The Impact of Ozone as a Secondary Disinfection System


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The Impact of Ozone as a Secondary Disinfection System

  1. 1. OzoneSecondary Disinfection System forPublic Swimming VenuesUnder MAHC Compliance January 1, 2013
  2. 2. Public Health Responsibility• Swimming is the third most popular sport in the United States; encompassing all age groups• It is estimated that there are about 360,000 public pools in the U.S.• Considering that most public swimming venues are essentially communal baths, there is an enormous task to protect public health from communicable diseases and other health hazards• Approved technologies currently available to help provide a safe and healthy aquatic experience to all swimmers should not be ignored 2
  3. 3. Cryptosporidium parvum Outbreaks 136 outbreaks of cryptosporidiosis worldwide from 1988 to 2004 (68 in U.S.) with 92% in disinfected venues - Centers for Disease Control in Atlanta - 2008 reported 10,500 cases 3
  4. 4. Water Quality Issues andCryptosporidium parvum Outbreaks• CDC swimming pool surveillance reports show that of the 21,500 inspections conducted between May and September of 2002, water chemistry violations were found at 38.7% of these facilities, 14.3% of the violations were for inadequate disinfection levels at therapy pools (CDC Surveillance Data from Swimming Pool Inspections --- Selected States and Counties, United States, May – September 2002. 2003. MMWR 52(22); 513-516)• During 2008, inspectors in 15 jurisdictions performed 120,975 inspections and found 12,917 (10.7%) identified disinfectant level violations (CDC Surveillance Data from Swimming Pool Inspections --- Selected States and Counties, United States Morbidity and Mortality Weekly report (MMWR) May 21, 2010 / 59(19);582-587)• In one of the largest outbreaks reported, approximately 2,300 persons developed cryptosporidiosis following exposure to a New York spray park (Surveillance for Waterborne Disease and Outbreaks Associated with Recreational Water Use and Other Aquatic Facility -- Associated Health Events --- United States, 2005—2006 MMWR Surveill Summ. September 12, 2008 / 57(SS-9);1-38) 4
  5. 5. Recreational Water Illness• Chlorine has been the standard water treatment chemical for public pools since 1961 (U.S. Public Health Service)• Chlorine is effective in reaching certain water quality standards, however scientists are learning more about its limitations and hazards in public swimming venues• Recreational Water Illness (RWI) has become wide spread in the US in public pool venues and is increasing annually; posing a significant public health and liability risk• RWI is a term coined by the Centers for Disease Control and Prevention (CDC) to describe illnesses caused by microorganisms as well as those from chloramines – Some microorganisms including Pseudomonas aeruginosa, E. coli, Staphylococcus aureus, Giardia and Cryptosporidium parvum (Crypto), can cause serious illness in swimmers – Chloramines can cause breathing disorder illnesses sometimes called “Swimmers Asthma” 5
  6. 6. Model Aquatic Health Code (MAHC)• Currently there is no uniform national standard for water quality or RWI response• To address this, the CDC has developed a Model Aquatic Health Code (MAHC)• State and Federal public health officials along with industry professionals from across the US, have participated for five years in the creation of the MAHC’s twelve modules which include the best available standards and practices for protecting public health• The MAHC is formatted to be easily adopted by state and local health departments• The CDC states it is “intended to transform the typical health department program into a data-driven, knowledge-based, risk reduction effort to prevent disease and injuries and promote healthy recreational water experiences” 6
  7. 7. MAHC Disinfection & Water Quality ModuleThe Disinfection and Water Quality Module contains requirements for new or modified construction that include:• Primary disinfectant levels set• Secondary disinfection required for “increased risk” aquatic venues such as interactive features, spray pads, wading pools, and other venues designed primarily for diaper-aged children as well as therapy pools• Combined chlorine maximum levels set• Prohibition of cyanuric acid in Indoor facilities and “increased risk” aquatic venues 7
