Chlorine Dioxide Presentation for Illinois Rural Water Association

4. Oxidation/Reduction Potentials Compound ORP (Volts) Oxidation Capacity Ozone (O3) 2.07 2 Electrons Hydrogen Peroxide (H2O2) 1.76 2 Electrons Hypochlorous Acid (HOCl) 1.49 2 Electrons Chlorine (Cl2) 1.36 2 Electrons Hypobromus Acid (HOBr) 1.33 2 Electrons Chlorine Dioxide (ClO2) 0.95 5 Electrons

5. Comparison of Disinfectant Oxidation Potentials (EOP) of Various Oxidants ClO 2 reacts by oxidation, but is not a strong oxidizer Why does ClO 2 work so well at low doses?

10. Heterogeneity of Biofilm structure and function

12. 3 step Biofilm life cycle

14. Attachment Surface Bulk Water ClO 2 S-S ClO 2 - ClO 2 H + Catalytic ClO 2 Chemistry in Biofilm Sodium Chlorite/Chlorate Sodium Chlorite/Chlorate

15. Dissociation vs. pH pH 100 90 80 70 60 50 40 30 20 10 0 7 8 9 10 1 1 12 13 14 HOBr OBr - HOCl OCl- Percent Hypohalous Acid ClO 2 pH % HOBr % HOCl % ClO 2 7.5 8.0 8.5 9.0 94 83 60 33 48 22 9 3 100 100 100 98 2 ClO 2 ClO 2 - + ClO 3 -

21. PureLine ® HP-Series Generators Electrochemical ClO 2 Production: Anode: ClO 2 -  ClO 2 + e - + Na + Cathode: H 2 O + e -  1/2 H 2 + OH - Na + + OH -  NaOH

22. PureLine ™ HP-Series Electro-chemical ClO 2 Generator Electrochemical Production of Chlorine Dioxide: Anode: ClO 2 - ----> ClO 2 + e - Cathode: H 2 O + e - ---> 1/2 H 2 + OH - (0.1%H 2 ) Na + + OH - ---> NaOH

25. Electrochemical CIO 2 Operational Costs Electrical Consumption Per Pound of ClO 2 55 watts per lb. Chlorine Dioxide $0.085/KWH = $7.14 per day electrical usage PureCide 25 TM solution Consumption 6.6 lbs Per Pound of ClO 2

35. Typical ClO 2 Feed Point SOURCE WATER SILT & MUD TANK PRIMARY SETTLING BASIN SECONDARY SETTLING BASIN FLOCCULATION BASIN (SLOW MIXER) COAGULATION BASIN (FLASH MIXER ) CLEAR WELL COAL & SAND FILTER BAR SCREENS CHLORINE DIOXIDE LOW LIFT PUMPS SLUDGE DISPOSAL TO CANAL SLUDGE RETURNED TO CANAL CHLORINE HIGH LIFT PUMPS TO DISTRIBUTION SYSTEM LIME IRON CARBON POLY-ELECTROLYTES

38. Pure ClO 2 Results

39. Chlorine “Chlorinates”, Chlorine Dioxide “Oxidizes” HOCl + Organic  Cl-Organic (THM/HAA/AOX) ClO 2 (O=Cl=O) + Organic  O-Organic (-) O 3 (O-O-O) + Organic  O-Organic (-)

42. Conclusions The City of Greenville was faced with unacceptably high concentrations of DBPs due to pre- and post-chlorination of surface water.

43. Conclusions ClO 2 chosen over alternatives: - increased CT-credits - improved DBP reduction - eliminated KnMnO4 & Carbon - improved operator safety - simplicity of feed

44. Conclusions Pre-disinfection with pure ClO 2 provided a very cost-effective means for dramatically reducing DBP levels while improving the microbial control, turbidity, taste and odor with a reduction in chemical use resulting in a 3.5 – 4 year ROI.

46. Questions? PureLine Treatment Systems www.pureline.com