Printing and dyeing wastewater treatment equipment mainly for bleaching and dyeing wastewater high chroma difficult, difficult to reduce the design and development of high COD can be effectively treated so that dyeing wastewater discharge standards. First, the device utilizing the principle of anaerobic and aerobic bacteria consume their life activities of organic pollutants in sewage, while biological floc formed by microbes like the suspension and colloidal organic pollutants instability flocculation, adsorption on activated sludge surface, degradation of organic matter, and ultimately achieve the effect of sewage purification. Within the device is equipped with underwater aeration, pushing through the water to form a dual-function aeration. When sewage treatment, sewage flows from the top of the unit aeration zone, underwater aerator aeration and agitated plug-flow of sewage into the water quickly mixed with the original mixture to maximize adapt to changes in water quality. Aerators push through the water and underwater aeration dual function, sewage aeration zone regularly circulates improve sewage dissolved oxygen content. Since the sewage continues to circulate in the aeration zone, water zone points more evenly, the number of microorganisms, nature is basically the same, so the work of the various parts of the aeration zone almost unanimously. This entire biochemical reactions under good control in the same condition. Organic matter is gradually degraded by microorganisms, sewage purification. Up water purification efficiency indicators meet the state 'textile dyeing and finishing industry emission standards "(GB 4267-92) emission standards. Also according to customer requirements further support, as the depth of the ozone strong oxidizing process, to achieve "urban recycling landscape and environmental water quality standards" (GB / T 18921-2002) standard, recycled. Second, the process characteristics 1, biological contact oxidation process, than the activated sludge tank and small size, strong adaptability to water quality, good resistance to shock loading performance, water quality and stability, no sludge expansion; 2, packing large surface area , easy to hang microbial film, stripping, organic load under the same conditions, the organic removal efficiency, stable and reliable, while eliminating the need pharmaceutical dosing, subsequent cost savings, reduce operating costs; 3, hydrolysis acidification can effectively reduce sewage color, improve the biodegradability of wastewater, reducing post-processing load, and for the latter adding greatly reduce the amount of bleaching agent, saving investment; 4. ideal precipitation effect, achieve better water quality; 5, bleaching treatment, decolorization rate reached 99.4% above, to color emission standards; 6, proper handling sludge, to ensure the system stable and reliable operation, easy mud, reduce manual operation; 7, a unique construction method to minimize odor diffusion; 8, operation and management simple, can be adjusted according to the actual running conditions, in order to obtain the best operating results; 9, high purification efficiency, BOD removal rate of 85% to 90%, more than 99% color removal, water all meet the national second level or an emission standard, 10, can handle printing and dyeing industry, sewage and similar industrial organic wastewater. Third, the scope of application of the device is widely used in knitting and dyeing wastewater, other types of hair dyeing wastewater, sewage silk dyeing, chemical fiber dyeing wastewater, woven cotton and cotton blended fabric dyeing sewage and other high, medium and low concentrations printing printing and dyeing wastewater treatment effluent.