UV Disinfection Credit Based on Validated Algorithm

Transcription

1 211 Water Quality Technology Conference and Exposition November 13-17, 211, Phoenix, Arizona Impact of Low Wavelength UV Light on UV Dose Monitoring with Medium Pressure UV Systems Harold Wright, Mark Heath, and Jeff Bandy Carollo Engineers, West Explorer, Suite 2, Boise, Idaho, USA Christian Bokermann and Ronnie Bemus ITT-WEDECO, Boschstrasse 4, 3213 Herford, Germany UV Disinfection Credit Based on Validated Algorithm RED 1 A UVA B S S C Q D Banks E UV Dose UV Absorbance UV Lamp Output Flowrate Bank of Lamps A, B, C, D, and E constants defined by UV validation 1

2 UVDGM: MS2 Phage and Crypto Have Similar Wavelength Response 23 Draft UVDGM Provides Rationale Lamp Output (W/cm) UVDGM MP Lamp MS2 Action Crypto Action Wavelength h( (nm) Action Spectra P G 32 P 2nm G P g MS 2 Ratio P g Crypto 2

3 UVDGM: Apply Action Spectra Correction Factor is Ratio 1.6 UVDGM Ratio considers impact of: Validation microbe and pathogen wavelength response Lamp output UVDGM Ratio does not consider impact of: Quartz sleeve type Water UV absorbance Reactor configuration and UV dose distribution MP UV Lamps Emit Low Wavelength UV Light La amp Output (W/cm) UVDGM MP Lamp Modern MP Lamp

4 Synthetic Quartz Sleeves Maximize Low Wavelength UV Quartz Sleeve UVT (%) Type 214 Quartz Type 219 Quartz Synthetic Quartz Big Differences with MS2 and Crypto at Low Wavelengths Action MS 2 Crypto So MS2 REDs can overstate Crypto 4

5 and MS2 and Adenovirus at Low Wavelengths Action MS 2 Adeno So MS2 REDs can understate Adenovirus UV Sensor Systems Do Not Monitor Below 24 nm Lamp Output (W/cm) MP Lamp Output UV Sensor Response Online UVT monitors only measure at 254 nm 5

6 Lamp Aging/Fouling Impacts Lower Wavelengths More f Spectral Irradiance Aged:New Ratio of Wavelength [nm] L1 L2 L3 L4 L5 UV sensors will not capture this affect Water Absorbance Spectra Can Change Over Time.2 Water 1 Water 2 Water UVA (cm 1 ) UV254 does not capture this affect 6

7 How Big is the Issue? Data from validation study used to show impact with MS2, T1UV and T7 phage CFD-based UV dose models used to quantify differences between Crypto and validation microbes Validation of the ITT-WEDECO Quadron Reactor Validated Fall 21 at Portland Test Facility 5 MP Lamps ONORM UV sensors Three test microbes MS2, T1UV and T7 7

8 Quadron Validated with Three Sleeve Types Type 214 Quartz Type 219 Quartz Synthetic Quartz Quartz Sleeve UVT (%) Quadron Validated Using Different Water UVA Spectra UVA (cm 1) Aquifer 1 No Absorber Aquifer 2 No Absorber Aquifer 1 With Absorber Aquifer 2 With Absorber

9 REDs Impacted by Sleeve Type and Water UVA Spectra RED Ratios 214:219 RED Ratios Synthetic:219 SGA Aquifer 1.18 to to 1.6 BLA Aquifer 1.2 to to 1.18 Sleeve type and water UVA spectra can have a significant impact on validation Impacts on UV system sizing and selection can be significant CFD-Based UV Dose Models Developed for 3 MP Reactors Reactor 1-5 MP Lamps Reactor 2-1 MP Lamps Reactor 3-3 MP Lamps Hydraulics modeled using Fluent software UV Intensity and dose distributions modeled using UVXPT software Calibrated only by UV sensor readings 9

