OPERATION OF TWO-STAGE ACTIVATED SLUDGE CIRCULATING MODIFICATION INCREASED IN NITROGEN REMOVING RATE

摘要

PURPOSE: To provide an operating method capable of accelerating denitrificating reaction and increasing nitrogen removing rate by maintaining an anaerobic state in latter stage anaerobic vessel good in a two-stage activated sludge circulating modification. ;CONSTITUTION: In a constitution in which a second denitrification vessel 1c and a second aerobic vessel 2b are connected in series to a first denitrification vessel 1b for executing denitrification and a first aerobic vessel 2a for executing nitrification and sludge return pumps 8a and 8b for returning a part of the sludge discharged from the last settling tank 7 to the first and second denitrification vessels 1b and 1c are provided, an ATU-Rr meter 14 is provided at the first aerobic vessel 2a to decide the state of progress of the nitrificating reaction in the first aerobic vessel 2a. When the nitrificating reaction is over, a sludge amount returned to the second denitrification vessel 1c through the second sludge return pump 8b is increased to maintain the anaerobic state in the second denitrification vessel 1c good so as to accelerate the denitrificating reaction and the nitrogen removing rate is improved.;COPYRIGHT: (C)1996,JPO