Dissolved Ozone Measurement in Bottled Water

Bottled water is most commonly of two types: mineral water which comes from a natural source and is not altered significantly, and purified water which is treated with reverse osmosis and other steps to adjust the mineral content. Both must be sanitized with ultraviolet light or ozone. Bottled water processing has embraced ozone as the best way to sanitize the system, the water, the bottle and its seal to achieve the longest possible shelf life. For this, a dissolved ozone concentration measurement is made to assure an adequate level of sanitization has been achieved. The ozone sanitizes and then dissipates inside the bottle. The maximum ozone level allowed in the product water by the US FDA is 0.4 mg/L (ppm). Higher levels of ozone can be injected upstream but excessive amounts are discouraged for several reasons. An excess of ozone requires venting and destruction to prevent escape to the atmosphere and resulting health hazards. Excess ozonation in mineral waters that contain bromides will oxidize them to bromate which is a suspected carcinogen.