Safe Water Flashcards
What does the presence of Pseudomonas Aeruginosa in a hot tub indicate?
What is the public health concern, what actions should be taken, and why?
This indicates a problem with the cleaning and disinfection of the hot tub.
Pseudomonas aeruginosa is a bacterium that causes eye, ear, and skin infections (hot tub rash) to those that come into contact with it.
It thrives in biofilm, which can easily accumulate in hot tubs. water sanitizer (Cl/Br) levels in hot tubs are also hard to maintain, making it easy for bacteria to survive.
close the spa to bathers, order the operator to drain, clean, and sanitize the tub and the circulation system, then to refill, and balance the chemistry before reopening.
What is the purpose of a GFCI when used with underwater lights?
To act as a fail-safe measure that cuts power in the event that current is leaking from the circuit (lights) into the pool.
What is a cross connection in plumbing? give an example, and explain PH significance.
A cross connection is anywhere that potable water supply comes into contact with non-potable water. examples of this are:
- a garden hose sitting in a rain barrel, or a kiddie pool.
- a bidet that is filled to above the faucet
- a bathtub that is filled to above the faucet
- a dish pit hose resting in a full sink
- This can cause contamination if there is backflow of the non-potable water into the potable water system (negative pressure)
- this is why there are backflow prevention devices such as check valves, and air gaps
What is a trap (plumbing), and what does it do?
A u-shaped pipe located in the drains of sinks, toilets, and other fixtures that holds a small amount of water, which prevents gases from flowing back out of drains.
These traps require the use of vents (pipes going outside, often to roof) to prevent siphoning of the water in the trap, as pressure builds up when other drains are used.
What are the recommended chemistry parameters for commercial pools and spas?
Explain the rationale for each chemical parameter
-FAC: 0.5-10 ppm (pools) 5-10 ppm (spas) 1-10 ppm (when CYA used)
Br: 2-4 ppm (pools) 5ppm-10 ppm (spas) 3-10ppm (wave pools)
This signifies the amount of disinfectant that can interact with organic material, and provide disinfection. if this level is too low, the disinfectant can’t do it’s job, too high, and the chemical itself becomes a health hazard.
-pH: 7.2-7.8
Chlorine is more effective in acidic environments (low pH), but that would cause corrosion. pH that is too high can cause scale, and cloudy water, and it can inhibit chlorines effectiveness
-ORP: 600-900 mV
indicates the potential of disinfectant to do work (oxidation/reduction reactions) basically a measure that is not fooled by factors like pH and TDS
- Total Alkalinity: 80ppm-120 ppm
- indicates the ability of the pool water to withstand swings in pH
-Cyanuric acid: <60 mg/L
stabilizes chlorine in outdoor pools, because the sun rapidly breaks it down. CYA should not be used indoors (sometimes people use pucks made for outdoor pools that contain CYA without knowing it)
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What is the significance of total chlorine (TC) in pool water
Total chlorine = FAC + combined chlorine
combined chlorine is chlorine that is bound to organic material
the only way to get rid of it is by draining, and adding fresh water to dilute.
combined chlorine, aka chloramines cause the stanky “chlorine” smell, and also cause eye irritation
What does it mean when a sample comes back as “overgrown”?
It means that there is so much bacteria on the plate that they can not be counted.
NDOGN (No Data: Overgrown with non-target) means that there are other bacteria make it impossible to tell total coliform or e. coli counts, so the source water could be unsafe
NDOGT (No Data: Overgrown with target)
too many e. coli or coliform to count: water source is definitely unsafe
What actions do you take if the owner of a private water system says that their water sample contained bacteria?
- determine if the well serves the public, or a private residence
- determine what the exact results are, how many coliform, and how many e. Coli?
- If a private residence, results should not exceed 5 total coliform, and 0 e. Coli
- if a SDWS, there should be 0 total coliform, and 0 e. Coli
-ask about how the sample was handled: how long did it spend at room temperature?
(it should be refrigerated, and delivered to lab within one day of sampling- not doing this can cause bacterial growth to amplify)
-determine where the water is drawn from (dug/drilled well? Surface water?)
- how is the water treated?
- history of adverse results?
- if a SDWS, how many people does the system service?
- notify all users of water system to use an alternate source, or boil water for one minute (post signage at all sources)
- re-test the water (might have been error in sampling, or some other fluke that caused the result)
- get documentation in writing from the operator detailing their plan of action
- BWA can be rescinded after 2 samples come back without adverse results (minimum 24 hours apart)
What is Turnover rate?
The rate at which the volume of water is filtered, disinfected & returned to the pool each day.
Class A = 4x/day
Class B = 3x/day
Six requirements for Chlorine Gas in a pool:
1) Automatic shut-off valve
2) Fixed (chained) / anchored
3) On weight scale
4) Trained operator
5) Wrench needs to be on valve for fast response to shut off
6) Respirators located outside where PPE is stored (must be full-faced mask with air supply)
Procedure for fecal/vomit incident in a spa
1) close spa. Turn off hydro jet pump, filter & heater.
2) Remove fecal matter with a scooping device. Dispose of fecal matter in toilet. Clean and disinfect device.
3) Drain the whirlpool
4) Use rubber gloves & face mask when working around the tank& mechanical equipment. Ensure pool is well-ventilated
5) Scrub & clean with detergent all accessible surfaces in contact with contaminated water. Rinse detergent.
6) Fill spa with uncontaminated water & shock chlorinate
7) Turn system back on
8) Disinfect deck area with 100 ppm Cl or 200ppm QUAT
9)Backwash filter and drain spa to waste
10) Refill spa, turn on recirculation equipment, balance water
Reasons for spa closure
- lack of water clarity
- fouling - faecal, vomit or chemical - filtration or circulation system inoperative or malfunctioning
- no free available sanitizer
- outlet covers not secured properly
- failure of operator to demonstrate the suction vacuum relief system (SVRS) test competently or, the test itself fails
- emergency telephone missing or not working
- emergency stop button inoperable/malfunctioning
- audible and visual signal inoperable/malfunctioning
- ground fault circuit interrupter missing or malfunctioning
- spa temperature greater than 40ºC (104ºF)
- spa water heater not equipped with an operational tamper-proof upper limit cut-off switch
- a swimming pool that has been closed and access to the spa is in the same room
What is the most common cause of splash pad associated outbreaks
Cryptosporidiosis
Components of a SDWS directive
(1) Risk Assessment Process
(2) Treatment Equipment
(3) Sampling and Testing
(4) Operational Checks
(5) Posting of Warning Signage
(6) Records
(7) Operator Training
What questions should you ask a homeowner in response to well water results that indicate E. coli?
- What type of well is it?
- What is the condition of the well?
- Where is the well located?
- Are there potential sources of contamination nearby (e.g., septic system, surface water, farm, etc.)? Do you live down hill, has there been rain recently?
- Are there any issues with the septic system?
- What is the sampling history of the well?
- Has there been any recent maintenance or repairs associated with the well?
