It has been over 170 years since the d iscovery of the ozone (O3) molecule. Since that time, scientists and engineers have been testing and evaluating ways to use ozone in many different processes, from water and air treatment to surface and food sanitation. The evolution was somewhat slow in the early days, taking nearly 50 years before Europeans found, in 1886, that ozone could be used for water disinfection. From that point, it continued to pique the interest of those in pursuit of developing safe water treatment practices. Another well-known application, however, has brought ozone to the forefront; the treatment of swimming pool and spa water. The US saw its first use of ozone in a commercial pool in 1937, and has continued to use ozone for its oxidative qualities since. In more recent years, ozone has been the oxidizer of choice, and mandated for use of all Olympic training and competition swimming pools, for its disinfection and oxidation capabilities. Over the last century, ozone generation equipment has evolved and is now available on a small scale for residential use. Water treatment professionals may already know of ozone's potential, and may be using it as another tool in their bag for these small-scale residential water treatment applications. With better knowledge and understanding of ozone and the residential pool and spa application, they may also be able to use this same tool to obtain more business from their current customer database.
Oxidation strength of ozone
Oxidizers react with organic and inorganic compounds by donating or receiving electrons and can improve water quality by sanitizing and precipitating (causing suspended contaminants to drop out of the water as solids). The most recognized commercially available oxidizers include chlorine (gas and liquid), hydrogen peroxide and bromine; however, ozone still remains the most powerful oxidizer commercially or, in this case, residentially.
Benefits of ozone
Because of ozone's high oxidation potential, it can change the molecular structure of organic and inorganic compounds, allowing them to be precipitated from pool water. Once these compounds are precipitated, ozone also helps to flocculate (or bind) the precipitated solids together, allowing them to be easily removed from the water via the pool filtration system. These compounds can include lotions, body oils, sweat and saliva among others. Ozone is also most effective in killing bacteria, cysts and viruses up to 3,125 times faster than chlorine, which is one reason it is used for the disinfection and purification of municipal and residential water treatment supplies worldwide. Ozone can also be very effective in killing algae spores that travel through the ozone contact system. Due to its short half-life, however, it is recommended that a small residual of chlorine (often 0.2 to 0.5 ppm) or an algaecide (such as a phosphate remover) be used in residential pool or spa waters to prevent algae blooms, in addition to scheduled brushing of the pool walls and standard pool maintenance. A key benefit to the use of ozone in swimming pools and spas is not only its ability to oxidize, but also to destroy bacteria and viruses completely—unlike chlorine—with the only byproduct being oxygen. Chlorine often does not have enough contact time to completely oxidize these contaminants, causing chlorine oxidation byproducts called trihalomethanes (THMs). THMs, some of which are carcinogens, are often measured in pool water as combined chlorine, and are the cause of the chlorine smell, faded swimwear, burning eyes and green hair. Ozone, on the other hand, will not only destroy the contaminants completely, but can also oxidize the byproducts of chlorine disinfection, all from a product that can be easily and safely generated onsite.