Ozone for Well Water


ozone molecule

Ozone molecule

Water treatment methods can be classified as physical, like filtration, or chemical, like chlorination or ozonation. Often when we think of chemical water treatment, we naturally grow concerned about chemical residue. Well, that’s the fascinating thing about ozone – there is none. Why is that?

Ozone is a naturally occurring form of oxygen. The stuff we breathe is two oxygen atoms together (a.k.a. O2) while ozone is three oxygen atoms together (a.k.a. O3).  However, it is a highly reactive form and that third atom will disassociate and react with whatever it can. This makes ozone highly effective in treating well water, as it oxidizes nuisance contaminants like iron and manganese, causing them to form insoluble oxides that can be precipitated or filtered out. And in all these chemical reactions, the only by-products are oxygen, water, and carbon dioxide. Clean and simple. But perhaps the greatest benefit of ozone in water treatment is as a disinfectant.  Requiring very little contact time and using only small doses, ozone eliminates microorganisms by destroying the cell walls. In fact, ozone is generally regarded as superior to chlorine. So why isn’t everybody using it?

To begin with, as mentioned, ozone is highly reactive. So much so that it cannot be contained or transported and must therefore be produced on site and then bubbled into the water stream.  This requires either a corona discharge ozone generator or an ultraviolet light ozone generator – both requiring electricity. Historically, these have been industrial or commercial units, but more recently smaller versions appropriate for homes or cottages have been introduced to the market. A holding tank will be necessary as contact time is key to effective oxidation and disinfection. If the well water has excessive amounts of iron or sulfur, this may interfere with the disinfection process, as will high turbidity.  So pre-treatment may be required or greater amounts of ozone and contact time will be required for complete oxidation of these. And then, post-filtration will be needed to remove any oxides produced.  Periodically, this holding tank will also require cleaning. Lastly, any time an ozone generator is used, small amounts of ozone escape into the surrounding air. At ground level like this, ozone is quite dangerous and can cause respiratory issues.

Ozone for well water treatment can be very effective, providing the benefit of both oxidizing and disinfecting leaving no residual chemicals in the water.  You won’t be purchasing chemicals on an ongoing basis. But you will want to carefully weigh the maintenance and safety aspects of this approach to water treatment.  This is primarily what makes it less practical for home use.