4. Pressure profiles

4.1 Calculating pressure drop

Most clarifications are carried out at a constant flow rate (4 to 20 m ³ /h per m ² of filter). The flow regime is laminar. At the start of filtration, when the bed is clean, the pressure drop dp _o across a small element of thickness dz can be calculated by Darcy's equation.

The pressure drop increases with increasing retention $\sigma$ . Although numerous equations have been proposed