AODA Work Sheet Exams (1)[1]

7/30/2019 AODA Work Sheet Exams (1)[1]

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Aquatic Operation and Development Australasia

POOL OPERATOR'S CERTIFICATE COURSE

WORKSHEET 1

Filtration

1. . What are the basic aims of Swimming Pool Water Treatment and what are the three basicfunctions that must occur to achieve them?

To disinfect the water in order to prevent the spread of infects and other diseases

Prevent irritation to the eyes and mucous membranes

Eliminate odors and obnoxious tastes

Prevent algae growth

Keep the water clear, sparkling and attractive

Prevent corrosion to plant and equipment

Prevent lime scale formation

Three functions

Circulation, filtration, disinfection.

2. . Explain the principle of an open gravity filter and a pressure filter (use diagrams)

See figure 1a and b

Sand Filter

The filter is placed abouve the pool. After the water has passed through the lint strainer the water is

dispensed over the filter bed. The water moved through the filter by gravity and as it passes through

all of the pollution is caught on the sand/dirt. The amount of dirt held in the filter slowly increases

and at the same time the height of the water in the filter increases creating greater weight andpressure to push through the sand. After the water passes through the sand it is dispersed in the under

drain system and returned to the pool.

Pressure filters

Similar to a gravity filter but built inside a vessel and operate on the principal of pressure. Pressure

from the pump forces the water through the sand. After which it can be returned to the pool.

3. . What does the term 'Head Loss" mean, in relation to the operation of an open gravity filter?It is a gauge that is fitted to the filter to indicate when a backwash is needed.

4. . What are the advantages and disadvantages that an open gravity filter has compared toother filter designs?

Advantage

Sand and water are easy to see

Easy to get into for maintenance


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Its design provides for almost trouble free operation

Disadvantages

It can take considerably more room than other filters

Depending on its location it may be more expensive to install.

5. . What does the term 'Backwash' refer to in the operation of swimming pool filters?

The reversal and increasing flow rate through the filter to discharge the dirty water to waste.6. . How do we know when a filter is in need of backwashing?

It will need to be backwashed more regularly if it is a small filter, the water is unclear, a lot of

windblown pollution is entering the pool, and if there has been a large bather load.

7. What procedure is followed if a bank of 4 filters require back washing?Isolate one filter at a time and increase the flow rate to around four or five times the filtration rate. The use of

air scouring before reversing the flow helps agitate the filter bed and thus, releases the pollution particles.

Then backwash the system until the water turns clear. Repeat this step for all four filters.

8. What problems may occur in the operation of a filter if it is not correctly backwashed

It will not be able to pass the water through as fast as there will be a lot of pollution already in the

filter.

9. What are the factors that determine how long a filter will efficiently run before it

requires backwashing?

Pool volume

Turnover

Pool water temperature

Bather load

Water balance

Cleaning regime

Location (indoor/outdoor)

Type of filter media

Type of filter.

10. . What is Aluminium Sulphate used for and how is it used in swimming pool watertreatment?

Aluminum sulfate is used to create a floc, which is a molecule made up of lots of tiny

molecules that normally wouldnt be big enough to get caught in a filter and therefore makesthem large enough to be filtered out of the pool.

11. . What problems can be experienced when using Aluminium Sulphate if the pHof the water is not correct?

Aluminum sulfate decreases the total ph of the pool. Therefore, if the ph is already low it will be

decreased further and could possibly take it below regulations.


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12. What does PAC stand for and how does it work?

poly-aluminium chloride. It breaks down colloids and encourages microflocculation. A coagulant

may not be needed. Certainly, if the water is turbid, dull or not sparkling.

13. .What types of sand can be used forswimming pool filters?. 16/30 mesh

14. . Name another formof filtration medium, other than sand that can be used in pool watertreatment?

Diatomaceous earth filter or D.E

15. . Why is it necessary to ensure that some pools have their contents either fully replaced orpartially replaced with clean water?

Generally speaking the pool should not be emptied unless absolutely necessary, due to

potential structural damage. When emptied, the walls and floor can be assessed for cracked,

broken or loose tiles or vinyl and these should be mended or replaced. The surfaces can then

be cleaned with a chlorine-based disinfectant. Acid washing may be necessary to get the tiles

cleanrefer to the manufacturers advice as this can damage the grouting. In either case, thesolution needs to be neutralised then rinsed to waste prior to the pool being refilled.


