Legionella Control – the options
•High and Low Temperature Regime
•Chlorine
•Copper/Silver Ions
•Flushing
•Trace Heating Elements
•Ultra-Violet Light
•Filtration
•Chlorine Dioxide
Legionella Control – the options
High and Low Temperature Regime
Biofilm
Raised temperatures – Scald Risks
Costly in Manpower and Energy
Relies upon Individuals
Relies upon System
Warm Temperatures encourage
Bacteria
Needs Good Record Keeping
Legionella Control – the options
Chlorine
Ineffective against Biofilm
Ineffective at Raised temperatures
Corrosive
Forms carcinogens THMs
Less effective at Higher pH
Legionella Control – the options
Copper/Silver Ions
Condition and cleanliness of electrodes
(scale)
pH of the water supply (>7.6)
Less effective against biofilm (UK BSRIA study)
Monitor Ag ion concn. at sentinel outlets
Ag not easily measured in the field
Not D.W.I. approved for prolonged use
Legionella Control – the options
Flushing
Needs to be regular and consistent
Often relies on a few individuals to
ensure it happens
Costly in terms of manpower
Can cause greater bacterial
proliferation
Legionella Control – the options
Trace Heating Elements
Do not resolve cold water issues
Reliability
Cost
Total coverage
Still same Problems with Temperature
regime
Legionella Control – the options
High and Low Temperature Regime
Biofilm
Raised temperatures – Scald Risks
Costly in Manpower and Energy
Relies upon Individuals
Relies upon System
Warm Temperatures encourage
Bacteria
Needs Good Record Keeping
Legionella Control – the options
Ultra-Violet Light
No residual value
Can be blinded by
particles
Does not remove
biofilm
Costly for large water
volumes
Point of use only
Legionella Control – the options
Filtration
Requires regular
maintenance
Not easy to fit to all
outlets and service
points
Legionella Control – the options
Filtration
Biofilm
Needs Constant monitoring
Costly in Manpower (filter changes)
Costly in Maintenance
Can become breeding grounds for
bacteria
Only works at Point of Use
Legionella Control – the options
Chlorine Dioxide
DWI regs. Max = 0.5mg/L (Total
Oxidants: ClO2, chlorite and chlorate)
HSE ACOP Min. = 0.1mg/L
US EPA. Max = 1.4mg/L
Chlorine Dioxide – what is it?
•A yellow - green gas with a chlorine like odour
•Is soluble and stable in aqueous solution
•In solution exists as a true gas
•Extremely effective and powerful biocide,
disinfectant agent and oxidiser
•2½times more powerful than Chlorine
•Cannot be stored in any great strength and
requires generation at point of use
Chlorine Dioxide – What does it do?
•Performance –
•Rapid kill of target organisms
•Legionella
•Cryptosporidium
•Campylobacter
•E-coli
•Pseudomonas
•MRSA
Pseudomonas
Chlorine Dioxide – What does it do?
•Performance –
•Rapid kill of target organisms
•Keep systems clear of biofilm and nutrients
•Cleans up already fouled systems
•Operate over a wide range of conditions
Concentration - Time - Temperature - pH
Chlorine Dioxide – What does it do?
•Performance –
•Rapid kill of target organisms
•Keep systems clear of biofilm and nutrients
•Clean up already fouled systems
•Operate over a wide range of conditions
•Not be affected by materials of system
construction
Chlorine Dioxide – The environment?
•Environmental –
•Minimal by-product production
•Chlorine dioxide and by-products do not
persist within the environment
•Easily neutralised
Chlorine Dioxide – How Do You Make it?
Generation
•Stabilised Chlorine Dioxide
•“Electrolytic” Generation
•“Catalytic” Generation
Chlorine Dioxide – How Do You Make it?
Concentrated Chemical Chlorine
Dioxide Generation
Capital Costs prohibitive
Size of Plant
Mixing of very concentrated Acids
High production of unwanted by-products
Unwanted reaction products
Reaction tricky to control
Very Concentrated Product
Chlorine Dioxide – How Do You Make it?
Stabilised or ‘Two Pack’ Chlorine
Dioxide Generation
Reacted
Chlorine Dioxide
and water mix
Water
Stabilised
Chlorine Dioxide
Activator
Chlorine Dioxide – How Do You Make it?
Stabilised or ‘Two Pack’ Chlorine
Dioxide Generation
Capital Costs low
Basic Technology
Mixing of concentrated Acids
Health and Safety Concerns
High production of unwanted by-products
Reaction tricky to control – unreliable
Concentrated Product
Chlorine Dioxide – How Do You Make it?
Electrolytic Chlorine Dioxide
Generation
Capital Costs
Complex Technology
Not Pure CLO2 – some by-product
Concentrated Caustic waste products
Prone to Water quality issues – electrolysis
Cannot be generated in high volumes
Cannot be injected into pressurised systems
Chlorine Dioxide
•Summary
•Versatility
Yes
•Performance
Yes
•Environment
?
•Safety
?
•Economics
?
Chlorine Dioxide
The Ideal Biocide?
