1|Page
Illinois Wastewater Operator Class 1 Exam Actual
Verified Exam Questions with Correct Answers and
explanations LATEST THIS YEAR -just
released.pdf||Newest Exam!!!
What are the different temperatures in which "Mesophilic"
& "Thermophilic" bacteria thrive in? - Answer-- Mesophilic
bacteria grow best at moderate temperatures [ 68°F
(20°C) - 113°F (45°C) ].
( Most human pathogens and the organisms in the human
microbiome are mesophilic.)
- Thermophilic bacteria grow best at higher temperatures [
140°F (60°C) and 176°F (80°C)].
(Thermophiles can be found in hot springs, deep sea
hydrothermal vents, and decaying plant matter.)
What are some parts of a Chlorinator and their purpose? -
Answer-- Rotameter
( Measures & controls the flow rate of the chemical feed )
- Saturator
( Maintains a set concentration of chemical being applied )
,2|Page
- Evaporator
( Converts liquid Chlorine to a gas )
- Gas Injector
( Applies the gas Chlorine to the water flow )
Where does sludge from a Primary Clarifier typically get
sent to in a Wastewater Treatment Plant? - Answer-An
Aerobic or Anaerobic Digestor
Will Amperage Draw go up or go down when a coupling is
starting to fail? - Answer-Amperage Draw will go down
What is the term used to describe the activated sludge
mixture in an Aeration Tank? - Answer-Mixed Liquor
What is the maximum thickness of sludge layer that
should be put on a "Drying Bed" at one time? - Answer-12
Inches Thick
,3|Page
What are 5 names of the different size pipes in a collection
system?
( Smallest to Largest ) - Answer-- Lateral ( Smallest )
- Branch
- Main
- Trunk
- Interceptor ( Largest )
What pipe layout is used in a collection system that needs
to go under a body of water; such as a river? - Answer-
"Inverted Siphon"
Pipes go underneath the body of water connecting
manholes on each side.
, 4|Page
Most important part is that the manhole on the receiving
side must be at a lower elevation than the sending side.
What is the desired velocity in a collection system & what
is the nickname used to describe the speed? - Answer-
Velocity = 2 Feet per Second ( F.P.S. )
Nickname = "Scouring Speed"
What are the 2 main types of electrical phases? - Answer-
Single-Phase ( 2 Wires )
Three-Phase ( 3 or 4 Wires )
What are 3 common chemicals that can be used to correct
an anaerobic digester upset by raising the pH? - Answer--
Calcium Hydroxide ( Quicklime )
- Sodium Bicarbonate
- Sodium Hydroxide
Illinois Wastewater Operator Class 1 Exam Actual
Verified Exam Questions with Correct Answers and
explanations LATEST THIS YEAR -just
released.pdf||Newest Exam!!!
What are the different temperatures in which "Mesophilic"
& "Thermophilic" bacteria thrive in? - Answer-- Mesophilic
bacteria grow best at moderate temperatures [ 68°F
(20°C) - 113°F (45°C) ].
( Most human pathogens and the organisms in the human
microbiome are mesophilic.)
- Thermophilic bacteria grow best at higher temperatures [
140°F (60°C) and 176°F (80°C)].
(Thermophiles can be found in hot springs, deep sea
hydrothermal vents, and decaying plant matter.)
What are some parts of a Chlorinator and their purpose? -
Answer-- Rotameter
( Measures & controls the flow rate of the chemical feed )
- Saturator
( Maintains a set concentration of chemical being applied )
,2|Page
- Evaporator
( Converts liquid Chlorine to a gas )
- Gas Injector
( Applies the gas Chlorine to the water flow )
Where does sludge from a Primary Clarifier typically get
sent to in a Wastewater Treatment Plant? - Answer-An
Aerobic or Anaerobic Digestor
Will Amperage Draw go up or go down when a coupling is
starting to fail? - Answer-Amperage Draw will go down
What is the term used to describe the activated sludge
mixture in an Aeration Tank? - Answer-Mixed Liquor
What is the maximum thickness of sludge layer that
should be put on a "Drying Bed" at one time? - Answer-12
Inches Thick
,3|Page
What are 5 names of the different size pipes in a collection
system?
( Smallest to Largest ) - Answer-- Lateral ( Smallest )
- Branch
- Main
- Trunk
- Interceptor ( Largest )
What pipe layout is used in a collection system that needs
to go under a body of water; such as a river? - Answer-
"Inverted Siphon"
Pipes go underneath the body of water connecting
manholes on each side.
, 4|Page
Most important part is that the manhole on the receiving
side must be at a lower elevation than the sending side.
What is the desired velocity in a collection system & what
is the nickname used to describe the speed? - Answer-
Velocity = 2 Feet per Second ( F.P.S. )
Nickname = "Scouring Speed"
What are the 2 main types of electrical phases? - Answer-
Single-Phase ( 2 Wires )
Three-Phase ( 3 or 4 Wires )
What are 3 common chemicals that can be used to correct
an anaerobic digester upset by raising the pH? - Answer--
Calcium Hydroxide ( Quicklime )
- Sodium Bicarbonate
- Sodium Hydroxide
