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).
The Economic Advantages of Chlorine Gas Disinfection
| Chlorine Gas (100%) | Calcium Hypochlorite (65%) | Sodium Hypochlorite (12.5%) | |
|---|---|---|---|
| Required Equipment |
|
|
|
| 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 |
| Number of 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 to the usage of chlorine gas disinfection.
