Residential Water Treatment: From the Cave to the Suburbs
Contending that water plays an important role on our planet is the ultimate understatement. Without water, life as we know it could not exist. When investigating the possibility of life on Mars, we first look for evidence of water. No water, no life, next topic please. Find evidence of water and it follows logically to consider looking for further signs of life. The vast complexities of chemistry need not be comprehended. The need for water is a given, so let’s move on to how humans have perceived water and attempted to make this resource more palatable.
History of Water Purification
Ancient civilizations pondered the dichotomy of having no rainfall for months, yet experiencing floods during this otherwise dry era. How did the rivers continue to flow with no apparent source?
Today we benefit from knowledge of the hydrologic cycle, and can now confirm that the source of water is not just a gift from the gods. This planet works in a logical progression, allowing us to understand how the earth and water cycles function. We can observe the slow, steady results of plate tectonics and sometimes witness their tragic outcome, as with the 2004 Indian Ocean underwater earthquake and tsunami.
We know that water becomes contaminated for specific reasons that are usually identifiable and correctable. If water has a foul taste or odor, it can be traced to a root cause and can then be treated for a particular use. From a chemical standpoint, water is an excellent solvent, dissolving a little of nearly everything it contacts. Water “contaminated” by calcium can be safely assumed to have passed through an area of rock containing this hardness mineral. Today, the water treatment industry is well equipped to tackle the wide range of aesthetic and potentially harmful water contaminants encountered throughout human populations.
In streams and rivers, clarity is better where the water runs fast, with people throughout the ages instinctively opting for the perceived purity of rapidly moving water rather than drawing from a stagnant pool. Actual water treatment methods may have started with simple settling followed by siphoning the cleaner water off the top. Boiling water for purification purposes appears to date back thousands of years. Straining water through various natural materials or cloth has long been a basic water treatment strategy. For centuries, sand filters both natural and man-made have been known for their water treatment capabilities.
These methods were often only partially effective and generally slow and inefficient. Larger human populations, along with poor water and wastewater management, led to increased instances of waterborne diseases, resulting in deaths that continue even today. The industrial revolution led to untold advances in technology and quality of life, but it also led to water pollution and related treatment challenges.
Water Purification Today
Today, we combine many of the old-school water purification methods with more scientifically advanced methods. Sand filtration can produce water at a highly efficient rate when we use long lasting, back washing filter media designed for specific purposes. Granular activated carbon (GAC) may be the hardest-working media ever. The pore structure and adsorption ability of GAC provides us with a multifunction filter that can treat a wide array of dissolved organics. Appropriately sized, especially for proper contact time, carbon can be your high capacity MVP when it comes to aesthetic water filtration.
We also go to battle with various chemicals that may be perceived as a panacea for many of our water treatment needs. Ion exchange resins are designed with an affinity for particular charged particles or contaminants that are removed at varying rates. In most cases, the ion exchange process is relatively fast, resulting in high volume and capacity capabilities. Ion exchange resins are typically regenerated on site so the filter can be used over and over again. But this is not without potential problems. Using chemicals or regenerants can lead to anticipated and, more disturbingly, unexpected consequences.
For example, chlorine may be one the most useful chemicals at our disposal, but improper use or dosing may have an impact far more problematic than the original treatment challenge. Great care must be taken in advance to account for the results of any proposed water treatment method to prevent an equally or more complex predicament.
When Potable is Not Good Enough
In residential water treatment, we are typically dealing with a potable influent water supply. As water professionals, we never confuse “potable” with “preferred.” End users are not satisfied with a level of water that merely meets minimum U.S. Environmental Protection Agency and/or state water quality standards. Simply being fit for human consumption is not what today’s homeowner is demanding.
Ion exchange water softeners are a tremendously versatile and simple type of water conditioner. Softeners are most commonly used for the removal of hardness minerals such as calcium, magnesium and low levels of iron. There are several minor operational parameters to consider with softeners, such as total dissolved solids interference, oxidants and flow rate limitations—both maximum and minimum. Portable exchange softeners have not faced the same level of scrutiny as automatic softeners, but don’t be surprised if they are next on the list.
The most pressing automatic softener issue of late has been residual chlorides, a byproduct of the regeneration process. An increasing affluent population exacerbates concerns about chlorides and the increased total dissolved solids in the waste stream of softeners. Barring the discovery of a new method of regeneration or a substitute softening technology, this issue will not simply fade away. As automatic softeners continue to suffer ever-increasing legislative attacks, the need for highly efficient systems and alternative technologies grows.
Many softener systems are now third-party certified to provide over 4,000 grains of hardness removal capacity per pound of salt. High efficiency ratings can significantly reduce the chlorides load and regenerant water required. This high efficiency and certification means nothing unless the system is properly sized, installed, set up and maintained.
There are many point-of-entry (POE) systems that deserve consideration as softener alternatives. Magnets and electronic devices have shown promise in limited applications, but have yet to gain widespread market approval. Multifunction POE systems containing polyphosphates and other mixed media offer a possible solution in limited applications.
Catalytic media relying on the removal of scale may provide yet another option to the softener dilemma. Most of these alternative technologies rely heavily on anecdotal evidence and testimonials. There is ample evidence that consumers, at least in limited numbers, have accepted these systems. As times get tougher for automatic softeners, these alternatives will become more attractive to the water conditioning dealer. The main complaint with these saltless water conditioners seems to be the lost silky feeling attained from using softened water. My experience has been that the level of satisfaction with the softener alternatives is far lower for those who are currently soft water users.
What We Can Do
Consumers new to the water conditioning market are more likely to embrace alternate technologies because the benefits can be significant and the maintenance demands tend to be reduced. Offering more than one type of POE water conditioning system makes sense in today’s volatile and competitive market. There is no one system that works best in every application, so diversify and provide the best system for each application.
Consumers appreciate honesty and like to have choices that take into consideration their needs, budgets and environmental concerns. Offering high-quality, custom-designed options is what can separate the water treatment professional from the big box retailers that sell low-cost “cookie cutter” appliances.