Pressurized Dissolved Air Floatation is the process of air-float water treatment with pressurized dissolved air. It is characterized in that the treated sewage (all and part) is pressurized to 3-4 kg / cm2 with a water pump and sent into a special air tank for dissolving the air in the tank sufficiently and then released in the flotation tank Suddenly reduced to atmospheric pressure, then dissolved in the water supersaturated air as a form of micro-bubbles from the pool to escape, the water suspended particles or oil particles to the surface of the formation of scum to exclude the water. Engineering often used part of the sewage pressurized dissolved gas method, this method of power, equipment, small volume, less coagulant consumption, easy to operate, not blocked. This method of processing efficiency of up to 90%, but the highest power consumption.