Presentation is loading. Please wait.

Presentation is loading. Please wait.

Legionella Risk Management

Similar presentations


Presentation on theme: "Legionella Risk Management"— Presentation transcript:

1 Legionella Risk Management
The goal of this presentation is to: Educate and provide a more thorough understanding of the Legionella bacteria including the ecology and morphology of the bacteria as it pertains to industrial water-handling systems. Introduce and define Drew Industrial’s Best Practices Legionella risk management program. Drew Industrial Division Ashland Canada Corp

2 Legionnaires’ Disease
A potentially fatal form of pneumonia caused by the inhalation of airborne water droplets contaminated by Legionella pneumophila and other bacteria of the family Legionellaceae Legionnaires’ disease is a severe form of Legionellosis that can cause serious complications and possibly death. The disease is caused by inhaling airborne droplets or mist containing viable Legionella pneumophila which are small enough to pass deep into the lungs. The organism then becomes deposited in the alveoli, the small pockets in the lungs. Ingesting Legionella pneumophila has not been shown to cause disease.

3 Facts About Legionnaires’ Disease USA
First cases in 1976 at Bellevue Stratford Hotel, PA; 221 people contracted LD, 34 died Severe respiratory infection simulating pneumonia An estimated 10,000 to 50,000 cases per year An estimated 1 percent of those exposed contract Legionnaires’ disease Estimated fatality rate is percent Although Legionella is not a new organism, it was first recognized in 1976 at the American Legion Convention in Philadelphia when 221 people contracted the disease and 34 died. Legionnaires’ disease is often misdiagnosed because symptoms closely resemble pneumonia. CDC estimates that between 10,000 and 50,000 cases occur every year; however, that number is probably much higher due to high incidence of misdiagnosis. Most people have antibodies to Legionella. Of those exposed to Legionella, an estimated 1% contract disease. Of that 1%, the fatality rate is 15-20%, but in immunosuppressed individuals or those with chronic illnesses, that number can be much higher.

4 Legionella Regulations
Legionella legislation in Australia, NZ and UK forces customers to treat properly: Prosecution and fines for noncompliance Can shut down the system Legionella risk management is not regulated in the United States. While many professional organizations, such as Cooling Technology Institute (CTI) and American Society of Heating, Refrigeration and Air Conditioning Engineers, Inc. (ASHRAE), have issued guidelines, none are governed by law or regulation. CDC’s (Center for Disease Control and Prevention) position is that time and money are best spent on controlling biofilm. Other countries, such as those noted, do have legislation that mandate specific risk management protocol. If protocol is not followed, there are enforcement and other consequences.

5 Legionellosis Compared to Pontiac Fever
Legionnaires Disease Pontiac Fever First Noted 1976 1968 Form Bacteria Virus Attack Rate 1 – 5 Percent 95 Percent Symptoms Fever, Cough, Muscle Aches, Chills, Headache, Chest Pain , Sputum, Diarrhea, Confusion Fever, Cough, Muscle Aches, Chills, Headache, Chest Pain, Confusion Effects on Lung Pneumonia, Pleural Effusion Pleuritis, No Pneumonia Other Affected Organ Systems Kidney, Liver, Gastrointestinal Tract, Nervous System NONE Case-Fatality Ratio 15 – 20 Percent No Fatalities

6 Susceptability to Legionnaires’ Disease
Age – The very young and 40 – 70 year olds Gender – Males are twice as likely to contract the disease than females Heavy Smoker Heavy Drinker Individuals with weakend immune systems – Cancer, AIDS, HIV positive Chronic Medical Problems – respiratory, diabetes, asthma, renal dialysis Certain Drug Therapies – corticasteroids or other immunosuppressive therapies Organ Transplants

7 Legionella Rod-shaped, aerobic organisms
Found in natural and man-made water systems Up to 40 species identified Legionella pneumophila Virulent strain causing Legionellosis Legionella are gram-negative, rod-shaped, aerobic organisms commonly found in both natural and man-made water systems. Although Legionella are aerobic, the organism can survive in low oxygen environments. Up to 40 species have been identified; however, the Legionella pneumophila species is the one that is associated with human disease. Legionellosis is an infection caused by the inhalation of airborne water droplets containing the Legionella pneumophila bacteria. Legionellosis is more commonly called Legionnaires’ disease, or LD.