10 Good Agreement Between CFD and Validation Meausred RED (mj/cm m 2 ) BLA 214 SGA y = 1.174x R² =.9941 y = 1.747x R² = Predicted RED (mj/cm 2 ) Reactor 1 ) Meausred RED (mj/cm 2 ) 219 BLA 219 SGA y = x R² =.9826 y = x R² = Predicted RED (mj/cm 2 ) Meausred RED (mj/cm 2 ) ) Synth BLA Synth SGA y = x R² =.9968 y = 1.931x R² = Predicted RED (mj/cm 2 ) Good Agreement Between CFD and Validation Validation Fitted RE ED 12 1 y = 1.797x 8 R 2 = % 6 93% 4 85% 79% (mj/cm 2 ) UVXPT Predicted RED RED (mj/cm 2 ) 2 ) Validated RED (mj/cm m 2 ) 8 UVT 7 (%) y =.9189x 88 2 R 2 = UVXPT RED (mj/cm 2 ) Reactor 2 Reactor 3 CFD Models Must Be Proven by Comparison to Validation Data 1

11 RED Ratios Based on MS2 and Crypto Action Spectra Sleeve Water Reactor 1 Ratios Reactor 2 Ratios Reactor 3 Ratios 219 SGA Aquifer + SH TBD 219 BLA Aquifer + SH TBD 214 SGA Aquifer + SH BLA Aquifer + SH Synth. SGA Aquifer + SH Synth. BLA Aquifer + SH NY + LSA TBD Synth. NY + LSA TBD TBD Comparison of UVDGM ASCF to CFD-Based ASCF Sleeve Water Reactor 1 Ratios UVDGM ASCF No Sleeve Impact UVDGM ASCF With Sleeve Impact 219 SGA Aquifer + SH BLA Aquifer + SH SGA Aquifer + SH BLA Aquifer + SH Synth. SGA Aquifer + SH Synth. BLA Aquifer + SH

12 Model Predicting RED Ratio Similar to RED Algorithm RED D L 1 a UVA BUVA S S DL Q C D UVA E UVA 2 Ratio 1 a UVA BUVA S S DL Q CDUVAEUVA 2 Ratio Model Should Use Statistically Significant Terms CFD Ratio Synth - BLA Synth- SGA Predicted Ratio BLA Ratio S S DL Q a 1 C D UVA SGA Ratio 1 a UVA BUVA S S DL Q CDUVAEUVA 2 12

13 Low Wavelength UV Impacts UV Dose Delivery Issue with MP systems, NOT an issue with LP systems Impact depends on: Lamp output below 24 nm Sleeve type 219 vs. 214 vs. synthetic Water UVA spectra during validation Reactor configuration Impacts pathogen disinfection and competition between UV vendors UV Sensor Systems Do Not Measure Low Wavelength UV UV sensors have max response near 26 nm, minimal response below 24 nm Online UVT monitors only measure at 254 nm At WTP, UV sensor systems will not respond to lamp aging, g, fouling and changing water UVA at low wavelengths Need to consider impact of sensor response on adenovirus and Crypto credit, and MS2 RED 13

14 Solutions to Low Wavelength Issue with MP Systems For Crypto credit, apply action spectra correction factor based on UVDGM Can be highly conservative - does not account for water UVA and reactor configuration Apply action spectra correction factor based on validated third party CFD Use Type 219 sleeves during validation For adeno credit, use low wavelength sensor systems Future Work Measure response of pathogens and validation microbes from 2 to 3 nm No data on Giardia, T1UV and T7 phage Continue work quantifying issue using CFD-based UV dose models Need a protocol for 3 rd party CFDbased calculations Develop UV sensor systems for low wavelength UV light Evaluate impact of WTP waters on correction factors 14

15 211 Water Quality Technology Conference and Exposition November 13-17, 211, Phoenix, Arizona Impact of Low Wavelength UV Light on UV Dose Monitoring with Medium Pressure UV Systems Harold Wright, Mark Heath, and Jeff Bandy Carollo Engineers, West Explorer, Suite 2, Boise, Idaho, USA Christian Bokermann and Ronnie Bemus ITT-WEDECO, Boschstrasse 4, 3213 Herford, Germany 15