By Rick Andrew
Water treatment is fundamentally important when it comes to post-mix beverage applications. With post-mix, the locally available tap water is mixed with CO2 and concentrated beverage syrup to produce our favorite soft drinks on site. If that locally available tap water has characteristics that will negatively affect the appearance, odor and/or taste of the soft drink, then that is a problem for consumers, restaurants and soft drink companies. Responding to this market need, treatment manufacturers have developed specialized product lines focused around treatment of water used in post-mix beverage applications.
Treatment of water used in post-mix applications
Sediment filters, carbon filters (including carbon blocks and granular activated carbon), scale-control cartridges, reverse osmosis and hollow-fiber membranes are among the key technologies applied in treatment of water used for post-mix beverage dispensing applications. Others may include softening, UV and ion exchange. Optimal application of these technologies is determined by water treatment professionals based on source-water characteristics and on water characteristics desired for the particular post-mix beverage dispensing application.
Large soft drink companies have many years of experience in the field with various water sources and levels of water quality and they have also performed research into the optimal water chemistry for their specific products. These soft drink producers know exactly what aspects of water chemistry influence the taste of their beverages, both positively and negatively. For instance, they may be very concerned about residual chlorine or chloramines. This knowledge, coupled with knowledge about water treatment technologies, has led to the development of highly specialized products for water treatment in fountain-beverage applications. Along with the developments in products, there has been significant learning among water treatment professionals in terms of applying these technologies to achieve desired treated water quality.
Post-mix beverage dispensing systems
Requirements for commercial modular systems were first introduced into NSF/ANSI 42 in 2005. These requirements were added to address the needs of the unique water treatment equipment market for post-mix beverage dispensing systems. It is clear from the definition of these systems (Figure 1) that commercial modular system requirements were developed specifically for post-mix beverage dispensing applications. Note that these standard requirements are not meant for products used in consumer installations. The reason for this restriction is that these systems are configurable in the field by qualified water treatment professionals depending on local water conditions. Commercial modular systems typically include an array of possible treatment elements that can fit into specially designed manifolds and provide treatment appropriate to a variety of water quality situations. 
This open-ended configuration would be very confusing to consumers and could result in some inappropriate and ineffective installations. One example of an inappropriate installation would be including two dissimilar modular elements in a parallel-flow configuration, thus leading to uneven flow and incomplete treatment. Proper application of commercial modular systems is critical to their effectiveness, which is reinforced by the standard requirement that they be installed by an authorized plumber or authorized agent of the manufacturer. The standard requires that this provision is described on the modular elements themselves (Figure 2).
NSF/ANSI 42 is structured this way in order to allow for a straightforward certification path for these systems that can have so many permutations of configurations in the field. This path includes the ability of the manufacturer to provide claims and capacity information specific to a modular element on the element itself, as opposed to attempting to identify and uniquely name and label each possible system permutation associated with a given manifold system. The manufacturer then has the option to provide a performance data sheet for each modular element, as opposed to being required to develop a performance data sheet for each possible system permutation. Information specific to these modular systems is required to be included in the performance data sheet for these modular elements or systems (Figure 3).
Certification is key
Standards define the characteristics and attributes necessary for products to conform. The evaluation of products to the standard is a different issue. One approach is self-evaluation by manufacturers and self-declaration. With this approach, there is no independence in the evaluation. Independent testing is another option. This can be a good option, as it provides important, independently developed information regarding the product. Certification takes this independent evaluation a step further, beyond testing only, to a more complete evaluation. The advantages of certification include:
Assuring conformance over time. Testing is an evaluation at only one point in time. A simple test does not address changes to the product over time, whether those changes be intentional on the part of the manufacturer, or unintentional changes brought about by the supply chain and unbeknownst to the manufacturer. Some of these changes can significantly impact conformance of the product to the standard. Certification includes evaluation of product changes through documentation requirements, manufacturing facility audits and periodic product retesting.
Complete examination of all product attributes. Certification requires testing of multiple attributes of a product, including safety of materials in contact with drinking water, structural integrity and contaminant reduction, as opposed to a single test focusing on a single product attribute. Certification also helps assure that product specifications and use instructions are adequately and clearly communicated to the professionals installing and maintaining these complex systems.
Accredited evaluation. Accredited third-party certification means that an accreditation body is assessing the certification to assure it is handled appropriately and that all requirements of the certifier’s policies and the accreditation standard are being met through the certification. So, there is oversight on the third-party certifier as a greater assurance of quality in the certification and evaluation process.
Systems needs addressed by certification
Water treatment manufacturers have developed sophisticated and specialized treatment technologies to fulfill the needs of post-mix beverage dispensing applications. These technologies allow qualified water treatment professionals to configure systems that help assure consistent and pleasing taste for post-mix dispensed soft drinks and beverages. It is the combination of effective treatment technology and water treatment expertise that allows this desired outcome of consistent and pleasing taste. If one or the other element is missing, the result may not be as positive.
Conclusion
An excellent tool for helping to assure treatment technology is effective is through accredited third-party certification to the NSF/ANSI DWTU Standards. Certification provides ongoing assurance that the treatment products conform to the full requirements of the standard, including safety of materials in contact with water, structural integrity, contaminant reduction performance and clear labeling and presentation of product specifications and use instructions.
About the author
Rick Andrew is NSF’s Director of Global Business Development – Water Systems. Previously, he served as General Manager of NSF’s Drinking Water Treatment Units (POU/), ERS (Protocols) and Biosafety Cabinetry Programs. Andrew has a Bachelor’s Degree in chemistry and an MBA from the University of Michigan. He can be reached at (800) NSF-MARK or email: Andrew@nsf.org