  8. 8. Secondary Disinfection Systems SDSs• When the MAHC is published in spring of 2013, it will include a section on the importance of Secondary Disinfections Systems (SDSs) to significantly reduce RWIs (caused by microorganisms and chloramines)• According to the MAHC – All Secondary Disinfection Systems (SDSs) must be certified to NSF/ANSI Standard 50 by an ANSI-Accredited third-party testing and certification organization to verify that they provide the minimum inactivation of Cryptosporidium parvum in the full flow – All Secondary Disinfection Systems (SDSs) must provide a minimum of 3 log (99.9%) inactivation of Cryptosporidium parvum in the full flow, prior to return of the water to the pool or aquatic feature at the minimum turnover rate• Approved SDSs are Ozone systems and UV systems 8
  9. 9. MAHC Disinfection & Water Quality SDS Aquatic VenuesThe new construction or substantial renovation of the following INCREASED RISK AQUATIC VENUES shall be required to use a SECONDARY DISINFECTION SYSTEM after adoption of this CODE:1) AQUATIC VENUES designed primarily for diaper-aged children (children <5 years old), such as a. wading POOLS, b. water activity POOLS, c. interactive water features with no standing water, d. SPRAY PADs, and2) Therapy poolsOptional SECONDARY DISINFECTION SYSTEMS may be installed on all other aquatic venues not specified above to provide the same quality of protection to bathers 9
  10. 10. Definitions of Ozone and UV• Ozone is a gas that is dissolved in water to kill microorganisms, destroy organics, and break down chloramines by oxidation. This occurs immediately at the ozone gas injection point, and continues as the side-stream remixes with the main return. A small residual (~0.1 PPM) of dissolved ozone will enter the pool, providing further oxidation of contaminants.• UV light inactivates microorganisms and breaks down chloramines with light energy. This happens while the water is in the UV chamber only, and as long as the water has no turbidity. No further process occurs once the flow leaves the chamber. UV provides no oxidation except as trace amounts as a result of the formation of a limited number of hydroxyl free radicals in or near the UV chamber. 10
  11. 11. Properties of Ozone• Ozone (O3) is a gas derived from oxygen which can be readily dissolved in water• Ozone has a fresh scent at low concentrations and smells pungent at higher concentrations• Gaseous Ozone dissolved in water is referred to as Aqueous Ozone (which has no odor)• Ozone is a powerful antimicrobial oxidizer and sanitizer• Aqueous Ozone is an effective micro-flocculant• Aqueous Ozone is an effective anti-foaming agent• Aqueous Ozone is an effective antimicrobial agent• The disinfecting capability of 1 PPM Aqueous Ozone is equivalent to many times (10 to 4,000 times) the concentration of free available chlorine (Morris, 1975 – Disinfection: Water & Wastewater), depending on pH, temperature, and on the specific microorganisms to be destroyed• Ozone is compatible with Chlorine in Swimming Pools 11
  12. 12. Benefits of Ozone• Ozone controls the chloramine levels in the water on average to 0.2 PPM or less• Ozone can eliminate “shock-oxidizing” for chloramine reduction• Ozone offers significantly more oxidation than free available chlorine (FAC) alone• Ozone provides a minimum 3 log (99.9 percent) kill of Cryptosporidium parvum and other RWI pathogens in a side-stream applied single-pass• Ozone will destroy emerging pharmaceutical pollutants such as endocrine disruptors• Ozone provides micro-flocculation to aid filtration and noticeably improve water clarity (eliminates foam from spas)• Ozone destroys biofilm• Chlorine consumption is reduced by 50-75% while still maintaining an FAC residual; at the lowest applied O3 dose of 1.6 PPM 12
  13. 13. Can Ozone Stand Alone?• Ozone’s role is actually as the primary sanitizer, and ozone disinfection will pass into the pool, but maintaining an ozone residual in the pool that is high enough to ensure continuous in-pool protection from bather-to-bather cross-contamination can be expensive; and present the risk of ozone off-gas• With current technology it’s impractical to expect ozone to perform as a stand-alone sanitizer in a public swimming venue without a residual halogen in the pool (0.3-1.0 PPM)• A low residual of chlorine, in conjunction with an appropriately sized and maintained ozone system, will be virtually undetectable even by the most sensitive bathers, and keep operating costs very low 13
