The method comprises the following steps: - at the end of the decantation of the liquid fatty pick up, remove the water (ec) rinsing present in the lower part of the container of settling (3), so that the grease decanted (gd) is located in the bottom of the container (3)； - remove the grease decanted (gd) at the level of the bottom by means of a pump (5)； - transfer the grease decanted into a jar centrifuge monoaxial (7)； - a centrifugation of this grease decanted (gd) in the bottle centrifuge (7)； - transfer, by means of a pump (9), the grease purified to the body (30) of a syringe of reinjection (11), single. The apparatus comprises the pipes 4, 6, 8 and 10 connect the members 3, 5, 7, 9, 11) of the above-mentioned.