8 Factors Determining the Risk of Contracting the Disease
A source of Legionella Favorable growth conditions Aqueous aerosol Sufficient organisms to cause infection Susceptible individual All these conditions must be present in order to contract Legionnaires’ disease. There must be a source for Legionella, and there must be a sufficient amount of the organism to cause infection. Conditions must be optimized to enhance growth (temperature and nutrients). The organism must be transmitted via an aqueous aerosol or mist and inhaled into the lungs in order to contract disease. Although Legionnaires’ disease can occur in healthy individuals, among those at increased risk include smokers, those with chronic respiratory diseases, cancer, immunosuppressed conditions, and other chronic illnesses.

9 Legionella Bacteria Source of Legionella Conditions for growth
Pervasive organism Conditions for growth 68 - 122 F (20 - 50 C) pH 6-8 Stagnant waters A nutrient source Biofilms, organics Sediments, deposits Ecology and morphology of the Legionella organism: The organism is found in all water sources including rivers, streams, lakes, mud and soil samples, water and sludge from cooling systems and other man-made water-handling systems. Optimum conditions for growth include: temperatures between 68F-122 F. The bacteria are killed at 140F and can remain dormant below 68F pH 6-8 Stagnant water contributes to the potential for Legionella because the lack of circulation encourages growth Nutrient sources such as those mentioned provide “food” for the organism

10 Legionnella Bacteria Soil Derived
Spore Former ,Facultative Anaerobe (Maturing Biofilm) Iron and Amino Acids are Food Sources “CDC” Legionella Pnemophila 90% of All Outbreaks 82% are from Serogroup 1 Others from Serogroup 4 and 6 Outbreak Potential at ≥ 1000 CFU/ML

11 Legionella belongs to a special group of bacterial pathogens that invade host cells and exhibit parasitic properties. Legionella can survive and grow within host organisms such as protozoa and amoeba. Photographs have been taken of amoeba engulfing and harboring Legionella bacteria.

12 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 All systems noted are at a potential risk for transmitting Legionella bacteria because they have the potential to meet all the criteria noted in slide # 5, i.e., A source of Legionella organism Optimum conditions for growth Aqueous aerosol for transmission Sufficient organisms to cause infection Transmission to susceptible individual

13 Hot Water Requirements for Superheating of potable water systems; If the water is heated to at least 149 degrees F. Legionella die rapidly at 131 F and killed immediately at temperatures over 140 F. Water outlets are flushed for at least 30 minutes (Pittsburgh) or 5 min (CDC). It is recommended that the Hot water stored above 140 F circulation with the minimum return of 124 F.

14 Cold Water For cold water, the same as above can be done with heater or shock hyperchlorination ( >10 ppm) of chlorine in water and flush for at least 5 minutes. Additional protocols available and may be required on a local basis.

15 Legionella Testing General consensus is that testing is not effective
Money better spent on biofilm control Many professional organizations provide guidance such as CTI, ASHRAE, etc.

16 The Role of Biofilms The prime culprit
Harbors Legionella and promotes growth Promotes growth of higher life forms such as Protozoa and Amoeba - act as a protective host Reversible adsorption of bacteria (sec.) Irreversible attachment of bacteria (sec.-min.) Growth & division of bacteria (hrs.-days) Exopolymer production & biofilm formation (hrs.-days) Attachment of other organisms to biofilm (days-months) Surface Sessile Planktonic trapped particles providing nutrients embedded bacterial cells Water Flow It is believed that Legionella do not grow within the bulk water but within established biofilms – the slime and sludge that builds up within recirculating water systems, particularly in low flow areas or deadlegs. Research suggests that most of the Legionella found in cooling systems are within biofilms. Biofilms build up rapidly on surfaces within a water system. Within a few hours of exposure, an organic film developed from microbiological activity will build up. Bacteria will attach themselves to the surface by means of extracellular polysaccarides and grow to form micro-colonies. These micro-colonies eventually merge to form a microbial film. This matures as stalked and filamentous bacteria develop and extend further into the bulk water phase. The biofilm entraps inorganic corrosion and scale products and organic debris from other microbial growth, providing both nutrients and bulk. If biofilms provide conditions, nutrients and protection for Legionella bacteria, then monitoring and controlling biofilm formation must become a priority in order to minimize the potential for Legionnaires’ disease.

17 We know that… In order to minimize Legionella growth:
Chemical treatment alone is not effective Minimization is dependent upon design, maintenance, contaminants, awareness and consistent implementation Effective Legionella management requires a “best practices” approach: A system that is properly treated, serviced and supervised Although chemical treatment is important, it is not the only line of defense against Legionella. A comprehensive system approach involving chemical, mechanical and operational practices is the best means of reducing the possibility of exposure to Legionella.

