Dissolved air floatation pump uses air floatation method, that means the micro-bubbles formed by releasing the compressed air instantaneously or mechanical shear conduct the flotation. The specific working principle is as follows:
When it comes to dissolved air floatation pump, it is an operation process that selectively adsorbs hydrophobic contaminant ions from a heterogeneous system which contains wastewater, pollutants and bubbles, and separates and removes them from the water in the form of foam. Air flotation is a water treatment technology: a large number of micro bubbles are injected into the water or produced by electrolysis, and they will stick to the particles of solid or liquid pollutants in the wastewater with a density which is close to that of water, then an air floating body with a density less than that of water will be formed. Under the effect of buoyancy, the air floating body floats to the water surface to form scums, which will take part in solid-liquid or liquid-liquid separation. Air floatation method is mainly used to remove suspended solids, oil and fat of relative density from waste water. It can also be used to concentrate high concentration waste water and then dry it by belt filter press.
It is the precondition of air flotation separation that the contaminant particles in the waste water can be adsorbed on the bubbles stably and float up with the bubbles. Therefore, the contaminant particles removed should have a hydrophobic surface. In order to improve the separation effect of air flotation, it often takes measures to change the surface characteristics of solid or liquid contaminant particles, such as adding a certain amount of suspending agent to make the hydrophilic particles into hydrophobic particles, and adding demulsifier (coagulant) to emulsified oil wastewater to accumulate the emulsified oil which is difficult for air floatation into suspended solids and remove them.