WATER OPERATOR CLASS 3
QUESTIONS AND ANSWERS 2026
- 2027
What is the most common taste in odor treatment currently in use -
ANSWERS-Chemical oxidation
When using potassium permanganate to oxidize objectionable odors,
why is it important to ensure that all the potassium permanganate is
oxidized before filtration? - ANSWERS-It will pass through the filters
into the distribution system
What can an operator do when a potassium permanganate overdose
occurs - ANSWERS-Apply powdered activated carbon
Which bluish unstable chemical generated by passing oxygen through
electricity is used as an oxidizer and water treatment? - ANSWERS-
Ozone
What device is used to mix Ozone with water - ANSWERS-Contactor
Excluding chemical oxidation, what is another common form of taste
and odor control on the United States? - ANSWERS-Powdered
activated carbon
,Prolonged detection of odors by humans is difficult due to what
condition - ANSWERS-Olfactory fatigue
Which disinfectant is produced by the reaction of sodium chloride and
chlorine - ANSWERS-Chlorine dioxide
One of the two primary considerations when using granular activated
carbon to control taste and odors is when to regenerate the carbon
what is the other? - ANSWERS-Empty bed contact time
Which law prohibits the discharge of process waste from water
treatment plants? - ANSWERS-Public law PL 92-500
What major factors determine the amount of sludge volume produced
at a water treatment facility - ANSWERS-Suspended matter and
coagulant
How often should sedimentation tanks be cleaned and inspected? -
ANSWERS-Minimum of twice a year
Where are processed wastes from lime soda ash softening plants
usually stored - ANSWERS-Lagoons
There are three main processes used to reduce the volume of sludge
that must be disposed of. Thickening and conditioning or two what is
the third? - ANSWERS-Dewatering
,Why is discharging lime soda ash sludge to sanitary sewers not a
widely used disposal method - ANSWERS-Sewers can become
plugged
Solar lagoons are small volume storage ponds that hold sludge until it
is dried and can be removed. How many solar lagoons should a water
plant have on site - ANSWERS-Three
What structure is typically included at the intake of a reservoir is a
pre-treatment step - ANSWERS-Bar screen
When using a sludge drying bed when is the correct time to remove
the sludge? - ANSWERS-When 1 foot has dried and cracked
What type of dewatering equipment is best suited for hard to dewater
alum sludge - ANSWERS-Filter presses
Why must Alum sludge not be applied to agricultural land like lime
sludge - ANSWERS-Alum sludge hardens the soil
What is the term used to describe the drop in the level of water in a
well when water is being pumped? - ANSWERS-Drawdown
What is the term used when a portion of a stream or river is used as a
water supply - ANSWERS-Diversion
, What may be the cause of flock break up after the flocculation
process? - ANSWERS-Mixing speed is too high
Which listed substance is a weighting agent used in water treatment -
ANSWERS-Bentonite
What is the term used to describe the rate of water flow through a
membrane treatment process? - ANSWERS-Flux
What is the term used to describe water produced from a reverse
osmosis treatment unit - ANSWERS-Permeate
Why is acid commonly added to the feed water of a cellulose acetate
membrane treatment unit? - ANSWERS-To reduce hydrolysis
What compound is used to regenerate an ion exchange softener? -
ANSWERS-Sodium chloride
What is the term used to express when calcium and magnesium
contained in an ion exchange unit or exchange for feed Water that has
a high sodium content - ANSWERS-Hardness leakage
What effect will algae in a reservoir have on dissolved oxygen? -
ANSWERS-Increase DO during the day and lower DO during the
night
QUESTIONS AND ANSWERS 2026
- 2027
What is the most common taste in odor treatment currently in use -
ANSWERS-Chemical oxidation
When using potassium permanganate to oxidize objectionable odors,
why is it important to ensure that all the potassium permanganate is
oxidized before filtration? - ANSWERS-It will pass through the filters
into the distribution system
What can an operator do when a potassium permanganate overdose
occurs - ANSWERS-Apply powdered activated carbon
Which bluish unstable chemical generated by passing oxygen through
electricity is used as an oxidizer and water treatment? - ANSWERS-
Ozone
What device is used to mix Ozone with water - ANSWERS-Contactor
Excluding chemical oxidation, what is another common form of taste
and odor control on the United States? - ANSWERS-Powdered
activated carbon
,Prolonged detection of odors by humans is difficult due to what
condition - ANSWERS-Olfactory fatigue
Which disinfectant is produced by the reaction of sodium chloride and
chlorine - ANSWERS-Chlorine dioxide
One of the two primary considerations when using granular activated
carbon to control taste and odors is when to regenerate the carbon
what is the other? - ANSWERS-Empty bed contact time
Which law prohibits the discharge of process waste from water
treatment plants? - ANSWERS-Public law PL 92-500
What major factors determine the amount of sludge volume produced
at a water treatment facility - ANSWERS-Suspended matter and
coagulant
How often should sedimentation tanks be cleaned and inspected? -
ANSWERS-Minimum of twice a year
Where are processed wastes from lime soda ash softening plants
usually stored - ANSWERS-Lagoons
There are three main processes used to reduce the volume of sludge
that must be disposed of. Thickening and conditioning or two what is
the third? - ANSWERS-Dewatering
,Why is discharging lime soda ash sludge to sanitary sewers not a
widely used disposal method - ANSWERS-Sewers can become
plugged
Solar lagoons are small volume storage ponds that hold sludge until it
is dried and can be removed. How many solar lagoons should a water
plant have on site - ANSWERS-Three
What structure is typically included at the intake of a reservoir is a
pre-treatment step - ANSWERS-Bar screen
When using a sludge drying bed when is the correct time to remove
the sludge? - ANSWERS-When 1 foot has dried and cracked
What type of dewatering equipment is best suited for hard to dewater
alum sludge - ANSWERS-Filter presses
Why must Alum sludge not be applied to agricultural land like lime
sludge - ANSWERS-Alum sludge hardens the soil
What is the term used to describe the drop in the level of water in a
well when water is being pumped? - ANSWERS-Drawdown
What is the term used when a portion of a stream or river is used as a
water supply - ANSWERS-Diversion
, What may be the cause of flock break up after the flocculation
process? - ANSWERS-Mixing speed is too high
Which listed substance is a weighting agent used in water treatment -
ANSWERS-Bentonite
What is the term used to describe the rate of water flow through a
membrane treatment process? - ANSWERS-Flux
What is the term used to describe water produced from a reverse
osmosis treatment unit - ANSWERS-Permeate
Why is acid commonly added to the feed water of a cellulose acetate
membrane treatment unit? - ANSWERS-To reduce hydrolysis
What compound is used to regenerate an ion exchange softener? -
ANSWERS-Sodium chloride
What is the term used to express when calcium and magnesium
contained in an ion exchange unit or exchange for feed Water that has
a high sodium content - ANSWERS-Hardness leakage
What effect will algae in a reservoir have on dissolved oxygen? -
ANSWERS-Increase DO during the day and lower DO during the
night
