PHYSICAL WATER CONDITIONERS How Effective Can They Be ? A Presentation for ASPE Jonny Seccombe...
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Transcript of PHYSICAL WATER CONDITIONERS How Effective Can They Be ? A Presentation for ASPE Jonny Seccombe...
PHYSICAL WATERCONDITIONERS
How Effective Can They Be ? A Presentation for ASPE
Jonny Seccombe
President
Aqua-Rex LLC
3301 Spring Mountain Rd Ste 18
Las Vegas NV 89102
949 887 2170
Learning Objectives
- Understand the Chemistry of Hard Water- Effects of Scale on Plumbing Systems- Ion Exchange Softeners – Pro’s & Con’s- Alternatives to ‘Salt’ Softeners – PWC’s -
How Physical Water Conditioners Work- Design – PWC location effects performance - Summary
The ChemistryCalcium Bicarbonate
(Dissolved)
Ca (HCO³)²Becomes
Ca CO³ Calcium Carbonate +(Solid)
CO² Carbon Dioxide +
H²O WaterTo Treat Hard Water - Either get rid of
Ca (Calcium) or HCO³Bicarbonate
TemperatureAbove 130 F
Pressure Drop
pH Increased
DUE TO
“Scaling Events”
Scale Sticks to Surfaces
Scale has to form onto something
It won’t spontaneously form onto itself
It has to have a surface or nucleation seed to form onto
Meldrum & Sear – Now You See Them
Science VOL 322 19 December 2008
Scale Sticks to Surfaces – So
• Plant Lifecycle Costs Increase – maintenance, replacements, flow rates
• Energy is Wasted– Limescale is 400 times less conductive of Heat than Copper. 1/8” of scale equates to 12% loss in heating efficiency,
• Pumps have to work harder in constricted pipes
• Hygiene is Worse – Scale traps dirt so cleaning is more difficult. Locker Rooms, Assisted Living, Dorms, Water Features
• Legionella Greater Risk – scale harbors bacteria
Regular Water Softeners Remove calcium by
“Ion Exchange” •Resin beads in Tank dosed with Salt
•Excellent Results
•Well proven technology
• But
•Requires Regular Dosing with Salt
•Plant Costs and Space useage
•Maintenance and Servicing
•Potability – Elderly and Infants
•Softener Bans – Chlorides!
Quote!“It’s a long time since I put in a pure
softener system”Paul Jolly
Senior Public Health EngineerWSP Group – Flack and Kurtz
July 2008Probably 95% of water treatment in Public Buildings,
Schools, Hospitals, Hotels & Defense Establishments In UK
is now done by
Physical Water Conditioners
Physical Water Conditioners
Create nucleation seeds that encourage scale to form in suspension rather than encrust surfaces.
•Nucleation Seeds – Many forms such as Zinc, Iron (Fe), Silico Phosphates plus others – some not yet identified.
Physical Water Conditioners
• Stimulate scale formation in SUSPENSION in the Water
• Instead of ENCRUSTATION on Surfaces
• The scale floating in the water is harmless – its good for you when you drink it
Two Stage Process•Stage One – Create the nucleation seeds
•Stage Two – Use a “Scaling Event” to create the scale on the nucleation seeds.
The closer together, in terms of time and distance, that these two events occur the
more effective the treatment is likely to be.
There is no detectable difference in the water, or its content, after stage one.
Magnetic / Electrolytic
•DC current or Dissimilar Metals•Corrodes Zinc (Coetzee et al.)
•Creates Zinc Hydroxide seeds•But•Finite amount of corrosion•Passivity – water quality?•Limited Effective Life•Unless Anodes are Cleaned or Replaced
Template Assisted Crystallization
• “New” Technology Using “Seeding” Media
• Conventional Tanks • Low Maintenance • But• Vulnerable to Contamination from Cu, Fe, Cl & Phosphates• Not clear when media replacement is required• Unpredictable Performance• Unreliable due to changing water quality• Withdrawn from UK market by Lifescience
Products due to lack of predictability
Electronic/Electromagnetic•Some induce an electro magnetic field
others Induce an electric charge•Act on ions already in the Water•Some Treat Static Water•Some Remove Existing Scale•Some are Non Intrusive –easy to retro fit•But•Durability of stage one can be limited•Effectiveness reduced in “clean” water•Correct Location on layout is VITAL
Factors to consider when Locating an
Electronic Water Conditioner
Cold Water Tanks – Cisterns
Booster Sets
Circulation Pumps
Re-circulating Systems – Cooling Towers Swimming Pools
Hot Water Return
Cold water services to mixing valves
ox
Primary
Secondary
Heat
Exchanger
Heat Exchangers
Water Heater Design is Significant –Do the scale particles accumulate in the bottom of the tank or does the incoming water stir it up? Can it get drawn from the tank into the water heater?
Find the Pump !
HOT
WATER
TANK
Can a Physical Water Conditioner
Soften Water?
If a device can stimulate scale formation in suspension and increase the amount of precipitation that takes place
Then
There will be less Calcium Bicarbonate dissolved in the water
The water will therefore be chemically softer although total calcium remains the same
It will behave like partially softened water
Weeks from 1 - 12
50ppm
Residual Calcium Bicarbonate
in Hot Water
100ppm
A WORD OF WARNING !!!!
Make sure YOU know what you are buying
It is quite possible that the Manufacturer doesn’t know what he is actually selling!
SummaryCalcium Bicarbonate (dissolved) makes water hard.
Calcium Carbonate (particulate) is formed when precipitation occurs – the scale once formed is effectively inert.
PWC’s use a Two Stage Process – They create Nucleation Seeds then a “Scaling Event” is needed to create the scale.
Magnets/Electrolytic Systems generally dose zinc hydroxide
Electronic/Electromagnetic – Act on salts already in the water. Location is critical
Preventing scaling using PWC’s -
Reduces energy consumption and lifecycle costs
Promotes hygiene & reduces the risk of legionella
Can produce most of the benefits of conventional water softeners but without generating chloride effluent - and at lower cost