Which compound is commonly used as a typical coagulant in water treatment?

Aluminum sulfate, commonly referred to as alum, is widely used as a coagulant in water treatment processes. When added to water, aluminum sulfate reacts with dissolved impurities and forms flocs, which are larger particles that can be more easily removed from the water. This coagulation process is essential for improving water clarity and quality, as it helps to eliminate suspended solids, organisms, and colloidal matter.

The effectiveness of aluminum sulfate in water treatment stems from its ability to lower the charge of suspended particles, facilitating their aggregation into larger clumps. When these clumps form, they can be removed through sedimentation or filtration processes, leading to cleaner water. Furthermore, aluminum sulfate has been utilized in water treatment for many years, making it a well-understood and reliable option in the field.

In contrast, sodium chloride is primarily used for water softening, calcium carbonate is often used to control pH and alkalinity, and potassium nitrate is utilized mainly as a fertilizer, rather than as a coagulant in water treatment processes.