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2024 CLASS A WATER OPERATOR EXAM WITH CORRECT ANSWERS
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2024 CLASS A WATER OPERATOR EXAM WITH CORRECT ANSWERS
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2024 CLASS A WATER OPERATOREXAM WITH CORRECT ANSWERS
What is the main cause of lead and copper contamination in drinking water?
- CORRECT-ANSWERSCorrosive water. Most problems are household
plumbing leaching copper and lead solder.
What is "Stable" Water - CORRECT-ANSWERSWater that is just saturated with
Calcium Carbonate (CaCO3) so that it will neither be corrosive or leave a
deposite of calcium carbonate "scaling".
Tuberculation - CORRECT-ANSWERSCaused by internal pipe corrosion and/or
a build-up of rust. Tuberculation cannot be detected
without an internal inspection. Build-ups in the valve may be an indication
that the same is happening within the pipes.
Such a build-up can significantly change the volume of water delivered by a
system.
Marble test (Calcium Carbonate Stability Test) - CORRECT-ANSWERSTest
used to measure the "Stability" of water. Determines the saturation level of
calcium carbonate (CaCO3)
Treatment for corrosive water - CORRECT-ANSWERSTreated with chemicals
so that the water is saturated or slightly supersaturated with Calcium
Carbonate (CaCO3).
For water with low hardness and low alkalinity:
Quicklime - Calcium Oxide (CaO)
"Slaked" Lime - Calcium Hydroxide (Ca(OH)2)
For water with high hardness and high alkalinity and when pH levels need to
rise:
Caustic Soda - Sodium Hydroxide (NaOH)
Soda Ash - Sodium Carbonate (Na2CO3)
Indexes used to determine chemical dosage to change pH and produce
calcium carbonate saturation - CORRECT-ANSWERSLangelier Index
Driving Force Index
Aggressive Index
, Most common complaint about water quality - CORRECT-ANSWERSTaste and
Odor along with "colored water"
Causes of Taste and Odor problems - CORRECT-ANSWERSMicro organisms
produce "metabolic by-products" and cellular material are released into
water when they die.
Low dissolved oxygen levels (caused by increased nutrient levels or
increased algae activity). Anaerobic micro capable of producing Hydrogen
Sulfide (H2S).
Man-made causes from poor municipal treatment, industrial wastewater, or
poor surface water.
Consumers plumbing system
Taste and Oder Treatments - CORRECT-ANSWERS"Degasification" to remove
dissolved gases from water
"Adsorption" by adding chemicals to the treatment process that attract odor
producing compounds
"Chemical oxidation" to destroy taste and odors instead of removing them.
Chrenothrix or Iron Bacteria - CORRECT-ANSWERSCaused by high
concentration of Iron and Manganese and form thick slimes on inter walls of
well casings and distribution lines (reddish brown or black in color depending
on whether iron or manganese is dominant)
Treatment of Iron and Manganese - CORRECT-ANSWERSif water contains no
more than 0.3 mg/L Manganese and 0.1 mg/L iron then "Polyphosphate" can
be used. It is a sequestering agent that keeps the iron and manganese from
precipitating for a few days.
Chlorine should be fed along with polyphosphate to eliminate chrenothrix or
iron bacteria. Chlorine should NEVER be fed ahead of polyphosphate because
it will cause the iron and manganese to precipitate.
Phosphate dosage max of 10 mg/L
Oxidation by Aeration is another treatment
Oxidation by chlorination
Oxidation with Pottasium Permanganate (KMnO4)
Water softening
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