Water Treatment Operator Level 1
Sample Questions (Water Operator
Certification Study Guide) Questions
and Answers 100% Pass
What are the two important factors impacting the effectiveness of chlorination? -
ANSWER-Concentration of chlorine and contact time
The treatment process that controls corrosion or scaling is known as what? -
ANSWER-Stabilization
Permanganate reactions are highly dependent on what factor? - ANSWER-pH
It is hardest to kill the organism that causes what illness? - ANSWER-
Cryptosporidiosis
Disinfection of water wells with free chlorine requires exposure for how long and
at what concentration? - ANSWER-12 to 24 hours; 50mg/L
Flocculation basins are usually designed to provide for detention times of how
long? - ANSWER-15 to 45 minutes
Alum works best in a pH range of what? - ANSWER-5.8 to 7.5
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, What has little effect on colloidal particles because of their small size? - ANSWER-
Gravity
What natural electrical force keeps colloidal particles apart in water treatment? -
ANSWER-Zeta potential
What does the zeta potential measure? - ANSWER-The number of excess
electrons found on the surface of all particulate matter
What device collects the settled water as it leaves the sedimentation basin? -
ANSWER-The effluent launder
In solid-contact basins with fairly constant water quality parameters, how often
should the solids concentration be determined? - ANSWER-At least twice per day
What is the definition of decant? - ANSWER-To draw off the liquid from a vessel
of any size without stirring up bottom sedimentation
How often should sedimentation basins with mechanical sludge removal
equipment be drained and inspected? - ANSWER-Once a year
What is the most important reason to reduce turbidity? - ANSWER-To remove
pathogens
What is the filtration flow rate through a manganese greensand pressure filter at 10
degrees C? - ANSWER-2 to 3 gpm/sq ft
©️COPYRIGHT 2025, ALL RIGHTS RESERVED. 2
Sample Questions (Water Operator
Certification Study Guide) Questions
and Answers 100% Pass
What are the two important factors impacting the effectiveness of chlorination? -
ANSWER-Concentration of chlorine and contact time
The treatment process that controls corrosion or scaling is known as what? -
ANSWER-Stabilization
Permanganate reactions are highly dependent on what factor? - ANSWER-pH
It is hardest to kill the organism that causes what illness? - ANSWER-
Cryptosporidiosis
Disinfection of water wells with free chlorine requires exposure for how long and
at what concentration? - ANSWER-12 to 24 hours; 50mg/L
Flocculation basins are usually designed to provide for detention times of how
long? - ANSWER-15 to 45 minutes
Alum works best in a pH range of what? - ANSWER-5.8 to 7.5
©️COPYRIGHT 2025, ALL RIGHTS RESERVED. 1
, What has little effect on colloidal particles because of their small size? - ANSWER-
Gravity
What natural electrical force keeps colloidal particles apart in water treatment? -
ANSWER-Zeta potential
What does the zeta potential measure? - ANSWER-The number of excess
electrons found on the surface of all particulate matter
What device collects the settled water as it leaves the sedimentation basin? -
ANSWER-The effluent launder
In solid-contact basins with fairly constant water quality parameters, how often
should the solids concentration be determined? - ANSWER-At least twice per day
What is the definition of decant? - ANSWER-To draw off the liquid from a vessel
of any size without stirring up bottom sedimentation
How often should sedimentation basins with mechanical sludge removal
equipment be drained and inspected? - ANSWER-Once a year
What is the most important reason to reduce turbidity? - ANSWER-To remove
pathogens
What is the filtration flow rate through a manganese greensand pressure filter at 10
degrees C? - ANSWER-2 to 3 gpm/sq ft
©️COPYRIGHT 2025, ALL RIGHTS RESERVED. 2
