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DAISY pool water treatment

Dryden Aqua Integrated System

howard dryden

on 30 May 2014

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Transcript of DAISY pool water treatment

1 x bacteria can grow into
20 million in 8 hours

Active Filter media

sand filters

and the

biology of pool water treatment
Water treatment after Dryden Aqua
Turbidity is mainly caused by dead bacteria and bits of bacteria cell wall, almost as dangerous as living bacteria.

Pools must have low turbidity to be safe.
1. Operate both private and public pools and recycle 100% of the water
2. Reduce the operating costs by approx 30%
3. Up to 90% reduction of toxic disinfection by-products
5. Eliminate bacteria not only in the water but on every weted surface.
6. Makes for a better and safer swimming experience with.....

.....Crystal Clear Sparkling Water
The heart of the system
AFM-activated filter media
Sand after 3 days of use
forms a Biofilm on the surface
Sand filters are Bio-mechanical
Public pool: 800 visitors / day; zero turbidity; almost zero water consumption
UK team train in an AFM pool in Edinburgh
Dutch Olympic team train in an AFM pool
1m3 sand has a surface of 3000m2. This is the largest area in a swimming pool.
Example: 25 x 10m pool - 350m2 surface area
Sand surface (6 m3 sand): 18'000m2

Pool area: approx 350m2
Piping system surface : approx 100m2
=> Filter material is more than 90% of the surface.
The sand in the filter is a perfect surface for growing bacteria
=> Result: No Biofilm - no or significantly less Trichloramine.
A proportion of urea is converted to ammonium.
Ammonium reacts with chlorine to form monochloramine and dichloramine.
The formation of Trichloramine occurs mainly at pH values ​​below 5.5.
The primary environment in a swimming pool where we have acidic conditions, the biofilm.
Biochemical relationships
APF coagulation reactions remove dissolved organics.
APF polyelectrolytes trap particles most particles >0.01 micron
The water flow after the ZPM must be gentle, avoid multiport valves. It also takes time, so use DIN spec filters.
APF must be injected into a ZPM to mix the products and to initiate the coagulation reactions

The ZPM aggressively shakes water and changes the zeta potential on particles to cause flocculation.

Milk is an example, change some of the –ve charged oil droplets are to +ve charge by shaking it and you form butter.
Optimised coagulent & flocculant
All Poly Floc
DAP 6 - +10
DAP 6 - 8
DAP 3 - 6
DAP 1 - 4
Chlorine in kg
Dryden Aqua Integrated systems have the lowest chlorine and chemical demand
can not penetrate the biofilm, it is sufficiently stable to protect the bacteria.
Bacteria stick and grow on most surfaces.
Bacteria secrete a mucus to protect themselves against chlorine oxidation
Chlorine 50 ppm
Bacteria cling to surfaces
(walls, floor, pipes and sand in the filters) Through natural selection biofilm will become almost completely resistant to chlorine.
How bacteria survive in a swimming pool?
50 ml Urine
Source of nitrogen for one hour in the water
Amino Acid
200 ml Sweat
Channelling in the filter bed
Anoxic zones in the filter bed
Biofilm can lead to anoxic zones, and coagulation of sand leading to channel formation
Pseudomonas Staphylococcus and Legionella are discharged into the pool
Urea from the bathers
Urea from bathers feed bacteria
Urea changed by bacterial enzyme to ammonium
Ammonium reacts with chlorine in the acidic biofilm to form trichloramine (combined chlorine)
Biofilm on sand
Surface of sand or any surface in a swimming pool
Trichloramine combined chlorine in the water. Volatile gas which enters the air to give pools a chlorine smell. Causes eyes, skin and lung issues
Ammonium and chlorine at low pH
APF + ve charge flocculated particles and dissolved organics are adsorbed
Electro-mechanical adsorption
Marine mammals in captivity living in chlorinated water need the:
Best water treatment
Best water quality
NO disinfection by-products
Dryden Aqua are marine biologists
Private pool 3m deep zero turbidity
Very low dissolved organics turns water sparkling blue
No biofilm, not even on the stone work
25m+ visibility
Dryden Aqua Integrated System (DAISY)
Better air quality
Better water quality
Lower operating cost
Coagulation and flocculation

What is APF
Zeta Potential and flocculation
Most of the particles and dissolved components, have a – ve charge. APF and NoPhos neutralise the charge

The +ve and -ve particles attract to form larger particle that are then easier to filter out of the water.

