Which process is NOT commonly used for water sterilisation?

Reverse osmosis is a process primarily used for the removal of dissolved solids and impurities from water, making it an effective method for purifying water rather than for sterilization. It works by pushing water through a semi-permeable membrane that allows water molecules to pass while blocking larger particles, impurities, and most contaminants.

In contrast, methods that are commonly used for sterilization, such as chlorination, ozonation, and ultrafiltration, have specific mechanisms aimed at eliminating microorganisms and pathogens. Chlorination involves adding chlorine to water to kill bacteria and viruses. Ozonation uses ozone gas, which is a potent disinfectant, to destroy pathogens in water. Ultrafiltration utilizes membranes to physically remove bacteria and viruses based on their size, providing a barrier to these contaminants.

Therefore, while reverse osmosis is a crucial process in water treatment, it is not primarily aimed at sterilization, which positions it as the method that is not commonly associated with water sterilization efforts.