Simulation of Biofouling Caused by Bacillus halotolerans MCC1 on FeNP-Coated RO Membranes

Reverse osmosis (RO) desalination technology offers a promising solution for mitigating water scarcity. However, one of the major challenges faced by RO membranes is biofouling, which significantly increases the desalination costs. Traditional simulation models often overlook environmental variability and do not incorporate the effects of membrane-surface modifications. This paper develops a bacterial growth model for the prediction of seawater desalination performance, applicable to commercial RO membranes, which can be either uncoated or coated with iron nanoparticles (FeNPs or nZVI). FeNPs were selected due to their known antimicrobial properties and potential to mitigate biofilm formation. The native seawater bacterium Bacillus halotolerans MCC1 was used as a model biofouling bacterium. Growth kinetics were determined at different temperatures (from 26 to 50 °C) and pH values (from 4 to 10) to obtain growth parameters. Microbial growth on RO membranes was modeled using the Monod equation. The desalination performance was evaluated in terms of hydraulic resistance and permeate flux under clean and biofouled conditions. The model was validated using desalination data obtained at the laboratory scale. Bacteria grew faster at 42 °C and pH 10. The pH had a more significant effect than temperature on the bacterial growth rate. The FeNP-coated membranes exhibited lower resistance and maintained a higher long-term water flux than the commercial uncoated membrane. This modeling approach is useful for improving the monitoring of feed water parameters and assessing the operational conditions for minimum biofouling of RO membranes. In addition, it introduces a novel integration of environmental parameters and membrane coating effects, offering a predictive tool to support operational decisions for improved RO performance.