By J. Dallan Randall
Summary: In this age where so many of us seek “pure” water, distillation is often overlooked by more popular treatment technologies, namely RO. The author, who runs a distillation business, argues the case for distillers and dispels a few myths along the way.
We see it everywhere—“Use only distilled water” and “Recommended: Use distilled water.” On our clothes irons, car batteries, dental and medical equipment, and numerous other items we see these labels. But why distilled water? Is it because it’s the most commonly recognized, reliable and available of the demineralized waters? It might be argued that reverse osmosis (RO) water should be recommended—and, in some cases, it is. But let’s face facts, there’s no doubt that when an RO system is properly applied and maintained, it can be an excellent demineralizer; however, many of the under-the-counter systems people have in their homes miss out on the regular maintenance part. Distillation is more reliable. During the distillation process, water turns to vapor and 99 percent of inorganics are consistently left behind. The quality of water doesn’t fluctuate nearly as much as is the case with an RO system due to possible neglect in filter changes, membrane flaws or premature failure due to chlorine exposure.
After stating the above, the question can be asked, “Why aren’t there more distillers being sold for home use?” The remainder of this article will present several of the more popular reasons and concerns that have hindered people from buying distillers, and dealers from selling distillers, in the past.
Myth vs. fiction
It’s been predicted that distiller sales will increase in coming years as people’s concerns about taste turn to health with further emphasis on pure water. “Pure,” in this case, means distilled. It could be said that distillers are one of the few systems that can correctly be categorized under both disinfection and purification, unlike RO, which requires additional technology for disinfection. The distiller is the only standalone system that disinfects primarily by heat and removal rather than just killing and leaving the dead residue in the drinking water. This is enhanced by carbon filtration to avoid “carryover” of contaminant residue into the product water chamber. “Water distillers produce essentially mineral-free water… It both disinfects the water and removes most constituents, producing what is commonly accepted as ‘Safe and mineral free water.’”1 Total dissolved solids (TDS) and unwanted contaminants with higher boiling points than water don’t change to a vapor state. Ideally, they remain behind in the boiling chamber. The removal rates of inorganics and TDS can be expected to be 95-99 percent. The carbon filters bring removal rate of organics up to nearly 99 percent. During the boiling process, it’s possible for a drop of water to splash up into the condensing coil, which can account for 5 percent of the carryover. Still, distillation consistently removes contaminants. Its quality of water doesn’t degrade over time, and there’s no worrying about imperfections in the membrane.
Distillers & VOC removal
One of the more rampant myths includes VOC removal. Volatile organic compounds (VOC) can be summed up as chemicals that convert readily to gas. They may be carried over during the distillation process. It’s true that the process of distillation alone isn’t effective at reducing all VOCs; however, most modern distillers are equipped to be extremely effective at removing many VOCs. By pre-treating the water with an activated carbon filter, most if not all VOCs are removed before distillation. Once in the boiling chamber, many VOCs with a lower boiling temperature than water will vent through the volatile gas vent. A final polishing carbon filter ensures VOC removal. Manual units only contain a post-filter, but this has often proved sufficient.
To protect the consumer from unwanted VOCs, it’s vitally important to change filters according to manufac-turer’s guidelines. For example, Omni-pure’s six-inch filters are rated at 1,000 gallons or one year, whichever comes first. Some may look at the small filter and ponder how it can run for so long, but it’s important to realize that, because of its porous structure, a teaspoon of carbon can contain the surface area of a football field.2 Secondly, when the filters are rated, the recommended capacity can be as much as half that at which it was actually tested. The fastest home distiller has an output flow rate of 0.25 gallons per minute (gpm), well below the 0.50 gpm flow rate at which the filters are rated. Table 1 shows the test results of a distiller using pre- and post-carbon filtration and a volatile gas vent.
