The sludge from the aeration tank of the activated sludge process (ASP) has solid content (By Weight) of 2%. This sludge is put in a sludge thickener where sludge volume is reduced to half. Assume that the number of solids in the supernatant from the thickener is negligible. The specific gravity of sludge solid is 2.2 and the density of water is 1000 kg/m³. Calculate the solid content of the thickened sludge.