Advanced sludge reaeration process improving denitrification rate for nutrient removal

摘要

PURPOSE: An advanced sewage treatment system including sludge reaeration tank for improving denitrification rate is provided, which can control aerobic sludge retention time at aerobic tank by adopting alternative aeration tank, remove nitrate by endogenous denitrification at anoxic tank in case that C/N ratio of influent wastewater is low, thus enhancing removal efficiency of total nitrogen. CONSTITUTION: The system comprises a reaeration tank(9) into which sludge is introduced via recycle line for sludge reaeration; a primary deoxygenation tank(1) into which effluent from the reaeration tank and a portion of raw wastewater are introduced, and where dissolved oxygen and nitrate are removed; an anaerobic tank(2) into which effluent from the primary deoxygenation tank and a balance of raw wastewater are introduced, and where phosphorus release is observed; an anoxic tank(3) into which effluent from the anaerobic tank and effluent from secondary deoxygenation tank are introduced, and where denitrification is observed; an alternative aeration(4) where nitrate is removed by endogenous denitrification under anoxic condition in the case that C/N ratio of wastewater is low; an aerobic tank(5) into which effluent from the alternative aeration is introduced to conduct nitrification under aerobic condition; and a secondary deoxygenation tank(6) in which effluent from the aerobic tank is introduced to strip dissolved oxygen.