Abstract: A system for biologically treating wastewater comprising a rotating drum disposed within a tank. Biofilm carriers are contained in the drum. One or more hollow tube aerators are secured inside the drum to a perforated wall that forms a part of the drum. As the drum is rotated within the tank, the mixing of the biofilm carriers with the wastewater therein and the action of the hollow tubes aerates the wastewater in the rotating drum.

Abstract: System (1) for the biological treatment of wastewater comprising a tank (10) comprising a point for the entry (11) of water to be treated and a point for the exit (12) of treated water; a rotating drum (20) defining an internal volume, said drum being capable of rotating about a horizontal shaft (200) and having a wall (21) that is at least partly permeable to water, said rotating drum being disposed the tank and being intended for partial submersion in the water contained in the tank, less than half of its internal volume bathing in the water contained in the tank; a driving means (30, 31, 32) intended for driving the drum in rotation along the horizontal shaft; free media (15), having a surface suited to the development of a biofilm, disposed within the drum (20) and retained by the wall of this drum, the free media occupying a volume ranging from 30% to 80% of the internal volume of the rotating drum; at least one hollow tube (40) extending in parallel to the horizontal shaft fixed to the wall of the rotat