Abstract: There is provided an apparatus for assisting hygienization of organic waste. The apparatus comprises at least one reception means for receiving organic solid matter and organic waste, mixing means for mixing the organic waste and the organic solid matter together into an organic mixture, selecting means for selecting whether to expose the organic mixture in the mixing means to either: aeration in order to create a homogenized and internally oxygenous organic mixture, thereby accelerating the hygienization of the organic mixture, or a heat treatment, wherein the heat treatment performs the hygienization of the organic mixture, or to neither the aeration nor the heat treatment. The mixing means may then expose the organic mixture to the aeration, or to the heat treatment, or to neither of the aeration nor the heat treatment on the basis of the selection. The apparatus may further comprise delivery means for passing the organic mixture to either aerobic biodegradation or an end user.

Abstract: There is provided an apparatus for assisting hygienization of organic waste. The apparatus comprises at least one reception means for receiving organic solid matter and organic waste, mixing means for mixing the organic waste and the organic solid matter together into an organic mixture, selecting means for selecting whether to expose the organic mixture in the mixing means to either: aeration in order to create a homogenized and internally oxygenous organic mixture, thereby accelerating the hygienization of the organic mixture, or a heat treatment, wherein the heat treatment performs the hygienization of the organic mixture, or to neither the aeration nor the heat treatment. The mixing means may then expose the organic mixture to the aeration, or to the heat treatment, or to neither of the aeration nor the heat treatment on the basis of the selection. The apparatus may further comprise delivery means for passing the organic mixture to either aerobic biodegradation or an end user.

Abstract: A method of producing fertilizer out of sludge, in which method sludge is heated with superheated steam for achieving hygienization to destroy pathogenic microorganisms. In the method, the sludge is heated to a temperature of 60 to 100° C. with superheated steam having a temperature of 200 to 600° C. to activate increasing of the amount of soluble carbon in the sludge and to restart biodegradation of the sludge by using non-pathogenic microorganisms still remaining in the sludge after the heating.