Raw recycled water enters the “KROFTA” AIR DISSOLVING TUBE tangentially at one end, pressurized
to 4-6 bar, which is discharged at
the opposite end. During the short passage the water rotates in side the tube and passes repeatedly by an
insert which is fed by compressed
air. Very thorough mixing under pressure dissolves the air in the water which is released to atmospheric pressure in the floatation cell. Suspended solids flocculated with the help of flocculants attach themselves to the air bubbles and come to the surface to form the sludge.

The patented “KROFTA” SPIRAL SCOOP takes up the floated sludge, pouring it into the stationary centre section, from where it is discharged by gravity, either for recycling or disposal.

Clarified water is removed through extraction pipes which are connected to the moving centre section. Part of the clarified water passes through the “KROFTA” AIR DISSOLVING TUBE before joining the mainstream of unclarified water. The clarified water extracted from the process normally contains less than 30 ppm of suspended solids. It can be recycled in the process or sewered.

Wiper blades attached to the moving distribution duct scrape the bottom and the sides of the tank and discharge the settled sludge into the built in sump for periodic purging.