DEPHOSPHORIZER

PROBLEM TO BE SOLVED: To provide the dephosphorizer for settling a phosphorus component as ammonium magnesium phosphate and substantially removing phosphorus. SOLUTION: A phosphorus-contg. water is aerated in the presence of magnesium ion and ammonium ion to form the crystal of ammonium magnesium phosphate in this aeration tank. The port for supplying the phosphorus-contg. water provided in the aeration tank, a means for adding a magnesium salt, a means for discharging the phosphorus-free water furnished at the upper end, an air injecting means furnished close to the bottom to form crystals as a fluidized bed and a port for discharging the grown crystal furnished below the air injecting means are provided.