+ O - FH Münster
Transcription
+ O - FH Münster
UV-Strahlungsquellen für die Wasseraufbereitung Anwendung in der Trink-, Prozess- und Abwasserbehandlung Thomas Jüstel [email protected] Münster 03. Mai 2006 FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Outline • Introduction • UV Radiation: Effects and Applications • UV Radiation Sources • Treatment of – Drinking water – Waste water – Process water • Future Trends FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Dynamic of Worldwide Water Use 6000 water consumption / 109 m3 5000 agriculture industry household total Facts and Figures • during the last 100 years worldwide water consumption increases twice as fast as world population • 0.6% of the global water resources is available as drinking water 4000 • 1.2 billion people have no access to safe drinking water 3000 • 3 billion people suffer from diseases caused by contaminated water 2000 • unclean water kills more than 2 million people, mostly children, each year 1000 0 1900 FH Münster, FB 1 Prof. Dr. T. Jüstel 1950 year 2000 2050 Increasing demand for efficient + low cost water treatment technologies UV Radiation Sources for Water Treatment Worldwide Disinfection Market 1999 2500 Mio. € 2005 3800 Mio € Chlorination 55% Chlorination 83% Ozone, Filtration,... 5% Ultraviolet 12% Ozone, Filtration,... 15% Ultraviolet 30% • Moderate total market growth (7% p.a.) • Strong tendency to replace chlorine based systems • UV/ozone segments are growing super-proportionally FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Technology Benchmark 0.5 costs [€/m3] 0.4 0.3 0.2 0.1 0 Ultraviolet Chlorine Ozone Filtration Source: “Desinfektion von biologisch gereinigtem Abwasser”, Merkblatt ATV-M 205, Deutsche Gesellschaft für Wasserwirtschaft, Abwasser und Abfall e.V. (1998) FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Advantages of UV Radiation • Direct method (effective, economic) • Easy installation • Broad range of microorganisms can be inactivated (e.g. Cryptosporidium parvum oocysts, Giardia muris) • Safe and easy handling, storage, shipping (no harmful chemicals) • Minimum formation of disinfection by-products (DBPs) • No influence on odour and/or taste • No concentration and accumulation of viruses, bacteria or contaminants FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment UV-Radiation: Effects and Applications 100 nm UV-B UV-C VUV 200 nm 280 nm UV-A 320 nm 12.5 - 6.9 eV 6.9 – 4.5 eV Cleavage of H2O and O2 into radicals Ozone formation Cleavage of C-C, CH, C-O bonds Excitation of C=C bonds Excitation of nucleobases Cleavage of O3, ClO2 and H2O2 Vitamin D production Transcription of repair enzymes Cleavage of O3 and NO2 Photocatalytic reactions Melanin oxidation Decomposition of organic pigments Ultra pure water TOC reduction Wafer cleaning Photochemistry Disinfection of H2O and air Photochemistry X-ray imaging additive removal Psoriasis treatment Tanning Water and air purification by TiO2 photocatalyst Tanning FH Münster, FB 1 Prof. Dr. T. Jüstel 4.5 - 3.9 eV 400 nm 3.9 – 3.1 eV UV Radiation Sources for Water Treatment UV-Radiation: Photochemistry by VUV Effects on water on air components 1. Photochemical cleavage of water H2O + hν(< 200 nm) → OH. + H. 2 OH. → H2O2 2 H2O2 → 2 H2O +1O2 2. Ozone formation O2 + hν(< 200 nm) → 2 O. 2 O2 + 2 O. → 2 O3 3. Photochemical cleavage of carbon dioxide CO2 + hν(< 230 nm) → CO + 1O 4. Photochemical cleavage of nitrate anion NO3-+ hν(< 240 nm) → NO2. + O.Cleavage of Nitrogen occurs at wavelength < 120 nm FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment UV-Radiation: Photochemistry by UV-C Effects on H2O2 and O3 Extinktionskoeffizient H2O2 1. Cleavage of H2O2 into OH radicals (H2O2/UV process) H2O2 + hν(< 280 nm) → 2 OH. 160 140 120 2. Conversion of Ozone into H2O2 O3 + H2O + hν(< 330 nm) → H2O2 + O2 H2O2 + hν(< 280 nm) → 2 OH. Formation of OH. radicals is the key to Advanced Oxidation Processes (AOPs): OH. + M → OH- + M+ FH Münster, FB 1 Prof. Dr. T. Jüstel 100 80 60 40 20 0 200 210 220 230 240 250 260 270 280 290 300 Wavelength λ [nm] UV Radiation Sources for Water Treatment UV-Radiation: Disinfection by UV-C Biochemical background Rel. efficiency/absorption 1,0 H O P Disinfection efficiency (DIn 5031-10) O Absorption spectrum of