Coagulation-sedimentation apparatus

A coagulation-sedimentation apparatus comprising:

• a separation tank body;
• a partition member installed in said separation tank body to divide an interior of said separation tank body into an upper chamber and a lower chamber;
• a raw water inlet pipe that introduces water to be treated into said upper chamber;
• and
• a water distributing passage having an upper opening opening into said upper chamber and a lower opening opening into said lower chamber to guide a part of said water from said upper chamber to said lower chamber;
• said upper chamber having in an upper part thereof a first treated water outlet for discharging treated water to an outside;
• said lower chamber having a second treated water outlet above said lower opening of said water distributing passage to discharge the treated water to the outside, said lower chamber further having a floc outlet below said lower opening of said water distributing passage to discharge flocs separated from the water;
• wherein a flow velocity of upward flow of the water toward said first treated water outlet in said upper chamber and a flow velocity of upward flow of the water toward said second treated water outlet in said lower chamber can be controlled to velocities at which flocs in the upward flows can settle.