One of the primary categories of chemicals used in wastewater treatment is coagulants. Coagulants are substances that help remove suspended solids from wastewater by neutralizing the charge on these particles, allowing them to aggregate and settle out more easily. Common coagulants include aluminum sulfate (alum), ferric chloride, and polyaluminum chloride. These chemicals facilitate the process known as coagulation-flocculation, where small particles combine to form larger aggregates, or flocs, that can be removed from the water.
