Current Trends in Water Treatment

Physical Activity and
Leisure Management Ltd
POOL PLANT OPERATIONS
INFORMATION UPDATE SEMINAR
(on-line option)

Physical Activity and
Leisure Management Ltd
Carlton Associates Ltd (c) 2013
MODULE 4:
Current trends in Water Treatment

This module re-enforces the
recommended pH values, as well as
Free Chlorine levels for the various
disinfectants that we use. The reasons
for these values are explained.
The chemical process of disinfection is
also covered, here, together with the
more commonly used chemicals, and our
innovative ‘traffic light water test
guidelines!’
In this Module we will be focusing on:

• Revision of the Essentials
• Protecting Swimmers from Themselves
• Harmful Organisms found in Swimming
Pools
• Preventative Measures
• Surface Biofilms
• The Balance Tank

• New Guidelines on pH Correction
• The effect of pH on Chlorine Chemistry
• Free Chlorine levels and Combined
Chlorine Levels
• Popular Treatments
• How does it all Work?
• Organic Chloramines

Let’s start by considering
how much have we forgotten?
 The names of chemicals that we use?
 Why we have target readings?
 COSHH documents?
 When we should test, and why?
 Backwash? What happens?

PROTECTING SWIMMERS FROM THEMSELVES
The lack of high personal hygiene standards
means that:-
• Pollution levels are high
• Risks are greater
• The use of man-made chemicals are
high
• Costs are unnecessarily high

PROTECTING SWIMMERS FROM THEMSELVES
• But if we can’t do anything to change this, then
we must be aware of the consequences.
• Poor standards of pre-swim hygiene, means
that we use more man-made chemicals.
• The pool can become a ‘chemical soup’, if we’re
not careful!
• WE SHOULD BE REDUCING THE AMOUNT OF
MAN-MADE CHEMICALS THAT WE MAKE
PEOPLE SWIM IN !

Some of the other harmful organisms that can be
found in swimming pools, include:-
Pseudomonas Aeruginosas
This is a parasitic virus that can be passed from
human to human, in water.
Its symptoms range from a mild ear ache or
infection, respiratory difficulties, or to a very
distressing rash that can affect any part of the
body.
It is easily destroyed by good disinfection, and so
its presence indicates „poor‟ disinfection.
It is also one of the prescribed tests of a
microbiological analysis.

10
Legionella Virus
This is a virus that is transmitted in water
vapour, and sprays.
The effect is to the respiratory system, and
can prove to be fatal in certain
circumstances.
The virus itself, enjoys conditions between
20 C and 60 C , in stored water areas.
These include circulation dead-
legs, standing water, etc. such as showers;
spas; air-conditioning units; etc.

PREVENTATIVE MEASURES
 Stored water to be kept at 60 C, or
above.
 Regular flushing of domestic hot water
systems, and air-conditioning units (twice
per annum).
 Daily running of showers and wash-basin
taps prior to opening, especially in
facilities that are seldom used.

1212
SURFACE BIOFILMS !!!!!
• The build up of greases and surface film on
vinyls, plastics, rubber, etc
• Warmed water encourages bacteriological
growth.
• Surface biofilms are the combination of both!
• Biofilms need to be cleaned off.
• How will you clean and disinfect
inflatables; floats; pool covers; hose-
pipes; etc., etc

13
THE BALANCE TANK
 In deck-level
pools, the water
flows into a
Balance Tank,
before it flows into
the rest of the
system.
 It is there to
‘balance’ the level
of water in the
pool!
This is a ‘bio-film’ which forms on surfaces, and can house bacteria!
CLEANING !!

14
PH CORRECTION: NEW GUIDELINES
 For disinfectants to work properly, the pH value of the
pool water is critical. It is recommended that the pH
value should be maintained between 7.2 – 7.6 (7.0
to 7.6 in Spa Pools) as disinfection will be more
effective (as may be coagulation)
Target pH should be set at 7.2-7.4
as this allows the disinfectant to
work more effectively.
 Dosing with an acid stabiliser is normally required
with alkaline disinfectants to maintain the correct pH
value.

