Water Desalination: Ways to Desalinate Water in an Emergency

glass of water

Ninety-seven percent of the water in the world is tied up in the ocean, the remaining 3 percent is found in groundwater, ice, lakes, and streams. When you look at the numbers, the ocean’s reserves can be the number one source of water when it comes to an emergency situation.But, ocean water is not good for people to drink. As the kidneys process salt they can only produce urine that is less salty than the water in the ocean. This means that to be able to get rid of the excess salt in your body you need to consume more water. As you drink water from the ocean you will feel dehydrated rather that rehydrated. It is a good idea to learn how to desalinate water in case your best water source in an emergency is the ocean.

Desalination process is a little bit different from purifying water and it requires more effort and equipment.

What is desalination and how does it work?

Desalination is the process wherein you’re going to remove the salt from ocean water in order to have fresh water. If you have successfully desalinated ocean water, you can now use it for drinking, for agricultural purposes, or for industrial purposes.

Desalinating ocean water is an inherently energy intensive process. There are a lot of reasons why water is expensive and one of them is the process of making ocean water into fresh water. Before the water from the ocean can be desalinated, it must be treated and/or filtered first. These processes also require equipment, facilities, and manpower.

Even though the cost is high, desalination is still considered as a useful process and a lot of areas are using this process. Wind and solar power can now be used for desalination.

Different Types of Desalination


Distillation is the process wherein you boil ocean water and collect the condensate. In this process the salt and other minerals will be left behind. There are various ways to distill water, depending on what materials or tools you have available. But you will basically need a heat source (campfire, alcohol stove, the sun, etc.), one container for the salt water and another for the condensate.

The following video is an example of a DIY water distiller.

Reverse osmosis  

Reverse osmosis is the process wherein you use pressure and a semi-permeable membrane. Osmosis is a naturally occurring process wherein a solvent which is the water and a solution which is the salt water equalize across a semi-permeable membrane. This happens as the solvent flows from less concentrated to more concentrated water until the process has achieved equilibrium.

Reverse osmosis is where the process is done the other way. This process will apply pressure to the water side pushing water molecules to the less concentrated side to produce salt-free water.

Different Methods of Desalinating Salt Water

Solar distillation

You can use this process however; production from a solar still is small. To make this process more efficient, you can invest in a solar oven.

You can make a solar still using a

Home distillation

It is possible to use this process, but it requires a lot of fuel, which can be a problem in an extended emergency situation where fuels may not last very long. You may use wood as fuel but collecting them can also require a lot of work and time.

Reverse osmosis

This process needs some investment and planning.

Buy A Desalinator

If you are living in an area wherein there is a source for salt water, buying desalinator can be a good option for you.

Here are some common types of desalinator:

  • Manual desalinator

An example of a manual desalinator is the Katadyn Survivor 06. This desalinator is used by pumping; it will give pressure to the water so that the water will be forced through the membrane. Using this desalinator requires a lot of energy because you need to pump it 40 times per minute in order to produce 0.89 liters of fresh water per hour. 2400 pumps is equivalent to less than one liter of water.

  • Powered desalinator

If you don’t want to use the manual desalinator, you can use the powered desalinator. This desalinator needs batteries or generator. Unlike the manual desalinator, powered desalinator can produce a large amount of fresh water, but you have to make sure that the batteries, solar panels, or generators can all function during an emergency situation. Powered desalinators are more expensive than the manual desalinator. An example of this desalinator is the Katadyn Power Survivor 40E that cost for about $4,000.00. This desalinator runs on 12 volts and can produce 1.5 gallons of water per hour.

Knowing how to desalinate water in an emergency situation is important. If you think you will definitely need a desalinator when SHTF, make sure to plan and be prepared. You have to learn the different techniques on how to desalinate water. You also need to know how to accomplish this task. You must remember that this process needs equipment, planning, and preparedness.

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