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UV Articles 2013
2013: Ultraviolet Germicidal Irradiation in Building Air-Handling Systems: State-of-the-Art
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
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:
IS claims record performance from UV-C LEDs
ledsmagazine.com by Tm Whitaker, a Contributing Editor at LEDs
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.”
Portland Water District installs ultraviolet micro-organism killer
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."
Study Shows Effectiveness of Ultraviolet Light in Hospital Infection Control
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
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
“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
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.
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
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