Method for treating liquid by creating a liquid cyclone photon interface

A method for treating liquids includes the steps of directing liquid into a hydrocyclone to form a liquid vortex having an inner surface defining an evacuated central portion. Photon radiation is emitted into the evacuated central portion of the liquid vortex using a photon generator positioned at an upstream end of the hydrocyclone so as to separated from the liquid. The radiation may be modulated to increase the effectiveness of the treatment. Treating chemicals can also be added to the liquid to enhance the treatment effect. The photon radiation can include lightwaves or ultraviolet rays, microwave or millimeter wave radiation, or radio frequency radiation. The invention improves the treatment time per unit of volume liquid treated, as well as reducing the maintenance associated with such systems.