What term defines the time required for a small amount of water to pass through a tank at a given flow rate?

What term defines the time required for a small amount of water to pass through a tank at a given flow rate?

• A. Passage time
• B. Detention time
• C. Residence time
• D. Contact time

Answer: (B)

Detention time is the amount of time water spends in a tank as it flows from inlet to outlet at a given flow rate. It’s calculated from the tank’s volume divided by the flow rate (t = V/Q). This directly matches the idea of “the time required for a small amount of water to pass through a tank” because you’re measuring how long that water parcel stays in the tank before exiting. This term is the standard way engineers describe how long treatment processes have to act inside the tank, and it helps in sizing and assessing performance. For example, a 5,000-gallon tank with a flow of 50 gpm has a detention time of 100 minutes. Residence time is a closely related concept, but detention time is the common term used specifically for the time water spends in a tank. Contact time refers to how long water is in contact with a disinfectant or treatment media, not the overall transit through the tank. Passage time isn’t a standard term in this context.

Detention time is the amount of time water spends in a tank as it flows from inlet to outlet at a given flow rate. It’s calculated from the tank’s volume divided by the flow rate (t = V/Q). This directly matches the idea of “the time required for a small amount of water to pass through a tank” because you’re measuring how long that water parcel stays in the tank before exiting.

This term is the standard way engineers describe how long treatment processes have to act inside the tank, and it helps in sizing and assessing performance. For example, a 5,000-gallon tank with a flow of 50 gpm has a detention time of 100 minutes.

Residence time is a closely related concept, but detention time is the common term used specifically for the time water spends in a tank. Contact time refers to how long water is in contact with a disinfectant or treatment media, not the overall transit through the tank. Passage time isn’t a standard term in this context.