We receive many questions on calculating the Empty Bed Contact Time as follows: "How do I calculate the "Empty Bed Contact Time" for sizing my carbon bed?"
Calculating the Empty Bed Contact Time, EBCT, is fairly easy to do once you know that the EBCT has the units of time, and usually presented in minutes. You need to know the volume of the carbon bed in your vessel and the flow rate.
Just watch to be certain your units are consistent.
For the units commonly used in the United States:
V = Carbon Bed Volume (cubic feet)
Q = Flow Rate (gpm)
C = Conversion Factor (7.48 gallons/cubic foot)
EBCT= (V x C )/ Q
The EBCT for some common contaminants are:
Chlorine = 2 minutes
VOC's = 7 minutes
Hydrogen Sulfide = 4 minutes