A fluid contactor is taught for mixing and reacting of fluids. Mixing is enhanced by providing a suitable residence time and suitable surface area contact by forming eddy flow within the fluid and thereby the formation of vortexes. Such a contactor does not require the use of mechanical mixers. The contact chamber of the present invention can enhance chemical modification by use of chemical modifiers such as ultraviolet lamps, by allowing the positioning of such modifiers adjacent the vortexes.