Detention Time Calculator

Your details

Select the treatment unit to compare your result to typical design ranges.
Total liquid volume in the basin or tank.
gal
Volumetric flow rate entering the basin.
gpm
Real basins have stagnant corners and short-circuit paths. A dead-zone factor reduces effective volume to give a more realistic estimate.
Detention timeWithin typical range
150min

Theoretical detention time: Volume / Flow rate

Detention time (hours)2.5hr
Detention time (days)0.1042days
Typical range min90min
Typical range max150min
Volume (gallons)150,000gal
Flow rate (gpm)1,000gpm
Design statusWithin typical design range
Theoretical DT (min)150
Effective DT (min)-

Detention time: 2.50 hr

  • Theoretical detention time is 2.50 hr (150.00 min, 2.500 hr, 0.1042 days).
  • The result falls within the typical design range of 1.50 hr to 2.50 hr for a Primary clarifier / sedimentation.
  • Detention time is a theoretical value based on plug-flow assumptions. Real basins short-circuit due to dead zones, density currents, and inlet/outlet geometry.

Next stepUse tracer studies or computational fluid dynamics to verify actual hydraulic residence time in critical applications such as disinfection contact chambers.

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