Insights into mechanism of aerobic granulation in sequencing batch reactor

Abstract

Aerobic granulation is a novel environmental biotechnology recently developed for treating a wide spectrum of wastewater. Although extensive research effort has been dedicated to the development of aerobic granules in sequencing batch reactor (SBR), the mechanism responsible for aerobic granulation still remained unclear. Thus, this study attempted to address a basic question of what were the potential driving forces of aerobic granulation in SBR.

Removal of nitrogen and phosphorus from reject water of municipal wastewater treatment plant

“…Discharge time: Prolonged discharge time can delay or prevent the formation of aerobic granules even though both settling time and volume exchange ratio are properly controlled. Therefore, the discharge time of effluent from the SBR is as critical as the exchange ratio (Wang, 2007).…”

“…Aerobic granulation is a gradual process from seed sludge to dense aggregates, granular sludge, and finally compact mature granule (Tay et al, 2001a). Some important factors recommended to successfully cultivate aerobic granules from activated sludge are: high organic loading rate (Liu et al, 2003a;Moy et al, 2002); high hydrodynamic shear force (Chen et al, 2008;Tay et al, 2001b); relative short settling time (Adav et al, 2009;Beau et al, 1999;Morgenroth et al, 1997;Qin et al, 2004a;; optimized hydraulic retention time (HRT) (Beau et al, 1999;Tay et al, 2002a;; Feast-Famine regime or short time starvation ; high exchange ratio (Wang et al, 2006c); short discharge time (Wang, 2007), and addition of Fe to assist the formation of granule core (Tsuneda et al, 2004). All of the above factors could also affect the cultivation of granules in reject water.…”