dTMP N C N C 0,8 C O C CH3 H 0,6 P O 0,4 C N 0,2 H O P 0,0 200 250 300 O 350 FH Münster, FB 1 Prof. Dr. T. Jüstel Extinction coefficient ε at 260 nm 15200 lmol-1cm-1 8400 lmol-1cm-1 12000 lmol-1cm-1 7100 lmol-1cm-1 N NH C H O O C N C H C O C CH3 H P C O C CH 3 C C N Wavelength [nm] Nucleotide dAMP dTMP dGMP dCMP H O N C C O CH3 UV Radiation Sources for Water Treatment UV-Radiation: Application in Water Treatment UV disinfection (240 - 280 nm) • domestic tap water • municipal drinking water facilities • surface water • waste water disinfection • process water (food / beverage industry) Photo-initiated oxidation techniques (< 240 nm) • oxidation/mineralization of toxic organic contaminants • ultra pure water production • drinking / process water treatment • ground water remediation • treatment of waste water (e.g. from hospitals) FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment How much UV Radiation? Standards and regulations • NSF/ANSI Standard 55 (US) • Class A (safe level): 40 mWs/cm2 • Class B (supplement): 16 mWs/cm2 • DVGW (Germany) • 400 J/m2 (254 nm) • verification with test organism (E. coli, B. subtilis) • reduction of 99.99 % = log 4 Some affecting factors • Water flow / water quality • Reactor design • Lamp aging / performing • Fouling of sleeve • Type of microorganism (radiation hardness, photoreactivation, etc…) Photoreactivation is a process whereby dimerized pyrimidines (usually thymines) in DNA are restored by an enzyme (deoxyribodipyrimidine photolyase) FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Disinfection Efficacy - Parameters Reactor • Geometry • Volume flow rate ⇒ Residence time Water • Quartz tube fouling • Turbidity, particles • Water matrix Lamps • • • • • Total lamp power Spectrum Degradation Power density T-dependence UV dose / Jm2 Microorganism • UV sensibility • Photo-reactivation • Reproduction rate FH Münster, FB 1 Prof. Dr. T. Jüstel Reduction rate UV Radiation Sources for Water Treatment Types of UV Radiation Sources Sunlight > 300 nm Solar UV spectrum UV-B UV-A Hg discharge lamps • low pressure • amalgam • medium pressure -2 -1 Spectral irradiance [Wm nm ] 1,0 185, 254 nm 185, 254 nm 200 – 400 nm 0,8 0,6 0,4 0,2 0,0 280 Excimer LASER Solar radiation at 60° sun height (clear sky) 300 320 Excimer lamps (DBD) • Xe2* • KrCl* • XeBr* • XeCl* 172 nm „fluorescent DBD“ 222 nm 282 nm 308 nm (Al,Ga)N LEDs 260 – 380 nm FH Münster, FB 1 Prof. Dr. T. Jüstel 340 360 380 Wavelength [nm] UV Radiation Sources for Water Treatment 400 Low Pressure Hg Discharge Lamps Desired Glass tube Hg discharge Phosphor excited layer Hg atom Hard UV Radiation Purification FH Münster, FB 1 Prof. Dr. T. Jüstel spectrum Radiation from discharge electrode electrons Phosphor Disinfection cap Soft UV Radiation Photochemistry + Photobiology UV Radiation Sources for Water Treatment Low Pressure Hg Discharge Lamps Lamp spectrum Temperature dependence 254 nm 1,0 Mercury Low Pressure Discharge Efficiency Pure Mercury 90 0,8 BiIn Amalgam 80 Relative Efficiency / % Emission intensity [a.u.] 100 0,6 0,4 70 60 50 40 30 20 10 0,2 185 nm 0 0 365 nm 0,0 100 200 300 Wavelength [nm] 10 20 30 40 50 60 70 80 Temperature / °C 400 • Highest light output at 40°C gas temperature (coldest spot) • Designed for 25°C ambient temperature • 85% emitted at 253.7 nm, 12% at 185 nm, rest at 365 nm and in the visible range • Typical lifetime: 10.000 h FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Medium Pressure Hg Discharge Lamps • • • • Main emission in the UV-A/UV-B range and visible radiation Semi-continuum in the UV-C Operation temperature: 600°C - 800°C High power (density) + compact design ⇔ lower efficiency FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment State-of-the-art UV Radiation Sources UV-C wavelength typical lamp power lamp efficiency GAC factor UV-C power per length wall temperature Low Pressure Hg Amalgam Medium Pressure Hg 254 nm 254 nm 200 - 280 nm 4...100 W 100...300 W 1...17 kW < 40 % 30...35 % 10...15 % 85 % 85 % 80 % 0.2 W / cm 0.7 W / cm 15 W / cm 40 °C 100 °C 600 - 900 °C ⇒ selection based on life cycle cost FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment UV Radiation Application Areas • • • • Municipal drinking water Private households (POU / POE) Swimming