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WORKSHEET 2

Disinfection

1. . Explain the term 'Breakpoint Chlorination' and how it applies to swimming pool watertreatment. (include diagram)

When chlorine is added to swimming pool water which has been contaminated by bather loading, it

begins to reach with the organic matter and ammonia like compounds present and is gradually usedup. These compounds are introduced by bathers from urine and perspiration and their reaction with

chlorine forms chloramines. When all of the chlorine in the pool exists as chloramines this is termed

combined chlorine. Breakpoint chlorination is when there are no chloramines are present in the

water and all of the chlorine in the pool is available to use. This is seen when the pool tests read that

the total and combined chlorine levels are the same.

2. . What is 'Free Residual' chlorine?Chlorine that is available to react or is free in the water.

3. . What are the symptoms of pool water which is insufficiently disinfected?Murky, low chlorine levels, low pH

4. . Other than free residual chlorine, what level should the total or (combined) content of thepool water be?

No greater than 1mg/l

5. . Why should log sheets be kept and what sort of information should be recorded on them?Log sheets should be kept to ensure that the pool water is within regulations at all times. It is also

important for incase the center is audited or visited by the health department. It is a legal requirement

that log sheets are kept. The log should include, the date and time of the test, water temp, bathingload, pH, free chlorine, total chlorine, combined chlorine, bromine, hydrogen peroxide, alkalinity,

operational remarks, clarity.

6. What two chemicals are used to 'neutralize' the acidity of the swimming pool water when it is

treated with chlorine gas?

Sodium bicarbonate or soda ash

7. . Name some of the pollutants introduced to the swimming pool water by bathers?urine, perspiration, dead skin, hair, mucous, cosmetics and sunscreen lotions

8. .What two main factors cause the loss of free residual chlorine from pool water?

Pollution from both bathers and environmental factors such as heat will cause free chlorine todisappear.

9. . How can free residual chlorine be maintained in a pool?The distance between the inlet and outlet is shorter

The turnover rate is increased

In an outdoor pool deep water screens chlorine from the sun

A stabliser is used to stop the dissipation of free chlorine from the sun


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10. . What equipment is used to introduce gas chlorine to the pool water?Injector

11. . How does Sodium Hypochlorite differ from gas chlorine in the treatment of swimmingpool water?

Chlorine gas: It usually requires dosing with an alkali, such as sodium bicarbonate or soda ash to

maintain pH, as hydrochloric acid is formed when elemental chlorine gas is added to water.

Sodium Hypochlorite: is strongly alkaline and tends to keep high pH levels. It is generally used in

combination with acid or carbon dioxide dosing.

12. . Why do we use Hydrochloric Acid when treating pool water with Sodium Hypochlorite?Because sodium hypochlorite increases the pH and therefore it needs to be lowered by adding an

acid.

13. . What is the 'golden rule' when using pool water chemicals?Add the chemical to the water not the water to the chemical.

14. . Name four disinfection methods used to treat swimming pool/spa water?Chlorine, Bromine, UV and Ozone

15. What are the main characteristics which make chlorine the most popular in treating

swimming pool water?It is a powerful disinfectant

It remains in the water as a residual

It is a strong oxedising agent

It is a strong belaching agent

16. List three types of chlorine?

Liquid, solid and gas chlorine


WORKSHEET 3

Spa Pools / Water Slides / Hydrotherapy Pools

1. . Name the organism responsible for outbreaks of certain skin complaints in spa pools andhot tubs?

Chloramines

2. . What factors contribute to the growth of Pseudomonas in spa and hot tubs?Injury

Spa environments and materials

Skin lesions from recent trauma or immune deficiency3. . What is the name of the skin infection that has been linked to inadequately filtered and

disinfected spa and hot tubs?

Psedomonas aeruginosa

4. . What is the recommended temperature range for a spa and hydrotherapy pool?32 degrees

5. . What are the minimum staff requirements for the operation of a water slide and what are


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their duties?

The minimum staff requirements for a water slide is two people. One for at the top of the

slide and one down the bottom. The person at the top instructs patrons when to go down the

slide and the person down the bottom makes sure the person gets out ok .

6. . A Bather Warning Sign should be displayed in a prominent position at the entrance tothe water slide. List four of the requirements on the notice.

Minimum height to use the slide is 1.1mCan not use if pregnant

Must use the slide in a safe manner

No jewelry or watches to be worn

7. . What is the recommended turnover rate for a water slide?1hr

8. . A Bather Warning Sign should be displayed in the entrance to a spa pool, list fourrequirements listed on the sign.

DO NOT put your head under the water.

DO NOT use the spa while under the influence of drugsor alcohol.DO NOT use the spa for more than 20 minutes at a time.

DO NOT allow children to use the spa unsupervised.

