Dissolved Ozone vs. Ozone Dosage
The amount of ozone applied to the water will always be greater than the amount of ozone absorbed into solution.
A portion of the ozone off-gases without being absorbed into the water due to system inefficiencies. This squandered ozone must then be vented or destroyed using an ozone destruct unit.
What are the Units of Ozone Dosage?
The units of measurement are also ppm or mg/l. But how can this be if the ozone hasn’t been dissolved into solution? Keep in mind that ppm is a ratio (1 ppm is one part ozone for every 1,000,000 parts molecules of water). The amount of ozone produced will be known to the operator. They will also be aware of the amount of water passing through a venturi (the typical method of injecting ozone). The ratio of generated gas to moving liquid yields a value that can be expressed in parts per million (ppm) (or mg/l).
An ozone system parameter can indicate an ozone dosage of 2.0 ppm. This is not to be confused with dissolved ozone. Due to losses, a dosage of 2.0 ppm ozone frequently results in dissolved ozone levels of 1.0 ppm or less.
You cannot expect the amount of ozone you add to the water to be constant. The water’s characteristics, such as the temperature, organic pathogens, etc., will diminish the dissolved ozone. You must keep adding ozone in order to overcome the pollutants and other ozone-depleting situations in order to reach the target dissolved ozone level.
The left picture represents ozone dosage which is the amount of ozone applied to the water. The right picture represents dissolved ozone which is the amount measured in the water.
Cited from ozonesolutions