Modelling approach to better control biofouling in fluidized bed membrane bioreactor for wastewater treatment

A mathematical model has been developed to better understand fouling mitigation mechanisms in particle-sparged membrane bioreactor. The model developed herein assumes two fouling mechanisms, (i) the pore blocking leading to the decrease in membrane surface porosity and (ii) the progressive development of compressible cake layer on the membrane surface. The model has been validated by comparison with trans-membrane pressure data registered from the bioreactor filtering a synthetic solution consisting of bentonite, sodium alginate and bovin serum albumine (BSA). Two nonporous media have been tested, Polyethylene terephthalate (PET) beads and silica particles with different dosage (0, 10, 30, 50 and 70% (v/v)). Compared to the experimental data, the model shows satisfactory fitting with R² ≥ 93%. For both media tested, an optimal dosage to minimize fouling rate was observed at 50% (v/v). Even if both fouling mechanisms have been mitigated by adding fluidized media, pore blocking was more pronounced than cake formation. Moreover, better pore blocking mitigation was observed with PET media (50% (v/v)) having bigger size and lower density than silica particles.