Which of the following are common coagulants used in water treatment?

In water treatment, coagulants play a crucial role in improving water quality by removing suspended solids and facilitating the aggregation of smaller particles into larger flocs that can be easily removed. Common coagulants include alum, ferric sulfate, and ferrous sulfate.

Alum (aluminum sulfate) is one of the most widely used coagulants due to its effectiveness in neutralizing the charges on particles and promoting floc formation. Ferric sulfate is another effective coagulant, providing both coagulation and additional benefits, such as aiding in disinfection and removing color from water. Ferrous sulfate can also serve a similar purpose, assisting in the removal of contaminants through coagulation processes. The selection of specific coagulants depends on the water quality and treatment goals, but alum and the iron-based coagulants are prominent in conventional treatment processes.

The other options do not represent common coagulants. Calcium carbonate and magnesium sulfate are primarily used for different water treatment processes, such as pH adjustment or hardness control rather than coagulation. Sodium chloride is typically utilized for water softening and not as a coagulant. Chlorine and ozone are strong disinfectants used for sterilization rather than for coagulation. Thus, the presence of alum, ferr