1|Page
CWEA Wastewater Operator Mathematics Exam
Practice Questions And Correct Answers||Verified
Exam!!!|| (Verified Answers) Plus Rationale 2026/2027
Q&A| Instant Download Pdf
A single-piston reciprocating pump has a 6-in diameter
piston with a 6-in length of stroke. If it makes 16 discharge
strokes per minute, the pumping rate is - Answer-12
Calculate the weir loading for a sedimentation tank that
has an outlet weir 480 ft long and a flow of 5 MGD -
Answer-10417 gpd/ft
A settling bason 60 ft long by 20 ft wide and 12 ft deep is
used to treat a flow of 2.4 MGD. What is the detention
time? - Answer-1.1 hours
Calculate the pounds of BOD per day entering a trickling
filter.
Data:
Raw wastewater flow = 1.5 MGD
Raw wastewater BOD = 150 mg/L
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There is a 30% reduction in BOD through primary
treatment - Answer-1,880 lb/day
A plant ran bowers for 24 hours at 5000 cu ft/min. How
many cubic feet of air were required to remove a pound of
BOD per day in the activated sludge system removed
6000 lb BOD? - Answer-1,200
How many pounds of chlorine will be used in 1 day if the
flow is 700,000 gpd and a uniform dose of 1.2 mg/L is
applied? - Answer-7 lb
Determine the gallons of wastewater delivered to a
chemical treatment tank if the pumping rate is 60 gpm for
3 hours. - Answer-10,800 gallons
Find the average for the following temperature readings:
90, 75, 85, 74, 92, and 100 degrees - Answer-86 degrees
A clarifier influent contains 2.31 mg/L chromium with the
effluent discharge containing 0.18 mg/L. Determine the
efficiency. - Answer-92%
,3|Page
Calculate the surface area of an equalization bason 98
feet in diameter and 18 feet deep. - Answer-7539 sq ft
Determine the volume in cubic feet of a reaction basin that
is 24 ft. long, 11 ft. wide, and 5 ft. deep. - Answer-1320 cu
ft
If polymer costs $0.48 per pound and your plant uses 14.8
pounds per day, what is the polymer cost per year? -
Answer-$2593
Calculate the amount of concrete required in cubic yards if
your dimensions are 27 ft by 18 ft by 9 ft. - Answer-162
Compute the lagoons detention time.
Data: Surface area - 6.0 ac
Average depth - 3.0 ft
Average daily flow (influent) - 0.25 MGD
1 ac (area) - 43,560 sq ft
1 cu ft - 7.48 gal - Answer-24 days
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How many pounds of chlorine gas are necessary to treat
4,000,000 gal of wastewater at a dosage of 2 mg/L? -
Answer-67 lb
Your waste water treatment plant serves 1,100 people.
The flow averages 80,000 gpd. The approximate daily flow
contribution per person is - Answer-73 gpd/cap
Over a 4-year period, the hour meter on an instrument air
compressor had the following readings at the end of each
year: first year - 976.3; second year - 1325.8; third year -
2007.1; fourth year 2371.4. How many hours does the
meter show that the compressor ran during the third year?
- Answer-681.3
Calculate pounds of chromium discharged if your plant
flow is 10 MGD and your effluent chromium is 0.14 mg/L. -
Answer-11.68
Determine the detention time of a circular clarifier having a
diameter of 65 ft, a depth of 14 ft, and a flow of 4.6 MGD. -
Answer-1.8 hours
A treatment plant is treating 850,000 gallons of wastewater
daily and the computer total suspended soils of the
CWEA Wastewater Operator Mathematics Exam
Practice Questions And Correct Answers||Verified
Exam!!!|| (Verified Answers) Plus Rationale 2026/2027
Q&A| Instant Download Pdf
A single-piston reciprocating pump has a 6-in diameter
piston with a 6-in length of stroke. If it makes 16 discharge
strokes per minute, the pumping rate is - Answer-12
Calculate the weir loading for a sedimentation tank that
has an outlet weir 480 ft long and a flow of 5 MGD -
Answer-10417 gpd/ft
A settling bason 60 ft long by 20 ft wide and 12 ft deep is
used to treat a flow of 2.4 MGD. What is the detention
time? - Answer-1.1 hours
Calculate the pounds of BOD per day entering a trickling
filter.
Data:
Raw wastewater flow = 1.5 MGD
Raw wastewater BOD = 150 mg/L
,2|Page
There is a 30% reduction in BOD through primary
treatment - Answer-1,880 lb/day
A plant ran bowers for 24 hours at 5000 cu ft/min. How
many cubic feet of air were required to remove a pound of
BOD per day in the activated sludge system removed
6000 lb BOD? - Answer-1,200
How many pounds of chlorine will be used in 1 day if the
flow is 700,000 gpd and a uniform dose of 1.2 mg/L is
applied? - Answer-7 lb
Determine the gallons of wastewater delivered to a
chemical treatment tank if the pumping rate is 60 gpm for
3 hours. - Answer-10,800 gallons
Find the average for the following temperature readings:
90, 75, 85, 74, 92, and 100 degrees - Answer-86 degrees
A clarifier influent contains 2.31 mg/L chromium with the
effluent discharge containing 0.18 mg/L. Determine the
efficiency. - Answer-92%
,3|Page
Calculate the surface area of an equalization bason 98
feet in diameter and 18 feet deep. - Answer-7539 sq ft
Determine the volume in cubic feet of a reaction basin that
is 24 ft. long, 11 ft. wide, and 5 ft. deep. - Answer-1320 cu
ft
If polymer costs $0.48 per pound and your plant uses 14.8
pounds per day, what is the polymer cost per year? -
Answer-$2593
Calculate the amount of concrete required in cubic yards if
your dimensions are 27 ft by 18 ft by 9 ft. - Answer-162
Compute the lagoons detention time.
Data: Surface area - 6.0 ac
Average depth - 3.0 ft
Average daily flow (influent) - 0.25 MGD
1 ac (area) - 43,560 sq ft
1 cu ft - 7.48 gal - Answer-24 days
, 4|Page
How many pounds of chlorine gas are necessary to treat
4,000,000 gal of wastewater at a dosage of 2 mg/L? -
Answer-67 lb
Your waste water treatment plant serves 1,100 people.
The flow averages 80,000 gpd. The approximate daily flow
contribution per person is - Answer-73 gpd/cap
Over a 4-year period, the hour meter on an instrument air
compressor had the following readings at the end of each
year: first year - 976.3; second year - 1325.8; third year -
2007.1; fourth year 2371.4. How many hours does the
meter show that the compressor ran during the third year?
- Answer-681.3
Calculate pounds of chromium discharged if your plant
flow is 10 MGD and your effluent chromium is 0.14 mg/L. -
Answer-11.68
Determine the detention time of a circular clarifier having a
diameter of 65 ft, a depth of 14 ft, and a flow of 4.6 MGD. -
Answer-1.8 hours
A treatment plant is treating 850,000 gallons of wastewater
daily and the computer total suspended soils of the
