An apparatus for conveying a cellulosic feedstock is disclosed. The apparatus comprises an enclosed volume having a lower surface comprising a plurality of longitudinally extending portions. Each longitudinally extending portion has an inner surface that is arcuate in transverse section. A plurality of conveyance members are provided within the enclosed volume. Each conveyance member is associated with one of the inner surfaces and configured to sweep the one of the inner surfaces. Additionally, a method for treating a cellulosic feedstock is disclosed. The method comprises providing a cellulosic feedstock being less than 100% saturated moisture. The cellulosic feedstock is introduced into a longitudinally extending enclosed volume, and conveyed longitudinally through the enclosed volume while being mixed.