What is an example of a coagulant aid?

Activated silica is recognized as a coagulant aid because it enhances the coagulation process by promoting the agglomeration of particles in water treatment. Coagulant aids help improve the performance of primary coagulants by providing additional surface area and enhancing the settling characteristics of floc formed during the coagulation process.

In practical applications, activated silica works by adsorbing onto fine particles, thus increasing their size and encouraging them to bind together more effectively. This leads to the formation of larger, more easily removed flocs during subsequent sedimentation and filtration processes, thereby improving overall water quality.

Other options mentioned, such as calcium hypochlorite, are primarily disinfectants rather than coagulants or coagulant aids. Polyaluminum chloride serves as a primary coagulant rather than a coagulant aid. Sodium bicarbonate is often used for pH adjustment but does not function as a coagulant or aid in coagulation processes.