Microwave UV: A New Wave of Tertiary Disinfection

Currently UV disinfection technologies available for use in drinking water and water reuse applications typically utilize one of three types of mercury UV lamps. These three types of mercury UV lamps include low pressure, low-pressure high-output, and medium-pressure lamps. All of these lamps contain electrodes that facilitate in the generation of UV radiation. These electrodes are of delicate construction and their deterioration is the primary source of failure in UV disinfection systems. An emerging UV disinfection technology that eliminates the need for electrodes is the microwave powered electrodeless mercury UV lamp. The objectives of this study were to review available literature on commercially available UV disinfection technologies used in drinking water and water reuse applications, and to provide a detailed explanation of the lamp properties and characteristics for comparison with the microwave powered electrodeless UV lamp. A description of traditional mercury UV lamps, the technology and application of microwave powered electrodeless mercury UV lamps, the advantages and disadvantages of the use of the microwave powered electrodeless mercury UV lamps, and a commercially available Microwave UV system that is currently undergoing validation testing as per the NWRI/AwwaRF 2003 Ultraviolet Disinfection Guidelines will be presented in this paper.