CWEA MECHANICAL TECHNOLOGIST COMPREHENSIVE EXAM SCRIPT COMPLETE
QUESTIONS VERIFIED SOLUTIONS
Question:
Mechanical seal failure.
Answer:
A failure that can occur due to overheating, excessive vibration, and low flow rates.
Question:
Air blower.
Answer:
A device used to supply oxygen to aerobic processes in wastewater treatment.
Question:
Motor maintenance checks.
Answer:
Routine checks that include lubrication of bearings, voltage and current levels, and alignment with
the drive shaft.
Question:
Corrosion prevention in mechanical components.
Answer:
Typically achieved using stainless steel due to its resistance to corrosion.
Question:
,Pump not priming troubleshooting.
Answer:
Checking the pump's discharge valve to ensure it's fully open.
Question:
Cleaning a clogged pump impeller.
Answer:
Recommended to remove and manually clean the impeller with a brush.
Question:
Safety precautions with electrical motors.
Answer:
Ensuring the motor is properly grounded to prevent electrical shock.
Question:
Mechanical strainer function.
Answer:
To filter out solids from liquids in wastewater treatment.
Question:
Mechanical strainers.
Answer:
Mechanical strainers are used to remove large solids and debris from wastewater before it enters
treatment systems, preventing damage to equipment and ensuring smoother operation.
Question:
Oil change interval for gear reducers.
,Answer:
Gear reducers should be serviced according to the manufacturer's guidelines, which often specify an
interval for oil changes, typically between 6 months and 2 years depending on usage.
Question:
Check valve.
Answer:
Check valves allow flow in one direction and automatically close to prevent backflow, protecting
pumps and other equipment from damage.
Question:
Cavitation in pumps.
Answer:
Cavitation occurs when vapor bubbles form in the pump due to low pressure and then collapse,
causing noise, vibration, and potential damage to the pump.
Question:
Replacing bearings in a pump motor.
Answer:
It is crucial to replace bearings with those that match the original specifications to maintain proper
motor function and extend service life.
Question:
First check if a pump motor is not starting.
Answer:
If a pump motor is not starting, the first step should be to check the power supply and ensure
electrical connections are intact and functioning.
, Question:
Variable frequency drive (VFD).
Answer:
A VFD allows for variable speed operation of pumps, which helps optimize energy usage based on
system demand, reducing electricity costs.
Question:
Cast iron.
Answer:
Cast iron is commonly used for pump impellers due to its strength, wear resistance, and ability to
withstand harsh wastewater conditions.
Question:
Sludge conveyor system.
Answer:
Sludge conveyors are used to move accumulated sludge from various treatment processes to the
dewatering area or disposal site.
Question:
Running a pump dry.
Answer:
Running a pump dry can cause severe damage to the pump components (like the seals and bearings),
so it should be turned off as soon as possible.
Question:
Expansion joint.
Answer:
QUESTIONS VERIFIED SOLUTIONS
Question:
Mechanical seal failure.
Answer:
A failure that can occur due to overheating, excessive vibration, and low flow rates.
Question:
Air blower.
Answer:
A device used to supply oxygen to aerobic processes in wastewater treatment.
Question:
Motor maintenance checks.
Answer:
Routine checks that include lubrication of bearings, voltage and current levels, and alignment with
the drive shaft.
Question:
Corrosion prevention in mechanical components.
Answer:
Typically achieved using stainless steel due to its resistance to corrosion.
Question:
,Pump not priming troubleshooting.
Answer:
Checking the pump's discharge valve to ensure it's fully open.
Question:
Cleaning a clogged pump impeller.
Answer:
Recommended to remove and manually clean the impeller with a brush.
Question:
Safety precautions with electrical motors.
Answer:
Ensuring the motor is properly grounded to prevent electrical shock.
Question:
Mechanical strainer function.
Answer:
To filter out solids from liquids in wastewater treatment.
Question:
Mechanical strainers.
Answer:
Mechanical strainers are used to remove large solids and debris from wastewater before it enters
treatment systems, preventing damage to equipment and ensuring smoother operation.
Question:
Oil change interval for gear reducers.
,Answer:
Gear reducers should be serviced according to the manufacturer's guidelines, which often specify an
interval for oil changes, typically between 6 months and 2 years depending on usage.
Question:
Check valve.
Answer:
Check valves allow flow in one direction and automatically close to prevent backflow, protecting
pumps and other equipment from damage.
Question:
Cavitation in pumps.
Answer:
Cavitation occurs when vapor bubbles form in the pump due to low pressure and then collapse,
causing noise, vibration, and potential damage to the pump.
Question:
Replacing bearings in a pump motor.
Answer:
It is crucial to replace bearings with those that match the original specifications to maintain proper
motor function and extend service life.
Question:
First check if a pump motor is not starting.
Answer:
If a pump motor is not starting, the first step should be to check the power supply and ensure
electrical connections are intact and functioning.
, Question:
Variable frequency drive (VFD).
Answer:
A VFD allows for variable speed operation of pumps, which helps optimize energy usage based on
system demand, reducing electricity costs.
Question:
Cast iron.
Answer:
Cast iron is commonly used for pump impellers due to its strength, wear resistance, and ability to
withstand harsh wastewater conditions.
Question:
Sludge conveyor system.
Answer:
Sludge conveyors are used to move accumulated sludge from various treatment processes to the
dewatering area or disposal site.
Question:
Running a pump dry.
Answer:
Running a pump dry can cause severe damage to the pump components (like the seals and bearings),
so it should be turned off as soon as possible.
Question:
Expansion joint.
Answer:
