FLOCCULATION AND SEDIMENTATION APPARATUS

PROBLEM TO BE SOLVED: To provide a flocculation and sedimentation apparatus which can discharge sludge without delay when starting operation without depending on a property of water to be treated and by using no washing water.SOLUTION: A slurry blanket type flocculation and sedimentation apparatus is provided with a distributor 14 which is rotatably arranged at a lower end part of an introduction column 12 for introducing water to be treated and which has a blow-off pipe 20 where a blow-off port 22 for blowing off the water to be treated downward in a sedimentation tank 10 is formed, a flow blocking board 16 which is provided below the blow-off port 22 and rotates together with the distributor 14, a sludge collecting pit 30 which is arranged at a bottom of the sedimentation tank 10, a sludge discharge pipe 31 which is joined to a flank of the sludge collecting pit 30, an auxiliary rake 19 which agitates the sludge while rotating in the sludge collecting pit 30 and at least one rotary pipe 18 which has an upper port between a straight trunk part lower end of the sedimentation tank 10 and a lower surface of the flow blocking board 16 and has a lower port in the sludge collecting pit 30 and which rotates together with rotation of a rotary shaft 42.