NOVELTY - Organic waste supplied to a processing apparatus, is simultaneously subjected to methane-fermentation process caused by methane-fermentation microbes, and denitrification process caused by microbes capable of denitrifying both ammoniacal nitrogen and nitrite, to nitrogen gas, on anaerobic conditions.    USE - For processing organic waste containing nitrogen, and sludge formed by treatment of sewage.    ADVANTAGE - Enables simultaneously performing the fermentation process and the denitrification process, without affecting the activity of the fermentation process, in a single tank. Hence reduces the installation space of the treatment apparatus, and makes the apparatus simple and compact. Enables efficient removal of ammoniacal nitrogen, by sterilizing the microbes which consume nitrite. Enables efficiently cultivating the microbes, by maintaining suitable conditions in the reactor. Enables suitably adjusting the concentration of ammonia and nitrous acid, in the waste, and performing nitrification- denitrification reaction efficiently. Prevents draining of microbes from the apparatus, by returning separated solids to the apparatus.    DETAILED DESCRIPTION - The simultaneous fermentation and denitrification is performed after sterilizing the microbes which consume nitrites present in organic waste. Water containing ammoniacal nitrogen and nitrite, is supplied to the reactor in which sludge obtained by methane fermentation process and sewage treatment process, is stored. Microbes are cultivated in the reactor, by maintaining the reactor, at normal temperature, neutral pH and anaerobic conditions. Microbes are added to the apparatus based on the amount of ammoniacal nitrogen or nitrite in the apparatus, or in the effluent which drains from the apparatus. Nitrogen oxide obtained from exhaust gas of a combustion furnace, nitrous acid, nitric acid are added to the apparatus, based on the ammoniacal nitrogen, or nitrite concentration in waste. The solid separated from the effluent is returned to the apparatus. INDEPENDENT CLAIMS are also included for the following:    (1) organic waste processing apparatus; and    (2) sludge.    DESCRIPTION OF DRAWING(S) - The figure shows the schematic view of the processing apparatus for organic waste.    microbes (1)    sludge (3)    reactor (4)    processing unit (5)    waste water (7)