AFM filtration with APF will remove most particles down to 1 micron and most sub-micron particles as wells as many chemicals in solution.

A high +ve or –ve zeta potential will give a colloidal suspension and turbid water.

A neutral zeta potential around pH 7.1, will provide the clearest possible water. It is therefore important to apply the correct dose of APF in accordance to the Goldilcocks equations, not too little or too much but just the right amount.

What does it mean for swimming pools
The less chlorine used the better the better the water treatment system
3. Flocculation of coagulated particles

1. Zeta potential neutralisation
The only physical mechanism to removed dissolved chemicals
The +ve of charge electrolytes Aluminium chloride and NoPhos neutralise the charge, then Van Der Waals forces brings them together to form a small floc.

The polyelectrolytes in APF then grow the floc.
1. Alkalinity is required to drive the hydrolysis precipitation reactions. Alkalinity should be above 50 mg/l.

2. Hardness with calcium & magnesium promotes cross-linking, charge neutralisation and greatly improves performance, should be above 100 mg/l (>5 German scale)

3. 1ml per 1m3 of water filtered per hour, for APF private and public

4. The dosing of APF must be continuous using a peristaltic pump, a solenoid should not be used

5. There must be a non return valve on the end of the injection hose
Coagulation and flocculation aids
just the right amount of APF
showing APF
and ACO injection

Some combine chlorine, organo-chloramines are very stable, and do not easily break down. These chemicals are non toxic as combined chlorine

The chemicals will take very high concentrations often greater than 10mg/l to oxidise and the end products are usually carbon dioxide, nitrogen gas, water and hydrochloric acid

When we recycle all the pool water, then other organics such as pthalates start to become an issue. These chemicals are non volatile, and very stable yet they react with DPD3 to give false high readings

Oxidation of persistent hard organic chloramines is accomplished by the DAGen by Electron Abstraction Oxidation

Organo chloramines

Dissolved chemicals and some solids that remain in the water will be subjected to chlorine substitution oxidation reactions.

Chlorine oxidation forms combined chlorine

Volatile Chlorine substitution disinfection by-products are all toxic to varying degrees.

It is therefore essential that the removal of solids and dissolved chemicals are as efficient as possible in order too minimise chlorine demand, and formation of disinfection by-products.

The dissolved components are removed as volatile as volatile end products, or as complete oxidation as N2, CO2 & H2O

Chlorine oxidation reactions

A fundamental shift in pool design
… the control of dissolved chemicals

DaGen can supply 100% of the chlorine demand of a public or private pool

Additional chlorine injection may be required during peek demands.

If all the water is recycled then no salt addition is required

Reduced pH coorrrection

All the water in the pool is treated every 24 hours and returned to zero combined chlorine

There is literally nothing left in the water; No turbidity, No Bacteria, No Urea, No Combined chlorine

Key Points


2. Physical removal of dissolved chemicals

Very important that APF is injected via a ZPM in order for the coagulation reactions too work

APF must be used at the correct application levels, monitor alumium levels in the pool about once per week. A small quantity of aluminium should always be present.

A non return valve or duckbill must be used for the injection nozzle to prevent the pool water reacting with the APF before it has a chance to react with the pool water in the ZPM

Do not dilute APF

Continuous dosing

1 ml per cubm/hr

APF optimisation

Cathode: 2 H+ (aq) + 2 e− → H2 (g) hydrogen at the cathode

Anode: 2 Cl− (aq) → Cl2 (g) + 2 e− chlorine and hydroxyl radical at the anode
H2O →OH. = H+ + e-

Overall process: 2 NaCl (or MgCl2) + 2 H2O → Cl2 + H2 + 2 NaOH chlorine gas and
caustic formed

Cl2 + H2O  →  HCl + HClO hydrochloric acid and hypochlorous formed, hydrochloric acid reduces the requirement to add acid

Cl2 + 2 OH– → ClO– + Cl– + H2O hypochlorite and chloride formed, the chloride gets recycled

Inorganic and organic chloramines -> oxidised back to hypochlorous at the anode.


