Water Treatment in the Beverage Industry

 

Unique Needs

 

Product Quality

 

Soft drink production starts with a pure source of water. Regular soft drinks contain 90 percent water, while diet soft drinks may contain up to 99 percent water. Drinking water often includes trace amounts of various elements that affect its taste. Bottlers use filtering and other treatment equipment to remove residual impurities and standardize the water used to make soft drinks, so that soft drinks taste the same nationwide.

 

Regulatory

 

Beverage production is monitored by the FDA. Yet manufacturers say that the best practice for water treatment for the beverage industry is based on some now antiquated guidelines put forth in 1993. These guidelines donít cover the use of membranes.

 

Health & Safety

 

Health and safety in manufacturing and final product is key. Beverage manufacturers need to protect their consumers and their own employees.

 

In August 2006 Indiaís Center for Science and the Environment announced that drinks manufactured by Coca Cola and Pepsi companies in India contained on average more than 24 times the safe limits of pesticides. In India the soft drink industry is virtually unregulated. It is up to the manufacturer to ensure that the process water is clean.

 

Out of specification events contribute to contamination scares. In March 2004, only weeks after it introduced Dasani bottled water into Britain, the Coca-Cola Company ordered a recall of some 500,000 bottles after finding excess levels of bromate. The process used to purify Dasani water relied on calcium chloride, which contained levels of bromide. Bromide, in turn, produced traces of bromate during a part of the purification procedure, in excess of British law of 10 parts per billion. Manufacturers need to find ways to eliminate these occurrences.

 

Treatment Technology

 

One of the options available to beverage processors is the use of ultraviolet water treatment systems. UV radiation purifies the water without adding undesirable color, odor, chemicals or taste - and there are no residual byproducts. It is fast, effective, efficient and environmentally friendly.

 

The typical locations within a beverage water system where UV equipment may be installed for disinfection are the post-carbon filter and pre/post-RO.

 

Ozone is commonly used in the beverage industry to sanitize storage tanks, vessels, piping and auxiliary equipment such as pumps and valves in order to eliminate bacteria. The residual ozone needs to be destroyed prior to point-of-use to ensure product quality. UV technology is the technology of choice for this application since it provides instant results without the complications of chemical additives and the byproducts they leave behind. The size of the UV equipment required to completely destroy the residual ozone present in a water stream depends on the flow rate, ozone concentration, quality of the feedwater and the temperature of the water stream.

 

Penta water undergoes a 13-step purification process. This process far exceeds FDA standards for bottled water, as well as many other bottled water manufacturers. It is designed to remove every possible impurity found in water, including arsenic, bacteria, chlorine, fluoride, lead, MTBE, and pesticides. No chemical additives, such as chlorine, are used. They begin with regular water that measures approximately 550 parts per million (ppm) of total dissolved solids (TDS). At the end of this 13-step purification process, the TDS will average about 0.5 ppm.

 

Technology Steps

Target

Ultraviolet light (UV) 1st pass

Bacteria and TOC

Multimedia filtration (depth filter)

Sediment particles

Granular activated carbon (GAC) filtration

Chlorine and bromine

5-Micron filtration

Particles, some bacteria

Reverse osmosis (1st pass)

TDS down to 5 ppm

Reverse osmosis (2nd pass)

TDS down to 1.3 ppm

Deionization

Removes ions, TDS down to 0.5 ppm

1-Micron filtration

Bacteria <5 Ķ (such as E. coli)

.2-Micron filtration (1st pass)

Bacteria < 1 Ķ

Ozonation

Microbes

Patented Penta process

Raise boiling point & viscosity

.2-Micron filtration (2nd pass)

Bacteria

Ultraviolet light (UV) 2nd pass

Bacteria and TOC

 

In 1994 Coca Cola initiated a total water quality management program. The Coca-Cola Company makes mandatory in Coke plants the franchisor's long-established Multi Barrier System (MBS) approach for removing all potential contaminants from incoming water supplies. The five steps of this approach are 1) enhanced filtration (pathogenic microorganisms); 2) alkalinity reduction, if needed (taste); 3) disinfection (secondary barrier against microorganisms); 4) carbon purification (chlorine, organics for safety and taste); and 5) polishing filtration (carbon fines).

 

Technologies employed at various stages of the MBS can include coagulation, flocculation, sand filtration, nanofiltration, ultrafiltration, ion-exchange, electrodialysis, chlorine and ultraviolet (UV).

