Detention time DT = Volume / Flow (hours if units consistent). If a tank holds 50,000 gallons and the flow is 5,000 gallons per hour, what is the detention time?

Detention time DT = Volume / Flow (hours if units consistent). If a tank holds 50,000 gallons and the flow is 5,000 gallons per hour, what is the detention time?

• A. 5 hours
• B. 10 hours
• C. 0.1 hours
• D. 50 hours

Answer: (B)

Detention time is the time water spends in a tank, calculated by dividing the tank volume by the flow rate. Here, 50,000 gallons in the tank divided by 5,000 gallons per hour gives 10 hours. The units cancel properly (gallons divided by gallons per hour leaves hours), so the detention time is 10 hours. The other numbers would require a different flow or volume.

Detention time is the time water spends in a tank, calculated by dividing the tank volume by the flow rate. Here, 50,000 gallons in the tank divided by 5,000 gallons per hour gives 10 hours. The units cancel properly (gallons divided by gallons per hour leaves hours), so the detention time is 10 hours. The other numbers would require a different flow or volume.