Steel mill wastewater can be divided into indirect cooling water facilities, equipment and products directly to the production process cooling water and wastewater. According to different steelmaking processes, such as steel by a combustion method and unburned method, its production process effluents have very different, additionally, one of the characteristics of steel production is interrupted production, so the composition and properties of wastewater all changes with the refining cycle varies. The main wastewater treatment wastewater steelworks is BOF gas cleaning wastewater, often referred to as converter dust waste. The converter steel mill dust wastewater treatment should focus on solving the suspension of the rule of reason, the equilibrium temperature stability and water quality problems. Coagulation and sedimentation of suspended solids treatment process is as follows: Before the dust wastewater into the sedimentation tank, first by using the principles of gravity coarse particle separation device (hydrocyclone or spiral classifier, etc.), to remove large particles of suspended impurities, and then into the settling tank. In the sedimentation tank ditch Ming dosing PH adjusting agent and polymer flocculant dosing, so settling pond in achieving a common flocculation of suspended solids and precipitation fouling, then, in the sedimentation tank effluent dosing inhibitor . Thus, not only solve the problem of waste water clarification, but also solve the problem of water-stable, so as to achieve a better treatment effect. Sewage dosing PAC PAC, polymer suspensions flocculated water into small floc; when water is added polyacrylamide PAM, through cooperation with a variety of key, making it more strongly bound floc, and precipitated it. By production practices that: dosing PAC, PAM composite chemicals best