TEXAS WASTEWATER CLASS C NEWEST ACTUAL EXAM
What device(s) can be used as an emergency shut-off for the drive unit of a circular
clarifier? - ANSWER: Shear Pins
You are the operator-on-duty. The alarm for the fire detector in the Belt Filter Press
Control Room goes off. What type of fire extinguisher would you take to respond to
this alarm? - ANSWER: Class C
When working in an area with two or more floor coverings (for example, grating and
checker-plate), be sure that they are always _____. - ANSWER: Secured together
When working in confined spaces where flammable gases may be present, use only
toolsmade of - ANSWER: A non sparking alloy
A treatment plant should have a valve exercise program in which all plant valves are
exercised (opened and closed) - ANSWER: Once a year
Immediate first aid for burns is to? - ANSWER: Flood with cold water
Recommended personal hygiene practices to minimize the risk of being infected by
wastewater pathogens include - ANSWER: Changing out of your work clothes and
showering before leaving work
What is the best protection against the risk of exposure to infections and disease at a
wastewater plant? - ANSWER: Personal Hygenie
Regarding fire extinguisher training in the workplace. The employer must provide
what? - ANSWER: A written and practiced emergency action plan.
The combination of methane and which other gas can be very combustible? -
ANSWER: Oxygen
In what location of the sewer manhole would methane gas be found? - ANSWER: At
the top
Which type of fire is safe for a pressurized water extinguisher or water hose to be
used on? - ANSWER: Brush
Mixing dry granular chlorine (HTH) with petroleum products can cause which of the
following? - ANSWER: Create a fire or explosive condition
The fusible plugs found on a 150lb cylinders and one-ton chlorinecontainers are
designed to melt at what temperature range? - ANSWER: 158-165 degrees
Fahrenheit
,In the event of a large leak of chlorine is occurring, what is the first action the
operator should take? - ANSWER: Immediately notify local fire and police
departments
A Class C type fire involves? - ANSWER: Electrical equipment
A common fire extinguisher is AB or ABC type. What is the media contained inside
these fire extinguishers? - ANSWER: Dry Powder
This toxic gas impairs one's sense of smell rapidly at high concentrations as it
paralyses the respiratory organs. At lower concentrations it has a rotten egg odor. -
ANSWER: Hydrogen Sulfide Gas
Coliform bacteria are: - ANSWER: More resistant to chlorination than pathogenic
bacteria
Coliform bacteria are: - ANSWER: Indicators
E. Coli results must always be higher or lower than fecal coliform results? - ANSWER:
Lower
Waterborne diseases and illnesses common to the wastewater industryinclude
dysentery, hepatitis, polio, typhoid, and what other disease? - ANSWER: Cholera
How many fusible plugs are in a 1 ton chlorine container? - ANSWER: 6
What is the proper amount of oxygen to enter a confined space? - ANSWER: 19.5% -
23.5%
Which safety procedure can prevent accidental re-energizing of electrical energy
while maintaining a piece of equipment? - ANSWER: Use proper LO/TO procedures
If a leak of liquid chlorine occurs, one part of the liquid chlorine can expand to how
many parts of gaseous chlorine at room temperature and average barometric
pressure? - ANSWER: 457 parts of gas.
Chlorine gas is how many times heavier than air? - ANSWER: 2.5 times
Methane gas is lighter than air - ANSWER: True
A pump's seal water pressure should be set at - ANSWER: 5 to 10 psi more than the
pump operating discharge pressure
What does a gradual increase in the bearing temperature of a centrifugal blower
indicate? - ANSWER: There is a problem with the bearing lubrication or connection
How often should the packing on a gate valve be replaced? - ANSWER: As required
, What is surging in a centrifugal blower? - ANSWER: When the blower's discharge
pressure is less than the aeration system's backpressure
Pumps are often required to bring wastewater into a treatment plant. What types of
pumps are typically used to lift influent wastewater? - ANSWER: Centrifugal
If a centrifugal pump loses its prime after starting, what is the most probable cause?
- ANSWER: Air leaks into the pump through stuffing boxes
The casing surrounding a pump impeller that collects the water discharged by the
impeller is called a __________. - ANSWER: Volute
A _____ is installed on the pump discharge piping to prevent water from flowing
back across a pump when it is off. - ANSWER: Check Valve
Why are check valves used in conjunction with centrifugal pumps? - ANSWER: To
prevent water in the suction line from flowing back into the wetwell
What separates the impeller from the volute and prevents backflow in a centrifugal
pump? - ANSWER: Wear Rings
Cavitation is the formation and collapse of a gas pocket or bubble on the blade of a
pump's impeller. - ANSWER: True
Bar screens must be cleaned frequently to prevent (choose the most correct answer)
- ANSWER: Excess head loss (slowing down the water moving through the pipe)
What is an air-gap device used for? - ANSWER: Backflow prevention
Flow - ANSWER: The amount of fluid to be pumped
Head - ANSWER: The extent or distance to which fluid is to be exported.
