Patent attributes
A coagulation sedimentation process for water to be treated in which an inorganic coagulant used in a purified water treatment system is limited, and remaining micro flocks and flocks are made greater in density and finer in particle size, thus obtaining clear water better in quality and reducing the amount of sludge production, including a micro flocculation step for micro-flocculating in advance fine suspended particles in water to be treated, a flocculation step for the micro flocks, and a sedimentation separation step for the flocks, in which as a final stage of the flocculation step, a flock-forming inclined plate whose pitch width is from 5 mm or more to 50 mm or less is provided, and an inorganic coagulant is limited so that the turbidity of the water to be treated after passage of the inclined plate at a ratio to that before passage is 4/5 or less.