DaGen will produce Hydroxyl radical, OH. The hydroxy radical wants / needs and electron to be come a hydroxyl ion. The definition of oxidation is loss of an electron, not the addition of oxygen.

The hydroxyl radical OH. Has a much higher oxidation potential than ozone at 2.86 v. It simply converts NOM back to N2g CO2g and H20.

There are no disinfection by-products

Radicals (often referred to as free radicals) are atoms, molecules, or ions with unpaired electrons or an open shell configuration. Free radicals may have positive, negative, or zero charge. With some exceptions, these unpaired electrons cause radicals to be highly chemically reactive.

Free radicals






Formation and degradation of inorganic chloramine

Nano vapour bubble thermal nuclear fusion implosion
Physical removal of solids
Colloidal turbidity is caused by bits of skin cells, bacteria and bits of bacteria.

A low Zeta potential gives a low turbidity and high redox potential

The control of the Zeta potential is accomplished by ZPM and APF.

Before the filter we want a low zeta potential - after the filter is a high negative zeta potential.

Bacteria and viruses can not adapt to a changing of the Zeta potential.

Change the Zeta-potential

Cloudy water is pumped through the ZPM. The ZPM creates an artificial cavitation. The molecules are moving strongly, electrons are stripped off.

Changing the Zeta-Potentials
Creatine + 9HOCl -> 5CO2 + 2N2 + 9HCl + 2H2O

 CH3CN + CO2 + 2HCl

Chlorine oxidation reactions
Chlorine oxidation substitution reactions work by converting the dissolved chemicals into combined chlorine.

Urea becomes dichlorurea it is unstable and ends up as nitrogen trichloride, nitrate and some nitrogen gas

Ammonium becomes nitrogen trichloride and is lost to atmosphere

Amino acids e.g alanine, glycine, valine, tryosine could end up as acetonitrile and

then eventually chloro and dichloro-acetonitrile that are toxic

Creatine forms very stable chloro-creatine compounds that are stable and exist well beyond break-point, up to 15 mg/l chlorine, eventually they ends up as carbon dioxide and nitrogen

Chlorine Demand
Over 90% of the chlorine demand in pools will be from chemicals in solution not particles in suspension

Biological water treatment by sand filters
Swimming pools using sand filters are biological treatment systems. You can not stop bacteria growing on sand. The bacteria eat the dissolved nutrients and convert into more bacteria
Biological …. Bacteria eat dissolved nutrients and turn them into more bacteria, numbers double every 30 minutes.

Electrochemical - mechanical treatment by AFM
AFM is a non-biological process, so dissolved nutrients such as ammonium, urea , amino acids, creatine and peptides etc, have to by removed by:

Physical removal …. Coagulation and flocculation
Oxidation …. Chlorine substitution oxidation by hyopochlorous
Oxidation …. Electron Abstraction Technology (EAT)

Physical removal of solids
The ZPM is essential for the proper functioning of APF

The ZPM shakes the water and drops the Zeta potential to a more neutral condition, this causes flocculation without chemicals.

The ZPM mechanically coagulates and flocculates the water.
As Zeta potential goes down redox potential goes up, so the ZPM also disinfects

pool water
plant room

The ZPM cavitates the water to make water vapour filled nano bubbles.

The vapour condenses and bubble implodes generating a jet that can blow a hole through an oocyst or bacteria.

When a bubble implodes it gives a flash of light, temperature is over 2000 deg C at over 1000 atms

Busy pools may need some help

Our Technology
is leading Europe
AFM best Pool product in Europe 2009

Chartered Institute of Water & Environmental Management of the UK commendation awarded Dryden Aqua

ZPM cavitation
Blows a hole in oocycts and bacteria
The greater the delta P across the ZPM the more cavitation.
1. Zeta potential is the electrical charge on all particles in the water

2. The ZPM is essential to violently mix the electrolytes in APF and to make the product work

3. Essential for the reduction in combined chlorine
Physical removal of dissolved chemicals
activated filter media
Chlorine at low concentrations will kill most individual bacteria in under 30 seconds.
Biofilm on the surface of sand is acidic around pH 5. Ammonium and chlorine react to form...
Is changed to ammonium by bacterial
urease enzymes in the biofilm
Nitrogen trichloride
or trichloramine
Individual bacteria are killed in seconds, but most bacterial will be in floc as colonies of a million or more bacterial. In floc they can survive for a few minutes to hours

