1、 Purpose:
In recent years, air flotation technology has been widely used in water supply and drainage as well as wastewater treatment. It can effectively remove light flocs that are difficult to precipitate in wastewater.
2、 Characteristics:
1. Large processing capacity, high efficiency, and small footprint.
2. The process and equipment structure are simple, easy to use and maintain.
3. Can eliminate sludge swelling.
4. Aeration into the water during air flotation has a significant effect on removing surfactants and odors from the water. At the same time, aeration increases dissolved oxygen in the water, providing favorable conditions for subsequent treatment.
5. For water sources with low temperature, low turbidity, and high algae content, air flotation can achieve good results.
3、 Working principle:
The pollutants in sewage are divided into dissolved organic matter and insoluble substances (i.e. SS). Dissolved organic matter can be converted into non soluble substances under certain conditions. One of the methods of sewage treatment is to add coagulants and flocculants to convert most of the dissolved organic matter into non soluble substances, and then remove all or most of the non soluble substances (i.e. SS) to achieve the purpose of purifying sewage. The main method of removing SS is to use air flotation.
After the chemical addition reaction, the sewage enters the mixing zone of air flotation and comes into contact with the released dissolved air water, causing the flocs to adhere to fine bubbles before entering the air flotation zone. Under the action of buoyancy, flocs float towards the water surface to form floating scum. The clear water in the lower layer flows through the collector to the clear water tank, and a part of it is refluxed for use as dissolved air. The remaining clear water flows out through the overflow port. After the floating slag on the surface of the air flotation tank accumulates to a certain thickness, it is scraped into the sludge tank of the air flotation machine by a scraper and discharged.

1. For the treated portion of clean water (with a design index of 20-30%, usually 30%), it is pressurized by an air floating circulation pump and mixed with air in a dissolved water tank. The air dissolves into the water, and the dissolved air efficiency reaches over 80%;
2. The air in the dissolved gas tank is automatically replenished to the dissolved gas tank by the air compressor controlled by the liquid level automatic controller;
3. The dissolved water coming out of the dissolved gas tank has a pressure of 0.3~0.4MPa. After passing through a release device, the pressure of the dissolved water is reduced and released, reducing the pressure of the dissolved water to zero or negative pressure. The air dissolved in the water is released from the water, forming microbubbles with a particle size of 20-50um. The microbubbles combine with suspended solids in the sewage, and some microbubbles directly grow in the suspended solids, reducing the specific gravity of the suspended solids in the sewage until they float to the surface of the water body;
4. Form a large amount of floating slag, and then install a chain scraper on the air flotation tank to remove the floating slag;
5. The clean water at the bottom of the air flotation tank, after passing through the clean water collection pipe and entering the air flotation tank, can be directly discharged outward or enter the subsequent treatment equipment, except for some as reflux dissolved air water.