Which substance is commonly used as a coagulant in water treatment?

Aluminum sulfate is widely recognized as a coagulant in water treatment processes. Coagulation is a critical step in water purification, where coagulants help to aggregate and settle out suspended particles and impurities that may be present in the water.

When aluminum sulfate is added to water, it reacts with the natural alkalinity present in the water to form aluminum hydroxide, which is a gelatinous substance. This aluminum hydroxide precipitate traps small particles, bacteria, and other contaminants present in the water, allowing them to be removed more easily during subsequent filtration stages.

The use of aluminum sulfate is particularly effective because it can work efficiently across various pH conditions and is effective in a wide range of water qualities, making it a go-to choice for municipal water treatment facilities. The resulting flocs that form during this process help clarify the water by making it easier to filter out debris and impurities.

Other substances such as calcium sulfate, potassium chloride, and sodium phosphate are not primarily used for coagulation in water treatment. Calcium sulfate is more commonly associated with hard water issues and doesn’t function as a coagulant. Potassium chloride typically serves as a source of potassium ions and is often used in water softening processes rather than coagulation. Sodium phosphate can