Softening hard water to help the homeowner use less soap and the business owner avoid boiler scale was the bedrock of the original water treatment industry and in many communities remains the number-one reason to seek the services of a water treatment dealer.

But in recent years, as more communities have faced the question of managing brine discharges into wastewater treatment systems (see: “Softener bans: Is the tide turning?” in the September 2006 Water Technology®), a new challenge has been raised for developers of water softening systems: eliminate, or at least radically reduce, salt use.

That may be a tall order, but it raises the broader question of where softening technology is headed. Water Technology recently interviewed several industry experts to get their views.

The consensus: For the near future — say, the next five or 10 years — the gradual improvements in ion exchange technology that have marked the last several decades will continue to be the norm. However, the industry will be working harder than ever to minimize salt consumption in its systems, and no one can rule out the possibility of a scientific or conceptual “leap” outside the realm of ion exchange.

Defining a ‘leap’
Joe Harrison, technical director of the Water Quality Association, says that someone who can come up with an effective way to soften water without using salt would create a significant new technological leap for the industry.

“So far, I don’t think we’re there,” Harrison says, while noting that demand-initiated regeneration (DIR) controls and other developments have moved things along.

Some of the recent developments in membrane and similar filtration technologies can remove some hardness factors, but concerns such as cost, pretreatment requirements and membrane maintenance have to be considered, according to Harrison.

Efficiency the goal
Advances in softening technology have been evolutionary, rather than revolutionary, and are likely to continue that way, according to Dr. Frank A. Brigano, vice president of research and development at Culligan International Co., the Northbrook, IL-based water treatment manufacturer.

“What’s brilliant about [ion exchange] water softening is that it’s so efficient at what it does,” Brigano says. “It targets only the hardness ions.”

He adds, “Most water softeners are about 95 percent efficient” in terms of their performance and water usage. “Now it’s a matter of getting those efficiencies even higher.”

Brigano believes, as do others, that the basic chemistry of water softening is still a “given” that the industry must work with.

“No matter what technology you use in exchanging ions in the water, you’re always going to have a discharge of solids. Those solids have to go somewhere, so it’s a matter of improving the efficiency” of the process that produces those solids, he says.

From ions to crystals
Steve Fox, an industry veteran and president of Next™ Filtration Technologies, Inc., a three-year-old water treatment systems manufacturer based in Lake Worth, FL, thinks his company’s recent development may provide a “paradigm shift” in water conditioning, and expects dealers to add it to their existing lines of traditional ion exchange softening systems.

As Fox explains it, Next’s technology involves creation of nucleation sites on a polymer bead to which calcium and magnesium ions, which cause water hardness, are attracted and form micro-crystals. The crystals slough off the beads as water passes up through them and flows along with the water wherever it goes.

The micro-crystals are nano-sized and too small to be filtered out. The net effect, according to Fox, is that the hardness is essentially a benign particle which stays in solution instead of forming scale on any other surface.

Fox notes that while traditional ion exchange softening removes all hardness ions to achieve virtually scale-free water, Next’s technology transforms the hardness so that it does not form scale but retains what could be regarded as beneficial minerals. Fox said the technology has been rated as 99.6 percent effective in preventing scale by the prestigious German testing authority DVGW.

Fox said the technology has been well-received by dealers and their customers for residential applications but the hotel, apartment and office building market has drawn the most attention.

The company says that the technology requires no regenerant (such as salt or other chemical) for the media and produces no discharge. It recommends that the polymer-bead media that forms the basis of the system be changed about every three to four years, depending on chlorine and potential foulants in the water such as iron.

He calls it a “simplified, non-polluting and cost-effective technology.”

Fox says, “Softening and ion exchange are not going to go away, but we think we have a huge potential in the market that is now dominated by ion exchange.”

Raising the resin bar
The fact that some communities have banned or are trying to ban water softeners due to concerns about brine discharges doesn’t foretell the end of ion exchange, says Gary Schreiber, CWS-VI, Midwest sales manager for The Purolite Co., a manufacturer of ion exchange resins with offices in Bala Cynwyd, PA. Schreiber has been a long-time observer of softening technology.

Portable exchange tank services, although historically one of the earliest types of services provided by dealers, are still an option for communities where brine discharges are banned, he says.

But Schreiber also points to advances in resin technology. As one example, he notes that his company has for the past eight years marketed a type of “shallow-shell” resin bead that, he says, allows for faster ion exchange, regeneration with very low salt doses, shorter rinse cycles and less susceptibility to iron fouling.

As Schreiber explains it, this type of bead is “functionalized,” or made chemically functional, only on its outside layer, making it more efficient overall in the ion exchange process.

“You can get similar results with fine-mesh resin, where the functionality (ion exchange) is very rapid, but fine-mesh resin beds give you more of a pressure drop,” he says.

Several other companies also continue to advance resin technology, and the new regulatory push for arsenic removal also appears to be an incentive for further resin improvements.

Still up in the air
Overall, Schreiber says, “The [water treatment] industry is looking to all kinds of ways to reduce salt. It’s going to be an evolutionary process,” He says DIR and new resins are among the more recent stages of that process.

Some say there may be some evidence that magnetic technology is effective in reducing hardness-related pipe scale in continuous-flow, closed-loop circulation systems like boiler or cooling tower applications. However, its effectiveness in softening applications for home or commercial water consumption remains at least an open question.

Magnetic water conditioning has traditionally drawn skepticism from many in the industry, who continue to await harder scientific proof of its effectiveness.

“Because water doesn’t form scale doesn’t necessarily mean it’s been softened,” Schreiber says. “The calcium and magnesium may still be there, and can still affect soap.”

Must be provable
With any new water treatment technologies that are developed, including those affecting softening, the science and chemistry must be “clear and defined,” Culligan’s Brigano says, and those technologies and the data that support them must be able to be easily validated according to widely accepted industry standards.

“Obviously, the key is efficiency in salt usage and water usage,” Brigano says.

As one example of an effort in that direction, Brigano says Culligan has developed a sensor system, in which a probe inside the resin bed monitors the resistivity of the water, which is a function of the concentration of certain ions. The probe sends a digital signal to the softener valve to activate regeneration and rinsing.

What the system ‘knows’
With such a digital sensor device, Brigano says, the water system “knows” from a chemical standpoint exactly where the resin bed exhaustion front is — that “front” being the point when the resin beads have reached a certain limit in their ability to exchange sodium ions for calcium and magnesium ions. The control also “knows” when it is time to start the regeneration cycle.

Probe technology that meters chemical variables in softeners is not new, according to Brigano, but the recent refinements involving digital technology instead of analog allow greater fine-tuning.

Several manufacturers now offer valves and controls with programmable digital options, to help the water system owner customize salt consumption.

Mike Hamberger, national sales manager of Water-Right, Inc., an Appleton, WI-based manufacturer of water conditioning systems, says more computer technology could be applied to all kinds of water treatment, include softener controls.

There’s now a much wider variety of problem well waters being encountered by people moving to rural areas, Hamberger says. That’s creating demand for more “intelligent” systems that can tackle more complicated mixes — of contaminants, hardness minerals, TDS and pH — than a basic softener suitable for municipal water.

Staying awhile
Clearly, ion exchange technology is here to stay awhile, and for some good reasons.

“The advantage of ion exchange softening is that it’s very complete and very robust,” WQA’s Harrison observes. “It can be used in a very wide variety of water conditions, with many variables, and it still works.”

Although he and others don’t think ion exchange technology will ever be replaced, they also understand that any technology never stands still.

As Harrison puts it, “They’re working on it.”