Abstract: A method and apparatus are disclosed for increasing the concentratin of suspended particles within a slurry by removal of the fluid. The slurry is passed along the surface of a porous material such as porous plastic pipe having pores of a diameter greater than that of the suspended particles. The slurry flows at a velocity parallel to the surface of the porous plastic pipe that is much greater than the lateral velocity of the fluid through the pores in the pipe. The suspended solids with diameters smaller than the diameter of the pore opening are retained and concentrated within the flowing slurry because of the high flow velocity tangential to the pores.