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Water quality 2


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What guidelines are used to determine e coli levels for beaches?
Ontario Beach Management Protocol
Ontario Beach Management Protocol requires the posting of beaches as unsafe for swimming if the level of E.coli exceeds what value?
100 per 100ml of water
Which organism is routinely tested in recreational water quality?
E. coli
Name 5 organisms that may pose a health hazard other than e coli recreational water.
Aeromonas spp., Pseudomonas
aeruginosa, Staphylococcus aureus, Shigella spp., Salmonella spp.,
Campylobacter spp., Giardia spp.,
Describe the recirculation system of a swimming pool.
Water is removed from the poolthrough two main drainage systems.
a. Some water is removed through the main drain
and some water is taken from the surface of the pool
through the overflow system consisting of skimmers.

After removal, the water flows through a pipe
to a strainer or screen where hair and lint is removed.

Having been strained of debris, the water then flows to the filter plant for the removal of fine-particles such as dust, body oils, algae, slime, bacteria, coagulated material,
etc. This filtration aids the chemical disinfection
and oxidation processes which beneficially take place
after the water is returned to the pool. Pool filtration
is achieved most commonly by particle entrapment
in either (1) a bed of sand or (2) a thin cake of
diatomaceous earth.

As the pool water flows beyond the filters it is chemically
treated. Chlorine disinfecting agent is added, pH
adjustment chemicals are introduced, and the treated
water is returned to the pool to destroy bacteria and
oxidize other undesirable solids.

Water is re-entered into the pool through an inlet.
What are trihalomethanes?
Trihalomethanes (THMs) are a byproduct of the water treatment process.
What is the public health risk associated with trihalomethanes?
Cancer producing
How are trihalomethanes formed?
hey are formed when natural organic material, such as the decaying vegetation commonly found in lakes and reservoirs, reacts with chlorine used to treat the water.
What is the most common trihalomethane?
List 3 types of filtration used in community water supplies?
Diatomaceous earth

Sand filter

Activated carbon
Under what conditions do you issue a boiled water advisory?
1. When bacteria or parasites have been found in the water.

2. Lack of disinfection.

3. Following the outbreak of illness in the community linked to drinking water.
What regulations are used to issue a boiled water advisory?
Ontario Drinking Water Standards.
Name a bacterial, parasitic and viral source of contamination for water.
Bacterial: Salmonella typhii.

Viral: hepatitis

Parasitic: Cryptosporidium parvum oocysts and Giardia lamblia cysts.
What causes the rotten egg smell in drinking water and how is it treated?
Hydrogen Sulphide is a gas by-product of decaying organic matter and sulphate reducing bacteria. Treatment methods generally involve oxidation followed by filtration. Oxidation processes range from chemical treatment (usually chlorine or hydrogen peroxide), ozonation, glauconite greensand or aeration.
What causes the light yellow colour in drinking water?
Yellow/brown colour is caused by humic substances. Also, water main repairs, construction and other maintenance work in your area can cause some rust and scale products.
Samples of are free of coliform but have a green pigment what does this mean?
Presense of pseudomonas.
How do you clean a hot tub that is positive for pseudomonas?
Drain the spa and refill just above the jets.

Remove the filter and soak in a solution of chlorine and water during treatment. (2 Tbsp of Chlorine/5 gallons of water)

Shock with four times the normal dose of Stabilized Chlorinating Granules.

Turn on the jets and circulate for 2 - 3 hours. The bacterial growth usually builds up in the lines, so it is necessary to flush them thoroughly.

Drain the spa again and refill with fresh water.

Chemically clean (such as SpaGuard® Filter Cleaner®) and / or replace the filter .

Rebalance spa and shock. Do not enter spa until sanitizer level drops below 4.0 ppm.
How often should you backwash the sand filter?
2/month or if pressure reaches above specified manufacturing level.
Why should you backwash your filter?
Build up in pressure may burn out pump.
After swimming in a lake person has what looks like inflamed mosquito bites. What do you suspect?
Swimmers itch. Caused By The Penetration Of The Larval Stage Of Certain Flatworms. It Is Neither Dangerous Nor Contagious,
Activated Carbon (AC) Water Filters
Effective in removing organic contaminants from water, will also remove chlorine. AC filtration does not remove microbes, sodium, nitrates, fluoride, and hardness.
Ultraviolet (UV) Water Filters
Generally kills 99.9% of bacteria and viruses. Doesn't remove the dead cells and won't remove other contaminents
Reverse Osmosis
Removes substances that would otherwise cause the water supply to be unhealthy or unappealing, for instance foul tastes, smells or colours.
Sand Filters
Removes most bacteria, and turbity.
A local farmer phones your office and tells you that a chemical analysis of his well water indicates a nitrate concentration of 30 ppm. Should he be concerned?
The presence of nitrate in a water analysis is a danger signal. Nitrate is an indication that your water supply may be contaminated with bacteria.

Sources of nitrate in groundwater include decaying plant or animal material, agricultural fertilizers, manure, domestic sewage and geological formations. Higher nitrate concentrations are frequently found in shallow wells in rural communities with intense fertilization and farm crop production.

Large amounts of nitrate are dangerous to infants. Babies drinking high nitrate water develop a blue color of skin because the blood has a decreased ability to carry oxygen. Continued drinking of the water will cause the baby to become ill, or may even result in death.

Partial removal of nitrate can be accomplished by reverse osmosis. Complete removal of nitrate may be accomplished by deionization treatment.
E. coli at a beach exceed 100/100 ml

Beach Management Protocols
In accordance to the Mandatory Health Programs and Services Guidelines.
Campground water question - recieved an O/G result, what do you advise the operator?
The test was overgrown with non-coliform bacteria making the coliform result unclear
Your water is unsafe for drinking unless boiled

Restore disinfection, notify users and issue a boiled water advisory.

U.V and filtration
At 4:05 pm on a Friday you get a call from a water treatment plant operator of a small municipal system. The operator informs you that the chlorinator has malfunctioned and there has been no chlorine going out into the distribution system for approximate
Is it back online?
If it is back online then have the water tested, sample and test.

If not back online then issue a boiled water advisory
Water quality parameters?
Suspended solids
How do you disinfect a well?
-450 L add 455 mls of chlorine
-open taps until smell chlorine
-do not let the water enter the septic system.
-let stand 12 hours
-test 48 hours later
-test 1 week later
What are the aethetic objectives?
AOs are established for parameters that may impair the taste, odour or colour of water or which may interfere with good water quality control practices. For certain parameters, both aesthetic objectives and health-related MACs have been derived.

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