Date: Monday, May 11 th 2015 Topic: Water Purification Objective: To recognize the stages of it.

Stages of Water Purification Process The following describes the basic steps used to make the water from our lakes, streams, rivers, and reservoirs safe to drink. Having an adequate, clean supply of water in our community ensures:  that everyone has safe water to drink,  that businesses have the water necessary for commerce, and  that the community has water available for fire protection.

 1. Source: It is important that the sources we use for our water supply are good and clean and are readily available in an adequate amount.  2. Treatment: Treatment techniques remove soil and dirt, bacteria, viruses, and parasites, and chemical impurities. The steps include coagulation, flocculation, sedimentation, filtration, and disinfection.  3. Distribution: is the system of pipes that allows water to travel from the drinking water treatment plant to the homes and businesses in your community. It’s made up of pipes, pumps, valves, storage tanks, fire hydrants, and meters.

 Coagulation and Flocculation: Gentle mixing of the water and treatment chemicals causes the impurities and particles to form larger floc particles. Chemicals commonly used for this process include aluminum sulfate (alum), ferric chloride, and synthetic polymers.  Sedimentation: The particles that are formed through coagulation and flocculation become increasingly larger and eventually settle out of the water in large sedimentation basins.  Filtration: After sedimentation, the clarified water is passed through filters to remove particles of dirt, algae, and harmful bacteria and parasites. Filters can be made from sand, gravel, coal, or granular activated carbon.

 Disinfection: Disease-causing bacteria, viruses, and parasites are destroyed by disinfection. Chlorine and chlorine containing compounds are typically used for disinfection purposes. New disinfection technologies may also use ultraviolet light and ozone.  Solids Removal: Solids that settle out of the water are removed to drying lagoons or sludge presses for dewatering.