Water filtration

A method used for passing water through a bed of filter material to improve its quality.

Removal of suspended solids from a fluid (according to their particle size). Gravity or pressure filtration can be carried out through a porous wall (screen, membrane) or through a granular material (sand, anthracite, gravel and other materials used in biofiltration). One distinguishes screening (0.15-2.5 mm), micro-screening (25-150 μm), microfiltration (1-100 μm), ultrafiltration (1 - 0.1 μm) or nanofiltration (10 - 100 nm) depending on the size of the retained particles or the pores of the device.