pools / spas Ships • • • • • • Food / beverage industry Pharmaceutical industry Personal care products (e.g. cosmetics) Semiconductor / microelectronic industry Aquaria Aquaculture / fish farms • • • Municipal waste water Industrial waste water Hospital waste water FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Municipal Drinking / Waste Water Goal: Inactivation of microorganism • • • • • • Driven by government regulations Disinfection by-products (drinking water) Replacement of chlorination systems Life cycle costs and system performance critical Installation sizes up to 7.6.106 m3/day Only few global players on the market FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Municipal Drinking Water Location: Helsinki, Finland Flow rate: 12.500 m3/h UV Power: ∼ 22 kW Number of lamps: ∼ 170 Power/lamp: ~ 130 W FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Waste Water Treatment Location: Bad Toelz, Germany Flow rate: 200 … 2000 m3/h UV Power: 18 kW Number of lamps: 144 FH Münster, FB 1 Prof. Dr. T. Jüstel Location: Manukau, New Zealand Flow rate: 50.400 m3/h UV power: min. ~ 320 kW Number of lamps: ~ 2500 UV Radiation Sources for Water Treatment Industrial / Commercial Process Water Goal: Disinfection and TOC reduction • • • • • More diversified market Compact installations Relatively low flow rates High level of purity Industrial/commercial customers – Food beverage – Micro electronics – Bio pharmaceutical – Hospitals – Fish farms – Hydroponics – etc… FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment End Consumer Market Goal: Purification of domestic drinking water • • • • • POU / POE Applications Very diversified market Small flow rates or batch processes Discontinuous use Driving market forces – Safety – Handling – Design – Marketing – Sales channels FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Future Trends 1. Advanced Oxidation Processes „More than only disinfection“ 2. Incoherent Excimer Lamps „Novel UV sources for novel applications“ FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment 1. Advanced Oxidation Processes Approach - direct photolysis of contaminants - production of oxidizing intermediates mainly •OH Laws of photochemistry • „Only the light that is absorbed by a molecule can be effective in producing photochemical change in the molecule“, Grotthus-Draper Law (1817, 1843) • „Each molecule taking part in a chemical reaction absorbs (at least) one quantum of radiation (photon), which causes the reaction“, Stark-Einstein Law (1912) • „The energy of an absorbed photon must be equal or greater than the weakest bond in the molecule“, conservation of energy FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment 1. Advanced Oxidation Processes Homogeneous catalysis a) VUV water photolysis H2O + hν → H. + OH. b) UV + ozone O3 + hν → O2 + O(1D) O(1D) + H2O → [OH. + .OH] → H2O2 H2O2 + hν → 2 OH. c) UV + hydrogen peroxide H2O2 + hν → 2 OH. Oxidizing agent Oxidation potential [V vs NHE] Fluorine 3.03 Hydroxyl radical 2.80 Atomic oxygen 2.42 Ozone 2.07 Hydrogen peroxide 1.78 Perhydroxyl radical 1.70 Hypobromous acid 1.68 Chlorine dioxide 1.57 Hypochlorous acid 1.49 Chlorine 1.36 d) UV/Vis Fenton processes Heterogeneous catalysis • TiO2 + UV/Vis (+H2O2) FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment 1. Advanced Oxidation Processes Contaminants and Waste Treated by AOPs amino acids antibiotics arsenic chromium coliforms cyanide disinfection by-products distillery wastewater hospital wastewater insecticide landfill leachat municipal sludge FH Münster, FB 1 Prof. Dr. T. Jüstel natural organic matter oilfield wastewater olive mill wastewater paper mill effluent phenolic wastewater printing wastewater rubber process wastewater seed corn wastes spent caustic tannery wastewater volatile organic compounds (VOCs) x-ray contrast media UV Radiation Sources for Water Treatment 2. Incoherent Excimer Lamps Basic physical principle • formation of excited dimers (excimer) in the gas phase (or excited complexes (exciplexes), e.g. in OLEDs) • gas pressure: 100 mbar....1 bar (high pressure lamps) Lamp driving (energy in-coupling) • by microwaves • by dielectric barrier discharge non-thermal plasma Typical gas fillings • rare gases • halides • rare-gas/halide