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MAHWAH, N.J. -- Scientists report in the June 2003 edition of the Journal AWWA of the American Water Works Association that tests conducted on a new U.S. water disinfection technology have observed the delivery of extremely high germicidal doses of ultraviolet (UV) light that suggest the ability to defeat a contamination of water supplies by known and listed biological pathogens, including the anthrax spore.
In the report titled, "Pulsed UV Unit May Inactivate Biological Agents," Dr. Egon Weber and Karl Scheible from HydroQual, Inc. report the results of their September 2002 tests conducted on a new water disinfection machine developed by LightStream Technologies of Reston, Virginia, USA. HydroQual is one of the leading scientific research firms on UV technologies and is frequently utilized by the U.S. Environmental Protection Agency (USEPA) for expert guidance on UV technologies, testing and procedures.
The LightStream machine tested by the HydroQual scientists utilizes a mechanism for delivery of UV light, known as "pulsed UV," that produces short pulses of UV light of extremely high intensities -- up to 6 million watts each pulse that can be repeated up to 30 times per second -- as water flows through the machine. The machine was developed to disinfect up to one million gallons per day of ordinary water and wastewater and was adapted for these tests to simulate flows of approximately 100,000 gallons per day associated with buildings, facilities or small community water systems.
Ultraviolet light, in wavelengths very similar to that of sunlight and delivered in sufficient amounts, or "doses", breaks the DNA of bacteria, viruses and other pathogens. This damage to the DNA renders the dangerous pathogens harmless. To quantify the "dose" delivered by the LightStream machine, the scientists conducted testing known as "biodosimetry" or "bioassay" challenge tests that utilize a substitute organism to measure the amount of inactivation achieved by the disinfection technology. Such procedures are used for UV reactor validation testing, and are very often required by regulatory agencies. From this data, scientists can estimate the germicidal dose delivered by a source of UV light.
According to the scientists' report, the very high doses delivered by the LightStream machine were "at the upper limit of current ability to measure UV using a common substitute indicator organism." Such high doses, the scientists reported, were "in the range required for approximately 5-6 log reductions (99.9999 percent) of the anthrax spore (Bacillus anthracis), the more resistant of the known, listed and pathogenic bacteria and viruses," and that, "Greater log reductions would be expected for other, more sensitive, listed and known pathogenic bacteria and viruses."
HydroQual, Inc., an ENR Environmental 200 firm, is an environmental engineering and consulting firm established in 1980. The firm provides a wide range of integrated engineering and consulting services to public and industrial clients around the world. The firm has had the opportunity over its history to serve many municipalities, states, governmental agencies and private corporations in the analysis of cost-effective environmental solutions to a broad array of environmental problems.
Headquartered in Reston, Va., LightStream Technologies, Inc. provides advanced technologies for the disinfection of water and wastewater. LightStream's patented technology delivers chemical- and mercury-free disinfection utilizing advanced ultra high intensity pulsed ultraviolet (UV) light and sets a new No Compromise standard in water disinfection.
Source: LightStream Technologies, Inc.