A Survey on Sludge Granulation under Aerobic Conditions

The sludge biogranulation technology، including the two aerobic and anaerobic processes، is an important development in the field of wastewater treatment. Much is know about the process and operation of the anaerobic granulation thanks to the rather large number of studies carried out. Aerobic granulation، however، has been only recently investigated and a limited number of studies have been dedicated to such aspects of the process as the organic source، hydrodynamic shear stress، cycle، settling time، reactor configuration، solid retention time، oxygen concentration، metallic concentration، and pH. This article tries to provide a brief review of these studies and the results obtained in an attempt to identify the most important study so far conducted. Using the results، a comparison will also be made between the anaerobic and aerobic granulation processes to gain a better understanding of both.