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Analysis of foam problems in aeration tanks and their causes

Source:     Time:13 October 2020

aeration diffuser precautions

The foam problem of the aeration tank can reflect the operation of the biochemical system. A better classification method for the biochemical system foam is to classify by color and viscosity, because confirming the different color and viscosity of the foam can guide us to judge the current activated sludge status.

1. Brown-yellow foam
The amount of foam is small when it is produced, and a small amount of liquid is produced near the aeration group, gradually dissipates along the radiation direction, and starts to accumulate when it reaches the surrounding corners. The color of the foam is brown and the color of the foam is the same as that of the activated sludge at that time. From the formation of the foam to the accumulation process, the foam is in a fragile state, so this type of foam will not accumulate in a short time and cause a large amount of scum.
Cause Analysis:
Activated sludge is in an aging state, part of the activated sludge is disintegrated due to aging, suspended in the activated sludge mixture, and uniformly attached to the foam in the aerated state, resulting in prolonged foam bursting time, which creates conditions for foam accumulation .

2. Gray-black foam
The foam quantity, production process, accumulation, and fragility are the same as the brown-yellow foam, but its color contains black components, and the accumulated product is also gray-black. Observe the color of the activated sludge of the entire biochemical system is also slightly gray Feeling black.
Cause Analysis:
The activated sludge is in an anoxic state. The hypoxic state can cause the activated sludge to have a local anaerobic reaction. In this way, the activated sludge that was originally in aerobic state will die in the process of this transformation, and it will also Adhering to the air bubbles during aeration.
Therefore, if you see that the foam produced is gray-black, in addition to confirming whether the influent water contains black dye wastewater, the main thing is to confirm whether there is an anaerobic situation caused by insufficient aeration in the biochemical tank.

3. White foam
There are many reasons for white foam, but the main common causes are excessive load, excessive aeration, and detergent influx. When distinguishing what causes the white foam, the viscosity of the foam can give us a lot of reference.
Under normal circumstances, the viscous and unbreakable foam is common in the activated sludge load is too high, and the foam at this time has a bright white color and good accumulation, while the viscous and breakable foam is common in the over aeration of the activated sludge And the color of the foam at this time is old white, poor accumulation, only partial accumulation will occur, white foam will also occur in the inflow of detergent, because the existence of detergent increases the surface tension of the water body, and finally leads to the formation of foam .

4. Colored foam
Colored foam often occurs when the colored wastewater flows into the biochemical system. Usually, these colored wastewater has a higher concentration of organic matter. Under the action of aeration, it is easy to cause bubbles similar to those produced under high load. Since the water itself has a color, the naturally generated foam will also have a color.
Another situation is that sewage or wastewater is rich in surfactants or detergents. After flowing into the biochemical system, it will naturally cause foam to be produced. Under sunlight, the surface of these foams will produce colorful colors. This is useful for judging such foams. The reason for the occurrence of is very helpful.

Jiangsu Envset adopts industry-leading MBBR technology in the aeration wastewater treatment tank. The MBBR biological media we produce are widely used in many fields. If you have any questions about the foam problem in the aeration tank, please contact us.

Tag: foam problems in aeration tanks, aeration wastewater treatment tank, aeration diffuser precautions