Water treatment involves seven (7) steps:
1. Intake â€“ Large particles such as logs, sticks, plants and fishes are screened out as the water is drawn into the treatment plant from a river, lake or other surface source. If the source is groundwater, the â€śscreeningâ€ť is done by nature as the water travels under the surface of the earth.
2. Pre-treatment- Chlorine and other chemicals, such as alum or lime, are added to the water to help remove impurities and destroy any bad taste or odor. Sometimes chemicals are included to remove excess minerals that make the waterâ€śhardâ€ť or cause rust to form.
3. Mixing â€“ The water is then mixed rapidly to distribute the chemicals evenly.
4. Coagulation and Flocculation - The water is sent into a large basin where the chemicals cling to the impurities in the water (coagulation), causing them to form larger heavier particles called floc. These larger particles settle to the bottom of the basin so that chemicals and impurities can both be removed from the water.
5. Filtration - From the basin, where the floc settles (sedimentation basin) the water continues on its trip through the filters. Layers of sand, gravel and sometimes hard coal (anthracite) are used to remove any other impurities that are left in the water. Another filter may be used to remove toxic organic substances. As the water passes through this layer, certain impurities stick to the filter material. This is called adsorption.
6. Chlorination â€“ Now that everything has been removed from the water, a small amount of chlorine is added to keep the water from developing bacteria as it travels to you. The amount of chlorine is carefully measured to be the lowest possible amount needed to keep the water free of germs. In some places fluoride is also added. It has been found to help prevent tooth decay. Some natural water sources already contain fluoride so this step is not always included.
7. Distribution â€“ Out comes the sparkling water! It may be stored in a reservoir or tank ready for you to use. It travels through large pipes called mains to where it is needed.
Water is life! Do not waste it!