The present invention comprises a process and apparatus for separation of hydrocarbons from hydrocarbon-containing produced water, wherein in stage 1 the hydrocarbon-containing produced water is supplied with a gas-containing component, whereupon a gas- and hydrocarbon-containing produced water mixture is fed to an inlet tube (22, 27) in the center of a tank, whereupon the said mixture is tangentially distributed via at least one nozzle (7) and at least one baffle plate (8.1), whereupon separated hydrocarbons are conveyed to at least one outlet from the tank and cleaned water is conveyed to an outlet (12) from the tank.