarifiers were modified to improve inlet design and sludge transport. The modified advanced wastewater treatment (AWT) plant operating at 1450 L/s has averaged an effluent of 7.6 mg/L BOD5, 8.2 mg/L TSS, 1.3 mg/L NH4N, 4.1 mg/L NO3N and 2.9 mg/L TP. Oxygen transfer efficiency has increased about 80% in the nitrification-denitrification (NdeN) mode. The cost of modification/upgrading to AWT was approximately $730,000 and a 400 L/s increase in hydraulic capacity was realized. Upgrading costs were $5.63/m3 ($0.02/gal.)

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