T.P. Technology plc (Tarn-Pure TM )
Legionnaire s Disease What is it? Where is it found? Methods of control Hot & cold water systems in hospitals, hotels etc Fountains & water features Vehicle washers Dental surgeries Food cabinet vaporiser systems Cooling towers
What is legionnaires disease? Serious form of pneumonia, mortality rate in the order of 10-15% in otherwise healthy individuals. Symptoms include a flu-like illness, a dry cough and frequently progress to pneumonia. Approximately 30% of people infected may also present with diarrhea and vomiting and around 50% may show signs of mental confusion The incubation period normally 2-10 days with 3-6 days the typical illness onset time. Legionellae were first detected in 1976 after a particularly notable outbreak of pneumonia in a hotel hosting a United States Army veterans meeting. Since that time, it has been established that these organisms are an important cause of pneumonia, both community-acquired (1 15%) and hospital-acquired(up to 50%). AEROSOL WHO Guidelines for Drinking Water Quality European Guidelines for Control and Prevention of Travel Associated Legionnaires Disease
Legionella natural history of the organism: Legionella bacteria are common. Found naturally in environmental water sources such as rivers, lakes and reservoirs. Organism passes into sites that constitute an artificial reservoir (town water supplies, water systems in individual buildings, etc). Water temperatures in the range of 20 C to 45 C favour growth. Organisms do not appear to multiply below 20 C. Organisms will not survive above 60 C. Remains dormant in cool water and multiply when water temperatures reach a suitable level. Zzzz Zzzz Zzzz <20 o C - Dormant 20 o C - 45 o C Favours growth >60 o C - Dead
Legionella bacteria also require nutrients to multiply, and sources include commonly encountered organisms within the water system itself such as algae, amoebae and other bacteria. The presence of sediment, sludge, scale, rust and other material within the system, together with biofilms, also play an important role in harbouring and providing favourable conditions in which the legionella bacteria may grow.
England & Wales - Cases by year of onset 250 200 150 100 50 0 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Hot and cold water systems - Hospitals, Nursing/Care Homes, Schools, Leisure Centres, Hotels and Industry Fountains/Water Features Vehicle Washers - car, truck and train Dental Surgeries Where is it found? Food cabinet vaporizer spray systems Cooling Towers and Evaporative Condensers
Three methods of control: Thermal Chemical Ionisation
Thermal treatment Pasteurisation - This can be used periodically or following a positive incident but is not a continuous process. Elevate stored and distributed water temperature to give 5 minutes flow at minimum 60 o C at each outlet Temperature Regime Traditional approach Hot water stored at 60 o C, return must be 50 o C Outlets must reach 50 o C within 1 minute Cold water to be maintained below 20 o C Risk of scalding therefore TMV s s fitted
Dr. John V. Lee Water & Environmental Microbiology Reference Unit, Central Public Health Laboratory, Health Protection Agency
Cold Water Down Service Each arm of the valve contains a check valve to prevent cross flow from hot to cold. However, these are easily blocked by grains of calcium or other debris in the water and this can cause cross contamination from hot supply to cold and flow of cold water to hot water system.
Temperature Treatment - Pro s s & Cons Familiar Simple to operate and monitor Effective in hot water Does not penetrate to all areas, especially beyond TMV s s and on long runs TMV s s expensive to retro fit and expensive to maintain Difficult to control in cold water systems
CHEMICAL There are two ways of using chemicals: Disinfection (Chlorination) - Used periodically or after a positive incident. Storage tank dosed to 20-50mg/l free chlorine. To all outlets until Chlorine smell Leave for 1-2 hours Neutralise & flush Treatment regime - Most commonly Chlorine Dioxide Inject into incoming supply or water storage Must achieve 0.5mg/l at outlets Tendency to gas off in hot water
Typical Chlorine Dioxide Injection Systems
Chlorine Dioxide Pro s & Con s Less corrosive than chlorine Effective Lower capital cost Requires COSHH compliance in storage and handling Possible increase in corrosion risk Requires regular revenue expenditure, delivery etc. Health risk if overdosing occurs.
