NOVELTY - Treating waste material of breweries, preferably brewery grains, comprises: (i) bringing together the treated waste materials in a first storage container (13) or second storage container (33); (ii) introducing the waste materials from the first or second storage container into first reaction vessel (16); (iii) introducing the catalysts into the first reaction vessel; (iv) supplying the heat energy to the waste materials in the first reaction vessel; (v) producing excessive pressure in the first reaction vessel; (vi) removing the excessive reaction heat energy from the first reaction vessel.    USE - The brewery grain is useful as a feeding stuff and for producing biogas.    ADVANTAGE - The method: has low production cost; requires less energy; comprises treatment process which is exothermic and the excess liberated heat energy is again utilized by the entire system, thus shows high efficiency.    DETAILED DESCRIPTION - Treating waste material of breweries, preferably brewery grains, comprises: (i) bringing together the treated waste materials in a first storage container (13) or second storage container (33); (ii) introducing the waste materials from the first storage container or a second storage container into a first reaction vessel (16); (iii) introducing the required catalysts into the first reaction vessel; (iv) supplying the heat energy to the waste materials in the first reaction vessel, until the reaction comes and remains on; (v) producing excessive pressure (reaction pressure) in the first reaction vessel for carrying out the required reaction; (vi) removing the excessive reaction heat energy produced in the course of the reaction from the first reaction vessel in such a way that the reaction temperature is needed to maintain the required reaction; (vii) bringing out the reaction products from the reaction vessel, after the completion of the reaction. The waste materials from the first storage container are introduced gradually via a first pressure lock (15) at the inlet opening (17) of the reaction vessel or the waste materials from the second storage container are introduced via a feed pump (35) with reaction pressure gradually into the reaction vessel. The initially introduced waste materials in the reaction vessel are moved by the incoming waste materials of the inlet opening in the direction towards the outlet opening and thus the initially introduced waste materials are subjected to the conversion or treatment process. The reaction products are brought out via a second pressure lock at the outlet of the reaction vessel gradually from the reaction vessel such that the reaction pressure is maintained in the reaction vessel. An INDEPENDENT CLAIM is also included for a device for carrying out the above mentioned method comprising reaction vessel loaded with reaction pressure exhibiting an inlet and outlet opening, where the reaction vessel has on its outside and/or on its inside and/or in its interior space at least a heat transfer element (heat exchanger) which is connected both to a thermal energy source and to a heat sink and a first pressure lock connected to the inlet opening of the reaction vessel, by means of which the treated waste can be introduced gradually into the reaction vessel with a controlled reaction pressure and thereby gradually moved out through the reaction vessel up to the outlet opening and a second pressure lock connected to the outlet opening of the reaction vessel, by means of which the reaction products are discharged while maintaining the reaction pressure in the reaction vessel.    DESCRIPTION OF DRAWING(S) - The figures 1 and 2 show a schematic representation of a first and a second device respectively for the treatment of waste materials, with some shared parts of the device.    First storage container (13)    First pressure lock (15)    first reaction vessel (16)    Inlet opening (17)    Second storage container (33)