WASTEWATER MA LATEST
MUNICIPAL GRADE 4
EXAM QUESTIONS AND
ANSWERS 2026 - 2027
According to OSHA. what is the lowest safe concentration for oxygen-
in-air concentration for humans to breath in order to avoid hazard -
ANSWERS-19.5% oxygen
Which of the following types of pump delivers liquid chemical solutions
the MOST accurately - ANSWERS-Diaphragm
Given the following data, what would most likely cause a chlorinator
problem ?
The chlorine cylinder valve is closed
The ball in the indicator tube drops to zero
The ejector water supply is off
The chlorine supply indicator at the chlorinator shows no supply
The chlorine supply indicator resets after 10 minutes - ANSWERS-The
injector is clogged
END OF
PAGE
1
, WASTEWATER MA LATEST
MUNICIPAL GRADE 4
EXAM QUESTIONS AND
ANSWERS 2026 - 2027
What is the required water horsepower for a centrifugal pump pumping
200 gallons per minute against 40 feet total dynamic head ? -
ANSWERS-2.0 HP
In a centrifugal pump, internal circulation is prevented by - ANSWERS-
Impellers
Where would an operator expect to find the highest concentration of
methane in a manhole - ANSWERS-Near the top
What is a V-notch weir BEST suited for measuring - ANSWERS-Small
constant flows
A sample of plant efflent must be tested for ph within - ANSWERS-15
minutes
How should acid and water be mixed in a laboratory ? - ANSWERS-
Pour acid into water
END OF
PAGE
2
, WASTEWATER MA LATEST
MUNICIPAL GRADE 4
EXAM QUESTIONS AND
ANSWERS 2026 - 2027
What is the best material to use to seed BOD water ? - ANSWERS-
Fresh settled domestic wastewater
An operator should get out of a manhole as soon as s/he feels -
ANSWERS-Drowsy
How can the thickness of the floating sludge blanket in a dissolved air
floation unit be increased - ANSWERS-Decrease the speed of the
surface sludge scrapers
Wastewater is the same as:
A. Rain
B. Soil
C. Sewage
D. Condensation - ANSWERS-C. sewage
END OF
PAGE
3
MUNICIPAL GRADE 4
EXAM QUESTIONS AND
ANSWERS 2026 - 2027
According to OSHA. what is the lowest safe concentration for oxygen-
in-air concentration for humans to breath in order to avoid hazard -
ANSWERS-19.5% oxygen
Which of the following types of pump delivers liquid chemical solutions
the MOST accurately - ANSWERS-Diaphragm
Given the following data, what would most likely cause a chlorinator
problem ?
The chlorine cylinder valve is closed
The ball in the indicator tube drops to zero
The ejector water supply is off
The chlorine supply indicator at the chlorinator shows no supply
The chlorine supply indicator resets after 10 minutes - ANSWERS-The
injector is clogged
END OF
PAGE
1
, WASTEWATER MA LATEST
MUNICIPAL GRADE 4
EXAM QUESTIONS AND
ANSWERS 2026 - 2027
What is the required water horsepower for a centrifugal pump pumping
200 gallons per minute against 40 feet total dynamic head ? -
ANSWERS-2.0 HP
In a centrifugal pump, internal circulation is prevented by - ANSWERS-
Impellers
Where would an operator expect to find the highest concentration of
methane in a manhole - ANSWERS-Near the top
What is a V-notch weir BEST suited for measuring - ANSWERS-Small
constant flows
A sample of plant efflent must be tested for ph within - ANSWERS-15
minutes
How should acid and water be mixed in a laboratory ? - ANSWERS-
Pour acid into water
END OF
PAGE
2
, WASTEWATER MA LATEST
MUNICIPAL GRADE 4
EXAM QUESTIONS AND
ANSWERS 2026 - 2027
What is the best material to use to seed BOD water ? - ANSWERS-
Fresh settled domestic wastewater
An operator should get out of a manhole as soon as s/he feels -
ANSWERS-Drowsy
How can the thickness of the floating sludge blanket in a dissolved air
floation unit be increased - ANSWERS-Decrease the speed of the
surface sludge scrapers
Wastewater is the same as:
A. Rain
B. Soil
C. Sewage
D. Condensation - ANSWERS-C. sewage
END OF
PAGE
3
