Flow regime mechanisms in sequencing batch reactor (SBR) configurations on aerobic granular sludge formation using particle image velocimetry (PIV)

Indah Water Konsortium (IWK) consistently encounters challenges in managing over 7000 sewage treatment plants (STPs) due to inadequate infrastructure for centralized treatment. In addressing the challenge of land acquisition during STP upgrades, aerobic granular sludge (AGS) technology is worth exploring. The AGS systems are designed in sequencing batch reactors (SBRs) as a superior alternative to reduce land requirements. Research trends on AGS formation by flow regime mechanism are not yet fully comprehended for different SBR configurations (column and rectangular-type) as sufficient adjusted aeration rates in producing high-quality effluent. In this study, mature AGS of about 2736 μm was achieved at 57 days of formation in rectangular-type SBR by laminar flow with an aeration rate of 4 L/min. Due to transitional flow dynamics, there was a delay of about 54 % of mature AGS (2505 μm) on day 88 in column-type SBR at an aeration rate of 6 L/min. Microbial growth indicated that effective mixing was essential in wastewater treatment to ensure uniform distribution of oxygen, nutrients, and microorganisms, while excessive agitation must be avoided to maintain granular integrity. Thus, this research offers insights into the novelty of AGS for full-scale application.