18 Simplified Surface Growth

19 Field Study on Biofilm Growth
Phase Time Colonization 15 Minutes Growth Detection 2 Days Biofilm Formation (Exopolymer/ Minimum Biofouling) 5 Days Maximum Biofilm Growth (8 – 10 Cells Thick) 14 Days Fully Mature Biofilm Matrix 31 – 40 Days

20 Three Dimensional Biofilm

21 Legionella risk minimization depends on the ability to control:
We know that… Legionella risk minimization depends on the ability to control: Growth Dissemination Transmission Risk management depends on controlling three major events: Growth: Controlling the growth and multiplication of organisms. Dissemination: Circulating water systems favor rapid contamination of the system regardless of the source of contamination. Transmission: Legionnaires’ disease is contracted by the inhalation of water droplets containing the Legionella pneumophila organism deep into the lungs via aqueous aerosols or mists.

22 Areas Promoting Growth
Biofilm Algae A cooling tower system can present an ideal environment for growth of Legionella as well as nutrient sources. Some prime examples of potential “food sources” are noted. It is especially important to control the formation of biofilm since biofilms can harbor Legionella and act as a protective host. Biofilm Debris

23 Questions? (Clarify any questions on the morphology and ecology of the Legionella organism and Legionnaires’ disease prior to introducing and defining Drew Industrial’s Best Practices Legionella risk management program.)

24 CTI Protocol Establishes Baseline Program
Legionella Guidelines February, 2000 position paper Background summary and guide Platform for developing a more comprehensive, definitive program Guidelines were based on industry consensus prior to ACOP (UK-Regulated Approved Code of Practice) In February 2000, the CTI published guidelines, the cover shown here, which represent a detailed description of common opinions on best practices for Legionella control from a variety of sources. Representing a good basis for Legionella growth minimization, it also allows for much flexibility and ultimately interpretation by the end user. CTI position paper is an industry-developed consensus for Legionella best practices protocol. However, program implementation is subject to facility interpretation.

25 CTI Protocol Halogen feed is required Testing and monitoring
Continuous halogen with free residual is preferred Use non-oxidizing biocide and/or biodispersant as needed Intermittent halogen with higher levels of free residual is acceptable Non-oxidizing biocide specifically recommended Biodispersant may be required Testing and monitoring Routinely monitor total bacteria using dip slides or agar Maintain less than 10,000 CFU/mLspecifically recommended Routine Legionella testing is not recommended Only after suspected case or following sterilization Sterilization may be required Maintain 5 ppm FAH for 6 hours minimum Specifically recommended based on various system indicators This slide provides a brief summary of the CTI guidelines. The CTI Position Paper is readily available for review and should be read to gain a more thorough understanding of the guidelines. One point clearly noted by CTI is that oxidant feed is required for bacterial growth management. Continuous feed is preferred, but intermittent feed is acceptable. The use of organic biocides is highly recommended for intermittent feed protocols but not clearly defined. Routine total bacteria level testing is recommended. Routine Legionella testing IS NOT recommended. (NOTE: Most professional and government agencies including ASHRAE, Joint Commission, CDC also do not recommend Legionella testing). The reason is that an acceptable threshold level of Legionella has not been established. Also, Legionella may not be detectable in bulk water one day but can repopulate and be present in following days. Detection does not necessarily mean there is a potential for contracting the disease because of the wide array of serogroups within the Legionella family. CTI recommends periodic sterilization without defining “periodic.” CTI also recommends sterilization for specific system upset conditions. CFU is colony-forming units, the measure of viable bacteria in a sample.

26 Drew Industrial’s Best Practices Legionella Risk Management Program
Drew Industrial has expanded on the CTI guidelines and provides recommended action for those subjective areas noted in CTI through its own Best Practices. Drew Industrial’s Best Practices microbiological treatment program is based on over ten years of experience in the UK where we have consistently met stringent government standards. The backbone of the program relies on an intensive microbiological treatment approach which is Drew Industrial’s recommended minimum protocol. This program can be further enhanced with a comprehensive risk management approach which implements a detailed assessment, action plans and record keeping which show that the critical factors have been identified and steps are being taken to mitigate them.

