Modeling and optimization of granulation process of activated sludge in sequencing batch reactors

Area of Science:

• Environmental Engineering
• Biotechnology
• Wastewater Treatment

Background:

• Aerobic granulation is a complex but effective wastewater treatment process.
• Accurate modeling is needed to understand and optimize granulation.

Purpose of the Study:

• To develop a mathematical model for simulating aerobic granulation in sequencing batch reactors (SBRs).
• To predict granulation progression and determine optimal operating conditions.

Main Methods:

• Developed a one-dimensional mathematical model incorporating biomass growth, particle dynamics, and sedimentation.
• Applied discretization to operational time, sedimentation, size fractions, and slices.
• Verified and predicted the granulation process under four different conditions.

Main Results:

• The model accurately predicted key granulation parameters: mean radius, biomass discharge ratio, total number, and bioparticle size distribution.
• Identified optimal operating conditions for aerobic granules (density > 120 g VSS/L, radius 0.4-1.0 mm) with high settling velocity and substrate utilization.
• Proposed an optimal control strategy involving automatic adjustment of settling time.

Conclusions:

• The developed model effectively simulates aerobic granule formation in SBRs.
• The model provides valuable insights for designing and optimizing aerobic granulation processes.
• Results aid in achieving efficient wastewater treatment through enhanced bioparticle characteristics.