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UV News Note: These UV news items have been gleaned from the Internet. The UV news are partially reproduced as found. AAW takes no responsibility for their accuracy. The links to the full UV articles were active at the time of posting.

UV Articles 2013

UV News IUVA News: Ultraviolet Germicidal Irradiation in Building Air-Handling Systems: State-of-the-Art

Ultraviolet Germicidal Irradiation in Building Air-Handling Systems
Germicidal UV fixtures downstream of a cooling coil
 

The most recent issue of IUVA News, published by the International Ultraviolet Association, includes an article from Shelly L. Miller and Julia Luongo from the University of Colorado Boulder. The article, titled Ultraviolet Germicidal Irradiation in Building Air-Handling Systems: State-of-the-Art, discusses the benefits of using germicidal UV in the air conditioning systems to reduce energy consumption and realize energy savings. The authors point out that the buildings are responsible for about 40% of the total energy consumption in the USA with more than half of that going to heating, ventilating and cooling the indoor air.

One of the factors for reduced heat exchange efficiencies and reduced air flows through heating and cooling equipment is the bio-film forming on the heat exchangers. The authors cite research according to which various microorganisms growing inside the air handlers often contribute to building-related diseases in occupants in addition to increased energy consumption.

Even though regular cleaning and maintenance of the air handlers is recommended it is not usually done as often as needed and the chemical disinfectants used to reduce microbial contamination can be dangerous to the service technicians as well as the occupants of the buildings. Some harsh chemicals can also shorten the life of the AC equipment.

The authors assert that there is enough background information and regulatory requirements to justify the use of germicidal ultraviolet technology for keeping the air conditioning systems running at design capacity. This is achieved through reduced bio-fouling and also results in lower maintenance and energy costs and better indoor environment. The portion of the GSA Facilities Standards for the Public Buildings specifying the use of germicidal UV downstream of cooling coils is quoted. It is also shown that deploying germicidal UV systems for cooling coils can count toward LEED credits, specifically in the "Innovation by Design" area.

The article concludes that more experimental research is needed in real buildings as the UVGI technology is increasingly more widely used for energy and maintenance savings and improvement of the indoor environments. Germicidal UV should prove to be an excellent tool for achieving energy savings for many buildings containing heating, ventilation, air conditioning and refrigeration systems.

Complete article here: Ultraviolet Germicidal Irradiation in Building Air-Handling Systems: State-of-the-Art

UV News Water Online, Feb 19, 2014: UV Technology Offers Solution For Emerging Water Crisis
By Jon McClean

UV Systems Wastewater
Modern, closed vessel wastewater UV system with
automatic wipers and UV monitor camera.
Picture Courtesy ETS LLC

The emerging crisis of water shortage is now getting more headlines, and it is noticeable that the political debate now must include measures to cope with the pending emergency. Across the nation, from northern California to southern Florida, communities are at risk of simply running out of water. In January 2014, The California Department of Health produced a list of 17 communities that are within 100 days of running dry. The population of the U.S. has grown by 99% since 1950, and water demand has surged by 127%. So a combination of climate change and demand growth is placing unprecedented demands on potable water, and a recent report by Columbia University cites water stress in many US cities, including Cleveland, OH, Miami, FL, and several Texas cities including Houston and El Paso. Several regions now have in place plans to replace the use of potable water by reclaimed wastewater. Many are turning to UV as an effective barrier to enable the reuse of wastewater, for indirect reuse, and aquifer recharge.

UV has been used since 1917, and it is expected that UV will overtake chlorine as the predominant disinfection method for wastewater within 15 years. UV is a simple, physical and non-intrusive method of rendering organisms non -viable, and thus unable to replicate or cause further nuisance. Many microbes now demonstrate tolerance to chlorine; this should come as little surprise when one considers how mosquitoes have overcome insecticides, how weeds overcome herbicides, or indeed how microbes easily overcome antibiotics. UV light works by blowing apart the DNA, found within all living organisms. When the UV becomes damaged, the normal cell function of respiration, replication and reproduction rapidly cease. It has been noted on a number of occasions that when the microbes are exposed to sunlight, that some repair is observed. This phenomena has led to the older open channel style UV systems being covered, and indeed has promoted the use of closed vessel UV systems that keep the sunlight away and the waste streams completely away from plant operators.

