Water extraction

How much water do we have in the first place?

I’m lucky to live in a quaint little neighbourhood called Canada. Canada has more lakes than all of the other countries of the world combined and hosts about 7% of all the freshwater available on earth. The city I live in also happens to rain a lot, so I have never been concerned about water. I know that is not many peoples reality.

The fact is, there is a crazy amount of water on earth. But as we all know, only a tiny portion of that is accessible and clean drinking water for humans. About 4% of the earths water is fresh/drinkable, but most of that is locked up in glaciers, or underground. The estimate I typically see is that 0.4% of the earths water is accessible to humans.

There are some creative ways we have learned to extract water from our environments when in need. I have been looking up some of them lately and wanted to share.

Water Stills

Let’s say you are stranded on a tropical island. The days are hot and sunny, which causes you to sweat and lose a lot of water every day. You are surrounded by the ocean, so there is plenty of water, you just can’t drink it. How do you take advantage of all the water around you and make it safe to drink?

You need to distill it. Distillation is the process of purifying a liquid using evaporation and condensation. The process of distilling ocean water consists of evaporating the water which separates the water from the salt by turning it into a gas. Then you let the gas rise and condensate on a cooler surface, which you then collect.

With distillation, you can actually extract water from almost anything. Leaves, urine, mud, and blood are all examples of things that can have drinkable water extracted.

Here is a diagram of what a solar water still would look like.

First you dig a hole. If you are on a beach, chances are, there will already be moisture accumulating at the bottom of the hole. That’s great. Throw some leaves in for good measure. Heck, urinate in the hole to if you’ve got to go. Grab a bucket and scoop some ocean water into the hole as well. Clean the bucket, then store it in the middle of the hole. Then lay a tarp or some material over the hole and pin it down on the sides. Then put a weight in the middle of it. You want the material to angle towards your bucket. This way, when the water in the hole evaporates from the heat of the sun, it rises and condensates on the tarp. Gravity will pull the water droplets towards the middle, where it will drip into your bucket. The water dripping in your bucket will be fresh water. Most people recommend putting some tubing into the bucket and stringing it out of the hole like a straw so you can drink without disrupting your creation.

A faster way to do this is to have a fire going which will create steam instead of waiting for the sun to evaporate the water.

Solar Domes.

Countries like Saudi Arabia exist in a desert, and are notoriously short on water, at least water that is obvious to see. They get a portion of their water from groundwater sources, but the remaining is extracted using water desalination plants.

Water desalination plants are set up near oceans and basically suck in ocean water and remove the salt, creating drinkable water. The first problem with water desalination plants is that they are very energy intensive. Saudi Arabia being rich in oil, uses a lot of fossil fuels to run their desalination plants. The other problem with desalination plants is the byproduct of the desalinated water is a thick salty brine. The brine is pumped back into the ocean which tends to destroy marine ecosystems in the area.

The country has been exploring more ecologically friendly ways to provide their citizens with fresh water.

One cool idea that is being worked on now uses similar principles as the water still I described above. It’s called a solar dome.

The process would go something like this:

First you have piping from the ocean to somewhere in the desert where the solar dome will be created. As the water travels through the pipe to the dome, the sun would heat it up on the way. The giant dome collects the warmed water.

The dome will be surrounded by hundreds of mirrors which can be angled to reflect and focus the suns rays on the dome. I believe I read that these mirrors when angled correctly can superheat the water to over 3000 degrees within a matter of seconds. Then, just like the solar stills, water evaporates, condensates and is collected in basins to be piped back to citizens.

This comes at a much lower cost than the desalination plants. The dome also apparently has ways to deal with the salty brine, including refining it for additional use such as lithium batteries.