A food grade corn starch of Cargill, Turkey, was used as the flocculant. The starch solution was prepared by dispersing 1g starch in 900ml of cold (room temperature) distilled water and adding NaOH of 1M concentration to the suspension until starch molecules were fully dissolved. It was then homogenized in a high speed blender for 30s and made up to 1L for the tests.