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VIRGINIA WASTEWATER WORKS OPERATOR CLASS 3
EXAM NEWEST 2026 ACTUAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED ANSWERS)
ALL ANSWERED {100 Q & A} ALREADY GRADED A+ |
BRAND NEW! | 100% GUARANTEED PASS
1. Which of the following is an advantage of sequencing
batch reactors (SBRs)?
A. Continuous flow only
B. Flexibility in process control and combined treatment in one
tank
C. Only suitable for large plants
D. Requires no aeration
Rationale: SBRs operate in timed cycles, allowing biological
treatment, settling, and decanting in one tank.
2. What is the main purpose of secondary treatment?
A. Remove large debris
B. Remove most organics via biological processes
C. Disinfect wastewater
D. Thicken sludge
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Answer: B
Rationale: Secondary treatment biologically reduces organic
content.
3. Which safety device detects low oxygen in confined spaces?
A. Sludge judge
B. Oxygen meter
C. Flow meter
D. Barometer
Answer: B
Rationale: Oxygen meters ensure safe atmospheric conditions.
4. What process occurs when bacteria convert nitrate to nitrogen
gas?
A. Coagulation
B. Denitrification
C. Aeration
D. Sedimentation
Answer: B
Rationale: Denitrification reduces nitrate under anoxic conditions.
5. What is the primary function of a digester mixing system?
A. Reduce odor
B. Maintain uniform temperature and solids distribution
C. Increase flow rate
D. Remove grit
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Answer: B
Rationale: Proper mixing stabilizes digestion and prevents
stratification.
6. Which factor most influences settling in a clarifier?
A. Alkalinity
B. Temperature
C. Sludge blanket depth
D. Chlorine dose
Answer: C
Rationale: Excessive blankets impair separation and cause
carryover.
7. What is a common cause of foaming in activated sludge?
A. High alkalinity
B. Nocardia filaments
C. High chlorine
D. Low temperature
Answer: B
Rationale: Nocardia species produce stable foam.
8. What is the typical efficiency of secondary BOD removal?
A. 10–20%
B. 25–40%
C. 50–60%
D. 85–95%
Answer: D
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Rationale: Properly operated secondary systems remove most
biodegradable organics.
9. The term RAS refers to:
A. Return activated sludge
B. Reduced aeration system
C. Recycled alkaline solution
D. Raw aerated solids
Answer: A
Rationale: RAS recycles settled microbes to sustain treatment.
10. What does TSS measure?
A. Volatile gases
B. Suspended solid particles
C. Dissolved metals
D. Biological oxygen use
Answer: B
Rationale: TSS quantifies solids retained on a filter.
11. Which factor increases oxygen demand in aeration tanks?
A. Low temperature
B. High organic loading
C. Low MLSS
D. High pH
VIRGINIA WASTEWATER WORKS OPERATOR CLASS 3
EXAM NEWEST 2026 ACTUAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED ANSWERS)
ALL ANSWERED {100 Q & A} ALREADY GRADED A+ |
BRAND NEW! | 100% GUARANTEED PASS
1. Which of the following is an advantage of sequencing
batch reactors (SBRs)?
A. Continuous flow only
B. Flexibility in process control and combined treatment in one
tank
C. Only suitable for large plants
D. Requires no aeration
Rationale: SBRs operate in timed cycles, allowing biological
treatment, settling, and decanting in one tank.
2. What is the main purpose of secondary treatment?
A. Remove large debris
B. Remove most organics via biological processes
C. Disinfect wastewater
D. Thicken sludge
,Page 2 of 46
Answer: B
Rationale: Secondary treatment biologically reduces organic
content.
3. Which safety device detects low oxygen in confined spaces?
A. Sludge judge
B. Oxygen meter
C. Flow meter
D. Barometer
Answer: B
Rationale: Oxygen meters ensure safe atmospheric conditions.
4. What process occurs when bacteria convert nitrate to nitrogen
gas?
A. Coagulation
B. Denitrification
C. Aeration
D. Sedimentation
Answer: B
Rationale: Denitrification reduces nitrate under anoxic conditions.
5. What is the primary function of a digester mixing system?
A. Reduce odor
B. Maintain uniform temperature and solids distribution
C. Increase flow rate
D. Remove grit
,Page 3 of 46
Answer: B
Rationale: Proper mixing stabilizes digestion and prevents
stratification.
6. Which factor most influences settling in a clarifier?
A. Alkalinity
B. Temperature
C. Sludge blanket depth
D. Chlorine dose
Answer: C
Rationale: Excessive blankets impair separation and cause
carryover.
7. What is a common cause of foaming in activated sludge?
A. High alkalinity
B. Nocardia filaments
C. High chlorine
D. Low temperature
Answer: B
Rationale: Nocardia species produce stable foam.
8. What is the typical efficiency of secondary BOD removal?
A. 10–20%
B. 25–40%
C. 50–60%
D. 85–95%
Answer: D
, Page 4 of 46
Rationale: Properly operated secondary systems remove most
biodegradable organics.
9. The term RAS refers to:
A. Return activated sludge
B. Reduced aeration system
C. Recycled alkaline solution
D. Raw aerated solids
Answer: A
Rationale: RAS recycles settled microbes to sustain treatment.
10. What does TSS measure?
A. Volatile gases
B. Suspended solid particles
C. Dissolved metals
D. Biological oxygen use
Answer: B
Rationale: TSS quantifies solids retained on a filter.
11. Which factor increases oxygen demand in aeration tanks?
A. Low temperature
B. High organic loading
C. Low MLSS
D. High pH
