A VERTICAL ALVEOLAR PANEL (VAP) FOR OUTDOOR MASS CULTIVATION OF MICROALGAE AND CYANOBACTERIA

A vertical alveolar panel (VAP) for microalgal mass cultivation has been devised and developed. VAP reactors with a surface area of 0.5-2.2 m2 were constructed from Plexiglas alveolar sheets 1.6 cm in thickness and used from May 1989 to February 1990 to grow Anabaena azollae and Spirulina platensis in the climatic conditions of Central Italy. The VAP has proven to be well suited to the outdoor mass cultivation of cyanobacteria, allowing operation at high cell concentrations (4-7 g liter-1) and achieving high biomass productivity even in winter. The high surface-to-volume ratio (80 m-1), its flexible orientation with respect to the sun's rays, effective mixing and O2 removal through air bubbling and a good control of environmental and nutritional conditions seem to be the major advantages of the system.