Research on the growth process of aerobic granular sludge under high substrate loading rate

Aerobic granular sludge taken from a sequencing batch reactor at steady state was used in this study. After aerated for 1 and 4 hours at high organic loading rate, the mixed liquid suspended solids (MLSS) concentration of granular sludge increased from 1.16 g/L to 1.48 g/L and 1.56 g/L, respectively, similar to the growth process of floc-like sludge and small granules. The number per milliliter mixed liquid of granules and flocs decreased from 283 to 201, resulted from the breakup of big granules. The mean weight of bioparticle for granules and flocs increased from 4.07 μg to 7.75 μg. During the experiment, the size distribution of sludge remained stable. Two peak values, 200 μm and 600 μm, appeared in the size distribution curve.