The environmental assessment of industrial effluents (containing organic pollutants and minerals without proper treatment), generated by the mineral fertilizer factory and emptied into the seacoast, revealed the concentrations intense of suspended solids (SS).The wastewater treatment is a multi-step process to remove contaminants. At first, large solid particles were removed by sedimentation, flotation and filtration. In a second step, the biological treatment is aggregated by forming the smaller particles, which is called flocs. These flocs can be easily removed by sedimentation. The present investigation studying the separation of water flocs in a circular secondary clarifier. A mixture model is used to model the multiphase turbulent flow in the tank.