NOVELTY - Collection and removal device having a stirrer that displaces the liquid over its whole height in a circular motion about a vertical central axis, is new.    USE - For suspended layers in a fermenter for the anaerobic fermentation of organic substances.    ADVANTAGE - The device is simple to produce.    DETAILED DESCRIPTION - The stirrer (12) is designed and installed so that the liquid can be displaced over its whole height in a circular motion about a vertical central axis (10). The flow speed is large enough to hold the solids (19) in the liquid in the suspension. A flow-reducing barrier (14) is arranged on the container floor against the flow direction and before the collection chamber (7) so that the flow speed is reduced behind the barrier in such a way that the solids are removed from the liquid and are collected in the collection chamber for removal. Collection and removal device (1) comprises a fermenter container (2) of a fermenter (6) for receiving liquid containing organic substances; a collection device for collecting the solids in a collection chamber (7); a removal device for removing the solids collected in the collection chamber and extending from the collection chamber up to the outside of the fermenter container; and a stirrer (12) arranged in the fermenter container for stirring and moving the liquid. The stirrer is designed and installed so that the liquid can be displaced over its whole height in a circular motion about a vertical central axis (10). The flow speed is large enough to hold the solids (19) in the liquid in the suspension. A flow-reducing barrier (14) is arranged on the container floor against the flow direction and before the collection chamber so that the flow speed is reduced behind the barrier in such a way that the solids are removed from the liquid and are collected i n the collection chamber for removal. Preferred Features: The fermenter is part of a biogas plant.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic longitudinal section through the collection and removal device.    collection and removal device (1)    fermenter container (2)    fermenter (6)    collection chamber (7)    central axis (10)    stirrer (12)    flow-reducing barrier (14)    solids (19)