Ozone (O₃) is a triatomic form of oxygen. It forms naturally when UV light or electrical discharge splits O₂, and the single oxygen atom binds to O₂ to make O₃. In industry, ozone is commonly produced on-site using an ozone generator, with corona discharge and electrolysis being two of the main production methods.

Ozone is a powerful oxidant that attacks cell walls, viral capsids and nucleic acids, rapidly inactivating bacteria, viruses and protozoa. It leaves no persistent chemical residue because it decays to oxygen after reaction.

Typical uses include primary disinfection, colour/odour removal, oxidation of iron/manganese, micropollutants, and advanced oxidation with H₂O₂ or UV. It is widely used in drinking water and tertiary wastewater disinfection.

CT is the product of disinfectant concentration (C, mg/L) and contact time (T, min). Higher CT improves inactivation. In practice, concentration and contact time must be considered together rather than treating ozone dose as a standalone figure.

The half-life of dissolved ozone depends on temperature and water chemistry. At neutral pH it is typically around 20 minutes at 20 °C and around 15 minutes at 25 °C, with shorter persistence at higher temperature, higher alkalinity or higher organic loading.

Ozone can be used in certain food and hygiene-related applications where the system is correctly engineered, controlled and compliant with the relevant site procedures and regulations. It is valued because it decomposes back to oxygen and does not leave a persistent chemical residual.

No. Ozone should not be used as a routine air purifier in occupied spaces. It is a powerful oxidising gas and can present respiratory risks if people are exposed to elevated concentrations. Air and odour applications should be treated as engineered systems with suitable monitoring, controls and residual ozone management.

Ozone exposure limits vary by jurisdiction and standard, but industrial systems should always be designed to prevent unsafe occupational exposure. Suitable engineering controls, ventilation, ozone monitors, alarms and interlocks are normally required where ozone is generated or applied.

Breathing ozone can irritate the respiratory system. Short-term exposure may cause coughing, throat irritation, chest discomfort or reduced lung function, and it can aggravate existing respiratory conditions. This is why ozone systems must be designed with containment, monitoring and safety controls.

Commonly suitable materials include 316L stainless steel, titanium, PTFE, PVDF, FKM/Viton, glass and ceramic. Some elastomers and plastics may degrade depending on ozone concentration, moisture, temperature and exposure time. Material compatibility should always be checked for the specific process conditions.

Start by defining the treatment goal, flow rate, water or air quality, target contaminants, required contact time and monitoring method. From there, the system can be sized around the actual application rather than just the nominal ozone output.

In water, residual ozone is commonly monitored with dissolved ozone sensors, while ORP may be used as a process indicator in some applications. In gas-phase systems, ambient ozone monitors, off-gas sensors and interlocks are often used for safety and control. Generator output may be adjusted manually or automatically depending on the system design.

Ozone is treated as an active substance under biocidal regulations where biocidal claims are made. Requirements can depend on the product type, claim, market and application. Businesses should review the relevant UK or EU regulatory position before marketing ozone systems for specific disinfection claims.

Ozone is generated on-site from air or oxygen and decomposes back into oxygen after reaction. This can reduce the need for stored chemicals in some applications. However, environmental performance still depends on correct system design, energy use, off-gas destruction and whether ozone is genuinely suitable for the treatment objective.