Active IQ Level 2 Award in Pool Operations (sample manual)

Manual
Level 2 Award in
Pool Operations
Version AIQ005806

The principles and practice
of pool water treatment
and testing
Aim
This unit provides an overview of the responsibilities held by pool operators to ensure the environment is safe for
staff and visitors. The different types of pool that operators may come across are discussed, along with the various
models of pool ownership and recommended temperatures for these different types. An understanding of the
importance of good cleanliness and hygiene is essential for a pool operator, as well as knowing the causes of water
pollution and how a pool’s water circulation system works to keep that pollution to a minimum.
A key responsibility of pool operators is that they know how to test pool water, and so a further focus of this unit
is the tests used to ensure optimum pool water quality, how to carry out the tests properly, and to understand the
importance of accurate record keeping.
Learning outcomes
At the end of this unit you will:
• Understand the legal responsibilities of pool operators to provide a safe pool environment
• Understand the types of pools and pool ownership
• Understand the causes of pool water pollution and contamination
• Understand the importance of good bather hygiene prior to the use of pools
• Understand the importance of good standards of cleanliness in the swimming pool environment
• Understand the operating principles of a simple pool water circulation system
• Know the recommended temperatures for the types of pools used in active leisure facilities
• Understand how pool operators provide a safe pool environment
• Know the essential tests to ensure optimum pool water quality
• Understand the different types of pool water testing equipment
needed to ensure good quality pool water
• Demonstrate correct pool water testing techniques
• Understand the importance of accurate record keeping
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1

