Use grease trap suspended solids in wastewater and water to achieve the purpose of different specific gravity separation. Grease traps constructed multi-use advection, oily wastewater into the plane through the distribution channel is rectangular grease traps, slow flow in the horizontal direction, the flow of oil floating in the water, by collecting pipe or set the pool surface skimmer push to set the inflow tubing dewatering tank. Settling down in the grease trap in heavy oil and other impurities accumulate to the bottom sludge hopper through mud tubes into the mud tube. After treatment of the waste water grease overflow is discharged into the drainage pond, the follow-up treatment to remove emulsified oils and other contaminants. Grease traps and use the same basic principles of sedimentation tank wastewater treatment, is the use of suspended solids in wastewater and water to achieve the purpose of different specific gravity separation. Grease traps constructed multi-use advection, oily wastewater into the plane through the distribution channel is rectangular grease traps, slow flow in the horizontal direction, the flow of oil floating in the water, by collecting pipe or set the pool surface skimmer push to set the inflow tubing dewatering tank. Settling down in the grease trap in heavy oil and other impurities accumulate to the bottom sludge hopper through mud tubes into the mud tube.