A Membrane-Based Biofilm Photobioreactor for Enhanced Algal Growth Rates

In this research, a novel biofilm-based photobioreactor was proposed and evaluated. The reactor incorporated gas-transferring membranes at the base of the biofilm, allowing gas transfer directly into the biofilm. We hypothesized that CO₂ supply through these membranes could prevent carbon limitation within the biofilm, prevent pH shifts and strip excess O₂, leading to higher growth rates. Both 1-D and 2-D biofilm models were developed to assess performance compared to conventional algal biofilm reactors. Experiments were also conducted comparing both types of reactors. Results suggest the proposed system would lead to higher algae growth rates, especially when high light intensity is used. This process could provide a more efficient way to grow algae for environmental and industrial purposes. It also could enable efficient capture waste CO₂ from power plants, anaerobic digesters, or other sources.