The discharge of a centrifugal pump: - ANSWER: Decreases with the increase of
head, and increases with the decrease in head
In a centrifugal pump, leakage is prevented by - ANSWER: Wear rings
Valves should be closed slowly to prevent: - ANSWER: Water Hammer
The purpose of racks or screens is to remove which of the following? - ANSWER:
large solids
Which of the following indicates that the impeller of a centrifugal pump may be
worn or damaged? - ANSWER: Pump is not delivering the design flow
What device(s) can be used as an emergency shut-off for the drive unit of a circular
clarifier? - ANSWER: Shear Pins
You are the operator-on-duty. The alarm for the fire detector in the Belt Filter Press
Control Room goes off. What type of fire extinguisher would you take to respond to
this alarm? - ANSWER: Class C
When working in an area with two or more floor coverings (for example, grating and
checker-plate), be sure that they are always _____. - ANSWER: Secured together
When working in confined spaces where flammable gases may be present, use only
toolsmade of - ANSWER: A non sparking alloy
A treatment plant should have a valve exercise program in which all plant valves are
exercised (opened and closed) - ANSWER: Once a year
Immediate first aid for burns is to? - ANSWER: Flood with cold water
Recommended personal hygiene practices to minimize the risk of being infected by
wastewater pathogens include - ANSWER: Changing out of your work clothes and
showering before leaving work
What is the best protection against the risk of exposure to infections and disease at a
wastewater plant? - ANSWER: Personal Hygenie
Regarding fire extinguisher training in the workplace. The employer must provide
what? - ANSWER: A written and practiced emergency action plan.
The combination of methane and which other gas can be very combustible? -
ANSWER: Oxygen
In what location of the sewer manhole would methane gas be found? - ANSWER: At
the top
Which type of fire is safe for a pressurized water extinguisher or water hose to be
used on? - ANSWER: Brush
Mixing dry granular chlorine (HTH) with petroleum products can cause which of the
following? - ANSWER: Create a fire or explosive condition
The fusible plugs found on a 150lb cylinders and one-ton chlorinecontainers are
designed to melt at what temperature range? - ANSWER: 158-165 degrees
Fahrenheit
,In the event of a large leak of chlorine is occurring, what is the first action the
operator should take? - ANSWER: Immediately notify local fire and police
departments
A Class C type fire involves? - ANSWER: Electrical equipment
A common fire extinguisher is AB or ABC type. What is the media contained inside
these fire extinguishers? - ANSWER: Dry Powder
This toxic gas impairs one's sense of smell rapidly at high concentrations as it
paralyses the respiratory organs. At lower concentrations it has a rotten egg odor. -
ANSWER: Hydrogen Sulfide Gas
Coliform bacteria are: - ANSWER: More resistant to chlorination than pathogenic
bacteria
Coliform bacteria are: - ANSWER: Indicators
E. Coli results must always be higher or lower than fecal coliform results? - ANSWER:
Lower
Waterborne diseases and illnesses common to the wastewater industryinclude
dysentery, hepatitis, polio, typhoid, and what other disease? - ANSWER: Cholera
How many fusible plugs are in a 1 ton chlorine container? - ANSWER: 6
What is the proper amount of oxygen to enter a confined space? - ANSWER: 19.5% -
23.5%
Which safety procedure can prevent accidental re-energizing of electrical energy
while maintaining a piece of equipment? - ANSWER: Use proper LO/TO procedures
If a leak of liquid chlorine occurs, one part of the liquid chlorine can expand to how
many parts of gaseous chlorine at room temperature and average barometric
pressure? - ANSWER: 457 parts of gas.
Chlorine gas is how many times heavier than air? - ANSWER: 2.5 times
Methane gas is lighter than air - ANSWER: True
A pump's seal water pressure should be set at - ANSWER: 5 to 10 psi more than the
pump operating discharge pressure
What does a gradual increase in the bearing temperature of a centrifugal blower
indicate? - ANSWER: There is a problem with the bearing lubrication or connection
How often should the packing on a gate valve be replaced? - ANSWER: As required
, What is surging in a centrifugal blower? - ANSWER: When the blower's discharge
pressure is less than the aeration system's backpressure
Pumps are often required to bring wastewater into a treatment plant. What types of
pumps are typically used to lift influent wastewater? - ANSWER: Centrifugal
If a centrifugal pump loses its prime after starting, what is the most probable cause?
- ANSWER: Air leaks into the pump through stuffing boxes
The casing surrounding a pump impeller that collects the water discharged by the
impeller is called a __________. - ANSWER: Volute
A _____ is installed on the pump discharge piping to prevent water from flowing
back across a pump when it is off. - ANSWER: Check Valve
Why are check valves used in conjunction with centrifugal pumps? - ANSWER: To
prevent water in the suction line from flowing back into the wetwell
What separates the impeller from the volute and prevents backflow in a centrifugal
pump? - ANSWER: Wear Rings
Cavitation is the formation and collapse of a gas pocket or bubble on the blade of a
pump's impeller. - ANSWER: True
Bar screens must be cleaned frequently to prevent (choose the most correct answer)
- ANSWER: Excess head loss (slowing down the water moving through the pipe)
What is an air-gap device used for? - ANSWER: Backflow prevention
Flow - ANSWER: The amount of fluid to be pumped
Head - ANSWER: The extent or distance to which fluid is to be exported.
The discharge of a centrifugal pump: - ANSWER: Decreases with the increase of
head, and increases with the decrease in head
In a centrifugal pump, leakage is prevented by - ANSWER: Wear rings
Valves should be closed slowly to prevent: - ANSWER: Water Hammer
The purpose of racks or screens is to remove which of the following? - ANSWER:
large solids
Which of the following indicates that the impeller of a centrifugal pump may be
worn or damaged? - ANSWER: Pump is not delivering the design flow