IONISATION Electrolytic generation of silver and copper ions The positively charged ions are attracted to negative charge sites on the bacteria cell walls, distort the cell structure which prevents the absorption of nutrient and causes the cell to die. Minimum of 20µg/l - 40 µg/l silver, 20mg/l - 40mg/l copper Can be installed in incoming main, hot water system or cold water storage Not affected by temperature or sunlight
Process Approval Health & Safety Approved Code of Practice for The Control of Legionella Bacteria in Water Systems L8 European Guidelines for Control and Prevention of Travel Associated Legionnaire s Disease published by the European Surveillance Scheme Guidelines for Drinking Water Quality Addendum for Microbiological agents in drinking water published by the World Health Organisation Health Technical Memorandum 04-01: The control of Legionella, hygiene, safe hot water, cold water and drinking water systems Published by NHS Estates
Po we r Set O u tp ut Pol ar ity Ala rm Se t Lo w High Op er at in g Ho ur s Tarn-Pure How do we do it? Al a r mal a r Hi m gh Low Tarn- Pur e Hi gh Of f O n Two electrodes which are an alloy of silver and copper and one electrode which is titanium are assembled into an electrode cell. Then the electrode cell is fitted in the water system to be treated and water passes through the cell and between the electrodes We then apply a d.c. current across the electrodes and this causes the release of silver/copper ions into the water
Typical Electrode Cell
Cut-away cell showing electrodes in-situ Selection of electrode cell styles
Power indicator illuminates when unit is switched on Output Voltage digital display -- voltage will increase to maintain correct output current Output Current digital display indicates current applied to electrodes and is proportional to rate of ion release Flowmeter Function Switch to Fitted when 4 20mA Flowmeter input is used. Depress and hold to set output current required at simulated maximum Flowmeter reading Polarity Status lamps illuminate alternately to indicate correct polarity change to electrodes Adjust to set Output Current Set Service Warning lamp operation point Bi-Level Output Set to On when using timer control to operate system at a lower secondary level such as overnight or at weekends Set secondary output level Records total running hours of equipment Main On/Off switch
Dr. John V. Lee Water & Environmental Microbiology Reference Unit, Central Public Health Laboratory, Health Protection Agency
Silver/Copper Ionisation Pro s & Con s Marginally higher capital cost but lower revenue Must be properly monitored and maintained Although fully approved and in use since 1980 still viewed as new technology and therefore with suspicion No COSHH requirement Very low maintenance compared to TMV s No replacement electrodes for average 2 years Low installation cost Lower hot water temperature reduces growth rate of Calcium scale Effective against Legionella, e-coli, pseudomonas, listeria and most know water-borne bacteria and virus Safely operating hot water at lower temperature reduces losses and is more energy efficient
Flowmeter Output Voltage Bi-Level Output Operating Hours Mi Flowmeter Tarn-Pure Hot / Cold Water Systems Main Supply Cold Water Tank Pump Cell Laundry Kitchens Bedrooms Baths & Showers 5 0. 0 Tarn- Pure TM Tarn-Pure Control Unit Calorifier Tarn-Pure Control Unit n Tarn-Pure TM n Mains Power Cold Water Down Service By-pass Valve Electrode Cell Existing Hot Water Circulation Pump
Flowmeter Output Voltage Bi-Level Output Operating Hours Tarn-Pure Incoming Main Supply 50. 08.0 0 Control Unit Tarn-Pure TM Water Provider Non return or double check valve Flow meter or flow switch Titan Caution Switch off power at Control Unit before removing cover Building Services
Control Unit Electrode Cell Flow Meter Incoming Main to a Leisure Centre
Cold Water Storage Tank at a Cambridgeshire NHS Day Hospital
Cold Water Storage Tank Tarn-Pure Control Unit Tarn-Pure Electrode Cell Installation on Cold Water Storage Tank
Installation on Incoming Main of major UK NHS Hospital Installation on Hot Water System of large Italian Hospital
Electrode Cell in Hot Water Circulation System
Electrode Cell on Hot Water Return
Hot Water Installation
Hot Water Installation in USA Hospital
Fountains & Water Features Fountain or Water Feature Circulation Pump Tarn-Pure System Se t O P Filtration
Car, Lorry, Bus and Train Wash Systems
Underground Dirty Water Sump Centrifugal Separator Bank To Waste Control Unit Reclaim Tank in Plant Room Activated Carbon Filter with Auto Backwash New Pump Ready to Use Tank in Plant Room Water Softener Mains Supply Top-up From Low Level Sensor On - Timer Electrode Cell
Flowmeter Output Voltage Bi-Level Output Operating Hours Tarn-Pure Disinfection agent added Sump Filter Tarn-Pure 5 Control Unit 0. 0 Tarn- Pure TM Cell Installation of Tarn-Pure to water storage tank
Bacterial Quality of Sprayed Water: - The Challenge
Where washes are mains supply only, the risk of bacteria growth is minimised. Where partial or full recycling is used there is clear risk of growth of Legionella or other forms of bacteria in the sump and water storage areas, especially in locations where the water temperature can rise. Stored volume is usually sufficient for 5 10 wash cycles so for a train or truck wash this could sit for a few days before being used, particularly over weekends or bank holiday periods. Anecdotal evidence suggests that many wash operators, particularly car wash systems, fit recycling systems but isolate them until a drought order comes into force. The system is then bought back online and the bacteria that has accumulated in the storage tank released into the atmosphere.
