1. 5/21/2015Disinfection1 Disinfection: Microbiology and Chemistry J(Hans) van Leeuwen

2. Disinfection2 Introduction Need for disinfection Alternative disinfectants Disinfection kinetics Disinfectant chemistry

3. Disinfection3 Topics of Discussion Diseases borne by water Comparison of disinfectants The Ct concept

4. Disinfection4 Some common water-borne diseases prevented by disinfection Bacterial Viral Protozoan Typhoid fever Para-typhoid Bacterial diarrhea Cholera Legionnaires’ disease Hepatitis Rotavirus diarrhea Amoebiasis Giardiasis Crypto- sporidiasis

5. The rate of disinfection Disinfection5 Like most biological processes, disinfection follows a first-order reaction with respect to the number of microbes of a certain species surviving as a function of time at a constant level of a disinfectant - dN/dt = kN, which is also known as Chick’s Law dN/N = - kdt (separating variables) ln N/N o = - kt or N = N o e -kt (from integration)

6. Disinfection6 The Ct Concept In disinfection, the ability to inactivate microorganisms is a function of both disinfectant concentration and time. Fractional removal, N/N o = C n t m This is generally simplified to N/N o = Ct Ct values have been determined for 99.99% virus and 99.9% Giardia removal

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8. Ozone Ct values Disinfection8 Microorganism Ct (mg min l -1 ) T ( o C) pH log reduction E.coli 0,00912*4 log Legionella pneumophila 1,0512*2 log Rotavirus 0,006-0,0656-72 log Giardia lamblia (cysts) 0,17257.22 log Giardia muris (cysts) 0,272572 log Cryptosporidium parvum (oocysts) 5,39**20*2 log

9. Disinfection9 Chlorination

10. Disinfection10 Chlorinator

11. Disinfection11 Chlorine gas flow control

12. Disinfection12 Chlorine contact tank with baffles

13. Disinfection13 Gravity fed chlorine solution feeder

14. Disinfection14 Gravity fed chlorine solution feeder

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18. Disinfection18 Ultraviolet Irradiation

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21. Disinfection21 Simple Solar Disinfection

22. Disinfection22 Solar Disinfection

23. Disinfection23 Ozonation

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29. Disinfection29 Biomass bulking control

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35. Disinfection35 Effect of ozonation on sludge settling

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38. Disinfection38 Selective oxidation

39. MeBl oxidation Disinfection39

40. Effect on protozoa Disinfection40

41. Disinfection41 Ships’ Ballast Water Disinfection NUTECH O3, NOAA, NETSCO, UNCW, UWS, ISU, et al.

42. Disinfection42 Alien Invaders in our Coastal Waters - weirder and risky

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44. Disinfection44 Zebra Mussel Distribution

45. Disinfection45 San Francisco Bay: 212 exotic species and 140 more suspected

46. Disinfection46 Cross section of ships showing ballast tanks and ballast water cycle

47. Disinfection47 Propeller exposed under unballasted conditions

48. Disinfection48 Into the Tonsina’s ballast tanks

49. Disinfection49 View of ballast tanks from below

50. Disinfection50 Interconnectivity of ballast tanks in sideview

51. Disinfection51 INSIDE THE OZONE GENERATOR ON THE TONSINA

52. Disinfection52 Side-stream ozone injection

53. Disinfection53 Ozone Reactions in Seawater 1. O 3 + Br -  OBr - + O 2 2. OBr - + O 3  2O 2 + Br - 3. OBr - + O 3  BrO 2 - + O 2 4. BrO 2 - + O 3  BrO 3 - 5. H + + OBr -  HOBr HOBr main contribution to total residual oxidant (TRO)

54. Disinfection54 TRO Decay with time Decrease in TRO (mg/L Br 2 ) in unfiltered Puget Sound seawater over time, starting at 2.0, 3.0 and 4.0 mg/L Br 2. Data are the mean + SD of four replicates.

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