Water Journey – Other Sources of Water

Only 3% of the Earth’s water is fresh water and most of that is in glaciers and ice sheets. So there’s not a huge amount of water to meet our growing everyday needs. Scientists and engineers are therefore looking at new and different ways to collect every drop that falls from the sky and also create fresh water from our oceans.

Hi. I’m Arno. I’m with the Aquanauts.

We’re wild about water and how to make sure there’s enough for everyone who needs it now and in years to come.

Here at Aquanaut HQ, we’re diving into desalination!

As you know, we all need water and lots of it! So where might we get more? Well, there’s one source that comes to us even when we’d rather it didn’t!

An easy way to create more water to use where we live, study and work is called rainwater harvesting.  After all, it rains on average around 160 days every year in the UK! 

Rainwater harvesting ranges from using simple barrels in our gardens to more elaborate designs with tanks, purification systems and pumps. It can be a cost-effective way to help reduce water scarcity.

Obviously, as rain water isn’t purified, we shouldn’t use it to drink or cook food, but it’s ace for watering the garden, washing things like our bikes and clothes, and even flushing the loo! Harvesting rainwater is also great at helping stop surface water collecting. It can also help reduce the risk of flooding by limiting water in our sewer systems.

As well as rain water, where else might we find alternative sources of water? 

Around half of our drinking water comes from ground water, that’s water held underground in the soil or in pores in rock, but there’s another massive source of water which you might think is a much more obvious source…

That’s our seas and oceans! After all, they cover 70% of the Earth’s surface, which is great news. However… and it’s a big BUT, all the water they contain is way too salty! Whilst a little salt is yummy on food, if you’ve ever swallowed sea water by mistake, you’ll know how horrible it tastes! So, with so much saltwater around, is there anything we can do? The good news is we can take the salt out and turn sea water into safe fresh water. This is known as desalination.

Aquafact – Desalination isn’t a modern concept. Way back in Ancient Greece, Aristotle observed that evaporated seawater would turn into fresh water. For many years sailors used basic desalination to obtain fresh water… simply by boiling seawater and condensing the steam. 

Now, whilst there’s a BUNCH of ways to desalinate seawater, the two primary methods are distillation where seawater is evaporated using the sun’s heat and the condensation is collected as fresh water. There’s also a clever process called reverse osmosis which forces seawater through very fine membranes, incredibly thin sheets, that catch the larger salt molecules but lets smaller water ones through.

The Thames Gateway Water Treatment Works, not far from where the River Thames meets the sea, is a desalination plant. 

• Like the majority of desalination plants, they use reverse osmosis. Although quite complicated, it’s currently the most widely used method as it’s efficient and uses less energy. 
• At Thames Gateway, 85% of the water they take from the Thames is turned into drinking water.
• Before it arrives at our taps, it’s purified to make it safe to drink and minerals are added to enhance its taste.  

Aquafact – Thames Gateway can supply 150 million litres of water per day. That’s enough to meet the needs of one million people.

So, why do we bother trying to collect rainwater and recycle used water if we can just get it from the sea?

Well, desalination is great because there’s loads of sea water around and it can be crucial in arid areas where freshwater resources are scarce, like the Middle East.

It’s also useful when you need to provide clean drinking water in areas affected by natural disasters and where conventional water supply systems are damaged or contaminated.

However, the process of desalination and purification can be expensive and uses a lot of energy. It also creates wastewater that contains high levels of salt and pollutants that needs to be disposed of safely so it doesn’t hurt marine life and that means more cost.

The good news is that desalination can be more effective and sustainable with new technologies like better membranes to capture bacteria and renewable energy.

It’s certainly a key way to help people across the world get their water. There’s currently over 16,000 desalination plants across the world. The first big adopter was Australia, whilst other big users are Saudi Arabia and the United Arab Emirates, both of which are desert countries and highly dependent on this process. Spain is also a big user.

It’s great that we can turn salty water into drinking water but we must still be careful not to waste it. You can help by becoming an Aquanaut and doing some simple things, like having a quick shower instead of a bath.

You can also explore a career in water engineering and technology. 

Water Workers

There’s a wide range of jobs across the water sector and today’s water worker is Chemical Engineers!

Chemical engineers develop and design chemical manufacturing processes. Chemical engineers apply the principles of chemistry, physics, and engineering to design equipment and processes for manufacturing products such as gasoline, detergents, and paper.

As well as being key in desalination, purifying water and cleaning up waste water needs a knowledge of the materials in it and their chemical composition, and how they react with each other and the environment. Chemical Engineers use their knowledge to design efficient and safe filtration systems and processes.

Take the challenge!

The Rainfall Water Symphony is a super creative activity that combines music and learning about the importance of rainwater. Ready? Download here!

Want to know more?

‘This is Engineering’ is an initiative led by the Royal Academy of Engineering in partnership with EngineeringUK and major engineering organisations to encourage young people from all backgrounds to consider a career in engineering. Click HERE to find out more… or perhaps visit the Museum of Engineering Innovation.

Stick with us… we’re gonna be helping you understand the challenges ahead, and discover some of the cool engineering and careers that are helping solve the issues. We’re also going to find out how we can all make a difference with more tips on how you can become an Aquanaut and help engineer our water future!

AQUANAUTS! CREATED WITH SUPPORT FROM A ROYAL ACADEMY OF ENGINEERING INGENIOUS GRANT AND CARDIFF UNIVERSITY.