ABC Wastewater collection Level 3 Exam
Questions with Correct Solutions
Already Graded A+!!!Updated
2025/2026 New Syllabus Exam
Preparation Material<<LATEST
VERSION>>
The specific gravity standard for gases is
A. water vapor at 100°C
B. air
C. oxygen
D. nitrogen - ANSWER ✓ B. air
Turbidity in wastewater is caused by
A. color
B. dissolved calcium
C. hardness
D. finely divided suspended material - ANSWER ✓ D. finely divided suspended
material
The gas most commonly associated with septic wastewater is
A. carbon dioxide
B. carbon monoxide
C. hydrogen sulfide
D. methane - ANSWER ✓ C. hydrogen sulfide
The standard for gases has a density of
A. 1.00 g/L
B. 1.13 g/L
C. 1.23 g/L
D. 1.29 g/L - ANSWER ✓ D. 1.29 g/L
How many steps are there in coagulation?
,A. three steps
B. four steps
C. five steps
D. six steps - ANSWER ✓ A. three steps
Low-temperature water can be compensated for when using alum by
A. increasing the pH
B. decreasing the pH
C. increasing the alum dosage
D. decreasing the alum dosage - ANSWER ✓ C. increasing the alum dosage
When an electrolyte is dissolved in water to form an ion, the ion is said to be
A. dissociated
B. ionized
C. hydrated
D. hydrolyzed - ANSWER ✓ A. dissociated
Which one of the following species is ozone?
A. O₂⁺³
B. NO₂
C. O₃
D. N₂O - ANSWER ✓ C. O₃
Which laboratory glassware can be used to heat liquids in an open flame?
A. flasks
B. graduated cylinders
C. volumetric flasks
D. burettes - ANSWER ✓ A. flasks
When inserting glass tubing into rubber hose or stoppers, never use _______ for
lubrication.
A. oil
B. flame polishing
C. water
D. lubricating jelly - ANSWER ✓ A. oil
Electrical units operating in areas exposed to flammable vapors should
A. be removed and reinstalled in a separate room
B. be housed in a tightly sealed container
,C. be double-insulated
D. be explosion-proof - ANSWER ✓ D. be explosion-proof
Usually, what is the percent accuracy of a graduated cylinder ad burette?
A. 1%
B. 1.5%
C. 0.5 and 1%, respectively
D. 1% and 0.5%, respectively - ANSWER ✓ A. 1%
The clarity of a trickling filter's effluent is considered good when the Secchi disk
can read at a level of
A. 1 ft
B. 2 ft
C. 3 ft
D. 4 ft - ANSWER ✓ C. 3 ft
The clarity of the effluent from an activated sludge process is considered good
when the Secchi disk can be read at a level of
A. 3 ft
B. 4 ft
C. 5 ft
D. 6 ft - ANSWER ✓ D. 6 ft
How many cubic meters per second in 10 MGD?
A. 0.44
B. 1.44
C. 4.73
D. 24.62 - ANSWER ✓ A. 0.44
Mechanical ventilation of a lift station is required to
A. lower temperatures to reduce proportion of hydrogen sulfide
B. reduce chlorine demand
C. reduce corrosion
D. increase DO in raw wastewater - ANSWER ✓ C. reduce corrosion
A wet well probe is usually used for ________ determination(s) of level.
A. approximate
B. dual point
C. continuous
, D. single point - ANSWER ✓ D. single point
A pump is delivering at less than the expected rate of discharge. Which of the
causes listed below is incorrect?
A. speed of motor too low
B. pump not primed
C. impeller clogged
D. discharge head too low - ANSWER ✓ D. discharge head too low
Metal pipes often fail because of
A. back siphonage
B. browning movement
C. galvanic action
D. reverse osmosis - ANSWER ✓ C. galvanic action
When a fire hydrant is operated, it should be
A. just opened enough to have a flow
B. opened fully
C. opened halfway
D. regulated to flow required - ANSWER ✓ B. opened fully
If the pump bearings on horizontal centrifugal pumps are over lubricated, the most
important effect is that the extra lubricant
A. will result in smoother and more efficient operation of the pump
B. will not make any difference in the operation of the pump
C. will be wasted
D. shaft or shaft sleeve will be damaged - ANSWER ✓ D. shaft or shaft sleeve will
be damaged
If packing is not maintained properly,
A. cavitation damage will result
B. impeller will corrode
C. loss of suction due to air being allowed to enter pump
D. shaft or shaft sleeve will be damaged - ANSWER ✓ C. loss of suction due to air
being allowed to enter pump
Air flow through a trickling filter when the influent is warmer than the air
temperature is
A. upward through the filter
Questions with Correct Solutions
Already Graded A+!!!Updated
2025/2026 New Syllabus Exam
Preparation Material<<LATEST
VERSION>>
The specific gravity standard for gases is
A. water vapor at 100°C
B. air
C. oxygen
D. nitrogen - ANSWER ✓ B. air
Turbidity in wastewater is caused by
A. color
B. dissolved calcium
C. hardness
D. finely divided suspended material - ANSWER ✓ D. finely divided suspended
material
The gas most commonly associated with septic wastewater is
A. carbon dioxide
B. carbon monoxide
C. hydrogen sulfide
D. methane - ANSWER ✓ C. hydrogen sulfide
The standard for gases has a density of
A. 1.00 g/L
B. 1.13 g/L
C. 1.23 g/L
D. 1.29 g/L - ANSWER ✓ D. 1.29 g/L
How many steps are there in coagulation?