Importance Of Innovation

UV system design has benefitted tremendously from the use of Computational Fluid Dynamic (CFD) models in the last decade. These models allow system manufacturers to understand fully the performance aspects of their equipment, and critically allow the regulatory community to actually understand the impact of ancillary equipment such as butterfly valves, or directional elbows have on the performance of the UV system.

As UV became a standard barrier for the drinking water community, the same rigors is now being applied to UV use for wastewater, or reclaim water.

Once the CFD model has been developed, the model is iteratively refined to improve the accuracy when compared to the actual microbial performance of the UV system. Typically the leading UV manufacturers are now able to make extremely accurate predictions. The wastewater systems are validated, usually by an expert third party such as Carollo Engineers, or HDR HydroQual. The performance envelope for the validation experiment is given much consideration as a typical NWRI (Title 22) system validation can cost well over $ 200,000 per reactor. The largest lamps currently in use in closed vessels are 800watt amalgam lamps. The older medium pressure systems that first appeared for reuse applications are too inefficient, as areas where water reuse is needed it is typically hot and air conditioner units are very popular. This makes water reuse areas not just water stressed, but also power stressed. Many water reuse communities will need to ration power in the hottest months of the year. Amalgam technology will consume approximately 1/3 of the power of a medium pressure unit, so communities who were early adopters are now able to upgrade their older UV systems and see rapid payback due to energy savings.

In the face of unprecedented climate change, and surging water demand we have no alternative other than to examine ways of conserving water. Many traditional uses of water, such as agricultural use, urban irrigation, dust control, enhanced oil recovery (hydraulic fracturing) will all switch, or have already switched from using potable water to using reclaimed water. In many inland communities, the scarcity of available water is leading to the direct reuse of water. The challenge quickly becomes one of communication and ensuring that complex, and emotive issues that pose the professional water community little issue are well explained to a non- technical customer. In reality we have no choice, but let us take the time to explain carefully how well protected we really are, and that we do have an optimistic outlook after all.

UV News IUVA October 24, 2013 - PR: International Ultraviolet Association (IUVA) Members Present Awards to UV Innovators at World Congress 2013

2013 IUVA World Congress
World Ultraviolet Congress - September 2013
 

The International Ultraviolet Association (IUVA) recently held a World Congress with the International Ozone Association in Las Vegas, NV. During the conference, the IUVA made some distinguished awards to UV scientists, engineers, industry leaders and students.

Washington, DC, October 24, 2013 - Members of the IUVA proudly presented awards to UV scientists, engineers, industry leaders and students at the World Congress 2013 in Las Vegas.

The UV Engineering Project Award winner for 2011-2012 is the Catskill-Delaware Ultraviolet Disinfection Facility. The new state-of-the-art facility is owned by the New York City Department of Environmental Protection and was designed by CDM Smith and Hazen and Sawyer, with construction management by Malcolm Pirnie/ ARCADIS and CH2M Hill. The Catskill-Delaware Ultraviolet Disinfection Facility was recognized as an exemplary field application of UV Technology.

The Green Innovations in UV Science and Engineering Award winner is a solar powered UV Water Purifier designed by Naiade, for Nedap Light Controls. The IUVA Green Innovations award recognizes an exemplary product or process improving the Green image of UV applications and is reviewed for its Green design and engineering attributes.

The UV technologies industry has grown over the past decade across the globe and is poised for even more expansion with the introduction of UV LED technology. UV LEDs are small, energy efficient devices that have revolutionized the UV industry. The UV Product Innovation award recognizes novel UV product design and engineering. It was given to UV-Pearl for a UVC LED Water Disinfection Device by Aquionics, Inc.

The UV Research Paper of the Year (2011-2012) was awarded to Olya Keen, Nancy G. Love and Karl G. Linden for, “The role of effluent nitrate in trace organic chemical oxidation during UV disinfection” published in Water Research in 2012. A Classic UV Paper Award went to Jeannie L. Darby, Kile Snider and George Tchobanoglous for “Ultraviolet Disinfection of Wastewater Reclamation and Reuse Subject to Restrictive Standards” published in Water Environment Research, 1993.

The UV Light Award for Volunteer Recognition was given to George Elliot Whitby to recognize his dedicated support of IUVA and its mission. The Lifetime Achievement Award in UV Science and Engineering was given to Dr. James R. Bolton, Professor Emeritus of University of Western Ontario and President of Bolton Photosciences Inc.

Students studying UV technology were also recognized for their contributions to research. Best UV Papers were awarded to: Jacque-Ann Grant, University of Toronto; Olya Keen, University of Colorado; Mengkai Li, Chinese Academy of Sciences.

