By Kevin Osborn

While municipal water systems are treated and monitored for contaminants, owners of private household wells do not have the same benefits. Private wells are not monitored, so it’s up to the homeowner to treat their water. Contaminants like iron, manganese, sulfur, and harmless bacteria (i.e., iron and sulfur-reducing bacteria) commonly found in well water can affect its clarity, taste, and smell. It is up to homeowners, working with a water treatment professional, to develop a solution that clears the way for better water to use throughout a home.

Air induction backwashing filtration products are a go-to solution for many water problems. And for good reason—air can easily oxidize the contaminants to help the filtration media remove contaminants from the water. However, in areas of the country where nuisance iron, bacterial iron, iron algae, and sulfur-reducing bacteria are present, it is best to start treating the water with a point-of-entry, or whole-house, filtration system that includes an ozone generator.

Here is one reason why: If, for example, you install a catalytic carbon system unaware that these harmless bacteria exist in the water, that bacteria can load up inside the tank. Once the tank is loaded with these nuisance bacteria, this environment is a great place for that bacteria to live and even grow into a larger problem. The more bacteria that exist inside the filter, the harder it is to clean and remove. The only way to kill these nuisance bacteria is with some form of oxidant such as chlorine, hydrogen peroxide, or ozone. Applying ozone at this point will not take care of what has built up in the tank and may result in the need to re-bed the filter. In these situations, installing an ozone generator first is a better strategy to prevent the initial growth and build-up of bacteria.

What Is Ozone?
Ozone is electrified oxygen. When oxygen molecules (O₂) are electrified, they break apart and get supercharged; they then reform into three oxygen molecules turning into ozone or O₃. Ozone occurs naturally and easily; for example, when lightning strikes during a storm, it electrifies the air causing the oxygen around us to become supercharged and forming O₃. That effer­vescence you smell in the air after a thunderstorm is naturally occurring ozone.

More often than not, it acts as a powerful natural disinfectant, helping to combat bacteria and other contaminants. That is what makes it especially beneficial in treating well water.

How Ozone Helps Combat Contaminants
When an ozone generator is installed on an air induction filter at the entry point of water, it draws air through a cylinder during every regeneration process, commonly during regeneration brine draw. The air is then electrified, transforming into ozone. In that way, manufacturers of ozone generators essentially found a way to simulate lightning, put it in a box, and utilize the ozone it creates to help the air induction oxidize the contaminants in water so the catalytic media used can filter the water. The ozone is drawn into the water system’s filter tank where it begins to do its part in helping rid the water of iron, manganese, sulfur, and best of all, those nuisance bacteria. It acts a lot like chlorine or hydrogen peroxide does when used to target and prevent bacteria growth.

What Type of Products Use Ozone?
Consider the presence of iron in well water. Iron has three forms: ferrous, ferric, and iron bacteria. Ferrous iron is completely dissolved to the point of being invisible, so water appears clear. Ferric iron is in suspension due to oxygen exposure, which some refer to it as icky and sticky. It can be seen as a solid particle and filtered out of water. Iron bacteria, which is harmless to human health, feeds on ferrous iron and converts it to a slimy ferric iron. Ferric iron is fairly easy to capture with filtration media, but that is not true of ferrous iron. We need to convert it to something that can be captured by the filter. Ferrous iron becomes a particulate when oxidized by air. During regeneration, the filter will pull in air to create a chamber that exposes the dissolved contaminants to oxygen. This process oxidizes ferrous iron into a tangible particle that can be captured by the media below. The amount of iron in the water has not changed, it has just changed form.

Air-injected point-of-entry filters have similar effects on sulfur and manganese. Hydrogen sulfide, for example, resides in water as a gas and causes a rotten egg smell. Although the gas cannot be filtered, the top air chamber allows the gas to come out of the water. The catalytic carbon then converts any gas that does not come out of the water to elemental sulfur, which can then be filtered. The process is the same for manganese dissolved in water. The element, related to iron and usually found with iron in water, gets oxidized and filtered the same way.

