Cooling Tower Maintenance Legionella Awareness

1. Cooling Tower Maintenance Legionella Awareness 3rd Installment

2. CTM/Ashland Presentations • Legionella Awareness – 2003 • Filtration of Cooling Waters – 2005 • Legionella Risk Management – 2006 • Legionella Proactive Protocol – 2008 • Literature References

3. Legionella Proactive Protocol • Introduction/Refresher • ASRAE System that may Harbour Legionella and What to Do • Risk Category • Legionella Testing Requirements • Frequency of Cleaning/Disinfection • Action Levels and Associated Response and Cleaning Steps • Cooling Tower Design Best Practice • Maintenance Considerations

4. Legionella Proactive Protocol • Implement Risk Management Criteria • Maintenance and Record Keeping • Begin now as Legislation will be forth coming • Allows for a Basis of Estimation • Man • Methods • Materials • Estimates can be Reported to Management. While Focus has been Reduction of Costs they will need Estimates as the Cost of Ownership is Going Up.

5. Refresher Information

6. Source of Legionella • Pervasive organism • Conditions for growth • 68 - 122 F (20 - 50 C) • pH 6-8 • Stagnant waters • A nutrient source • Biofilms, organics • Sediments, deposits Legionella Bacteria

7. Factors Determining the Risk of Contracting the Disease • A source of Legionella • Favorable growth conditions • Aqueous aerosol • Sufficient organisms to causeinfection • Susceptible individual

8. Field Study on Biofilm Growth

9. Effects of Cooling System Dynamics – cfu/ml Same Day Comparative Samples(Example System Treated with Continuous Oxidant and Slug Feed of Glutaraldehyde Once Per Week)

10. Action Levels • Immediate response to positive test results • On-line treatment requires a minimum of 14 days to produce results • Unrealistic a system could be totally Legionella free

11. Oxidant Feedrate

12. Systems That May Harbour Legionella

13. Systems Promoting Growth • Cooling towers • Evaporative condensers • Hot and cold water systems • Taps and showerheads • Humidifiers and air washers • Spa and whirlpool baths • Decorative fountains

14. Potable Water Supply (AWWA) • New Piping and Additions • High Velocity Flush (HVF) initially at 8-15 ft./sec. if possible • Continuous Flush at 2.5 ft/sec. • ≥ 10 ppm FAC for 24 Hours • ≥ 50 ppm FAC for 3 Hours • Slug and Hold at ≥ 100 ppm FAC for 3 Hours is an alternative

15. Potable Water Systems • Emergency Water Systems • Stagnant/Idle • Ideal Temperatures – Reach Room Temp • Eye Wash/Showers (Low to no Atomization) • Fire Systems • Periodically Flush

16. Potable Water Systems • Cold Water – Store at ≤ 20ºC (68ºF) • Hot Water - Store at 50 - 60ºC (124-148ºF) - Operate Return Water ≥ 50ºC (124ºF) • Eradication • Thermal - 66ºC to 70ºC (150ºF) for 8 hours and Flush outlets for 30 minutes • Chemical - ≥ 2 ppm (10 ppm) FAC for 2-24 hours at pH 7-8; Flush for 5 minutes • Copper/Silver Ionization, • 0.2 – 0.8 ppm Copper • 0.02 – 0.08 ppm Silver

17. Legionnella and Water Temperature

18. SPAS • Hydrotherapy Pools, Whirl Pools, Hot Tubs • pH 7.2 - 7.8; 7.4 - 7.6 Ideal • FAC 3 - 10 ppm; 4 - 5 ppm Ideal • FABr 4 - 10 ppm; 4 - 6 ppm Ideal • Ultra Violet Plus Peroxide • Ozone • Maintenance Once per day for 1 to 4 hours at 10 ppm FAC or 10X FAC in use

19. Other Water Systems • Treat and Maintain Similar to Cooling Tower Protocols • Fountains and Waterfalls • Filtration • Drain Regularly • Misters/Atomizers, Humidifiers, Air Washers • Coils, Spray Bars, Sumps, Mist Eliminators • Pre/Post Air Filtration • Bleed/Drain • Clean/Disinfect • Sludge Removal • UV – Air Space

20. RISK CATEGORY

21. Influence Risk Associated With Legionella

22. Dutch Frequency of Legionella Testing Minimum

23. Dutch Risk Category • Highest Risk – Cooling Towers < 200 meters from Hospital, Nursing Home or Health Care Facility where Occupants maybe immunologically compromised • Cooling Tower < 200 meters of Retirement Home, Hotel or Building Accommodating a Large Number of People • Cooling Tower in Residential and Industrial Neighbourhoods • Lowest Risk – Cooling Tower in Industrial Area > 600 metres Away from a Residential Area.

