NOVELTY - Reprocessing solid organic waste and wastewater obtained during vegetable oil production, comprises e.g. crushing the solid organic waste and mixing with the wastewater in a stirred and heated reactor to form a suspension, heating the suspension to at least 170 degrees C and maintaining at elevated pressure for at least 0.5 hours, in which the solid organic waste is converted to carbon-rich solid, absorbing oil from the obtained carbon-rich solid, cooling the suspension, and removing the suspension from the reactor and separating it into a solid- and wastewater fraction.    USE - The carbon-rich solid is useful as a fuel, which is used separately or as a mixture with other fuels. The reprocessed wastewater is useful for irrigation of plants, preferably oil plants, where the reprocessed wastewater is previously neutralized with potassium hydroxide (all claimed).    ADVANTAGE - The method: makes use of simple devices and thus it can be carried out even at the place of oil plantations; operates uniformly; and exhibits high conversion rate of biomass.    DETAILED DESCRIPTION - Reprocessing solid organic waste and wastewater obtained during vegetable oil production, comprises: crushing the solid organic waste and mixing with the wastewater in a stirred and heated reactor to form a suspension; adjusting the pH of the suspension to acidic range; removing the atmospheric oxygen from the reactor by flushing with inert gas; sealing the reactor in a gas-tight manner; heating the suspension to at least 170 degrees C and maintaining at elevated pressure for at least 0.5 hours, in which the solid organic waste is converted to carbon-rich solid; crushing the emulsion of wastewater and vegetable oil residues; absorbing oil from the obtained carbon-rich solid; cooling the suspension; and removing the suspension from the reactor and separating it into a solid- and wastewater fraction. The solid waste comprises pressing residues of oleaginous fruits or oilseeds and the wastewater in addition to other organic impurities comprises vegetable oil residues that are present in emulsified form in the wastewater.