Chlorine and other chemical disinfectants have been popular for their price/performance ratio. However, ozone has proven to be a highly effective and useful alternative. On its own, ozone is a potent yet environmentally friendly disinfectant agent that outshines other choices. When using treatments that combine ozone’s immediate effects with long-term disinfectants, the results and savings can be significant.
“Ozone doesn’t last long, and it leaves no chemical residual,” says Brendan van Wyk, business development manager at Xylem. “If we were to disinfect a room with ozone, during the procedure it would be hazardous to be in that environment. But after about 20 minutes, it would be perfectly safe to re-enter the room, with little or no trace of any ozone being detected. This is because ozone (O3) is very unstable and reverts back to oxygen (O2).”
This view is backed by research, such as trials undertaken in 2014 by Campden BRI. It found that ‘ozone at appropriate concentrations and contact times has the potential to be an effective environmental disinfectant.’ The trial also established that, when used correctly, ozone caused no adverse contact effects afterwards.
A powerful disinfectant
Ozone is brutal on organic material. Highly unstable, ozone attracts electrons from other compounds, oxidizing them and drastically reducing their integrity. In the case of biological targets such as bacteria, ozone attacks their cellular walls, causing the cells to rupture and ensuring there is no chance for the organism to build up an immunity to it, unlike other disinfectants. Ozone is very effective at oxidizing certain minerals as well. It’s used to remove manganese and iron out of drinking water, as an example.
If you want to disinfect a room thoroughly, flushing the room with ozone gas may do the trick. Modern HVAC systems often use ozone to purify air passing through the system to prevent mould and smell. Ozone manufacture can be done quite easily and reliably, within a small footprint.
With no moving parts and few maintenance requirements, the system can be operated remotely with no human intervention. Ozone only needs power and air for manufacture, and the units can be custom designed to suit the specific project specifications. Brendan explains, “Ozonated water is already used in places like abattoirs as wash water. This allows for maximum disinfection, but without a chemical residue that needs to be treated. It is easy to retrofit an ozone dosage system into an existing wash line. Clean technologies for rinsing and disinfection of milk bottles and soft drink bottles are already widely used.”
Safe and easy to use
Other examples of uses include cleaning animal enclosures and aquariums, rehabilitating smoke-damaged rooms, washing taxi ranks, and disinfecting laundry. Ozone-enriched water is mighty as a disinfectant without leaving a chemical residual (as chlorine does) that could run into natural water systems through storm water channels and disrupt natural biological action.
As mentioned earlier, ozone gas breaks down quickly, rendered into harmless oxygen that can enrich the local atmosphere and improve the chemical oxygen demand (COD) of wastewater.
A specific application where ozone would also be very effective in disinfecting schools after the learners and teachers have gone home. Automated systems can flood the classrooms with ozone which would be more effective on non-uniform surfaces such as carpets, books and stationery that cannot necessarily be wiped down or covered. The ozone would then decompose fully before the return of the children and teachers, leaving a disinfected room.
Ozone needs little to no handling. A modern ozone generator can operate without intervention and doesn’t require any chemical additives. This negates the need to stockpile chemicals, not to mention the risks of handling dangerous materials. Ozone is also very cost-effective: its capital investment is soon recovered through water and chemical savings, as well as a reduction in effluent treatment costs. Recoupment of capital costs can take as little as two years on industrial systems like cooling tower water treatment.
Brendan explains, “To give an example of how the costs work, let’s apply ozone to a water treatment plant. Normally, you’d apply large volumes of chlorine in the final stages of the treatment process. Much of this is first to disinfect the water, and the rest is to keep a residual for long term disinfection. If we added an ozone generator to the treatment process, the water is disinfected without the use of chlorine, then a much smaller amount of chlorine is added at the end of the process to keep the water clean.
“Ozone does the heavy lifting of primary disinfection, without the generation of chlorinated byproducts, while improving the taste and odour. It is much safer, and it requires smaller amounts of chemicals, so the costs of purchasing, storing and handling chemicals are reduced.”
Ozone technology offers different types of generators, from covering treatment plants to turning home pool water clean and bright. It is modular, environmentally friendly and a highly effective treatment product without the need for ongoing purchasing of chemicals and a workforce required for handling make-up and dosage requirements. The systems are self-contained and operate without human intervention.
“If you are concerned about chlorine’s chemical footprint, or you want to handle disinfection in a much more efficient and effective manner, ozone is the answer. It’s Mother Nature’s own disinfectant: ruthlessly efficient but without leaving a calling card. Whether used to augment or replace other disinfection systems, ozone is a potent ally against infectious agents, a superior long-term disinfection and treatment investment that is friendly to the environment,” Brendan concludes.
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