A separator is indicated, which is arranged in a container having a circular or ellipsoidal cross section and having a container wall, for separating a light liquid-water mixture, for example oil-polluted water, comprising: a feed arranged on a first side of the container having a feed chicane, which directs the supplied mixture downward and divides it into two first flow parts that are substantially of equal size, an outlet having an outlet tube, a circular or ellipsoidal flow wall having an internal wall side and an external wall side, wherein the flow wall passes through at least half of a full circle, preferably at least three quarters of a full circle, and has an opening, which is facing a second side of the container opposite the feed, wherein the flow wall between the external wall side of the flow wall and the container wall forms two flow channels at two opposite sides of the container wall in each case from the feed to the second side of the container, wherein in the flow channels in each case one of the two first flow parts is conducted from the feed to the second side of the container along the container wall, wherein the two first flow parts at the second side of the container having substantially opposite directions of flow meet one another and are reunited, and hole elements arranged in the two flow channels through which the two first flow parts flow.