27 Total System Approach: Five Areas of Activity and Performance
 Comprehensive system assessment  Intensive microbiological treatment program  Sterilization and cleaning  Monitoring and control  Documentation Drew Industrial’s Best Practices Legionella risk management program consists of five areas of activity and performance. While these areas are similar to our regular performance-based programs, the emphasis and focus is much more intensive in two areas: controlling microbiological and biofilm growth, and document actions. The five components of the our program are: 1. System assessment - This is a formal process for evaluating the critical factors of an industrial water-handling system in terms of mechanical, operational, environmental, and chemical treatment program. Factors are identified, evaluated, and rated in terms of conditions that can potentially favor Legionella growth and potential for exposure. 2. Intensive microbiological treatment program - Application of a customized, intensive microbiological treatment program specifically designed to control bacteria as well as control Legionella-harboring biofilms. 3. Periodic sterilization - The program focuses on minimizing the biofilm and other deposits that enhance Legionella growth. 4. Monitoring and control - An effective program is dependent on maintaining a consistent level of performance and control through routine monitoring of critical water parameters and system indicators. 5. Documentation - A thorough documentation package provides the necessary records that assure the proper precautionary measures and treatments are being implemented to minimize Legionella.

28 Comprehensive Water System Management
Risk management programs require a comprehensive system approach in order to be effective. While the chemical program is important, it is equally important to maintain the mechanical portion of the system. This slide shows many of the operational, mechanical, treatment and system management aspects of a comprehensive system approach.

29  System Assessment System survey
In-depth survey of system mechanical design and operating conditions Utilizes established protocol, ex BSRIA- Building Services Research Institute Assoc. (UK) Identify, evaluate and rank specific factors associated with potential for microbiological growth and Legionella Mechanical and chemical Determine risk minimization action plans A formal system assessment is the first component of our Best Practices program and is an essential activity for Legionella risk management. The system assessment is a “fee for service” survey that fully reviews mechanical, environmental, operational, and chemical treatment program parameters and evaluates the factors associated with the potential for microbiological growth and Legionella. The system survey evaluates the entire system in terms of critical factors and identifies mechanical and operational practices that should be modified to enhance system cleanliness. The system survey follows an established, detailed protocol that is based on our decades of experiences in England (UK), using their regulated Approved Code of Practices (ACOP) guidelinesn and Australia and New Zealand where risk management is mandatory and regulated. In addition to global experiences, Drew Industrial’s Legionella risk management program is based on recommendations by CTI, ASHRAE, CDC, OSHA, and others. The outcome of this assessment is a plan to minimize overall microbiological growth, minimize aerosol production and distribution from water systems, and recommendations to improve overall system cleanliness. Implementing the plan reduces the opportunity for Legionella growth and spread. Drew Industrial can perform system assessments using trained internal resources or can use outside experts to perform these surveys and risk assessments. (Contact Joanne Kuchinski in Boonton for more information.)

30 Survey Provides Plan to Reduce Growth
1. Address non-chemical ways to improve microbiological control Remove piping dead legs Revise operating procedures Rotate idle equipment Use side stream filtration 2. Identify operating procedures, mechanical design and other factors that contribute to growth of Legionella The system assessment may identify mechanical improvements to minimize stagnant conditions, improve system cleanliness, or suggest the use of filters and other ways to remove mud and suspended debris, as well as improve routine operating practices. For example, rotating idled recirculating pumps and equipment on a routine basis may reduce the number of stagnant water locations in the system, thereby reducing the prospect of biofilm formation.

31 Identify areas that promote growth or dissemmination of Legionella
The initial goal of a system assessment is to identify those areas of a system that promote growth or dissemination of Legionella. Identification does not mean that the condition being noted will cause growth of Legionella or Legionnaires’ disease, but does mean the situation represents a potential source for enhancing bacterial growth and biofilm. Four examples identified in a system survey are shown here. Upper left: Photo of damaged drift eliminators. Potential for escape of aerosols. Upper right: Broken screen which allows for the introduction of birds and other matter that can provide a nutrient source. Lower left: Maintain general cleanliness especially where aerosols are present. Lower right: Broken gutter allows water to be misdirected and represents a potential for aerosol as well as a stagnant pool.

32 Critical Factors Stagnant conditions
Nutrients and conditions for growth Water and chemical treatment quality Water system mechanical conditions Location and exposure risk Five major factors are addressed in the system assessment: Stagnant water conditions: The lack of circulation encourages rapid growth of bacteria. Evaluated in this category are the presence of dead legs, the mode of operation, seasonal and/or intermittent usage and the presence of stagnant water. Nutrients: Nutrients, contaminants and other food sources enhance bacterial growth and multiplication. The presence of organics, slime, sludge and biofilm; water temperature and direct sunlight contact are considered in the evaluation. Water quality: Poor water quality has a direct effect on the likelihood of Legionella and Legionella-harboring organisms to multiply in a system. Factors evaluated in this category include: treatment program, microbiocide program, characteristics of makeup, water parameters, etc. Mechanical system: Design, maintenance and operating performance can have an impact on potential for Legionella transmission. Factors evaluated in this category include the presence of aerosols and measures taken to minimize them (such as drift eliminators) and maintenance of parts/components, Location: Location presents not only the potential for aerosol dispersion but also is an important factor in judging the likelihood of impact to the system by the surrounding environment.