,A. three steps
B. four steps
C. five steps
D. six steps - ANSWER ✓ A. three steps
Low-temperature water can be compensated for when using alum by
A. increasing the pH
B. decreasing the pH
C. increasing the alum dosage
D. decreasing the alum dosage - ANSWER ✓ C. increasing the alum dosage
When an electrolyte is dissolved in water to form an ion, the ion is said to be
A. dissociated
B. ionized
C. hydrated
D. hydrolyzed - ANSWER ✓ A. dissociated
Which one of the following species is ozone?
A. O₂⁺³
B. NO₂
C. O₃
D. N₂O - ANSWER ✓ C. O₃
Which laboratory glassware can be used to heat liquids in an open flame?
A. flasks
B. graduated cylinders
C. volumetric flasks
D. burettes - ANSWER ✓ A. flasks
When inserting glass tubing into rubber hose or stoppers, never use _______ for
lubrication.
A. oil
B. flame polishing
C. water
D. lubricating jelly - ANSWER ✓ A. oil
Electrical units operating in areas exposed to flammable vapors should
A. be removed and reinstalled in a separate room
B. be housed in a tightly sealed container
,C. be double-insulated
D. be explosion-proof - ANSWER ✓ D. be explosion-proof
Usually, what is the percent accuracy of a graduated cylinder ad burette?
A. 1%
B. 1.5%
C. 0.5 and 1%, respectively
D. 1% and 0.5%, respectively - ANSWER ✓ A. 1%
The clarity of a trickling filter's effluent is considered good when the Secchi disk
can read at a level of
A. 1 ft
B. 2 ft
C. 3 ft
D. 4 ft - ANSWER ✓ C. 3 ft
The clarity of the effluent from an activated sludge process is considered good
when the Secchi disk can be read at a level of
A. 3 ft
B. 4 ft
C. 5 ft
D. 6 ft - ANSWER ✓ D. 6 ft
How many cubic meters per second in 10 MGD?
A. 0.44
B. 1.44
C. 4.73
D. 24.62 - ANSWER ✓ A. 0.44
Mechanical ventilation of a lift station is required to
A. lower temperatures to reduce proportion of hydrogen sulfide
B. reduce chlorine demand
C. reduce corrosion
D. increase DO in raw wastewater - ANSWER ✓ C. reduce corrosion
A wet well probe is usually used for ________ determination(s) of level.
A. approximate
B. dual point
C. continuous
, D. single point - ANSWER ✓ D. single point
A pump is delivering at less than the expected rate of discharge. Which of the
causes listed below is incorrect?
A. speed of motor too low
B. pump not primed
C. impeller clogged
D. discharge head too low - ANSWER ✓ D. discharge head too low
Metal pipes often fail because of
A. back siphonage
B. browning movement
C. galvanic action
D. reverse osmosis - ANSWER ✓ C. galvanic action
When a fire hydrant is operated, it should be
A. just opened enough to have a flow
B. opened fully
C. opened halfway
D. regulated to flow required - ANSWER ✓ B. opened fully
If the pump bearings on horizontal centrifugal pumps are over lubricated, the most
important effect is that the extra lubricant
A. will result in smoother and more efficient operation of the pump
B. will not make any difference in the operation of the pump
C. will be wasted
D. shaft or shaft sleeve will be damaged - ANSWER ✓ D. shaft or shaft sleeve will
be damaged
If packing is not maintained properly,
A. cavitation damage will result
B. impeller will corrode
C. loss of suction due to air being allowed to enter pump
D. shaft or shaft sleeve will be damaged - ANSWER ✓ C. loss of suction due to air
being allowed to enter pump
Air flow through a trickling filter when the influent is warmer than the air
temperature is
A. upward through the filter