24. Survey of Process Risk

25. Factors Contributing to Legionella Health Risks in Cooling Systems

26. TABLE 2 – COOLING SYSTEM SUSCEPTIBILITY TO LEGIONELLA RISKS

27. TABLE 2 – COOLING SYSTEM SUSCEPTIBILITY TO LEGIONELLA RISKS

28. TABLE 2 – COOLING SYSTEM SUSCEPTIBILITY TO LEGIONELLA RISKS

29. Site Survey Pretreatment/Precleaning Need Assessment

30. Precleaning Determination DEPOSIT ANALYSIS COUPONS/SURFACES HIGHLY TUBERCULATED AND SHINY SILVER BASE LOW % IRON ON LINE BIOFILM CLEAN-UP AND STIFLING OF TUBERCLES – PLUG APPARENT POROSITY, MIXED BIO/CORROSION FOULING ON LINE BIOFILM CLEAN-UP, BIOFOULING ONLY

31. Legionella Testing Requirements

32. Survey Summary Requirements For Legionella Testing

33. Direct Testing of Legionella • Frequency Consideration • Prior to peak summer sterilization (i.e. beginning/mid August) for seasonally operated HVAC or after a sterilization. • After cleaning of a confirmed cooling tower sourced outbreak • If a confirmed outbreak has occurred in the area (≤3 km minimum) • Three times per year of 24/7 Industrial process cooling systems of higher risk noted earlier

34. Frequency of Cleaning/Disinfection

35. Frequency of Cleaning/Disinfection • Immediately prior to new system being commissioned • If the system has been out of use for one month or longer • If the system has been modified, entered or disturbed in such a way to lead to contamination • If the cleanliness of the system is any doubt • If microbiological monitoring indicates there is a problem • At least twice a year

36. Frequency of Cleaning/Disinfection • Preconditioning/Disinfection • End of Operating Season • 2 per Year Minimum for 24/7 Systems • Disinfection Only • At Peak Seasonal Demand • Occurrence of Outbreaks in the Area • Upon System Restarts of ≤ 4 weeks Idleness (≥ 3 Days?)’ • Idle System of 1 Month or More to be Drained

37. Sterilization Only • Frequency • During restart of idle/stagnant towers, condensers, heat exchangers • Seasonal restart of HVAC system, which was preconditioned and sterilized the end of the previous season • Peak of summer cooling demand (i.e. beginning of August). • Known outbreaks in the area • Biological dip slide counts exceed 105 – 106 CFU/ml. Visible slime (i.e. biofilm) present.

38. Actions Levels/AssociatedCleaning Disinfection

39. OSHA Technical Manual (Section III: Chapter 7)

40. Suggested Legionella Remedial Action Criteria

41. Implications of the Need for Biocide Improvements • Action 3 - 14 Days After Action 2 Completed • Nonoxidizers Review Dosing Schedule and Amount Used vs. Contact Time (Feed/Bleed Issues) • Oxidizer – Semi-Continuous; Frequency and Duration for 1 to 2 ppm FAC Applied. Minimum 0.5 – 1.0 ppm 4hours/24hours • Oxidizer – Continuous; 0.2 to 0.5 ppm FAC go to 0.5 – 1.0 ppm FAC • Retest within 3-5 Days

42. Implications of the Need for Biocide Improvements • Action Level 4 - 14 Days After Action Level 3 Completed • Non-oxidizer Program May Require Oxidant Use At 1/Week in Summer and 1 per 2 Weeks Winter at 1-2 ppm FAC for 1 Hour CT (i.e. 2 Hour Run Time) • Semi-Continuous Oxidizer may require either or both non-oxidizer or Biodispersant Once per Week • Continuous Oxidizer at 1-2 ppm FAC may Require Either or Both Non-Oxidizer or Biodispersant once per Week • Non-Oxidizer or Biodispersant Addition Maybe Required Every System Retention Time (Vol/BD Loss) • May Require On-line Clean Within 30 Days • Retest Within 3-5 Days

43. Implications of the Need for Biocide Improvement • Action Level 5 – 14 Days After Action Level 4 Completed • On-line Clean within 7 Days of This State • Biodispersant Plus ≥ 5 ppm FAC for 6 Hours OR • Biodispersant Plus ≥ 25 ppm FAC for 2 Hours OR • Biosdispersant Plus ≥ 50 ppm for 1 Hour • Test 3-7 Days Latter – Poor Results Repeat or Go to Off-line Approach

44. Implications of the Need for Biocide Improvement • Off-line Cleaning • Pre Conditioning with • Blowdown to ½ COC • Biodispersant and Non Oxidizer for 24 Hours • Hyper Chlorination • pH 7.5 – 8.0 • Biodispersant • ≥ 10 ppm FAC for 24 hours • Drain and Flush • Post Conditioning of ≥ 10 ppm FAC for 1 Hour • Test 3-7 Days Latter – Poor Results Repeat or Go to Wisconsin Protocol

45. Implications of the Need for Biocide Improvement • Special Notes • Action Levels Are a Forward Progression • Upon Attaining Steady State Correction Move Backwards on the Action Levels Assuring No Return to Control State Loss • It is not Unusual to have to Repeat Online or Off-line Cleans as Previous Suppressed Bioflims, Sludge and Muds have now been Conditioned/ Loosened for Release to the Bulk Water

46. OSHA/Wisconsin Protocol • Confirmed Cooling Tower Source of Outbreak • Turn off tower fans • Shock dose chlorine donor to 50 ppm FAC • Add Biodispersant • Hold 10 ppm FAC for 24 hours • Drain cooling system and repeat steps 2 - 4 • Inspect for biofilms. If present, drain and mechanically clean.

47. OSHA/Wisconsin Protocol • Refill system and operate for 1 hour at 10 ppm FAC • Flush system • Recharge system with water treatment additives for deposit, corrosion and biological control and return to service Note test monthly: • Legionella ≤10 CFU/ml • HPC ≤10^5 CFU/ml

48. Action Levels of One JCAHO Facility Cooling Tower Upwind from Building Air Intakes

49. Cooling Tower DesignBest Practices

50. Sand Filtration 5 Micron Media