.... the second ZPM deals wit floc
No Biofilm
AFM, introduced new
AFM after 5 years in
a wastewater treatment
No biofilm
No amoebae
No Legionella
AFM = 18 bacteria on 5 g of media
Sand = 3,6000,000 bacteria on 5 g sand

Samples taken 250mm below the bed surface after a back-wash
2. Coagulation
too much APF
too little APF
high +ve zeta potential
high -ve zeta potential
A low zeta potential gives clear water
The ZPM with APF injection needs to be earthed to dump –ve charged electrons to ground. This drops the -ve zetal potential of the water to a more neutral condition.

APF or any flocculant will not work unless it is mixed with the water. The ZPM performs this task

The ZPM is not an ordinary static mixer, the configuration of the internals causes cavitation and the formation of nano-bubbles that can kill parasites such as crypto and giardia
Electrically Earthed
They will remove particles from the water


Sand acts as a substrate to incubate bacteria that;

increase the chlorine demand
generate disinfection by-products
Pathogenic risk
Endotoxic and exotoxic risk
Sand filter are Bio-Mechanical
ZPM smashes floc into individual bacteria that are easy to oxidise.

ACO injection increase -ve zeta potential

ZPM is not earthed so -ve charge is maintained and Zeta potential is high but water filtered.

Bacteria can not grow in water with a high zeta potential, just like the surface of AFM
1. APF injection between pump and filter.
2. ZPM before using the AFM filters
3. Replace sand with AFM
4. ACO dosed according to the AFM filters
5. Use ZPM
DAISY components on an Integrated system
Life cycle costing
Why use APF ?
...reduction combined chlorine
...it's essential for sparkling water
...cryptosporidium, giardia and bacterial control
selection of electrolytes including aluminium chloride and NoPhos


coagulation reactions
Polyelectrolytes for flocculation reactions to remove suspended solids and parasites
APF Improvements
When APF is added to water, the aluminium is hydrolysed.

This consumes alkalinity and pH becomes more acidic.

The chemistry of APF has now change to help reduce the pH suppression
DPD 3 analysis, over estimates by at least 300% against MIMS, membrane introduced mass spectrometry, from Bletchley 2009.
Metals also interfere such as Titanium dioxide in ACO and to a lesser extent Aluminium in APF.
Under standard procedures, use EDTA to chelate metal ions before you proceed with DPD analysis.

DPD Interference

Eliminate biofilm and control  Pseudomonas | MRSA | Legionella | cryptosporidium | giardia  and reduce chlorine disinfection by-products.

Control of biofilm

The pool is not a toilet

>95% of the surface area in contact with the water is the filter media, and this is where the bacteria are located unless AFM is used in the filters.

How can we reduce the Chemical Oxidation Demand and production of Disinfection by-products

All bathers must shower, this removes
75% of all the nitrogen. Do not allow the use of shampoo before entering pool.

0.06 atm

Inorganic chloramines

UV reaction product
Very toxic

Cyanogen Chloride 108 atm UV reaction product very toxic, does not react with DPD

Methylamine Dichloramine
CH3NCl2 154 atm

Chloroform 185 atm
UV reaction product does not react with DPD

Chlorourea Very soluble
in water, reacts with DPD

Nitrogen Trichloride
435 atm reacts with DPD

1.5 atm reacts with DPD

Disinfection by-products & henry`s constants,
the more volatile the DBP, the greater the potential toxicity

0.45 atm reacts with DPD

Also essential for the water to be safe;
especially in public pools
co-precipitants... NoPhos
coagulants.... electrolytes
flocculents... polyelectrolytes
How AFM works....
And why do the.....
...because we provide the best
water and air quality.