In general, these systems have been shown to present a potential risk to health and as such should be maintained in a clean state. They will often require regular disinfection and should be monitored on a regular basis where appropriate. There is a duty of care to carry out a risk assessment and to maintain records of all maintenance that is carried out together with monitored results. For commercial wash systems a duty of care should be taken for both employees and others in the local environment; due consideration must be given to the surroundings private dwellings, offices, retail outlets, etc.
Dental Surgeries
Aerosol from high speed drill
Aerosol generated by Rinse Jet
Aerosol generated by Ultrasonic Cleaning Head
Internal plumbing of dental pedestal
Food Cabinet Vaporizer Sprays Misting, atomisation or fogging sprays are used in display cabinets for salad products in restaurants and hotels, meat and fish counters in retail outlets and in vegetable displays in markets and supermarkets. They have two uses: - to keep the product moist and fresh - to make it look appealing to the consumer However if the water quality is not good the product will suffer but if the water contains Legionella bacteria the spray will be harmful to consumers close to the display who inhale the mist.
Flowmeter Output Voltage Bi-Level Output Operating Hours Tarn-Pure Air Outlet Return Typical Cooling Tower Application Flow Pond Air Inlet Probe Conductivity Control PH Control Injector Pump Acid Electrode Cell 50. 08.0 0 Pump Titan Caution Switch off power at Control Unit before removing cover Tarn-Pure TM Probe Centrifugal Separator Control Unit Drain Motorized Conductivity Bleed Valve
Other applications include: Salad Washing for major supermarket chain Swimming Pools Water features in shopping centres such as the Trafford Centre and Bluewater
A small selection from our extensive client list Health Sector Leicester Royal Infirmary 15 installations since 1992 Queens Medical Centre, Nottingham, 3 systems Peterborough Hospital, 4 systems Mile End Hospital, one large system for site St. Georges Hosp. Hornchurch, large system for whole site Birmingham Dental Teaching Hospital hot and cold water storage Surrey & Borders NHS Trust 4 sites Housing & Accomodation Housing Association in London- 10 blocks flats of 130-160 apartments each block Cheval Group, 8 systems including three blocks of luxury apartments and a hotel in central London Circle Anglia 9 sheltered housing units of 40 60 flats each Sue Ryder Care Homes-3 sites Freemantle Trust Aged Persons Homes - 3 sites Borough Care Services 6 sites Lundy Island community water storage Public & Commercial Sector Trafford Park - public water features Prescoed Prison, Wales - whole site for prison & YOI Nissan - car body wash plant National Museum of Wales main water supply Birmingham City Council Redfern Road dustcart wash & Lifford Lane dustcart wash Approximately 40% of production is exported via distributors in USA, Spain, France, Australia, Sweden, Italy, Ireland & Holland
Tarn-Pure has been manufactured in the UK since 1980 and has active distributors and installations in the USA, Spain, Italy, Turkey, Czech Republic, Australia, Scandinavia, France, Irish Republic. The manufacture of Tarn-Pure equipment and its installation, operation and service is carried out to the highest quality. Our product and process approvals shown below ensure that you will be provided with the best product and service available in the control of Legionella.
Simple to install Low maintenance Low revenue cost Benefits Reduced hot water energy costs Lower hot water temperature reduces growth of calcium scale in pipes and equipment Themostatic Mixer Valves not required Protection from Legionella, e-coli, pseudomonas, salmonella etc.
For details of purchase, leasing, installation and maintenance options please contact: T.P. Technology plc High Wycombe, Bucks, HP12 3HE Tel: 01494 535576 Mobile 07860 693581 Fax: 01494 464175 e-mail: ian.bateman@tarn-pure.com Web: www.tarn-pure.com Local area distributors for former Yugoslavia: UNINVEST d.o.o. Ferrarska ul 14 6000 KOPER SLOVENIJA Tel: +386 5 66 35 400 Mobile:+386 41 403 792 Fax: +386 5 66 35 410 e-mail: info@uninvest.si Web: www.uninvest.si