Design of a Deflector for Water Aeration in Wastewater Treatment

2012 ◽  
Author(s):  
R. S. Amano ◽  
Ammar Alkhalidi ◽  
Patrick Bryar
Keyword(s):  
Waste Water ◽  
Wastewater Treatment ◽  
Power Consumption ◽  
Energy Cost ◽  
Oxygen Transfer ◽  
Energy Crisis ◽  
Water Tank ◽  
Oxygen Transfer Efficiency ◽  
Oxygenated Water ◽  
Air Blower

The aeration phase within wastewater treatment is the most power consuming step required in the treatment of waste water. After the energy crisis in 1970s increasing attention has been paid for this step to reduce the energy cost [1]. Higher standard oxygen transfer efficiency (SOTE) reduces the amount of air required to aerate wastewater which reduce the air blower power consumption. In this study SOTE was investigated for the case of adding a bubble deflector, i.e. an external geometry that directs the bubbles toward the less oxygenated water, which improves the efficiency and eliminates the effect of dead zones in a rectangular water tank.

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.)

Power Generation and Oxygen Transfer Analyses for Micro Hydro-Turbine Installed in Wastewater Treatment Aeration Tank

2021 ◽  
pp. 1-16
Author(s):  
Abdel Rahman Salem ◽  
Alaa Hasan ◽  
Ahmad Abdelhadi ◽  
Saif Al Hamad ◽  
Mohammad Qandil ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Oxygen Transfer ◽  
Power Loss ◽  
Wastewater Treatment Plants ◽  
Aeration Tank ◽  
Hydro Turbine ◽  
Oxygen Transfer Efficiency ◽  
Aeration Process ◽  
The U.S ◽  
Water Height

Abstract This study targets one of the major energy consumers in the U.S. It suggests a new mechanical system that can recover a portion of the energy in Wastewater Treatment Plants (WWTPs). The proposed system entails a hydro-turbine installed above the air diffuser in the aeration tank to extract the water-bubble current's kinetic energy and converts it to electricity. Observing the optimum location of the turbine required multiple experiments where turbine height varies between 35% and 95% (water height percentages above the diffuser), while varying the airflow between 1.42 L/s (3 CFM) and 2.12 L/s (4.5 CFM) with a 0.24 L/s (0.5 CFM) increment. Additionally, three water heights of 38.1 cm (15”), 53.4 cm (21”), and 68.6 cm (27”) were considered to study the influence of the water height. It was noticed that the presence of the system has an adverse effect on the Standard Oxygen Transfer Efficiency (SOTE). Therefore, a small dual-blade propeller was installed right above the diffuser to directly mix the water in the bottom of the tank with the incoming air to enhance the SOTE. The results showed that the maximum reclaimed power was obtained where the hydro-turbine is installed at 65% - 80% above the diffuser. A reduction of up to 7.32% in SOTE was observed when the setup was placed inside the tank compared to the tank alone. The addition of the dual-blade propeller showed an increase in SOTE of 7.27% with a power loss of 6.21%, ensuring the aeration process was at its standards.

Study of Air Bubble Formation for Wastewater Treatment

2011 ◽  
Author(s):  
Bryan A. Miletta ◽  
R. S. Amano ◽  
Ammar A. T. Alkhalidi ◽  
Jin Li
Keyword(s):  
Wastewater Treatment ◽  
Oxygen Transfer ◽  
Surface Membrane ◽  
Bubble Formation ◽  
High Oxygen ◽  
Transfer Efficiency ◽  
Intimate Contact ◽  
Rubber Membrane ◽  
Unit Process ◽  
Oxygen Transfer Efficiency

Aeration, a unit process in which air and water are brought into intimate contact, is an extremely important step in the process of wastewater treatment. The two most common systems of aeration are subsurface and mechanical. A mechanical system agitates the wastewater by various means (e.g. paddles, blades, or propellers) to introduce air from the atmosphere. Subsurface aeration is the release of air, in the form of bubbles, within the tank of wastewater to supply the microorganisms with the required amount of oxygen they need to metabolize and break down the organic material suspended in the wastewater. The bubbles of Air are released from the bottom of the wastewater tank through diffusers. These diffusers have a surface membrane, usually made of punched rubber, to create the fine bubbles with high oxygen transfer efficiency from supplied air to the diffusers. Since the energy crisis in the early 1970’s, there has been increased interest in these systems due to its high oxygen transfer efficiency. This paper covers experimentation of different air diffuser membranes, varying in material, used in the aeration process of wastewater treatment. Rubber, EPDM rubber (ethylene-propylene-diene Monomer) and PTFE Polytetrafluoroethylene membranes coated membranes were tested. Experimental results showed that the rubber membrane produced the smallest bubble size against expectation. This could be a result of the coating being on the top surface only and the bubble starts from inside the punch.

