Flocculation is primarily achieved through which method?

Flocculation is primarily achieved through slow stirring, which allows for the gentle mixing of water and the coagulant. This process encourages finer particles in the water to collide and stick together, forming larger aggregates known as flocs. These flocs are heavy enough to settle out during the sedimentation phase, thereby clarifying the water.

Rapid mixing, while essential for the initial dispersion of coagulants, does not facilitate the slow-moving interactions necessary for floc formation. High-pressure filtration is a physical separation process that occurs after flocculation, and ultrasonic waves are typically used in specialized applications rather than standard flocculation processes. Thus, slow stirring is the method that most effectively promotes the aggregation of particles into larger flocs.