33 “Ideal System” Water flow is continuous
No dead legs or stagnant conditions Basin and deck protected from sun No evidence of sludge, debris, algae Drift eliminators installed, functioning No evidence of aerosols, drift System not near health care, aged, residential facility Low number of people potentially exposed Halogen used Biodispersant/bio-dispersing biocide used Comprehensive water treatment program Automated biocide and chemical dosing Continuous automated monitoring, control This slide summarizes ideal situations yielding the lowest potential for growth and exposure.

34  Intensive Microbiological Treatment Program
Drew Industrial’s Best Practices Legionella risk management program requires an effective system approach that incorporates an intensive microbiological control program along with additional risk management actions As stated, an effective Legionella program is dependent on a comprehensive system approach. The second component of Drew Industrial’s Best Practices program focuses on microbiological control. Typically, most systems already have a performance-based microbiological treatment program in place. However, a pathogen-based, growth minimization program requires a more intensive approach to microbiological control.

35 Intensive Microbiological Treatment Program
Cooling Technology Institute (CTI) position paper Basic program approach Drew Industrial’s recommended intensive microbiological treatment program Comprehensive treatment program incorporating the CTI-recommended actions plus several additional practices CTI guidelines represent a basic management program. Drew Industrial’s intensive microbiological treatment program for Legionella growth management includes all of the CTI recommendations as well as additional practices that are known to promote system cleanliness.

36 Intensive Microbiological Treatment Program
Drew Industrial’s program recommendations for minimizing the potential for growth of Legionella bacteria in cooling systems A comprehensive microbiological control program Includes all recommended CTI actions Includes CTI optional recommendations Provides more definitive guidelines Four protocols based on halogen feed (The four protocols, based on halogen feed schemes, are defined in the next few slides.)

37 Continuous Oxidant Feed Protocol
Continuous feed for chlorine, bromine, BCDMH or stabilized bromine Dosage: Recommended FAH and/or equivalent mV ORP with a minimum requirement of a measurable residual FAH For higher risk systems increase FAH residual as needed to control CFU level and biofilm Feed a supplemental organic biocide* Recommend biocide be glutaraldehyde or an alternate biocide fed with biodispersant Feed once per week or as needed to control biofilm This slide highlights biocide requirements when continuous oxidant feed option is applied. Glutaraldehyde is recommended due to its excellent ability to strip biofilm as well as compatibility with oxidizing microbiocides. In the event glutaraldehyde can not be applied at a facility, alternative organic biocides can be applied. Selection is dependent on Relative Population Density (RPD) study results. ORP is oxidation-reduction potential, the measure of a water’s oxidation energy. *Alternative choices of non-oxidizing biocide should be based on toxicant evaluations (RPD)

38 Total System Approach: Five Areas of Activity and Performance
 Comprehensive system assessment  Intensive microbiological treatment program  Sterilization and cleaning  Monitoring and control  Documentation Drew Industrial’s Best Practices Legionella risk management program consists of five areas of activity and performance. While these areas are similar to our regular performance-based programs, the emphasis and focus is much more intensive in two areas: controlling microbiological and biofilm growth, and document actions. The five components of the our program are: 1. System assessment - This is a formal process for evaluating the critical factors of an industrial water-handling system in terms of mechanical, operational, environmental, and chemical treatment program. Factors are identified, evaluated, and rated in terms of conditions that can potentially favor Legionella growth and potential for exposure. 2. Intensive microbiological treatment program - Application of a customized, intensive microbiological treatment program specifically designed to control bacteria as well as control Legionella-harboring biofilms. 3. Periodic sterilization - The program focuses on minimizing the biofilm and other deposits that enhance Legionella growth. 4. Monitoring and control - An effective program is dependent on maintaining a consistent level of performance and control through routine monitoring of critical water parameters and system indicators. 5. Documentation - A thorough documentation package provides the necessary records that assure the proper precautionary measures and treatments are being implemented to minimize Legionella.

