THORNTON Leading Pure Water Analytics

Dissolved Ozone Measurement In Bottled Water

Application Note AN-0112

Background shelf life. For this, a dissolved ozone concen- tration measurement is made to assure an

Ozone (O3) is an unstable tri-atomic form of oxy- adequate level of sanitization has been gen. It is a very strongly oxidizing gas that is achieved. The ozone sanitizes and then dissi- injected into water to remove organics that may pates inside the bottle. The maximum ozone contribute color, odor or taste. Most importantly, level allowed in the product water by the US ozone sanitizes the water, rapidly destroying any FDA is 0.4 mg/L (ppm). microbiological contamination. Dissolved ozone reverts back to harmless oxygen in a matter of Higher levels of ozone can be injected minutes, depending on the temperature and pH of upstream but excessive amounts are discour- the water, so it must be generated and measured aged for several reasons. An excess of ozone right next to the process. Ozone leaves virtually requires venting and destruction to prevent no harmful breakdown products. escape to the atmosphere and resulting health hazards. Excess ozonation in mineral waters

Application Notes Ozone generators operate by passing dry air or that contain bromides will oxidize them to bro- oxygen next to high voltage electrodes where a mate which is a suspected carcinogen. corona discharge converts some of the oxygen to Bromate is limited to less than 10 μg/L (ppb) ozone much as occurs in a lightning storm. That by the US EPA for drinking water and by the gas mixture is then contacted with the water, FDA for bottled water. In addition, high ozone either in a tank diffusion system or in a pipe with levels can cause deterioration of some polymer venturi injector. Intimate contact is made to maxi- materials used in packaging. mize the dissolution. There are newer generation techniques that can produce ozone directly in the Dissolved Ozone Measurement water and reduce the possibility of atmospheric losses. For the reasons given above, on-line monitor- ing and control of ozonation have become Ozonation of Bottled Water standard practice. Dissolved ozone instrumen- tation is available ranging from sophisticated Bottled water is most commonly of two types: high cost, maintenance-intensive equipment mineral water which comes from a natural source giving good performance, to low cost, less reli- and is not altered significantly, and purified water able equipment with flow sensitive readings. which is treated with reverse osmosis and other For measurements with excellent performance, steps to adjust the mineral content. Both must be high reliability and infrequent simple mainte- sanitized with ultraviolet light or ozone. nance at reasonable cost, Mettler-Toledo Thornton offers dissolved ozone measurement Bottled water processing has embraced ozone as in a choice of two multiparameter instrument the best way to sanitize the system, the water, the platforms. bottle and its seal to achieve the longest possible © Subject toTechnical Changes Tech ServiceFax:+1-781-271-0675 Cust ServiceFax:+1-781-271-0214 Toll-Free: 1-800-642-4418 Phone: +1-781-301-8690 Customer/Technical Service [email protected] Toll-Free: 1-800-510-PURE Phone: +1-781-301-8600Fax:+1-781-301-8701 36 MiddlesexTurnpikeBedford,MA01730USA Mettler-Toledo Thornton,Inc. Mettler-Toledo Thornton, Inc. Application Notes measurement pointisrequired. most cost-effectivechoiceifonlyoneozone measure conductivity,pHorORP.Thisisthe dissolved ozoneandtheotherchannelcan measurements whereonechannelcanmonitor Thornton 2000Instrumentsprovidetwo-channel For bottledwaterapplications,Mettler-Toledo T From reatment 2000 Two-channelInstrument Vent Tank Storage Typical bottledwaterozonationsystem Sensor Ozone www.mt.com/thornton and/or measurementpointsarerequired. measurement needswherenumerousparameters unequaled flexibilityandvalueinsatisfying two additionalchannelsofflowrate.Itprovides dissolved oxygen,TOC,pressureandlevelplus dissolved ozone,conductivity,flowrate,pH,ORP, measure fromfoursensorsinanycombinationof Mettler-Toledo Thornton770MAXInstrumentscan 770MAX Six-channelInstrument Generator Ozone z Eductor Visit formoreinformation ofUse To Points