Swimming pools Flashcards
What are the main swimming pool pollutants?
Surface e.g. hair, dust, secretions from nose/throat/skin etc
Insoluble e.g. sand from filters, detritus
Dissolved e.g. urine, sweat, cosmetics
Chemical e.g. reactions in treatment
Bacteria/Fungi e.g. athletes foot, ring worm, conjunctivitis
Where is the highest percentage of bacterial loading in a pool and what percentage?
Top 16cm of pool water contains 75% of bacterial load
Where is insoluble pollutants most likely found?
Many of the insoluble pollutants may settle to the bottom of the pool
What are the typical phases in a swimming pool purification plant?
Usual methods employ recirculation involving:
chlorination
filtration
aeration
And the regular addition of fresh water.
What is meant by the term “pool turnover” and how many cycles will an average good system take to filter 99% of the water?
The number of hours it takes to pass the total pool volume through the filter.
In a pool with good turnover, it is estimated to take 7 turnovers to filter 99% of the water.
Turnover system times are largely determined by the use of the pool, what are the acceptable periods for, private outdoor, private indoor and school pools?
Private outdoor pool (UK) – 8hr turnover if small bathing load
Private indoor heated pool (UK) – 6hr turnover
School pools – heavily used, require 2hr
turnover
What does DPD stand for and what is the function of DPD 1, 2, 3 & 4?
Diethyl-p-phenylene diamine
DPD #1 tablet shows the level of Free Available Chlorine (NB: Levels above 10 ppm can ‘bleach out’ the sample)
DPD #2 tablet is used to estimate the monochloramine and dichloramine fraction of the Combined Available Chlorine
DPD #3 tablet measures the level of Combined Available Chlorine (that has reacted with impurities in the water)
DPD #4 tablet is used to measure Total Available Chlorine in the water.
What form of chlorination technique is used in swimming pools?
Breakpoint Chlorination
What is free available chlorine?
Free Available Chlorine (FAC): Is the amount of chlorine in the pool that has not reacted with foreign substances other than water.
How does chlorine create chloramines?
When chlorine is added to a polluted pool, it combines with pollution and oxidation commences to form chloramines.
What is combined available chlorine?
Combined Available Chlorine (CAC): Is basically “used” chlorine, that has reacted with foreign substances other than water and is no longer available in its free state (i.e. to disinfect the water)
What is total available chlorine?
Total Available Chlorine (TAC): Is the concentration of both free and combined chlorine together.
What residual level of free available chlorine should be maintained? The level of combined available chlorine should be kept to a minimum, what level or below should this be?
Free available chlorine residual should be maintained between 1ppm and 3ppm (2ppm is optimum)
Combined available chlorine should be kept to a minimum - preferably below 0.2ppm.
Algae is a problem within pools, what product is used to control this and what are the negative effects of its presence?
Algicides should be added to control algal growth and protect the water from being stripped of chlorine.
Grow rapidly, increase chlorine demand, block filters, discolour the water
What should be considerations for pool floor surrounds?
Non-slip surface
Edges sloping away from pool
Hard and impervious
Level walkways
Kept clean and well maintained
Drains provided.
