Exploring the Impact of Hydraulic Shear Force on Biosolids Granulation with CFD Simulation

Abstract Submission: Algal-bacterial consortia are emerging as one of the most promising technologies for nutrient management in wastewater treatment. However, the large-scale application of algae-based systems has been hindered by challenges in biomass harvesting, primarily due to algae's poor settling ability. Algal granulation offers a practical solution by enhancing settling efficiency, improving nutrient removal rates, and reducing biomass waste. Several factors, including hydraulic selection pressure, substrate concentration, pH, shear force, light intensity, particle uniformity, and microbial community composition, influence the granulation process. This study investigates the impact of air flow rates on the formation of algal-bacterial granules in domestic wastewater treatment, showing that aeration alters microbial community composition. Computational Fluid Dynamics (CFD) simulations demonstrated that mechanical mixing predominantly generates shear force, and increasing air flow from 0.2 to 0.5 LPM resulted in only a 12% rise in the volume-averaged strain rate, suggesting limited benefits from higher flow rates. The findings highlight the importance of optimizing aeration to improve algal-bacterial system performance while minimizing energy consumption.

Learning Objectives/Expected Outcome (Optional) :