Distillation Can Remove Contaminates from Drinking Water

With increasing concerns about contaminants in water that may affect health, distillation can remove contaminates from drinking water.

Distillation is an effective method for removing most contaminates

According to the U.S. Environmental Protection Agency: “Distillation is an effective water treatment technology for commercial and household use. When water is purified by distillation, it is boiled in a container and the steam is sent into cooling tubes. The steam is condensed and then collected as purified water in a second container. The impurities in the water are left behind in the first container and can be discarded. The distillation process removes almost all impurities from water. Distillers are commonly used for removing nitrates, bacteria, sodium, hardness, dissolved solids, most organic compounds, and lead. Contaminants that easily turn into gases, such as gasoline components or radon, may remain in the water unless the system is specifically designed to remove them. Distilled water may taste flat to some people because the water’s natural minerals and dissolved oxygen often have been removed.”

Contaminants Removed from Water by Distillation

Distillation can remove most impurities from water. Compounds removed include sodium, hardness compounds such as calcium and magnesium, other dissolved solids including iron and manganese, fluoride, and nitrate. Distillation effectively inactivates microorganisms such as bacteria, viruses, and protozoan cysts. Distillation can also remove many organic compounds and heavy metals.

Contaminants Not Removed from Water by Distillation

Depending on the contaminates, a combination of treatment processes may be required to effectively treat the water. Certain pesticides, volatile solvents, and volatile organic compounds with boiling points close to or below that of water will vaporize along with the water as it is boiled in the distiller. These compounds will not be completely removed unless another process is used prior to condensation.

Treatment Principles

Distillers use heat to boil contaminated water and produce steam. Impurities such as inorganic compounds and large non-volatile organic compounds are not vaporized and are left behind in the boiling chamber. The heat inactivates bacteria, viruses, and protozoan cysts. The steam rises and enters a cooling section. When the steam cools, it condenses back to a liquid. The resulting water can have up to 99.5 percent of impurities removed. The water remaining in the boiling chamber has a much higher concentration of impurities and should be discarded.

Since volatile organic compounds can also vaporize­ as the water is boiled and turned to steam, methods for removing them can be incorporated into the system. Distillers that use a combination of removal methods are more efficient than those with a single method. section

Remove Contaminates using Distillation
Diagram courtesy of North Dakota State University Extension Service

Incorporating gas vents (small holes in the passage leading to the condensing coils) can allow volatile organic compounds to escape before entering the cooling section.

Another option is to use an activated carbon filter to remove volatile organic compounds from the condensed water before they enter the storage tank.

 

In and emergency, a simple distiller can be made using a pot and stove or a pot and solar energy. See “Distill Water Using a Pot and Stove” and “Solar Desalination for Drinking Water.”

In summary, distillation can remove contaminates from drinking water and is an effective solution in emergency situations.

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Distill Water Using a Pot and Stove

How to Distill Water Using a Pot and Stove

Distilled Water is water that has had many of its impurities removed through the process of boiling the water and collecting the resulting steam. In an emergency, the following is a simple method to obtain drinking water from contaminated water is to distill water using a pot and stove follows:

Get a large pot with a lid and an empty drinking cup. 

  • The glass should be big enough to hold a fair amount of fresh water.
  • Make sure the glass is short enough that you can still put the lid on the pot.
  • A Pyrex or metal cup is safest, as certain types of glass will explode when exposed to heat. Plastic may melt or deform.
  • Make sure the pot and lid are suitable for using on a stove.

Slowly pour the contaminated water into the pot. 

  • Do not overfill. Stop well before the water level has reached the mouth of the glass.
  • Make sure no contaminated water splashes into the glass while boiling. You don’t want to get any contaminated water into the drinking glass, or your newly made distilled water will be contaminated.

Place the pot, cover upside down on the pot. 

  • Position the pot lid so the highest point or handle is facing down directly above the glass. This will allow the water vapor to drip into the drinking glass as it condenses.
  • Make sure the pot lid is providing a good seal along the edges of the pot. Without a good seal, a lot of the steam will escape and diminish the supply of fresh water vapor.

Bring the water to a slow boil over low heat. 

  • Make sure you bring the water to a boil slowly over low heat. A violent full boil can contaminate the drinking water by splashing into the glass.
  • Too much heat can cause a glass to break.
  • If the water is boiling quickly and violently, the glass may shift away from the center of the pot and the handle of the pot lid.

Watch the pot as the water condenses. 

  • When water boils, it becomes pure vapour, leaving behind anything that was dissolved in it.
  • As the water becomes vapor, it condenses in the air as steam and then on the cover’s bottom surface as water droplets.
  • The droplets then run down to the lowest point (the handle) and drip right into the glass.
  • This will probably take 20 minutes or more.

Wait a little while before drinking the water. 

  • The glass and water will be very hot.
  • There may be a small amount of contaminated water left in the pot, so be careful when removing the glass of distilled water not to splash any contaminated water into your fresh water.
  • You might find that the glass and fresh water will cool faster if you remove it from the pot.
  • Be careful as you remove the glass so you don’t get burnt. Use an oven mitt or potholder to take it out.

In an emergency, a simple, effective method to obtain drinking water from contaminated water is to distill water using a pot and stove.

 

Source: http://www.wikihow.com/Turn-Salt-Water-Into-Drinking-Water

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Solar Desalination for Drinking Water

In an emergency, solar desalination is an effective way to obtain drinking water from salt water.

Solar Desalination Process:

1. Collect salt water in a bowl or container. 

  • Make sure you don’t fill it up all the way.
  • You will need some space at the top of the bowl so that the salt water doesn’t splash into your fresh water receptacle.
  • Make sure your bowl or container is watertight. If it is leaking, your salt water will drain away before it can form steam to condense as fresh water.
  • Make sure you have plenty of sunlight as this method takes several hours.

2. Place a cup or smaller container in the center. 

  • Do this slowly, If you do this quickly, you might get some salt water splash into your cup. This will contaminate your fresh water as you collect it.
  • Make sure the lip of the glass remains above water.
  • You might need to weight it down with a rock to prevent it from sliding around.

3. Cover the bowl with plastic wrap. 

  • Make sure the wrap isn’t too loose or too tight. 
  • Be sure that the plastic wrap has a tight seal on the rim of the salt water bowl.
  • If there are any leaks in the plastic wrap, steam or fresh water vapor might escape.
  • Use a sturdy brand of plastic wrap so it doesn’t tear.

4. Place a rock or weight in the center of the plastic wrap. 

  • Do this just above the cup or container in the centre of the bowl. 
  • This will cause the plastic wrap to dip in the centre, allowing fresh water to drip into your cup.
  • Make sure your rock or weight isn’t too heavy or it will tear the plastic wrap.
  • Make sure the cup is in the centre of the bowl before continuing.

5. Place the salt water bowl in directly sunlight. 

  • This will heat the water and cause condensation to form on the plastic wrap.
  • As condensation forms, fresh water droplets will drip from the plastic wrap into the cup.
  • This will allow you to slowly collect fresh water.
  • This method takes several hours so be patient.

After you have enough fresh water in your cup, you can drink it. It is safe and completely desalinated. Solar desalination is an effective way to obtain drinking water from salt water.

Source: http://www.wikihow.com/Turn-Salt-Water-Into-Drinking-Water

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