Collected reprints: Abstract 3692

Collected reprints

Abstract

Persoone, G.; Morales, J.; Verlet, H.; De Pauw, N. (1980). Air-lift pumps and the effect of mixing on algal growth. Algae Biomass : 505-522

Since turbulence is an important factor for the growth of microscopic algae, the effect of mixing intensity and mixing time, has been assessed by means of air-lift pumps as an alternative technology for the agitation of algal cultures. Batch culture experiments in enriched sea water were carried out indoors with Chlorella in 100 liter tanks and outdoors with natural phytoplankton populations in 70 m³ tanks. The respective culturing depths in these tanks were 25 and 180 cm. The role of the mixing was also evaluated against that of the pH regulation of the cultures. Mixing with air-lift pumps increased the algal growth rate significantly in comparison to non-agitated cultures. The yields were also much higher (up to 30%) in mixed than in non-mixed cultures. Another beneficial effect of air-lift mixing in algal cultures is the pH-stabilization of the medium by the carbon dioxide present in the air bubble in the pipes. With regard to mixing intensity and mixing time it is emphasized that for each type of culturing tank the most economical aeration regime must be found for which the algal output is maximal.


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