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
IUVA News: 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:
Online, Feb 19, 2014:
UV Technology Offers Solution For Emerging Water Crisis
By Jon McClean
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.
2013 - PR: International Ultraviolet Association (IUVA) Members Present
Awards to UV Innovators at World Congress 2013
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
International Ultraviolet Association 2013 World Congress
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:
Improved Principals of the Biological Safety Cabinet Design
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.
Determining Power Quality and Reliability Criteria for Ultraviolet (UV)
Disinfection in Drinking Water Facilities
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.
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
"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
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.
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