Abstract: A process for treating an aqueous liquid. The process includes: passing the liquid by force of gravity through a treatment area, the liquid having an upper surface exposed to ambient pressure; disrupting the flow of the liquid as it passes through the treatment area, and exposing the upper surface of the liquid as the flow is disrupted to UV light. Disrupting the flow includes directing lower portions of the liquid toward the surface of the liquid to bring such portions into contact with UV light. A process for treating an aqueous liquid in which the treatment process is monitored. This process includes passing the liquid through a treatment area to bring the liquid into contact with reflective walls submerged below an upper surface of the liquid, and exposing the upper surface of the liquid to light emitted from a UV light source such that UV light penetrates the liquid to strike the submerged reflective surfaces and to be reflected therefrom to emerge through the upper surface of the liquid.

Abstract: Method and apparatus for treating a pressurized liquid. The apparatus includes pressurized liquid treatment chamber having a window transmissive to UV light; a UV light source outside of the chamber to emit UV light into the chamber; a shaft which extending between inlet and outlet ends of the chamber which turns about a central axis of the chamber; a flexible cleaning member affixed to the shaft and engaging an interior surface of the window; and at least one member extending radially from the shaft into the treatment chamber to disrupt axial flow of water through the chamber.