Which coagulant chemical is most widely used?

Alum, or aluminum sulfate, is the most widely used coagulant chemical in water treatment because of its effectiveness in removing turbidity and particulate matter from water. Its popularity can be attributed to several factors. First, alum works well in a variety of water conditions, helping to stabilize pH levels and effectively aggregating small particles into larger flocs that can be easily removed in subsequent treatment processes.

Additionally, alum is generally cost-effective and readily available, making it a practical choice for many water treatment facilities. The chemical can be easily dosed and has a long history of successful use, allowing operators to rely on established procedures and guidelines for its application.

Other coagulants like ferric sulfate and polyaluminum chloride are also effective, but they may not be as widely utilized or preferred due to factors such as higher cost or specific water chemistry considerations. Calcium carbonate serves a different purpose, primarily as a pH adjustment agent, rather than as a primary coagulant, which limits its use in coagulation processes.