Which chemical is typically used for floc formation in standard water treatment?

In standard water treatment, alum is commonly used for floc formation. Alum, or aluminum sulfate, serves as a coagulant that effectively helps to remove suspended particles, impurities, and microorganisms from water. When added to water, alum reacts to form positively charged aluminum ions, which attract the negatively charged particles and cause them to clump together, forming larger aggregates known as floc. This floc can then be easily removed from the water during subsequent settling or filtration processes.

Other chemicals mentioned, such as calcium sulfate, chlorine, and ozone, serve different purposes in water treatment. Calcium sulfate is typically not used for floc formation; it is more often involved in processes related to water hardness or as a calcium source. Chlorine is primarily used as a disinfectant to kill bacteria and other pathogens, while ozone is used for disinfection as well and has some oxidizing properties but is not a coagulant. Selecting alum for floc formation is thus critical in enhancing the efficiency of the water treatment process.