What is the recommended velocity for a rapid mixer in feet per second?

The recommended velocity for a rapid mixer in water treatment processes is typically set between 5 to 7 feet per second. This velocity range is optimal for ensuring adequate mixing and uniform distribution of coagulants within the water without causing excessive turbulence that could disrupt the overall treatment process. Effective mixing is crucial for promoting the agglomeration of particles and enhancing particle collision rates, which leads to better floc formation. This is essential for successful sedimentation and filtration steps later in the treatment process.

If the velocity is too low, it may not achieve the desired level of mixing and could lead to ineffective coagulation. Conversely, velocities that are too high can create shear forces that may break apart flocs and hinder the coagulation process. Thus, a velocity in the 5 to 7 feet per second range strikes a balance between effective mixing and maintaining floc stability, making it the recommended standard in water treatment operations.