Hydrodynamic analysis of biocarrier arrangement configurations in moving bed biofilm reactors: CFD-based investigation

Abstract

Based on the importance of bio-carrier arrangement and its remarkable effect on mass transfer, aeration efficiency, and biofilm growth in MBBRs. Four numerical models were performed based on four different bio-carrier packing configurations to study their hydrodynamic characteristics. This numerical study analyzes the impact of structured arrangement (rectangular and staggered) and unstructured (loose and dense random) bio-carrier configurations on key hydraulic parameters, represented in air distribution, water velocity profile, and pressure drop within the reactor. A 2-D model was performed using ANSYS Workbench (2024), depending on the Eulerian multiphase model and k-ε turbulence modeling to represent and simulate the multi-phase interactions. The results revealed that structured bio-carrier configurations offer better flow stability and energy efficiency. At the same time, random arrangements may be beneficial for high-BOD wastewater treatment where enhanced mixing is required. These findings provide valuable insights for optimizing MBBR design, balancing aeration efficiency, pollutant removal, and operational sustainability.