The removal of suspended matter from water is one of the major goals of water treatment. Only disinfection is used more often or considered more important. In fact, effective clarification is really necessary for completely reliable disinfection because microorganisms are shielded by particles in the water. Clarification usually involves: • coagulation • flocculation • settling • filtration This guide focuses on coagulation and flocculation: the two key steps which often determine finished water quality