Necessity is the mother of invention
The water treatment industry is a highly evolved technology, but it did not evolve from a single great fountain of knowledge. Nor did it evolve in a single direction. Each branch of the industry (residential, commercial and industrial) has its own reasons and needs; the level of sophistication in the design of the treatment technologies unfolded to the level required to meet those specific needs. Softening has been with us for over 100 years but the degree of performance expected from a softener differs according to the job it has to do. Residential softeners had the need to be bullet proof. Today’s systems are operated by highly reliable control valves that the owners never have to fix or adjust.
The food service industry utilizes hot water softeners for dishwashing that do very well with high temperature tanks and valves; however, the residential, commercial and industrial markets rarely use hot water softening. Hotels use high flow systems that are able to handle very high peak flows with minimal pressure drop and still provide very soft water for critical applications such as boiler feeds and kitchen use.
The industrial market centers on performance and it probably employs the most highly evolved systems of all, but little of the technology and sophistication of those industrial systems ever carries over into the other markets.
Since each market has followed a different path of evolution, we must ask the question: “Does the design experience gained from one market segment provide a springboard when a business seeks to expand into a different market?” The answer, unfortunately, is, “Not really.”
Different industries have different needs
For residential applications we tend to view the water softener as an “appliance”. Sure, it saves you money over the long haul and provides a lot of convenience and protects appliances. BUT…there are tens of millions of homeowners around the world that do not have softeners and get along just fine. A softener for the home is not a necessity, it’s a preference, depending on location.
Commercial applications for softeners include hotels, restaurants and car washes. Indeed, they can measure the benefits of having softened water in direct labor savings, wear and tear on linens, not having to polish off unsightly water spots, etc. But again, there are countless hotels and restaurants and car washes in areas with hard water that operate successfully without a softener and make up the difference in labor costs. For many commercial applications, the softener is also not a necessity.
Industrial applications for softeners – which include moderate pressure boilers, some electronics, metal plating and pre-treatment for reverse osmosis, tend to view a water softener as a highly engineered and integral step in the total treatment of the water stream. If the softener fails to work properly, the economic consequences can be severe. It is a necessity. We can, therefore, define the philosophical differences between residential, commercial and industrial water treatment in terms of the consequences of failure.
What separates industrial water treatment applications apart from residential and commercial are the consequences of failure.
Physically, water softening equipment designs differentiate themselves by the following characteristics:
- reliability of performance
- hydraulic design
- methods of monitoring
- levels of maintenance
Assessing the risk of failure
This is not to say that the home softener is not well designed and unreliable. It is simply the consideration of “what happens if it’s not?” Maybe you get water spots on dishes, scratchy towels and soap scum in the tub but there are tons of products that can be used to minimize the “damage, ”which is largely cosmetic. Commercial applications can be thought of as larger versions of those home units in many of their design characteristics. There are, however, more severe economic consequences in labor and maintenance costs if the system does not properly function and those costs are easily measured. Boiler blow down is increased which wastes heat, water and power. Water spotting creates doubts among diners as to cleanliness of dishes and flatware and may cost in losses of repeat business. More busboys may need to be on the dinner shift to polish the spots off of the glasses before they head out to the bar. Car washes must thoroughly hand dry vehicles, thus, increasing labor costs. No doubt, the cost of failure is higher for most commercial operations than for residential, but those costs are not catastrophic and do not shut down the operation…at least not right away. Nonetheless and despite the similarities in design, commercial equipment must perform more reliably and the builder must be able to point to those differences which ensure that it will.
There are philosophical differences perceived by the buyers and users of industrial water treatment equipment. You don’t “graduate” into the industrial market. You have to “grow” into it by experience.
Many residential/commercial equipment suppliers will venture into the commercial/industrial arena and at first, feel they have a considerable advantage because they know how to build economical equipment. Their bids are one -third the amount of the “big boys.” Yet they seldom win those bids – because their offerings do not meet the more stringent requirements and expectations of industrial design. Industrial systems often seem oversized and underutilized. Who needs all that back up? Why is there a need to shut down the system and switch to a back up just because of 1 ppm of hardness leakage? More importantly, …how do they know they have 1 ppm leakage? My test kit gives results in grains (17.1 ppm hardness).
This article will attempt to discuss the philosophical differences that are perceived by the buyers and users of industrial equipment and compare it to the “typical” performance requirements of residential and commercial equipment. By the way, rule #1 is that the perception of need is reality.
