Investigation on the formation and kinetics of glucose-fed aerobic granular sludge

Aerobic granular sludge was cultivated in a glass sequencing batch reactor (SBR) with glucose synthetic wastewater. The spherical-shaped granules with the mean diameter of 0.1 mm were observed on the 4th day. With the increase of chemical oxygen demand (COD) concentration of the influent, aerobic granules matured, the size of which ranged from 1.2-1.9 mm. The aerobic granular sludge could sustain high organic loading rate (about 4.0 g COD/(L d)) with good settling ability (settling velocity 36 m/h) and high biomass concentration (MLSS 6.7 ± 0.2 g/L). Experimental data indicated that the substrate utilization and biomass growth kinetics followed Monod's kinetics model approximately. The corresponding kinetic coefficients of k (maximum specific substrate utilization rate), Ks (half velocity coefficient), Y (growth yield coefficient) and Kd (decay coefficient) were 13.2 d−1, 275.8 mg/L, 0.183-0.250 mg MLSS/mg COD and 0.023-0.075 d−1, respectively, which made aerobic granules to have short setup period, high rate of substrate utilization and little surplus sludge.