Hydrodynamic Properties of Aerobic Granules Cultivated on Phenol as Carbon Source

The cultivation and hydrodynamic properties such as morphology, fractal dimension, porosity, size distribution, and settling velocity of stable aerobic granules, developed in a column type sequencing batch reactor SBR was investigated in this study. A column type SBR was operated with organic loading rate of 1.8 kg phenol/m3day with phenol as a sole carbon source. The granules were fractal and porous aggregates and had a fractal dimension and porosity of 2.47 and 0.7-0.9 respectively. The settling velocities of aerobic granules were in the range of 2.38x10-02m/s-7.1x10-02m/s. This was in good agreement with the settling velocities predicted by Stoke's law for porous but impermeable spheres. This may be due to the EPS (Extracellular Polymeric Substances) produced by bacteria form a gel matrix that clogs the pores within the granules which resulted in reduced permeation and settling velocities.