Page 1 of 93
WASTEWATER OPERATOR CLASS C EXAM AND PRACTICE
EXAM NEWEST 2025 TEST BANK| COMPLETE 400 REAL
EXAM QUESTIONS AND CORRECT VERIFIED ANSWERS/
GRADED A+| WASTEWATER OPERATOR CLASS C TEST PREP
2025 (MOST RECENT!!)
What would cause excessive wear on bearing?
A. Misalignment
B. Reduced Oil due to low viscosity
C. Blow seal
D. Over tubercation -Correct Answer - A. Misalignment
Amperometric titration is used to measure
A. Dissolved solids
B. Chlorine residual
C. Colloids
D. Emulsions -Correct Answer - B. Chlorine residual
What growth phase is an aerobic digester operated in.
A. Log
B. Lag
C. Endogenous respiration
D. Declining phase -Correct Answer - C. Endogenous respiration
pg. 1
,Page 2 of 93
If excessive pressure builds up in a chlorine tank due to excessive heat.
What will prevent explosions?
A. Valve seat adjustments
B. Heat reducing valve
C. Fusible plug
D. Check valve -Correct Answer - C. Fusible plug
You notice that your bearings are excessively hot on a pump, why?
A. Ambient temperature too high
B. Over lubrication
C. Oil seal blown
D. Discharge rate too low -Correct Answer - B. Over lubrication
Where can you gain access for collection system maintenance?
A. Lift station
B. Force main
C. Man hole
D. Gravity main -Correct Answer - C. Man hole
Low DO and nutrient deficiency will promote the growth of what?
A. Rotifers
B. Filamentous bacteria
pg. 2
,Page 3 of 93
C. Spirillium
D. Amoebas -Correct Answer - B. Filamentous bacteria
When charging a lead-acid type battery for a composite sampler, what
dangerous gas could be produced?
A. Hydrogen
B. Oxygen
C. Hydrogen sulfide
D. Cyanide -Correct Answer - A. Hydrogen
What is the best method in dealing with a chemical spill?
A. Contain and clean up
B. Saw dust and kitty litter
C. Foam congaing super trimethyl bromine
D. Flood with water -Correct Answer - A. Contain and clean up
There is septic wastewater entering your primary clarifier. What is the
problem?
A. Aerobic conditions in the collections system
B. Lift station pumps operating on short cycles
C. Anaerobic conditions in the collections systems
D. High flows due to a low MCRT -Correct Answer - C. Anaerobic
condition in the collections system
pg. 3
, Page 4 of 93
Which of the following substances is highly viscous and very slippery?
A. Calcium hypochlorite
B. Calcium oxide
C. Potassium permanganate
D. Polymer -Correct Answer - D. Polymer
If you pump green sludge to a drying bed what chemical should be
applied?
A. Polymer
B. Lime
C. Cl2
D. Alum -Correct Answer - B. Lime
Chlorine leaks can be detected by?
A. ISCBA
B. Ammonia solution with Q-Tip
C. Alcohol vapor
D. Spray with mist of water -Correct Answer - B. Ammonia solution
with Q-Tip
What takes place in the stabilization tank in a contact stabilization plant?
A. Adsorption
B. Clarification
pg. 4
WASTEWATER OPERATOR CLASS C EXAM AND PRACTICE
EXAM NEWEST 2025 TEST BANK| COMPLETE 400 REAL
EXAM QUESTIONS AND CORRECT VERIFIED ANSWERS/
GRADED A+| WASTEWATER OPERATOR CLASS C TEST PREP
2025 (MOST RECENT!!)
What would cause excessive wear on bearing?
A. Misalignment
B. Reduced Oil due to low viscosity
C. Blow seal
D. Over tubercation -Correct Answer - A. Misalignment
Amperometric titration is used to measure
A. Dissolved solids
B. Chlorine residual
C. Colloids
D. Emulsions -Correct Answer - B. Chlorine residual
What growth phase is an aerobic digester operated in.
A. Log
B. Lag
C. Endogenous respiration
D. Declining phase -Correct Answer - C. Endogenous respiration
pg. 1
,Page 2 of 93
If excessive pressure builds up in a chlorine tank due to excessive heat.
What will prevent explosions?
A. Valve seat adjustments
B. Heat reducing valve
C. Fusible plug
D. Check valve -Correct Answer - C. Fusible plug
You notice that your bearings are excessively hot on a pump, why?
A. Ambient temperature too high
B. Over lubrication
C. Oil seal blown
D. Discharge rate too low -Correct Answer - B. Over lubrication
Where can you gain access for collection system maintenance?
A. Lift station
B. Force main
C. Man hole
D. Gravity main -Correct Answer - C. Man hole
Low DO and nutrient deficiency will promote the growth of what?
A. Rotifers
B. Filamentous bacteria
pg. 2
,Page 3 of 93
C. Spirillium
D. Amoebas -Correct Answer - B. Filamentous bacteria
When charging a lead-acid type battery for a composite sampler, what
dangerous gas could be produced?
A. Hydrogen
B. Oxygen
C. Hydrogen sulfide
D. Cyanide -Correct Answer - A. Hydrogen
What is the best method in dealing with a chemical spill?
A. Contain and clean up
B. Saw dust and kitty litter
C. Foam congaing super trimethyl bromine
D. Flood with water -Correct Answer - A. Contain and clean up
There is septic wastewater entering your primary clarifier. What is the
problem?
A. Aerobic conditions in the collections system
B. Lift station pumps operating on short cycles
C. Anaerobic conditions in the collections systems
D. High flows due to a low MCRT -Correct Answer - C. Anaerobic
condition in the collections system
pg. 3
, Page 4 of 93
Which of the following substances is highly viscous and very slippery?
A. Calcium hypochlorite
B. Calcium oxide
C. Potassium permanganate
D. Polymer -Correct Answer - D. Polymer
If you pump green sludge to a drying bed what chemical should be
applied?
A. Polymer
B. Lime
C. Cl2
D. Alum -Correct Answer - B. Lime
Chlorine leaks can be detected by?
A. ISCBA
B. Ammonia solution with Q-Tip
C. Alcohol vapor
D. Spray with mist of water -Correct Answer - B. Ammonia solution
with Q-Tip
What takes place in the stabilization tank in a contact stabilization plant?
A. Adsorption
B. Clarification
pg. 4
