Drew Industrial Ashland Canada Corp

LegionellaIn Light of Recent Events

LegionellaIn Light of Recent Events

®

Legionella BacteriaLegionella Bacteria

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

®

Factors Determining the Risk of Contracting the Disease

Factors Determining the Risk of Contracting the Disease

A source of Legionella

Favorable growth conditions

Aqueous aerosol

Sufficient organisms to cause

infection

Susceptible individual

®

Cooling towers Evaporative condensers Hot and cold water systems Taps and showerheads Humidifiers and air washers Spa and whirlpool baths Decorative fountains

Systems Promoting GrowthSystems Promoting 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

In order to minimize Legionella growth:

We know that…We know that…

®

Total System Approach:Five Areas of Activity and Performance

Total System Approach:Five Areas of Activity and Performance

Comprehensive system assessment

Intensive microbiological treatment program

Sterilization and cleaning

Monitoring and control

Documentation

®

®

System survey– In-depth survey of system mechanical layout 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

System Assessment System Assessment

®

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

“Ideal System”“Ideal System”

®

Susceptibility to Legionnaires’ Disease

Susceptibility to Legionnaires’ Disease

Age – The very young and +40 year olds Gender – Males are twice as likely to contract the

disease than females Heavy Smoker Heavy Drinker Individuals with weakened immune systems –

Cancer, AIDS, HIV positive Chronic Medical Problems – respiratory, diabetes,

asthma, renal dialysis Certain Drug Therapies – corticosteroids or other

immunosuppressive therapies Organ Transplants

®

Legionella Risk Management in Cooling Waters

Legionella Risk Management in Cooling Waters

Outbreak Potential is typically the cumulative effect of many high risk variables– Population of those whom are susceptible– Type of facility – Susceptibility of the cooling system– Microbiological control capability– Monitoring and inspection frequency – Documentation provides a management and

control feedback loop

®

High Risk FacilitiesHigh Risk Facilities

Hospitals Retirement Homes Long-term and chronic care facilities Public facilities

– Offices– Malls– Hotels

Process cooling systems that have the potential for:– Aerosol spray cooling – automotive– Process contamination

CPI/HPI Food/Beverages

®

Cooling System SusceptibilityCooling System Susceptibility

High airborne dirt load potential (utilization of side-stream filtration)

– Nearby construction– Lack of ground coverings with aggregate

materials or vegetation

High nutrient load potential– Process side inleakage– Tower near chemical, food or vehicle exhaust

®

Cooling System SusceptibilityCooling System Susceptibility

Cooling tower air discharge near proximity to fresh air intakes or open windows of building, and/or outdoor population

(i.e. ground level).

®

Cooling System SusceptibilityCooling System Susceptibility

No operation or intermittent operation of equipment while wet:– Drain if stagnant > 1 month– Idle - rotate weekly or install 5 – 10% slip

stream flow Dead legs or seasonal cross-over lines

– Remove them or– Loop them with 5 – 10% slip stream flow– Close shut-off valves at flowing supply and

drain the remainder of the branch system and equipment

®

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)

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)

Aerobic Bacteria Fungi

Anaerobic Bacteria

Higher

Life Forms

Flowing Bulk Water Basin Chip Scale

<10

1600

<10

10

<10

1,000,000

No

Yes

Basin Sludge 3,500,000 20 1,000,000 Yes

Dead Head (off) Plate/Frame XER

400 <10 10,000 Yes

Slip Stream By-pass (10%) Plate/Frame

<10 <10 <10 No

®

Microbiological Control CapabilityMicrobiological Control Capability

Efficacious biocides selection Biodispersant supplement for biofilm Effective application for required concentration and contact

time– System dynamics (ART, T½) and volume– Dedicated automated feed of microbiocides– Feedback control Loop (ORP, self verifying feed pumps)

Pre-conditioning/sterilization– Preseason start-up– Idle restarts– Sterilization/hyper chlorination at the summer peak– End of season shutdown

®

Microbiological Control Additives of ChoiceMicrobiological Control Additives of Choice

Oxidation– Bleach (CSW 20)– Sodium Bromide/Bleach (Drewbrom)– BCDMH (Biosperse 261T)– Chlorine Dioxide

