A wastewater separation system for separating an aqueous phase from an organic phase comprising oil, fat and/or grease in wastewater is disclosed. The wastewater may be collected from restaurant grease traps, as well as other food preparation facilities, schools, hospitals, processing plants and the like. A separator, such as a centrifugal separation device, comprises a wastewater inlet, an organic phase outlet for discharging low density liquid and solids and an aqueous phase outlet for discharging water and possibly other high density liquids and solids. The system can be portable and can be mounted on a vehicle for collection and treatment at various sites. Heat can be introduced to the system to accelerate the separation of the aqueous phase from the organic phase of the wastewater.