A liquid treatment apparatus for treatment of liquid contaminated with living organisms comprising: - a liquid treatment reservoir, - an inlet conduit to allow the liquid to be treated to enter said reservoir, - a liquid treatment device with which said reservoir is provided, and - an outlet conduit for discharging treated liquid; - wherein said liquid treatment device comprises: - a rotating means having a first surface for receiving the liquid to be treated and a rotational axis that is substantially perpendicular to the first surface, where the first surface is provided with engaging means for engaging the liquid and to provide acceleration to the liquid upon rotation of the rotating means, and where the rotating means is a substantially circular disk having a centre area and a peripheral edge defining the first surface, - a stationary means which is arranged to form an inner boundary in order to constrict the liquid on the first surface of the rotating means, where the rotating means rotate relative to the stationary means, where the stationary means comprises an annular collar that is suspended at a predefined distance above the first surface of the rotating means, and the stationary means is arranged to define an uninterrupted annular slit between the first surface of the rotating means and a first end of the stationary means allowing the liquid to pass in a radial direction away from the rotational axis between the rotating means and the stationary means and out of the liquid treatment device; - where said rotating means is positioned outside an inner volume of said stationary means; - where the engaging means are at least provided on a surface area of the rotating means that defines the slit, ensuring that upon passing through the slit in a radial direction the liquid has passed a surface area of the rotating means that is provided with the engaging means - and where, within the reservoir, gravity forces the liquid to engage the first surface of the rotating means. - a liquid treatment reservoir, - an inlet conduit to allow the liquid to be treated to enter said reservoir, - a liquid treatment device with which said reservoir is provided, and - an outlet conduit for discharging treated liquid; - wherein said liquid treatment device comprises: - a rotating means having a first surface for receiving the liquid to be treated and a rotational axis that is substantially perpendicular to the first surface, where the first surface is provided with engaging means for engaging the liquid and to provide acceleration to the liquid upon rotation of the rotating means, and where the rotating means is a substantially circular disk having a centre area and a peripheral edge defining the first surface, - a stationary means which is arranged to form an inner boundary in order to constrict the liquid on the first surface of the rotating means, where the rotating means rotate relative to the stationary means, where the stationary means comprises an annular collar that is suspended at a predefined distance above the first surface of the rotating means, and the stationary means is arranged to define an uninterrupted annular slit between the first surface of the rotating means and a first end of the stationary means allowing the liquid to pass in a radial direction away from the rotational axis between the rotating means and the stationary means and out of the liquid treatment device; - where said rotating means is positioned outside an inner volume of said stationary means; - where the engaging means are at least provided on a surface area of the rotating means that defines the slit, ensuring that upon passing through the slit in a radial direction the liquid has passed a surface area of the rotating means that is provided with the engaging means - and where, within the reservoir, gravity forces the liquid to engage the first surface of the rotating means.