suspended solids meet and adhere together into large masses. This gentle agitation is
essential for flocculation to be accomplished either hydraulically or mechanically. The
most common hydraulic method is a baffled flocculation basin (see figure1-3) in which
the water flows around the end of, or over and under, the baffles. A disadvantage in the
use of baffles is that the degree of agitation is dependent upon the water velocity and is
not easiIy controlled. The trend is toward mechanically driven paddles whose speed
can be adjusted to give the optimum degree of agitation (see figure1-4).
Figure 1-3. Battle flocculation basin.
Figure 1-4. Paddle type flocculator.
d. Sedimentation. Sedimentation is the process of removing settleable
materials. It is accomplished by decreasing the velocity of flow to lessen the ability of