WASTEWATER OPERATOR CLASS C
COMPREHENSIVE EXAMINATION TEST 2026
QUESTIONS AND CORRECT ANSWERS
◉ The definition of an oxygen-deficient atmosphere is one that contains
less than, what percentage of oxygen? Answer: 19.5
◉ 1.) What is the function of a grit auger? Answer: To Separate Organic
from Inorganics
◉ 2.) Running a 30 min settling test is the best indication of what?
Answer: What is taking place in the Clarifier.
◉ 3.) How many inches do you pour a sludge drying bed? Answer: 8 to
12
◉ 4.) Why do you draw sludge into the drying bed at a slow rate?
Answer: To promote drying of the sludge.
◉ 5.) In the F/M ratio what does the food stand for? Answer: Organics
,◉ 6.) What can chlorine be used for in a trickiling filter? Answer:
Reduce Ponding
◉ 7.) One part of liquid chlorine equals how much of Gas? Answer: 450
◉ 8.) What is the purpose of a pretreatment program? Answer: To cut
cost and help with plant efficiency
◉ 9.) In a composite sample there was a Cl2 sample ran and there was
no residual present, what does that say about the sample? Answer:
Inaccurate, Cl2 test is within 15 min, not 24 hours later
◉ 10.) In order to be a good communicator, what else do you need to
be? Answer: Listener
◉ 11.) During Nitrification, which organisms use ______ for food?
Answer: Nitrates
◉ In an Activated Sludge Treatment Process what is the most
predominant organism? Answer: Ciliates and rotifers with few
flagellates.
, ◉ The Detention Time in a Contact Stabilization plant is _____ than
other extended aeration plants. Answer: Longer
◉ 14.) Other than disinfection chlorination can be used for what?
Answer: Odor Control, Foaming, Reduce Algae Growth
◉ 15.) A leaking chlorine cylinder will do what? Answer: Have a frosty
coated outside
◉ 16.) Who has the right to training and education? Answer: Everyone
◉ 17.) When connecting a potable water line to a wastewater pump for
cooling, what do you need to put in place? Answer: Check Valve
◉ What is the expected % of removal of the settable solids from a
primary clarifier? Answer: 90% to 99%)
◉ 19.) Manholes should be placed where? Answer: Every 500ft, change
in elevation, pipe size or all of the above
◉ 20.) A high SVI would represent what about your sludge? Answer:
Bulking sludge
COMPREHENSIVE EXAMINATION TEST 2026
QUESTIONS AND CORRECT ANSWERS
◉ The definition of an oxygen-deficient atmosphere is one that contains
less than, what percentage of oxygen? Answer: 19.5
◉ 1.) What is the function of a grit auger? Answer: To Separate Organic
from Inorganics
◉ 2.) Running a 30 min settling test is the best indication of what?
Answer: What is taking place in the Clarifier.
◉ 3.) How many inches do you pour a sludge drying bed? Answer: 8 to
12
◉ 4.) Why do you draw sludge into the drying bed at a slow rate?
Answer: To promote drying of the sludge.
◉ 5.) In the F/M ratio what does the food stand for? Answer: Organics
,◉ 6.) What can chlorine be used for in a trickiling filter? Answer:
Reduce Ponding
◉ 7.) One part of liquid chlorine equals how much of Gas? Answer: 450
◉ 8.) What is the purpose of a pretreatment program? Answer: To cut
cost and help with plant efficiency
◉ 9.) In a composite sample there was a Cl2 sample ran and there was
no residual present, what does that say about the sample? Answer:
Inaccurate, Cl2 test is within 15 min, not 24 hours later
◉ 10.) In order to be a good communicator, what else do you need to
be? Answer: Listener
◉ 11.) During Nitrification, which organisms use ______ for food?
Answer: Nitrates
◉ In an Activated Sludge Treatment Process what is the most
predominant organism? Answer: Ciliates and rotifers with few
flagellates.
, ◉ The Detention Time in a Contact Stabilization plant is _____ than
other extended aeration plants. Answer: Longer
◉ 14.) Other than disinfection chlorination can be used for what?
Answer: Odor Control, Foaming, Reduce Algae Growth
◉ 15.) A leaking chlorine cylinder will do what? Answer: Have a frosty
coated outside
◉ 16.) Who has the right to training and education? Answer: Everyone
◉ 17.) When connecting a potable water line to a wastewater pump for
cooling, what do you need to put in place? Answer: Check Valve
◉ What is the expected % of removal of the settable solids from a
primary clarifier? Answer: 90% to 99%)
◉ 19.) Manholes should be placed where? Answer: Every 500ft, change
in elevation, pipe size or all of the above
◉ 20.) A high SVI would represent what about your sludge? Answer:
Bulking sludge