Monitoring the oxygen transfer efficiency of full-scale aeration systems: investigation method and experimental results

2014 ◽  
Vol 70 (1) ◽  
pp. 8-14 ◽  
Author(s):  
Riccardo Gori ◽  
Alice Balducci ◽  
Cecilia Caretti ◽  
Claudio Lubello
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Oxygen Transfer ◽  
Treatment Plant ◽  
Transfer Efficiency ◽  
Chemical Cleaning ◽  
Total Recovery ◽  
Aeration System ◽  
Oxygen Transfer Efficiency ◽  
Urban Wastewater Treatment

This paper reports the results of a series of off-gas tests aimed at monitoring the evolution of the oxygen transfer efficiency in an urban wastewater treatment plant (3,500 population equivalent) located in Tuscany (Italy). The tests were conducted over a 2-year period starting with the testing of the aeration system. It was found that in the absence of membrane-panel cleaning operations, the oxygen transfer efficiency under standard conditions in process water (αSOTE) dropped from 18 to 9.5% in 2 years. This gives rise to a 40% increase in the wastewater treatment plant annual energy costs. The on-site chemical cleaning of the diffusers allowed for an almost total recovery of the transfer efficiency (αSOTE equal to 16%). The use of the off-gas method for monitoring the oxygen transfer efficiency over time is therefore essential for enabling correct planning of the cleaning operations of the diffusers and for cutting the energy consumption and operating costs of the aeration system.

scholarly journals Transient Process Modelling in Waste Water Aeration Unit

2006 ◽  
Vol 1 ◽  
pp. 269
Author(s):  
A. Šnīders
Keyword(s):  
Waste Water ◽  
Control System ◽  
Water Temperature ◽  
Oxygen Concentration ◽  
Transient Process ◽  
Oxygen Transfer ◽  
Control Object ◽  
Transfer Efficiency ◽  
Aeration Tank ◽  
Oxygen Transfer Efficiency

To minimize the expenditure of electrical energy for communal waste water biological treatment the simulation and investigation of oxygen transfer efficiency in aeration tank have been made. Soluted oxygen transfer efficiency ? 0 (Fig.1.) is one of the main important factor directly estimating the expenditure of electrical power for waste water aeration. The research object is an aeration tank (Fig.2.) with one input impact -–the air blower’s capacity Lg (m3/h), one output controlled parameter – dissoved oxygen concentration C (g/m3) and several perturbances such as waste water temperature T (oC), waste water afflux Q (m3/h) and biological oxygen need La (g/m3) for complete purification. Oxygen’s transfer efficiency depends on the waste water temperature, the depth of aerator immersion h (m), air flow intensity ? d (m3/disc.h) and the air diffusor’s density ? s. For simulation and practical design of the air blower control system the equations of statics C=f(Lg, Q, La, T, h, ? d , ? s) and dynamics C=f(t) have been compiled. That made possible to estimate the static gains for control channel Ka and for perturbances Kq, KT as well as the time constant of the aeration tank Ta. The analysis prove that the aeration tank is a non-stationary control object with the variable static and dynamic parameters and needs adaptive controller with predication of oxygen consumption. The block diagram for transient process simulation of the oxygen concentration control system have been compiled using model of the actual PID controller and the “Matlab” subprogram “Simulink”.

A New Dimensionless Criterion for the Oxygen Transfer Efficiency in Both Surface and Subsurface Aeration Systems

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2531-2534 ◽  
Author(s):  
T. Ognean
Keyword(s):  
Power Consumption ◽  
Oxygen Transfer ◽  
Rotational Velocity ◽  
Full Scale ◽  
Transfer Efficiency ◽  
Dimensionless Number ◽  
Efficiency Criterion ◽  
Higher Power ◽  
Oxygen Transfer Efficiency ◽  
The One

The effect of power consumption on oxygen transfer efficiency has been evaluated in both surface and subsurface aeration systems. For this purpose a new dimensionless number To, named “efficiency criterion”, has been proposed.Using this number, the efficiency of different aeration systems could be compared.The comparison has been achieved by taking into consideration the data furnished by full-scale experimental models.The results have proved that of two aerators with identical diameters and the same rotational velocity reaching the maximum To, the one with a higher power consumption had a higher efficiency.The results regarding the subsurface aeration systems show that the efficiency of aeration equipment can be continuously increased if the bubbles' diameters are decreased.

DESIGN PLANNING WASTEWATER TREATMENT PLANT OF NATA DE COCO INDUSTRY WITH THE ACTIVATED SLUDGE PROCESS

2016 ◽  
Vol 9 (2) ◽  
Author(s):  
Dinda Rita K. Hartaja ◽  
Imam Setiadi
Keyword(s):  
Waste Water ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Appropriate Technology ◽  
Waste Water Treatment Plant ◽  
Activated Sludge Process ◽  
High Level

Generally, wastewater of nata de coco industry contains suspended solids and COD were high, ranging from 90,000 mg / l. The high level of of the wastewater pollutants, resulting in nata de coco industry can not be directly disposed of its wastewater into the environment agency. Appropriate technology required in order to process the waste water so that the treated water can meet the environmental quality standards that are allowed. Designing the waste water treatment plant that is suitable and efficient for treating industrial wastewater nata de coco is the activated sludge process. Wastewater treatment using activated sludge process of conventional (standard) generally consists of initial sedimentation, aeration and final sedimentation.Keywords : Activated Sludge, Design, IPAL

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