NOVELTY - The plant for the production of biogas, comprises a fermenter (2) into which a nutrient medium is introduced and is fermented to produce biogas, a pressure sensor (20), which detects the pressure of the biogas present in the fermenter, a control device, which generates a signal controlling the filling quantity of the nutrient medium present in the fermenter, and a heat exchanger through which process heat required for the fermentation is introduced to the nutrient medium. A sensor signal of the pressure sensor is transmitted to a control device.    USE - Plant for the production of biogas.    ADVANTAGE - The biogas plant is simple and ensures production of biogas with less operating and maintenance costs in easy manner.    DETAILED DESCRIPTION - The plant for the production of biogas, comprises a fermenter (2) into which a nutrient medium is introduced and is fermented to produce biogas, a pressure sensor (20), which detects the pressure of the biogas present in the fermenter, a control device, which generates a signal controlling the filling quantity of the nutrient medium present in the fermenter, and a heat exchanger through which process heat required for the fermentation is introduced to the nutrient medium. A sensor signal of the pressure sensor is transmitted to a control device, which compares the actual pressure of the biogas with a rated pressure that is predetermined. The signal adjusts the supply of the nutrient medium to the fermenter and/or discharges the medium from the fermenter. The predetermined rated pressure is equal to the atmospheric pressure. The control device regulates a storage device (10) for the nutrient medium, the influx of the nutrient medium by regulating valves and/or charging pumps (31, 32) and outflow of the nutrient medium present in the fermenter by controlling valves. The fermenter has exit points for entirely or partially fermented nutrient medium present in the fermenter. The exit points are opened and closed through the controlling valves of the controlling device. The storage device upstream to the fermenter has a mixing unit in which the nutrient medium to be introduced to the fermenter and a gaseous medium are mixable and the mixture is introduced in to the fermenter. The mixing unit has a first inlet over which the nutrient medium is introduced into the mixing unit, a second inlet over which the gaseous medium is introduced into the mixing unit, and a third inlet over which the nutrient medium taken from the fermenter is introduced to the mixing unit. The biogas plant has a gas pipeline through which the biogas obtained from a gas storage area of the fermenter is introduced to the second inlet of the mixing unit. A gas compressor and/or a gas pump (13) is connected upstream to the second inlet of the mixing unit. An INDEPENDENT CLAIM is included for a procedure for pressure regulation of a biogas plant with a fermenter.    DESCRIPTION OF DRAWING(S) - The figure shows a biogas plant.    Fermenter (2)    Storage device (10)    Gas pump (13)    Pressure sensor (20)    Charging pumps. (31, 32)