In the old way of doing things, oxidants like chlorine or hydrogen peroxide were injected directly into the water supply so that these elements could be oxidized and then filtered. However, this practice required more maintenance on the part of the homeowner. Instead, the water treatment industry minimized those applications and considered how to draw air into the system to create that oxidation process inside the system. One of the old ways of drawing in air used a micronizer, which is a nozzle with a check valve installed on the inlet of a plumbing system. When the micronizer is opened, it would suck air into a pipe. This method, however, caused problems when iron would build up and become sticky, causing the check valve to stay open or closed. It was not a good way to create better filtration.

Manufacturers made a better mousetrap, so to speak, by taking the principle of a softener and modifying it for filtration. Essentially, they cut the brine line so now instead of drawing brine, air is drawn. Although the air induction systems worked great for iron, manganese, and sulfur, the systems still needed help treating nuisance bacteria, and ensuring that air (ambient air contains 21% oxygen) was enough to help filtration media have enough oxygen to do their job. This then took us to the technology we have today.

Why not make things even better and add some electrified air to create ozone? Whether you are using an air induction sys­tem to filter iron, manganese, sulfur or, in some cases, convert Arsenic III to Arsenic V, ozone helps the filter media and air convert the contaminants to be more easily captured. Ozone is a great way to start the water treatment process because it keeps the filter media clean and working properly and will help control bacteria that can cause slime buildup in the tank and control valve. Ozone does not stay in the air head—it dis­sipates, which gives ozonation an advantage in reducing build-up in the system due to biofilm and other slime bacteria.

Now one thing to note, the ozone that is generated with these backwashing air filtration systems has a short shelf life. The ozone that is drawn during the regeneration process dissipates quite quickly due to the overall oxygen demand and organics in the water and therefore can not be used for harmful bacteria.

Benefits of Ozone in Water Treatment
The use of ozone offers several benefits. Ozone systems need minimal amounts of maintenance. Homeowners also do not need to worry about using chemicals or other additives to help the system work.

Because ozone occurs naturally, it is environmentally friendly. While too much ozone can be corrosive, the amount generated in this water treatment process is safe. The minimal amount that these generators create will not cause corrosion or harm the water system.

More Water Concerns May Require More Maintenance
There are times, of course, when an ozone generator needs to be serviced. The frequency of needing service depends upon the quality of the water. In extreme cases with problem water, servicing occurs about once a year. The type of service will depend upon the manufacturer. Additionally, in some units, ozone that runs very frequently or if it’s installed in high-moisture areas, may form build-up on the ozone cell and would need to be cleaned to continue operating as intended. In those cases, make sure the tube is completely dried after cleaning because it will cause problems by shorting out the generation of ozone. Although you can clean these tubes due to the low dose of ozone and the fact they are not really designed for service, if they fail, then simply replace them.

A Buyer Beware Note About Filtration Media
Finally, because ozone is a very strong oxidizer, you must be mindful of the filtration media used with these systems. Some media, like birm and other medium that use manganese dioxide catalyst, cannot tolerate ozone. And media that cannot tolerate the other oxidants—chlorine and hydrogen peroxide—will not tolerate ozone, so avoid their use with an ozone generator feature. Activated carbon and manganese dioxide are two of the most common filtration media used with ozone.

To treat well water effectively takes applying the right product to the water’s problem. What is in the tank, including the chemical makeup of the water, as well as the media used to filter it, is more important than the ozone itself, should you be considering its use. There is no doubt that if the contaminants found in the water call for ozone treatment, it is a simple, safe, environmentally friendly solution that is highly effective and essentially maintenance free for homeowners.

About the author
Kevin Osborn has been the Northeast Regional Sales Manager for Water-Right for the past nine years. He has been in­volved in sales and engineering in the drinking and wastewater industry for over 20 years and has a BA in Mechanical Engineering from WPI in Worcester, MA. Osborn’s primary role involves managing and supporting A. O. Smith’s water treatment brands through collaboration with distributors and professional water treatment dealers.

Water-Right is a manufacturer of residential and commercial water treatment products established in 1963. They offer a variety of brands with patented features distributed through wholesale and dealer-direct channels. Water-Right was acquired by A. O. Smith in the spring of 2019 to join their Water Treatment division.

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