Abstract: The invention relates to a bioreactor having a tank with at least one bioreactor compartment containing a carrier medium, on the surface of which a biofilm may grow; wherein the first longitudinal end of the compartment comprises an inlet, and the second longitudinal end of the compartment comprises an outlet. The bioreactor comprises an aeration device for supplying reaction gas required for the purification process, and for agitating the carrier medium and the water to be purified into a rotary motion inside the compartment. A perforated pipe is arranged within the bioreactor compartment at a distance from the inner walls of the compartment. Inside the perforated pipe is a closing. Guide plates are arranged outside the perforated pipe, which guide water to be purified into the bioreactor space outside the perforated pipe.

Abstract: The invention relates to a bioreactor having a tank (1) with at least one bioreactor compartment (1a-1c) containing a carrier medium, on the surface of which a biofilm may grow, supply means for supplying the water to be purified into the bioreactor compartment (1a-1c) from the first longitudinal end of the compartment, discharge means at the second opposite longitudinal end of the compartment (1a-1c) for discharging the processed water from the compartment, means (7) for supplying the reaction gas required for the purification process into the bioreactor compartment, and means for agitating the carrier medium and the water to be purified into a rotary motion inside the compartment.