Variables
Description
What is this formula?
This formula calculates the theoretical chlorine contact time by dividing the effective contact basin volume by the flow rate.
When to use it
Use it when designing or evaluating chlorination systems, disinfection contact chambers, drinking water treatment plants, and wastewater treatment facilities.
Example
Data:
V = 300 m³
Q = 600 m³/h
Formula:
T = V / Q
Substitution:
T = 300 / 600
Result:
T = 0.5 h
T = 30 min
Applications
Water disinfection design, chlorination systems, wastewater treatment, drinking water treatment, regulatory compliance, and process optimization.
Note
Actual contact time is often lower than the theoretical value due to short-circuiting, dead zones, and hydraulic inefficiencies. Regulatory calculations commonly use baffling factors or effective contact times rather than theoretical retention time alone.