The Next Generation – “Catalytic Chlorine
Dioxide” – The Process
Proportional Dosing
Cloxide R –
Sodium Chlorite
Precursor
Water Supply to unit
STEP ONE
The Next Generation – “Catalytic Chlorine
Dioxide” – The Process
STEP TWO
Proportional Dosing
Cloxide R –
Sodium Chlorite
Precursor
Water Supply to unit
Cation ionexchange
column
The Next Generation – “Catalytic Chlorine
Dioxide” – The Process
STEP THREE
Proportional Dosing
Chlorine Dioxide Product Stream
< 700 ppm
(Zero residual chlorite)
(>98.5% Chlorine Dioxide)
Catalyst Column
Cloxide R –
Sodium Chlorite
Precursor
Water Supply to unit
Cation ionexchange
column
The Next Generation – “Catalytic Chlorine
Dioxide” – The Process
STEP FOUR
Proportional Dosing
•Direct Injection into Mains Water
lines
•Injection into Water Storage
Tanks
•Protecting Fire Systems and
Storage tanks
•Multi-point injection from one
generator
•Impulse / Analogue / Analytical
methods of control
Cloxide R –
Sodium Chlorite
Precursor
Water Supply to unit
Catalyst Column
Cation ionexchange
column
•Interface to Building
Management Systems
•Data-logging for full audit trail
The Next Generation – “Catalytic Chlorine
Dioxide” – The Benefits
Lower Capital Costs
Simple Technology
Pure CLO2 – proven zero chlorite
The Next Generation – “Catalytic Chlorine
Dioxide” – The Benefits
Lower Capital Costs
Simple Technology
Pure CLO2 – proven zero chlorite
Highly Efficient >98.5% Conversion
Less Prone to Water Quality Issues
Can be generated in high volumes
Can be injected into pressurised systems at
volume
The Next Generation – “Catalytic Chlorine
Dioxide” – The Benefits
Cost Effective Technology
No Chemical Mixing
Safe Concentrations of Product @ 700ppm
Multiple Dosing levels
Greater Versatility
No Storage of Chlorine Dioxide
Easily Controlled
Chlorine Dioxide
•Summary
Previously
Today
•Versatility
Yes -
Yes +
•Performance
Yes
Yes +
•Environment
?
Yes
•Safety
?
Yes
•Economics
?
Yes
Chlorine Dioxide
The Ideal Biocide !!
Application of the ‘Ideal Biocide’
Hot and Cold Distribution Disinfection:-
Increased Removal of Biofilm in system
More efficient disinfection and better clean
Safer
Less Corrosive
Application of the ‘Ideal Biocide’
Constant Dosing - (in-line mains water injection)
Requirements:Water Supply (Water Quality) Regulations 1989
Regulation 25 –
Covers products approved for use in connection with the supply of
water for drinking, washing, cooking or food production purposes by a
water undertaker –
Section 7.A.1. States:‘Products based on chlorine dioxide must conform to the
specifications of BS EN 12671:2000 Chlorine Dioxide; BS EN 938:2000
Sodium Chlorite; BS EN 939:2000 Hydrochloric Acid, and:For products in section 7.A.1. The following condition also applies:the combined concentration of chlorine dioxide, chlorite and chlorate
should not exceed 0.5 mg/litre as chlorine dioxide in the water
entering supply.’
Application of the ‘Ideal Biocide’
Constant System Dosing:-
Total Removal of Biofilm in system
Bacterial Sterilisation
Safer water System
Greater Peace of Mind
Confidence in System Safety
Confidence in Regulatory Compliance
Application of the ‘Ideal Biocide’
Constant System Dosing:-
ACOP L8:
If an alternative biocide is used and proven
effective then temperatures may be reduced.
Application of the ‘Ideal Biocide’
Reducing Temperatures:
Less Man Power Costs
Less Reliance on System Capability
Safer – less scald risk
Potential Energy Savings
Application of the ‘Ideal Biocide’
Potential Energy Saving:
Hotel:
500 Residents using 100 litres Hot Water each a day
To Heat 1000 litres of water by 10 C = 11.6 kWH
@ £0.05 kWH energy.
Drop Temps from 60-50 C
Saving £10,585.00 per annum
Application of the ‘Ideal Biocide’
Building Services
Hotels
Barracks
Universities
Halls of Residences
Closed System Disinfection
Dental Chairs
Swimming Pools
Fruit and Salad Washing
Catalytic Chlorine Dioxide
in Action
Internal View
•Proportional Dosing
•ClO2 monitor for high protection
•Fully duplex system
•Fully automatic regeneration
•Advanced Digital dosing
technology provides a wealth of
control and auditable information
•Ultra-pure production of
Chlorine Dioxide at <700 mg/litre
•Zero residual chlorite
•Chlorine dioxide production on
demand. NO STORED
CHLORINE DIOXIDE.
•Ion-exchange produces ultrapure Chlorous Acid; the Catalyst
then completes and polishes the
reaction to Chlorine Dioxide.
Catalytic Chlorine Dioxide in Action
“from a small wash tank to a total site”
Clox-Cat –
X series
•Exchange Column
•No regeneration on-site
•Will treat up to 4,000 m³ at
1.0ppm Chlorine Dioxide
between column exchange
Controlling the ‘Ideal Biocide’
Wafer:
Optional
Chlorine Dioxide
Catalyst Column expiry
warning (100 hrs)
Modem Link via
SIM or Land Line
Impulse Water
Meter (or Flow
Sensor)
Visual or Audible Alarm
Chlorine Dioxide Probe
and Flow Sensor
Digital Dosing Pumps
Chemical Stock Tanks
Clox-Sys