Water from the Lake Michigan pumping station is sent to the beginning of the treatment process where the first step in treatment is the addition of an aluminum base coagulant. This starts the coagulation process.
1) Coagulation: Very fine particles in the water adhere together to form larger particles as the coagulant alum is mixed into the water. Large particles are effectively removed during the settling and filtering processes.
2) Settling: Settling is the process in which solid particles settle out and are removed from the water.
3) Fluoridation: Fluoride is added to improve dental health.
4) Filtration: The water is slowly filtered through 15” of granular carbon and 12” of crushed sand to remove very small particles.
5) UV Disinfection: After filtration, water passes through UV reactors where high intensity UV light inactivates pathogens such as Cryptosporidium and Giardia.
6) Chlorine Disinfection: After filters, chlorine is added as a secondary disinfectant. This provides extra protection from potentially harmful microorganisms.
7) Clearwell: Treated water is stored in deep underground tanks and pumped as needed through the distribution system.
8) Corrosion Control: A phosphorous compound is added to help control corrosion of pipes. This helps prevent lead and copper from leaching from plumbing into the water.
See the complete diagram