Dissolved air flotation machine is an efficient sewage treatment equipment with large processing capacity and high efficiency, widely used in sewage treatment processes. Below, based on our company's equipment, we will briefly introduce the working principle of the dissolved air flotation machine. The working principle of the dissolved air flotation machine is as follows: sewage is first treated and reacted, and then enters the mixing zone of the air flotation. It mixes and contacts with the released dissolved air water, causing the floc to adhere to fine bubbles, and then enters the air flotation zone. Under the action of air buoyancy, the floc floats to the water surface to form scum. The clean water in the lower layer flows to the clean water tank through a water collector, and a portion of it returns to be used as dissolved air water. The remaining clean water flows out through the overflow port. After the scum on the water surface of the air flotation tank accumulates to a certain thickness, it is scraped into the air flotation machine sludge tank by a foam scraper and discharged.

There are two types of air intake methods for the dissolved air flotation machine: forward pump air intake and backward pump air intake.

The dissolved air flotation machine pumps forward air, which is returned to the suction pipe through a branch pipe led out by the water pump pressure pipe. A hydraulic injector is installed on the branch pipe. When the wastewater passes through the hydraulic injector, it creates a negative pressure. The air is sucked in and mixed with the wastewater, and then sent to the dissolved air tank through the suction pipe and water pump. This method eliminates the need for an air compressor and is relatively simple, with even water and air mixing. However, the water pump must use a self priming water inlet and maintain a water head of over 1m. In addition, its maximum suction capacity cannot be greater than 10% of the water pump's suction capacity, otherwise, the water pump will not work stably and cavitation will occur.

After the pump, compressed air is usually introduced through the pressure pipe. This method ensures stable operation of the water pump and does not require it to work under positive pressure, but requires air supply from the air compressor. To ensure good gas dissolution effect, the volume of the gas dissolution tank is also relatively large, and generally requires the use of more complex filled gas dissolution tanks.