Printing and dyeing wastewater denitrifying technology

The invention relates to a printing and dyeing wastewater denitrifying technology, and belongs to the technical field of biological treatment to water, wastewater or sewage. In the printing and dyeingwastewater denitrifying technology, a treatment tank and a sedimentation tank are used, wherein the sedimentation tank is positioned at the tail end of the treatment tank; two anaerobic zones and four aeration zones are sequentially arranged inside the treatment tank; a water inlet of the treatment tank is formed in the anaerobic zones; a reflowing pipe is arranged inside the sedimentation tank;the other end of the reflowing pipe is connected to a starting position of the aeration zones; the anaerobic zones have the dissolved oxygen content of 0.2 mg/L or below; the aeration zones have the dissolved oxygen content of 2.0-4.0 mg/L; water to be treated is sequentially treated by the two anaerobic zones, then enters the aeration zones together with reflowing sludge so as to complete aeration, then is sent into sedim