39  Intermittent Oxidant Feed Protocol
Chlorine, bromine, BCDMH or stabilized bromine Minimum dosage: Hold FAH and/or equivalent mV ORP for a minimum of 2 hours each day Feed alternating supplemental organic biocides* Recommend one biocide be glutaraldehyde or an alternate biocide fed with biodispersant Feed an additional compatible organic biocide* Alternate feed once per week This slide highlights biocide requirements when intermittent oxidant feed option is applied. Note the requirement for supplementing the program with two non-oxidizing biocides. * Dosages and alternative choices of non-oxidizers should be based on RPD results

40 Chlorine Dioxide - A Selective Oxidant -
Oxidation potential not affected by pH Selective oxidant No dissociation; does not react with water Does not react with amines, nitrogen compounds Highly effective against biofilm Chlorine dioxide has unique advantages over conventional chlorine and bromine oxidant programs. As a result, continuous and intermittent chlorine dioxide feed protocols are featured separate from the standard continuous/intermittent oxidant feed protocols. Drew Industrial has extensive experience and expertise in this area and is an industry leader in applying and automating this chemistry.

41 Continuous Chlorine Dioxide Feed Protocol
Minimum dosage: 0.1 ppm residual ClO2 or equivalent mV ORP Feed a supplemental organic biocide as needed based on biofilm control Recommend biocide is glutaraldehyde or an alternate biocide fed with biodispersant* Feed once per week or as needed to control biofilm This slide highlights biocide requirements when continuous chlorine dioxide feed option is applied. *Alternative choices of non-oxidizing biocide should be based on RPD results

42 Intermittent Chlorine Dioxide Feed Protocol
Minimum dosage: 0.5 ppm residual ClO2 and/or equivalent mV ORP for a minimum of 2 hours per day Feed alternating supplemental organic biocides* Recommend one biocide be glutaraldehyde or an alternate biocide fed with biodispersant Feed an additional compatible organic biocide* Alternate feed once per week Chlorine dioxide is also an effective supplemental biocide for process cooling systems where contaminants that increase bacterial growth are present. This slide highlights biocide requirements when intermittent chlorine dioxide feed option is applied. Note the fact that chlorine dioxide is an effective supplemental biocide for those systems where bacteriological activity is difficult to control. *Alternative choices of non-oxidizing biocide should be based on RPD results

43  Sterilization Drew Industrial’s Best Practices program recommendation includes annual sterilization regardless of overall system indicators Procedure is per the CTI protocol Annual on-line system hyperhalogenation Maintain 5 ppm FAH for 6 hours minimum, per the CTI process Annual full system cleaning highly recommended Perform six months following hyperhalogenation If an off-line cleaning can not be performed, clean as possible on-line and follow with a second hyper-halogenation The third component of Drew Industrial’s Best Practices risk management program is sterilization, which is essential in maintaining the appropriate degree of system cleanliness for Legionella growth minimization. Periodic system sterilization aids both in eliminating or minimizing biofilm formation and cleaning the overall system. CTI also recognizes the importance of a sterilization program and recommends that on-line hyperhalogenation be performed periodically. Drew Industrial’s Best Practice further defines “periodic” by recommending an on-line sterilization be performed a minimum of once per year. Regardless of schedule, disinfection should occur in the event of certain system conditions such as process leaks, heavy biofouling, regular bacteria counts >105 CFU/mL, stagnant waters, Legionella counts >100 CFU/mL. The CTI protocol recommends a minimum 5 ppm FAH for 6 or more hours, depending on the severity of the system operation, contaminant level from process or environmental sources, etc. In addition, an off-line system cleaning is recommended at least once per year and preferably six months after the on-line hyperhalogenation. If system shutdown is impractical, a second on-line hyperhalogenation should be performed.

44  Monitoring & Control Program monitoring Legionella testing
FAH and/or ORP Maintain Total Bacteria Counts below 10,000 CFU/mL Frequency as required to maintain performance Treatment levels, system parameters, corrosion, fouling, etc. Legionella testing Random Legionella testing is not recommended Testing is recommended only after sterilization Control schemes Automation improves performance and efficiencies Wide range of controllers available Monitoring and control is the fourth component of our Best Practices program. Monitoring and control of critical parameters is key to maintaining any water treatment system. However, this aspect becomes more significant in a Legionella risk management program where system cleanliness and program effectiveness are so important. Monitoring critical water parameters as well as treatment levels is the only means of assuring program effectiveness. Routine microbiological testing is also required in order to assure that counts are being maintained at 104 CFU/mL or below. Random Legionella testing is not recommended for reasons noted in slide #24. Testing is recommended after sterilization to confirm effectiveness of cleaning. In the event a Legionella test is requested, Drew Industrial will expedite the request to a qualified, certified third-party lab following their specific sampling protocol. Of special note are the benefits achieved from automation. Automation enhances the precision and accuracy of monitoring and control on a continuous basis. Regardless of the type of application or price range requirements, Drew Industrial offers a complete array of automation capabilities.

