If you review your facility’s water bill, you will notice that you are charged a “Sewer Fee” that is based on the amount of incoming water supplied by your water provider.  By default, the provider assumes that the amount of water sent down the drain to the sewer is the same as the amount of incoming water as measured by the water meter.  For Cooling Towers, this is absolutely not the case because much of the water supplied to the cooling tower evaporates as part of the cooling process (often 50% or more).  Therefore, the water company is charging you a Sewer Fee for the water that evaporates.

Why pay a Sewer Fee for water that does not go down the sewer?

For most companies that are using Cooling Towers, the water provider will issue a credit for a portion of the Sewer Fee, if log-books are maintained to document the amount of water that flows into a cooling tower and the amount of water that is sent down the drain.  This can be done by installing flow meters on the inlet and bleed-off lines of the Cooling Tower.  If the amount of water that is supplied to a Cooling Tower and the amount that actually goes to drain, is recorded, it is then a simple math exercise to calculate the amount of water that has evaporated.  This can be then used to determine the credit amount that is due.

The following example demonstrates the savings that can be achieved by monitoring the make-up water and bleed-off water from a Cooling Tower.

EXAMPLE OF POSSIBLE EVAPORATION CREDIT or SEWER CREDIT

System Tonnage
200
Circulation Rate
600 gpm
Cycles
3
Hours per Day
24
Days per Year
365
Load Factor
60%
Evaporation Rate
5,184 Gallons per Day
Bleed-off Rate
2,592 Gallons per Day
Make-up Rate
7,776 Gallons per Day
Sewer Costs
$0.62/100 cu ft = $0.83/1000 gal
Sewer Reduction
5,184 gpd x 365 days = 1,892,169 gpy
Yearly Savings
$1,570
Water Meter Cost
$ 375.00 X 2 = $ 750.00
Water Meter Payback Period
151 Days
On-Going Savings
$ 1,570.00 Annually

 

For more information about Sewer Fee Credits, or for other money saving ideas from Aqua Clear, please call or e-mail us today.