  14. 14. How is Ozone Measured?• Dissolved ozone is measured by an Oxidation Reduction Potential (ORP) monitor/controller in a swimming pool• The ORP reading can range between 600 mV to 900 mV at the point of introduction into the main return line before entering the pool• An ORP of 800 mV is ~ 0.2 PPM dissolved ozone which is estimated to equate to ~40 PPM Cl in terms of oxidation and antimicrobial efficacy 14
  15. 15. Breakdown of Pool Types Based on bather load and water temperature, four categories are identified1. Recreation/Lap Pool (78-85°F)2. Therapy/Swim School Pool (86-94°F)3. Wading Pool/Spray Pad (80-88 °F)4. Spa (94-104°F) 15
  16. 16. Ozone Sizing Parameters• In each of the 4 categories, 1.6 PPM Ozone is applied to the total volume of the pool based on time, using a conversion constant of 0.227• The time value changes with each category (the higher the temperature and bather load, the more ozone is required)1. Recreation/Lap Pool 1.6PPM/24 hr (1440 min)2. Therapy/Swim School Pool 1.6PPM/12 hr (720 min)3. Wading Pool/Spray Pad 1.6PPM/4 hr (240 min)4. Spa 1.6PPM/2 hr (120 min) 16
  17. 17. Ozone Retention Parameters• Ozone is measured by the combination of applied Ozone Dose and Retention Time in the side stream (CT Value [Concentration X Time])• Retention time for all pool types is a minimum of one minute, measured immediately at the injector outlet in the sidestream, inclusive of the volume of the degas tank, volume of the sidestream plumbing and the volume of the mainstream plumbing just prior to the halogen feed location and before entering the pool 17
  18. 18. Sample Pool Ozone Sizing• Pool Example – 100,000 Gallon Recreation/Lap Pool • Ozone dose is 1.6 PPM (D) – Volume/Minutes = Ozone Dose Flow (F) • 100,000/1440 = 69 GPM (F) – Generator Sizing Formula: D * F * 0.227 = Grams per hour Ozone Required • 100,000/1440 * 1.6 * 0.227 = 25 grams/hour – Retention Tank Sizing Formula: F * T (minutes) = Size of Retention in Gallons • 69 * 1 = 69 gallons 18
  19. 19. Ozone Regulatory1976 EPA Approves Ozone as an Antimicrobial Oxidizer Device1982 IBWA Bottled Water Association Approve Ozone as an Antimicrobial for Product, and Disinfectant for Filler Lines1999 EPA Lists Ozone as Safe for Surface and Ground Water2001 FDA/USDA Approve Ozone as an Antimicrobial Food Additive2001 FDA/USDA Approve Ozone as a Food Contact Surface Disinfectant2001 USDA National Organic Program Allows Ozone as an Antimicrobial Food Additive and Food Surface Disinfectant2010 Ozone is added to the FDA Model Food Code as an approved antimicrobial surface sanitizer2012 Ozone is recommended as a Secondary Disinfection 19 System in the Model Aquatic Health Code
  20. 20. Ozone SafetyEPA approved• As a pesticide, ozone equipment must be registered by the EPA under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). DEL Ozone is an EPA registered establishment (EPA Estab. No. 071472-CA-001).OSHA Regulations for Ozone (Gaseous Only)• Health Hazard Data – Inhalation /Respiratory System, Eyes, Blood• PEL (Permissible Exposure Limit) – 8 hour Time Weighted Average 0.1 PPM Vol.• STEL (Short Term Exposure Limit) – 15 Minute 0.3 PPM Vol.• IDLH (Immediately Dangerous to Life and Health) – 5 PPMNo OSHA Regulations apply to Aqueous Ozone; it is not harmful to humans 20
  21. 21. Ozone safety• Vacuum Generated Ozone Ensures User Safety – No ozone gas can escape in the event of loss of vacuum – Systems provide complete isolation in the event of any shutdown• Vacuum Operation Optimizes Mass-transfer Efficiency – Venturi Injectors operate under negative pressure; a vacuum ozone system provides ease of injector adjustment and operation – Mass-transfer is optimized and consistent – Optimized mass-transfer results in more dissolved ozone – Undissolved ozone is degassed and destroyed 21
  22. 22. Definition of Sanitizers &DisinfectantsA Sanitizer is one of the three groups of antimicrobialagents registered by the USEPA for public healthuses.Disinfectants are antimicrobial agents that are appliedto non-living objects to destroy microorganisms, theprocess of which is known as disinfection.Sanitizers are substances that reduce the number ofmicroorganisms to a safe level.The main difference between a sanitizer and adisinfectant is that at a specified use dilution, thedisinfectant must have a higher kill capability forpathogenic bacteria compared to that of a sanitizer.
