NOVELTY - The method comprises: introducing a substrate to be fermented; re-circulating the fermented material directly inside a fermenter through stacks immersed in different locations of the fermenter; injecting a large amount intermittent, short, gas pressure into conduits (9) divided into a mixing zone throughout the fermenter to achieve homogenization and the flow of the material; separating a hydrolysis acidogenic phase and a methanogenic phase via a partition wall (3); and channeling the material at 2 degrees by a wall of the fermenter according its geometry.    USE - The method is useful for performing an medium degradation such as continuous fermentation of solid substrates in high solids concentration in a fermenter of a closed tank of variable geometry (claimed) for reducing the organic matter and producing energy in the form of biogas, where the substrate is a waste including a household food waste, a waste from sewage treatment plants, and urban, industrial and agricultural wastes.    ADVANTAGE - The method is capable of economically performing the continuous fermentation of solid substrates in a simple manner.    DETAILED DESCRIPTION - The method comprises: introducing a substrate to be fermented; re-circulating the fermented material directly inside a fermenter through stacks immersed in different locations of the fermenter; injecting a large amount intermittent, short, gas pressure into conduits (9) divided into a mixing zone throughout the fermenter to achieve homogenization and the flow of the material; separating a hydrolysis acidogenic phase and a methanogenic phase via a partition wall (3); and channeling the material at 2 degrees by a wall of the fermenter according its geometry leading to improved gas productivity and controlled degradation. The gas injection step allows the flow of the thick material that is homogeneous and channeled between introduction points (10) and extraction points (11) of the material to be fermented. The step of introduction and the step of recirculation of the fermentation material extracted by gravity in various places of the fermenter and recirculated within a boundary of the fermenter by a pump are carried out by the conduits within the boundary of the fermenter. The method further comprises: a step of massive gas injection into a ceiling of the fermenter through the conduits, where the conduits are activated at the same time creating an intense, swirling and sequential mixing of the fermentation material for a continuous flow of the material; a step of supplying the gas at a pressure of 3-5 times greater than a pressure of a height of a column of the material in the stacks rapidly pushing the material to a point bottom of the conduits and at a thrust generating a reversal of the vortex material in an effective range of square meters; and a step of controlling the type of installation, size, geometry, and the nature of the substrates using an automated microprocessor. The gas injection step sequentially covers the whole of the fermenter and a level of homogenization of the material in the fermenter. Intermittency between the mass gas injection and a recompression of biogas in a storage box at a pressure followed by a further injection of pressure gas in another area to use a booster with low power, release time and time compression is in a ratio of 100. An aerobic pre-fermentation is carried out in a compartment through the air injection in the appropriate stacks through the configuration of the partition wall from a roof of the fermenter. The material in the compartment undergoes enzymatic hydrolysis to optimize the enzymatic action of the material favorable to a bacterial attack to increase its level of degradation and limit the residence time in the fermenter. The controlling step comprises: differentially activating an opening or closing of the gas valves or the recirculation pump of thick material; and controlling the mass flows of the material to determine the quantity of recirculation of the fermentation or fermented material at points determined by the conduits of the fermenter according to parameters of balance characteristics of the fermentor and substrate to be fermented.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a fermenter.    Methanogenesis compartment (2)    Partition walls (3)    Conduits (9)    Introduction points (10)    Extraction points. (11)