Ozone Systems
Disinfection is considered to be the primary mechanism for the inactivation/destruction of pathogenic organisms to prevent the spread of waterborne diseases to downstream users and the environment. It is important that wastewater be adequately treated prior to disinfection in order for any disinfectant to be effective. Table 1 lists some common microorganisms found in domestic wastewater and the diseases associated with them.
Ozone is produced when oxygen (O2 ) molecules are dissociated by an energy source into oxygen atoms and subsequently collide with an oxygen molecule to form an unstable gas, ozone (O3 ), which is used to disinfect wastewater. Most wastewater treatment plants generate ozone by imposing a high voltage alternating current (6 to 20 kilovolts) across a dielectric discharge gap that contains an oxygen-bearing gas. Ozone is generated onsite because it is unstable and decomposes to elemental oxygen in a short amount of time after generation.
What is ozone water treatment?
Ozone water treatment is a water treatment method that reduces contaminants through ozone’s oxidative strength. Ozone is an oxidant, which means it reacts with other substances and accepts their electrons. For example, when iron is oxidized, it becomes rust. Ozone water treatment begins with the creation of ozone in an ozone generator. Then, ozone is injected into water, and immediately starts oxidizing and eliminating contaminants, such as bacteria, viruses, and metals.
Ozone oxidizes organic material in the membranes of bacteria, viruses, and parasites. This weakens, ruptures, and kills their cells, eliminating the troublesome contaminants. Ozone also oxidizes iron, manganese, and copper into solid particles that can be easily filtered from water by mechanical filtration or certain activated carbon filters. Through oxidation, ozone water treatment systems can even rid water of turbidity and bad tastes and odors caused by chlorine.
How does ozone water treatment work?
Ozone water treatment works by dissolving ozone into water and through the ensuing oxidation of bacteria and other waterborne pathogens. To better understand the process, it is best to first understand how ozone is created. Ozone is born out of oxygen. An oxygen molecule contains two oxygen atoms (O2), while an ozone molecule contains three oxygen atoms (O3). When electricity or ultraviolet light stream through air, their energy splits oxygen molecules into two oxygen atoms. The loose oxygen atoms then recombine with ordinary oxygen molecules to form ozone. In the upper atmosphere, sunlight interacts with oxygen to produce earth’s protective ozone layer. While closer to the surface, ozone is created when lightning strikes and electricity cuts through oxygen rich air. Both processes are mimicked in ultraviolet and electrical ozone generators, which make ozone water treatment possible. Ozone can also be produced by electrolytic and chemical reactions, but UV and electrical ozone generators are the most common for water treatment.
