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Experts say the world will be home to more than 8.5 billion people by 2030. That’s almost a billion more than now.
All those people will need food, but where will they get it? A bigger population will create more waste, but where will it go? Water and farmland must be protected from pollution. Many solutions will come from environmental engineering.
◀ Norma Alcantar is a chemical engineer. She used her knowledge on an environmental problem: polluted water. Her idea came from something she learned as a child from her grandmother in rural Mexico. People there boiled a prickly pear cactus and used the water to clean their drinking water. In her lab, Alcantar tested the plant. She found that the key was inside its leaves. She made biobeads, or pellets, from the cactus. Then she tested her idea on water in Haiti that got polluted after an earthquake. It worked.
A swale is a low place between two ridges. A bioswale is a low place full of grass, trees, or other plants. The plants let rainwater sink into the soil slowly. Water passes among the roots. The plants take out most of the pollutants. Engineers and landscapers both use these plantings. They help clean the water that flows into rivers, streams, or sewer systems. ▶
◀ When you flush a toilet, the water pushes everything toward the sewer. Up to six gallons may flow down the drain. (Newer toilets use less water.) What if you live in or near a desert, where water is scarce? Or in an area with no sewers? Environmental engineers have solved that problem with bio-toilets. Some use sand or sawdust to turn waste into compost. The process takes about 25 days. What’s left is dry material that does not smell. This material has only about 5 to 10 percent of its original mass.
▲ Winds on the ground can provide energy. But winds at high altitudes provide over four times more power. Engineers know this. So they ask, how can we use high-altitude winds to make power? The answer is wind turbines on kites. Of course, these are special kites. They’re about 100 feet long and made of thin strands of carbon. Flying up to 2,000 feet high, a kite’s turbines can generate 600 kilowatts of energy. That’s enough for around 300 homes. And it’s about twice the power a wind turbine on Earth makes.
◀ More than 800 million people in the world don’t get enough to eat. One reason is we don’t make enough food. Engineers have designed indoor farms as a solution. This farm is about half the size of a football field. It has thousands of LED lights. The farmers can control conditions like water and temperature. So, the lettuce here grows twice as fast as on a traditional farm. About 10,000 heads are harvested each day.
