Minnesota Water Treatment Operator
Level Ii Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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1. What is the primary purpose of coagulation in water treatment?
A. To disinfect water
B. To remove dissolved salts
C. To destabilize particles for removal
D. To increase water hardness
Answer: C
Coagulation neutralizes the charges of suspended particles, allowing
them to clump together for easier removal in later treatment stages.
2. Which chemical is most commonly used as a coagulant?
A. Chlorine
B. Alum
C. Fluoride
, D. Lime
Answer: B
Alum (aluminum sulfate) is widely used to destabilize suspended
particles in water treatment.
3. What process follows coagulation in conventional water treatment?
A. Filtration
B. Sedimentation
C. Disinfection
D. Aeration
Answer: B
Sedimentation allows floc particles formed during coagulation to
settle out by gravity.
4. What is the main purpose of filtration?
A. Remove large debris only
B. Remove suspended particles and microbes
C. Add disinfectant
D. Adjust pH
Answer: B
Filtration removes fine suspended particles and some
microorganisms from water.
5. Which disinfectant is most commonly used in water treatment plants?
A. Ozone
, B. Chlorine
C. Hydrogen peroxide
D. UV light
Answer: B
Chlorine is widely used due to its effectiveness and residual
disinfecting capability.
6. What does turbidity measure?
A. Water hardness
B. Water temperature
C. Cloudiness caused by particles
D. pH level
Answer: C
Turbidity indicates the cloudiness of water due to suspended
particles.
7. The ideal pH range for drinking water is:
A. 1–3
B. 4–5
C. 6.5–8.5
D. 9–11
Answer: C
Drinking water is generally safe and stable between pH 6.5 and 8.5.
, 8. What is floc?
A. Dissolved salt
B. Clumped particles formed during coagulation
C. Chlorine compound
D. Filter media
Answer: B
Floc refers to the aggregated particles formed after coagulation.
9. Which process removes hardness from water?
A. Sedimentation
B. Softening
C. Chlorination
D. Screening
Answer: B
Water softening removes calcium and magnesium ions that cause
hardness.
10. What is the purpose of aeration?
A. Add chlorine
B. Remove gases and oxidize iron
C. Remove solids
D. Increase hardness
Answer: B
Level Ii Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of coagulation in water treatment?
A. To disinfect water
B. To remove dissolved salts
C. To destabilize particles for removal
D. To increase water hardness
Answer: C
Coagulation neutralizes the charges of suspended particles, allowing
them to clump together for easier removal in later treatment stages.
2. Which chemical is most commonly used as a coagulant?
A. Chlorine
B. Alum
C. Fluoride
, D. Lime
Answer: B
Alum (aluminum sulfate) is widely used to destabilize suspended
particles in water treatment.
3. What process follows coagulation in conventional water treatment?
A. Filtration
B. Sedimentation
C. Disinfection
D. Aeration
Answer: B
Sedimentation allows floc particles formed during coagulation to
settle out by gravity.
4. What is the main purpose of filtration?
A. Remove large debris only
B. Remove suspended particles and microbes
C. Add disinfectant
D. Adjust pH
Answer: B
Filtration removes fine suspended particles and some
microorganisms from water.
5. Which disinfectant is most commonly used in water treatment plants?
A. Ozone
, B. Chlorine
C. Hydrogen peroxide
D. UV light
Answer: B
Chlorine is widely used due to its effectiveness and residual
disinfecting capability.
6. What does turbidity measure?
A. Water hardness
B. Water temperature
C. Cloudiness caused by particles
D. pH level
Answer: C
Turbidity indicates the cloudiness of water due to suspended
particles.
7. The ideal pH range for drinking water is:
A. 1–3
B. 4–5
C. 6.5–8.5
D. 9–11
Answer: C
Drinking water is generally safe and stable between pH 6.5 and 8.5.
, 8. What is floc?
A. Dissolved salt
B. Clumped particles formed during coagulation
C. Chlorine compound
D. Filter media
Answer: B
Floc refers to the aggregated particles formed after coagulation.
9. Which process removes hardness from water?
A. Sedimentation
B. Softening
C. Chlorination
D. Screening
Answer: B
Water softening removes calcium and magnesium ions that cause
hardness.
10. What is the purpose of aeration?
A. Add chlorine
B. Remove gases and oxidize iron
C. Remove solids
D. Increase hardness
Answer: B
