Water Purification Methods

Methods Commonly Used to “Clean” Water

There are many methods used to purify water. Below is a quick overview of some of the more commonly used methods.

Chemical

This is the method used by most municipal water systems, most of which use chlorine. Although chlorine is widely used in municipal water systems, there has been increasing concern that it may, in certain instances, be carcinogenic and contribute to heart disease.

Deionization

Often used after the RO process as a way to “polish” the water by removing any residual ions (salts) from the water. Water is passed through a bed of bead-like spherical resin materials and the ions attach to the resin and are removed from the water. This method is not effective at removing many common contaminants or bacteria and viruses, and is seldom used alone as the only water purification method.

Distillation*

By far the most effective way to produce the highest level of consistently pure water. Distillation is considered the method of water purification that most closely replicates the way Mother Nature purifies water. In nature, water on the ground evaporates, leaving behind any pollutants it may contain, and rises into the atmosphere where it is cooled and returns to earth in the form of rain. Before our atmosphere was polluted with sulfuric and nitric acid (acid rain), this natural cycle (called the Hydrologic Cycle) resulted in pure, clean water.

Distillation follows this same natural process (without the air pollution part!). In distillation, water is boiled until it becomes steam. Any contaminants in the water are left behind when this occurs. The steam is then cooled and condenses back into water – water that has left behind all the pollutants it contained at the beginning of the process.

Distillation removes bacteria, viruses, protozoa, fluoride, sodium, nitrates, asbestos, all minerals including heavy minerals, and much more. Distilled water is so pure that it is used in numerous scientific processes that require the purest water and in sensitive patient populations such as patients on dialysis for kidney disease.

Distilled water has no taste or odor because it is devoid of those things in our water that create taste, such as chemicals and impurities. Distilled water should ideally be kept in glass or high-quality plastic containers. If distilled water is stored in HDPE plastic bottles (#2 on the bottom of the bottle) it will begin to taste like the plastic!

Filtration

Water is pumped or passed through a filter or multiple filters. Filters may be made from a number of substances such as sand, diatomaceous earth, paper or cloth, porous stone or ceramics. Carbon filters are the most commonly used because they are inexpensive and will remove most chemicals, lead and bacteria. However, they are not effective against viruses. Filters must be replaced regularly to remain effective and prevent bacterial growth on the filter.

Reverse Osmosis*

Reverse osmosis, or RO, is an inexpensive way to remove >90% of contaminants. RO membranes contain pores that are much smaller than standard filters and will eliminate most impurities from water, including bacteria and viruses. In contrast to filtration, which essentially strains the water, RO uses hydraulic pressure and semipermeable membranes, to separate pure water from waste. Household drinking water purification systems often use RO. However, regular maintenance of these systems is required. If they are neglected, they can quickly become ineffective and even detrimental to water purity (bacteria will grow on the filters if they are not changed regularly).

Commercial RO systems are often combined with several other water treatment processes such as carbon filters to remove chlorine from the feed water, particulate filters to remove sediment or silt in the feed water, and water softening to remove minerals from the feed water. Additionally, commercial RO systems may also use downstream systems such as ultraviolet lights, ozone, and deionization to remove any residual ionic, organic or microbial contamination in the water.

The biggest drawback to the RO process is maintaining the consistency of water purification, as the effectiveness of the system requires meticulous attention to filter and membrane performance and frequent changing of filters and membranes to maintain water quality.

Ultraviolet light and ozone*

Exposing water to ultraviolet (UV) light and/or ozone is often used to kill any bacterial, viruses, or protozoa. UV lights produce short wave beams of light that are lethal to bacteria, viruses and other microorganisms. Ozone is a natural substance that is produced by plants and whenever lightening strikes the earth. The ozone layer is what protects us from harmful radiation from the sun. Ozone is also one of the most powerful natural germicides.

For water purification, an ozone generator is used to produce ozone that the water is then briefly exposed to – killing any bacteria, viruses or microorganisms in the water. Ozone is very unstable, and only exists for a matter of minutes before it reverts back to regular oxygen. Ozone is an expensive way to purify water and is therefore not feasible for large applications (such as municipal water systems) and is seldom used in household applications for this reason.

Our mission at Sedona Water Works is to offer our customers a selection of pure waters to choose from, available at a fair price, and combined with exceptional customer service.