Most consumers take a high level of pride in ownership and love superlatives ..i.e., words ending in “est” like biggest, baddest and best. If they own a big house with a five car garage, they feel the need to fill all the bays and there are plenty of merchants around who will “accommodate” them (paraphrasing P.T. Barnum). Likewise, they need a “big” water treatment system. If they have five bathrooms and two kitchens with a fixture count of 30 gpm and 1 ½ inch plumbing, it won’t be hard to convince them to put in the king-sized twin alternating dilly deluxe softener even though there are only four people in the family and one of them is still in diapers.
One of the more serious flaws in the plumbing codes is that we have to provide residential systems that meet the perception of need of some engineer who doesn’t even own a home rather than the real needs of the consumer. This practice brings about waste, extra costs and often, poor performance (systems can be too large to function at the low flows). For the life of me, I find it difficult to see how any normal family can consume more than 100 gallons of water a day per person (excluding irrigation). Flow demands in even larger homes will rarely exceed 3 gallons per minute. With 20 grains of hardness, this 400 gpd family has to deal with 8000 grains of hardness which would exhaust a typical one cubic foot softener in three days. A system sized for this fixture count will last weeks and may not only channel and deliver hard water but a pretty good bacteria count as well.
What does any of this have to do with the “consequences of failure?” The fact is, residential users do not need zero hard water. Even by definition, water containing a grain or two of hardness is considered to be soft. The oversized system described above works because it creates the perception of a quality piece of equipment….even if it only works part of the time. Residential systems are usually not the limiting factor in total water flow nor are they regularly monitored. They require little maintenance. If the controls are improperly set, no one is wiser. They are often given a lifetime warrantee and if they fail, it can be several days – maybe weeks – before the homeowner is even aware of it (plus, they will run out of salt at least three times per year and hardly notice). Once a residential system is sold, the manufacturer usually makes no follow-up service call to see whether and how the system is working. Carry this attitude into the world of industrial equipment and there will be problems.
One of the main reasons an industrial equipment designer rarely uses residential equipment or components is because of the constant need to make adjustments in the operation. Top mounted controls don’t lend themselves to owner maintenance or adjustment. Residential systems are often fed by city water pressure. Pressure drop is not something one has to pay for; in an industrial system, it generally is.
Such systems are, therefore, designed with lower flows to reduce the pressure drop. The lower flow is also more efficient for resin utility and salt usage or brine efficiency. Industrial systems have the advantage of generally operating at close to design flows which are fairly constant and continuous. That way, they can design the distribution system for precise flow, which produces a better regeneration and lower leakages. Since leakage requirements on industrial systems often call for less than 0.5 ppm hardness, there is a need to monitor. This creates the need for more diligent maintenance. Industrial systems are often merely one step in a long process and if the step breaks down, tens of thousands of dollars are lost in reduced production, rejects or equipment damage. The results tend to be immediate and catastrophic. Hence, the need for system reliability and redundancy of equipment becomes more apparent.
So, what kind of guidelines can be suggested for building a good industrial softener? Unfortunately, there are no ready references or how to’s on good or proper industrial design. One generally acquires this information “on the job.” I had mentioned at the outset of this article that I would discuss the philosophical differences perceived to be more proper for industrial design. This will include the four things I mentioned: hydraulics, reliability, monitoring and maintenance. Proper design is purely a matter of need (perceived or real). Industrial processes are simply more sensitive to hardness scale problems than is either residential or commercial.
Everyone involved in the sale or supply of a product likes to think they are offering the best available. If we clarify that by adding “for the price”, we have a more correct statement. The fuel pump in your automobile is cheap and reliable. The car won’t run without it. But it’s not as reliable as the fuel pump in the space shuttle or the insulin pump imbedded in someone’s abdomen. How many times have you had hand tools fail because the switch broke? Ah…the weak link. Murphy’s Law. In the industrial market, reliability implies total system reliability. A 20-year life is the norm and the system has to perform as well on its last day of service as it did on its first. Reliability must be built in at the start. It is prohibitively expensive to add it in later.
The reliability of a system is only as strong as its weakest link.
Residential water treatment equipment designs do not automatically give birth to commercial designs which, in turn, do not lead to industrial designs. Not only are there physical differences but philosophical concept differences as well. These designs differ in their areas of reliability, their hydraulic limits, how they are monitored and how they are maintained. Part II of this article will compare these physical differences and offer guidelines for making the transition from one to the other.
About the author
C.F. ‘Chubb’ Michaud, CWS-VI, holds bachelor’s and master’s degrees in chemical engineering from the University of Maine and has more than 30 years of professional experience in water and fluid treatment processes. Michaud is technical director for Systematix Inc. of Buena Park, CA. He also is chairman of the Water Quality Association’s Ion Exchange Task Force, sits on the Science Advisory Committee and is a founding member of the WC&P Technical Review Committee. Michaud can be reached at (714) 522-5453, (714) 522-5443 (fax) or email: [email protected].