How it works
They are vertical transparent columns into which air (and CO₂) is injected at the bottom. The bubbles rise, mix the culture, keep it in suspension and favour gas exchange, removing excess oxygen. They take up little floor area.
When it is used
They are widely used as inoculum reactors and in research, as well as in production when good gas transfer and efficient use of vertical space are desired. Their mechanical simplicity (no internal moving parts) eases maintenance.
Advantages
- +Good gas transfer (bubble mixing)
- +Small floor footprint (vertical)
- +Simple design, no internal moving parts
Limitations
- −Lower illuminated surface per volume
- −Scaling limited by diameter (self-shading)
- −Moderate productivity per column
FAQ
As inoculum reactors, in research and in production when good gas transfer and vertical space use are desired.
Diameter: if the column is too wide, the inner cells receive little light (self-shading).
Sources
- Richmond, A. & Hu, Q. (eds.) (2013). Handbook of Microalgal Culture: Applied Phycology and Biotechnology. Wiley-Blackwell.
- Chisti, Y. (2007). Biodiesel from microalgae. Biotechnology Advances, 25(3), 294–306.
- Spolaore, P. et al. (2006). Commercial applications of microalgae. Journal of Bioscience and Bioengineering, 101(2), 87–96.
- Mata, T.M. et al. (2010). Microalgae for biodiesel production and other applications: A review. Renewable and Sustainable Energy Reviews, 14(1), 217–232.
Scientific outreach based on specialised literature. Scientific review: pending.