Non Oxidants– Glutaraldehyde 1º (Biosperse 254/255)– Isothiazolin 2º (Biosperse 250)

Biodispersants– Nonionic Surfactants (Drewsperse 739)– Protein cross linking/cationic surfactant blend

(Performax 405)– Anionic surfactants (Drewsperse 7211)

®

Legionella Control with Non-Oxidizing BiocidesLegionella Control with Non-Oxidizing Biocides

Chemical Compound Active Concentration mg/ℓ Contact Time

Glutaraldehyde 25 - 54 1 Hour

Isothiazolin 2.25 - 2.6 6 Hours

2 Bromo-2-Nitro Propane-1,3, diol (BNPD)

25400

24 Hours60 Minutes

Dithiocarbamates 40.0 - 60.0 6 Hours

Di-bromo-nitrilo-propionamide (DBNPA) 4 - 8 2 Hours

Note: System potential contaminants and operational pH must be checked for compatibility with the non-oxidizing biocide

®

Continuous feed for chlorine, bromine, BCDMH or stabilized bromine– Dosage:

Recommended 0.2 - 0.4 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

*Alternative choices of non-oxidizing biocide should be based on Relative Population Density (RPD) lab results

Continuous Oxidant Feed Protocol

®

Intermittent Oxidant Feed Protocol Intermittent Oxidant Feed Protocol

Intermittent Oxidant Feed – Chlorine, bromine, BCDMH or stabilized bromine

– Minimum dosage: Hold 0.5 - 1.0 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

*Alternative choices of non-oxidizing biocide should be based on RPD results

®

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 DioxideA Selective Oxidant

Chlorine DioxideA Selective Oxidant

®

Continuous Chlorine Dioxide Feed Protocol

Continuous Chlorine Dioxide Feed Protocol

Continuous chlorine dioxide feed – 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

*Alternative choices of non-oxidizing biocide should be based on RPD results

®

Intermittent chlorine dioxide feed – 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.

Intermittent Chlorine Dioxide Feed Protocol

*Alternative choices of non-oxidizing biocide should be based on RPD results

®

Dual Non-Oxidizer Feed ProtocolDual Non-Oxidizer Feed Protocol

Slug feed of non-oxidizer– Alternately twice per week, evenly spaced– Timer/Pump (self verifying optional) automated

feed is preferred over manual

Oxidant feed once per week– Minimum dosage to hold 1 – 2 ppm FAH for 2

hours. Based upon system demand this may require the feed of 5 to 10 ppm active oxidant

– Dosing a day prior to a nonoxidizer addition is the preferred method.

®

Preconditioning and SterilizationPreconditioning and Sterilization

Frequency – Minimum once per year for season equipment

operation• End of season preferred

– Minimum twice per year for year round system operation

• During turn around on process systems and 6 months later

• Beginning and end of cooling season– Confirmed Out Break

®

Preconditioning and SterilizationPreconditioning and Sterilization

Procedure • Ensure all air intakes and windows within at

least 100 feet of the tower are closed• Open all cross over lines• Ensure complete recirculation of the total

system and all equipment• Turn fans off and activate stand-by pump• Blowdown flush all strainers, risers, water

boxes and dead legs.

®

Preconditioning and SterilizationPreconditioning and Sterilization

Procedure Cont’d• Add biodispersant (200 ppm) and non-oxidizer

recirculate for 24 hours (120 – 360 ppm)• Blowdown/flush etc.• Add oxidant to produce 5 ppm FAH (due to

system demand, dosage may be 15 to 25 ppm – 1.5 to 2.5 lbs. 10% bleach/1,000 gal) test verify 5 ppm at end of 6 hours

• Drain system blowdown/flush etc.

®

Preconditioning and SterilizationPreconditioning and Sterilization

Procedure Cont’d

• Water Wash/Hose out Tower Upper deck Drift eliminators Fill Sumps and companion indoor sumps and storage tanks

through to pump strainer

• If high pressure water jetting is employed then ensure suitable respiratory protective equipment is worn.