AFM is...
1. self sterilizing
2. higher surface area for adsorption
3. high negative surface charge to attract APF particles
4. catalytic oxidation reactions
1,000,000 m2 surface area per tonne
catalytic reactions
300 times more than sand or crushed glass
Full independent testing and verification reports are available for AFM in comparison to many crushed glass products

-ve surface
Hexagonal structured water
on surface, prevents biofouling
metal oxide
surface catalysts
Al, Cr, Fe, Mn, La, Ce
as a permanent part
of mesoporous
glass matrix
O & OH
sterilized &
partially oxidized to
on the surface of AFM
-ve electron
+ve, H+ proton
(electron hole)
electron hole
loss of electrons

AFM is
Hardness and Alkalinity
Disinfection by-products
their analysis & activated carbon

Alkalinity is a measure of how much acid is required to drop the pH to 7.0
Sodium bicarbonate & MagPhlow increase alkalinity
Usually referred to as carbonate CO3 alkalinity or bicarbonate HCO3 alkalinity
In reality there may not be any bicarbonate in the water if alkalinity is attributed to OH (hydroxyl ions)
Magnesium oxide

add it to filters or balance tank to increase alkalinity

25Kg last a 100m3 private pool 1 year.

Slow and automatic pH buffer.

Converts CO2 to bicarbonate in water
MagPhlow increase hardness as well as alkalinity

A measure of the alkali earth metal concentration in water Ca & Mg

You can have a high hardness with a low alkalinity

Usually referred to as hadness expressed as Calcium Carbonate CaCO3, but in reality there may be no calcium or carbonate in the water
Hardness & Alkalinity
Sodium bicarbonate...

MagPhlow... to increase hardness and alkalinity, slow steady reaction

DryMag... magnesium chloride to increase hardness, fast... instant reaction
Oxidation of Biofilm
DryOx forms chlorine dioxide when added to water

ClO2 has a lower oxidation demand that hypochlorite, but it is lipd soluble and passes through the alginate layer surrounding bacteria in biofilm.

ClO2 oxidises by electron abstraction as opposed to chlorine substitution reactions of hypochlorite.
DryOx Applications
Spas & Hot tubs... main application
Pools, public & private... treat overflow channel, and pipes once a month. Keeps combined chlorine down
Washing down sides of pool and changing room, bacteria and cryptosporidium control, once a week
Disinfection of inflatables
How to use DryOx
Spas & Hot tubs, add 1 tablet per 1m3

Pools, add 1 x tablet per 20 m3

Wash-down, add 1 tablet to 20 litres
Oxidation of organics and urea by electron abstraction, so no disinfection by-products.

With strong sunlight, everything is oxidised back to carbon dioxide, water and nitrogen gas

ACO in combination wit the rest of DAISY is a complete solution for out-door pools, and pools with UV.
Activated Carbon
May be used to remove residual combined chlorine. Do not use more than 100mm layer
Reduces chlormines to ammonium
Reduces chloro-urea to urea
Absorbs urea
Acts as a perfect substrate to grow bacteria, urease enzymes convert urea to ammonium, nitrifiers convert ammonium to nitrate
Persistent combine chlorine caused by large stable organic molecules, activated carbon removes them.
Dryden Aqua Integrated System
Dolphin friendly
Baby safe
Healthy pools
Size flow @ 0.3bar flow @ 0.5bar flow @ 1bar
DN m3/hr m3/hr m3/hr

40 6 8 15
50 10 14 20
65 20 30 45
80 36 50 75
100 60 80 120
150 90 120 180
200 130 170 250
250 200 240 350
300 280 320 460
350 340 380 550
400 430 490 700

What goes into a filter must come back out in the back-wash.

If this does not happen the filter will fail.

AFM removes 30% more from the water than new sand.

After 6 months AFM is twice as good as sand
IFTS (Institut de la Filtration et des Techniques Séparatives)

IFTS is recognised as the leading independent accredited laboratory in Europe on water filtration media. The Director General, Mr. Vincent Edery of IFTS visited Dryden Aqua’s laboratory and AFM® production facility in December 2013, and he commented on Dryden Aqua's AFM® said: "The visit to Dryden Aqua is exactly what we hope to find in a company that invests so heavily in R&D. They opened a new 40,000 tonne processing facility and have a mature and stable product, which is out performing sand, and other all glass media tested. I have been struck by the depth of scientific knowledge within the firm and their mission to push the boundaries to discover the potential of Activated Glass as a molecular sieve for water filtration."
AFM is confirmed to be the best mechanical filter media in Europe
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