IUVA’s mission is to advance the science, engineering and applications of ultraviolet technologies to enhance the quality of human life and to protect the environment. Founded in 1999, it is a 501(c)3 educational association of more than 500 members in 35 countries. IUVA is recognized as the leading knowledge-base and voice for UV technologies through its varied conferences and programs.

UV News July 11, 2013: International Ultraviolet Association 2013 World Congress
IUVA.org

The International Ozone Association and International Ultraviolet Association 2013 Joint World Congress and Exhibition continues a long series of successful congresses organized worldwide by the IOA and IUVA to provide an international forum for all concerned with fundamental, engineering and applied aspects oxidation techniques involving ozone and related oxidants and/or UV techniques.

It will be the third joint IOA and IUVA World Congress and Exhibition that will combine the 20th International Ozone Association World Congress and 6th International Ultraviolet Association World Congress.

The Congress Preliminary Program is now available on-line at: www.worldcongress2013.org

UV News June 6, 2013: Improved Principals of the Biological Safety Cabinet Design
Labmate-online.com/news/

Biosafety Cabinet with Germicidal Ultraviolet
Improved Biological Safety Cabinet with Germicidal UV
 

The new CellGard HD ES NU-481 Laminar Flow Class II, Type A2, Biological Safety Cabinet offers personnel, product and environmental protection for handling of hazardous particulate drugs and powders. ISO Class 5 sterility and protection for your valuable in process work materials.

True Laminar airflow provides a sterile environment that minimizes cross contamination. A strong air barrier 105fpm (0.53 m/s) protects the end user from hazardous materials in the work zone. Multiple oval HEPA pre-filters provide the primary means for particulate filtration that allows for an efficient and safe bag-in/bag-out filter change without exposing the interior HEPA filters. Environmental protection is achieved by all contaminated air passing through a 99.99% HEPA filter.

NuAire incorporates our existing technology and new DC ECM technology to give you the best value. There are many added benefits from DC ECM Technology: Less energy to operate, longer filter life, greater horsepower and lower potential RPM; integrated digital control system and the lowest possible noise and vibration.

The unique TouchLink™ Electronic Control System monitors and controls all cabinet functions: On/off functions for fluorescent and germicidal ultraviolet lights, blower motor and interior outlets. Monitors high/low limits for airflow and window position; Date/clock display; laboratory timer, set purge cycles, outlet timer, UV light timer, auto-run timer, night setback, or weekend turn-off; Complete diagnostic functions for a NSF trained service technician or certifier.

UV News June 6, 2013: Determining Power Quality and Reliability Criteria for Ultraviolet (UV) Disinfection in Drinking Water Facilities
Waterworld.com

There are many benefits in using Ultraviolet (UV) light instead of, or to augment, chlorine disinfection in many drinking water facilities. However, UV treatment presents some unique power challenges not faced by other processes in drinking water treatment. This white paper focuses on the power concerns of UV applications. Because of this power focus, including clarification of the UV Disinfection Guidance Manual, this document is primarily intended for the design of the electrical system feeding UV applications. Some material has been added throughout this white paper and its appendices for facility management and operations personnel.

UV News June 4, 2013: Moldy strawberries? Not for 9 days with UV LEDs
John Roach, NBC News

Strawberries are a treat to treasure, but if stashed in the fridge for a handful of days, they're likely to grow an undesirable goatee of mold. Those days may be numbered, according to researchers who've shown that exposing the red fruit to low levels of ultraviolet light doubles their shelf life.

The proof-of-concept results stem from a challenge given by an undisclosed refrigerator manufacturer to the maker of new light-emitting diodes (LEDs) that emit ultraviolet (UV) light at wavelengths found in sunlight transmitted through the atmosphere.

What exactly the lights are doing to the berries to stave off mold is unknown, according to Steven Britz, a researcher at the U.S. Department of Agriculture's Food Components and Health Laboratory, who led the experiments as a side project with funding from the LED maker, Sensor Electronic Technology Inc.

"We have a hypothesis that we have tested," he told NBC News. "We could be activating defense genes in the strawberry in part. That's been shown by other people in published papers."

Other possibilities include a germicidal effect on the mold spores or a modification of the cell walls on the strawberries that somehow make them less hospitable to the growth of mold.

Whatever the reason, tests in Britz's lab found that when the strawberries are stored in a fridge under the lights continuously, spoilage was delayed for at least nine days, which is more than 50 percent longer than they unexposed berries.

