Abstract: It is often desirable to operate ultraviolet (UV) water treatment systems at high fluid velocities; such as, when low UV doses are required, the UV transmittance of the water being treated is high, or when a high intensity radiation source is used. The operation of an open channel UV fluid treatment system at high fluid velocity causes a disproportionate amount of water to pass through the relatively low intensity region above the top lamp. This results in non-uniform UV dose delivery and poor reactor performance. In one embodiment of the invention, by elevating the inlet to the irradiation zone of the fluid treatment system with respect to the outlet, the amount of water that passes above the top lamp can be minimized, improving overall system performance. The means of elevation can consist of a step or slope in the channel, or a combination of both. Depending on the magnitude of elevation, an increase in maximum velocity of approximately two times can be obtained.

Abstract: An ultraviolet radiation lamp comprising a heat absorbing element on the exterior thereof such that, during operation of the lamp, the temperature of the lamp in contact with the heat absorbing element is at a lower temperature than the remainder of the lamp. The use of the lamp in a radiation source module and a fluid treatment system is also described. The ultraviolet radiation lamp is particularly useful for treatment of fluids such ambient air (e.g., containing pollutants), warm liquids and the like.