Abstract: A process for separating grease and solid materials from a waste material so as to produce an aqueous discharge liquid. Waste material containing grease, water and solid materials is passed into a screen tank where course solid materials are separated out of the waste material. The filtrate is accumulated and injected into a series of filters wherein each filter is finer than the previous filter. The filtrate is then agitated to produce a foamed liquid which is substantially separated into a foamed oil portion and an aqueous liquid portion. The aqueous liquid portion is separated from the foamed oil portion and discharged into a sewage system. The solids captured during the filtering process are collected and in turn dried to produce a dried material which can be ground and mixed with other products and processed into animal feed, pesticides or the like.