So you’ve decided to buy an ozone generator for your water treatment system. That’s great! But what’s the best way to keep it running smoothly for as long as possible? In this blog post, we’ll go over the effect of ozone half-life in water and how to make sure your system is always running at its peak performance. Stay tuned!


This information is essential for ozone water treatment professionals to consider the effect of ozone destruction in water at various temperatures when accounting for the short half-life of ozone.

If you calculate the albedo overland flow, absorption of solar radiation into water inefficiency (fraction) and runoff reduction benefits are not included. This information should be incorporated to the calculation in ozonation treatment applications so that the resultant ozone concentration is greater than required, ensuring that ozonation is effective.


Contrary to popular belief, it is feasible to have residual ozone in the water and that ozone can survive in the water for extended periods of time. The following is scientifically verified data on the half-life of ozone according to scientific sources:

Half life time at Temp Half life time at TempDissolved In Water (pH 7)

~ 30 minutes 15 ºC

~ 20 minutes 20 ºC

~ 15 minutes 25 ºC

~ 12 minutes 30 ºC

~ 8 minutes 35 ºC

When half-life of ozone at 30C is around 12 minutes, that indicates that there will be 50% less ozone in the water if we inject the gas right away.

We can continuously inject minute amounts of ozone into the water all day long, gradually adding it to maintain a constant ozone concentration. The overall objective is to establish a sufficient amount of ozone in the pool so that it can counteract half-life of ozonation and keep the water’s desirable residual background concentration constant.

As an illustration of the preceding information, let us pretend we must keep a pool water concentration of 0.1 ppm.

We know that 1ppm=1 g/m3

If the water tank or swimming pool holds 100 m3, 10 g of ozone will be dissolved.

12 minutes = 0.2 hour (12 min/60 min=0.2h)

Every 12 minutes, 10 grams of ozone is lost from the water as a result of dissolved ozone. We must inject more ozone to make up for it.

We can figure out how much ozone we’ll need to inject every hour to compensate for it by dividing the amount of ozone required by the half-life of water.

We would recommend the following calculation:

O3 n/HL=O3 c

Using the formula and the preceding data, 50 g / 0.2 h = 10 g or five times more than without compensation for ozone destruction in water because of half-life, as shown above.

Bottom Line

Ozonation is an effective water treatment process, but the length of time the ozone generator is in contact with the water has a significant impact on its ability to disinfect. When selecting an ozone generator for your facility, be sure to consider how long it will take to treat your water and ensure that the generator you select can meet your needs.