Aluminum sulfate, often recognized by its historical name alum, is an indispensable chemical in the vital field of water treatment. Its primary function revolves around its remarkable ability to act as a flocculant. When introduced into water sources, aluminum sulfate causes microscopic impurities, such as suspended solids, organic matter, and colloidal particles, to clump together. These larger, heavier aggregates, known as flocs, then settle out of the water more readily. This process is crucial for municipal water suppliers and industrial facilities alike, as it effectively removes turbidity, color, and various contaminants, making water safe for consumption and use.

The efficacy of aluminum sulfate as a coagulant is well-documented. Its chemical properties allow it to neutralize the negative charges on suspended particles, facilitating their agglomeration. This makes it a cost-effective and efficient solution for treating both drinking water and wastewater. For instance, in swimming pools, it helps maintain water clarity by settling out fine particles that cause cloudiness. The ongoing research into optimizing its application, such as in the treatment of papermaking white water, further highlights its adaptability and importance in managing water resources efficiently. Understanding the optimal dosage and conditions for aluminum sulfate application is key to maximizing its benefits in water purification, a process that underpins public health and industrial operations.