What is the gpd setting for the liquid polymer chemical feeder if the jar tests indicate a dose of 12 mg/L and the flow is 2.5 mil gal/day?

To determine the appropriate gallons per day (gpd) setting for the liquid polymer chemical feeder based on the given jar test results and flow rate, you can follow these steps:

First, convert the flow rate from million gallons per day (mil gal/day) to gallons per day (gpd). Since 1 million gallons is equivalent to 1,000,000 gallons, a flow of 2.5 mil gal/day corresponds to 2.5 × 1,000,000 gpd, which is 2,500,000 gallons per day.

Next, calculate the total dosage required based on the indicated dose from the jar tests, which is 12 milligrams per liter (mg/L). To convert this to gallons, it’s crucial to understand that 1 mg/L is equivalent to 1 pound per million gallons. Thus, a dose of 12 mg/L means that you require 12 pounds of polymer per million gallons treated.

Therefore, for a flow rate of 2.5 million gallons per day:

Total pounds of polymer needed = 12 pounds/million gallons × 2.5 million gallons = 30 pounds per day.

Next, to find the feeder setting in gpd, consider the typical concentration of the