english 1. Dissolved air and released air
In the dissolved air tank, by introducing air into the water and applying a certain pressure, a large amount of air is dissolved in the water to form dissolved air water. At this time, the air in the water is in a supersaturated state. When the dissolved air water is transported to the flotation tank and suddenly depressurized, the supersaturated air quickly precipitates in the form of tiny bubbles. These bubbles are usually about tens of microns in diameter and have a large specific surface area and surface energy.
2. Particle and bubble attachment
The surface properties of suspended particles in wastewater vary. Some particles have hydrophobic surfaces and are easily attached to bubbles. When bubbles collide with particles, due to the low gas-liquid interface energy on the bubble surface, the particles will overcome the resistance of the surrounding water and attach to the bubble surface. For some highly hydrophilic particles, flocculants or coagulants can be added to the wastewater to change the surface properties of the particles and make them easy to attach to bubbles.
3. Flotation separation
The bubbles attached with suspended particles have a lower density than water, so they quickly float to the water surface under the action of buoyancy to form a scum layer. The clean water from which the suspended particles are separated flows downward under the action of gravity and is discharged from the bottom of the flotation tank, thus achieving solid-liquid separation. The scum layer can be regularly scraped off by scraping equipment to achieve the purpose of removing suspended pollutants in the wastewater.
