Abstract: A rotatable skimming trough assembly is used for skimming a liquid layer from an upper region of a tank contained liquid. The trough assembly comprises a trough extending across a portion of a tank and a bearing for rotatably mounting each end of the trough in the tank. The trough includes a cylindrical bearing sleeve which is mounted within the bearing. The bearing includes internally of its housing a plurality of rollers on which the cylindrical bearing sleeve rests. A sealing device defines a seal cavity for the rollers within which an non-emulsifying grease or oil is provided. The bearing arrangement for the trough assembly provides for extended life with minimal chance of freeze up or seizing of the bearings for the assembly.