How do water distillers purify your water?

Water distillers are not only one of the most effective water treatment systems available today, they are also one of the easiest to understand. With a water distiller, untreated water is converted into water vapor, which is then condensed back into liquid form. The majority of the contaminants present in the water are left behind in the boiling chamber, resulting in the condensed water being virtually contaminant-free. Anyone who has accidentally let a pot of water evaporate via boiling on the stove is familiar with this process, and the crust of contaminants typically left behind after the water is gone. In nature, this basic process is responsible for the hydrologic cycle. The sun causes water to evaporate from surface sources such as lakes, oceans and streams. The water vapor eventually comes into contact with cooler air, where it re-condenses to form dew or rain. This process can be imitated artificially, and more rapidly than in nature, using alternative sources of heating and cooling. How To Select A Distillation System With several different types of distillation systems available, the ideal way to choose an appropriate system is to determine the quantity of water required. Most households and businesses use inexpensive, yet effective, single-stage distillers that provide between one and 100 gallons per day (gpd) of treated water. More economically efficient commercial distillation units do exist – and can produce upwards of 5,000 gpd – but require significant amounts of heat and variations in steam pressure in order to convert the massive amounts of water into steam. Most distillation units use either electricity or, to a lesser extent, gas to generate the heat necessary for the conversion. While it is difficult and costly to get past the initial heating of the water, efficiency can be gained by reusing the heated steam to preheat incoming water. Household Distillation The most common type of household distillers available are basic, single-stage distillers. The majority of these distillers are relatively compact countertop or stand-alone units developed for use in the kitchen or office. Generally, they are either batch distillers, where a measured quantity of water is manually poured in, distilled and collected; or plumbed distillers, which automatically treat and maintain a constant pre-determined supply of drinking water. With a single-stage distiller, a heating source heats the water until it boils and eventually becomes steam. The steam is then drawn away from the boiling chamber and held until it cools, eventually condensing into highly treated distilled water. The contaminants in the original water are left behind in the boiling chamber. The condensing process is accomplished utilizing air or water to quickly cool the steam. With some system designs the steam passes through coiled tubing, which is either immersed in cool water or cooled by a fan. In others, the roof of the boiling chamber is cone-shaped, with the cone being cooled by the non-heated water stored above it. Water droplets condense on the inside of the cone-shaped dome and run down for collection in a drip pan. With some water-cooled systems, channeling the heated cooling water back into the boiling chamber can reclaim a portion of the heat lost as the steam is cooled and condensed. It is then replaced with fresh, cool water. This pre-heated water requires less new energy to convert it into steam. While the distillation process alone is very effective in ridding water of pollutants, certain pesticides and contaminants like volatile organic compounds (VOC's) and radon convert into vapor readily and can travel with the steam out of the boiling chamber. Accordingly, almost all household distillers use special vents and carbon pre- and post-filters to effectively deal with these contaminants. Distillation units do require some maintenance, which usually involves draining off the concentrated sediment and other contaminants that accumulate at the bottom of the boiling chamber. The walls of the chamber may also need to be cleaned of hard-water scale and other sediment build-up. The amount of cleaning required depends greatly upon the initial quality of water used. While very hard water can produce heavy scaling in a relatively short period of time, soft water leaves behind little scaling and makes cleaning frequencies and difficulties minimal. Any carbon pre- and post-filters must also be changed periodically. Typical household distillers cost between $300 and $1,000 and produce water for as low as $.25 a gallon, energy and filter costs included. Commercial Distillation Many commercial operations use multiple-effect distillers that produce anywhere from 75 gallons to millions of gallons of water per day. These units typically contain a number of boiling chambers, with the first chamber operating under increased pressure and the successive chambers having progressively decreasing pressure. The units are designed this way to take advantage of the fact that the greater the steam pressure, the higher the boiling point and temperature of the steam produced. The steam created in the first high-pressure chamber is ''superheated'' to a point well above the temperature needed to create steam in the lower-pressure chambers. As this superheated steam moves through tubes surrounding each of the succeeding boiling chambers, it ''flash'' vaporizes some of the cooler, lower-pressure water in each chamber. The flash vapor is then condensed into distilled water, as is the superheated steam when all of its heat energy is exchanged. The self-sustaining nature of this process can be quite efficient for large quantities of water, since the only energy source required is either an electric or gas heating element for the first boiling chamber. A variation of this multiple-effect distiller concept is the vapor-compression distiller, which is typically used in commercial applications requiring between 25 and 5,000 gpd. Vapor-compression water distillers also use high-pressure, superheated steam to boil water; however, they only use a single chamber. The water in the boiling chamber is initially converted to steam at normal pressures and temperatures by an electric or gas heating element. The steam then passes through an electric compressor, where the compression causes it to become superheated. The superheated steam is then directed through tubes back into the boiling chamber, where it eventually takes over the boiling process, condensing into distilled water as the heat transfer occurs. These systems are typically more efficient than multi-effect units, since the energy required to operate the compressor is less than that required to heat water using a heating element. The greater efficiency usually brings with it a greater cost, as compared to multi-effect units. Both multi-effect and vapor-compression distillers can incorporate various forms of filtration to make a broadly effective treatment system. These systems can provide water for such uses as commercial water bottling. Both systems also require water that is softened to a practical level, in order to prevent debilitating scaling that result in heat transfer losses and maintenance costs. At the municipal level, both multi-effect and vapor-compression distillation can provide large quantities of distilled water for drinking use, and are especially useful in distilling seawater for use in arid areas adjacent to the oceans. What Water Distiller Units Treat Distillation is an effective process for purifying water by significantly reducing amounts of sediment, metals and biological contaminants, which are unable to travel out of the boiling chamber with the steam. When combined with an effective carbon water filter, contaminants like VOC's and radon can also be controlled. It is recommended that only units designed and tested for health-contaminant reduction be used for such purposes. These units, when used with a carbon water filter, can be used to effectively treat such contaminants as: · Arsenic · Asbestos · Atrazine (Herbicide/pesticides) · Benzene · Fluoride · Lead · Mercury · Nitrate · Trichloroethylene (TCE) · Trihalomethanes · Radium · Radon · Biological contaminants (bacteria, viruses, and water-borne cysts like cryptosporidium) A distillation system with a carbon water filter can also be quite effective for treating aesthetic drinking water contaminants like chlorine or iron bacteria, which lead to unpleasant tastes, odors and colors. Distillation is an effective water treatment technology for household and commercial use. It provides water with a distinct clarity, ridding the liquid of up to 98 percent of its impurities. Distillation units are continually being improved to increase efficiency and water output, making them an increasingly popular and cost-effective option for residential and commercial users alike looking for an effective way to filter water. Home Page | FAQs | Glossary | Contact Us