Wastewater Operator Certification Study Guide – Grade 2
| Actual Exam Questions & 100% Correct Answers |
Latest Update 2026 | Certification Exam Prep
1. In a scenario where a wastewater treatment facility is experiencing high levels
of acidity, what immediate action should be taken to protect the biological
treatment process?
Increase the temperature of the treatment process.
Reduce the flow rate of wastewater entering the facility.
Add more organic matter to the treatment tanks.
Adjust the pH levels to neutralize the acidity.
2. What is the typical percentage range for the removal of settleable solids in a
primary clarifier?
50% to 70%
10% to 30%
30% to 50%
70% to 90%
3. Why is it important to maintain a minimum depth in a waste pond?
The depth is irrelevant to treatment effectiveness.
A deeper pond allows for more evaporation.
Maintaining a minimum depth in a waste pond helps to ensure
proper treatment and prevents the accumulation of harmful
substances.
Shallower ponds are easier to maintain.
,4. Secondary clarifiers are usually located after:
an anaerobic digester
primary clarifier
a biological process
5. When coagulant is used, primary clarifiers remove of the total
suspended solids.
60% to 90%
25% to 40%
50% to 60%
50% to 75%
6. What is the typical distance range between manholes in wastewater
treatment facilities?
300 to 400 feet
100 to 200 feet
500 to 600 feet
700 to 800 feet
7. What does MLVSS stand for in wastewater treatment?
Maximum Liquid Volume Suspended Solids
Minimum Liquid Volatile Solids
Mixed Liquid Viscous Solids
Mixed Liquor Volatile Suspended Solids
,8. What type of ponds are used after a trickling filter, activated sludge, or RBC
plant?
Anaerobic pond
Polishing pond
Facultative pond
Aeration Pond
9. What is the primary purpose of ballast blocks in anaerobic digesters?
They increase the temperature of the digester.
They enhance the digestion process.
They filter out solids from the wastewater.
They provide stability to the digester.
10. What time of day is typically associated with the lowest pH levels in a waste
pond?
Early morning
Late afternoon
Evening
Midday
11. Which substances are known to be corrosive and can disrupt biological
treatment processes in wastewater?
acids and alkalies
organic toxicants
cyanide
, heavy metals
12. If a primary clarifier is operating at 40% removal efficiency for settleable
solids, what impact might this have on the secondary treatment process?
It may lead to increased solids loading and reduced efficiency in
the secondary treatment process.
It will improve the efficiency of the secondary treatment process.
It will have no impact on the secondary treatment process.
It will decrease the need for sludge handling.
13. Why is measuring BOD important in wastewater treatment?
Measuring BOD is important because it assesses the clarity of the
water.
Measuring BOD is important because it shows the temperature of the
water.
Measuring BOD is important because it determines the pH level of
the water.
Measuring BOD is important because it indicates the amount of
organic matter in the water, which affects the treatment process.
14. Regarding waste pond lab sampling, which parameter is sampled at the
influent of the pond?
DO
pH
BOD
15. In a wastewater treatment facility, if the levels of suspended solids and BOD
are found to be increasing, what action should the operators take to address
| Actual Exam Questions & 100% Correct Answers |
Latest Update 2026 | Certification Exam Prep
1. In a scenario where a wastewater treatment facility is experiencing high levels
of acidity, what immediate action should be taken to protect the biological
treatment process?
Increase the temperature of the treatment process.
Reduce the flow rate of wastewater entering the facility.
Add more organic matter to the treatment tanks.
Adjust the pH levels to neutralize the acidity.
2. What is the typical percentage range for the removal of settleable solids in a
primary clarifier?
50% to 70%
10% to 30%
30% to 50%
70% to 90%
3. Why is it important to maintain a minimum depth in a waste pond?
The depth is irrelevant to treatment effectiveness.
A deeper pond allows for more evaporation.
Maintaining a minimum depth in a waste pond helps to ensure
proper treatment and prevents the accumulation of harmful
substances.
Shallower ponds are easier to maintain.
,4. Secondary clarifiers are usually located after:
an anaerobic digester
primary clarifier
a biological process
5. When coagulant is used, primary clarifiers remove of the total
suspended solids.
60% to 90%
25% to 40%
50% to 60%
50% to 75%
6. What is the typical distance range between manholes in wastewater
treatment facilities?
300 to 400 feet
100 to 200 feet
500 to 600 feet
700 to 800 feet
7. What does MLVSS stand for in wastewater treatment?
Maximum Liquid Volume Suspended Solids
Minimum Liquid Volatile Solids
Mixed Liquid Viscous Solids
Mixed Liquor Volatile Suspended Solids
,8. What type of ponds are used after a trickling filter, activated sludge, or RBC
plant?
Anaerobic pond
Polishing pond
Facultative pond
Aeration Pond
9. What is the primary purpose of ballast blocks in anaerobic digesters?
They increase the temperature of the digester.
They enhance the digestion process.
They filter out solids from the wastewater.
They provide stability to the digester.
10. What time of day is typically associated with the lowest pH levels in a waste
pond?
Early morning
Late afternoon
Evening
Midday
11. Which substances are known to be corrosive and can disrupt biological
treatment processes in wastewater?
acids and alkalies
organic toxicants
cyanide
, heavy metals
12. If a primary clarifier is operating at 40% removal efficiency for settleable
solids, what impact might this have on the secondary treatment process?
It may lead to increased solids loading and reduced efficiency in
the secondary treatment process.
It will improve the efficiency of the secondary treatment process.
It will have no impact on the secondary treatment process.
It will decrease the need for sludge handling.
13. Why is measuring BOD important in wastewater treatment?
Measuring BOD is important because it assesses the clarity of the
water.
Measuring BOD is important because it shows the temperature of the
water.
Measuring BOD is important because it determines the pH level of
the water.
Measuring BOD is important because it indicates the amount of
organic matter in the water, which affects the treatment process.
14. Regarding waste pond lab sampling, which parameter is sampled at the
influent of the pond?
DO
pH
BOD
15. In a wastewater treatment facility, if the levels of suspended solids and BOD
are found to be increasing, what action should the operators take to address
