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205 Webster Street Bethlehem, PA 18015 888-610-2562 cdgenvironmental

Application of Chlorine Dioxide in Drinking Water. 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com. Introduction. Chlorine dioxide (ClO 2 ) Powerful, selective oxidant Drinking water treatment > 50 years Must be produced on site

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205 Webster Street Bethlehem, PA 18015 888-610-2562 cdgenvironmental

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  1. Application of Chlorine Dioxide in Drinking Water 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  2. Introduction • Chlorine dioxide (ClO2) • Powerful, selective oxidant • Drinking water treatment > 50 years • Must be produced on site • A leading alternative to chlorine for oxidation and disinfection 2 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  3. Chlorine Dioxide • Very volatile and reactive • Unstable at high concentrations • Gas highly soluble in water • Oxidizes, does not chlorinate • Selective, one-electron transfer • Does not react with ammona 3 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  4. Chlorine Dioxide • Potable water • Odor and taste control • Metals removal • THM reduction/elimination • Removal of chlorine-resistant pathogens • Mollusk control • Zebra mussels • Process-water • Biocide • Metals removal • Wastewater • Oxidation of waste products • Color removal • Gas sterilization of medical products • Decontamination 4 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  5. Drinking Water Issues • Health effects • Chlorinated organics (THM, HAA) • Chlorine-resistant pathogens (Cryptosporidium, Gardia lamblia) • Water quality • Taste, odor & color • Dissolved metals • Regulations • EPA-M/DBP Rule (Phase 1) requires compliance by December 15, 2001 5 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  6. ClO2 Benefits • Does not form chlorinated DBPs (THM, HAA) • Does not oxidize bromide ion to bromate ion • Broad spectrum microbiocide • Inactivates Giardia & Cryptosporidium • Improves sedimentation and filtration • Lowers turbidity 6 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  7. ClO2 vs. Chlorine • No cancer-causing by-products formed • Kills chlorine-resistant pathogens • Superior manganese oxidation • Typical ClO2 dose ~ 0.25 - 1.5 ppm • Typical Cl2 dose ~ 2.0 - 5.0 ppm 7 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  8. ClO2 vs. Ozone • Fewer by-products (e.g., bromate) • Lower cost (capital, power) • Superior manganese oxidation • Minimal power requirements 8 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  9. Chlorine Dioxide Historical Limitations • Inefficient and unreliable generators • Difficult and complicated analytical methods • Odor problems “at the tap” • Toxicology “data gaps” • Unclear regulatory prospects 9 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  10. Pathogen Regulations DBP Regulations Drinking Water Regulations • Cryptosporidium: 99% removal • Giardia lamblia: 99.9% removal Toxicology Data • Bromate: 0.01 PPM • Chlorite: 1 PPM • TTHM: 0.08 PPM • HAA: 0.06 PPM 10 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  11. Chlorine Dioxide Generation Methods • Sodium chlorate (NaClO3) • Paper pulp bleaching • Very large-scale production • Sodium Chlorite (NaClO2) • Drinking water treatment, since 1944 • Wastewater treatment • Industrial process water treatment • Medical device sterilization • Decontamination 11 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  12. Chlorine Dioxide Sodium Chlorite-based Generation Methods • Acid : Chlorite Solution • Chlorine Solution : Chlorite Solution • Chlorine Gas : Atomized Chlorite Solution • Chlorine Gas:SolidTM Chlorite Process 12 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  13. Chlorine Dioxide Chlorite Solution Generation Method • Oldest sodium chlorite generation method • Maximum yield limited to 80% • Chlorine dioxide concentration in product variable based on: • Sodium chlorite solution concentration • Acid concentration • pH of reaction • Presence of chloride ion • Highly inefficient and unreliable 13 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  14. Chlorine Dioxide Chlorine Solution : Chlorite Solution • Excess chlorine is needed to neutralize NaOH in product • High conversion, but yield limited to 80% to 90% • Very corrosive effluent due to low pH • Multiple feed chemical systems required (chlorine gas, chlorine solution or hypochlorite and chlorite solution) • Slow mixing of reagents increases chlorite and chlorate production while decreasing yield 14 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  15. Chlorine Dioxide Chlorine Gas : Vaporized Chlorite Solution • State of the art technology prior to Gas:SolidTM system introduction • Rapid mixing of reagents improves purity and yield • Frequent adjustment, re-calibration and cleaning required to minimize chlorite and chlorate production • Liquid chemical feed system • Difficult to apply in small applications • Chlorite and chlorate in product make analysis difficult 15 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  16. Chlorine Dioxide Generator Historic Limitations • Poor turndown capabilities • Re-calibration required when shut down and restarted • Unsuited for small plants • Generators operated with excess chlorine to create the appearance of high yield 16 