STUDY ON GRANULATION OF ACTIVATED SLUDGE USING SEQUENCING BATCH AIRLIFT REACTOR FOR COD AND AMMONIA REMOVAL

Abstract

Synthetic wastewater with glucose as carbon source was used for cultivation of aerobic granules in sequencing batch airlift reactor (SBAR). Grinded shell powder with diatmeter of 150-200 um used as carrier. SBAR was run at hydraulic retention time (HRT) 5.1 hours, airflow of 4 liters/m and airlift velocity of 4.2 cm/s. The experiment was run at two organic loading rates (OLRs). They were 2.6 and 5.2 kg COD/m°.day, corresponding to influent COD and N-ammonia of 600; 1200 mg/l and 26; 60 mg/l, respectively. After 61 days of running, aerobic granules with size of 1,0-1,2 mm are formed. The size of granules increased to 5 mm at 80th day. Aerobic granules had settling velocity of 36-56 m/h, SVI of 11,4-44.2 ml/g. COD and N-ammonia removal of SBAR were greater than 96% and 75-90%, respectively. It was found that nitrification and denitrification occurred simultaneously in granules.' The COD and N-animonia of SBAR decreased to 70% and 51%, respectively when filamentous sludge bulking and viscous bulking appeared simultaneously.