By Rick Andrew
Think about the taste of your favorite soft drink. It’s easy, isn’t it? The taste is always the same, whether the soft drink was purchased at a retail store in Omaha or Raleigh, or from a fountain outlet in Tuscaloosa or Kalamazoo. Taste is critical to soft drink companies, who brand their products based on unique and consistent good taste.
Now think about the taste of water. As we all know, there is significant variability in the taste of water from one region to another, from treated surface water to well water, and all variations thereof. How is it that the soft drink companies are able to achieve the consistent, pleasing taste they need to effectively brand their products when the main ingredient is so highly variable in its taste characteristics? Through treatment, of course!
Water treatment technologies for foodservice applications
There are a number of water treatment technologies widely used for foodservice applications. These technologies commonly include sediment filters, carbon filters including carbon blocks, scale control cartridges, reverse osmosis and hollow fiber membranes. There are undoubtedly others.
These technologies are applied based on source water characteristics, and on desired water characteristics for the particular foodservice application. Optimal water chemistry for making coffee and tea differs from optimal water chemistry for making carbonated soft drinks.
Most large beverage companies have performed extensive research into the optimal water chemistry for making their specific products. Large soft drink producers know exactly what aspects of water chemistry influence taste, both positively and negatively. They may be very concerned about residual chlorine or chloramines, for instance. Large coffee and tea producers have very different concerns such as levels of total dissolved solids and hardness, for example.
This knowledge, coupled with knowledge about water treatment technologies, has led to the development of highly specialized products for water treatment in foodservice applications.
Incorporation of commercial modular systems into NSF/ANSI 42
NSF/ANSI 42-2005e includes the addition of requirements for commercial modular systems. These requirements have been added to address the unique foodservice water treatment equipment market. The definition of these systems can be found in Figure 1.
Note that commercial modular systems are intended specifically for foodservice applications and are not meant for consumer installations. The reason for this restriction is that these systems are configurable in the field to treat the water as needed. There can be an array of possible treatment elements that can fit into these manifolds and provide a variety of functions across multiple use patterns. This open-ended configuration would be very confusing to consumers and could result in some very inappropriate installations. A prime example of a potentially flawed application would be the installation of two dissimilar modular elements in parallel. This is not a good idea because a disproportionate flow between these elements could result, especially if one modular element is a cyst filter and the other is not. Also, in a situation with dissimilar elements in parallel, the entire water stream may not get the expected treatment, such as cyst filtration. Treating only part of the flow for cyst reduction doesn’t make much sense, as even one cyst passing through the system can be enough to cause harm.
These potential consumer installation pitfalls are avoided with proper application of commercial modular systems, because they are required by the Standard to be installed by a water treatment professional or licensed plumber. This requirement is made clear on the system manifold, and on the modular elements themselves, as described in Figure 2. 
Beyond just ensuring minimal functionality, these expert installers can optimize the configuration of modular elements for the flow requirements, treatment needs and water chemistry of the particular installation.
The advantage of these new provisions in Standard 42 is to allow for a straightforward certification path for these systems that can have so many permutations on their capabilities 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. The configurable manifold that forms the backbone of the system is certified as a component of the system, meeting the Standard requirements for material safety and structural integrity. Additionally, the manifold must be sized such that velocity through it does not exceed 10 feet per second. This requirement helps ensure even flow through identical modular elements installed in parallel.
The manufacturer then provides a performance data sheet for each possible configuration of the modular system, providing the information included in Figure 3 
in addition to the information typically required on a performance data sheet.
These provisions greatly simplify certification of these systems. Prior to adoption of these requirements, replacement elements including commercial modular elements had to include on their packaging an indication of which system model number they fit into. Because commercial modular elements fit into many different systems, this was very difficult to accomplish. Another requirement of replacement elements is to have the system capacity and flow rate indicated on their packaging. This was very difficult to implement for the numerous permutations of commercial modular systems that can have variable flow rates and capacities resulting from their multiple modular elements and has effectively been addressed with the adoption of the new requirements regarding labeling of modular elements.
NSF/ANSI DWTU Standards: serving specific foodservice needs
Water treatment manufacturers have developed highly specialized products to suit the needs of the foodservice industry. Much the way chain restaurants strive to provide a consistent meal from location to location, national soft drink and other beverage producers have great interest in delivering products with a consistent, branded taste. It is rare, if ever, that we encounter an off-tasting nationally branded soft drink or coffee.
The consistent taste delivered by beverage companies is not only an indication of their commitment to quality, but it necessitates an understanding of the water chemistry parameters that influence taste, a knowledge of how to treat those parameters and a proper application of water treatment technologies.
As these technologies have developed into today’s highly specialized products, the NSF/ANSI Drinking Water Treatment Units Standards have evolved to provide a smooth certification path that helps address the field-configurable nature of these products, while maintaining consumer safety and protection of public health as the primary focus.
About the author
Rick Andrew has been with NSF International for over six years, working with certification of residential drinking water products. He has been the Technical Manager of the Drinking Water Treatment Units Program for over three years. His previous experience was in the area of analytical and environmental chemistry consulting. Andrew has a bachelor’s degree in chemistry and an MBA from the University of Michigan. He can be reached at 1-800-NSF-MARK or email: [email protected]