Presentation on theme: "uV Drinking Water Treatment"— Presentation transcript:
1uV Drinking Water Treatment Emerging Technologies
2NSF/ANSI Standard 55Evaluation of Microbiological Reduction Performance CapabilityLow Pressure uV Lamps254nm WavelengthPerformance Equated to Delivered DoseClass A 40 mJ/cm2 With Sensor Technology – Unknown Water SupplyClass B 16 mJ/cm2 Without Sensing Technology – Known Water SupplyTest OrganismsBacteriophage MS2 – Class AS. cerevisiae/Bacteriophage T1 – Class B
3How does UV inactivate micro-organisms? Well Accepted Mechanism of UV Inactivation253.7nmUVC Absorbance of DNAAt 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
4Emerging Technologies Alternate uV Technologies Are Under Active DevelopmentLEDDBDExcimerMP CFLHalogenuV Emissions May Be Monochromatic or Polychromatic at Wavelengths Other Than 254 nm
6The Issue (Opportunity) Standard 55 Performance Based Upon Dose…..Dose Equated to Anticipated Log Reduction at 254 nm WavelengthRelationship of Dose to Log Reduction Based Upon Established Research and Scientific FindingsThe 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?
7Summary of Previous Wavelength Works (nm)PolychromaticMonochromaticOrganismsMain FindingsRef210, 220, 230, 240, 260, 270, 280, 290AdenovirusMore DNA damage was observed at >260nmLoss of viral infectivity was due to the UV damage to a viral component at <240nmS. Beck et al., Environ. Sci. & Technol., 2014214, 230, 240, 254, 265, 280, 293Bacillus / sporesMS2 coliphageMS2 was 3 times more sensitive to near 214nm compared to the 254 nmB. 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 doseK. Linden et al., Water Sci. & Technol., 2001222, 228, 239, 260, 280, 289Other 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
8MotionThe 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.
12How Emerging Technologies Inactivate How UV inactivates254nm comparison to other wavelengthsMS2 Surrogate potentialE ColiS Typhimurium LT2Bacillus Subtilis Spores
13How does 253.7nm compare to other wavelength? Mamane-Gravetz et al., Environ. Sci. & Technol., 2005Linden et al., Water Sci. & Technol., 2001Beck et al., Environ. Sci. & Technol., 2014Linden et al., Appl. Environ. Microbiol., 2007
14How does MS2/254nm Inactivation compare to bacteria / waterborne pathogens? Bowker et al., Water Research., 2011Ren Zhuo Chen et al., Water Research., 2009
15How does MS2/254nm Inactivation compare to bacteria / waterborne pathogens? Ren Zhuo Chen et al., Water Research., 2009Mamane-Gravetz et al., Envirron. Sci. Technology., 2005
16Testing Protocol Opportunities Revision to NSF/ANSI Standard 55MS2 as surrogateDevelopment of new NSF CertificationAlternative Surrogate