METHOD FOR REMOVING NITROGEN AND COD COMPONENT FROM AMMONIACAL LIQUOR

PROBLEM TO BE SOLVED: To improve the removal efficiency of high concentration ammonia nitrogen and COD components contained in ammoniacal liquor by biological treatment in comparison with the conventional method. SOLUTION: The concentration of COD components that can be biodegraded by denitrifying bacteria is obtained by a biological nitrification-denitrification method. The amount of nitrite nitrogen that can be denitrified in an anoxic tank is estimated from the concentration of the COD components, and at the same time, the amount of nitrite nitrogen generated in an aerobic tank is estimated from the concentration of ammonia nitrogen and alkalinity in the ammoniacal liquor. The necessity of addition of the biodegradable COD components to the anoxic tank and the necessity of pH control in the aerobic tank are determined from the two estimated amounts to select one among treatments where the addition of the biodegradable COD components to the anoxic tank and the pH control in the aerobic tank are not performed, a treatment where the addition of the biodegradable COD components to the anoxic tank and the pH control in the aerobic tank are performed, and the treatment where only the addition of the biodegradable COD components to the anoxic tank is performed. Nitrogen in the ammoniacal liquor is removed by reaction with the COD components. COPYRIGHT: (C)2009,JPO&INPIT