hydraulic retention tiem calculator
Free calculate hydraulic retention time (hrt) for wastewater treatment, bioreactors, and environmental engineering.
Enter System Data
ratio
Optional - recirculation flow ratio
mL/g
Optional - for sludge settling
Optional - biomass concentration
Results
Enter system data to calculate HRT
Hydraulic Retention Time Formula
Basic HRT Formula
HRT = V / Q
- • HRT = Hydraulic retention time
- • V = Reactor volume
- • Q = Flow rate
- • Units: time (hours, days)
- • Also called detention time
With Recirculation
HRT = V / (Q × (1 + R))
- • R = Recirculation ratio
- • Effective flow rate increases
- • HRT decreases with recirculation
- • Used in trickling filters
- • Improves treatment efficiency