Different types of bubbly flows in a confined channel with the aim of limiting microalgae biofilm development – Part II: Study of the development and removal of microalgae biofilm

This study aims at investigating the role of bubbles passage to prevent biofouling in thin-gap bubble column photobioreactors (PBRs) where biomass concentration is important and reactor thickness low. Different types gas sparging are tested a square channel with cross-section 4x4 mm2 mimicking PBR. Firstly, it shown that very difficult detach biofilm once has adhered wall: only bubbling conditions high wall shear rate fluctuations able part superficial layers biofilm, but no effect observed on detachment conditioning layer. Secondly, generating either fluctuations, or mean stress assess their ability delay development: both accentuate adhesion, showing may be compacted by highly confined bubbles. Thus, small whose diameter (1.4 mm) smaller than side investigated, allowing oscillations 3D hydrodynamics around bubble. bubbling, which creates most adapted limit development