mixtures FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment 2. Incoherent Excimer Lamps Excimer Forming Gases or Gas Mixtures Pure Halide Ar Kr Xe FH Münster, FB 1 Prof. Dr. T. Jüstel F Cl Br I Noble Gas 158 nm 258 nm 293 nm 342 nm - - Ar*2 ~10% 126 nm > 10% 193 nm > 10% 248 nm > 10% 351 nm ca. 5% 175 nm 18% 222 nm 14% 308 nm < 0.1% 161 nm ca. 5% 207 nm 15% 282 nm < 0.1% 185 nm Kr*2 ~15% 146 nm ca. 5% 253 nm Xe*2 30% 172 nm UV Radiation Sources for Water Treatment 2. Incoherent Excimer Lamps Dielectric barrier microdischarges generating excimer radiation HV-electrode (semi-transparent) u(t) discharge gap dielectric layer (glass, quarz) Xe filling UV-R characteristic parameters tMD ≈ 10 ns pressure 1 bar 172 nm gap 1 mm – 1 cm Egap 0.1 – 100 kV / cm Telectron 1 – 10 eV 1014 cm-3 nelectron degree of ionization 10-4 f 50 kHz dielectric layer (glass, quarz) counter electrode FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment 2. Incoherent Excimer Lamps Advantages of DBD driven Xe excimer discharges • Instant start • Temperature independent • Flexible design • Specific output spectrum • High power density Reaction scheme Xe + e- → Xe(3P2) + e- Xe(3P2) + 2 Xe → Xe2(3Σu+) + Xe Xe2(3Σu+) → 2 Xe + hν172 nm FH Münster, FB 1 Prof. Dr. T. Jüstel XERADEX (Radium) Present application areas • Plasma display panels (PDPs) • Lamps for scanners and copiers • Surface cleaning • Ozone production (Siemens) • Water treatment UV Radiation Sources for Water Treatment 2. Incoherent Excimer Lamps DBD driven Xe-excimer discharge lamp for water treatment Optimised lamp design • solely 172 nm radiation (quartz) • FWHM ~ 14 nm • Radiant efficiency ~ 40% at 20 or 100 W of electrical input power 15 – 25 kW XeCl* excimer lamps are in use From: T. Oppenländer, E. Sosnin, IUVA News 7 (2005) 16 FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment 2. Incoherent Excimer Lamps Normalized emission intensity Hg low pressure discharge lamp UV Phosphor layer 254 nm 1,0 185 nm 254 nm 0,8 0,6 0,4 0,2 185 nm Desired lamp spectrum 0,0 200 300 400 500 600 Wavelength [nm] Xe2* excimer discharge lamp 172 nm Wavelength [nm] FH Münster, FB 1 Prof. Dr. T. Jüstel 2 nd Continuum 1st Continuum Resonance Line Emission intensity 147 nm 150 nm 150 nm 172 nm German Patent DE 199 19 169.7 Lamp glass UV Radiation Sources for Water Treatment 2 nd Continuum 1st Continuum Resonance Line 147 Xenon Excimer 10 -7 10 H2O 1 -1 -6 10 -5 10 -4 10 -3 10 -2 10 160 170 180 190 200 10 0 10 Wavelength [nm] to improve penetration depth FH Münster, FB 1 Prof. Dr. T. Jüstel Penetration depth [m] Absorption coefficient [m-1] -8 10 7 10 6 10 5 10 4 10 3 10 2 10 10 0 10 150 emission spectrum convert to 200 - 280 nm convert to 190 - 200 nm 8 Xe excimer 172 Wavelength [nm] Rel. efficiency/absorption Intensity [a.u.] Phosphor Conversion of Xe Excimer Radiation Disinfection efficiency (DIN 5031-10) 1.0 0.8 0.6 0.4 0.2 0.0 200 220 240 260 280 300 320 Wavelength [nm] to improve GAC overlap UV Radiation Sources for Water Treatment Philips Project “UV-C Phosphors” since 07/05 Project goals Development and optimization of novel UV-C phosphors for fluorescent lamps based on Xe2*-Excimer discharges Find UV-C phosphors with a large GAC overlap ⇒ Pr3+ activated phosphors 1,0 Germicidal Action Curve LaPO4:Pr 225 nm 0,8 Lamp spectrrum of a DBD lamp with YPO4:Pr YPO4:Pr 233 nm LuBO3:Pr 257 nm YBO3:Pr 261 nm Intensity (a.u.) 1. 0,6 0,4 0,2 Y2SiO5:Pr 270 nm 0,0 200 250 300 Wavelength [nm] FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment 350 Philips Project “UV-C Phosphors” since 07/05 Project goals 2. Optimise efficiency and stability of materials with high GAC overlap Present status • Phosphor efficiency ~ 90 … 100% • Lamp efficiency ~ 20 … 25% • Phosphor stability improvement measures Highly efficient, pulse driven Xe excimer discharge lamp comprising a UV-C phosphor under development to achieve 10000 h lifetime FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment Acknowledgement FH Münster Dr. Julian Plewa Philips Research Aachen and Philips Lighting Roosendaal Dr. Wolfgang Schiene Dr. Arjan van der Pol Thanks for your attention! FH Münster, FB 1 Prof. Dr. T. Jüstel UV Radiation Sources for Water Treatment
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