Abstract: The present invention relates preferably to ways of biologically treating liquids, and devices applicable in this respect. Processes and devices according to the present invention preferably relates to a system for biological treatment of liquid such as water, the system typically comprising a container having first and second gas supplies for creating a first and second circulating flow of liquid and bio-film carriers and preferably also for aerating the liquid. Preferred embodiments of a container according to the invention comprises an outflow channel extending along, and preferably throughout, a perimeter of an upper part of the container, the flow channel having a fluid penetrable wall section facing inwardly so that fluid may flow from the interior of the container, through the fluid penetrable wall section and into the outflow channel, and an outlet for leading fluid out from the outflow channel.

Abstract: The present invention relates preferably to ways of biologically treating liquids, and devices applicable in this respect. Processes and devices according to the present invention preferably relates to a system for biological treatment of liquid such as water, the system typically comprising a container having first and second gas supplies for creating a first and second circulating flow of liquid and bio-film carriers and preferably also for aerating the liquid. Preferred embodiments of a container according to the invention comprises an outflow channel extending along, and preferably throughout, a perimeter of an upper part of the container, the flow channel having a fluid penetrable wall section facing inwardly so that fluid may flow from the interior of the container, through the fluid penetrable wall section and into the outflow channel, and an outlet for leading fluid out from the outflow channel.

Abstract: The present invention relates to biological treatment and devices applicable in this respect. The closed container comprises a first inlet (20) and a first outlet (18), at least one vertically orientated tube (6) arranged in the container (2), the lower end of said tube being raised above the bottom of the container (2), a first gas supply (8) arranged at the lower end of said tube (6) for creating a first circulating flow (F1) of liquid and microfilm carriers through the vertically orientated tube, a second gas supply (16) arranged at the bottom and in the vicinity of the wall of the container for creating a second circulating flow (F2) of liquid and microfilm carriers. The invention additionally relates to a plurality of serially connected containers.