The very perspective approach to microalgae recovery is by
using industrial coagulants and flocculants, agents that are used
for fresh water (Harith et al., 2009) or wastewater treatment
(Jiang, 2015). These agents have different uses according to their
roles. Thus, the coagulant must destabilize the colloidal system
by neutralizing the forces of different origin that keep it stable.
The flocculant’s role is to increase the size of flocs produced by
coagulation and agglomerate the suspended particles for their
removal (López-Maldonado et al., 2014). Currently, efforts are
under way to speed up this process. One candidate decision is to
add suitable small-particle-size sand as a ballast agent. Sand particles
would serve as seed grains when flocculation proceeds, while
accelerating the sedimentation due to their weight (Jiménez et al.,
1999). Using the recoverable ballastic agent can make the coagulation
and sedimentation proceed faster. Clearly, the use of sand as
ballastic agent in microalgae case would only complicate subsequent
stages of their processing. In view of this, the ballast sedimentation
method for microalgal biomass recovery calls for
development of a new ballast agent, which have not been so far
explored in microalgae application.