TREATMENT METHOD OF WASTE WATER CONTAINING NITROGEN

摘要

A wastewater treatment method capable of improving removal efficiency of total nitrogen contained in wastewater and an apparatus for treating wastewater containing nitrogen that is operated according to the wastewater treatment method are provided. A treatment method of wastewater containing nitrogen comprises the steps of: performing first denitrification of raw wastewater by passing raw wastewater through a denitrification tank(5) and nitrification tanks(6) that are at a volume ratio of 1:1 when a concentration of thiocyanate(SCN) contained in raw wastewater is less than 500 ppm, and performing first denitrification of raw wastewater by passing raw wastewater through a denitrification tank and nitrification tanks that are at a volume ratio of 1:3 when a concentration of thiocyanate(SCN) contained in raw wastewater is 500 ppm or more; and additionally adding raw wastewater to the first denitrified wastewater to perform second denitrification of the wastewater. The raw wastewater is added to the first denitrified wastewater during the second denitrification in an amount of 5 to 20 vol.% relative to the total flow amount of raw wastewater flown into the wastewater treatment process.