WASTEWATER TREATMENT PLANT OPERATOR
CLASS C EXAMINATION 2026
Fundamentals of Wastewater Treatment, Process Control, Safety, and
Facility Operations Assessment
Examination Level: Entry-Level Operator Certification (Class C)
Wastewater Treatment Plant Operations and Environmental
Compliance
SPRING SEMESTER EXAM 2026
When Chlorine is combined with water what type of pipe should be used?
A. Ductile iron
B. Asbestos concrete
C. PVC
D. Carbon Steel
C. PVC
A good settling sludge would consist of what type of protozoa?
A. Rotifers and nematodes
B. Amoebas and Flagellates
1
Page
C. Stalked ciliates and mastagoria
, D. Free swimmers and stalk ciliates
D. Free swimmers and stalk ciliates
What is Phenolphylein used for in titration
A. Oxidizer
B. Indicator
C. Acid reducer to lower pH
D. Applicator
B. Indicator
Your plant has an influent of 220 BOD and 163 TSS, and an effluent of 10 BOD, and 6 TSS. What
is the BOD removal efficiency in your plant?
A. 92%
B. 94%
C. 95%
D. 96%
C. 95%
You suspect your anaerobic digester is going sour. What is the best way to verify its condition?
2
A. pH
Page
, B. Foam type
C. VA/ALK ratio
D. DO
C. VA/ALK ratio
Before operating any piece of equipment what should be done?
A. Lock out Tag out (remember, safety first!)
B. Read O & M manual
C. Read manufacturers manual
D. Notify supervisor
C. Read manufacturers manual
Detritus is noticed in your grit channel. What is the problem?
A. Velocity too fast with short D/T
B. Velocity too low with long D/T
C. Short circuiting
D. Density currents
B. Velocity too low with long D/T
What is considered normal operation of an aerobic digester?
3
Page
, A. Fill react
B. Skim off foam when needed
C. Settle and Decant as needed
D. Feed only during low flow or constant when the sun is out
C. Settle and Decant as needed
A plant with a flow of 1 MGD should be monitored
A. Continuously
B. Intermittently
C. Daily
D. Every four hours depending on surface load
A. Continuously
What do total solids consist of?
A. Dissolved and settleable
B. Floatable and settlable
C. Suspended and dissolved
D. Settlable and nonsettleable
C. Suspended and dissolved
4
Page
What would cause excessive wear on bearing?
CLASS C EXAMINATION 2026
Fundamentals of Wastewater Treatment, Process Control, Safety, and
Facility Operations Assessment
Examination Level: Entry-Level Operator Certification (Class C)
Wastewater Treatment Plant Operations and Environmental
Compliance
SPRING SEMESTER EXAM 2026
When Chlorine is combined with water what type of pipe should be used?
A. Ductile iron
B. Asbestos concrete
C. PVC
D. Carbon Steel
C. PVC
A good settling sludge would consist of what type of protozoa?
A. Rotifers and nematodes
B. Amoebas and Flagellates
1
Page
C. Stalked ciliates and mastagoria
, D. Free swimmers and stalk ciliates
D. Free swimmers and stalk ciliates
What is Phenolphylein used for in titration
A. Oxidizer
B. Indicator
C. Acid reducer to lower pH
D. Applicator
B. Indicator
Your plant has an influent of 220 BOD and 163 TSS, and an effluent of 10 BOD, and 6 TSS. What
is the BOD removal efficiency in your plant?
A. 92%
B. 94%
C. 95%
D. 96%
C. 95%
You suspect your anaerobic digester is going sour. What is the best way to verify its condition?
2
A. pH
Page
, B. Foam type
C. VA/ALK ratio
D. DO
C. VA/ALK ratio
Before operating any piece of equipment what should be done?
A. Lock out Tag out (remember, safety first!)
B. Read O & M manual
C. Read manufacturers manual
D. Notify supervisor
C. Read manufacturers manual
Detritus is noticed in your grit channel. What is the problem?
A. Velocity too fast with short D/T
B. Velocity too low with long D/T
C. Short circuiting
D. Density currents
B. Velocity too low with long D/T
What is considered normal operation of an aerobic digester?
3
Page
, A. Fill react
B. Skim off foam when needed
C. Settle and Decant as needed
D. Feed only during low flow or constant when the sun is out
C. Settle and Decant as needed
A plant with a flow of 1 MGD should be monitored
A. Continuously
B. Intermittently
C. Daily
D. Every four hours depending on surface load
A. Continuously
What do total solids consist of?
A. Dissolved and settleable
B. Floatable and settlable
C. Suspended and dissolved
D. Settlable and nonsettleable
C. Suspended and dissolved
4
Page
What would cause excessive wear on bearing?
