An interesting paper published on dewatering of microalgal cultures.

You can read it online at the url provided below.

A large amount of studies has been completed on the harvesting and recovery techniques of microalgal cells in dilute suspensions. Due to the differences in the biology of microalgal species, it is difficult to name one method as superior.

The choice of which harvesting technique to use depends on the species of microalgae and the final product desired. Desired microalgal properties that simplify harvesting are large cell size, high specific gravity compared to the medium, and reliable autoflocculation. In addition to these, the optimum harvesting method chosen for a particular microalgal species should have minimum energy requirements and should be as economical as possible.

The main harvesting techniques are summarized in Table 2. Centrifugation is seen as the most efficient recovery technique, yet the energy and capital costs associated are unappealing. Flocculation is also a very efficient technique that is currently applied in industries. Freshwater microalgae flocculation has been immensely studied throughout the years.

However, there is a dearth of information and comparative studies for marine microalgae. With growing concern about freshwater resources in many parts of the world, further research on the processing of marine microalgae would be very beneficial  

more http://jrse.aip.org/resource/1/jrsebh/v2/i1/p012701_s1?view=fulltext