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  17. Chlorine Dioxide Generator Historic Limitations • Feedstock/chlorites deteriorate, requiring constant analysis • Accurate yield/efficiency/purity analysis required-5-step titration of product • By-product concerns 17 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  18. Chlorine Dioxide Generator Historic Limitations • Yield calculation must account for ALL Oxy-chlorine species Chlorine Dioxide Chlorine Dioxide + Chlorite + Chlorate + Chlorine 18 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  19. Chlorine Dioxide Chlorine Gas:SolidTM Chlorite Process • Developed by CDG Technology, Inc. • Most advanced generation technology available • Product is pure chlorine dioxide gas • No chlorite or chlorate ions produced by generator • Infinite turndown capability without need for re-calibration • Effluent analysis need account only for chlorine dioxide and chlorine 19 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  20. Chlorine Dioxide Generator Historic Limitations “...this [Gas:Solid] process resolves essentially all of the problems associated historically with chlorine dioxide generation...” —George Clifford White, Handbook of Chlorination and Alternative Disinfectants, 4th Edition, 1999 20 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  21. SOLUTION OUT SCALE CHLORINE AIR AIR CHLORINE DIOXIDE + AIR FILTER EJECTOR RAW WATER IN SAF-T-CHLOR SOLID SODIUM CHLORITE SAF-T-CHLOR SOLID SODIUM CHLORITE SCALE CHLORINE Gas:SolidTM Plant-Scale Chlorine Dioxide Generators Cl2 + 2NaClO2 2ClO2 + 2NaCl Chlorine Sodium Chlorite Chlorine Dioxide Sodium Chloride 21 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  22. Gas:SolidTM Plant-Scale Chlorine Dioxide Generators 22 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  23. Gas:SolidTM Plant-Scale Chlorine Dioxide Generators 23 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  24. Chlorine Dioxide Generation Method Considerations • Chlorine dioxide by-products • Chlorite ion: ClO2 • Chlorate ion: ClO3 • Two sources of by-products • Inherent with chlorine dioxide use • Un-reacted sodium chlorite feedstock 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  25. Chlorine Dioxide Generation Method Considerations • Chlorite/Chlorate ion avoidance and removal • Generator maintenance and calibration: All except Gas:SolidTM process • Generator selection: type, size, etc. • Reducing agents - ferrous salts, sulfite • Limit amount of contaminants in feedstock (liquid systems) • Limit chlorine over-feed (liquid systems) 25 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  26. Chlorine Dioxide Safety Considerations • Unstable under pressure and in high concentrations (>15%) • Never stored or shipped • Strong aqueous solutions will release chlorine dioxide gas • OSHA maximum exposure limit over 8 hrs. in 0.1 ppm-also odor threshold 26 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  27. Chlorine Dioxide Conventional Generator Safety Considerations • Chemical feed systems • Materials of construction (storage tanks, pumps, piping) • Containment and spill protection • Personnel protective equipment • Contact with chemicals • Generator Operation • Proper calibration and adjustment of feed chemicals • Personnel protective equipment • Contact with chemicals 27 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  28. Chlorine Dioxide Gas:SolidTM Generator Safety Considerations • Chemical handling • Process designed to eliminate contact with chemical • Sodium chlorite shipped in sealed cartridges • Maximum worker safety • Safety interlocks • Low vacuum • Low air flow • Excessive chlorine gas flow • Low ambient temperature • Combustible gas presence • Solid sodium chlorite formulation 28 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  29. Sodium Chlorite Safety Considerations Fuel Fire Ignition Source Oxidant Triangle • Sodium chlorite is a strong oxidizer 29 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  30. Sodium Chlorite Gas:SolidTM Generator Safety Considerations • Fuel exclusion • Sealed chemical cartridges • Ceramic internal cartridge components • No external handling after production • Air and chlorine gas pass through ultra filtration • Combustible gas detector • Sodium chlorite formulation 30 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  31. Sodium Chlorite Gas:SolidTM Generator Safety Considerations • CDG Saf-T-ChlorTM sodium chlorite • Specially formulated • Minimizes possibility of ignition source • Absorbs and dissipates heat • Does not propagate and ignite 31 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  32. Gas:SolidTM Generator Safety Review • Vacuum feed • System shuts down with loss of vacuum • Saf-T-ChlorTMdoes not auto-degrade under excessive heat conditions • No direct contact with chemical • Closed system • No chemical mixing • No chemical leaks 32 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  33. Chlorine Dioxide Summary Guidelines • Set clear ClO2 treatment goal • THM & HAA avoidance • Taste, odor & color control • Disinfection CT • Oxidation (iron & manganese) • Define use conditions • pH • Temperature • Contact time 33 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

  34. chlorine dioxide, pure and simple 34 205 Webster Street Bethlehem, PA 18015 888-610-2562 www.cdgenvironmental.com

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