®

Preconditioning and SterilizationPreconditioning and Sterilization

Procedure – Cont’d• Leave drained for seasonal outage• If wet storage is employed, refill with inline

blend of protecsol and 300 – 400 ppm of 1.5 % Isothiazolin non-oxidizer.

• Immediate placement into service Refill Start pumps Slug feed corrosion and deposit control

compounds and non-oxidizer (i.e. prime the system volume)

®

Sterilization OnlySterilization 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.

®

Sterilization OnlySterilization Only Procedure

• Deconcentrate via bleed-off and blowdown of dead legs, risers, water boxes, and strainers to achieve 2 cycles of concentration. Close bleed

• Fans off • Add oxidant to produce 5 ppm FAH (Due to system

demand, dosage may be 15 to 25 ppm – 1.5 to 2.5 lbs/10% bleach/1,000 gal). Test hourly to verify 5 ppm held for 6 hours

• Blowdown dead legs, risers water boxes and strainers• Resume treatment program cycles of concentration• Add Non-oxidizing Biocide

®

Monitoring and InspectionMonitoring and Inspection

Inspection for visible slime or sludge's

– Decks

– Mist eliminators

– Fill

– Sumps

– Corrosion or biofilm coupons

®

Monitoring and InspectionMonitoring and Inspection

Testing• Bulk water dip slides

Prior to non-oxidizing biocide addition Minimum once per week Target ≤ 104 CFU/ml

• Coupon surfaces - if available Prior to non-oxidizer and/or biodispersant

addition Every 30 to 60 days, but be consistent Target ≤105 CFU/cm2

®

Direct Testing of LegionellaDirect 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

®

Legionella Testing – Pathcon/Biosans

Legionella Testing – Pathcon/Biosans

Ship via air direct

7 days to culture

If positive, species and type is determined, requiring additional time

E-mail results within 2 days after the 10th day after receipt by lab

®

OSHA/Wisconsin ProtocolOSHA/Wisconsin Protocol

Confirmed Cooling Tower Source of Outbreak1. Turn off tower fans

2. Shock dose chlorine donor to 50 ppm FAC

3. Add Biodispersant

4. Hold 10 ppm FAC for 24 hours

5. Drain cooling system and repeat steps 2 - 4

6. Inspect for biofilms. If present, drain and mechanically clean.

®

OHSA/Wisconsin ProtocolOHSA/Wisconsin Protocol

7. Refill system and operate for 1 hour at 10 ppm FAC

8. Flush system

9. Recharge system with water treatment additives for deposit, corrosion and biological control and return to service

Note test monthly:

Legionella ≤10 CFU/ml HPC ≤105 CFU/ml

®

Field Study on Biofilm GrowthField 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

®

DocumentationDocumentation

Why Document?• When a pneumonia outbreak occurs in a facility

it allows for: Speed in identifying the source for eradication

purposes, removing a potential and continual threat. After all it may not be cooling system derived.

Clinical micro biologists and physicians to select appropriate antibiotics, dosages and monitor the progress without the presence of further stressors.

®

DocumentationDocumentation

To name a few:• Simplified line drawing of the cooling system and all

equipment, dead legs cross over lines, chemical feed points/lines/control, system volume, recirculation make-up and blowdown rates

• Key water test results/date Chlorides or conductivity for cycles of concentration

assessment Make-up, blowdown water meter readings FAH and/or ORP for Halogen concentration Biological Tests – CFU/ml; CFU/cm2 Start, end and expiry dates of dip slide lots for bio testing

®

DocumentationDocumentation

To name a few:• Chemical pump and timer settings• Biocide usage• Start-up/shutdown and other application logs

of preconditioning/sterilization and sterilization only

• Inspection/observations for slimes, muds, algae in cooling tower and on coupons and what was done to improve

• Contingency plans procedures, and results/check offs when performed.

®

Use of Proper Monitoring & Control Equipment is Critical!Use of Proper Monitoring &

Control Equipment is Critical!

