Benjamin Yan-Pui Moy
Characteristics of aerobic granular sludge in a sequencing
batch reactor with variable aeration
Received: 1 September 2005 / Revised: 29September 2005 / Accepted: 4 October 2005 / Published online: 3 December 2005
# Springer-Verlag 2005
Aerobic granules can be used for the treatment of industrial or municipal wastewater, but highaeration rate is required for the stable operation of the granular sludge system.
Immobilization technology has been widely applied in fields of fermentation, enzyme reaction, and wastewater treatmentbecause of its advantages of easy separation of
solid from liquid and high reaction efficiency.
Until 1997, Morgenroth et al. (1997) found that aerobic microorganisms also could be immobilized withoutcarrier and form compact granules, but the operation conditions inducing self-immobilization of aerobic microorganisms are not the same with those of anaerobic microorganisms.
Since then, manyresearches focused on this field. Although the mechanism of self-immobilization of aerobic microorganisms is not fully understood yet, operating factors
involved in aerobic granulation have been widelyinvestigated. So far, almost all aerobic granules were formed in sequencing batch reactor (SBR) with distinct feast and famine periods.
The typical feature of SBR is its cycle operation includingfilling, aeration, settling, and discharging. This kind of batch operation mode consists of feast and famine periods, which has been proved to be favorable to grow stable aerobic granules. Feast period meansthat there is external carbon source in bulk liquid, and famine period means that there is no external carbon source in bulk liquid.
Dissolved oxygen (DO) profile in one cycle of SBR showed that DOin feast period was low, while DO was close to saturation value in famine period (Beun et al. 2002; Arrojo et al. 2004). The distinct difference in terms of
external carbon concentration and DO...