NOVELTY - The method for producing biogas e.g. methane by anaerobically decomposing solid biomasses in a biogas plant, comprises introducing the biomass into a process liquid of a fermenter (2) on the filler side and floatably guiding by continuous or discontinuous spraying with the liquid, and transferring a fermenting residue at the fermenter end to a fermenting residue filter (4), which is operated as an integrated component of the biogas plant as anaerobic filters; is continuously or discontinuously sprayed with the process liquid, and produces biogas by partial decomposition of the liquid.    USE - The method for producing biogas e.g. methane by anaerobically decomposing solid biomasses in a biogas plant, where the biomasses are organic matter, such as renewable raw materials, dung, silage, garden wastes and food wastes.    ADVANTAGE - The method ensures continuous and economical decomposition of the biomass for methane gas production and effectively secures the fermenting waste in a compact biogas plant in a clean and safe manner.    DETAILED DESCRIPTION - The method for producing biogas e.g. methane by anaerobically decomposing solid biomasses in a biogas plant, comprises introducing the biomass into a process liquid of a fermenter (2) on the filler side and floatably guiding by continuous or discontinuous spraying with the process liquid, and transferring a fermenting residue at the fermenter end to a fermenting residue filter (4), which is operated as an integrated component of the biogas plant as anaerobic filters; is continuously or discontinuously sprayed with the process liquid, produces biogas by partial decomposition of the structural organic material and the dissoluble organic compounds in the liquid, and creates a self-cleaning filter system by the discharge of the fermenting residue at the base of the filter. A spraying device (6) removes the bacteria-containing liquid at the base of the filter and from the fermenter by waste-water pumps and the biogas is obtained in a gas-storage (8). The process liquid is guided over the filter or directly removed from the fermenter. The biomasses flow as a functional unit through the fermenter and the filter. The process is carried out at mesophilic and thermopile temperatures. The fermenting residue in the filter takes over due to the relative large surface of the function of the filter materials. Organic masses are reduced in the filter. The fermenting residue is supplied to the filter and a constant filter cleaning takes place via the near-surface removal. The fermenting residue is drained in the discharge and the separated process liquid is supplied into the fermenters or the filter. The withdrawal of the process liquid takes place at the fermenter discharge, at the base of the filter and at the fermenting residue discharge. The process liquid is removed at different parts of the fermenter and is supplied to the filter. An INDEPENDENT CLAIM is included for a device for the biogas production by anaerobically decomposing solid biomasses.    DESCRIPTION OF DRAWING(S) - The diagram shows a device for the biogas production (Drawing includes non-English language text).    Fermenter (2)    Filter (4)    Spraying device (6)    Base filter (7)    Gas storage. (8)