  23. 23. Ozone is an EPA ApprovedAntimicrobial, Disinfectant &Sanitizer by all DefinitionsOzone Performs theseFunctions as an OxidizerIn Use for over a CenturyWorldwide as a WaterDisinfectant
  24. 24. Ozone Biocidal BehaviorElectron Micrographs of E. coli before/after ozone treatment E. coli dried as a biofilm on a porous surface Before ozone treatment After ozone treatment Electron Magnification Scale of Measure Working Distance Sequential Beam Power One Micrometer (micron) 1. Ozone oxidizes cell membranes, causing osmotic bursting (instantaneously) 2. Ozone continues to oxidize enzymes and DNA 24
  25. 25. Public Bath Tubs Ozone Anti-Microbial Validation under ANSI/NSF Protocol P308Pass compliance requires a 3-log (99.9%) reduction of E. coli, Staphylococcusaureus, Pseudomonas aeruginosa, Trichophyton mentagrophytes and Candidaalbicans in 30 minutes Actual Microbial Reductions in 30 Minutes E. coli 4.7 log (>99.99%) Staphylococcus aureus 4.7 log (>99.99%) Pseudomonas aeruginosa 3.2 log (>99.9%) Trichophyton mentagrophytes 4.0 log (99.99%) Candida albicans 4.7 log (>99.99%)Test Parameters• Water temperature @ 93° F• 20 PPM oil insult• 1.1 PPM side-stream applied ozone dose Low Dose Ozone• Microorganism destruction was measured in the tub 25
  26. 26. Public Swimming Venues Ozone Anti-Microbial Validation under ANSI/NSF Standard 50, Annex HPass compliance requires a 3-log (99.9%) reduction of Pseudomonasaeruginosa and Enterococcus faecium in 30 minutes Actual Microbial Reductions in 6 Minutes Pseudomonas aeruginosa 6.6 log (>99.9999%) Enterococcus faecium 6.7 log (>99.9999%)Test Parameters• Water temperature @70° F• 20 PPM oil insult• 9 PPM Urea insult• 1.6 PPM side-stream applied ozone dose• Microorganism destruction was measured in the pool 26
  27. 27. Public Swimming VenuesOzone Antimicrobial Validation for Cryptosporidium parvum Reduction testedby NSF InternationalPass compliance requires a 3 Log (99.9%) reduction of Cryptosporidium parvum Actual Microbial Reductions in 30 Seconds Cryptosporidium parvum 3.0 log (>99.9%)Test Parameters• Water temperature @76° F• 1.6 PPM side-stream applied ozone dose• Crypto measurements were taken on a single pass [measured after side-stream is diluted in full flow] 27
  28. 28. Side-Stream AppliedSingle Pass 28
  29. 29. CT Values for Cryptosporidium parvum InactivationCT Value Concentration times Time (PPM * Minutes Exposure = CT Value)Chlorine CT is 15,300 [20 PPM for 13 hours (780 minutes)]Aqueous Ozone CT is 0.72 (1.257 PPM for 34 seconds)
  30. 30. How Ozone is Made• Oxygen molecules (O2) split by adding energy, resulting in two individual oxygen atoms (O1)• Oxygen atoms (O1) unite with other oxygen molecules (O2) to produce Ozone (O3)• (O1) + (O2) = (O3) 30
  31. 31. How Ozone Works• The third oxygen atom is held by a weak single bond• An oxidation reaction occurs upon any collision between an ozone molecule and a molecule of an Oxidizable substance• The weak bond splits off leaving oxygen as a by-product• During an oxidation reaction, organic molecules are changed or destroyed and dissolved metals are no longer soluble 31
  32. 32. MAHC Ozone System RequirementsAn ozone system shall be a complete system consisting of the following (either skid-mounted or components):1) Ozone generator2) Injector / injector manifold3) Reaction tank (contact tank) / mixing tank / degas tower4) Degas valve (if applicable, to vent undissolved gaseous ozone)5) Ozone destruct (to destroy undissolved gaseous ozone)6) ORP monitor / controller7) Ambient ozone monitor / controller8) Air flow meter / controller9) Water backflow prevention device in gas delivery system 32
  33. 33. Basic Ozone System 33
  34. 34. Very Small Ozone System 34
  35. 35. Small Ozone System 35