Analysis of the strawberries revealed slightly higher levels of the red pigment in strawberries, normal levels of sugars and acidity, he noted.

"The strawberries, from what we could deduce, looked good," Britz said.

But did the researchers eat them?

"No, we didn’t' have enough," he said, explaining that the experimental setup allowed for just four strawberries in each container, which they kept for other analytical tests. "But they looked good, and they smelled good … I wouldn't have hesitated to eat them."

Britz will present the results of the tests at the Conference on Lasers and Electro-Optics 2013 being held June 9-14 in San Jose, Calif.

UV News March 26, 2013: Crystal IS claims record performance from UV-C LEDs
ledsmagazine.com by Tm Whitaker, a Contributing Editor at LEDs Magazine

Short-wavelength UV LEDs with higher output are likely to be used increasingly in applications such as disinfecting water, sterilizing surfaces, and spectroscopy.

Crystal IS, Inc., a manufacturer of ultraviolet LEDs for monitoring, purification, and disinfection applications, has reported a UV-C LED with an optical output of 65mW at 260 nm when operated in continuous mode.
UV-C refers to ultraviolet light with wavelengths of 200-280 nm. Light in the UV-C wavelength range can be used for disinfecting water, sterilizing surfaces, destroying harmful micro-organisms in food products and in air, and for spectroscopy applications.

Leo Schowalter, founder and CTO of Cystal IS, described the latest results as “a technological milestone in the continued development of brighter, more efficient and reliable UV-C LEDs. By employing die thinning and encapsulation techniques, we were able to increase the photon extraction efficiency to over 15%,” he said.

Details were recently published in Applied Physics Express. “By fabricating our LEDs on our home-grown aluminum nitride (AlN) substrates, we continue to set the pace of what is possible for the combination of highest efficiencies and longest lifetimes in the 250-280 nm wavelength range, far surpassing diodes fabricated on sapphire,” added Schowalter.

Yole Développement estimates that the UV-C lamp market was nearly $200 million in 2012, with lamps being replaced increasingly by UV LEDs.

"Our products will address some of the most pressing health concerns of our time,” said Therese Jordan, senior VP of business development. “We are seeing demand in both water and air for the disinfection and quality-monitoring aspects of UV-C. Similarly, spectroscopic instruments are also taking advantage of the high light output available in a UV-C LED.

“Unlike UV lamps, UV-C LEDs are mercury-free, compact, rugged and robust, lending themselves to an array of designs. They hold the promise of long life and environmentally friendly end-of-life disposal.”

UV News March 19, 2013: Portland Water District installs ultraviolet micro-organism killer
therepublic.com

The Portland area's drinking is now safer.

Portland Water District officials on Monday announced that a 5.5-ton ultraviolet disinfection unit has been installed in an unused underground well at the district's Standish facility.

It is part of a $12.8 million project designed to eliminate pathogens from the public drinking water supply.

The 14-foot long unit contains 84 ultraviolet lamps and can treat 52 million gallons of water a day. The light penetrates micro-organisms and kills them. A second backup UV unit will be installed later this year.

District spokeswoman Michelle Clements tells The Portland Press Herald the impact for rate payers is expected to be "minimal."

UV News March 19, 2013: Study Shows Effectiveness of Ultraviolet Light in Hospital Infection Control
infectioncontroltoday.com

Research presented at IDWeek 2012 showed that a specific spectrum of ultraviolet light killed certain drug-resistant bacteria on the door handles, bedside tables and other surfaces of hospital rooms, suggesting a possible future weapon in the battle to reduce hospital-associated infections.

Researchers at Duke University Medical Center and the University of North Carolina Hospital System used short-wave ultraviolet radiation (UV-C) to nearly eliminate Acinetobacter, Clostridium difficile or vancomycin-resistant enterococci (VRE) in more than 50 patient rooms at the two medical facilities.

“We’re learning more and more about how much the hospital environment contributes to the spread of these organisms,” says lead researcher Deverick J. Anderson, MD, an assistant professor of medicine at Duke and co-director of the Duke Infection Control Outreach Network. Given previous findings by the University of North Carolina team that UV-C is effective at decreasing methicillin-resistant Staphylococcus aureus(MRSA) in hospital rooms, he believes that the new study lays critical groundwork.

“We have a solid foundation to show that this approach succeeds in both experimental and real-world conditions,” Anderson adds. “Now it’s time to see if we can demonstrate that it indeed decreases the rate of infections among patients.”

