A hydrocyclone is constructed of a cylindrical section joined to a conical section. Feed is injected tangentially at high speed into the upper cylindrical section, which develops a strong swiveling fluid motion. Fluid containing fine particles is discharged through overflow pipe, while the remaining suspension containing course particles discharges though the underflow orifice at the cone tip. Application of hydrocyclone for algae harvesting was studied by Mohn (1980). It was reported that only Coelastrum algae that grow in large aggregates are harvested by this method. The solid concentration of harvested algae slurry was low, with incomplete solid-liquid separation.