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Kunshan Pinhong EPT Co.,Ltd
Kunshan Pinhong EPT Co.,Ltd
Add : (Qiandeng Yuanchuang Base) No. 125, Jinxing South Road, Qiandeng Town, Kunshan, Jiangsu, China
Tel : （0086）15995617314
Fax : +86-512-50130524
E-mail :lvfang@ksphxs.com
1. Application of aerator in sewage treatment
According to the aerobic conditions of the participating microorganisms, biological treatment methods can be divided into two types: aerobic and anaerobic. Generally speaking, the aerobic method is more suitable for lower-concentration sewage, such as ethylene plant sewage; the anaerobic method is more suitable for the treatment of higher-concentration sludge and sewage. Aerobic biological treatment can be divided into activated sludge method and biofilm method.
Activated sludge method is an artificial enhancement method of water self-purification, which relies on activated sludge as the main body to remove organic matter in sewage. The aerobic microorganisms present in activated sludge can only function in the presence of oxygen.
In the aeration tank of the sewage treatment biochemical system, the oxygenation efficiency is positively correlated with the growth of aerobic microorganisms. The amount of dissolved oxygen should be considered comprehensively based on the number, physiological characteristics, substrate properties and concentration of aerobic microorganisms.
Only in this way can the activated sludge be in a state of degrading organic matter. According to the test, the dissolved oxygen in the aeration tank should be kept at 3 ~ 4 mg/L. If the oxygen supply is insufficient, the performance of the activated sludge will be poor, resulting in a decrease in the wastewater treatment effect. In order to ensure a sufficient supply of oxygen, it must rely on a device such as an aerator.
2. Aeration principle
Aeration is a means to make air and water come into strong contact. Its purpose is to dissolve oxygen in the air in the water, or to remove unwanted gases and volatile substances from the water into the air. In other words, it is a means to promote the exchange of gas-liquid substances. It also has other important functions such as mixing and stirring.
According to the double membrane theory, there are gas and liquid films on the "gas-water" interface, and air and liquid flow outside the gas and liquid films, which is a turbulent state; there is laminar flow between the gas and liquid films without convection. Under certain conditions, pressure gradients and concentration gradients will appear. If the oxygen concentration in the liquid film is lower than the saturation concentration of oxygen in the water, the oxygen in the air will continue to diffuse inward through the liquid film and enter the water body, so the liquid film and gas film will become an obstacle to oxygen transmission.
This is the double membrane theory. Obviously, the most effective way to overcome the liquid membrane barrier is to quickly change the "gas-liquid" interface.
Aeration stirring is just like this. The specific method is to reduce the size of the bubbles, increase the number of bubbles, increase the turbulence of the liquid, increase the installation depth of the aerator, and prolong the contact time between the bubbles and the liquid. Based on this practice, aeration equipment is widely used in sewage treatment.
3. Aeration type and aeration function
Aeration types are generally divided into two categories: one is blast aeration, and the other is mechanical aeration.
Blast aeration is an aeration method that uses the diffuser's diffuser or diffuser to introduce bubbles into the water. Generally speaking, this method is used for sewage treatment in ethylene plants. Mechanical aeration refers to the aeration method that introduces air bubbles through impellers and other instruments. All aeration equipment should meet the following three functions:
(1) Generate and maintain effective gas-water contact, and maintain a certain dissolved oxygen concentration in the water when biological oxidation continues to consume oxygen;
(2) The aeration zone produces sufficient mixing and circulating water flow;
(3) Maintain a sufficient liquid velocity to make the biological solids in the water suspended.