Effect of Feed Cycle on Aerobic Granule Production in SBR system

The objective of this research was to study the effect of feed cycle on aerobic granule production in SBR system. Wastewater was a mixture of treated effluent from an ethanol factory and sugar. Average COD and BOD concentrations were 1,998 and 374 mg/L, respectively. Seed sludge was brought from an aeration tank of an activated sludge system treating municipal wastewater. Two SBR systems were used; the SBR 1 was controlled at feed cycle of 4 hours per batch while the SBR 2 was controlled at 6 hours per batch. Each reactor had volume of 8 liters fed with an organic loading rate of 0.90 - 1.08 kilogram BOD per cubic meter per day. It was found that COD removal efficiencies of SBR 1 and SBR 2 were 66.97 % and 65.36 %, respectively. For TKN removal efficiencies, they were 47.12 % and 49.04 %, respectively. Most of aerobic granules in both SBRs were larger than 0.85 millimeters. Maximum settling velocities of granules from SBR 1 and SBR 2 were 128.1 and 156.5 meters per hour, respectively.

Keywords : feed cycle; aerobic granule; SBR system; COD and TKN removal