Sterilization and Disinfection During Water Treatment

Sterilization and Disinfection: Water disinfection methods can be divided into chemical and physical methods. Physical disinfection methods include heating, ultraviolet (UV) light, and ultrasound; chemical methods include chlorination, ozone, heavy metal ion treatment, and other oxidizing agents. Here, we will only briefly introduce the UV (ultraviolet) method (physical disinfection) and the ozone (O3) method (chemical disinfection):

Ultraviolet Light: When a mercury lamp is lit, it emits ultraviolet light with a wavelength of 1400-4900 nm (1 nm = 10⁻¹⁰ m). This light can penetrate the cell walls of bacteria, killing microorganisms and achieving disinfection. The effect is best at a wavelength of around 2600 nm. UV disinfection is mainly used for small-volume drinking water treatment. Its characteristics are: strong bactericidal ability, short contact time; simple equipment, convenient operation and management; the treated water is colorless, odorless, and poses no risk of poisoning; it does not increase chlorine ions like oxygen does. However, UV light does not have the sustained bactericidal effect of residual chlorine, and mercury lamps have a short lifespan, are expensive, and have a small treatment capacity. Ozone is a blue gas with a distinctive fishy odor at room temperature, its molecular formula being O3. Ozone is an allotrope of oxygen; it decomposes into single oxygen atoms at room temperature, and each single oxygen atom possesses extremely strong oxidizing properties. Ozone can oxidize and denature the proteins of bacteria and fungi, neutralize electrolytes, kill vegetative bacteria and spores, viruses, and fungi, and destroy botulinum toxin. It can remove and kill toxic substances and bacteria in the air, water, and food, and eliminate odors. It is widely used in the disinfection and sterilization processes of food production. During disinfection and sterilization, ozone only produces non-toxic oxides; excess ozone is eventually reduced back to oxygen, leaving no residue on the disinfected items. It can be directly used for the disinfection and sterilization of food.