Consumption of bottled water has been on the rise over the last several years. In 2020, Americans consumed 15 billion gallons of bottled water, which was up 4.2 percent from 2019. In 2019, Americans consumed 14.4 billion gallons of bottled water, which was up 3.6 percent from 2018.
Bottled water’s retail dollar sales has also grown over the years; in 2020, sales were up 4.7 percent reaching $36.3 billion and in 2019, sales were up 5.2 percent reaching $34.6 billion. Per capita consumption has risen over the years as well; in 2019, per capita consumption rose 3.1 percent to 43.7 gallons and in 2020, per capita consumption rose 3.5 percent to 45.2 gallons.
Bottled water is the number one packaged beverage product in the U.S. and the industry employs nearly a quarter of a million people. Moreover, it is a global product, so the size and scope of the global industry is much larger than the U.S. industry.
Ozone Use in the Bottled Water Industry
Ozone is used extensively in the bottled water industry and enables water bottlers to produce high-purity, shelf-stable water free of unwanted chemicals. Additionally, ozone removed the taste and odor associated with the use of chlorine for water treatment. These features of taste, odor-free, healthy water helped the growth of the bottled water industry. Ozone proved to be a versatile disinfectant that could treat the water, bottling equipment, bottle, and cap, and then decomposes to oxygen without leaving a taste or odor.
In the United States, bottled water is officially regulated by the FDA, but most countries have regulations regarding the various types of bottled water. Since the author’s experience is limited to the U.S., this article will discuss the U.S. industry practices.
The major trade group is the International Bottled Water Association (IBWA). IBWA views itself as the authoritative source of information about all types of bottled water. IBWA also views its role as the liaison between industry, government, and consumers. They publish a code of practice for U.S. participants which recommends procedures that are compliant with FDA rules. Ozone is only mentioned once in this 32-page document, regarding disinfection by products, in particular regarding bromate.
Types of Bottled Water
Bottled water can come from a variety of sources which impact how it is subsequently treated, e.g.:
Spring Water
Spring water is water derived from an underground formation from which water flows naturally to the surface of the earth.
Purified Water
Purified water is water that has been produced by in such a way as to conform to the definition of “purified water” in the U.S. Pharmacopeia. Those treatments can include ozonation, reverse osmosis, UV, distillation, or de-ionization. The finished water product is then placed in a bottle under sanitary conditions.
Mineral Water
Mineral water is natural water containing not less than 250 parts per million total dissolved solids. It is distinguished from other types of bottled water by its constant level and relative proportions of mineral and trace elements at the point of emergence from the source.
Sparkling Water
Sparkling bottled water is water that, after treatment and possible replacement with carbon dioxide, contains the same amount of carbon dioxide that it had as it emerged from the source.
Artisan Water
Artisan water is water from a well that taps a confined aquifer.
Well Water
Well water is water from a hole bored, drilled, or otherwise constructed in the ground, which taps the water aquifer.
Bottled Water Regulations
By federal law, the U.S. Food and Drug Administration (FDA) regulations governing the safety and quality of bottled water must be at least as stringent as the Environmental Protection Agency (EPA) regulations that govern tap water. These include Federal Food, Drug, and Cosmetic Act (FFDCA) (21 U.S.C. §§ 301 et seq.) and several parts of Title 21 of the Code of Federal Regulations. Many of these regulations deal with testing and labelling requirements.
Regulation of bottled water is managed through the FDA’s Center for Food Safety and Applied Nutrition. All 50 states and the District of Columbia have delegation agreements with the U.S. Food and Drug Administration (FDA), meaning that when they inspect a bottled water plant they act with the full authority of the FDA. The FDA regulation 21CFR165.110 does not directly mention ozone. Technically, one could simply bottle tap water and most likely meet most of the regulations. This is not common with most bottled water producers going to extraordinary steps to process their source water to high degrees of purity and good taste.
Bottled Water Production and Processing
Each type of bottled water will have different treatment methods. For example, bottling of municipal drinking water will include removal of chlorine that would not be required for other source waters. As noted above several physical processes can be employed including distillation and reverse osmosis. Initial disinfection in the facility will often include UV.
The application of ozonation is often done just prior to bottling. The objective is to provide an additional disinfection barrier to both the water itself as well as the bottle and cap. In some cases, wholesalers of water for bottling will load ozonated water into the tanker trucks to stabilize the water prior to further treatment at the bottling facility. The bottle itself provides the contact time for disinfection, so controlling the transferred dose to the bottle is most important. Since ozone decomposes with a short half-life, the consumer does encounter the ozone.
Small and Large Scale Bottled Water Treatment
Large scale bottled water companies make the Polyethylene terephthalate (PET) bottles, wash them, and fill them in the same plant. Ozone can be used in the bottle washing step, but the nature of the washing process would disengage ozone gas from the liquid. This means that the facility would have to make provisions to handle the off gas to keep a safe environment for workers. In older facilities, ozone was introduced into the water using fine bubble diffusers. The current practice favors venturi injectors. Some smaller producers use a batch method of producing ozonated water by loading a tank with water and ozonating it to a target concentration and starting the filling line.
For continuous production at high rates, a buffer tank is normally employed prior to bottling (see schematic). A challenge is controlling the concentration of ozone going into the bottle. There is a minimum figure to achieve disinfection and an upper limit due to the potential for bromate formation. A typical range might be 0.25 ppm +/- 0.05 ppm. For a bottling rate of 100 gpm, the ozone production rate may be 20-30 g/h and the buffer tank would be 500-1000 gallons.
The process is further complicated by the frequent stop and go of the production line due to problems with the equipment such as bottles jamming. This can lead to the line starting and stopping. This can be compensated for by increasing the volume of the buffer tank and using a dissolved ozone monitor with a PID control loop to modulate the ozone generator output.
Bottlers require different materials of construction based on their quality standards. The highest level is for full sanitary stainless-steel construction including the venturi and booster pump with all the stainless steel getting an electropolished finish inside and out. Flanged connections are required with a preference for tri-clamp connections for easy disassembly.
So, the next time you find yourself drinking bottled water, it’s likely the water was treated with ozone and is safe and healthy.
Cheers!