Friday, August 04, 2006

What is an Empty Bed Contact Time (EBCT)?

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?"

Our Answer:
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

3 Comments:

Anonymous Anonymous said...

Wow...this is almost like rocket science! Thanks for the info.

1:50 PM  
Anonymous Anonymous said...

thxs for posting EBCT

But how did you get conversion factor, which you shown 7.48 gal/cubic ft.

Because, 7.48 gal/cubic ft = 1.0001=1

so whts meaning of conversionj factor to consider, and if, in which case?

thxs

9:35 AM  
Anonymous Anonymous said...

Actually, 7.48gal/cubic ft = 7.48 and the the reason for C is that V is in cubic feet and Q is in gallons. Because these are two different measurements for volume, the conversion factor is needed for an EBCT in minutes.

2:40 PM  

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