This sludge de-watering unit utilizes a screwpress technique wherein the free water drains through a cylindrical wire basket while the solids inside the basket are conveyed gently upward through the inclined basket by a slowly rotating screw. Within the screw press, continuous dewatering of the sludge takes place, with an increasing amount of pressure. This is due to the conical basket which ultimately reduces the volume of sludge in the press zone. To adjust the filtration pressure inside the machine, it is only necessary to discharge some sludge. An automatic washing system is set in place to take care of the screen baskets.