UV Disinfection in the Beverage and Bottled Water Industries
Effective microbial disinfection in the processing of beverages and bottled water is essential. A non-chemical disinfection method which is gaining increasing acceptance is ultraviolet (UV) disinfection. UV kills all known spoilage microorganisms, including bacteria, viruses, yeasts and moulds (and their spores). It is a low maintenance, environmentally friendly technology which eliminates the need for chemical treatment while ensuring high levels of disinfection.
UV Disinfection in the Beverage and Bottled Water Industries
How UV disinfection works
UV is the part of the electromagnetic spectrum between visible light and X-rays. The specific portion of the UV spectrum between 185-400nm (known as UV-C) has a strong germicidal effect. At these wavelengths UV kills microorganisms by penetrating their cell membranes and damaging the DNA, making them unable to reproduce and effectively killing them. Virtually any liquid can be effectively treated with UV, including raw mains water, filtered process water, viscous sugar syrups, beverages and effluent.
There are no microorganisms known to be resistant to UV – this includes pathogenic bacteria such as Listeria and Cryptosporidium (and its spores, which are resistant to chlorination).
There are two main types of UV technology based on the type of UV lamps used: low pressure and medium pressure. Low pressure lamps have a monochromatic UV output (limited to a single wavelength at 254nm), whereas medium pressure lamps have a polychromatic UV output (with an output between 185-400nm).
Benefits of UV Disinfection
UV disinfection has many advantages over alternative methods. Unlike chemical treatment, UV does not introduce toxins or residues into process water and does not alter the chemical composition, taste, odour or pH of the fluid being disinfected.
UV treatment can be used for primary water disinfection or as a back-up for other water purification methods such as carbon filtration, reverse osmosis or pasteurisation. As UV has no residual effect, the best position for a treatment system is immediately prior to the point of use. This ensures incoming microbiological contaminants are destroyed and there is a minimal chance of post-treatment contamination.
Bromates and bottled water – UV as an alternative to ozonation
Hanovia has been working with most of China’s leading bottled water producers, including Nongfu Spring Co. Ltd., to supply them with UV systems for their production plants. This is a significant development in the bottled water industry – particularly in China – because until recently virtually all bottled water in that country was disinfected using ozone.
The decision by Chinese bottled water producers to opt for UV was driven by a number of reasons, not least of which are concerns about ozonation by-products such as bromate. Bromide ions occur naturally in many spring waters and pose no problem on their own. However, the presence of ozone in the water can cause the conversion of bromide into bromate – a compound classified by the Health Organization (WHO) as a carcinogen. The WHO recommends a maximum limit of bromate in mineral water be set at 0.01mg/l (10ppb).
In July 2008 the Chinese General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ), recommended in a revised draft national standard for drinking water and mineral water that a maximum limit for bromate in bottled water be in line the WHO guidelines. This new limit has been in force since October 2009.
Case Study – Angel Springs Limited, United Kingdom
Angel Springs Limited, situated near London in the United Kingdom, bottles natural spring water for use in water coolers. The company replaced its ozone water disinfection unit with a Hanovia UV system several years ago, mainly due to concerns about bromate. Even though bromide ion levels in the source water are not particularly high, the company decided to go for the safer option and use UV instead.
Angel Springs’ water originates from a natural spring on the site. After filtration to remove physical particles it passes through the UV chamber and is then bottled. There is no further water treatment and no chemical treatment.
Other UV applications in beverage and bottled water production
Municipal and natural spring water
Although municipal water supplies should be free from harmful microorganisms, this should not be assumed. In addition, water from natural springs could also be contaminated. Any water used as an ingredient in beverage products or for bottling can therefore be a source of contamination. UV disinfects this water without chemicals or pasteurisation.
Sugar syrups and sweeteners
Sugar syrups and sucrose-based sweeteners can be a breeding ground for microorganisms. Although syrups with very high sugar contents do not support microbial growth, any dormant spores may become active after the syrup has been diluted. Treating syrups, sweeteners and dilution water with UV prior to use will ensure any dormant microorganisms are destroyed.
CIP (Clean-in-Place) rinse water
It is essential that the CIP final rinse water used to flush out foreign matter and disinfecting solutions is microbiologically safe. Fully automated UV disinfection systems can be integrated with CIP rinse cycles to ensure final rinse water does not reintroduce microbiological contaminants.
Filtered water disinfection
Stored reverse osmosis (RO) and granular activated carbon (GAC) filtrate is often used to filter process water, but can be a breeding ground for bacteria. UV is an effective way of disinfecting both stored RO and GAC filtered water and has been used in the process industries for many years.
Dechlorination
GAC filters have traditionally been used to remove free chlorine from feed water supplies before treatment through RO membranes. However, the major drawback with GAC filters is that, with time, the carbon material becomes a breeding ground for bacteria and begins to elute harmful microorganisms into the process water. It is now becoming more acceptable to use UV to destroy the chlorine – not only are UV dechlorination systems more hygienic, they also occupy a smaller footprint than GAC filters and require much reduced capital and operating costs.
Waste water and process water
Effluent from beverage and bottling facilities can be treated with UV, avoiding the need for environmentally damaging chemicals and ensuring all discharges meet with local environmental regulations. Process water can also be treated and re-used with UV, resulting in a significant reduction in the amount of waste water produced.
Conclusion
Meeting the rigorous hygiene standards required in the production of beverages and bottled water products can be challenging. For manufacturers seeking to guarantee the quality of their end product, UV is an economic, environmentally friendly option. It is already widely used in high purity applications like pharmaceutical processing and microchip manufacturing, where water of the highest quality is required.
UV disinfection systems are easy to install, with minimum disruption to the plant. They need very little maintenance, the only requirement being replacement of the UV lamps every 12 months or so, depending on use. This is a simple operation that takes only a few minutes and can be carried out by general maintenance staff.
THE UV PROCESS WHICH HAS BEEN GIVEN HERE IS A VERY EFFECTIVE, ECONOMICAL AND ECO-FRIENDLY PROCESS. IT IT IS REALLY WORTH TO BE ADOPTED WIDELY. CAN YOU PLEASE TELL ME IF OZONATION FOR THE BOTTLED WATER IS NOT AT ALL REQUIRED WHEN WE DO UV PROCESS? DOES THIS GIVE ALL RESIDUAL EFFECTS OF OZONATION?
ASHWINI AWASTHI
MOB : +91 9326569426
UV treatment of bottled water production is widely accepted and used. Since UV can destroy all organisms it can be used to totally replace ozone for disinfection. However, if the bottling plant does not have aseptic PET filling, some users prefer to use a small amount of ozone before filling, to take care of any problems with the cap and lip in conjunction with Hanovia UV used further upstream. By using Hanovia UV as the primary disinfection, the amount of ozone used can be reduced well below the level that can cause bromate formation.