Today’s Wonder of the Day was inspired by Henrik. Henrik Wonders, “How does a water purification plant work?” Thanks for WONDERing with us, Henrik!

What one thing could you never live without? Your favorite video game? Maybe a book you like or your favorite food? Sure, life would be a lot less enjoyable without those things. But people could certainly live without them, as long as their basic needs are met. 

Basic needs are things that people can’t live without. They include items—such as oxygen, food, sleep, and shelter—that are required for survival. Of course, there’s one more basic need we could add to that list. Can you think of what it is? We’ll give you a hint: it’s colorless, odorless, and covers about 70 percent of the Earth. What are we talking about? Water, of course!

There’s nothing like a big gulp of water to quench your thirst. Where does the water you drink come from? Is it bottled? Do you pour it from a filtered pitcher? Drink it straight from the tap? Water has a long trip to make before it gets to you through any of these sources. Before it’s considered clean enough for people to drink, water has to be purified.

Most likely, the water you drink starts in a nearby body of water, like a river or lake. And if you’ve ever seen a natural body of water up close, you know you wouldn’t want to drink water straight from the source. It contains natural contaminants, like dirt and debris. It’s also often full of pollution put there by people.

How do treatment facilities clean water? They start by removing the larger debris. Then, they add chemicals that cause small particles in the water to clump together. As the water sits, these clumps come together and fall to the bottom. This makes it possible for these contaminants to be filtered out of the water. 

After filtering, facilities add chemicals to the water that disinfect it. Most often, they use chlorine. Sometimes, they might use other methods of disinfection due to concerns about chlorine as a toxic chemical. The water is then exposed to air to remove dissolved gases from it. 

That’s how water purification works on a large scale. But how about those water filters you may have seen in water pitchers and bottles? They work a little differently. In a filter, water has to pass through a very small space made of either a membrane or carbon particles. Small organisms are unable to pass through the filter, so they’re kept out of the water you drink.

Do you live in a part of the world that has plenty of clean drinking water? If so, consider yourself lucky. Access to clean water is a huge problem in many parts of the world. In 2017, the World Health Organization (WHO) reported that 2.1 billion people—about a quarter of the world population—didn’t have access to clean drinking water at home. 

One modern solution to this issue is the LifeStraw, a 10-inch tube that filters dangerous contaminants from water as a person drinks through it. Tests show that LifeStraw removes 100 percent of bacteria and 99 percent of viruses from drinking water. Newer models even remove heavy metals, like lead. Its makers hope to bring clean drinking water to more people worldwide.

WONDERing just how clean your water is? If you’re concerned, you can also boil it. That’s another great way to purify water—boiling kills bacteria and viruses. You can also talk to a family member to find out where your water comes from and how it’s cleaned. Then, get back to enjoying a tall glass of clean water!

Standards: ESS2.C, ESS3.A, CCRA.R.4, CCRA.L.3, CCRA.L.6, CCRA.R.1, CCRA.R.2, CCRA.W.2, CCRA.W.9, CCRA.L.1, CCRA.L.2, CCRA.SL.1, CCRA.SL.1, CCRA.R.10,

Wonder What's Next?

Learn the BASSics of a traditional Mexican instrument with tomorrow’s Wonder of the Day!