Steam as removal system
Some people may believe distillation removes beneficial minerals. I’m amazed at how often this question still arises. Let me pose this question to all water treatment professionals—What is an RO system supposed to do? Remove all the bad stuff and leave in the good? That’s ridiculous. All point-of-use (POU) systems out there today, whether it be an undersink RO, a faucet-mounted filter or a distiller, are all trying to do the exact same thing—remove everything from the water. Steam distillation does exactly that; it makes pure water.
In addition, it’s well known that the body gets the vast majority of essential minerals from the food we eat and one would have to drink thousands of glasses of water a day to get the same quantity from water. You’d essentially drown before being able to accomplish that.
Distillers aren’t convenient?
Nothing could be further from the truth. Portable countertop distillers may fit under this classification, but so do all portable POU systems. Distillers are actually preferred in high-end custom homes because they’re convenient and reliable and meet the needs of high-peak flow demands.
During the boiling process, a small amount of heat can be radiated so, in warmer climates like Arizona, machines are placed in the garage or utility room by the water heater; in colder climates, they may be located indoors. The water is pumped in through dedicated pure water lines to many locations in the house, but always to the kitchen sink and ice maker. Softened water and a properly adjusted auto dump are the keys to making the unit self-cleaning and maintenance free other than the annual filter changes. Distillers usually come with 10-, 25- or 80-gallon storage tanks so there’s always plenty of water for high-peak demands and the tank replenishes at eight or 12 gallons per day.
Distillers use lots of energy
Compared to what? Compared to an RO system that doesn’t use any, sure it’s extensive; compared to a water heater, it’s a drop in the bucket. Consumers heat hundreds of gallons every day5 so what’s another three to 10 gallons for pure drinking water? For you more technical gurus, it takes 3 kilowatts to distill one gallon of water.
Too hot for consumption?
It’s an easy misconception that, because distilled water is boiled, it’s too hot for immediate use. But for those who contend this, remember, it’s only the archaic distillers used in chemistry labs. In modern distillers, the steam is cooled to room temperature before being deposited in the storage tank. Those who like their water cold have more options than just adding ice; they can have the water pumped from the storage tank through a chiller to any location, or to their refrigerator with an in-the-door dispenser. So, they can have a cool glass of water available anytime.
A flat/bland taste?
This myth is due to preconceived notions that distilled water tastes bad. The root of this myth can be traced to two main sources. One, it started when old-fashioned distillers didn’t remove VOCs and thus gives the water an off taste. Two, distilled water is often mistakenly stored in cheap plastic containers that have been known to leach unwanted tastes and odors into the water. It’s also important to realize one can acquire and be accustomed to certain tastes. For example, someone used to drinking tap or well water will recognize a change in flavor when drinking purified water. Many consumers believe you need minerals in the water to make it taste good when it’s actually the dissolved oxygen in water that affects the taste, so try a glass of distilled water and enjoy the refreshing taste of pure water that thousands of people enjoy every day.
In homes and industry, nothing will ever take the place of pure water. This is all the more reason for it to be readily available to the consumer. Consumers have already proven this via the growth of this $4 billion industry; it’s the quality of water that counts, not the cost. Despite the myths of distillation, it continues to set the standard of purity in the water industry.
- Water Processing, Water Quality Association, Lisle, Ill., p. 213, 2000.
- “Fractal Carbon Nanopore Network,” Physics News Update, American Institute of Physics: www.aip.org/enews/physnews/2002/split/578-1.html
- Omnipure Filter Co., Caldwell, Idaho: www.omnipure.com
- “Water Filtration” Water Quality Association, Lisle, Ill., 1993.
- “Dollars Down the Drain: Saving Water, Energy and Money in the Home,” Iowa State University, Department of Agriculture & Biosystems Engineering: http://www.abe. iastate.edu/HTMDOCS/pm1089.pdf
About the author
J. Dallan Randall is manager of JB Sales Water Distillers, a nearly 20 year old company based in Mesa, Ariz. He oversees installation and service of Durastill distillers in Arizona including doctors offices, medical facilities and residences. He can be reached at (480) 969-3193 or (480) 969-3167 (fax).