A case for aerobic sludge granulation: from pilot to full scale

Abstract

A pilot-scale sequencing batch reactor (SBR) treating 120 m3/d of a town's wastewater was set up in 2009 and aerobic granules with a mean diameter of 0.28 mm, mixed liquor suspended solids (MLSS) of 7,500 mg/L and sludge volume index (SVI)30 of 43 mL/g were achieved. A full-scale SBR with 50,000 m3/d for treating a town's wastewater was operated in 2010 and aerobic granules with a mean MLSS of 2,285 mg/L and SVI30 of 52.5 mL/g were obtained. Aerobic granules had excellent performances of chemical oxygen demand (COD) and NH4+-N removal and remained stable for a long time. Raw wastewater and SBR operating mode had a positive effect on aerobic granule formation. Therefore, aerobic granular technology could be successfully applied in the full-scale bioreactor under specific conditions. Future development of aerobic granular technology is the application in full-scale continuous-flow reactors.