Wedeco Spektron 2000e and 4000e ultraviolet disinfection systems from Xylem, designed for industrial and municipal drinking water sites with flow rates higher than 13 mgd (2,000 meters cubed per hour), provide inactivation of 4-log (99.99 percent) for chlorine-resistant pathogens, including Cryptosporidium and Giardia.

“The monochromatic lamps emit UV light at a wavelength of 254 nanometers, which is highly effective for the inactivation of pathogens,” says Tanja Burgschwaiger, Wedeco UV systems product manager for Xylem. “Used in combination with the variable-power option, the lamps provide energy efficiency under all operating conditions. In dimmed mode, they realize an average savings of 20 percent and use up to 80 percent less mercury than the previous lamp generation. With respect to sustainability, the UV lamp’s associated power savings translate to an atmospheric reduction of up to 1,100 pounds of carbon dioxide over its life cycle.”

The new models expand the Wedeco Spektron UV series to 14 systems and increase the maximum flow capacity per system to 26 mgd. The disinfection systems feature low-pressure, high-power 600 watt amalgam Ecoray UV lamp technology, reducing lamp count by about 60 percent, minimizing maintenance and lowering energy costs.

“In the past, for flow rates greater than 1,000 cubic meters per hour [6 mgd], mainly medium-pressure systems were used because lamp count for the alternate low-pressure systems was quite high,” she says. “Wedeco Spektron offers a low lamp count yet all the benefits of a low-pressure, high-power system such as energy efficiency, longer lamp life. The Wedeco series suits any drinking water treatment plant, regardless of local pipe conditions, energy costs or local legal requirements.”

Closed-vessel reactors contain UV lamps separated from the water by a UV-transmitting quartz sleeve. Cleaning mechanisms keep lamp sleeves free of fouling. UV sensor flowmeters, and in some cases ultraviolet transmittance analyzers, monitor dose delivery by the reactor.

“UV reactors used in water disinfection are designed to deliver a certain UV dose to pathogenic microbes in water to inactivate them,” Burgschwaiger says. “Lamp placement, inlet and outlet conditions, baffles and mixers all affect mixing within a reactor. Inlet and outlet conditions in particular can have a significant impact on dose delivery. The OptiCone flow diverter ensures even flow distribution with low headloss regardless of the upfront piping configuration.”

Multiple flange and mounting options enable the disinfection systems to be incorporated into existing drinking water treatment facilities when replacing inefficient or aging UV equipment.

The disinfection systems are certified by German DVGW[1] directives as well as the U.S. EPA’s UV Disinfection Guidance Manual (UVDGM 2006). 855/995-4261; www.xylem.com/treatment.