First, use flotation technology in recent years is widely used in water supply and drainage and waste water treatment, it can be difficult to effectively remove the wastewater floc precipitation frivolous. Second, the characteristics 1, large capacity, high efficiency, small footprint. 2, processes and equipment structure is simple, easy to use and maintain. 3, to eliminate bulking. 4, when the aerated water flotation for the removal of surfactant and smell have a significant effect, while increasing the dissolved oxygen in the water due to the aeration for subsequent processing to provide favorable conditions. 5, low temperature, low turbidity, algae contain more water, using flotation method can achieve the best results. Third, it works: wastewater pollutants into non-dissolved organic matter and dissolved substances (ie SS), dissolved organic matter, under certain conditions, can be transformed into a non-solution solution substance, one method of sewage disposal is to join coagulants and flocculants make the most of dissolved organic matter conveyed into non-soluble substance, then all or most of the non-solution solution substances (ie SS) removed to achieve the purpose of purifying contaminated water, and the main method is to remove SS use flotation methods. After dosing reaction effluent into the flotation of the mixing zone, and after the release of dissolved gas and water mixed in contact, so that floc adheres to the fine bubbles, and then into the flotation zone. Air buoyancy effect floc formation of dross in the fall to the water, the lower water flow through the sump to clean water tank, the part of the dissolved gas reflux for use, the remaining water flows out through the overflow opening. DAF water surface scum buildup to a certain thickness after the scraping foam machine after scraping into flotation machine sludge tank discharge.