Abstract: An apparatus is disclosed for the photocatalytic treatment of a fluid, including inlet means for supplying fluid to the apparatus; exposing means for exposing the fluid to ultraviolet light; and outlet means for discharging the fluid from the apparatus connected to the exposing means. The exposing means include at least one channel defining a fluid flow path connected to the inlet means, wherein the channel is composed at least in part of an ultraviolet-transmitting, chemically inert material, is self-supporting and is capable of being pressurized.