Treatment of anaerobic sludge digester effluents by the CANON process in an air pulsing SBR

The reactor presented good biomass retention capacity allowing the accumulation of 4.5 g VSS L−1. The biomass was composed by ammonia oxidizing bacteria (AOB) forming fluffy structures and granules with an average diameter of 1.6 mm. These granules were composed by Anammox bacteria located in internal anoxic layers surrounded by an external aerobic layer where AOB were placed.