In which stage of water treatment is coagulation primarily utilized?

Coagulation is primarily utilized in the pre-treatment stage of the water treatment process. This stage involves the addition of chemicals, commonly known as coagulants, to water to facilitate the aggregation of small particles and impurities into larger particles, or flocs. The main goal of coagulation is to remove suspended solids, bacteria, and organic matter from the water before it undergoes further treatment processes like sedimentation and filtration.

During the coagulation process, when coagulants such as aluminum sulfate or ferric chloride are mixed with water, they neutralize the charges on particles, allowing them to clump together. This is essential because uncoagulated particles tend to remain suspended due to their negative charges repelling one another. By facilitating the formation of flocs, coagulation enhances the efficiency of subsequent treatment stages, ensuring that water quality improves significantly as contaminants are removed.

Understanding this role of coagulation helps highlight its importance in pre-treatment, setting the stage for effective contaminant removal and ensuring safe drinking water.