 

According to at Marcio Amazonas, Global Quality Water Resources Manger at Coca Cola, no matter the source, Coke will treat incoming water with chlorine. They usually use calcium hypochloride here in the West. UV is becoming more widely used at Coke bottling plants.

 

Enhanced filtration is carried out at the molecular level. Coke addresses this two ways, chemically or physically depending on the quality of the water at each specific plant. Chemically they rely on coagulation and flocculation. Plants that utilize cleaner water sources use in line flocculation which doesnít require a separate reactor area for chemical treatment. Lime is often used because CSDs require low alkalinity. In line plants may also require ion exchange to remove individual contaminants like arsenic.

 

For physical filtration Coca Cola uses membranes, and mostly at the UF pore size level. Smaller pore sized RO membranes are problematic because of energy requirements, and also because of the volume of wastewater generated.

 

Carbon filtration is used to remove organics and gases, which membrane separation doesnít filter out.

 

The last polishing step is generally microfiltration, which is used to filter out any carbon that might have leached into the beverage.

 

The treatment for Dasani bottled water is also standardized throughout the West. Coke utilizes a double pass RO system followed by ozonation.

 

Water technologies managers in corporate quality at The Coca-Cola Company, see use of UV growing in the MBS approach. UV has been used effectively in Europe for some time and in 2001 the USEPA considered LTV a valid technology to reduce microbial loads. In general, there has been a shift away from chemical types of water treatment toward more physical treatment technologies.

 

As RO systems become more prevalent in the beverage industry, they're being used to treat water supplies where sub5-micron particles in the feed water are plugging them. Conventional treatment with multimedia filters and cartridge filters will not remove these particles. There has been a transition away from multimedia filters and toward continuous microfiltration or ultrafiltration as a pretreatment to these reverse osmosis systems.

 

Pepsi's bottled water Aquafina developed the HydRO-7 purification process. It consists of:

Step 1: Prefiltration

Step 2: Polishing Filter

Step 3:  High Intensity Light

Step 4: RO to remove 98% of Total dissolved solids from the water

Step 5: Charcoal Filtration

Step 6: Polishing Filter

Step 7: Ozonation

 

Maintenance and Operation Considerations

 

The RO system can be troublesome to maintain and operate. According to David H. Paul, President of David H. Paul Inc., biofouling control of RO units can be a challenge even when the feed water is pretreated with chlorine and UV. Chlorination followed by dechlorination converts organic molecules that bacteria canít use as food into a higher percentage of organic molecules that they can use as food. In other words, chlorinated/dechlorinated feed waters will grow more bacteria in an RO unit than if the feed water was never chlorinated to begin with.

 

An RO unit can have horrible biofouling even with UV pretreatment. While UV radiation is certainly effective for inactivating the bulk of feed water bacteria, the number of bacterial cells entering the RO unit does not change with UV pretreatment. Dead bacteria that do not exit in the concentrate stream decompose to become food for living bacteria.

 

At certain facilities biofouling control has been maintained by regular heat sanitizations of the RO units (containing heat-sanitizable membrane elements). Greatly oversized (based on chlorine demand) activated carbon beds have been reported to minimize RO unit biofouling due to removal of organic food molecules.

 

The challenges the Coke and other beverage producers still face is that of microbiological testing and contamination. The test methods developed in the 1940ís and 1950ís have not kept up with the development of chemicals used throughout the water treatment system.

 

Undesirable Byproducts

 

The debate over chlorine is ongoing. The health risk of daily exposure to chlorine in drinking water vs. the dangers of drinking water containing disease-causing pathogens prevails as a major issue.

 

The most effective way to control bromate formation is through removal of bromide ion from raw water. For drinking waters treated by distillation, demineralization and reverse osmosis, this is easily achieved. However, for natural spring waters or natural well waters, any process that alters the original chemical composition of the source water is not permitted.

 

Costs

 

Capital costs vary for the system configurations and technologies used. Paul Greene, Global Director - Food & Beverage Industry of Siemens Water Technologies says that depending on water quality coming in, the purity required and the level of sophistication of the equipment desired (plastic vs stainless steel piping) prices can range from about $1500 per gpm up to $3000, excluding installation costs. Siemens carries a range of configurations starting from systems as small 1 gpm.