A flotation apparatus for separating one phase from a dispersion containing at least a first continuous phase and a second dispersed phase so as to form a first fraction being low in the second dispersed phase and a second fraction being rich in the second dispersed phase and in particular for separating oil from a dispersion containing water as continuous phase and oil as dispersed phase so as to form a fraction being rich in oil and a clear water fraction, the flotation apparatus comprising a vessel having: - an inlet for the dispersion defining an upstream end of the vessel, - an outlet for the first fraction being low in the second dispersed phase defining a downstream end of the vessel, - an outlet for the second fraction being rich in the second dispersed phase, - an outlet for gas, - at least one underflow weir (24, 24', 24", 24"', 24' v), - at least one overflow weir (26, 26', 26", 26"', 26' v), wherein the overflow weir (26, 26', 26", 26"', 26' v) is located in a distance to and displaced in the direction to the downstream end of the vessel from the underflow weir (24, 24', 24", 24"', 24' v), - at least one gas injection means comprising at least one opening for injecting gas or a dispersion of gas in liquid into the vessel, wherein the at least one opening of the at least one gas injection means is located vertically below the underflow weir (24, 24', 24", 24'", 24' v) or is located in the channel formed between the underflow weir (24, 24', 24", 24"', 24' v) and the overflow weir (26, 26', 26", 26'", 26' v), - at least one removal means for removing the second fraction being formed during the operation of the flotation apparatus on the liquid level from the liquid level and - at least one hydraulic means for hydraulically pushing the second fraction being formed during the operation of the flotation apparatus on the liquid level of the vessel into the removal means by means of a liquid stream, by means of a liquid/gas stream and/or by means of a gas stream, wherein the respective liquid stream, liquid/gas stream and/or gas stream is ejected by the hydraulic means onto the liquid level of the vessel and/or onto the second fraction being formed during the operation of the flotation apparatus on the liquid level; wherein the vertical distance between the underflow weir and the overflow weir is 30 to 80% of the height of the vessel, wherein the vertical distance between the underflow weir and the overflow weir means the distance between the lower edge of the underflow weir and the upper edge of the overflow weir. - an inlet for the dispersion defining an upstream end of the vessel, - an outlet for the first fraction being low in the second dispersed phase defining a downstream end of the vessel, - an outlet for the second fraction being rich in the second dispersed phase, - an outlet for gas, - at least one underflow weir (24, 24', 24", 24"', 24' v), - at least one overflow weir (26, 26', 26", 26"', 26' v), wherein the overflow weir (26, 26', 26", 26"', 26' v) is located in a distance to and displaced in the direction to the downstream end of the vessel from the underflow weir (24, 24', 24", 24"', 24' v), - at least one gas injection means comprising at least one opening for injecting gas or a dispersion of gas in liquid into the vessel, wherein the at least one opening of the at least one gas injection means is located vertically below the underflow weir (24, 24', 24", 24'", 24' v) or is located in the channel formed between the underflow weir (24, 24', 24", 24"', 24' v) and the overflow weir (26, 26', 26", 26'", 26' v), - at least one removal means for removing the second fraction being formed during the operation of the flotation apparatus on the liquid level from the liquid level and - at least one hydraulic means for hydraulically pushing the second fraction being formed during the operation of the flotation apparatus on the liquid level of the vessel into the removal means by means of a liquid stream, by means of a liquid/gas stream and/or by means of a gas stream, wherein the respective liquid stream, liquid/gas stream and/or gas stream is ejected by the hydraulic means onto the liquid level of the vessel and/or onto the second fraction being formed during the operation of the flotation apparatus on the liquid level;