Course: BFM 203 Water Treatment and Control

Lecture

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Sizing a Clarifier

All clarifiers require contact/detention or settling time. Parameters for these times is between 1.4 and 4 hours. Always use the "worst case scenario" for calculations.

Settling Velocities
Particle Type | Specific Gravity | Settling Velocity
Sand, silt, and clay | 2.65 | 6.9 x 10 ^-1 cm/second
Alum and Iron flocs | 1.002 | 8.3 x 10 ^-2 cm/second
Wastewater Organics | 1.0 - 1.2 | 4.2 x 10 ^-2 cm/second
Activated sludge particles | 1.005 | 2 x 10 ^-1 cm/second