Abstract: A process for simultaneously converting swine, poultry and cattle wastes to useful products comprising combining said wastes with water to form a slurry, removing feathers and grit from said slurry, subjecting said slurry to anaerobic fermentation for a period of time to produce a methane-containing gas stream and a slurry containing a partially fermented solid residue, separating the methane-containing gas stream from the slurry, separating partially fermented solid residue from the slurry and drying the partially fermented solid residue to form a feed product therefrom. The quantitative ratio of cattle wastes containing cellulosic or fibrous materials to the poultry and swine wastes containing more rapidly fermentable materials is controlled to thereby control the pH of the slurry during anaerobic fermentation. At least a portion of the methane-containing gas stream produced is utilized as fuel for carrying out the drying step.

Abstract: A method of slurrying fibrous organic materials containing grit and removing grit therefrom is provided comprising the steps of particulating the fibrous organic materials, combining the particulated fibrous organic materials with a liquid to form a slurry of suspendable grit and materials contained therein, separating non-suspendable grit and materials from the slurry and then separating suspended grit contained in the slurry therefrom. A system for carrying out the method of the invention is also provided.