Detention Time
Detention time = volume / flow in min, hr, days; pass/fail vs target.
Example
You enter
- Tank volume (gal) 50000
- Flow (GPM) 350
- Target (min, optional) 120
You get
- Minutes 142.857
- Hours 2.381
- Pass target PASS
Details, formula, and sources
Detention time = volume / flow. Used for chlorine contact (CT for Giardia / virus inactivation per EPA SWTR), flocculation, sedimentation. CT = concentration (mg/L) × T_10 contact time (min).
EPA Surface Water Treatment Rule (SWTR) 40 CFR 141 Subpart H by section. EPA Disinfection Profiling and Benchmarking Guidance Manual by name.
40 CFR 141 free at ecfr.gov. EPA guidance manual free at epa.gov.
Estimate. Operator of record and primacy agency govern.
Field names used by the API: tank_volume_gal, flow_gpm, target_minutes, minutes, hours, pass_target
- Plug-flow assumption T_10 ≈ 0.5-0.7 × theoretical detention time unless user supplies a tracer-study valueEPA Disinfection Profiling Guidance