Ozone Sterilization

An ozone sterilisation system generates ozone on-site from air or oxygen using a corona discharge generator, dissolves it into the water stream and applies a controlled dose to disinfect and oxidise contaminants. Ozone is one of the most powerful disinfectants and oxidising agents used in water treatment, effective against bacteria, viruses, protozoa, cysts and many organic micropollutants. After reacting with contaminants in the contact vessel, ozone decomposes back to oxygen, leaving no persistent chemical residuals in the treated water.

Ozone is a significantly stronger disinfectant than chlorine and achieves equivalent pathogen reduction at lower contact times and doses. Ozone is more effective against chlorine-resistant pathogens such as Cryptosporidium and Giardia cysts and does not form trihalomethanes or haloacetic acids, which are regulated disinfection byproducts associated with chlorination of water containing natural organic matter. Unlike chlorine, ozone leaves no residual disinfectant in the distribution system, so a secondary disinfectant such as chlorine or chloramine is typically added downstream for residual protection.

IWTE ozone systems use corona discharge generators, which pass dry air or pure oxygen through a high-voltage electrical discharge gap. The electrical energy breaks apart oxygen molecules, allowing ozone molecules to form. Oxygen-fed generators produce significantly higher ozone concentrations (6 to 12 percent by weight) compared to air-fed units (1 to 3 percent by weight), achieving higher dissolved ozone doses at lower gas flow rates. The choice between air-fed and oxygen-fed generation depends on the required ozone dose, site space and the availability and cost of oxygen supply.

CT value is the product of the disinfectant residual concentration (C, in mg/L) and the contact time (T, in minutes), and is the standard measure used to quantify disinfection efficacy for a given pathogen and log reduction target. Regulatory bodies specify minimum CT values for different pathogens and treatment scenarios. IWTE designs ozone contactor vessels and operating parameters to achieve the CT value required by the applicable drinking water standard or site permit, with contact time and ozone residual confirmed through commissioning testing and ongoing operational monitoring.

Advanced oxidation process (AOP) combines ozone with hydrogen peroxide or UV irradiation to generate hydroxyl radicals, which are far more reactive than ozone alone and capable of destroying refractory organic micropollutants including pharmaceuticals, pesticides, endocrine-disrupting compounds and taste and odour compounds that resist conventional ozone treatment. IWTE designs ozone AOP systems for drinking water applications where micropollutant removal is required, integrating ozone generation and dosing with hydrogen peroxide dosing or UV reactor stages within a unified automated system.

Ozone is a reactive gas that requires appropriate engineering controls and safety measures in water treatment applications. IWTE incorporates off-gas destruction units in every system to decompose undissolved ozone from contactor vessel headspaces before venting, eliminating occupational exposure. Ambient ozone monitoring with audible and visual alarms, automatic generator shutdown on high ozone detection, confined space ventilation requirements and operator safety protocols are all addressed within the system design and commissioning documentation. All IWTE ozone systems are designed and supplied in compliance with applicable safety standards.

Yes. Ozone is highly effective at oxidising and destroying the geosmin and 2-methylisoborneol (MIB) compounds responsible for earthy and musty tastes and odours in drinking water, as well as hydrogen sulphide, phenolic compounds and other odour-causing substances. Low ozone doses of 0.5 to 2 mg/L are typically sufficient for taste and odour control, making ozone one of the most cost-effective treatments for this common water quality problem. Ozone is particularly beneficial for water utilities dealing with seasonal taste and odour events driven by algal activity in source water reservoirs.

Yes. IWTE designs and supplies ozone sterilisation systems as standalone units and as integrated disinfection stages within complete water treatment plants. The ozone system is engineered to match the plant flow rate, water quality and disinfection objectives, with unified PLC and SCADA control across the full treatment train. IWTE also provides commissioning, operator training, CT value validation support and ongoing service contracts for all ozone systems we supply.