Microbiological

Residuals, Corrosion, Scale

& Biofouling

On-line

®

Action LevelsAction 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

®

Preventive ActionsPreventive Actions

Legionella is as Common as “Dirt” Keep Systems Mechanically and

Microbially Clean Minimize or Rotate Idle Equipment Employ Filtration and Keep Filter Media

Clean Mist Eliminators Clean and Functioning

Properly

®

Preventive ActionsPreventive Actions

Inspect and Test– Domestic Waters– Fountains– Spas– Air Handling Units– Humidifying/Dehumidifying Equipment/Coils

®

BiofilmsBiofilms

Biofilms Don’t Just Harbour Legionella, They:– Restrict Air Flow– Restrict Water Flow– Reduce Heat Transfer– Reduce Heat Rejection– Induce Localized Corrosion

Biological Control– Higher Life Forms – None– Bacteria CFU/ml <104, > 105 Do something– Bacteria CFU/cm2 <105, >106 Do something

®

Preventive ActionPreventive Action

Use your Biocides in a Prudent Manner

And Remember

Sterility Does Not Exist Except in Higher Life Forms

®

Additional Information Upon Request

Additional Information Upon Request

Legionella: Minimizing Risks, August 2000, Water Engineering and Management

Environmental Aspects of Legionnaires’ Disease, February 1988, Journal AWWA

Legionella Treatment Strategies: First Response and Minimization Action Plan, 2002 International Water Conference Paper 02-12

Who Should Be Responsible for Legionella, ASHRAE Journal May 1999, Volume 41, No. 5, 62-68, ref. ISSN-0001-2491

Why Evaporative Coolers Have Not Caused Legionnaires’ Disease, ASHRAE Journal, January 1995, page 29-33

®

Additional Information Upon Request

Additional Information Upon Request

Legionellosis, Guideline: Best Practices for Control of Legionella, February 2000, Cooling Technology Institute

Minimizing Risk of Legionellosis Associated with Building Water Systems, February 2000, ASHRAE Standard 12-2000 (ISSN 1041-2336)

®

What Can You AnticipateWhat Can You Anticipate

Expert group review of design and maintenance of cooling towers in long-term care homes, hospitals and other facilities housing people with complex health needs.

®

What Can You AnticipateWhat Can You Anticipate

Review of other existing HVAC/Legionella standards and development/adoption of a standard for use;

• ASHRAE Guideline 12-2000-

“Minimizing the risk of Legionellosis associated with building water systems”

• Cooling technology institute February 2000 Guidelines – “Legionellosis guideline: “Best Practices for control of Legionella”

• Health and Safety Commission, U.K., approved code of practice and guidance – L8, “Legionnaires” disease, the control of Legionella bacteria in water systems”

• The chartered institution of Building Services Engineers, U.K. TM 13- 2000, “Minimizing the risk of Legionnaires’ disease”

®

Walker ReportWalker Report

http://www.health.gov.on.ca/english/public/pub/ministry_reports/walker_legion/rep_intro...

Report of the expert panel on the Legionnaires” disease outbreak in the city of Toronto – September/October 2005, December 2005.

®

Industrial HygienistsIndustrial Hygienists

Employ Certified Industrial Hygienists Employ HVAC Engineers

– Can fully evaluate potable cold and hot Domestic Water systems

– Can calculate cooling tower plume relationships and re-entrainment of plume into air intakes or windows

– Can assess air handling systems

®

Industrial HygienistsIndustrial Hygienists

A firm such as:– Stantec Consulting – Resource Environmental Associates

Complete air quality, risk assessments on all aspects of exposure to Legionella and other environmental conditions such as molds and asbestos

Firms may also have a division that does complete sterilizations of systems – hot and cold domestic, air handling, etc.

®

AshlandAshland

Ashland is capable of a cursory review of cooling systems to assist a customer in targeting certain areas, as related to:– System Cleanliness– Microbiocide addition – whether oxidizing or non-

oxidizing biocide.– Capable of applying chemicals to meet the protocols –

continuous chlorination, shock feeding– Mechanical/operational conditions that can lead to high

risk– Assist in providing documentation tools – Can provide routine microbiological testing and has a

sample protocol and a lab arrangement to test for Legionella

®

Thank YouThank You

® Registered trademark and ™ trademark of Ashland Inc.© 2001 Ashland Inc.