45 Total System Approach: Five Areas of Activity and Performance
 Comprehensive system assessment  Intensive microbiological treatment program  Sterilization and cleaning  Monitoring and control  Documentation Drew Industrial’s Best Practices Legionella risk management program consists of five areas of activity and performance. While these areas are similar to our regular performance-based programs, the emphasis and focus is much more intensive in two areas: controlling microbiological and biofilm growth, and document actions. The five components of the our program are: 1. System assessment - This is a formal process for evaluating the critical factors of an industrial water-handling system in terms of mechanical, operational, environmental, and chemical treatment program. Factors are identified, evaluated, and rated in terms of conditions that can potentially favor Legionella growth and potential for exposure. 2. Intensive microbiological treatment program - Application of a customized, intensive microbiological treatment program specifically designed to control bacteria as well as control Legionella-harboring biofilms. 3. Periodic sterilization - The program focuses on minimizing the biofilm and other deposits that enhance Legionella growth. 4. Monitoring and control - An effective program is dependent on maintaining a consistent level of performance and control through routine monitoring of critical water parameters and system indicators. 5. Documentation - A thorough documentation package provides the necessary records that assure the proper precautionary measures and treatments are being implemented to minimize Legionella.

46 Use of Proper Monitoring & Control Equipment is Critical!
Microbiological Residuals, Corrosion, Scale & Biofouling Use of the right equipment is essential to implementing an effective monitoring and control program. Microbiological testing is critical to maintaining system cleanliness and controlling biofilm formation. Optional methodologies are available and range from simple assay slides, to plate counts, to rapid detection via the Bioscan ATP monitor. An assortment of water quality field testing equipment is available for monitoring residual levels and other critical water parameters. Corrosion and biofouling monitoring are also important parameters and can be monitored without a great deal of difficulty. Controllers range from simplistic, cost-effective “feed and bleed” units to complex, feed-forward, performance-based control packages with remote communications. On-line

47 ORP Halogen Control mV ORP PPM Halogen Fed 1 2 3 4 5 6 Break point
Break point (example only System specific) ORP Control Range ORP measures chemical oxidation potential Well documented sensor and control technology Provides amount of actual oxidation capacity of halogen regardless of form or dissociation vs. pH Relationship to FAH is dependent on individual system, chemistry conditions Each system has a specific ORP breakpoint and an effective level of ORP

48 Total System Approach: Five Areas of Activity and Performance
 Comprehensive system assessment  Intensive microbiological treatment program  Sterilization and cleaning  Monitoring and control  Documentation Drew Industrial’s Best Practices Legionella risk management program consists of five areas of activity and performance. While these areas are similar to our regular performance-based programs, the emphasis and focus is much more intensive in two areas: controlling microbiological and biofilm growth, and document actions. The five components of the our program are: 1. System assessment - This is a formal process for evaluating the critical factors of an industrial water-handling system in terms of mechanical, operational, environmental, and chemical treatment program. Factors are identified, evaluated, and rated in terms of conditions that can potentially favor Legionella growth and potential for exposure. 2. Intensive microbiological treatment program - Application of a customized, intensive microbiological treatment program specifically designed to control bacteria as well as control Legionella-harboring biofilms. 3. Periodic sterilization - The program focuses on minimizing the biofilm and other deposits that enhance Legionella growth. 4. Monitoring and control - An effective program is dependent on maintaining a consistent level of performance and control through routine monitoring of critical water parameters and system indicators. 5. Documentation - A thorough documentation package provides the necessary records that assure the proper precautionary measures and treatments are being implemented to minimize Legionella.

49  Documentation Maintain complete, accurate logs
Biocide usage Halogen tests and/or ORP log Bacteria counts Start-up and shut-down log Log of operating procedures Monthly service inspection reports System disinfection logs Contingency plans Documentation is the fifth component of Drew Industrial’s Best Practices risk management program. A complete and thorough documentation package is the “product” that demonstrates to any party that bacterial minimization measures are being practiced and maintained. Complete and accurate logging of all test results and records of all relevant actions taken are recorded to ensure maximum system cleanliness. Use of the DREW SYSTEMS MANAGER™ program, DREWTRAX® data management software, DREW™ Audits software, or plant data management systems should be used to collect, maintain, and manage all aspects of Drew Industrial’s Legionella risk management program. Use of these tools also helps in tracking system performance and identifying system trends so that preventative actions can be taken.

