Lamp Technology

Either Amalgam lamps or Medium Pressure lamps are generally incorporated into ETS systems. Amalgam lamps offer unparalleled electrical efficiency, and long and predictable lamp life (generally 12,000 hours). A correctly run Amalgam lamp is 38-42% efficient; so a 320 watt lamp is capable of delivering 134 watts of UV at 254 nm. These lamps produce a monochromatic output at 254 nm in the germicidal region. Note: amalgam technology is not recommended for use in Aquatic environments because the single wavelength emitted is not optimal for the removal of combined chlorine species. Medium Pressure technology, with polychromatic lamps emitting multiple wavelengths is usually incorporated into these applications.

UVC Lamps

Medium pressure lamps are most efficient when run at maximum power, which will reduce lamp life (8,000 hours). Typically a medium pressure lamp will deliver 12-15% efficienc, with most of the output emitted as heat (which can cause fouling of the quartz surfaces under low or no flow conditions) and long wave UV light (which encourages algae growth if not properly wiped). So a 5000 watt lamp will deliver 600 watts of germicidal UV light. The same amount of germicidal light is delivered using 72% less energy when comparing Amalgam technology. The output of these lamps is polychromatic, and they emit the wavelengths used to effectively remove chlorine from process wate and to dechloraminate pool water.

For a number of applications, medium pressure lamps are incorporated due to their small footprint and short arc length. These include retrofits into existing small footprint facilities and in marine applications where space is limited. Generally the poor electrical efficiency and shorter lamp life of medium pressure technology means a life cycle cost comparison favors Amalgam technology, however Medium Pressure lamps better suit small footprint or mulit wavelength applications such as pools and AOP processes. Several low pressure lamp manufacturers now conform with the Federal EPA's TCLP test for low mercury, and so can be properly characterized as non hazardous waste.

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