NOVELTY - The wastewater-treating equipment has a micro nano-bubble generation tank (1), a micro nano-bubble adhesion tank (2), a nitrification tank (3), lower inlet tubes (I,II) (14), a de-nitrification tank (4), an aerator, and a re-aerator (5). The micro nano-bubble generation tank produces micro nano-bubbles in introduced water. The micro nano-bubbles-containing water is adhered with microorganism sludge in the adhesion tank. The microorganisms sludge from the adhesion tank and nitrogen-containing wastewater are nitrified, denitrified and aerated.    USE - Equipment is used for treating nitrogen-containing wastewater containing organic fluorine-type surfactant, perfluorooctane sulfonic acid, or perfluorooctane acid (claimed).    ADVANTAGE - The equipment has improved microorganism-processing capacity, and attains stabilization and activation of microorganisms. The hydrogen donor is effectively decomposed in the re-aerator. Foaming in nitrification tank and re-aerator is prevented. The equipment provides treated water having excellent transparency.    DETAILED DESCRIPTION - The wastewater-treating equipment has a micro nano-bubble generation tank (1), a micro nano-bubble adhesion tank (2), a nitrification tank (3), lower inlet tubes (I,II) (14), a de-nitrification tank (4), an aerator, and a re-aerator (5). The micro nano-bubble generation tank produces micro nano-bubbles in introduced water. The micro nano-bubbles-containing water is adhered with microorganism sludge in the adhesion tank. The microorganisms sludge from the adhesion tank and nitrogen-containing wastewater are introduced into the nitrification tank filled with filler (13) for micro nano-bubble adhesion while having a water-depth of 7 m or more, and wastewater is nitrified. Inlet tube (I) installed in the nitrification tank has a discharge hole for discharging the microorganism sludge introduced into the lower portion from the inlet, and the wastewater at the lowest portion of the nitrification tank. The nitrification tank has an inlet through which microorganism sludge and wastewater are introduced into the upper end. Nitrified water is introduced to the denitrifying tank filled with a filler for micro nano-bubble adhesion while having a water-depth of 7 m or more, a hydrogen donor is added, and water is denitrified. Inlet (II) installed in the de-nitrification tank has a discharge hole for discharging to-be-processed water introduced into the lower portion from the inlet at the lowest portion of the de-nitrification tank. The de-nitrification tank has an inlet from which nitrified water is introduced into the upper end. The denitrified water is aerated in the aerator, and the re-aeration tank decomposes the hydrogen donor in the denitrified water by microorganisms.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of the wastewater-treatment equipment. (Drawing includes non-English language text)    Micro nano-bubble generation tank (1)    Micro nano-bubble adhesion tank (2)    Nitrification tank (3)    De-nitrification tank (4)    Re-aerator (5)    Filler (13)    Lower inlet tube (14)