The document summarizes various techniques for harvesting microalgae biomass, including centrifugation, flocculation, auto-flocculation, chemical flocculation, electrical-based processes, gravity sedimentation, and flotation. Centrifugation uses centrifugal force to separate microalgal cells from suspension based on density. Flocculation involves aggregating dispersed microalgal cells into larger particles using chemicals or other means. Auto-flocculation is spontaneous aggregation without chemicals. Chemical flocculation uses salts like aluminum sulfate. Electrical-based processes use electrolysis. Gravity sedimentation relies on natural settling. Flotation takes advantage of microalgae's low density to float to the surface.