Detention time in flocculation basins is usually designed for how long?

In flocculation basins, the detention time is typically designed to be between 15 to 45 minutes. This duration is crucial because it allows sufficient time for the micro-coagulated particles in the water to collide and form larger floc particles. The process of flocculation relies on gentle mixing to promote these collisions without breaking up the floc particles that might already be forming.

Within this time frame, the goal is to achieve effective aggregation of smaller particles into larger flocs that can then be easily removed in subsequent sedimentation or filtration processes. If the detention time is too short, there may not be enough opportunity for effective floc formation, while excessively long detention times could lead to floc breakage and destabilization, ultimately compromising the treatment process. Hence, the design range of 15 to 45 minutes is well-established in design practices for optimal water treatment efficiency.