A cooling water system contains 12,000 gallons of water. How much biocide is needed for a dosage of 25 ppm?

To determine the amount of biocide needed for a cooling water system with a dosage of 25 parts per million (ppm), we first need to understand what ppm means in this context. One ppm is equivalent to one milligram of substance per liter of water (or one part of solute per million parts of solution).

Given that there are 12,000 gallons of water in the cooling system, we can convert this volume into liters, since the ppm calculation usually requires the volume in liters. There are approximately 3.78541 liters in a gallon, so:

12,000 gallons x 3.78541 liters/gallon = 45,424.92 liters (approximately).

Next, we convert ppm to a mass based on the total volume in liters. For a dosage of 25 ppm:

25 ppm = 25 mg/L

Now, multiply the concentration by the volume of the cooling water system in liters:

25 mg/L x 45,424.92 L ≈ 1,135,622.94 mg.

To convert milligrams to pounds (since there are 454,000 mg in a pound):

1,135,622.94 mg ÷ 454,000 mg/pound ≈ 2.