How to choose an aeration device for the oxidation ditch of 4 5m in water depth

Oxygen requirement.

The aerobic zone oxygen demand should be considered carbonized oxygen demand. Endogenous respiration oxygen demand, nitrification oxygen demand, and denitrification process should consider the oxygen demand generated by the nitrification process. The actual oxygen demand of the above process should be converted to the standard oxygen demand, and the equipment should be selected according to the situation.

Aeration equipment should be designed with oxygen transfer efficiency under standard conditions (20 and 0 mg l dissolved oxygen, with tap water). When the temperature and altitude are different, the corresponding correction should be made. For multi-ditch oxidation ditches or oxidation ditches with integrated aeration and sedimentation, the aerobic demand coefficient of the aeration equipment should be included when the aeration equipment is not working.

The concentration of dissolved oxygen in the pool should be less than when only the carbon source contaminants are removed. Considering that the concentration of dissolved oxygen in the pool is not less than mg L during nitrification, the concentration of dissolved oxygen in the anoxic pool is less than mg L, and the concentration of dissolved oxygen is close to 0 mg L.

Aeration equipment. 1) Aeration special aeration equipment for oxidation ditch, aeration brush can be selected. Aeration turntables, surface aerators, jet aerators, catheter aerators, etc. The aeration in the oxidation ditch should meet the following requirements:

provide the amount of oxygen needed for biological treatment; Make oxygen, organic matter, and microorganisms fully mixed and contacted; The mixture is always in suspension to prevent sludge sedimentation; Promote the continuous circulation of water; The facility's oxygenation capacity is easily adjustable and has the flexibility to adapt to changes in needs. The selection of aeration equipment should be comprehensively considered in combination with process requirements (such as pool type, water depth, denitrification, etc.). The power efficiency of the oxygenation device and the utilization rate of oxygen should be appropriately high to ensure the supply capacity.

2) Mixing According to the lifting capacity of the aeration equipment and the cross-sectional area of the aeration tank, the design of the aeration equipment should maintain a minimum average velocity. Stirrers in oxidation ditches, anoxic and anaerobic ponds. A submerged mixer is available for easy maintenance and meets the following requirements:

Prevents activated sludge sedimentation; It is the reflux sludge that is fully mixed with the raw sewage; Maintain an environment for the treatment of anaerobic organisms.

6) The position of the aerator The aerator should be located exactly at the oxidation ditch in the straight section downstream of the curve. The vertical surface exposer should be located at the curve. The submersion depth of the rotating brush (rear turntable) should be 100 300mm, and the rotating brush ** disc) should be spread in the entire groove width direction, and there should be enough place to install the bearing.

8) Design calculation of aeration equipment.

Oxygen demand calculation.

a.Carbon source oxygen demand (d1).

b.Nitrification oxygen demand (d2).

c.The amount of oxygen produced by denitrification (d3).

d.Total oxygen demand (d).

d=d1+d2—d3=13830kg/d=576kg/h

Standard Oxygen Demand Calculation SOR is calculated according to the following formula (whichever is taken);

Configure the aeration equipment The lifting power that needs to be configured ( ).

Therefore, at least 14 aeration brushes with a motor power of 32kw, a diameter of 1000mm and a shaft length need to be selected. Considering the statistical utilization rate of the three-ditch oxidation ditch, a total of 48 rotating brushes were required for the three ditches.

There are two common options, a vertical surface aerator or a blast aerator with a flow booster.

Each has its own strengths, and the specific calculation refers to the outdoor drainage design code. As for the choice, the advantages of the vertical meter exposer are simple operation and management, minimal maintenance workload, and slightly higher power consumption. The flow pusher plus blast aeration saves electricity, and the disadvantage is that it is a little troublesome during maintenance.

Your design is incomplete, and only when you say it is specific can others give advice!

Once upon a time, the first generation of oxidation ditches was aerated by the aeration head. However, the oxidation ditch needs the power to push the flow, and mechanical aeration, whether it is a surface brush or an umbrella aerator, can provide additional impetus while providing oxygen, which can help the oxidation ditch flow. So it gradually evolved into the use of these mechanical aeration methods.

Moreover, mechanical aeration has an advantage over the aeration head aeration method, that is, the dissolved oxygen stratification in the water is obvious, and the most direct structure of this benefit is to form an anaerobic anoxic aerobic stratification in the oxidation ditch, which has a great benefit to denitrification and improve its impact resistance. You must know that the design of the oxidation ditch was not made according to the idea of AO in the early days, or it was an ordinary oxidation ditch, and the modern Carrousel type formed a ditch type similar to the AO process.

After the birth of oxidation ditches, the most popular is of course mechanical aeration. However, the latest research has begun to emerge on the design and implementation of blast aeration + flow pusher.

The advantage of mechanical aeration in the past is that it can form a well-structured aerobic and anoxic environment, and the maintenance management is very simple, forming a good flow effect. The disadvantage is that the energy consumption is on the high side.

The latest is the blast aeration plus high-efficiency flow pusher. It combines the low energy consumption advantages of blast aeration with the high flow rate of traditional mechanical aeration oxidation ditches. However, the requirements for the flow pusher are relatively high, and the current flow pusher seems to be particularly good, which can maintain the service life for many years.

Mechanical aeration, no need to push the flow!

Because, mechanical explosion, this is more efficient, and it helps to have a chemical reaction with it.

The commonly used aeration equipment in the process of oxidizer Huipaigou includes aeration brush, aeration turntable, surface aerator, jet aerator and catheter aerator. When choosing aeration equipment, while satisfying the required oxygenation efficiency, it is necessary to choose a stable and reliable aeration device with small electric power as much as possible. Specifically, the following requirements need to be met:

Able to provide sufficient dissolved oxygen; Mix oxygen, organic matter and microorganisms thoroughly; Ensure that the mixture is always in suspension to prevent sludge sedimentation; Promote the continuous circulation of water; The oxygenation capacity of the facility should be easily adjustable. Flexibility to adapt to aerobic changes. However, the design should also be determined in combination with the specific requirements of the process and various factors.