Drinking Water Chlorination
The U.S. Centers for Disease Control and Prevention (CDC) has credited the chlorination of drinking water with helping to control infectious diseases and increasing life expectancy by nearly 30 years since 1900.
About the Treatment Process
After water from Arcadia Lake is pumped to the plant, the following treatment processes are utilized:
- Screen building - Screens remove leaves, sticks, fish, and other large debris.
- Air stripping - Aeration removes certain dissolved gases in the water. It is also used to increase the water’s dissolved oxygen content, which is the first step in the removal of iron and manganese.
- Pre-ozone - Ozone disinfects without the by-products produced with chlorine, removing color, odor, and taste. It also oxidizes iron, manganese, sulfide, and organics.
- Flocculation / clarifiers - This process gathers together the fine, light particles to form larger particles that will not readily settle or filter out of the water. The floc then settles out the larger particles. Arcadia Lake raw water quality has historically been good enough to allow Edmond to forego this system’s use.
- Chemical building - Pebble-quick lime is mixed with the water to form calcium hydroxide for softening purposes. Polymer is added as a coagulant aid.
- Solids contact clarifiers - These allow the lime and other solids to settle out of the water after the hardness is reduced.
- Post-ozone - This process is the same as the pre-ozone process.
- Carbon Dioxide-recarbonation - This process, which is especially effective in lime-softened water, is used to lower the pH and alkalinity.
- Mixed-media filters - Filtration is the process of passing water through material, such as sand, coal, granulated carbon, and / or other substances to trap and remove particles from the water.
- Granulated Activated Carbon (GAC) Filtration - GAC filtration removes many types of organic compounds, including those that can form potentially harmful byproducts after chlorination. The process removes synthetic organic compounds such as solvents, cleaning compounds, insecticides and herbicides
- Chlorination - Chlorination is the final process of treatment for the water from the water plant and is also used to treat water from some of the water wells. Chlorine has been used in municipal water systems for more than 100 years and is the choice of water treatment experts because of its superiority as a residual disinfectant.