The invention is a process for treatment of brown grease, where the brown grease comprises water, food solids and free-oil. This process starts with the collection of the brown grease into a container. The brown grease's pH is adjusted with a chemical treatment to produce an adjusted brown grease phase. To the adjusted brown grease phase an anionic copolymer treatment mixture is added along with a cationic copolymer to form a reaction mixture. The reaction mixture reacts for a period of time, and during this time wastewater is discharged from the reaction mixture to produce resulting solids. The resulting solids are then transferred from the container for disposal or are processed further into a fuel or soil additive.