Microalgal harvesting and thickening can be achieved by means of
several techniques including coagulation–flocculation and sedimentation,
flotation, centrifugation, magnetic separation and electrophoresis [3–7]. However, in the context of wastewater treatment, only low-cost
techniques capable of managing large volumes of water and biomass
can be applied, such as coagulation–flocculation followed by a solid/liquid
separation. Indeed, coagulation–flocculation and sedimentation
may lead to a solid concentration in microalgal biomass from 1 to 5%
w/w [7], which is appropriate for downstream processes such as biogas
production.