Question 9020 of 234 · California Wastewater Operator Exam
A pond is 5 acres in area with an average depth of 4 ft. Flow is 0.25 MGD. What is the detention time in days? (1 acre-ft = 325,851 gal)
Exactly one answer is correct.
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Correct answer to question 9020
- D: 26.1 days
Explanation
Volume = 5 x 4 = 20 acre-ft x 325,851 = 6,517,020 gal. Detention time = 6,517,020 / 250,000 = 26.1 days. Dividing acre-feet directly by MGD, or leaving out the conversion to gallons, gives wrong results.
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