When we boil it all down (pun intended) virtually every water treatment system includes one or more of five basic water treatment technologies: Mechanical, Activated Carbon, Scale Inhibitors, Ion Exchange (Softening) and Membrane Separation. The challenge becomes choosing the right treatment technology for the specific water quality and application involved.
Often referred to as “pre”, “string” or “sediment” filters, mechanical filtration is designed to trap and hold particulate matter that is suspended (not dissolved) in water. These filters act as a sieve in which the sediment particles are removed from the water as they flow through the smaller, fibrous pores of the filter. The sizes of these pores are measured in “microns”. In Foodservice, typical mechanical filters will be anywhere from 25 down to 0.5 microns. The lower the micron rating, the greater variance of suspended particulates it can remove from the water. Here is a cool reference list of various everyday items broken down by their micron sizes.
Not only does sediment have the ability to create aesthetic problems for beverages, such as turbidity, but it also takes its toll on equipment. Sediment clogs solenoids and valves, and acts as a catalyst for scale by serving as an adhesive for the hardness minerals to adhere and precipitate out. For these reasons, mechanical filtration is always recommended for protecting beverage quality and equipment operation.
Often referred to as “charcoal” filters, activated carbon filtration is the use of carbon materials that have been activated to open up millions of tiny pores within the carbon structure and are able to remove many substances from the water that cause color taste and/or odor, such as chlorine. This removal is done through adsorption; the carbon binds these contaminants to itself through chemical attraction.
Today, virtually all local municipalities utilize some sort of disinfectant, typically chlorine and/or chloramines, which have an adverse effect on beverages and equipment. Hence the reason not many people enjoy drinking tap water. Activated Carbon filters are recommended for all Foodservice applications.
Let me first start by stating, Scale Inhibitors do not reduce the Total Dissolved Solids (TDS) or remove hardness minerals from water. So where you are using a Scale Inhibition filter and have 300 part per million (ppm) of TDS going into the filter system, you will still have 300 ppm of TDS coming out as well. Inhibitor media is designed to ‘interfere’ with the ability of hardness minerals to crystallize and form scale. Polyphosphate is the most common form of scale inhibition used with Foodservice water filters. This media is dissolved when it comes in contact with the water as it flows through the filter, it basically coats the water or sequesters the hardness minerals present, diminishing their ability to form scale. Polyphosphate scale inhibitors (like our IsoNet filters) works very well for ice machines, flash steam ovens, coffee brewers and hot water towers. It is not recommended for espresso machines, fountain beverages or drinking water applications.
TAC resin (like our ScaleX2 media) is another form of scale inhibitor. Unlike Polyphosphate or Softening, TAC resin adds no chemical to the water and requires no regeneration. As hardness minerals come into contact with the resin, they bind together forming nano-crystals on the surface of the media. Once large enough they break free and flow through the water less problematically. This type of scale inhibition works well with Combi ovens (that use steam generators), tankless water heaters, coffee and tea brewers, and espresso machines.
Water softening (Strong Acid Cation resin) is the most prevalent form of ion exchange. This type of water softener utilizes a bed of sodium-charged polymer resin that exchanges the ions associated with hardness minerals (and small amounts of iron) for sodium ions, creating soft water. Many softeners call for routine regeneration (flushing of the resin bed), and sodium replenishment, to maintain consistent performance. Point-of-use softening cartridges (like the QTSFT-3) are simply replaced once their capacities have been exhausted. The primary purpose of this technology is to prohibit scale from forming in equipment. Water softening is not recommended for ice machines, steam cooking equipment, coffee brewers or fountain beverages. It is an appropriate solution for water heaters, tea brewers and espresso machines.
For those of you feeling rather adventurous or curious, here is a good article discussing ion exchange a bit more in depth.
In Foodservice applications this typically is done with reverse osmosis membranes. This is the process of using a semi-membrane to reject the TDS and ions present, sending them away to drain. Typically, reverse osmosis membranes reject greater than 97% of the dissolved solid content present in the water. Water that is this pure is not ideal for commercial equipment or beverages, so a properly designed system either blends back filtered water (with desirable minerals) or remineralizes the water to provide adequate conductivity needed for good beverages and for keeping the equipment protected.
These systems enable operators to produce optimal water quality and have managing control of the TDS levels they use for their equipment and beverages. While it is initially the most costly form of water treatment, it is also has the highest return on investment in the long run as well.
It doesn’t matter whether it’s a restaurant, café or convenient store, once customers start flowing and business is happening worrying about water filters properly performing is not a priority. Foodservice operators just want it to do what it is supposed to do, keep machines protected and beverages tasting good. For this to happen, it’s imperative that the right technologies are used for the right applications. Understanding these five basic technologies will go a long way in ensuring that your applications are being treated properly. Our product catalog is free to download and also does a great job breaking down and identifying the right technology for the right application.
Photo shout out: Frank Kovalchek
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