9. Why is it particularly important to replace spa pool water at least once per week?Beacsue it is a requirement that the walls, floor and sourounding surface is cleaned once a week and

to do trhis properly the spa needs to be empty.

10. . Why do outdoor pools generally have a higher degree of water replacement than indoorpools?

Because more water is evaporated by the sun.

11. . Why is it of particular importance that emphasis be placed on the disinfecting of changeroom and toilet floors, as well as pool deck and surrounds?

Because many polutanmts and backeteria can enter the water through feet. Therefore, by keeping the

floors of changerooms and toilet floors and pool deck clean will minimize the amount of pollutants

entering the pool.

12. . What is 'Meningo-Encephalitis? What is the name of the organism responsible for it andhow is it spread in the human body?

It is desieas that can be caught through poorly maintained pool water. The orgsanism responsible for

it is Acthamoeba species and Naegleria floweri. It spreads through the nasal cavity and migrates tothe brain.

13. . Through which medium do bathers release pollutants into swimming pool water?Through albuminoid and nitrogen compounds derived from urine, perspiration, dead skin, hair,

mucous, cosmetics and sunscreen lotions.

14. . What is the approved method of testing water clarity in swimming pools in SA?


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a matt black disc, or a disc that contrasts with the colour of the bottom of the pool, 150 mm in diameter,

is (or would be) clearly visible from above the water at the deepest part of the pool

15. . Why is it important to keep a preventative maintenance program? Draw up a briefmaintenance schedule for a swimming pool, water slide and spa facility

Because it can prevent things from breaking and having to be replaced. It also creates a safe

working environment.

Pool:Check and clean injectors

Check CH, CO2 and acid lines for general wear and tear

Backwash regularly

Check pumps

Recalibrate system

Maintain chemical levels as per regulations

Check for general wear and tear

Clean the probes

Clean the filters

Get 3 quotes from pool maintanence to a regular service and maintanence

Same for Spa

Same for slide plus: conduct regular safety slide checks

16. What is Cryptosporidium and what methods are used to minimize the likelihood of an

outbreak in bathing water.

Crypto is a Gastro-Intestinal Infections. Pool users suspected of being infected with eitherCryptosporidium or Giardia are advised to avoid attending a pool for one month after symptoms

cease. As the recommended maintenance level for disinfectant is less than 8 ppm, the pool must

remain closed until water samples prove no evidence of the microorganism. If a pool is closed due to

suspected contamination by Cryptosporidium, signage is advisable to warn infected persons not tovisit or potentially contaminate other pools.

Patrons who have suffered a gastrointestinal illness or diarrhoea should be advised not to use the

pool until at least one week after symptoms cease.


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WORKSHEET 4

Circulation/pH Control

1. . Define the term 'circulation' and how does it apply to the operation of a swimming pool?(include diagram)

The process whereby water is moved or propelled through a series of pipes within a given turnover

period.

2. . What type of pump is commonly used in pool water circulation and how does it work?(diagram)

A centrifugal pump

See figure 2a

Uses centrifugal force to accomplish a pumping action. Each pump ios eqqiped with an

impeller or wheel with curved blades. Water to be pumped enters at the center of the

impeller and due to the high rotating speed is discharged by centrifugal force at a high

velocity. The energy contained in the water at this point as velocity is converted to pressure

by passing the water through an area of increasing cross section in the form of a volute case

or diffuser. The resistance to the water flow in a circulation system is caused by friction ofwater in the pipes, elbows and bends in the pipe, blockages due to dirty filters and the

necessity to lift the water upwards at some point in the system.

3. . In pool water circulation, what does the 'turn-over rate' mean, and what should the turnoverrate be for a swimming pool?

The time it takes to circulate through the filters a quantity of water contained in the pool. The


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turnover rate for a main pool is 6hours

4. . Why do shallow pools generally have a higher turnover rate than deep pools?Greater loading and therefore more pollution therefore, needs to be cleaned mpore

frequently.

5. . In a modern well-designed pool, how is the water collected, distributed and returned in theoperation of the water treatment system?

Water is introduced to the pool via small inlet orifices which are spaced at intervals on the bottom of

the pool, for its entire length. This design enables the water entering the pool, to mix evenly. The

water is the collected in the overflow channels running the full length of each side of the pool. As

water enters these channels a weir effect, is created which draws the water over the edges of the

channels thus, pulling pollution and debris into them. Water is then returned to the plant room so it

can be filtered, disinfected and treated. There are many designs that return the water to the pool but

in all cases a lint strainer should be placed before the pump to protect it from damage. There should

also be isolating valves that can be operated in the case of a breakdown.

6. . What is the function of a 'balance tank' in a large public pool?

