Abstract: This invention relates to a method of improving the dewatering of alumina trihydrate obtained by the Bayer process. The method comprises treating the alumina trihydrate with the product of mixing an alkaline liquor and a C.sub.8 to C.sub.20 fatty acid, fatty acid precursor such as an ester or amide, or a fatty acid blend. The product, a fatty acid salt, is an effective dewatering aid.The alumina trihydrate may be washed with a liquor including said product, or the product may be added to a Bayer liquor slurry prior to filtration of the alumina trihydrate.The invention also contemplates a watering aid consisting of the product of mixing an alkaline liquor with a C.sub.8 to C.sub.20 fatty acid or fatty acid precursor.