The millions of tiny air bubbles in the Float-Treat® thickeners float solids to the tank surface, forming a highly concentrated sludge blanket.  The compacting effect of the continuous supply of air bubbles results in a sludge concentration much greater than normally obtained by gravity sedimentation.  Skimmers remove the thickened sludge at the end of the tank for disposal.

An important principle is the introduction of air into an external liquid source, such as recirculated effluent.  The recycled liquid is pumped at elevated pressure to a saturation tank where air is introduced.  Microscopic air bubbles are formed as the pressure of this stream is reduced just before re-entry into the flotation compartment.