An oxidation chamber used for irradiating an incoming liquid containing unwanted organic pollutants has a structure that facilitates automatic self-cleaning at intervals. A modular construction is used, and three basic types of modules are employed. One of the modules is a TEFLON TM lined carbon steel pipe through which a shuttling scraper is forced at intervals. The shuttling scraper includes an annular wiper that simultaneously cleans the inside surface of the surrounding tubular module as well as the outside surface of an enclosed quartz tube. The annular wiper sealingly engages the quartz tube and the tubular module so that it is driven like a piston by the full pressure of the liquid. When the shuttling scraper has reached the end of the tubular module, it parks itself in a position that causes only minimal pressure drop. This automatic self-cleaning feature of the oxidation chamber overcomes one of the most serious problems encountered with this type of equipment, namely the tendency of a slime to form on the UV lamps and on the normally reflective walls of the chamber, thereby reducing the efficiency by reducing the amount of UV radiation reaching the liquid. When this occurred in prior art apparatus, it was necessary to shutdown the operation and to dismantle the oxidation chamber to clean the lamps and chamber walls.
