Model Development and Light Effect on a Rotating Algal Biofilm

Abstract

Microalgae are generally grown in suspended cultures. These last years, alternative processes have emerged, where microalgae are attached to a moving support. Microalgae can indeed grow and attach to the surface to form a biofilm. Photosynthetic biofilm based processes demonstrated lower energy demand, higher productivity and lower water usage which stimulated a growing interest. In this paper, a rotating algal biofilm (RAB) model is considered based on the Han model describing photosynthesis dynamics and photoinhibition. The effect of light on microalgal biofilm growth and productivity is analyzed and discussed. Two key design parameters are studied: the conveyor velocity and shape, triggering the light dilution factor which strongly affects productivity. The benefit of the process is assessed when the conveyor velocity is fast enough. A numeric study is carried out to identify the optimal folding of the conveyor.