NOVELTY - The compact biogas container comprises fermentation- and functional tank, an external wall (2), an air lock (10) arranged at the center of the biogas tank, an overflow funnel (3) intended at a certain distance from the air lock, and a domed roof. The entire biogas container is built in the form of self-contained, concentric spatial structure. The external wall is built in the form of an annular ring around the container by a variable number of perpendicularly standing tanks (5) arranged in cylindrical, palisade-shaped fashion.    USE - For the production of hydrocarbon gases through fermentations of materials occurring in the agriculture.    ADVANTAGE - The biogas container is cost effective, has more compactness with floor space saving, is manufactured in a simple manner, and ensures different process steps for the biogas production in only one container.    DETAILED DESCRIPTION - The compact biogas container comprises fermentation- and functional tank, an external wall (2), an air lock (10) arranged at the center of the biogas tank, an overflow funnel (3) intended at a certain distance from the air lock, and a domed roof. The entire biogas container is built in the form of self-contained, concentric spatial structure. The external wall is built in the form of an annular ring around the container by a variable number of perpendicularly standing tanks (5) arranged in cylindrical, palisade-shaped fashion. The tanks are connected via special connecting elements (4), which are connectably put into one another like in a piano hinge. A self-contained and sealed tank wall results by special sealing elements (9) between the perpendicular tanks. The domed roof segment is formed at the airlock and covers the double annular space formed by the overflow funnel by a clamping ring. The double annular space lies at the external wall and is connected there with a runway. The tanks are set up perpendicularly at a work plane during assembly. A screw-shaped element serves for the height adjustment and the tanks are locked and/or durably fastened by a concrete gate. The connection elements are formed as continuous loops and are placed at a distance to one another resulting from a number corresponding to the respective pressure ratios and a band thickness around the wall of the tanks. The formed loops are perpendicularly locked by penetrated bar- or bolt-shaped elements, or the loops are locked by concrete joint sealing compounds. The connection elements are placed repeatedly around the respective tanks and form a corset stabilizing the tanks. The tanks, the airlock, the overflow funnel and the domed roof are made from chemical-resistant glass-fiber reinforced plastic (GRP) material with a loadable structure and arrangement of the fibers. The domed roof is curved or double-curved, self-supporting roof, which is double-shelled and is intended with integrated thermal insulation. The segment-like overflow funnel is made from funnel elements with stabilizing wave profile and assembly flanges and exhibits an overflow collar at its top margin. A clamping ring carrying the roof members of the domed roof is arranged at the airlock. The tanks are equipped with spherical segment elements for the head and floor area. For the placement of the domed roof on the circularly enclosing external wall, a peripheral tie beam is intended, which represents the inspection course and the rainwater discharge spout.    DESCRIPTION OF DRAWING(S) - The figure shows a compact biogas container:    External wall; (2)    Overflow funnel; (3)    Connecting elements; (4)    Perpendicularly-standing tanks; (5)    Sealing elements; (9)    Air lock. (10)