After you determine the optimum ppm dosage from the jar tests, you will have to calculate your pounds/hr or pounds/day dosage in the water flow to be treated.
Water flow: GPM × 60 = GPH or GPM × 1,440 = GPD
GPH × 8.34 = lbs. of water/hr or GPD × 8.34 = lbs. of water/day
Remember that ppm (or parts/million parts) is the same as pounds/million pounds. As an example, if you want to treat a 1,000 GPM of water flow at 5 ppm, then:
Note that in the second equation above that 1,440 × 8.34 ≈ 12,000.
Pounds of product/day = flow rate × ppm product dosage:
If the specific gravity of the polymer is 1.12 this means it is 1.12 times the weight of water, which is 8.34 pounds/gallon. Therefore, this hypothetical polymer weighs:
Since 1.0 U.S. gallon = 3.785 liters, then 0.27 gals/hr × 3785 = 1,022 mLs/hr
But all of the above is based on neat polymer and since you are going to dilute the polymer before addition to the system you will have to take the solution concentration into consideration.
You have made up a polymer solution in a day tank at 0.5 percent. This means that the polymer has been diluted 200×. Your application rate of the diluted polymer must be 200 times the gallon or mL figure given above in order to have the application rate in neat polymer, as previously calculated.
The following should be considered after you have completed the jar testing protocol and have determined the optimum program:
The jar test is intended to simulate the coagulation and flocculation process in your plant. Consequently, designing a jar test procedure to match conditions in your plant takes a little thought and practice. However, when you have developed the proper routine and then properly applied the results, you will be producing the best water possible at the lowest cost.
This completes the discussion on jar testing procedures.