Characterization of Airborne Ozone Concentrations in a Bottled Water Manufacturing Facility
Open Access
- Author:
- Gazza, James
- Graduate Program:
- Energy and Mineral Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- April 02, 2013
- Committee Members:
- William Arthur Groves, Thesis Advisor/Co-Advisor
- Keywords:
- ozone
bottled water manufacturing facility
workplace
occupational exposure - Abstract:
- Ozone is a material that has several diverse associations. One of these is ozone’s presence high in the earth’s atmosphere that forms a barrier around the earth that protects human health, plant life and aquatic ecosystems from the harmful rays of the sun. Another is ozone’s infamous connection to smog and the detrimental impact smog has on public health. Still another is the use of ozone as a disinfecting agent against water-borne microorganisms in drinking water. It is this association that forms the basis for this research. Over the past several decades, the use of ozone has emerged in the bottled water manufacturing industry as the method of choice for disinfecting the bottle rinse water, product water, the bottle and the associated bottling equipment. It does this efficiently and effectively then quickly decomposes to oxygen without leaving an after taste or odor. However, while ozone is working as a disinfectant, it is also off-gassing from the ozonated rinse water and product water into the workplace atmosphere. It is at this point in the production of bottled water that the workers operating the bottle filling equipment may be exposed to ozone gas at potentially harmful airborne concentrations. This research paper summarizes the air sampling methodology that was employed to measure airborne ozone in an active bottled water manufacturing plant for the purpose of characterizing the airborne ozone concentrations. The statistical analysis performed for this research identified several variables that have the ability to influence the airborne ozone concentrations: 1) The level of ozone in the rinse water used to clean bottles prior to filling, 2) Production of ozonated water products versus spring water products, 3) Size of the bottles being filled, especially when filled with ozonated product water, and 4) The number of air handling units operating in the work area. Statistical analysis also revealed that there are specific production scenarios, including filling larger bottles with ozonated product, for which the mean airborne ozone concentration can temporarily exceed relevant occupational exposure limits such as the Occupational Safety and Health Administration (OSHA) 8-hour PEL-TWA of 0.1 ppm, the American Conference of Governmental Industrial Hygienists (ACGIH) 8-hour TLV-TWA (moderate work) of 0.05 ppm, and the OSHA 15-minute short term exposure limit (STEL) of 0.3 ppm. Although short-term concentrations for these scenarios ranged from 0.0516 - 0.1486 ppm, personal air sampling results for equipment operators in this work setting indicate concentrations were below the OSHA 12-hour adjusted TWA exposure limit of 0.067 ppm. Examination of the ozone concentrations measured at the two sampling points where operators spend most of their time, and for the time period over which three AHUs were operating, showed that data were distributed normally with a mean of 0.052 ppm and standard deviation of 0.020 ppm. Further, the distribution indicates that approximately 80% of the measured concentrations were below the OSHA 12-hour adjusted TWA exposure limit of 0.067 ppm. Understanding how production variables influence airborne ozone concentration and the measures such as room ventilation that can be taken to control exposures in the workplace atmosphere to below established exposure limits will help ensure a safe and healthy work environment for the operators of the bottle filling equipment. It is important to note that the results of this research are site-specific and may not be reflective of the bottled water industry (or other industries utilizing ozone as a disinfectant in their processes) in general. However, the knowledge and understanding gained from this research, with regard to how ozone behaves in an industrial setting, should be potentially useful to other bottled water manufacturing facilities or industries dependent on ozone in its processes when it comes to controlling this airborne contaminant.