A grease separator is used in industrial and catering establishments from which the fats and oils of plant and animal origin can be poured into the environment. Their use is mandatory in large kitchens, hotels, hospitals, restaurants, foodstuffs, slaughterhouses, meat processing plants, etc. The grease separator complies with the SIST EN 1825-1 standard and consists of two parts, the sludge settler and the fat collector. In the sludge ditch, the waste water stream settles down, and the heavier particles settle to the bottom. In the fat reservoir, however, oils and fats with a lower density are separated from the water and retained on the surface. Purified water flows into the knee at the outflow, which is submerged below the level of fat and oil.