[Studies on aerobic granular sludge cultivated under selective pressure]

Area of Science:

• Environmental Microbiology
• Wastewater Treatment Engineering

Context:

• Conventional activated sludge systems face limitations in efficiency and operational stability.
• Aerobic granular sludge offers a promising alternative for enhanced wastewater treatment.
• Sequencing Batch Reactors (SBRs) provide a flexible platform for cultivating specialized microbial consortia.

Purpose:

• To investigate the formation and characteristics of aerobic granular sludge.
• To evaluate the impact of operational parameters, including sedimentation time and chemical oxygen demand (COD) loading rate, on granule development.
• To assess the performance of the developed aerobic granular sludge under high COD loading conditions.

Summary:

• Aerobic granular sludge was successfully cultivated in an SBR using glucose as a carbon source, starting from conventional activated sludge.
• Selective pressures, including reduced sedimentation time and increased COD loading rates, promoted granule formation, observed in three distinct stages.
• Mature granules (6-9 mm diameter) exhibited excellent settling velocities (32.7 m/h) and high mixed liquor suspended solids (MLSS) concentrations (7800 mg/L), demonstrating high activity and stability at elevated COD loads (4.8 kg/(m3.d)).

Impact:

• Demonstrates a viable method for producing robust aerobic granular sludge with superior settling and treatment capabilities.
• Highlights the importance of optimizing SBR operational conditions for efficient granulation and enhanced COD removal.
• Provides insights into the properties of aerobic granular sludge, paving the way for its wider application in advanced wastewater treatment.