The balance tank stores the water that is displaced during large loading periods.

7. . Pools that don't have balance tanks may be disadvantaged in what way?When there is large loading in the pool it will overflow. Without a balance tank the overflow

channels wont work properly.

8. . Explain the term 'consecutive dilution' and how it applies to the operation of watertreatment in swimming pools.

The amount of turnovers required to remove the pollution from the pool. It emables the

operator to see how clean the pool is.

9. . Draw a diagram showing the preferred method for water distribution in a pool.

See figure 2b

10. . What does the term pH refer to in water treatment?The measure of activity of alkali in pool water

11. . What is the range of the pH scale?0-14

12. .What effect does pH have on bather comfort?Too high or low pH will cause eye irritation

13. . What two acids are commonly used in water treatment to lower the pH?Hydrochloric acid and carbon dioxide

14. . What is Sodium Bicarbonate's main use in water treatment?To create reserve alkalinity


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15. Explain, using a few sentences for each, the following terms : Reserve AlkalinitypH control, Scale and Corrosion

reserve alkalinity: sodium carbonate that is added that doesn not affect the pH but increases the total

alkalinity.

pH controle: the ability to increase or decrease the pH of the pool to create an optiumum pH

Scale:formation of build up of certain compounds, usually calcium on wetted surfaces in water

overloaded with these compounds and lacking hytdrogen ions leaves them behind.

Corrosion: deterioration at the surface of metal caused by chemical reaction in which water

aggressive of certain compounds takes away the etal in a solvent like action.

16. . According to the 'Public and Environmental Health Act' what should the pH range ofpublic swimming, spa and hydrotherapy pools be?

7.2 and 7.6

POOL OPERATORS CERTIFICATE COURSE

WORKSHEET 5

Bromine / Ultraviolet Light /Algae

BROMINE1. What do hypobromous and hypobromite ions depend on in relation to their

relative concentration strength.

pH

2. What part of the Bromine equation acts as the disinfectant?

The hydrobromus acid or the product of the reaction

3. Name the 2 methods used to produce hypobromous acid. (Brief explanation)

BCDMH added to pool water, in tablet or granular form.

Sodium bromide with sodium hypochlorite, reacted with hypochlorus acid Creates

hydrobromus acid

4. Give a brief explanation of Bromamines and their source.

Combination of ammonia and organic nitrogen. It is used an a disinfectant

ULTRAVIOLET RADIATION

1. .What are the 2 classes of Ultraviolet light?Natural and artificial

2. . How does Ultraviolet work in the treatment of swimming pool water?It is believed it occurs as a result of the molecular rearrangement in DAN and RNA, organism

building blocks so to speak. This appeasrs to block their replication.

3. . What is the most widely used method of treatment?Teflon tube design

4. . Give a brief explanation on how this method works.Water is passed through a series of Teflon coated tubes. On the outside pf the tubes are a

bank of mercuary lamps, sufficient in wattage to to emit the desired dosage.

5. . What new innovations in Ultraviolet design technology have been made since the CabinetLamp system and what are their advantages?


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The ultraviolet light plus hydrogen peroxide (UV+H2O2) system is approved for disinfecting indoor

swimmingpools up to 500,000 litres in capacity.

Disinfection occurs when water is passed through the ultraviolet unit. As no residual is produced

there is no antimicrobialaction in other parts of the system. Therefore, in order to achieve a residual oxidising and microbial

capability, hydrogen peroxide must be used in conjunction with ultraviolet light.

Hydrogen peroxide is a powerful oxidising agent and in its concentrated form it is a clear liquid with

a sharpodour. It provides a residual capacity to oxidise organic material derived from bather load and other

sources in

the pool water; thus inhibiting micro-organism growth within the remainder of the system. For theultraviolet

light plus hydrogen peroxide system to be effective it must operate 24 hours a day.

ALGAE

1. .What is Algae?

Free flating microscopic plant and animals known as plankton2. .What is an Algistat and Algaecide?

Algisat: a chemical used to prevent algae growth

Algecide: a chemical used to kill algae

3. .What is Copper Sulphate used for in swimming pool water treatment?It is a algicide used to kill algae

4. .What precautions should we take when using Copper Sulphate ?The coumpunds may discolour bathers and turn hair green

5. .What 3 elements are responsible for the growth of Algae?

Sunlight, warm weather, low chlorine risiduals

6. . What is the best method of ensuring an Algae free pool?

At the close of season increase the pH to 8.3 to lower the level of dissolved co2

alternatively, covering the pool will eloiminate the sunlight necicary for growth.

AODA Work Sheet Exams (1)[1]

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