Abstract: A conveyor apparatus has a pair of inclined, parallel, adjacent upwardly facing semicylindrical troughs, an elongated helical flight rotatably disposed in each trough, and a drive mechanism for effecting rotation of the helical flights. The lower ends of the troughs are received in a tank having spaced side walls and having spaced baffle walls between the side walls which are parallel to the side walls and extend above at least a portion of the top edge of each side wall. These top edge portions of the side walls are each adjustable about an axis normal to the side wall to a substantially horizontal position and are releasably fixable in such position. Solids introduced between the baffle walls are conveyed by the rotating flights to the upper ends of the troughs, and liquid so introduced passes under said baffle walls and over the adjustable edge portions of the side walls.