50 Problem Systems? Despite good control, monitoring and response, some systems remain problematic. Why? Cooling systems are dynamic Biofilms DO exist within system System contamination DOES exist Some system designs present obstacles to effective Legionella control Cooling systems are dynamic, and as a result, performance is not always consistent and predictable. Because of the facts noted here, some systems offer special challenges when it comes to control. Assuring that our five-component Best Practices Legionella risk management program is fully and consistently implementing becomes especially important.

51 Problematic Systems For these systems…
Maintain an environment hostile to bacteria at all times Continuously halogenate Continuously feed biodispersant Utilize reliable automation Utilize ORP control Regularly clean and disinfect Rigorously inspect and maintain

52 Risks Associated with Legionella can be minimized by:
Summary Risks Associated with Legionella can be minimized by: Surveying water system Evaluating key factors affecting growth Providing a comprehensive water management program Monitoring program for consistent control Documenting results and recording maintenance actions Maintaining Drew Industrial’s Best Practices Legionella risk management program

53 Legionella Risk Management Resources, Capabilities, Experience and Knowledge
Research & Technology Testing protocols, technical & microbiological details, non-standard program recommendations Best Practices Program Support System assessment scheduling, technical support, literature, seminars, training materials Program Management DREWTRAX™ and DREW SYSTEMS MANAGER™ data manager tools Field Expertise Dedicated account representatives and consultants for program setup, training, monitoring, product selection Advanced Water Treatment Technology Wide range of patented, high performance technologies for all applications including severely stressed conditions. Automation Complete selection of feed, control and monitoring equipment 1-800 Ashland

54 Drew Industrial’s Best Practices Legionella risk management program follows best practices designed to minimize conditions conducive to Legionella growth in cooling systems. When properly applied, our program is effective in reducing the potential for water systems to contain planktonic bacteria, biofilm, and other conditions that can harbor and protect Legionella for extended periods. Drew Industrial’s Best Practices Legionella risk management program, or any other program, will not eradicate Legionella bacteria. The goal is to take the necessary precautionary steps to minimize those conditions known to enhance growth and thereby reduce the potential for exposure. As documented by CTI, these recommendations should not be interpreted as a guarantee to completely eliminate Legionella bacteria or any other particular pathogen.

55 Survey of Field Test Results
In general it has been reported that 40 – 60% of Cooling Towers tested positive for Legionnella 794 evaluations performed 277 (35%) tested positive for Legionella Ranged from 1 to >9,000 CFU/ml

56 Detected Legionella Levels
<1-1 CFU/ml 2-9 CFU/ml 10-99 CFU/ml CFU/ml >=1,000 76 isolates 24 isolates 104 isolates 55 isolates 18 isolates 27.4% 8.7% 37.5% 19.9% 6.5% Based on 277 positive results 36.1% confirmed as <10 CFU/ML 26.4% confirmed as >100 CFU/ML

57 Legionnella Species Identifed

58 Response to a Positive Legionella Test Result
Action Level 1 - (Detectable - <1 CFU/ML) Risk Level - (Extremely Low) Confirm current treatment program Action Level 2 - (1 - 9 CFU/ML) Risk Level - (Low) Increase frequency of current treatment to one additional dose of biocide for two weeks

59 Response to a Positive Legionella Test Result
Action Level 3 - ( CFU/ML) Risk Level - (Low to Moderate) Increase treatment concentration and frequency to two additional doses of biocide weekly for two weeks Action Level 4 - ( CFU/ML) Risk Level - (Moderate) Increase treatment concentration and frequency to two additional doses of biocide weekly for 3 to 4 weeks On-line halogen addition / additional organic dispersant maybe required

60 Response to a Positive Legionella Test Result
Action Level 5 - ( CFU/ML) Risk Level - (Moderate to High) Hyperchlorination required possibly off-line Use Halogen at 0.2 – 0.4 ppm FAH continuous or daily shocks of 0.5 – 1 ppm FAH for 2 to 4 hours Action Level 6 - (>1,000 CFU/ML) Risk Level - (High) Use halogen continuously at 1 ppm FAH for 6 hours, then 0.2 – 0.4 ppm FAH plus feed non-oxidizer every apparent retention time for 1 week will be required Off-line sterilization using halogens at 5-10 ppm FAH for 6 to 24 hours, organics, and biodispersants may be required Retest in 1 week

61 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

62 Thank You ® Registered trademark and ™ trademark of Ashland Inc.


Download ppt "Legionella Risk Management"

Similar presentations


Ads by Google