15
THE EFFECT OF PH ON CHLORINE CHEMISTRY

FREE CHLORINE LEVEL
 To achieve the best possible water quality, it is
recommended that the free chlorine residual should be
at the lowest level that gives satisfactory
microbiological quality.
 This should be possible at less than 1mg/l to an
absolute minimum of 0.5mg/l with a pH of 7.2 to
7.4, provided everything about the design and
operation of the pool is in line with the
recommendations in this manual and the Pool
Water Guide.
 But, your target levels must have come from a Risk
Assessment.

COMBINED CHLORINE
 The combined chlorine residual should be as low as
possible, less than the free chlorine level, ideally
half or less.
 Pools that do not operate to an optimum design may
need to have higher residuals
 Pools that occasionally have large influxes of extra
bathers, or have bathers with specific needs, may
have to meet this extra demand with higher levels of
disinfection.

Most common/popular treatments
Disinfectants Stabilisers
 Sodium Hypochlorite
 Calcium Hypochlorite
 BCDMH (Bromine)
 Chlorine Gas
 Chlorinated
IsoCyanurates
 Sodium Bisulphate
 Hydrochloric Acid
 Carbon Dioxide
 Sodium Carbonate

Which are acids, and which are Alkalis?
Disinfectants Stabilisers
 Sodium Hypochlorite
(Alkali - Liquid)
 Calcium Hypochlorite
(Alkali - Liquid)
 BCDMH (Bromine)
(Acidic - Solid)
 Chlorine Gas
(Acidic - Gas)
 Chlorinated
IsoCyanurates
(Acidic - Solid)
 Sodium Bisulphate
(Acidic - Solid)
 Hydrochloric Acid
(Acidic - Liquid)
 Carbon Dioxide
(Acidic - Gas)
 Sodium Carbonate
(Alkali - Solid)

How does it all work, then?
 When Chlorine (hypochlorites) are mixed with
water, they form HYPOCHLOROUS ACID
(Hypobromous Acid if you use BCDMH)
 The Hypochlorous Acid reacts with Ammonia
(pollution), to form MONO-CHLORAMINES.
These are not harmful, but don’t neutralise
bacteria either.
 Further addition of Hypochlorous Acid to the
mono-chloramines produces DI-
CHLORAMINES.
 It is the Di-Chloramines which we also refer to
as COMBINED CHLORINE, because it is this
element that reacts with the pollution.

How does it all work, then?
 When Chlorine (hypochlorites) are mixed with
water, they form HYPOCHLOROUS ACID
(Hypobromous Acid if you use BCDMH)
 The Hypochlorous Acid reacts with Ammonia
(pollution), to form MONO-CHLORAMINES.
These are not harmful, but don’t neutralise
bacteria either.
 Further addition of Hypochlorous Acid to the
mono-chloramines produces DI-CHLORAMINES.
 It is the Di-Chloramines which we also refer to
as COMBINED CHLORINE, because it is this
element that reacts with the pollution.

QUESTION:
WHY IS THERE ALWAYS A “COMBINED
CHLORINE” READING FIRST THING IN THE
MORNING, IF THE CHEMICAL TREATMENT,
CIRCULATION AND FILTRATION SYSTEMS HAVE
BEEN OPERATING PROPERLY ALL NIGHT?
ANSWER:
Because there is something called
“ORGANIC CHLORAMINES” in pool
water nearly all the time.
23

24
ORGANIC CHLORAMINES
 As well as reacting with ammonia, chlorine
reacts with organic, nitrogen compounds that
mainly come from proteins in bather pollution.
 The resulting chlorinated organic amines
(PROTEINS) are not removed by filtration or
by chlorination, and are shown as part of the
combined chlorine readings.
 Only dilution will significantly reduce the level
unless ultra violet irradiation, or ozone and
carbon filtration is used to treat the pool water.

That is the end of Module 4
What you need to do now:
1. Return to the course page
2. Download the module update notes and save them
on your computer
3. Read through the notes
4. Print out the notes and insert them in your manual

End of Module 4 Presentation

Current Trends in Water Treatment

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Ähnlich wie Current Trends in Water Treatment

Ähnlich wie Current Trends in Water Treatment (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Current Trends in Water Treatment