An ideal horizontal flow setting basin in 3m deep having surface area 900 m². Water flows at the rate of 8000 m³ /d, at water temperature 20°C (m = 10³ kg/m.s and p = 1000 kg/m³). Assuming Stokes law to be valid, the proportion (percentage) of spherical sand particles (0.01 mm in diameter with specific gravity 2.65), that will be removed is