| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a flocculation method which sets the turbidity at a predetermined level or less with the minimum injection amount of flocculant and permits quick correspondence with respect to an increase of suspension particles or the turbidity in water to be treated.SOLUTION: In a flocculation method, the number per unit volume of suspension particles of 0.5 to 1μm diameter in an area of front and rear regions passing through a rapid agitation tank 2 or the turbidity is measured, on the other hand, an injection amount of necessary flocculant for providing a prescribed level of turbidity in a sand filtration basin 5 is set to the minimum limit, the number per unit volume in such a case or the maximum value of the turbidity is measured and, on the treatment stage, when a measurement value at the same position as a preliminary experiment exceeds the maximum value with respect to the number per unit volume or the turbidity, further additional injection of flocculation, and/or agitation intensity, and/or an increase of agitation time is performed until the measurement value returns to the maximum value.</p> |
