WASTEWATER CLASS 4 Exam Questions
And 100% Verified Answers | Latest
2025/ 2026 Update | Graded A+
How many minutes are in a day? - CORRECT ANSWER-1,440
If a math formula answer is normally in hours, but the question is asking
for minutes, multiply by 1440 instead of 24
Write out the entire Ohm's Law formula, including the units, and the
properties they measure. - CORRECT ANSWER-Amps (Current) = Volts
(Pressure) / Ohm's (Resistance)
Your plant is discharging 1.28 MGD at the outfall. The BOD
concentration in your discharge is 47 mg/L. What is the quantity of BOD
discharged in pounds per day? - CORRECT ANSWER-502 lbs/day
Solution:
,Multiply flow in MGD x BOD concentration, then multiply it by 8.34 to
convert gallons into pounds, since that is the unit they want.
1.28 x 47 x 8.34 = 501.73
Based upon the available data, what change should an operator make
to achieve the optimum organic loading?
Tanks available: 3
Tanks in service: 2
BOD concentration: 176 mg/L
Flow: 6.5 MGD
Tank diameter: 100 ft
Tank depth: 6 ft
The design organic loading rate is 200-300 lbs/1,000 cubic feet. -
CORRECT ANSWER-176 x 6.5 x 8.34 x .785 x 100 x 100 x 6 x 2
tanks= 101
176 x 6.5 x 8.34 x .785 x 100 x 100 x 6 x 1 tank= 203
, Take a tank out of service so that there is only one tank in service. 203 is
within design rate.
Your aeration tank has the following protozoa populations by percent:
Stalked Ciliates 20%
Nematodes: 20%
Rotifers: 60%
What action do you need to take? - CORRECT ANSWER-Increase WAS
You have two tanks that are different shapes, but have the same surface
area at the bottom. Both tanks contain the same volume of water.
Which tank, if any, has a higher pressure at the bottom? - CORRECT
ANSWER-They will both have THE SAME pressure at the bottom of the
tank due to the hydrostatic paradox
Which chemical will cause a decrease in pH? - CORRECT ANSWER-
Sulfuric acid
And 100% Verified Answers | Latest
2025/ 2026 Update | Graded A+
How many minutes are in a day? - CORRECT ANSWER-1,440
If a math formula answer is normally in hours, but the question is asking
for minutes, multiply by 1440 instead of 24
Write out the entire Ohm's Law formula, including the units, and the
properties they measure. - CORRECT ANSWER-Amps (Current) = Volts
(Pressure) / Ohm's (Resistance)
Your plant is discharging 1.28 MGD at the outfall. The BOD
concentration in your discharge is 47 mg/L. What is the quantity of BOD
discharged in pounds per day? - CORRECT ANSWER-502 lbs/day
Solution:
,Multiply flow in MGD x BOD concentration, then multiply it by 8.34 to
convert gallons into pounds, since that is the unit they want.
1.28 x 47 x 8.34 = 501.73
Based upon the available data, what change should an operator make
to achieve the optimum organic loading?
Tanks available: 3
Tanks in service: 2
BOD concentration: 176 mg/L
Flow: 6.5 MGD
Tank diameter: 100 ft
Tank depth: 6 ft
The design organic loading rate is 200-300 lbs/1,000 cubic feet. -
CORRECT ANSWER-176 x 6.5 x 8.34 x .785 x 100 x 100 x 6 x 2
tanks= 101
176 x 6.5 x 8.34 x .785 x 100 x 100 x 6 x 1 tank= 203
, Take a tank out of service so that there is only one tank in service. 203 is
within design rate.
Your aeration tank has the following protozoa populations by percent:
Stalked Ciliates 20%
Nematodes: 20%
Rotifers: 60%
What action do you need to take? - CORRECT ANSWER-Increase WAS
You have two tanks that are different shapes, but have the same surface
area at the bottom. Both tanks contain the same volume of water.
Which tank, if any, has a higher pressure at the bottom? - CORRECT
ANSWER-They will both have THE SAME pressure at the bottom of the
tank due to the hydrostatic paradox
Which chemical will cause a decrease in pH? - CORRECT ANSWER-
Sulfuric acid
