DISPOSITIF POUR LA FILTRATION ASCENDANTE DES EAUX RESIDUAIRES A LIT GRANULAIRE MULTI-COUCHES

摘要

Waste water are purified biologically in an upward flow immersed filter bed. The bed (1) consists of a number of layers of granular material (3a-e) of decreasing particle size in the direction of flow, supported on a perforated support floor (2). Water for treatment is fed (4) to the space (6) beneath the floor, together with an air supply (5) for use during treatment and cleaning of the filter. A second supply of air or oxygenated gas (15) is positioned 0.5-3 m above the perforated floor. Treated liquid is removed from the top (7) of the filter and back-washing liquid removed from the base (8).