NOVELTY - Wastewater (5) containing ammoniacal nitrogen, phosphorus, is dephosphorized to form magnesium-ammonium phosphate. Effluent of dephosphorizing process is supplied to main, sub denitrification units (2,3) where ammoniacal nitrogen, nitrate, nitrite, are denitrified in presence of autotrophic nitrifying bacteria, autotrophic denitrification microbes, and autotrophic denitrification microbes, respectively.    USE - For processing wastewater containing ammoniacal nitrogen and phosphorus, such as wastewater obtained during processing of sludge produced in sewage disposal plant, for recovering nitrogen and phosphorus.    ADVANTAGE - Enables efficiently recovering large amount of phosphorus, while reducing the amount of treating-chemicals used, and the level of aeration of the wastewater, by combining the physiochemical dephosphorizing process with the denitrification process using microbes.    DETAILED DESCRIPTION - The effluent is treated in the denitrification units, in mild aerobic condition and intermittent aeration conditions, to generate nitrogen gas. The effluent obtained in the main denitrification tank is treated in the sub denitrification tank. The pH of wastewater is set to 7.5-9.5 in the dephosphorizing unit (1) having a solid-liquid separator for separating produced magnesium-ammonium phosphate, from waste water. The effluent of the dephosphorizing process, contains 100 mg/l or more of ammoniacal nitrogen, and 3 mg/l or more of magnesium ion. The treated water obtained in the sub denitrification unit is returned to the dephosphorizing process or to the waste-water feed pipe.    An INDEPENDENT CLAIM is also included for processing apparatus of waste water containing ammoniacal nitrogen and phosphorus.    DESCRIPTION OF DRAWING(S) - The figure shows the explanatory view of the processing method of water containing ammoniacal nitrogen and phosphorus. (Drawing includes non-English language text).    dephosphorizing unit (1)    main and sub denitrification units (2,3)    solid-liquid separator (4)    wastewater (5)