What is Water Distillation?

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Brian Campbell is the founder of WaterFilterGuru.com, where he blogs about all things water quality. His passion for helping people get access to clean, safe water flows through the expert industry coverage he provides. Follow him on twitter @WF_Guru or contact him by email [email protected].

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 water treatment method for removing contaminants like 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 steam is then captured and condensed into a clean container. 

The majority of inorganic compounds and non-volatile molecules are unable to evaporate with water, and end up left behind in the boiling chamber. 

Small-scale distillation units look a little like coffee pots. They consist of a boiling chamber, condensing chamber (or coils), and a storage container for the clean water. 

The distillation process is as follows: 

1. Water is heated in a boiling chamber. The water is heated to a rolling boil, which causes evaporation and steam production.
2. Steam leaves the boiling chamber. The steam from the boiling water rises through a vent into a stainless steel condenser. Any microorganisms, impurities and contaminants that are unable to convert into gas particles are left behind in the boiling chamber.
3. Steam condenses. Once steam reaches the condenser, it is chilled by a fan until it turns back into water droplets. These droplets are now ready to be collected in a clean container - but there is one final filtration stage first. 
4. Remaining contaminants are removed. Any 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.
5. Water collects in a storage container. After passing through the filtration media, water will drip out of the distiller’s spout and into a holding container. This water is now clean, pure, and ready for use.

Distillation can remove a broad range of contaminants from water, including nitrate, iron, lead, hardness, and some microorganisms. 

The overall effectiveness of distillation depends on the contaminants the water contains. For instance, some organic compounds, like benzene, have lower boiling points than water. 

This means that these contaminants will end up re-contaminating water once it has condensed into liquid form. Most distillers use a filter media, typically activated carbon, to trap any lingering contaminants before water can leave the machine. 

How Long Does Water Distillation Take

Water distillation is not a fast process. The average countertop water distiller takes between 4 and 6 hours to produce a single gallon of purified water. Water is produced one droplet at a time. 

This process can be accelerated using a larger distiller, which may be able to produce up to three gallons of water per hour, depending on the system. However, there is no speeding up the distillation process. For anyone looking to produce large batches of distilled water, the better 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. 

Distiller plants are a lot more capable than single-use countertop distillers. Depending on the number of units used, distillation plants may be able to 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, cosmetic manufacturers, and automotive businesses. Distilled water may 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 in day-to-day operation. 

What Are the Benefits of Distilled Water?

Bacteria and Virus-Free

Distillation removes bacteria, viruses and other microorganisms from water. Whether distilled water is being used for food, beauty or drinking purposes, being free of potentially harmful microorganisms is a big selling point. 

Purest Water Option

Not many methods of water filtration are as effective as distillation. A distiller can produce water that is almost 100% pure. Other types of water treatment, on the other hand, may only be designed to target specific contaminants. 

Numerous Household Uses

Distilled water has numerous uses in the home. It can be added to steam irons to avoid 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 if they bought bottled water for drinking. However, because distillers remove healthy minerals and vitamins from water, many people would argue that bottled mineral water still tastes nicer. 

Industrial & Commercial Benefits

Distilled water is not only beneficial for the homeowner. It can also be used in cosmetics manufacturing, laboratory experiments, canned goods production, and for automotive purposes. Distilled water may also be used to sterilize medical equipment and surfaces. 

What Does Water Distillation Remove from Water?

Distillation removes a broad range of inorganic compounds from water, including metals like lead, iron, hardness minerals, nitrates, sodium, and most other dissolved materials. The boiling and evaporation process is also effective in killing viruses, bacteria, and other microorganisms. 

While distillation is a highly effective form of water treatment, its  worth being aware that it may not remove all contaminants from a water source. 

Distillation is not a fail-safe treatment option for removing some types of semi-volatile and volatile organic compounds (or VOCs for short). 

Certain organic compounds, like most pesticides, have higher boiling points than water. This means that they can be removed during distillation. However, some organic compounds have lower boiling points than water, meaning that they, too, will evaporate during the boiling process, and will condense with water into the container. 

These compounds should be removed either during or prior to 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 needed) to remove these difficult contaminants.