  36. 36. Large Ozone System 36
  37. 37. Ozone Generation System Components 37
  38. 38. Ozone Gas Dissolution 38
  39. 39. Ozone Reaction in Water 39
  40. 40. Degas Undissolved Ozone 40
  41. 41. Destroy Undissolved Ozone 41
  42. 42. Flange to Flange Ozone Skid 42
  43. 43. Ozone Systems Made Simple• Complex ozone systems of the past have been replaced by modern, compact, affordable systems• Skid-mounted, plug and play ozone systems are the norm for 100,000 gallon pools and smaller• Flange to flange hook-up to the main return line decreases cost and complexity of the installation• The system’s 4’X3’ footprint is compact to easily fit into the equipment room 43
  44. 44. Costs and Savings with OzoneAssumptions• 100,000 gallon indoor pool• $250/ 10 PPM shock/100K Gal (chlorine @ $2.50/gal)• Shock (without ozone) estimate 52 per year = $13,000• Annual chlorine use estimate is based on chlorine cost @ $2.50/galBather load assumptions• 100 bathers/day = 1,825 gals @ $2.50 = ~$4,563• 200 bathers/day = 3,650 gals @ $2.50 = ~$9,125• 300 bathers/day = 5,475 gals @ $2.50 = ~$13,687• 400 bathers/day = 7,300 gals @ $2.50 = ~$18,250• Chlorine reduction with ozone is average 50%Ozone System Cost Estimates• End-user purchase price $30,000.00• Annual power consumption at 0.12 per kWh $2,375.00• Annual Maintenance parts $300.00Savings Estimates• Eliminate shock treatments and labor costs $13,000 plus labor cost savings• Chlorine Reduction at 50% avg. 100 bathers/day $2,281 400 bathers/day $9,125 savingsReturn on Investment (ROI) approximately 1.5 - 2 years 44
  45. 45. Ozone Compatibility with Cl and Br • Ozone’s reaction with chlorine is minimal • Ozone will break down chloramines • Ozone provides the main oxidation and disinfection in the pool while the chlorine provides a chemical residual • Ideal Chlorine residual is 0.3 – 1.0 PPM • It is not recommended that ozone be used in conjunction with bromine. When used with bromine, ozone oxidizes “spent” bromine (bromide) back to useful bromine. This depletes the ozone before it can oxidize the organic contaminants in the water, and significantly reduces ozone’s efficacy. 45
  46. 46. Ozone compared to UVSterilizersBoth Ozone and UV provide very effective Crypto reduction as documented by NSF Standard 50, Annex HOzone Destruction of Chloramines• Ozone breaks down Chloramines by oxidation in two ways – By breaking down the N-Cl bonds of the Chloramine molecules through oxidation by ozone (this process occurs at the point of ozone injection and continues the oxidation process as it passes at low levels into the pool) – Ozone also forms hydroxyl free radicals, adding to the Chloramine oxidation process• Ozone reduction of Chloramines is also a function of its powerful oxidation of chloramine-producing organic contaminants; eliminating their initial productionUV Destruction of Chloramines• UV can break down Chloramines in two ways – By breaking the N-Cl bonds of the Chloramine molecules with UV light energy (this process occurs in the UV chamber only) – By forming small numbers of hydroxyl radicals with UV light energy, which oxidize Chloramines (this process occurs within nanoseconds, effectively occurring only in, or very near the UV chamber)• UV produces very little oxidation to affect organics in the water 46
