How to Calculate Chlorine Dose

Water treatment plants convert fresh water into potable drinking water, removing contaminants and killing bacteria that are harmful when ingested. A common method of cleaning the water being processed is with the use of chlorine. When using chlorine in the water it is important to carefully monitor the amount used -- to ensure enough chlorine is infused to kill harmful bacteria -- while not over-chlorinating the water and making it dangerous. This is performed by applying a basic formula to the treatment facility's water flow data.

Determining Pounds Per Day

    Check the flow rate of the facility in million gallons per day (MGD). For example, a facility that processes 1,500,000 gallons of water per day, the MGD glow is 1.5.

    Multiply the MGD by 8.34 lbs per gallon. In the example, the result would be 12.51.

    Multiply the result by the desired concentration of chlorine in milligrams per liter. For the example, a desired concentration of 4 milligrams per liter would be multiplied by 12.51 to yield a result of 50 pounds of chlorine per day.

Finding the Concentration of a Solution

    Check the flow rate of the facility in million gallons per day (MGD). For example, a facility that processes 3,000,000 gallons of water per day, the MGD glow is 3.

    Determine the amount of chlorine being added to the water each day. For the example, assume the facility is using 100 pounds of chlorine per day.

    Divide the daily chlorine input by the MGD flow of the facility. In the example, the result would yield 33.33.

    Divide the result by 8.34 pounds per gallon to find the chlorine concentration. In the example, the concentration is 4 milligrams per liter.

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