In the raw water, add coagulant, and in the mixing pond, ensure a certain velocity gradient through the agitation of the mixer to rapidly mix the coagulant with the raw water. The sedimentation pond is divided into clarification and sedimentation sections. The clarification agent is added to the clarification pond. The tank's turbine mixer enables multi-circulation rate agitation, shearing the suspended solids in the water, and reforming them into large flocs that are easy to settle. The sedimentation pond in the equipment is divided into a preliminary sedimentation area and a inclined tube sedimentation area by baffles. In the preliminary sedimentation area, easily settled flocs quickly settle, while the fine flocs that are not easily settled before sedimentation are captured by the inclined tubes. The effluent is collected and discharged through the sump at the tank top.