  47. 47. Ozone and UV comparison OZONE UV Ozone kills cryptosporidium parvum  UV inactivates cryptosporidium parvum Ozone kills microorganisms  UV inactivates microorganisms Ozone is a powerful oxidizer UV is not an oxidizer Ozone passes into the pool at low levels to provide UV affects the water only as it passes through the UVadditional oxidation chamber Ozone functions well in cloudy water, and is a Only clear water can be effectively dosed with UV;micro-flocculent, which aids water clarification cloudiness in the water can absorb the UV light Ozone oxidizes the organics and inorganics that UV breaks down chloramines that have been previouslycreate chloramines, eliminating their production created Ozone utilizes ORP (REDOX) to measure the UV systems utilize a UV intensity meter whichcleanliness of the water measures the UV dose regardless of water quality Ozone’s reaction with free available chlorine (FAC)  UV can break down free available chlorine in theis very slow and in a pool will not affect the FAC water while it breaks down chloramineslevels; only chloramine destruction Mercury vapor lamps are replaced @ 3-12 mos.; Ozone cells require no replacement; require annual disposal procedures must be considered as lamp gasesperiodic cleaning; no hazardous components are considered hazardous waste Ozone destroys biofilm UV does not affect biofilm Ozone destroys Humic and Fulvic Acid UV does not affect Humic and Fulvic Acid 47
  48. 48. Ozone and UV Together• Ozone and UV may be used together to create a synergistic approach to water sanitation• This process has been in use for drinking water, food processing, and waste water for many years• It is one of several advanced oxidation processes (AOPs) that are in commercial use today in selected industrial processing• The technology has rarely been used in public pools to date, but with the advent of improved technology and cost reduction, perhaps it will be the wave of the future for RWIs and chloramine elimination 48
  49. 49. Indoor Swimming Venues KEY LIME COVE INDOOR WATERPARK, Gurnee, IL 49
  50. 50. Outdoor Swimming Venues Atlantis Resort, Paradise Island, Bahamas Outdoor Lagoon Pool 50
  51. 51. Conclusion• Advances in Ozone Technology have provided the means for affordable and effective ozone systems• Commercial Swimming Venues benefit from safer, cleaner and more manageable water, free of chloramines and noticeably clearer 51
  52. 52. References and Credentials• INTERNATIONAL OZONE ASSOCIATION PROCEEDINGS OF THE INTERNATIONAL OZONE ASSOCIATION - PAN AMERICAN GROUP ANNUAL CONFERENCE, September 19-22, 2010, Bellevue, Washington – Peer reviewed and Copyrighted © 2010• DISINFECTION AND WATER QUALITY TECHNICAL COMMITTEE - MODEL AQUATIC HEALTH CODE – Peer reviewed 2010• RIP G. RICE, PH.D., R.I.C.E. INTERNATIONAL GLOBAL OZONE CONSULTANT – Peer reviewed 2010• HAAG, W. R. AND HOIGNE, J.(1984) Kinetics and products of the Reactions of Ozone with Various forms of Chlorine and Bromine in Water, Ozone: Science & Engineering, 6: 2, 103 - 114• AIR LIQUIDE AMERICA CORP, Chicago Research Center, James T.C. YUAN, Ph.D., ca 2000• NSF INTERNATIONAL ANSI/NSF Protocol P308 - Validation• NSF INTERNATIONAL ANSI/NSF Standard 50 - Validation• NSF INTERNATIONAL ANSI/NSF Standard 50 – Annex H (Microbial Efficacy and Ozone Safety) – Validation• NSF INTERNATIONAL Report J-00047649 (Cryptosporidium parvum) - Validation• NSF INTERNATIONAL TOXICOLOGY GROUP safety testing based on Hazard Communications Standard as promulgated through the Occupational Safety and Health Act (OSHA) of 1970 and documented in the Code of Federal Regulations, Title 29 – Compliant• USEPA registered establishment under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) - Compliant• USEPA/FIFRA Office of Pesticide Programs (OPP) Disinfectant Technical Science Section (DIS/TSS) - Compliant
  53. 53. Beth HamilVice PresidentCorporate ComplianceDEL Ozone800 676 1335 ex. 222805 441 4444beth@delozone.comOzone liaison for: Water Quality Technical Committee of the MAHC APSP Recreational Water Quality Committee ANSI/NSF Standard 50 Joint Committee FDA Food Code State Health Department Consultant for ozone applications 53