Different types of pools and pool ownership
Section 2
Section 2: Different types of
pools and pool ownership
The range of pools used within the active leisure sector includes:
• Competition pools
• Leisure pools (incorporating water features)
• Outdoor pools
• Diving pits
• Shallow water pools
• Spa pools
• Hydrotherapy pools
• Interactive water features
The main purposes of the pools used in the active leisure sector are summarised in table 2.1.
Type of pool
Purpose/description
Swimming pools • Competitive swimming and diving
Recreational swimming pools and conventional main
pools
• Fitness swimming
• Training
• Recreation
• Adult teaching
Leisure pools • Enjoyment
• Water-based play
Pools operating at slightly higher temperatures • Children’s teaching
• Used by babies, young children and those with
a disability
Hydrotherapy pools • Found in schools, hospitals and hospices
Spa pools • Relaxation
• Aquatic therapy, physiotherapy, etc
• These pools operate at higher temperatures
than other pools
• Found in many locations, including hotels and
fitness clubs
Hot tubs • Domestic spa pools used for relaxation
• Often found in holiday and lodge parks
Counter-current/exercise pools • Small pools with a mechanically derived current
against which users can swim
Birthing pools • Small pools in which women can choose to
give birth
• Subject to strong bacteriological control
Hotel pools • Used by hotel guests and club members
Paddling pools • Outdoor paddling pools of shallow water
Plunge pools • Used for cooling down after exercise
School pools • Often smaller pools used for swimming lessons
• Sometimes used by community and other groups
at evenings and weekends
The principles and practice of pool water treatment and testing
Table 2.1 Main types of pool and their purposes
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Pool water pollution
Section 3
Section 3: Pool water pollution
It is important that the pool operator understands the causes of pool water pollution and contamination, and the
role that the plant plays in dealing with or removing them. The causes of pool water pollution can be separated into
three categories:
• Physical pollutants
• Chemical pollutants
• Biological pollutants
The common denominator for all these forms of pollution is the bathers themselves.
Pollution added by bathers
Bathers introduce all three types of pollution to the pool water: physical, chemical and biological. Each day, an
adult produces 1 litre of sweat, 1 billion skin fl akes and 38g of grease (SPW). It is also estimated that each bather
releases approximately 30ml of urine and 200mg of urea in a typical swim session. When a bather is exercising,
they also release a signifi cant amount of sweat; this increases in line with pool water temperature.
In addition, the human body carries numerous chemicals in the form of cosmetics, deodorants, powders, creams,
lotions, oils, etc, all of which add further pollution to the water.
Outdoor pools
Outdoor pools, especially those found in warm climates, experience signifi cant problems caused by suntan lotion
and sweat added by the bathers, as well as environmental pollution from sand, leaves, grass, soil, etc.
Types of pollution
The types of pollution can be further classifi ed as:
• Surface pollution
• Dissolved pollution
• Suspended pollution
• Insoluble pollution
They can be found in various places in the pool itself (as illustrated in fi gure 3.1).
Dissolved pollution
Surface pollution
The principles and practice of pool water treatment and testing
Suspended pollution
Insoluble pollution
Figure 3.1 Pollution distribution
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Section 4
The importance of good bather hygiene prior to pool use
Point 1: Changing room floors must be kept clean
by regular scrubbing and mopping.
Point 2: Bathers should be encouraged to use the
toilets prior to swimming.
Point 3: All bathers must be encouraged to
shower prior to swimming in order to remove
bacteria, sweat, cosmetics, etc.
Point 4: Avoid poolside contamination by
encouraging the use of overshoes. Pool surrounds
should be thoroughly scrubbed.
Figure 4.1 The four-point plan for good pool hygiene
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The pool water circulation system
Section 6
Section 6: The pool water
circulation system
In order for swimming pool water to stay safe and clear, it needs to flow through a series of processes (see figure 6.1).
Figure 6.1 Schematic pool circulation (hypochlorite disinfectant: no UV)
ACID INJECTION
POINT
POOL
BALANCE
TANK
HEAT EXCHANGER
(CALORIFIER)
SIGHT GLASS
TO DRAIN
HYPOCHLORITE INJECTION
POINT
FILTER
FILTER
TO DRAIN
COAGULANT/
FLOCCULANT
INJECTION
POINT
BACK WASH
FLOW METER
SIGHT GLASS
STRAINER
CIRCULATING
PUMPS
SAMPLE POINT
TO DOSING UNIT
A surface draw-off system removes the surface water, and
water leaves the bottom of the pool through sump outlets.
In deck level pools, the water is then fed into a balance tank.
The balance tank (figure 6.2) accommodates the water
displaced by bathers. The balance tank also provides
a means of introducing water into the system to replace
water used to wash the filters.
The principles and practice of pool water treatment and testing
Figure 6.2 A balance tank
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Section 9
The essential tests to ensure optimum pool water quality
The comparator
The traditional method of pool water testing for pH and chlorine uses a comparator. This is a very simple piece
of equipment where the test sample containing the reagent dye is compared against a circular disc of different
coloured pieces of glass.
Ideally, the comparator should be fitted with a portable back-light which provides good quality white light to
accentuate the colours, or it should be viewed against a bench-mounted white light source.
Figure 9.2 A comparator
The comparator should be used with the disc appropriate to the test being carried out: a pH disc (phenol red), a
chlorine disc or a disc which measures bromine levels.
If the comparator is viewed against a white light source, a more accurate result will be given.
Figure 9.3 Chlorine, pH and bromine discs
Using a comparator to measure pH
1
Select
2
Add
3
Take
4
Insert
5
Revolve
the phenol red disc and insert it into the comparator. Ensure it is installed the correct
way, with the numbers in the right hand corner of the comparator.
a 10ml sample of water to the left hand test tube.
a second clean test tube containing 10ml of water and crush a phenol red tablet into it.
the test tube containing the phenol red dye into the right hand side of the comparator.
the comparator disc until the colours match. The reading can be found in the bottom
right hand window of the comparator.
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Section 9
The essential tests to ensure optimum pool water quality
Typical procedure
1 Switch the photometer on using the on/off key.
2
Select the appropriate mode (e.g. free chlorine or pH) by pressing the mode key or the appropriate button
on the keypad.
3
4
5
Fill a clean test cell with 10ml of test water, aligning the triangles on the test tube with those on the
photometer, and press the zero/test key.
Add the appropriate reagent tablet (e.g. phenol red to measure pH).
Crush the tablet and make sure it has properly dissolved; screw the cap back on.
6 Place the test cell in the test compartment, once again aligning the triangles, and press the zero/test key.
7
8
The method symbol will then flash and the result will appear in the display panel.
Remember to repeat the zeroing process in between each test.
A photometer will only measure within its individual range, so if the sample is either below or above this range, an
error message will be generated. If it is above range, it will be necessary to carry out dilution of the sample until the
sample comes back within the range of the instrument.
When measuring chlorine levels using a photometer, the principle of dissolving the DPD 1 into two drops of water
and then making it up to 10ml should also be followed, and it is still necessary for the operator to leave two minutes
for the chemical reaction to take place between the DPD 1 and DPD 3 in order to establish the total chlorine reading
from which the combined chlorine level is derived.
Newer photometers have a built-in timer which will count down
from two minutes when the operator indicates that they are
working out a total chlorine reading.
Where the water has a high calcium content, it may be
necessary to use DPD 1 high calcium tablets.
Photometers are precision instruments but they must be
checked against calibration standards to ensure that they are
properly calibrated. Some photometers have to be returned
to the manufacturer for recalibration, whereas others can be
recalibrated by the user.
Cyanuric acid test
Figure 9.6 Calibration standards
If the pool is treated with ‘stabilised chlorine’ (i.e. chlorine that contains cyanuric acid, e.g. trichlor), it is also
necessary for the cyanuric acid levels to be tested on a weekly basis. Most photometers will measure cyanuric acid
levels; the typical procedure is followed, except that a cyanuric acid test reagent tablet is used. The recommended
range for cyanuric acid is between 50 and 100mg/l. If the pool operator does not use a photometer, it is still
possible to measure cyanuric acid levels using the turbidity test method.
The turbidity tester consists of two plastic tubes: an inner tube, which is graduated, and an outer tube, which has a
water level indicator. A cyanuric acid tablet is dissolved in the sample, and if there is any cyanuric acid present, the
sample goes cloudy. The inner tube is then pushed into the outer tube until a black spot on the bottom of the inner
tube disappears. At this point, the reading on the inner tube at the interface with the water is noted, and from this
the cyanuric acid level can be determined.
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