The Economic Advantages of Chlorine Gas Disinfection

The following table clarifies the economic advantages of gas chlorination disinfection by comparing the necessary capital investment, chemical costs, and personnel requirements to treat one million gallons per day (1 MGD) of drinking water to a concentration of one PPM (part of chlorine per million parts of water, which is equivalent to one mg/L).

 

  Chlorine Gas
(100%)
Calcium Hypochlorite
(65%)
Sodium Hypochlorite
(12.5%)
Required Equipment (1)Hydro Model 500 chlorinator
(1)Booster pump
(1)150lb. chlorine cylinder
(1)Metering Pump
(1)50 gal. tank with lid
(1)Agitator
(1)Level switch
(1)Metering Pump
(1)50 gal. tank with lid
(1)Level switch
Initial Capital Investment
$1,990.00
$1,186.00
$987.00
Media Quantity Required per Year 3,030 pounds 4,661 pounds 2,920 gallons (app. 24,344 pounds)
Chemical Cost per Media Unit * $0.93/pound $2.00/pound $2.09/gallon
Chemical Cost per Year $2,817.90 $9,322.00 $6,102.00
# Days Between Media Refill 18 app. 7 app. 6
* Costs vary with geographic location.

 

Admittedly the initial capital investment for a chlorine gas system is slightly higher than for hypochlorite treatment, however the savings in chemical cost far outweighs the equipment costs, just in the first year. In addition, the personnel oversight required for a hypochlorite system is greater and could be a cause of problems over weekends or holidays.

Besides these economic advantages there are also considerable practical advantages for the usage of chlorine gas disinfection.