Generalities
13
Table 4:Harvesting technique of microalgae biomasse (Kim 2007 in Chisti, 2016).
1.1.9. Microalgae applications
Microalgae have a wide variety of applications in different fields (Figure 7). They can
be used in food and feed, cosmetics, biofuels, wastewater treatment, agriculture and
pharmaceuticals production. Microalgae are a source of nutrients, bioactive compounds and
renewable biomass, making them a sustainable and environmentally friendly alternative.
Technique
Principle
Advantages
Disadvantage
Centrifugation -Using centripetal force, a separation
between the culture medium and the
microalgae can be obtained thanks to
the disparity of density.
-Rapid and efficient with
95% removal efficiency.
-High energy and maintenance
cost.
Sedimentation
-Subjected to gravity, the cells in the
medium cause sedimentation.
-Low cost and energy
efficient as microalgal
biomass are left to
settle naturally.
-Takes long time to settle.
-Ineffective for small sized
microalgae.
Filtration
-pass the suspension through a filter
designed to retain cells while allowing
other substances to pass through.
-Effective recovery
for small sized
microalgae.
-High cost, algal species specific
. -Clogging/fouling of filters.
Flocculation
-Particles in solution unite to create
clusters or "flocs".
-Cost effective.
-Biomass unsuitable for further
use (animal feed or anaerobic
digestion).
-Chemical flocculant
contamination.
Flotation
-A gravity-based process in which gas
bubbles are attached to micro-algae
cells so that they can float to the
surface.
-Able to process large
volumes of biomass as
air bubbles adhere to
microalgae, making
them buoyant.
-Contamination with flocculation
agent.