His group’s work is among the significant research being discussed at the inaugural IDWeek meeting, which was held Oct. 17-21 in San Diego. With the theme Advancing Science, Improving Care, IDWeek features the latest science and bench-to-bedside approaches in prevention, diagnosis, treatment, and epidemiology of infectious diseases, including HIV, across the lifespan. More than 1,500 abstracts from scientists in this country and internationally will be highlighted over the conference’s five days.

“Healthcare-associated infections are linked with significant morbidity and mortality,” says Liise-anne Pirofski, MD, an IDWeek chair for the Infectious Diseases Society of America. “Although there are multiple sources for these infections, the hospital environment itself can play an important role. The findings of this study suggest that UV light could hold promise for eliminating bacteria from hospital rooms and reducing the risk of infection with these difficult bacterial pathogens in the healthcare environment. That would be a result to benefit us all.”

UV-C, which is harmful to microorganisms, has been used for decades in food, air and water purification and to sterilize equipment in laboratory settings. This study demonstrates that its medical application may offer new strategies for reducing the estimated 1.7 million hospital-associated infections that occur annually in the United States. The cost of treating these infections, often involving increasingly antibiotic-resistant bacteria, ranges from an estimated $4.5 billion to as much as $11 billion.

In their study, the Duke and University of North Carolina researchers questioned whether UV-C could be utilized to eliminate three of the most problematic germs and improve the cleanliness of patient rooms. Given the tough economics of healthcare today, hospitals’ environmental services are under pressure to turn rooms over quickly, and many surfaces can get missed by even the most diligent crews.

The study focused on general-medical and intensive-care units of the two medical centers and identified patients with infections from the targeted bacteria. Clostridium difficile, or C. diff as it is commonly known, can trigger serious intestinal conditions. Acinetobacter can cause pneumonia and serious blood, wound and urinary tract infections. VRE most frequently infects the urinary tract, bloodstream, wounds or catheter sites. Each bacterium can survive for prolonged periods on surfaces.

After the patients were discharged, the researchers obtained multiple cultures from each of five specific locations in the hospital rooms and bathrooms – high-touch areas that included bed rails, remote controls and toilets. A special machine with eight UV bulbs mounted on a central column was then positioned strategically in each room and turned on for as long as 45 minutes to eradicate both vegetative bacteria and bacterial spores. Fifteen more cultures were taken from the same locations in every room, and the pre- and post-treatment bacteria counts were compared.

The numbers of bacterial colony-forming units (CFUs) fell precipitously. Fifty-two CFUs of Acinetobacter were seen before irradiation, but only 1 CFU afterward – down 98.1 percent. As for VRE, the proportion decrease was nearly the same – 719 CFUs before and 15 after, a 97.9 percent drop.

The culturing initially was not sensitive enough to isolate C. diff, but improved techniques allowed the researchers to do further testing and the results in the UV-C treated rooms were just as dramatic.

“We would never propose that UV light be the only form of room cleaning, but in an era of increasing antibiotic resistance, it could become an important addition to hospitals’ arsenal,” Anderson says.

UV News February 8, 2013: Karl Linden, President Elect of International Ultraviolet Association Leads Research Team That Won Gates Foundation Grant
marketwire.com / Source: International Ultraviolet Association

Dr. Karl Linden, Professor of Environmental Engineering at University of Colorado Boulder, leads a research team that was recently awarded a grant from the Bill and Melinda Gates Foundation for $780,000 for the Reinvent the Toilet Challenge (RTTC). The grant challenges scientists and engineers to design a toilet that uses little or no water, is energy and cost efficient and converts waste into a useful product. Karl Linden's team proposed a design idea that utilizes solar energy to convert waste into biochar, a product that can be used as fertilizer.

Dr. Linden is the President Elect of the International Ultraviolet Association (IUVA), a position he will assume in July of this year. Many of the scientists and engineers who are members of the IUVA design and maintain systems that use ultraviolet light to disinfect water, wastewater and air. These systems are in use across the United States and globally.

Linden will be leading a team of graduate students and collaborating with two other University of Colorado professors: Environmental Engineering Professor R. Scott Summers and Chemical and Biological Engineering Professor Al Weimer. Josh Kearns, a PhD candidate, has been using a biochar process to purify drinking water in developing countries. Kearns will provide his expertise for the RTTC project.

