Brian Campbell is the founder of WaterFilterGuru.com, where he blogs about all things water quality. His passion for helping people gain access to clean, safe water runs through the industry expert coverage he provides. Follow him on twitter @WF_Guru or contact him by email brian.campbell@waterfilterguru.com.
What is Water Distillation?
Water distillation is a process in which water is boiled until it evaporates and condenses, leaving behind impurities with different boiling points.
Distillation produces clean, pure water. It is an effective method of water treatment to remove contaminants such as bacteria, heavy metals and chemicals.
How does water distillation work?
During distillation, water is boiled in a boiling chamber until it evaporates into steam. This vapor is then captured and condensed in a clean container.
The majority of inorganic compounds and non-volatile molecules cannot evaporate with the water and end up staying in the boiling chamber.
Small-scale distillation units look a bit like coffee makers. They consist of a boiling chamber, a condensation chamber (or coils) and a storage tank for clean water.
The distillation process is as follows:
- Water is heated in a boiling chamber. The water is brought to a boil, which causes evaporation and the production of steam.
- Steam leaves the boiling chamber. Steam from the boiling water rises through a vent into a stainless steel condenser. All microorganisms, impurities and contaminants unable to convert into gas particles are left in the boiling chamber.
- The steam condenses. Once the vapor reaches the condenser, it is cooled by a fan until it becomes water droplets again. These droplets are now ready to be collected in a clean container – but first there is a final filtration step.
- The remaining contaminants are removed. All impurities that have evaporated and condensed with water can now be removed. Usually an activated carbon filter will trap these contaminants using the process of adsorption.
- Water collects in a storage container. After passing through the filter media, the water will drip out of the still spout and into a holding vessel. This water is now clean, pure and ready to use.
Distillation can remove a wide range of contaminants from water, including nitrate, iron, lead, hardness, and some microorganisms.
The overall efficiency of distillation depends on the contaminants in the water. For example, some organic compounds, such as benzene, have lower boiling points than water.
This means that these contaminants will eventually re-contaminate the water once it condenses back into liquid form. Most distillers use filter media, usually activated carbon, to trap any lingering contaminants before the water can leave the machine.
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How long does water distillation take
Water distillation is not a quick process. The average countertop water distiller takes between 4 and 6 hours to produce a single gallon of purified water. Water is produced one drop at a time.
This process can be sped up by using a larger still, which can produce up to three gallons of water per hour, depending on the system. However, there is no acceleration of the distillation process. For those looking to produce large quantities of distilled water, the best alternative would be to use a water distillation plant.
RELATED: What is zero liquid discharge (ZLD)?
What is a Water Distillation Plant?
A water distillation plant is a large-scale distillation solution that can be used for commercial or manufacturing purposes.
Distillation plants are much more efficient than single-use countertop distillers. Depending on the number of units used, distillation plants can produce up to hundreds of liters of purified water per hour.
There are a number of industries that may require large scale production of distilled water. These include laboratories, cosmetics manufacturers and automotive companies. Distilled water can also be used in canning produce and brewing beer. Some bottled water manufacturers produce and sell distilled water.
A distillation plant offers a higher level of performance, which is essential for industries that require large quantities of distilled water on a daily basis.
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What are the benefits of distilled water?
Without bacteria or viruses
Distillation removes bacteria, viruses and other microorganisms from the water. Whether distilled water is used for food, beauty or beverage purposes, the absence of potentially harmful microorganisms is a strong selling point.
Purest water option
Few water filtration methods are as effective as distillation. A distiller can produce almost 100% pure water. Other types of water treatment, on the other hand, can only be designed to target specific contaminants.
Many home uses
Distilled water has many uses around the home. It can be added to steam irons to prevent limescale buildup and used in aquariums and car cooling systems. Distilled water can also be used for watering plants.
Cheaper than bottled water
People who make their own distilled water at home can enjoy pure, clean water for a much lower monthly cost than buying bottled water to drink. However, because distillers remove healthy minerals and vitamins from water, many people would say that bottled mineral water always tastes better.
Industrial and commercial advantages
Distilled water is not only beneficial for the owner. It can also be used in the manufacture of cosmetics, laboratory experiments, canned food production and for automotive purposes. Distilled water can also be used to sterilize medical equipment and surfaces.
What does water distillation remove from water?
Distillation removes a wide range of inorganic compounds from water, including metals like lead, iron, hardness minerals, nitrates, sodium, and most other dissolved matter. The boiling and evaporation process is also effective in killing viruses, bacteria and other microorganisms.
Although distillation is a very effective form of water treatment, it should be noted that it may not remove all contaminants from a water source.
Distillation is not a foolproof treatment option for removing certain types of semi-volatile and volatile organic compounds (or VOCs for short).
Some organic compounds, like most pesticides, have higher boiling points than water. This means they can be removed during distillation. However, some organic compounds have lower boiling points than water, which means that they too evaporate during the boiling process and condense with the water in the container.
These compounds must be removed during or before the condensation process to prevent them from contaminating the finished product. Testing a water source for contamination in advance can ensure that the right processes are used alongside distillation (if necessary) to remove these difficult contaminants.
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