Abstract: A quantity of water deposited on sand particles is adjusted to a predetermined value by utilizing a method and apparatus disclosed having a hopper through which the sand particles to be treated are supplied. A velocity energy is imparted to the particles to project them in a predetermined direction, thereby causing the particles to collide against rotating drums. As a result of the collision, a portion of a quantity of water initially deposited on the particles is removed therefrom and transferred to the drums, which is thereafter separated from the drums by a centrifugal force created by rotation of the drums. A plurality of notches or slits may be formed to axially extend along the periphery of the drums so that the deposited water moving along the periphery will tend into contact with be separated therefrom when it comes to one of the notches or slits. An air jet stream passing through the respective slits to the outside will function to facilitate the water removal from the periphery of the drums.