"This project is also very student-driven," said Dr. Linden in a press release issued by University of Colorado. "Students with classroom and field-based experiences in our Engineering for Developing Communities program have provided some excellent ideas, expertise and enthusiasm to make this project possible."

Paul Swain, President of IUVA, has been a colleague of Linden's for some time. "Once again, Karl Linden is at the forefront of critical issues impacting public health and the environment worldwide," says Swain. "The IUVA is fortunate to have a true leader in our field as our next International President," he added.

IUVA's mission is to advance the science, engineering and applications of ultraviolet water disinfection and air pollutant technologies to enhance the quality of human life and to protect the environment. Founded in 1999, it is a 501(c)3 educational association of more than 500 members in 35 countries. IUVA is recognized as the leading knowledge base and voice for UV technologies through its varied conferences and programs. Visit IUVA.org.

UV News January 15, 2013: UV Experience for Inactivating Cryptosporidium in Surface Water Plants
Wateronline.com / Authors: Keith Bircher, G. Elliott Whitby and John Platz

Regulatory Background - The disinfection of pathogenic microbes in drinking water has been successful over the last century largely due to the use of chlorination. However, research conducted in the 1970’s revealed that by-products formed during the chlorination process are potentially carcinogenic and that there is a direct correlation between the concentration of chlorination by-products and the probability of certain cancers and other health problems. Following these discoveries, drinking water regulators have struggled within the confines of technological and economic limitations to find a balance between the benefits of chlorination and its harmful side effects.

In the U.S.A., the Surface Water Treatment Rule (SWTR) of 1989 mandates inactivation levels for Giardia cysts and enteric viruses, and also sets treatment standards for Trihalomethanes (THM’s, a common disinfection by-product). The SWTR provides guidance to drinking water facilities through “CT” tables that prescribe the inactivation efficacy of various processes under varying water quality conditions. By following this guidance, most water treatment plants were able to provide an adequate degree of disinfection while not compromising their Disinfection By-Product (DBP) limits and without requiring major changes to their plants. However, continuing DBP health effect research indicated that even the DBP standards required in the SWTR of 1989 produced an unacceptable level of risk and the SWTR was amended in 1996 to lower the level of DBP’s. The new DBP standards have caused many plants to fall out of compliance, requiring either extensive plant modifications or new disinfection strategies. In addition, a major outbreak of cryptosporidiosis in Milwaukee in 1993, and other minor cryptosporidiosis and giardiasis outbreaks caused regulators to create a removal requirement for Cryptosporidium oocysts in the 1998 Interim Enhanced Surface Water Treatment Rule (IESWTR) and a further treatment requirement in the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) which was promulgated in December 2005. The LT2ESWTR includes a treatment requirement for Cryptosporidium and many surface water plants will fall out of compliance due to the very poor ability of chlorination to inactivate Cryptosporidium. A void was created for water treatment technologies that will inactivate protozoa and viruses, not create DBPs, and are economically feasible. One technology that meets all three criteria is ultraviolet (UV) disinfection.

Ultraviolet light has long been known to be effective for the inactivation of viruses and bacteria in drinking water and guidelines for the disinfection of viruses with UV light exist in the U.S. EPA Alternative Disinfectants and Oxidants Guidance Manual. However prior to 1998, UV was widely considered to be ineffective at economically feasible UV doses for encysted protozoa (like Giardia and Cryptosporidium), as it was thought that UV would have to rupture the cyst membrane wall. Since Giardia was the controlling microbe for the determination of the dose of chlorine and since the UV dose required for Giardia was believed to be completely too high to be considered, no reductions in chlorine usage could be gained by using UV. As a result, UV disinfection was not used for drinking water in North America; however it has been and continues to be used extensively in Europe for groundwater.

Breakthrough research conducted by Calgon Carbon Corporation in 1997 and 1998 proved that UV disinfection is, in fact, very effective for inactivating Cryptosporidium and Giardia at low UV doses. Subsequent to Calgon Carbon’s research, the U.S. EPA created a UV working group to report to the Federal Advisory Committee (FACA) on issues and costs related to UV disinfection, resulting in the development of the UV Disinfection Guidance Manual (UVDGM) by the U.S. EPA and the promulgation of the LT2ESWTR. Many utilities are now using or are considering UV disinfection in their plants as either an additional barrier for protozoa disinfection or to get disinfection credits for Cryptosporidium and/or Giardia and to lower chlorine doses to meet the 1998 DBP standards.

Read complete article: UV Experience for Inactivating Cryptosporidium in Surface Water Plants /PDF/
 

 

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