Abstract: The method of producing aerobic biogranules for the treatment of waste water comprising the steps of: a) introducing waste water into a reactor; b) seeding the reactor with a active biomass material; c) supplying the oxygen-containing gas to the reactor to provide a mixing action to the suspension of biomass material in said waste water, the supply of oxygen-containing gas providing a superficial upflow gas velocity greater than 0.25 cm/s; d) initiating a period of nutrient starvation of the biomass material while continuing to supply oxygen-containing gas; e) allowing formed aerobic granules to settle in a settling zone in said reactor; f) discharging at least a portion of the waste water; g) repeating steps (a) to (f) until at least a portion of the biogranules in said settling zone are within a predetermined properties; and h) recovering said biomass granules within those predetermined properties.