ABSTRACT
This chapter provides two potential candidate parameters that may act as selection pressures in aerobic granulation in sequencing batch reactor (SBR), namely SBR volume exchange ratio and discharge time. In the field of biological wastewater treatment, sludge volume index (SVI) has been used commonly as a good indicator of microbial sludge settleability. It can be seen that the sludge SVI was inversely correlated to the volume exchange ratio, that is, a sludge with excellent settleability would be developed at a high volume exchange ratio. The improved settleability of bioparticles can effectively prevent them from being washed out of the SBR at a high volume exchange ratio. The chapter also provides experimental evidence showing that the volume exchange ratio and discharge time of the SBR are two decisive parameters that highly influence aerobic granulation, and can serve as effective selection pressures for aerobic granulation in an SBR.
