BIOLOGICAL NITRIFICATION DENITRIFICATION TREATMENT SYSTEM AND DENITRIFICATION TREATMENT METHOD

摘要

PROBLEM TO BE SOLVED: To treat a nitrogen component included in waste water which cannot be treated by an existing activated sludge method only with simple and supplementary facilities. SOLUTION: The nitrogen component which cannot be denitrified in a biological treatment tank I is highly denitrified in a biological denitrification treatment tank II by connecting the biological denitrification treatment tank II packed with a sulfur-carbonate inorganic material and mainly having autotroph to the poststage of the biological treatment tank I for carrying out nitrification denitrification treatment by combining a nitrification treatment tank Ia with a denitrification treatment tank Ib and with bacteria which belong to heterotroph. Then, at the prestage of the biological treatment tank I, an adjustment tank P for uniformly pre-mixing the waste water is provided, and a BOD component is supplemented so as to keep a ratio of the concentration of the BOD component BA (mg/L) to the concentration of the nitrogen component TNA (mg-N/L) included in the waste water 3 flowing in the biological treatment tank I for carrying out nitrification denitrification treatment at 5