Emerging Technologies NSFANSI Standard 55 Evaluation of Microbiological Reduction Performance Capability Low Pressure uV Lamps 254nm Wavelength Performance Equated to Delivered Dose Class ID: 294829
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Slide1
uV Drinking Water Treatment
Emerging TechnologiesSlide2
NSF/ANSI Standard 55Evaluation of Microbiological Reduction Performance Capability
Low Pressure
uV
Lamps
254nm
Wavelength
Performance Equated to Delivered Dose
Class
A 40
mJ
/cm
2
With Sensor Technology – Unknown Water Supply
Class B 16
mJ
/cm
2
Without Sensing Technology – Known Water Supply
Test Organisms
Bacteriophage
MS2 – Class A
S.
cerevisiae
/Bacteriophage
T1
– Class BSlide3
How does UV inactivate micro-organisms?
Well Accepted Mechanism of UV Inactivation
At a wavelength of 254nm, UV will break the molecular bonds within micro-organismal DNA, producing thymine dimers and thereby destroying them or prohibiting growth and reproduction
253.7nm
UVC Absorbance of DNASlide4
Emerging TechnologiesAlternate uV
Technologies Are Under Active Development
LED
DBD
Excimer
MP CFL
HalogenuV Emissions May Be Monochromatic or Polychromatic at Wavelengths Other Than 254 nmSlide5
Market TrendsSlide6
The Issue (Opportunity)Standard 55 Performance Based Upon Dose…..Dose Equated to Anticipated Log Reduction at 254 nm Wavelength
Relationship of Dose to Log Reduction Based Upon Established Research and Scientific Findings
The Question (s)
Does the Dose/Log Reduction Relationship Hold For Alternate Technologies Emitting as Wavelength (s) Other than 254 nm?
Is There a Need for the Development of Alternative Measuring Tools?
Can These Alternate Technologies Be Built Into Standard 55?Slide7
Wavelength
(nm)
Polychromatic
Monochromatic
Organisms
Main
Findings
Ref210, 220, 230, 240, 260, 270, 280, 290
Adenovirus
More DNA damage was observed at >260nm
Loss of viral infectivity was due to the UV damage to a viral component at <240nm
S.
Beck
et al
.,
Environ.
Sci. & Technol.
,
2014
214, 230, 240, 254, 265, 280, 293Bacillus / sporesMS2 coliphageMS2 was 3 times more sensitive to near 214nm compared to the 254 nm B. subtilis spores were most sensitive to 265nmH. Mamane-Gravetz et al., Environ. Sci. & Technol., 2005216, 230, 242, 255, 263, 271, 281, 290Cryptosporidium parvum oocystsC. Parvum oocyst was most sensitive to 271nmOocyst can be appreciably inactivated at low UV dose K. Linden et al., Water Sci. & Technol., 2001222, 228, 239, 260, 280, 289AdenovirusOther wavelength emitted by the polychromatic UV lamps are more effective than the 254nm emitted by LP UV. K. Linden et al., Appl. Environ. Microbio., 2007
Summary of Previous Wavelength WorksSlide8
MotionThe motion is that the uV
Task Group be requested to evaluate the available research associated with alternate
uV
technologies related to the germicidal treatment of water and report back to the Joint Committee their findings and recommendations for accommodating these technologies within the NSF/ANSI standards framework.Slide9Slide10Slide11Slide12
How Emerging Technologies InactivateHow UV inactivates254nm comparison to other wavelengths
MS2 Surrogate potential
E
Coli
S
Typhimurium LT2Bacillus Subtilis
SporesSlide13
How does 253.7nm compare to other wavelength?
Mamane-Gravetz
et al.
,
Environ. Sci. & Technol.
,
2005
Linden
et al.
,
Water Sci. & Technol.
, 2001
Beck
et al.
,
Environ. Sci. & Technol.
, 2014
Linden
et al.
, Appl. Environ. Microbiol., 2007 Slide14
How does MS2/254nm Inactivation compare to bacteria / waterborne pathogens?
Bowker
et al.
,
Water Research.
, 2011
Ren
Zhuo
Chen
et al.
,
Water Research.
, 2009Slide15
How does MS2/254nm Inactivation compare to bacteria / waterborne pathogens?
Mamane-Gravetz
et al.
,
Envirron
. Sci. Technology.
, 2005
Ren
Zhuo
Chen
et al.
,
Water Research.
, 2009Slide16
Testing Protocol OpportunitiesRevision to NSF/ANSI Standard 55
MS2 as surrogate
Development of new NSF Certification
Alternative Surrogate